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[PATCH v5 00/39] Richacls

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Contents

  [PATCH v5 00/39] Richacls Andreas Gruenbacher <andreas.gruenbacher@gmail.com> - 2015-07-22 15:10 +0200
    [PATCH v5 34/39] sunrpc: Allow to demand-allocate pages to encode into Andreas Gruenbacher <andreas.gruenbacher@gmail.com> - 2015-07-22 15:10 +0200
    [PATCH v5 10/39] richacl: Permission check algorithm Andreas Gruenbacher <andreas.gruenbacher@gmail.com> - 2015-07-22 15:10 +0200
    [PATCH v5 28/39] nfsd: Keep list of acls to dispose of in compoundargs Andreas Gruenbacher <andreas.gruenbacher@gmail.com> - 2015-07-22 15:10 +0200
    [PATCH v5 30/39] nfsd: Add richacl support Andreas Gruenbacher <andreas.gruenbacher@gmail.com> - 2015-07-22 15:10 +0200
    [PATCH v5 35/39] sunrpc: Add xdr_init_encode_pages Andreas Gruenbacher <andreas.gruenbacher@gmail.com> - 2015-07-22 15:10 +0200
    [PATCH v5 14/39] richacl: Create-time inheritance Andreas Gruenbacher <andreas.gruenbacher@gmail.com> - 2015-07-22 15:10 +0200
    [PATCH v5 33/39] ext4: Don't allow unmapped identifiers in richacls Andreas Gruenbacher <andreas.gruenbacher@gmail.com> - 2015-07-22 15:10 +0200
    [PATCH v5 36/39] nfs: Fix GETATTR bitmap verification Andreas Gruenbacher <andreas.gruenbacher@gmail.com> - 2015-07-22 15:10 +0200
    [PATCH v5 13/39] richacl: Check if an acl is equivalent to a file mode Andreas Gruenbacher <andreas.gruenbacher@gmail.com> - 2015-07-22 15:10 +0200
    [PATCH v5 15/39] richacl: Automatic Inheritance Andreas Gruenbacher <andreas.gruenbacher@gmail.com> - 2015-07-22 15:20 +0200
    [PATCH v5 18/39] ext4: Add richacl support Andreas Gruenbacher <andreas.gruenbacher@gmail.com> - 2015-07-22 15:20 +0200
    [PATCH v5 24/39] richacl: Set the other permissions to the other mask Andreas Gruenbacher <andreas.gruenbacher@gmail.com> - 2015-07-22 15:20 +0200
    [PATCH v5 21/39] richacl: Move everyone@ aces down the acl Andreas Gruenbacher <andreas.gruenbacher@gmail.com> - 2015-07-22 15:20 +0200
    [PATCH v5 19/39] ext4: Add richacl feature flag Andreas Gruenbacher <andreas.gruenbacher@gmail.com> - 2015-07-22 15:20 +0200
    [PATCH v5 27/39] richacl: Create richacl from mode values Andreas Gruenbacher <andreas.gruenbacher@gmail.com> - 2015-07-22 15:20 +0200
    [PATCH v5 31/39] nfsd: Add support for the v4.1 dacl attribute Andreas Gruenbacher <andreas.gruenbacher@gmail.com> - 2015-07-22 15:20 +0200
    [PATCH v5 22/39] richacl: Propagate everyone@ permissions to other aces Andreas Gruenbacher <andreas.gruenbacher@gmail.com> - 2015-07-22 15:20 +0200
    [PATCH v5 17/39] vfs: Add richacl permission checking Andreas Gruenbacher <andreas.gruenbacher@gmail.com> - 2015-07-22 15:20 +0200
    [PATCH v5 26/39] richacl: Apply the file masks to a richacl Andreas Gruenbacher <andreas.gruenbacher@gmail.com> - 2015-07-22 15:20 +0200
    [PATCH v5 32/39] richacl: Add support for unmapped identifiers Andreas Gruenbacher <andreas.gruenbacher@gmail.com> - 2015-07-22 15:20 +0200
    [PATCH v5 20/39] richacl: acl editing helper functions Andreas Gruenbacher <andreas.gruenbacher@gmail.com> - 2015-07-22 15:20 +0200
    [PATCH v5 23/39] richacl: Set the owner permissions to the owner mask Andreas Gruenbacher <andreas.gruenbacher@gmail.com> - 2015-07-22 15:20 +0200
    [PATCH v5 25/39] richacl: Isolate the owner and group classes Andreas Gruenbacher <andreas.gruenbacher@gmail.com> - 2015-07-22 15:20 +0200
    [PATCH v5 08/39] richacl: Compute maximum file masks from an acl Andreas Gruenbacher <andreas.gruenbacher@gmail.com> - 2015-07-22 15:30 +0200
    [PATCH v5 02/39] vfs: Add MAY_CREATE_FILE and MAY_CREATE_DIR permission flags Andreas Gruenbacher <andreas.gruenbacher@gmail.com> - 2015-07-22 15:30 +0200
    [PATCH v5 03/39] vfs: Add MAY_DELETE_SELF and MAY_DELETE_CHILD permission flags Andreas Gruenbacher <andreas.gruenbacher@gmail.com> - 2015-07-22 15:30 +0200
    [PATCH v5 01/39] vfs: Add IS_ACL() and IS_RICHACL() tests Andreas Gruenbacher <andreas.gruenbacher@gmail.com> - 2015-07-22 15:30 +0200
    [PATCH v5 11/39] vfs: Cache base_acl objects in inodes Andreas Gruenbacher <andreas.gruenbacher@gmail.com> - 2015-07-22 15:30 +0200
    [PATCH v5 05/39] vfs: Add permission flags for setting file attributes Andreas Gruenbacher <andreas.gruenbacher@gmail.com> - 2015-07-22 15:30 +0200
    [PATCH v5 12/39] vfs: Cache richacl in struct inode Andreas Gruenbacher <andreas.gruenbacher@gmail.com> - 2015-07-22 15:30 +0200
    [PATCH v5 07/39] richacl: Permission mapping functions Andreas Gruenbacher <andreas.gruenbacher@gmail.com> - 2015-07-22 15:30 +0200
    [PATCH v5 04/39] vfs: Make the inode passed to inode_change_ok non-const Andreas Gruenbacher <andreas.gruenbacher@gmail.com> - 2015-07-22 15:30 +0200
    [PATCH v5 16/39] richacl: xattr mapping functions Andreas Gruenbacher <andreas.gruenbacher@gmail.com> - 2015-07-22 15:30 +0200
    [PATCH v5 09/39] richacl: Update the file masks in chmod() Andreas Gruenbacher <andreas.gruenbacher@gmail.com> - 2015-07-22 15:30 +0200

Page 2 of 2 — ← Prev page 1 [2]

#1189922 — [PATCH v5 32/39] richacl: Add support for unmapped identifiers

From: Andreas Gruenbacher <agruenba@redhat.com>

Some remote file systems like nfs may return user or group identifiers that
cannot be mapped to local uids / gids.  Allow to represent such unmapped
identifiers in richacls.  (We still cannot represent unmapped owners and owning
groups, however.)

In the in-memory representation, the richacl is followed by a list of
NUL-terminated strings, with no padding.  Entries with an unmapped identifier
have the RICHACE_UNMAPPED_WHO flag set, and ace->e_id.offs specifies the offset
into this list.  Multiple entries can refer to the same offset.

The xattr representation is similar, but ace->e_id is ignored, and the list of
unmapped identifier strings contains a string for each acl entry whose
RICHACE_UNMAPPED_WHO flag is set.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
---
 fs/richacl_base.c       | 139 ++++++++++++++++++++++++++++++++++++++++++++----
 fs/richacl_compat.c     |  18 +++----
 fs/richacl_xattr.c      |  52 +++++++++++++++---
 include/linux/richacl.h |  33 ++++++++++--
 4 files changed, 212 insertions(+), 30 deletions(-)

diff --git a/fs/richacl_base.c b/fs/richacl_base.c
index 7d17279..8c52d4b 100644
--- a/fs/richacl_base.c
+++ b/fs/richacl_base.c
@@ -23,22 +23,25 @@
 MODULE_LICENSE("GPL");
 
 /**
- * richacl_alloc  -  allocate a richacl
+ * __richacl_alloc  -  allocate a richacl
  * @count:	number of entries
+ * @unmapped_size:	size to reserve for unmapped identifiers
  */
 struct richacl *
-richacl_alloc(int count, gfp_t gfp)
+__richacl_alloc(unsigned int count, size_t unmapped_size, gfp_t gfp)
 {
-	size_t size = sizeof(struct richacl) + count * sizeof(struct richace);
+	size_t size = sizeof(struct richacl) + count * sizeof(struct richace) +
+		      unmapped_size;
 	struct richacl *acl = kzalloc(size, gfp);
 
 	if (acl) {
 		atomic_set(&acl->a_base.ba_refcount, 1);
 		acl->a_count = count;
+		acl->a_unmapped_size = unmapped_size;
 	}
 	return acl;
 }
-EXPORT_SYMBOL_GPL(richacl_alloc);
+EXPORT_SYMBOL_GPL(__richacl_alloc);
 
 /**
  * richacl_clone  -  create a copy of a richacl
@@ -47,7 +50,8 @@ struct richacl *
 richacl_clone(const struct richacl *acl, gfp_t gfp)
 {
 	int count = acl->a_count;
-	size_t size = sizeof(struct richacl) + count * sizeof(struct richace);
+	size_t size = sizeof(struct richacl) + count * sizeof(struct richace) +
+		      acl->a_unmapped_size;
 	struct richacl *dup = kmalloc(size, gfp);
 
 	if (dup) {
@@ -59,6 +63,9 @@ richacl_clone(const struct richacl *acl, gfp_t gfp)
 
 /**
  * richace_copy  -  copy an acl entry
+ *
+ * If @from has an unmapped who value (from->e_flags & RICHACE_UNMAPPED_WHO),
+ * it can only be copied within the same acl!
  */
 void
 richace_copy(struct richace *to, const struct richace *from)
@@ -66,6 +73,82 @@ richace_copy(struct richace *to, const struct richace *from)
 	memcpy(to, from, sizeof(struct richace));
 }
 
+/**
+ * richacl_add_unmapped_identifier
+ * @pacl:	Pointer to an acl
+ * @pace:	acl entry within @acl
+ * @who:	unmapped identifier
+ * @len:	length of @who
+ * @gfp:	memory allocation flags
+ *
+ * Add an unmapped identifier to an acl, possibly reallocating the acl.
+ */
+int richacl_add_unmapped_identifier(struct richacl **pacl,
+				    struct richace **pace,
+				    const char *who,
+				    unsigned int len, gfp_t gfp)
+{
+	struct richacl *acl = *pacl;
+	size_t size = sizeof(struct richacl) +
+		      acl->a_count * sizeof(struct richace) +
+		      acl->a_unmapped_size + len + 1;
+	unsigned int index = *pace - acl->a_entries;
+
+	acl = krealloc(*pacl, size, gfp);
+	if (acl) {
+		char *unmapped = (char *)(acl->a_entries + acl->a_count);
+		struct richace *ace = acl->a_entries + index;
+
+		ace->e_flags |= RICHACE_UNMAPPED_WHO;
+		ace->e_flags &= ~RICHACE_SPECIAL_WHO;
+		ace->e_id.offs = acl->a_unmapped_size;
+		memcpy(unmapped + ace->e_id.offs, who, len);
+		unmapped[ace->e_id.offs + len] = 0;
+		acl->a_unmapped_size += len + 1;
+		*pace = ace;
+		*pacl = acl;
+		return 0;
+	}
+	return -1;
+}
+EXPORT_SYMBOL_GPL(richacl_add_unmapped_identifier);
+
+/**
+ * richace_unmapped_identifier  -  get unmapped identifier
+ * @acl:	acl containing @ace
+ * @ace:	acl entry
+ *
+ * Get the unmapped identifier of @ace as a NUL-terminated string, or NULL if
+ * @ace doesn't have an unmapped identifier.
+ */
+const char *richace_unmapped_identifier(const struct richace *ace,
+					const struct richacl *acl)
+{
+	const char *unmapped = (char *)(acl->a_entries + acl->a_count);
+
+	if (!(ace->e_flags & RICHACE_UNMAPPED_WHO))
+		return NULL;
+	return unmapped + ace->e_id.offs;
+}
+EXPORT_SYMBOL(richace_unmapped_identifier);
+
+/**
+ * richacl_has_unmapped_identifiers
+ *
+ * Check if an acl has unmapped identifiers.
+ */
+bool richacl_has_unmapped_identifiers(struct richacl *acl)
+{
+	struct richace *ace;
+
+	richacl_for_each_entry(ace, acl) {
+		if (ace->e_flags & RICHACE_UNMAPPED_WHO)
+			return true;
+	}
+	return false;
+}
+EXPORT_SYMBOL_GPL(richacl_has_unmapped_identifiers);
+
 /*
  * richacl_mask_to_mode  -  compute the file permission bits which correspond to @mask
  * @mask:	%RICHACE_* permission mask
@@ -209,7 +292,7 @@ static unsigned int richacl_allowed_to_who(struct richacl *acl,
 	richacl_for_each_entry_reverse(ace, acl) {
 		if (richace_is_inherit_only(ace))
 			continue;
-		if (richace_is_same_identifier(ace, who) ||
+		if (richace_is_same_identifier(acl, ace, who) ||
 		    richace_is_everyone(ace)) {
 			if (richace_is_allow(ace))
 				allowed |= ace->e_mask;
@@ -488,46 +571,73 @@ richacl_inherit(const struct richacl *dir_acl, int isdir)
 	const struct richace *dir_ace;
 	struct richacl *acl = NULL;
 	struct richace *ace;
-	int count = 0;
+	unsigned int count = 0, unmapped_size = 0, offset = 0;
+	const char *dir_unmapped;
+	char *unmapped;
 
 	if (isdir) {
 		richacl_for_each_entry(dir_ace, dir_acl) {
 			if (!richace_is_inheritable(dir_ace))
 				continue;
+
 			count++;
+			dir_unmapped =
+				richace_unmapped_identifier(dir_ace, dir_acl);
+			if (dir_unmapped)
+				unmapped_size += strlen(dir_unmapped) + 1;
 		}
 		if (!count)
 			return NULL;
-		acl = richacl_alloc(count, GFP_KERNEL);
+		acl = __richacl_alloc(count, unmapped_size, GFP_KERNEL);
 		if (!acl)
 			return ERR_PTR(-ENOMEM);
 		ace = acl->a_entries;
+		unmapped = (char *)(acl->a_entries + acl->a_count);
 		richacl_for_each_entry(dir_ace, dir_acl) {
 			if (!richace_is_inheritable(dir_ace))
 				continue;
+
 			richace_copy(ace, dir_ace);
 			if (dir_ace->e_flags & RICHACE_NO_PROPAGATE_INHERIT_ACE)
 				richace_clear_inheritance_flags(ace);
 			if ((dir_ace->e_flags & RICHACE_FILE_INHERIT_ACE) &&
 			    !(dir_ace->e_flags & RICHACE_DIRECTORY_INHERIT_ACE))
 				ace->e_flags |= RICHACE_INHERIT_ONLY_ACE;
+
+			dir_unmapped =
+				richace_unmapped_identifier(dir_ace, dir_acl);
+			if (dir_unmapped) {
+				size_t sz = strlen(dir_unmapped) + 1;
+
+				ace->e_id.offs = offset;
+				memcpy(unmapped, dir_unmapped, sz);
+				unmapped += sz;
+				offset += sz;
+			}
 			ace++;
 		}
 	} else {
 		richacl_for_each_entry(dir_ace, dir_acl) {
 			if (!(dir_ace->e_flags & RICHACE_FILE_INHERIT_ACE))
 				continue;
+
 			count++;
+			dir_unmapped =
+				richace_unmapped_identifier(dir_ace, dir_acl);
+			if (dir_unmapped)
+				unmapped_size += strlen(dir_unmapped) + 1;
 		}
 		if (!count)
 			return NULL;
-		acl = richacl_alloc(count, GFP_KERNEL);
+		acl = __richacl_alloc(count, unmapped_size, GFP_KERNEL);
 		if (!acl)
 			return ERR_PTR(-ENOMEM);
 		ace = acl->a_entries;
+		unmapped = (char *)(acl->a_entries + acl->a_count);
 		richacl_for_each_entry(dir_ace, dir_acl) {
 			if (!(dir_ace->e_flags & RICHACE_FILE_INHERIT_ACE))
 				continue;
+
 			richace_copy(ace, dir_ace);
 			richace_clear_inheritance_flags(ace);
 			/*
@@ -535,6 +645,17 @@ richacl_inherit(const struct richacl *dir_acl, int isdir)
 			 * non-directories, so clear it.
 			 */
 			ace->e_mask &= ~RICHACE_DELETE_CHILD;
+
+			dir_unmapped =
+				richace_unmapped_identifier(dir_ace, dir_acl);
+			if (dir_unmapped) {
+				size_t sz = strlen(dir_unmapped) + 1;
+
+				ace->e_id.offs = offset;
+				memcpy(unmapped, dir_unmapped, sz);
+				unmapped += sz;
+				offset += sz;
+			}
 			ace++;
 		}
 	}
diff --git a/fs/richacl_compat.c b/fs/richacl_compat.c
index b7d3990..eea964e 100644
--- a/fs/richacl_compat.c
+++ b/fs/richacl_compat.c
@@ -71,11 +71,13 @@ richacl_insert_entry(struct richacl_alloc *alloc, struct richace **ace)
 {
 	struct richacl *acl = alloc->acl;
 	unsigned int index = *ace - acl->a_entries;
-	size_t tail_size = (acl->a_count - index) * sizeof(struct richace);
+	size_t tail_size = (acl->a_count - index) * sizeof(struct richace) +
+			   acl->a_unmapped_size;
 
 	if (alloc->count == acl->a_count) {
 		size_t new_size = sizeof(struct richacl) +
-			(acl->a_count + 1) * sizeof(struct richace);
+			(acl->a_count + 1) * sizeof(struct richace) +
+			acl->a_unmapped_size;
 
 		acl = krealloc(acl, new_size, GFP_KERNEL);
 		if (!acl)
@@ -103,10 +105,6 @@ struct richace *richacl_append_entry(struct richacl_alloc *alloc)
 	struct richacl *acl = alloc->acl;
 	struct richace *ace = acl->a_entries + acl->a_count;
 
-	if (alloc->count > alloc->acl->a_count) {
-		acl->a_count++;
-		return ace;
-	}
 	return richacl_insert_entry(alloc, &ace) ? NULL : ace;
 }
 EXPORT_SYMBOL_GPL(richacl_append_entry);
@@ -260,12 +258,12 @@ __richacl_propagate_everyone(struct richacl_alloc *alloc, struct richace *who,
 		if (richace_is_inherit_only(ace))
 			continue;
 		if (richace_is_allow(ace)) {
-			if (richace_is_same_identifier(ace, who)) {
+			if (richace_is_same_identifier(acl, ace, who)) {
 				allow &= ~ace->e_mask;
 				allow_last = ace;
 			}
 		} else if (richace_is_deny(ace)) {
-			if (richace_is_same_identifier(ace, who))
+			if (richace_is_same_identifier(acl, ace, who))
 				allow &= ~ace->e_mask;
 			else if (allow & ace->e_mask)
 				allow_last = NULL;
@@ -587,7 +585,7 @@ __richacl_isolate_who(struct richacl_alloc *alloc, struct richace *who,
 	richacl_for_each_entry(ace, acl) {
 		if (richace_is_inherit_only(ace))
 			continue;
-		if (richace_is_same_identifier(ace, who) &&
+		if (richace_is_same_identifier(acl, ace, who) &&
 		    richace_is_deny(ace))
 			deny &= ~ace->e_mask;
 	}
@@ -604,7 +602,7 @@ __richacl_isolate_who(struct richacl_alloc *alloc, struct richace *who,
 		if (richace_is_inherit_only(ace))
 			continue;
 		if (richace_is_deny(ace)) {
-			if (richace_is_same_identifier(ace, who))
+			if (richace_is_same_identifier(acl, ace, who))
 				break;
 		} else if (richace_is_allow(ace) &&
 			   (ace->e_mask & deny)) {
diff --git a/fs/richacl_xattr.c b/fs/richacl_xattr.c
index d145915..1d40000 100644
--- a/fs/richacl_xattr.c
+++ b/fs/richacl_xattr.c
@@ -33,7 +33,8 @@ richacl_from_xattr(struct user_namespace *user_ns,
 	const struct richace_xattr *xattr_ace = (void *)(xattr_acl + 1);
 	struct richacl *acl;
 	struct richace *ace;
-	int count;
+	unsigned int count, offset;
+	char *unmapped;
 
 	if (size < sizeof(*xattr_acl) ||
 	    xattr_acl->a_version != RICHACL_XATTR_VERSION ||
@@ -43,10 +44,11 @@ richacl_from_xattr(struct user_namespace *user_ns,
 	count = le16_to_cpu(xattr_acl->a_count);
 	if (count > RICHACL_XATTR_MAX_COUNT)
 		return ERR_PTR(-EINVAL);
-	if (size != count * sizeof(*xattr_ace))
+	if (size < count * sizeof(*xattr_ace))
 		return ERR_PTR(-EINVAL);
+	size -= count * sizeof(*xattr_ace);
 
-	acl = richacl_alloc(count, GFP_NOFS);
+	acl = __richacl_alloc(count, size, GFP_NOFS);
 	if (!acl)
 		return ERR_PTR(-ENOMEM);
 
@@ -61,6 +63,16 @@ richacl_from_xattr(struct user_namespace *user_ns,
 	if (acl->a_other_mask & ~RICHACE_VALID_MASK)
 		goto fail_einval;
 
+	unmapped = (char *)(acl->a_entries + count);
+	if (size) {
+		char *xattr_unmapped = (char *)(xattr_ace + count);
+
+		if (xattr_unmapped[size - 1] != 0)
+			goto fail_einval;
+		memcpy(unmapped, xattr_unmapped, size);
+	}
+	offset = 0;
+
 	richacl_for_each_entry(ace, acl) {
 		ace->e_type  = le16_to_cpu(xattr_ace->e_type);
 		ace->e_flags = le16_to_cpu(xattr_ace->e_flags);
@@ -72,6 +84,14 @@ richacl_from_xattr(struct user_namespace *user_ns,
 			ace->e_id.special = le32_to_cpu(xattr_ace->e_id);
 			if (ace->e_id.special > RICHACE_EVERYONE_SPECIAL_ID)
 				goto fail_einval;
+		} else if (ace->e_flags & RICHACE_UNMAPPED_WHO) {
+			size_t sz;
+			if (offset == size)
+				goto fail_einval;
+			ace->e_id.offs = offset;
+			sz = strlen(unmapped) + 1;
+			unmapped += sz;
+			offset += sz;
 		} else if (ace->e_flags & RICHACE_IDENTIFIER_GROUP) {
 			ace->e_id.gid = make_kgid(user_ns, le32_to_cpu(xattr_ace->e_id));
 			if (!gid_valid(ace->e_id.gid))
@@ -84,10 +104,12 @@ richacl_from_xattr(struct user_namespace *user_ns,
 		if (ace->e_type > RICHACE_ACCESS_DENIED_ACE_TYPE ||
 		    (ace->e_mask & ~RICHACE_VALID_MASK))
 			goto fail_einval;
-
 		xattr_ace++;
 	}
 
+	if (offset != size)
+		goto fail_einval;
+
 	return acl;
 
 fail_einval:
@@ -103,8 +125,15 @@ size_t
 richacl_xattr_size(const struct richacl *acl)
 {
 	size_t size = sizeof(struct richacl_xattr);
+	const struct richace *ace;
 
 	size += sizeof(struct richace_xattr) * acl->a_count;
+	richacl_for_each_entry(ace, acl) {
+		const char *unmapped = richace_unmapped_identifier(ace, acl);
+
+		if (unmapped)
+			size += strlen(unmapped) + 1;
+	}
 	return size;
 }
 EXPORT_SYMBOL_GPL(richacl_xattr_size);
@@ -123,6 +152,7 @@ richacl_to_xattr(struct user_namespace *user_ns,
 	struct richace_xattr *xattr_ace;
 	const struct richace *ace;
 	size_t real_size;
+	char *xattr_unmapped;
 
 	real_size = richacl_xattr_size(acl);
 	if (!buffer)
@@ -139,13 +169,22 @@ richacl_to_xattr(struct user_namespace *user_ns,
 	xattr_acl->a_other_mask = cpu_to_le32(acl->a_other_mask);
 
 	xattr_ace = (void *)(xattr_acl + 1);
+	xattr_unmapped = (char *)(xattr_ace + acl->a_count);
 	richacl_for_each_entry(ace, acl) {
+		const char *who;
+
 		xattr_ace->e_type = cpu_to_le16(ace->e_type);
 		xattr_ace->e_flags = cpu_to_le16(ace->e_flags);
 		xattr_ace->e_mask = cpu_to_le32(ace->e_mask);
 		if (ace->e_flags & RICHACE_SPECIAL_WHO)
 			xattr_ace->e_id = cpu_to_le32(ace->e_id.special);
-		else if (ace->e_flags & RICHACE_IDENTIFIER_GROUP)
+		else if ((who = richace_unmapped_identifier(ace, acl))) {
+			size_t sz = strlen(who) + 1;
+
+			xattr_ace->e_id = 0;
+			memcpy(xattr_unmapped, who, sz);
+			xattr_unmapped += sz;
+		} else if (ace->e_flags & RICHACE_IDENTIFIER_GROUP)
 			xattr_ace->e_id =
 				cpu_to_le32(from_kgid(user_ns, ace->e_id.gid));
 		else
@@ -180,7 +219,8 @@ static void richacl_fix_xattr_userns(
 		return;
 	count = size / sizeof(*xattr_ace);
 	for (; count; count--, xattr_ace++) {
-		if (xattr_ace->e_flags & cpu_to_le16(RICHACE_SPECIAL_WHO))
+		if (xattr_ace->e_flags & cpu_to_le16(RICHACE_SPECIAL_WHO |
+						     RICHACE_UNMAPPED_WHO))
 			continue;
 		if (xattr_ace->e_flags & cpu_to_le16(RICHACE_IDENTIFIER_GROUP)) {
 			kgid_t gid = make_kgid(from, le32_to_cpu(xattr_ace->e_id));
diff --git a/include/linux/richacl.h b/include/linux/richacl.h
index eeb5bd9..39f5ce4 100644
--- a/include/linux/richacl.h
+++ b/include/linux/richacl.h
@@ -29,6 +29,7 @@ struct richace {
 		kuid_t		uid;
 		kgid_t		gid;
 		unsigned int	special;
+		unsigned short	offs;  /* unmapped offset */
 	} e_id;
 };
 
@@ -39,6 +40,7 @@ struct richacl {
 	unsigned int	a_other_mask;
 	unsigned short	a_count;
 	unsigned short	a_flags;
+	unsigned short	a_unmapped_size;
 	struct richace	a_entries[0];
 };
 
@@ -75,6 +77,7 @@ struct richacl {
 #define RICHACE_INHERIT_ONLY_ACE		0x0008
 #define RICHACE_IDENTIFIER_GROUP		0x0040
 #define RICHACE_INHERITED_ACE			0x0080
+#define RICHACE_UNMAPPED_WHO			0x2000
 #define RICHACE_SPECIAL_WHO			0x4000
 
 #define RICHACE_VALID_FLAGS (					\
@@ -84,6 +87,7 @@ struct richacl {
 	RICHACE_INHERIT_ONLY_ACE |				\
 	RICHACE_IDENTIFIER_GROUP |				\
 	RICHACE_INHERITED_ACE |					\
+	RICHACE_UNMAPPED_WHO |					\
 	RICHACE_SPECIAL_WHO)
 
 /* e_mask bitflags */
@@ -314,14 +318,28 @@ richace_is_deny(const struct richace *ace)
  * richace_is_same_identifier  -  are both identifiers the same?
  */
 static inline bool
-richace_is_same_identifier(const struct richace *a, const struct richace *b)
+richace_is_same_identifier(const struct richacl *acl,
+			   const struct richace *ace1,
+			   const struct richace *ace2)
 {
-	return !((a->e_flags ^ b->e_flags) &
-		 (RICHACE_SPECIAL_WHO | RICHACE_IDENTIFIER_GROUP)) &&
-	       !memcmp(&a->e_id, &b->e_id, sizeof(a->e_id));
+	const char *unmapped = (char *)(acl->a_entries + acl->a_count);
+
+	return !((ace1->e_flags ^ ace2->e_flags) &
+		 (RICHACE_SPECIAL_WHO |
+		  RICHACE_IDENTIFIER_GROUP |
+		  RICHACE_UNMAPPED_WHO)) &&
+	       ((ace1->e_flags & RICHACE_UNMAPPED_WHO) ?
+	        !strcmp(unmapped + ace1->e_id.offs,
+			unmapped + ace2->e_id.offs) :
+		!memcmp(&ace1->e_id, &ace2->e_id, sizeof(ace1->e_id)));
+}
+
+extern struct richacl *__richacl_alloc(unsigned int, size_t, gfp_t);
+static inline struct richacl *richacl_alloc(unsigned int count, gfp_t gfp)
+{
+	return __richacl_alloc(count, 0, gfp);
 }
 
-extern struct richacl *richacl_alloc(int, gfp_t);
 extern struct richacl *richacl_clone(const struct richacl *, gfp_t);
 extern void richace_copy(struct richace *, const struct richace *);
 extern int richacl_masks_to_mode(const struct richacl *);
@@ -331,6 +349,11 @@ extern void richacl_compute_max_masks(struct richacl *, kuid_t);
 extern struct richacl *richacl_chmod(struct richacl *, mode_t);
 extern int richacl_equiv_mode(const struct richacl *, mode_t *);
 extern struct richacl *richacl_inherit(const struct richacl *, int);
+extern int richacl_add_unmapped_identifier(struct richacl **, struct richace **,
+					   const char *, unsigned int, gfp_t);
+extern const char *richace_unmapped_identifier(const struct richace *,
+					       const struct richacl *);
+extern bool richacl_has_unmapped_identifiers(struct richacl *);
 
 /* richacl_inode.c */
 extern int richacl_permission(struct inode *, const struct richacl *, int);
-- 
2.4.3

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#1189925 — [PATCH v5 20/39] richacl: acl editing helper functions

From: Andreas Gruenbacher <agruenba@redhat.com>

The file masks in richacls make chmod and creating new files more
efficient than having to apply file permission bits to the acl directly.
They also allow us to regain permissions from an acl even after a
restrictive chmod, because the permissions in the acl itself are not
being destroyed.  In POSIX ACLs, the mask entry has a similar function.

Protocols like nfsv4 do not understand file masks.  For those protocols,
we need to compute nfs4 acls which represent the effective permissions
granted by a richacl: we need to "apply" the file masks to the acl.

This is the first in a series of richacl transformation patches; it
implements basic richacl editing functions.  The following patches
implement algorithms for transforming a richacl so that it can be
evaluated as a plain nfs4 acl, with identical permission check results.

Signed-off-by: Andreas Gruenbacher <agruen@kernel.org>
---
 fs/Makefile                    |   3 +-
 fs/richacl_compat.c            | 154 +++++++++++++++++++++++++++++++++++++++++
 include/linux/richacl_compat.h |  40 +++++++++++
 3 files changed, 196 insertions(+), 1 deletion(-)
 create mode 100644 fs/richacl_compat.c
 create mode 100644 include/linux/richacl_compat.h

diff --git a/fs/Makefile b/fs/Makefile
index baf385a..2d08c70 100644
--- a/fs/Makefile
+++ b/fs/Makefile
@@ -48,7 +48,8 @@ obj-$(CONFIG_SYSCTL)		+= drop_caches.o
 
 obj-$(CONFIG_FHANDLE)		+= fhandle.o
 obj-$(CONFIG_FS_RICHACL)	+= richacl.o
-richacl-y			:= richacl_base.o richacl_inode.o richacl_xattr.o
+richacl-y			:= richacl_base.o richacl_inode.o \
+				   richacl_xattr.o richacl_compat.o
 
 obj-y				+= quota/
 
diff --git a/fs/richacl_compat.c b/fs/richacl_compat.c
new file mode 100644
index 0000000..5bbf993
--- /dev/null
+++ b/fs/richacl_compat.c
@@ -0,0 +1,154 @@
+/*
+ * Copyright (C) 2006, 2010  Novell, Inc.
+ * Copyright (C) 2015  Red Hat, Inc.
+ * Written by Andreas Gruenbacher <agruen@kernel.org>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2, or (at your option) any
+ * later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ */
+
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/slab.h>
+#include <linux/richacl_compat.h>
+
+/**
+ * richacl_prepare  -  allocate richacl being constructed
+ *
+ * Allocate a richacl which can hold @count entries but which is initially
+ * empty.
+ */
+struct richacl *richacl_prepare(struct richacl_alloc *alloc, unsigned int count)
+{
+	alloc->acl = richacl_alloc(count, GFP_KERNEL);
+	if (!alloc->acl)
+		return NULL;
+	alloc->acl->a_count = 0;
+	alloc->count = count;
+	return alloc->acl;
+}
+EXPORT_SYMBOL_GPL(richacl_prepare);
+
+/**
+ * richacl_delete_entry  -  delete an entry in an acl
+ * @alloc:	acl and number of allocated entries
+ * @ace:	an entry in @alloc->acl
+ *
+ * Updates @ace so that it points to the entry before the deleted entry
+ * on return. (When deleting the first entry, @ace will point to the
+ * (non-existant) entry before the first entry). This behavior is the
+ * expected behavior when deleting entries while forward iterating over
+ * an acl.
+ */
+void
+richacl_delete_entry(struct richacl_alloc *alloc, struct richace **ace)
+{
+	void *end = alloc->acl->a_entries + alloc->acl->a_count;
+
+	memmove(*ace, *ace + 1, end - (void *)(*ace + 1));
+	(*ace)--;
+	alloc->acl->a_count--;
+}
+EXPORT_SYMBOL_GPL(richacl_delete_entry);
+
+/**
+ * richacl_insert_entry  -  insert an entry in an acl
+ * @alloc:	acl and number of allocated entries
+ * @ace:	entry before which the new entry shall be inserted
+ *
+ * Insert a new entry in @alloc->acl at position @ace and zero-initialize
+ * it.  This may require reallocating @alloc->acl.
+ */
+int
+richacl_insert_entry(struct richacl_alloc *alloc, struct richace **ace)
+{
+	struct richacl *acl = alloc->acl;
+	unsigned int index = *ace - acl->a_entries;
+	size_t tail_size = (acl->a_count - index) * sizeof(struct richace);
+
+	if (alloc->count == acl->a_count) {
+		size_t new_size = sizeof(struct richacl) +
+			(acl->a_count + 1) * sizeof(struct richace);
+
+		acl = krealloc(acl, new_size, GFP_KERNEL);
+		if (!acl)
+			return -1;
+		*ace = acl->a_entries + index;
+		alloc->acl = acl;
+		alloc->count++;
+	}
+
+	memmove(*ace + 1, *ace, tail_size);
+	memset(*ace, 0, sizeof(**ace));
+	acl->a_count++;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(richacl_insert_entry);
+
+/**
+ * richacl_append_entry  -  append an entry to an acl
+ * @alloc:		acl and number of allocated entries
+ *
+ * This may require reallocating @alloc->acl.
+ */
+struct richace *richacl_append_entry(struct richacl_alloc *alloc)
+{
+	struct richacl *acl = alloc->acl;
+	struct richace *ace = acl->a_entries + acl->a_count;
+
+	if (alloc->count > alloc->acl->a_count) {
+		acl->a_count++;
+		return ace;
+	}
+	return richacl_insert_entry(alloc, &ace) ? NULL : ace;
+}
+EXPORT_SYMBOL_GPL(richacl_append_entry);
+
+/**
+ * richace_change_mask  -  set the mask of @ace to @mask
+ * @alloc:	acl and number of allocated entries
+ * @ace:	entry to modify
+ * @mask:	new mask for @ace
+ *
+ * If @ace is inheritable, a inherit-only ace is inserted before @ace which
+ * includes the inheritable permissions of @ace and the inheritance flags of
+ * @ace are cleared before changing the mask.
+ *
+ * If @mask is 0, the original ace is turned into an inherit-only entry if
+ * there are any inheritable permissions, and removed otherwise.
+ *
+ * The returned @ace points to the modified or inserted effective-only acl
+ * entry if that entry exists, to the entry that has become inheritable-only,
+ * or else to the previous entry in the acl.
+ */
+static int
+richace_change_mask(struct richacl_alloc *alloc, struct richace **ace,
+			   unsigned int mask)
+{
+	if (mask && (*ace)->e_mask == mask)
+		(*ace)->e_flags &= ~RICHACE_INHERIT_ONLY_ACE;
+	else if (mask & ~RICHACE_POSIX_ALWAYS_ALLOWED) {
+		if (richace_is_inheritable(*ace)) {
+			if (richacl_insert_entry(alloc, ace))
+				return -1;
+			richace_copy(*ace, *ace + 1);
+			(*ace)->e_flags |= RICHACE_INHERIT_ONLY_ACE;
+			(*ace)++;
+			richace_clear_inheritance_flags(*ace);
+		}
+		(*ace)->e_mask = mask;
+	} else {
+		if (richace_is_inheritable(*ace))
+			(*ace)->e_flags |= RICHACE_INHERIT_ONLY_ACE;
+		else
+			richacl_delete_entry(alloc, ace);
+	}
+	return 0;
+}
diff --git a/include/linux/richacl_compat.h b/include/linux/richacl_compat.h
new file mode 100644
index 0000000..a9ff630
--- /dev/null
+++ b/include/linux/richacl_compat.h
@@ -0,0 +1,40 @@
+/*
+ * Copyright (C) 2015  Red Hat, Inc.
+ * Written by Andreas Gruenbacher <agruenba@redhat.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2, or (at your option) any
+ * later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ */
+
+#ifndef __RICHACL_COMPAT_H
+#define __RICHACL_COMPAT_H
+
+#include <linux/richacl.h>
+
+/**
+ * struct richacl_alloc  -  remember how many entries are actually allocated
+ * @acl:	acl with a_count <= @count
+ * @count:	the actual number of entries allocated in @acl
+ *
+ * We pass around this structure while modifying an acl so that we do
+ * not have to reallocate when we remove existing entries followed by
+ * adding new entries.
+ */
+struct richacl_alloc {
+	struct richacl *acl;
+	unsigned int count;
+};
+
+struct richacl *richacl_prepare(struct richacl_alloc *, unsigned int);
+struct richace *richacl_append_entry(struct richacl_alloc *);
+int richacl_insert_entry(struct richacl_alloc *, struct richace **);
+void richacl_delete_entry(struct richacl_alloc *, struct richace **);
+
+#endif  /* __RICHACL_COMPAT_H */
-- 
2.4.3

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#1189928 — [PATCH v5 23/39] richacl: Set the owner permissions to the owner mask

From: Andreas Gruenbacher <agruenba@redhat.com>

Change the acl so that owner@ is granted the permissions set in the owner mask.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
---
 fs/richacl_compat.c | 42 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)

diff --git a/fs/richacl_compat.c b/fs/richacl_compat.c
index b709cde..db33b63 100644
--- a/fs/richacl_compat.c
+++ b/fs/richacl_compat.c
@@ -399,3 +399,45 @@ richacl_propagate_everyone(struct richacl_alloc *alloc)
 	}
 	return 0;
 }
+
+/**
+ * richacl_set_owner_permissions  -  set the owner permissions to the owner mask
+ *
+ * Change the acl so that owner@ is granted the permissions set in the owner
+ * mask.  This leaves at most one efective owner@ allow entry at the beginning
+ * of the acl.
+ */
+static int
+richacl_set_owner_permissions(struct richacl_alloc *alloc)
+{
+	unsigned int x = RICHACE_POSIX_ALWAYS_ALLOWED;
+	unsigned int owner_mask = alloc->acl->a_owner_mask & ~x;
+	unsigned int denied = 0;
+	struct richace *ace;
+
+	if (!owner_mask)
+		return 0;
+
+	richacl_for_each_entry(ace, alloc->acl) {
+		if (richace_is_owner(ace)) {
+			if (!richace_is_inherit_only(ace))
+				richace_change_mask(alloc, &ace, 0);
+		} else {
+			if (richace_is_deny(ace))
+				denied |= ace->e_mask;
+		}
+	}
+
+	if (owner_mask & (denied |
+			  ~alloc->acl->a_other_mask |
+			  ~alloc->acl->a_group_mask)) {
+		ace = alloc->acl->a_entries;
+		if (richacl_insert_entry(alloc, &ace))
+			return -1;
+		ace->e_type = RICHACE_ACCESS_ALLOWED_ACE_TYPE;
+		ace->e_flags = RICHACE_SPECIAL_WHO;
+		ace->e_mask = owner_mask;
+		ace->e_id.special = RICHACE_OWNER_SPECIAL_ID;
+	}
+	return 0;
+}
-- 
2.4.3

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#1189929 — [PATCH v5 25/39] richacl: Isolate the owner and group classes

From: Andreas Gruenbacher <agruenba@redhat.com>

When applying the file masks to an acl, we need to ensure that no
process gets more permissions than allowed by its file mask.

This may require inserting an owner@ deny ace to ensure this if the
owner mask contains fewer permissions than the group or other mask.  For
example, when applying mode 0466 to the following acl:

   everyone@:rw::allow

A deny ace needs to be inserted so that the owner won't get elevated
write access:

   owner@:w::deny
   everyone@:rw::allow

Likewise, we may need to insert group class deny aces if the group mask
contains fewer permissions than the other mask.  For example, when
applying mode 0646 to the following acl:

   owner@:rw::allow
   everyone@:rw::allow

A deny ace needs to be inserted so that the owning group won't get
elevated write access:

   owner@:rw::allow
   group@:w::deny
   everyone@:rw::allow

Signed-off-by: Andreas Gruenbacher <agruen@kernel.org>
---
 fs/richacl_compat.c | 229 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 229 insertions(+)

diff --git a/fs/richacl_compat.c b/fs/richacl_compat.c
index 438859c..f18f59c 100644
--- a/fs/richacl_compat.c
+++ b/fs/richacl_compat.c
@@ -474,3 +474,232 @@ richacl_set_other_permissions(struct richacl_alloc *alloc)
 		richace_change_mask(alloc, &ace, other_mask);
 	return 0;
 }
+
+/**
+ * richacl_max_allowed  -  maximum permissions that anybody is allowed
+ */
+static unsigned int
+richacl_max_allowed(struct richacl *acl)
+{
+	struct richace *ace;
+	unsigned int allowed = 0;
+
+	richacl_for_each_entry_reverse(ace, acl) {
+		if (richace_is_inherit_only(ace))
+			continue;
+		if (richace_is_allow(ace))
+			allowed |= ace->e_mask;
+		else if (richace_is_deny(ace)) {
+			if (richace_is_everyone(ace))
+				allowed &= ~ace->e_mask;
+		}
+	}
+	return allowed;
+}
+
+/**
+ * richacl_isolate_owner_class  -  limit the owner class to the owner file mask
+ * @alloc:	acl and number of allocated entries
+ *
+ * POSIX requires that after a chmod, the owner class is granted no more
+ * permissions than the owner file permission bits.  For richacls, this
+ * means that the owner class must not be granted any permissions that the
+ * owner mask does not include.
+ *
+ * When we apply file masks to an acl which grant more permissions to the group
+ * or other class than to the owner class, we may end up in a situation where
+ * the owner is granted additional permissions from other aces.  For example,
+ * given this acl:
+ *
+ *    everyone:rwx::allow
+ *
+ * when file masks corresponding to mode 0466 are applied, after
+ * richacl_propagate_everyone() and __richacl_apply_masks(), we end up with:
+ *
+ *    owner@:r::allow
+ *    everyone@:rw::allow
+ *
+ * This acl still grants the owner rw access through the everyone@ allow ace.
+ * To fix this, we must deny the owner w access:
+ *
+ *    owner@:w::deny
+ *    owner@:r::allow
+ *    everyone@:rw::allow
+ */
+static int
+richacl_isolate_owner_class(struct richacl_alloc *alloc)
+{
+	struct richace *ace;
+	unsigned int allowed = 0;
+
+	allowed = richacl_max_allowed(alloc->acl);
+	if (allowed & ~alloc->acl->a_owner_mask) {
+		/*
+		 * Figure out if we can update an existig OWNER@ DENY entry.
+		 */
+		richacl_for_each_entry(ace, alloc->acl) {
+			if (richace_is_inherit_only(ace))
+				continue;
+			if (richace_is_deny(ace)) {
+				if (richace_is_owner(ace))
+					break;
+			} else if (richace_is_allow(ace)) {
+				ace = alloc->acl->a_entries + alloc->acl->a_count;
+				break;
+			}
+		}
+		if (ace != alloc->acl->a_entries + alloc->acl->a_count) {
+			if (richace_change_mask(alloc, &ace, ace->e_mask |
+					(allowed & ~alloc->acl->a_owner_mask)))
+				return -1;
+		} else {
+			/* Insert an owner@ deny entry at the front. */
+			ace = alloc->acl->a_entries;
+			if (richacl_insert_entry(alloc, &ace))
+				return -1;
+			ace->e_type = RICHACE_ACCESS_DENIED_ACE_TYPE;
+			ace->e_flags = RICHACE_SPECIAL_WHO;
+			ace->e_mask = allowed & ~alloc->acl->a_owner_mask;
+			ace->e_id.special = RICHACE_OWNER_SPECIAL_ID;
+		}
+	}
+	return 0;
+}
+
+/**
+ * __richacl_isolate_who  -  isolate entry from everyone@ allow entry
+ * @alloc:	acl and number of allocated entries
+ * @who:	identifier to isolate
+ * @deny:	permissions this identifier should not be allowed
+ *
+ * See richacl_isolate_group_class().
+ */
+static int
+__richacl_isolate_who(struct richacl_alloc *alloc, struct richace *who,
+		      unsigned int deny)
+{
+	struct richacl *acl = alloc->acl;
+	struct richace *ace;
+	int n;
+	/*
+	 * Compute the permissions already denied to @who.
+	 */
+	richacl_for_each_entry(ace, acl) {
+		if (richace_is_inherit_only(ace))
+			continue;
+		if (richace_is_same_identifier(ace, who) &&
+		    richace_is_deny(ace))
+			deny &= ~ace->e_mask;
+	}
+	if (!deny)
+		return 0;
+
+	/*
+	 * Figure out if we can update an existig deny entry.  Start from the
+	 * entry before the trailing everyone@ allow entry. We will not hit
+	 * everyone@ entries in the loop.
+	 */
+	for (n = acl->a_count - 2; n != -1; n--) {
+		ace = acl->a_entries + n;
+		if (richace_is_inherit_only(ace))
+			continue;
+		if (richace_is_deny(ace)) {
+			if (richace_is_same_identifier(ace, who))
+				break;
+		} else if (richace_is_allow(ace) &&
+			   (ace->e_mask & deny)) {
+			n = -1;
+			break;
+		}
+	}
+	if (n != -1) {
+		if (richace_change_mask(alloc, &ace, ace->e_mask | deny))
+			return -1;
+	} else {
+		/*
+		 * Insert a new entry before the trailing everyone@ deny entry.
+		 */
+		struct richace who_copy;
+
+		richace_copy(&who_copy, who);
+		ace = acl->a_entries + acl->a_count - 1;
+		if (richacl_insert_entry(alloc, &ace))
+			return -1;
+		richace_copy(ace, &who_copy);
+		ace->e_type = RICHACE_ACCESS_DENIED_ACE_TYPE;
+		richace_clear_inheritance_flags(ace);
+		ace->e_mask = deny;
+	}
+	return 0;
+}
+
+/**
+ * richacl_isolate_group_class  -  limit the group class to the group file mask
+ * @alloc:	acl and number of allocated entries
+ *
+ * POSIX requires that after a chmod, the group class is granted no more
+ * permissions than the group file permission bits.  For richacls, this
+ * means that the group class must not be granted any permissions that the
+ * group mask does not include.
+ *
+ * When we apply file masks to an acl which grant more permissions to the other
+ * class than to the group class, we may end up in a situation where processes
+ * in the group class are granted additional permission from other aces.  For
+ * example, given this acl:
+ *
+ *    joe:rwx::allow
+ *    everyone:rwx::allow
+ *
+ * when file masks corresponding to mode 0646 are applied, after
+ * richacl_propagate_everyone() and __richacl_apply_masks(), we end up with:
+ *
+ *    joe:r::allow
+ *    owner@:rw::allow
+ *    group@:r::allow
+ *    everyone@:rw::allow
+ *
+ * This acl still grants joe and group@ rw access through the everyone@ allow
+ * ace.  To fix this, we must deny w access to group class aces before the
+ * everyone@ allow ace at the end of the acl:
+ *
+ *    joe:r::allow
+ *    owner@:rw::allow
+ *    group@:r::allow
+ *    joe:w::deny
+ *    group@:w::deny
+ *    everyone@:rw::allow
+ */
+static int
+richacl_isolate_group_class(struct richacl_alloc *alloc)
+{
+	struct richace who = {
+		.e_flags = RICHACE_SPECIAL_WHO,
+		.e_id.special = RICHACE_GROUP_SPECIAL_ID,
+	};
+	unsigned int deny;
+
+	deny = alloc->acl->a_other_mask & ~alloc->acl->a_group_mask;
+
+	if (deny) {
+		unsigned int n;
+
+		if (__richacl_isolate_who(alloc, &who, deny))
+			return -1;
+		/*
+		 * Start from the entry before the trailing everyone@ allow
+		 * entry.  We will not hit everyone@ entries in the loop.
+		 */
+		for (n = alloc->acl->a_count - 1; n != -1; n--) {
+			struct richace *ace = alloc->acl->a_entries + n;
+
+			if (richace_is_inherit_only(ace) ||
+			    richace_is_owner(ace) ||
+			    richace_is_group(ace) ||
+			    richace_is_everyone(ace))
+				continue;
+			if (__richacl_isolate_who(alloc, ace, deny))
+				return -1;
+		}
+	}
+	return 0;
+}
-- 
2.4.3

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#1189930 — [PATCH v5 08/39] richacl: Compute maximum file masks from an acl

From: Andreas Gruenbacher <agruenba@redhat.com>

Compute upper bound owner, group, and other file masks with as few
permissions as possible without denying any permissions that the NFSv4
acl in a richacl grants.

This algorithm is used when a file inherits an acl at create time and
when an acl is set via a mechanism that does not provide file masks
(such as setting an acl via nfsd).  When user-space sets an acl via
setxattr, the extended attribute already includes the file masks.

Setting an acl also sets the file mode permission bits: they are
determined by the file masks; see richacl_masks_to_mode().

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: J. Bruce Fields <bfields@redhat.com>
---
 fs/richacl_base.c       | 156 ++++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/richacl.h |   1 +
 2 files changed, 157 insertions(+)

diff --git a/fs/richacl_base.c b/fs/richacl_base.c
index d12f984..23e9824 100644
--- a/fs/richacl_base.c
+++ b/fs/richacl_base.c
@@ -178,3 +178,159 @@ richacl_want_to_mask(unsigned int want)
 	return mask;
 }
 EXPORT_SYMBOL_GPL(richacl_want_to_mask);
+
+/*
+ * Note: functions like richacl_allowed_to_who(), richacl_group_class_allowed(),
+ * and richacl_compute_max_masks() iterate through the entire acl in reverse
+ * order as an optimization.
+ *
+ * In the standard algorithm, aces are considered in forward order.  When a
+ * process matches an ace, the permissions in the ace are either allowed or
+ * denied depending on the ace type.  Once a permission has been allowed or
+ * denied, it is no longer considered in further aces.
+ *
+ * By iterating through the acl in reverse order, we can compute the same
+ * result without having to keep track of which permissions have been allowed
+ * and denied already.
+ */
+
+/**
+ * richacl_allowed_to_who  -  permissions allowed to a specific who value
+ *
+ * Compute the maximum mask values allowed to a specific who value, taking
+ * everyone@ aces into account.
+ */
+static unsigned int richacl_allowed_to_who(struct richacl *acl,
+					   struct richace *who)
+{
+	struct richace *ace;
+	unsigned int allowed = 0;
+
+	richacl_for_each_entry_reverse(ace, acl) {
+		if (richace_is_inherit_only(ace))
+			continue;
+		if (richace_is_same_identifier(ace, who) ||
+		    richace_is_everyone(ace)) {
+			if (richace_is_allow(ace))
+				allowed |= ace->e_mask;
+			else if (richace_is_deny(ace))
+				allowed &= ~ace->e_mask;
+		}
+	}
+	return allowed;
+}
+
+/**
+ * richacl_group_class_allowed  -  maximum permissions the group class is allowed
+ *
+ * Compute the maximum mask values allowed to a process in the group class
+ * (i.e., a process which is not the owner but is in the owning group or
+ * matches a user or group acl entry).  This includes permissions granted or
+ * denied by everyone@ aces.
+ *
+ * See richacl_compute_max_masks().
+ */
+static unsigned int richacl_group_class_allowed(struct richacl *acl)
+{
+	struct richace *ace;
+	unsigned int everyone_allowed = 0, group_class_allowed = 0;
+	int had_group_ace = 0;
+
+	richacl_for_each_entry_reverse(ace, acl) {
+		if (richace_is_inherit_only(ace) ||
+		    richace_is_owner(ace))
+			continue;
+
+		if (richace_is_everyone(ace)) {
+			if (richace_is_allow(ace))
+				everyone_allowed |= ace->e_mask;
+			else if (richace_is_deny(ace))
+				everyone_allowed &= ~ace->e_mask;
+		} else {
+			group_class_allowed |=
+				richacl_allowed_to_who(acl, ace);
+
+			if (richace_is_group(ace))
+				had_group_ace = 1;
+		}
+	}
+	/*
+	 * If the acl doesn't contain any group@ aces, richacl_allowed_to_who()
+	 * wasn't called for the owning group.  We could make that call now, but
+	 * we already know the result (everyone_allowed).
+	 */
+	if (!had_group_ace)
+		group_class_allowed |= everyone_allowed;
+	return group_class_allowed;
+}
+
+/**
+ * richacl_compute_max_masks  -  compute upper bound masks
+ *
+ * Computes upper bound owner, group, and other masks so that none of
+ * the mask flags allowed by the acl are disabled (for any choice of the
+ * file owner or group membership).
+ */
+void richacl_compute_max_masks(struct richacl *acl, kuid_t owner)
+{
+	unsigned int gmask = ~0;
+	struct richace *ace;
+
+	/*
+	 * @gmask contains all permissions which the group class is ever
+	 * allowed.  We use it to avoid adding permissions to the group mask
+	 * from everyone@ allow aces which the group class is always denied
+	 * through other aces.  For example, the following acl would otherwise
+	 * result in a group mask of rw:
+	 *
+	 *	group@:w::deny
+	 *	everyone@:rw::allow
+	 *
+	 * Avoid computing @gmask for acls which do not include any group class
+	 * deny aces: in such acls, the group class is never denied any
+	 * permissions from everyone@ allow aces, and the group class cannot
+	 * have fewer permissions than the other class.
+	 */
+
+restart:
+	acl->a_owner_mask = 0;
+	acl->a_group_mask = 0;
+	acl->a_other_mask = 0;
+
+	richacl_for_each_entry_reverse(ace, acl) {
+		if (richace_is_inherit_only(ace))
+			continue;
+
+		if (richace_is_owner(ace) ||
+		    (richace_is_unix_user(ace) &&
+		     uid_eq(ace->e_id.uid, owner))) {
+			if (richace_is_allow(ace))
+				acl->a_owner_mask |= ace->e_mask;
+			else if (richace_is_deny(ace))
+				acl->a_owner_mask &= ~ace->e_mask;
+		} else if (richace_is_everyone(ace)) {
+			if (richace_is_allow(ace)) {
+				acl->a_owner_mask |= ace->e_mask;
+				acl->a_group_mask |= ace->e_mask & gmask;
+				acl->a_other_mask |= ace->e_mask;
+			} else if (richace_is_deny(ace)) {
+				acl->a_owner_mask &= ~ace->e_mask;
+				acl->a_group_mask &= ~ace->e_mask;
+				acl->a_other_mask &= ~ace->e_mask;
+			}
+		} else {
+			if (richace_is_allow(ace)) {
+				acl->a_owner_mask |= ace->e_mask & gmask;
+				acl->a_group_mask |= ace->e_mask & gmask;
+			} else if (richace_is_deny(ace) && gmask == ~0) {
+				gmask = richacl_group_class_allowed(acl);
+				if (likely(gmask != ~0))
+					/* should always be true */
+					goto restart;
+			}
+		}
+	}
+
+	acl->a_flags &= ~RICHACL_MASKED;
+}
+EXPORT_SYMBOL_GPL(richacl_compute_max_masks);
diff --git a/include/linux/richacl.h b/include/linux/richacl.h
index 1ae0bf8..90baca3 100644
--- a/include/linux/richacl.h
+++ b/include/linux/richacl.h
@@ -301,5 +301,6 @@ extern void richace_copy(struct richace *, const struct richace *);
 extern int richacl_masks_to_mode(const struct richacl *);
 extern unsigned int richacl_mode_to_mask(mode_t);
 extern unsigned int richacl_want_to_mask(unsigned int);
+extern void richacl_compute_max_masks(struct richacl *, kuid_t);
 
 #endif /* __RICHACL_H */
-- 
2.4.3

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#1189931 — [PATCH v5 02/39] vfs: Add MAY_CREATE_FILE and MAY_CREATE_DIR permission flags

From: Andreas Gruenbacher <agruenba@redhat.com>

Richacls distinguish between creating non-directories and directories. To
support that, add an isdir parameter to may_create(). When checking
inode_permission() for create permission, pass in an additional MAY_CREATE_FILE
or MAY_CREATE_DIR mask flag.

To allow checking for delete *and* create access when replacing an existing
file via vfs_rename(), add a replace parameter to may_delete().

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
---
 fs/namei.c         | 42 ++++++++++++++++++++++++------------------
 include/linux/fs.h |  2 ++
 2 files changed, 26 insertions(+), 18 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index 23dfaae..1e2b1fa 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -453,7 +453,8 @@ static int sb_permission(struct super_block *sb, struct inode *inode, int mask)
  * this, letting us set arbitrary permissions for filesystem access without
  * changing the "normal" UIDs which are used for other things.
  *
- * When checking for MAY_APPEND, MAY_WRITE must also be set in @mask.
+ * When checking for MAY_APPEND, MAY_CREATE_FILE, MAY_CREATE_DIR,
+ * MAY_WRITE must also be set in @mask.
  */
 int inode_permission(struct inode *inode, int mask)
 {
@@ -2517,10 +2518,11 @@ EXPORT_SYMBOL(__check_sticky);
  * 10. We don't allow removal of NFS sillyrenamed files; it's handled by
  *     nfs_async_unlink().
  */
-static int may_delete(struct inode *dir, struct dentry *victim, bool isdir)
+static int may_delete(struct inode *dir, struct dentry *victim,
+		      bool isdir, bool replace)
 {
 	struct inode *inode = d_backing_inode(victim);
-	int error;
+	int error, mask = MAY_WRITE | MAY_EXEC;
 
 	if (d_is_negative(victim))
 		return -ENOENT;
@@ -2529,7 +2531,9 @@ static int may_delete(struct inode *dir, struct dentry *victim, bool isdir)
 	BUG_ON(victim->d_parent->d_inode != dir);
 	audit_inode_child(dir, victim, AUDIT_TYPE_CHILD_DELETE);
 
-	error = inode_permission(dir, MAY_WRITE | MAY_EXEC);
+	if (replace)
+		mask |= isdir ? MAY_CREATE_DIR : MAY_CREATE_FILE;
+	error = inode_permission(dir, mask);
 	if (error)
 		return error;
 	if (IS_APPEND(dir))
@@ -2560,14 +2564,16 @@ static int may_delete(struct inode *dir, struct dentry *victim, bool isdir)
  *  3. We should have write and exec permissions on dir
  *  4. We can't do it if dir is immutable (done in permission())
  */
-static inline int may_create(struct inode *dir, struct dentry *child)
+static inline int may_create(struct inode *dir, struct dentry *child, bool isdir)
 {
+	int mask = isdir ? MAY_CREATE_DIR : MAY_CREATE_FILE;
+
 	audit_inode_child(dir, child, AUDIT_TYPE_CHILD_CREATE);
 	if (child->d_inode)
 		return -EEXIST;
 	if (IS_DEADDIR(dir))
 		return -ENOENT;
-	return inode_permission(dir, MAY_WRITE | MAY_EXEC);
+	return inode_permission(dir, MAY_WRITE | MAY_EXEC | mask);
 }
 
 /*
@@ -2617,7 +2623,7 @@ EXPORT_SYMBOL(unlock_rename);
 int vfs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
 		bool want_excl)
 {
-	int error = may_create(dir, dentry);
+	int error = may_create(dir, dentry, false);
 	if (error)
 		return error;
 
@@ -3462,7 +3468,7 @@ EXPORT_SYMBOL(user_path_create);
 
 int vfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev)
 {
-	int error = may_create(dir, dentry);
+	int error = may_create(dir, dentry, false);
 
 	if (error)
 		return error;
@@ -3554,7 +3560,7 @@ SYSCALL_DEFINE3(mknod, const char __user *, filename, umode_t, mode, unsigned, d
 
 int vfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 {
-	int error = may_create(dir, dentry);
+	int error = may_create(dir, dentry, true);
 	unsigned max_links = dir->i_sb->s_max_links;
 
 	if (error)
@@ -3635,7 +3641,7 @@ EXPORT_SYMBOL(dentry_unhash);
 
 int vfs_rmdir(struct inode *dir, struct dentry *dentry)
 {
-	int error = may_delete(dir, dentry, 1);
+	int error = may_delete(dir, dentry, true, false);
 
 	if (error)
 		return error;
@@ -3757,7 +3763,7 @@ SYSCALL_DEFINE1(rmdir, const char __user *, pathname)
 int vfs_unlink(struct inode *dir, struct dentry *dentry, struct inode **delegated_inode)
 {
 	struct inode *target = dentry->d_inode;
-	int error = may_delete(dir, dentry, 0);
+	int error = may_delete(dir, dentry, false, false);
 
 	if (error)
 		return error;
@@ -3891,7 +3897,7 @@ SYSCALL_DEFINE1(unlink, const char __user *, pathname)
 
 int vfs_symlink(struct inode *dir, struct dentry *dentry, const char *oldname)
 {
-	int error = may_create(dir, dentry);
+	int error = may_create(dir, dentry, false);
 
 	if (error)
 		return error;
@@ -3974,7 +3980,7 @@ int vfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_de
 	if (!inode)
 		return -ENOENT;
 
-	error = may_create(dir, new_dentry);
+	error = may_create(dir, new_dentry, false);
 	if (error)
 		return error;
 
@@ -4162,19 +4168,19 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 	if (source == target)
 		return 0;
 
-	error = may_delete(old_dir, old_dentry, is_dir);
+	error = may_delete(old_dir, old_dentry, is_dir, false);
 	if (error)
 		return error;
 
 	if (!target) {
-		error = may_create(new_dir, new_dentry);
+		error = may_create(new_dir, new_dentry, is_dir);
 	} else {
 		new_is_dir = d_is_dir(new_dentry);
 
 		if (!(flags & RENAME_EXCHANGE))
-			error = may_delete(new_dir, new_dentry, is_dir);
+			error = may_delete(new_dir, new_dentry, is_dir, true);
 		else
-			error = may_delete(new_dir, new_dentry, new_is_dir);
+			error = may_delete(new_dir, new_dentry, new_is_dir, true);
 	}
 	if (error)
 		return error;
@@ -4437,7 +4443,7 @@ SYSCALL_DEFINE2(rename, const char __user *, oldname, const char __user *, newna
 
 int vfs_whiteout(struct inode *dir, struct dentry *dentry)
 {
-	int error = may_create(dir, dentry);
+	int error = may_create(dir, dentry, false);
 	if (error)
 		return error;
 
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 44e696e..9c44f27 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -81,6 +81,8 @@ typedef void (dax_iodone_t)(struct buffer_head *bh_map, int uptodate);
 #define MAY_CHDIR		0x00000040
 /* called from RCU mode, don't block */
 #define MAY_NOT_BLOCK		0x00000080
+#define MAY_CREATE_FILE		0x00000100
+#define MAY_CREATE_DIR		0x00000200
 
 /*
  * flags in file.f_mode.  Note that FMODE_READ and FMODE_WRITE must correspond
-- 
2.4.3

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#1189933 — [PATCH v5 03/39] vfs: Add MAY_DELETE_SELF and MAY_DELETE_CHILD permission flags

From: Andreas Gruenbacher <agruenba@redhat.com>

Normally, deleting a file requires write and execute access to the parent
directory.  With Richacls, a process with MAY_DELETE_SELF access to a file may
delete the file even without write access to the parent directory.

To support that, pass the MAY_DELETE_CHILD mask flag to inode_permission() when
checking for delete access inside a directory, and MAY_DELETE_SELF when
checking for delete access to a file itelf.

The MAY_DELETE_SELF permission does not override the sticky directory check.
It probably should.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
---
 fs/namei.c         | 15 +++++++++++----
 include/linux/fs.h |  2 ++
 2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index 1e2b1fa..86be72c 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -454,7 +454,7 @@ static int sb_permission(struct super_block *sb, struct inode *inode, int mask)
  * changing the "normal" UIDs which are used for other things.
  *
  * When checking for MAY_APPEND, MAY_CREATE_FILE, MAY_CREATE_DIR,
- * MAY_WRITE must also be set in @mask.
+ * MAY_DELETE_CHILD, MAY_DELETE_SELF, MAY_WRITE must also be set in @mask.
  */
 int inode_permission(struct inode *inode, int mask)
 {
@@ -2522,7 +2522,7 @@ static int may_delete(struct inode *dir, struct dentry *victim,
 		      bool isdir, bool replace)
 {
 	struct inode *inode = d_backing_inode(victim);
-	int error, mask = MAY_WRITE | MAY_EXEC;
+	int error, mask = MAY_EXEC;
 
 	if (d_is_negative(victim))
 		return -ENOENT;
@@ -2532,8 +2532,15 @@ static int may_delete(struct inode *dir, struct dentry *victim,
 	audit_inode_child(dir, victim, AUDIT_TYPE_CHILD_DELETE);
 
 	if (replace)
-		mask |= isdir ? MAY_CREATE_DIR : MAY_CREATE_FILE;
-	error = inode_permission(dir, mask);
+		mask |= MAY_WRITE | (isdir ? MAY_CREATE_DIR : MAY_CREATE_FILE);
+	error = inode_permission(dir, mask | MAY_WRITE | MAY_DELETE_CHILD);
+	if (error && IS_RICHACL(inode)) {
+		/* Deleting is also permitted with MAY_EXEC on the directory
+		 * and MAY_DELETE_SELF on the inode.  */
+		if (!inode_permission(inode, MAY_DELETE_SELF) &&
+		    !inode_permission(dir, mask))
+			error = 0;
+	}
 	if (error)
 		return error;
 	if (IS_APPEND(dir))
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 9c44f27..abf5b0e 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -83,6 +83,8 @@ typedef void (dax_iodone_t)(struct buffer_head *bh_map, int uptodate);
 #define MAY_NOT_BLOCK		0x00000080
 #define MAY_CREATE_FILE		0x00000100
 #define MAY_CREATE_DIR		0x00000200
+#define MAY_DELETE_CHILD	0x00000400
+#define MAY_DELETE_SELF		0x00000800
 
 /*
  * flags in file.f_mode.  Note that FMODE_READ and FMODE_WRITE must correspond
-- 
2.4.3

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#1189934 — [PATCH v5 01/39] vfs: Add IS_ACL() and IS_RICHACL() tests

From: Andreas Gruenbacher <agruenba@redhat.com>

The vfs does not apply the umask for file systems that support acls. The test
used for this used to be called IS_POSIXACL(). Switch to a new IS_ACL() test to
check for either posix acls or richacls instead. Add a new MS_RICHACL flag and
IS_RICHACL() test for richacls alone. The IS_POSIXACL() test is still needed
by file systems that specifically support POSIX ACLs, like nfsd.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
---
 fs/Kconfig              |  3 +++
 fs/namei.c              |  8 ++++----
 include/linux/fs.h      | 12 ++++++++++++
 include/uapi/linux/fs.h |  3 ++-
 4 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/fs/Kconfig b/fs/Kconfig
index 011f433..3e09c06 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -59,6 +59,9 @@ endif # BLOCK
 config FS_POSIX_ACL
 	def_bool n
 
+config FS_RICHACL
+	def_bool n
+
 config EXPORTFS
 	tristate
 
diff --git a/fs/namei.c b/fs/namei.c
index ae4e4c1..23dfaae 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2766,7 +2766,7 @@ static int atomic_open(struct nameidata *nd, struct dentry *dentry,
 	}
 
 	mode = op->mode;
-	if ((open_flag & O_CREAT) && !IS_POSIXACL(dir))
+	if ((open_flag & O_CREAT) && !IS_ACL(dir))
 		mode &= ~current_umask();
 
 	excl = (open_flag & (O_EXCL | O_CREAT)) == (O_EXCL | O_CREAT);
@@ -2950,7 +2950,7 @@ static int lookup_open(struct nameidata *nd, struct path *path,
 	/* Negative dentry, just create the file */
 	if (!dentry->d_inode && (op->open_flag & O_CREAT)) {
 		umode_t mode = op->mode;
-		if (!IS_POSIXACL(dir->d_inode))
+		if (!IS_ACL(dir->d_inode))
 			mode &= ~current_umask();
 		/*
 		 * This write is needed to ensure that a
@@ -3521,7 +3521,7 @@ retry:
 	if (IS_ERR(dentry))
 		return PTR_ERR(dentry);
 
-	if (!IS_POSIXACL(path.dentry->d_inode))
+	if (!IS_ACL(path.dentry->d_inode))
 		mode &= ~current_umask();
 	error = security_path_mknod(&path, dentry, mode, dev);
 	if (error)
@@ -3590,7 +3590,7 @@ retry:
 	if (IS_ERR(dentry))
 		return PTR_ERR(dentry);
 
-	if (!IS_POSIXACL(path.dentry->d_inode))
+	if (!IS_ACL(path.dentry->d_inode))
 		mode &= ~current_umask();
 	error = security_path_mkdir(&path, dentry, mode);
 	if (!error)
diff --git a/include/linux/fs.h b/include/linux/fs.h
index cc008c3..44e696e 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1770,6 +1770,12 @@ struct super_operations {
 #define IS_IMMUTABLE(inode)	((inode)->i_flags & S_IMMUTABLE)
 #define IS_POSIXACL(inode)	__IS_FLG(inode, MS_POSIXACL)
 
+#ifdef CONFIG_FS_RICHACL
+#define IS_RICHACL(inode)	__IS_FLG(inode, MS_RICHACL)
+#else
+#define IS_RICHACL(inode)	0
+#endif
+
 #define IS_DEADDIR(inode)	((inode)->i_flags & S_DEAD)
 #define IS_NOCMTIME(inode)	((inode)->i_flags & S_NOCMTIME)
 #define IS_SWAPFILE(inode)	((inode)->i_flags & S_SWAPFILE)
@@ -1783,6 +1789,12 @@ struct super_operations {
 				 (inode)->i_rdev == WHITEOUT_DEV)
 
 /*
+ * IS_ACL() tells the VFS to not apply the umask
+ * and use check_acl for acl permission checks when defined.
+ */
+#define IS_ACL(inode)		__IS_FLG(inode, MS_POSIXACL | MS_RICHACL)
+
+/*
  * Inode state bits.  Protected by inode->i_lock
  *
  * Three bits determine the dirty state of the inode, I_DIRTY_SYNC,
diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h
index 9b964a5..6ac6bc9 100644
--- a/include/uapi/linux/fs.h
+++ b/include/uapi/linux/fs.h
@@ -81,7 +81,7 @@ struct inodes_stat_t {
 #define MS_VERBOSE	32768	/* War is peace. Verbosity is silence.
 				   MS_VERBOSE is deprecated. */
 #define MS_SILENT	32768
-#define MS_POSIXACL	(1<<16)	/* VFS does not apply the umask */
+#define MS_POSIXACL	(1<<16)	/* Supports POSIX ACLs */
 #define MS_UNBINDABLE	(1<<17)	/* change to unbindable */
 #define MS_PRIVATE	(1<<18)	/* change to private */
 #define MS_SLAVE	(1<<19)	/* change to slave */
@@ -91,6 +91,7 @@ struct inodes_stat_t {
 #define MS_I_VERSION	(1<<23) /* Update inode I_version field */
 #define MS_STRICTATIME	(1<<24) /* Always perform atime updates */
 #define MS_LAZYTIME	(1<<25) /* Update the on-disk [acm]times lazily */
+#define MS_RICHACL	(1<<26) /* Supports richacls */
 
 /* These sb flags are internal to the kernel */
 #define MS_NOSEC	(1<<28)
-- 
2.4.3

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#1189935 — [PATCH v5 11/39] vfs: Cache base_acl objects in inodes

From: Andreas Gruenbacher <agruenba@redhat.com>

POSIX ACLs and richacls are both objects allocated by kmalloc() with a
reference count which are freed by kfree_rcu().  An inode can either cache an
access and a default POSIX ACL, or a richacl (richacls do not have default
acls).  To allow an inode to cache either of the two kinds of acls, introduce a
new base_acl type and convert i_acl and i_default_acl to that type. In most
cases, the vfs then doesn't have to care which kind of acl an inode caches (if
any).

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
---
 drivers/staging/lustre/lustre/llite/llite_lib.c |  2 +-
 fs/f2fs/acl.c                                   |  4 ++--
 fs/inode.c                                      |  4 ++--
 fs/posix_acl.c                                  | 18 +++++++++---------
 include/linux/fs.h                              | 25 ++++++++++++++++++++++---
 include/linux/posix_acl.h                       | 12 ++++--------
 include/linux/richacl.h                         |  2 +-
 7 files changed, 41 insertions(+), 26 deletions(-)

diff --git a/drivers/staging/lustre/lustre/llite/llite_lib.c b/drivers/staging/lustre/lustre/llite/llite_lib.c
index 2513988..e198f63 100644
--- a/drivers/staging/lustre/lustre/llite/llite_lib.c
+++ b/drivers/staging/lustre/lustre/llite/llite_lib.c
@@ -1130,7 +1130,7 @@ void ll_clear_inode(struct inode *inode)
 	}
 #ifdef CONFIG_FS_POSIX_ACL
 	else if (lli->lli_posix_acl) {
-		LASSERT(atomic_read(&lli->lli_posix_acl->a_refcount) == 1);
+		LASSERT(atomic_read(&lli->lli_posix_acl->a_base.ba_refcount) == 1);
 		LASSERT(lli->lli_remote_perms == NULL);
 		posix_acl_release(lli->lli_posix_acl);
 		lli->lli_posix_acl = NULL;
diff --git a/fs/f2fs/acl.c b/fs/f2fs/acl.c
index c8f25f7..a4207de 100644
--- a/fs/f2fs/acl.c
+++ b/fs/f2fs/acl.c
@@ -270,7 +270,7 @@ static struct posix_acl *f2fs_acl_clone(const struct posix_acl *acl,
 				sizeof(struct posix_acl_entry);
 		clone = kmemdup(acl, size, flags);
 		if (clone)
-			atomic_set(&clone->a_refcount, 1);
+			atomic_set(&clone->a_base.ba_refcount, 1);
 	}
 	return clone;
 }
@@ -282,7 +282,7 @@ static int f2fs_acl_create_masq(struct posix_acl *acl, umode_t *mode_p)
 	umode_t mode = *mode_p;
 	int not_equiv = 0;
 
-	/* assert(atomic_read(acl->a_refcount) == 1); */
+	/* assert(atomic_read(acl->a_base.ba_refcount) == 1); */
 
 	FOREACH_ACL_ENTRY(pa, acl, pe) {
 		switch(pa->e_tag) {
diff --git a/fs/inode.c b/fs/inode.c
index d30640f..00b442d 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -235,9 +235,9 @@ void __destroy_inode(struct inode *inode)
 
 #ifdef CONFIG_FS_POSIX_ACL
 	if (inode->i_acl && inode->i_acl != ACL_NOT_CACHED)
-		posix_acl_release(inode->i_acl);
+		put_base_acl(inode->i_acl);
 	if (inode->i_default_acl && inode->i_default_acl != ACL_NOT_CACHED)
-		posix_acl_release(inode->i_default_acl);
+		put_base_acl(inode->i_default_acl);
 #endif
 	this_cpu_dec(nr_inodes);
 }
diff --git a/fs/posix_acl.c b/fs/posix_acl.c
index 4fb17de..b3b2265 100644
--- a/fs/posix_acl.c
+++ b/fs/posix_acl.c
@@ -25,9 +25,9 @@ struct posix_acl **acl_by_type(struct inode *inode, int type)
 {
 	switch (type) {
 	case ACL_TYPE_ACCESS:
-		return &inode->i_acl;
+		return (struct posix_acl **)&inode->i_acl;
 	case ACL_TYPE_DEFAULT:
-		return &inode->i_default_acl;
+		return (struct posix_acl **)&inode->i_default_acl;
 	default:
 		BUG();
 	}
@@ -83,16 +83,16 @@ EXPORT_SYMBOL(forget_cached_acl);
 
 void forget_all_cached_acls(struct inode *inode)
 {
-	struct posix_acl *old_access, *old_default;
+	struct base_acl *old_access, *old_default;
 	spin_lock(&inode->i_lock);
 	old_access = inode->i_acl;
 	old_default = inode->i_default_acl;
 	inode->i_acl = inode->i_default_acl = ACL_NOT_CACHED;
 	spin_unlock(&inode->i_lock);
 	if (old_access != ACL_NOT_CACHED)
-		posix_acl_release(old_access);
+		put_base_acl(old_access);
 	if (old_default != ACL_NOT_CACHED)
-		posix_acl_release(old_default);
+		put_base_acl(old_default);
 }
 EXPORT_SYMBOL(forget_all_cached_acls);
 
@@ -129,7 +129,7 @@ EXPORT_SYMBOL(get_acl);
 void
 posix_acl_init(struct posix_acl *acl, int count)
 {
-	atomic_set(&acl->a_refcount, 1);
+	atomic_set(&acl->a_base.ba_refcount, 1);
 	acl->a_count = count;
 }
 EXPORT_SYMBOL(posix_acl_init);
@@ -162,7 +162,7 @@ posix_acl_clone(const struct posix_acl *acl, gfp_t flags)
 		           sizeof(struct posix_acl_entry);
 		clone = kmemdup(acl, size, flags);
 		if (clone)
-			atomic_set(&clone->a_refcount, 1);
+			atomic_set(&clone->a_base.ba_refcount, 1);
 	}
 	return clone;
 }
@@ -384,7 +384,7 @@ static int posix_acl_create_masq(struct posix_acl *acl, umode_t *mode_p)
 	umode_t mode = *mode_p;
 	int not_equiv = 0;
 
-	/* assert(atomic_read(acl->a_refcount) == 1); */
+	/* assert(atomic_read(acl->a_base.ba_refcount) == 1); */
 
 	FOREACH_ACL_ENTRY(pa, acl, pe) {
                 switch(pa->e_tag) {
@@ -439,7 +439,7 @@ static int __posix_acl_chmod_masq(struct posix_acl *acl, umode_t mode)
 	struct posix_acl_entry *group_obj = NULL, *mask_obj = NULL;
 	struct posix_acl_entry *pa, *pe;
 
-	/* assert(atomic_read(acl->a_refcount) == 1); */
+	/* assert(atomic_read(acl->a_base.ba_refcount) == 1); */
 
 	FOREACH_ACL_ENTRY(pa, acl, pe) {
 		switch(pa->e_tag) {
diff --git a/include/linux/fs.h b/include/linux/fs.h
index cfffdaf..cc5c2d1 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -575,6 +575,12 @@ static inline void mapping_allow_writable(struct address_space *mapping)
 #define i_size_ordered_init(inode) do { } while (0)
 #endif
 
+struct base_acl {
+	union {
+		atomic_t ba_refcount;
+		struct rcu_head ba_rcu;
+	};
+};
 struct posix_acl;
 #define ACL_NOT_CACHED ((void *)(-1))
 
@@ -594,9 +600,9 @@ struct inode {
 	kgid_t			i_gid;
 	unsigned int		i_flags;
 
-#ifdef CONFIG_FS_POSIX_ACL
-	struct posix_acl	*i_acl;
-	struct posix_acl	*i_default_acl;
+#if defined(CONFIG_FS_POSIX_ACL)
+	struct base_acl *i_acl;
+	struct base_acl *i_default_acl;
 #endif
 
 	const struct inode_operations	*i_op;
@@ -3059,4 +3065,17 @@ static inline bool dir_relax(struct inode *inode)
 	return !IS_DEADDIR(inode);
 }
 
+static inline struct base_acl *get_base_acl(struct base_acl *acl)
+{
+	if (acl)
+		atomic_inc(&acl->ba_refcount);
+	return acl;
+}
+
+static inline void put_base_acl(struct base_acl *acl)
+{
+	if (acl && atomic_dec_and_test(&acl->ba_refcount))
+		kfree_rcu(acl, ba_rcu);
+}
+
 #endif /* _LINUX_FS_H */
diff --git a/include/linux/posix_acl.h b/include/linux/posix_acl.h
index 3e96a6a..2c46441 100644
--- a/include/linux/posix_acl.h
+++ b/include/linux/posix_acl.h
@@ -43,10 +43,7 @@ struct posix_acl_entry {
 };
 
 struct posix_acl {
-	union {
-		atomic_t		a_refcount;
-		struct rcu_head		a_rcu;
-	};
+	struct base_acl		a_base;
 	unsigned int		a_count;
 	struct posix_acl_entry	a_entries[0];
 };
@@ -61,8 +58,7 @@ struct posix_acl {
 static inline struct posix_acl *
 posix_acl_dup(struct posix_acl *acl)
 {
-	if (acl)
-		atomic_inc(&acl->a_refcount);
+	get_base_acl(&acl->a_base);
 	return acl;
 }
 
@@ -72,8 +68,8 @@ posix_acl_dup(struct posix_acl *acl)
 static inline void
 posix_acl_release(struct posix_acl *acl)
 {
-	if (acl && atomic_dec_and_test(&acl->a_refcount))
-		kfree_rcu(acl, a_rcu);
+	BUILD_BUG_ON(offsetof(struct posix_acl, a_base) != 0);
+	put_base_acl(&acl->a_base);
 }
 
 
diff --git a/include/linux/richacl.h b/include/linux/richacl.h
index 1500824..ce1bb16 100644
--- a/include/linux/richacl.h
+++ b/include/linux/richacl.h
@@ -168,7 +168,7 @@ static inline struct richacl *
 richacl_get(struct richacl *acl)
 {
 	if (acl)
-		atomic_inc(&acl->a_refcount);
+		atomic_inc(&acl->a_base.ba_refcount);
 	return acl;
 }
 
-- 
2.4.3

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#1189936 — [PATCH v5 05/39] vfs: Add permission flags for setting file attributes

From: Andreas Gruenbacher <agruenba@redhat.com>

Richacls support permissions that allow to take ownership of a file, change the
file permissions, and set the file timestamps.  Support that by introducing new
permission mask flags and by checking for those mask flags in
inode_change_ok().

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
---
 fs/attr.c          | 79 +++++++++++++++++++++++++++++++++++++++++++++---------
 include/linux/fs.h |  3 +++
 2 files changed, 70 insertions(+), 12 deletions(-)

diff --git a/fs/attr.c b/fs/attr.c
index 328be71..85483e0 100644
--- a/fs/attr.c
+++ b/fs/attr.c
@@ -17,6 +17,65 @@
 #include <linux/ima.h>
 
 /**
+ * inode_extended_permission  -  permissions beyond read/write/execute
+ *
+ * Check for permissions that only richacls can currently grant.
+ */
+static int inode_extended_permission(struct inode *inode, int mask)
+{
+	if (!IS_RICHACL(inode))
+		return -EPERM;
+	return inode_permission(inode, mask);
+}
+
+static bool inode_uid_change_ok(struct inode *inode, kuid_t ia_uid)
+{
+	if (uid_eq(current_fsuid(), inode->i_uid) &&
+	    uid_eq(ia_uid, inode->i_uid))
+		return true;
+	if (uid_eq(current_fsuid(), ia_uid) &&
+	    inode_extended_permission(inode, MAY_TAKE_OWNERSHIP) == 0)
+		return true;
+	if (capable_wrt_inode_uidgid(inode, CAP_CHOWN))
+		return true;
+	return false;
+}
+
+static bool inode_gid_change_ok(struct inode *inode, kgid_t ia_gid)
+{
+	int in_group = in_group_p(ia_gid);
+	if (uid_eq(current_fsuid(), inode->i_uid) &&
+	    (in_group || gid_eq(ia_gid, inode->i_gid)))
+		return true;
+	if (in_group && inode_extended_permission(inode, MAY_TAKE_OWNERSHIP) == 0)
+		return true;
+	if (capable_wrt_inode_uidgid(inode, CAP_CHOWN))
+		return true;
+	return false;
+}
+
+/**
+ * inode_owner_permitted_or_capable
+ *
+ * Check for permissions implicitly granted to the owner, like MAY_CHMOD or
+ * MAY_SET_TIMES.  Equivalent to inode_owner_or_capable for file systems
+ * without support for those permissions.
+ */
+static bool inode_owner_permitted_or_capable(struct inode *inode, int mask)
+{
+	struct user_namespace *ns;
+
+	if (uid_eq(current_fsuid(), inode->i_uid))
+		return true;
+	if (inode_extended_permission(inode, mask) == 0)
+		return true;
+	ns = current_user_ns();
+	if (ns_capable(ns, CAP_FOWNER) && kuid_has_mapping(ns, inode->i_uid))
+		return true;
+	return false;
+}
+
+/**
  * inode_change_ok - check if attribute changes to an inode are allowed
  * @inode:	inode to check
  * @attr:	attributes to change
@@ -47,22 +106,18 @@ int inode_change_ok(struct inode *inode, struct iattr *attr)
 		return 0;
 
 	/* Make sure a caller can chown. */
-	if ((ia_valid & ATTR_UID) &&
-	    (!uid_eq(current_fsuid(), inode->i_uid) ||
-	     !uid_eq(attr->ia_uid, inode->i_uid)) &&
-	    !capable_wrt_inode_uidgid(inode, CAP_CHOWN))
-		return -EPERM;
+	if (ia_valid & ATTR_UID)
+		if (!inode_uid_change_ok(inode, attr->ia_uid))
+			return -EPERM;
 
 	/* Make sure caller can chgrp. */
-	if ((ia_valid & ATTR_GID) &&
-	    (!uid_eq(current_fsuid(), inode->i_uid) ||
-	    (!in_group_p(attr->ia_gid) && !gid_eq(attr->ia_gid, inode->i_gid))) &&
-	    !capable_wrt_inode_uidgid(inode, CAP_CHOWN))
-		return -EPERM;
+	if (ia_valid & ATTR_GID)
+		if (!inode_gid_change_ok(inode, attr->ia_gid))
+			return -EPERM;
 
 	/* Make sure a caller can chmod. */
 	if (ia_valid & ATTR_MODE) {
-		if (!inode_owner_or_capable(inode))
+		if (!inode_owner_permitted_or_capable(inode, MAY_CHMOD))
 			return -EPERM;
 		/* Also check the setgid bit! */
 		if (!in_group_p((ia_valid & ATTR_GID) ? attr->ia_gid :
@@ -73,7 +128,7 @@ int inode_change_ok(struct inode *inode, struct iattr *attr)
 
 	/* Check for setting the inode time. */
 	if (ia_valid & (ATTR_MTIME_SET | ATTR_ATIME_SET | ATTR_TIMES_SET)) {
-		if (!inode_owner_or_capable(inode))
+		if (!inode_owner_permitted_or_capable(inode, MAY_SET_TIMES))
 			return -EPERM;
 	}
 
diff --git a/include/linux/fs.h b/include/linux/fs.h
index aae46e0..cfffdaf 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -85,6 +85,9 @@ typedef void (dax_iodone_t)(struct buffer_head *bh_map, int uptodate);
 #define MAY_CREATE_DIR		0x00000200
 #define MAY_DELETE_CHILD	0x00000400
 #define MAY_DELETE_SELF		0x00000800
+#define MAY_TAKE_OWNERSHIP	0x00001000
+#define MAY_CHMOD		0x00002000
+#define MAY_SET_TIMES		0x00004000
 
 /*
  * flags in file.f_mode.  Note that FMODE_READ and FMODE_WRITE must correspond
-- 
2.4.3

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#1189937 — [PATCH v5 12/39] vfs: Cache richacl in struct inode

From: Andreas Gruenbacher <agruenba@redhat.com>

Cache richacls in struct inode so that this doesn't have to be done
individually in each filesystem.  This is similar to POSIX ACLs.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
---
 fs/inode.c              | 11 ++++++--
 fs/posix_acl.c          |  2 +-
 fs/richacl_base.c       |  4 +--
 fs/richacl_inode.c      | 73 +++++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/fs.h      |  6 +++-
 include/linux/richacl.h | 15 ++++++----
 6 files changed, 99 insertions(+), 12 deletions(-)

diff --git a/fs/inode.c b/fs/inode.c
index 00b442d..3bcd7ee 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -176,8 +176,11 @@ int inode_init_always(struct super_block *sb, struct inode *inode)
 	inode->i_private = NULL;
 	inode->i_mapping = mapping;
 	INIT_HLIST_HEAD(&inode->i_dentry);	/* buggered by rcu freeing */
-#ifdef CONFIG_FS_POSIX_ACL
-	inode->i_acl = inode->i_default_acl = ACL_NOT_CACHED;
+#if defined(CONFIG_FS_POSIX_ACL) || defined(CONFIG_FS_RICHACL)
+	inode->i_acl = ACL_NOT_CACHED;
+# if defined(CONFIG_FS_POSIX_ACL)
+	inode->i_default_acl = ACL_NOT_CACHED;
+# endif
 #endif
 
 #ifdef CONFIG_FSNOTIFY
@@ -233,11 +236,13 @@ void __destroy_inode(struct inode *inode)
 		atomic_long_dec(&inode->i_sb->s_remove_count);
 	}
 
-#ifdef CONFIG_FS_POSIX_ACL
+#if defined(CONFIG_FS_POSIX_ACL) || defined(CONFIG_FS_RICHACL)
 	if (inode->i_acl && inode->i_acl != ACL_NOT_CACHED)
 		put_base_acl(inode->i_acl);
+# if defined(CONFIG_FS_POSIX_ACL)
 	if (inode->i_default_acl && inode->i_default_acl != ACL_NOT_CACHED)
 		put_base_acl(inode->i_default_acl);
+# endif
 #endif
 	this_cpu_dec(nr_inodes);
 }
diff --git a/fs/posix_acl.c b/fs/posix_acl.c
index b3b2265..1d766a5 100644
--- a/fs/posix_acl.c
+++ b/fs/posix_acl.c
@@ -38,7 +38,7 @@ struct posix_acl *get_cached_acl(struct inode *inode, int type)
 {
 	struct posix_acl **p = acl_by_type(inode, type);
 	struct posix_acl *acl = ACCESS_ONCE(*p);
-	if (acl) {
+	if (acl && IS_POSIXACL(inode)) {
 		spin_lock(&inode->i_lock);
 		acl = *p;
 		if (acl != ACL_NOT_CACHED)
diff --git a/fs/richacl_base.c b/fs/richacl_base.c
index e88cdda..3c13535 100644
--- a/fs/richacl_base.c
+++ b/fs/richacl_base.c
@@ -33,7 +33,7 @@ richacl_alloc(int count, gfp_t gfp)
 	struct richacl *acl = kzalloc(size, gfp);
 
 	if (acl) {
-		atomic_set(&acl->a_refcount, 1);
+		atomic_set(&acl->a_base.ba_refcount, 1);
 		acl->a_count = count;
 	}
 	return acl;
@@ -52,7 +52,7 @@ richacl_clone(const struct richacl *acl, gfp_t gfp)
 
 	if (dup) {
 		memcpy(dup, acl, size);
-		atomic_set(&dup->a_refcount, 1);
+		atomic_set(&dup->a_base.ba_refcount, 1);
 	}
 	return dup;
 }
diff --git a/fs/richacl_inode.c b/fs/richacl_inode.c
index 63f3b87..72c461d 100644
--- a/fs/richacl_inode.c
+++ b/fs/richacl_inode.c
@@ -20,6 +20,79 @@
 #include <linux/slab.h>
 #include <linux/richacl.h>
 
+struct richacl *get_cached_richacl(struct inode *inode)
+{
+	struct richacl *acl;
+
+	acl = (struct richacl *)ACCESS_ONCE(inode->i_acl);
+	if (acl && IS_RICHACL(inode)) {
+		spin_lock(&inode->i_lock);
+		acl = (struct richacl *)inode->i_acl;
+		if (acl != ACL_NOT_CACHED)
+			acl = richacl_get(acl);
+		spin_unlock(&inode->i_lock);
+	}
+	return acl;
+}
+EXPORT_SYMBOL_GPL(get_cached_richacl);
+
+struct richacl *get_cached_richacl_rcu(struct inode *inode)
+{
+	return (struct richacl *)rcu_dereference(inode->i_acl);
+}
+EXPORT_SYMBOL_GPL(get_cached_richacl_rcu);
+
+void set_cached_richacl(struct inode *inode, struct richacl *acl)
+{
+	struct base_acl *old = NULL;
+	spin_lock(&inode->i_lock);
+	old = inode->i_acl;
+	rcu_assign_pointer(inode->i_acl, &richacl_get(acl)->a_base);
+	spin_unlock(&inode->i_lock);
+	if (old != ACL_NOT_CACHED)
+		put_base_acl(old);
+}
+EXPORT_SYMBOL_GPL(set_cached_richacl);
+
+void forget_cached_richacl(struct inode *inode)
+{
+	struct base_acl *old = NULL;
+	spin_lock(&inode->i_lock);
+	old = inode->i_acl;
+	inode->i_acl = ACL_NOT_CACHED;
+	spin_unlock(&inode->i_lock);
+	if (old != ACL_NOT_CACHED)
+		put_base_acl(old);
+}
+EXPORT_SYMBOL_GPL(forget_cached_richacl);
+
+struct richacl *get_richacl(struct inode *inode)
+{
+	struct richacl *acl;
+
+	acl = get_cached_richacl(inode);
+	if (acl != ACL_NOT_CACHED)
+		return acl;
+
+	if (!IS_RICHACL(inode))
+		return NULL;
+
+	/*
+	 * A filesystem can force a ACL callback by just never filling the
+	 * ACL cache. But normally you'd fill the cache either at inode
+	 * instantiation time, or on the first ->get_richacl call.
+	 *
+	 * If the filesystem doesn't have a get_richacl() function at all,
+	 * we'll just create the negative cache entry.
+	 */
+	if (!inode->i_op->get_richacl) {
+		set_cached_richacl(inode, NULL);
+		return NULL;
+	}
+	return inode->i_op->get_richacl(inode);
+}
+EXPORT_SYMBOL_GPL(get_richacl);
+
 /**
  * richacl_permission  -  richacl permission check algorithm
  * @inode:	inode to check
diff --git a/include/linux/fs.h b/include/linux/fs.h
index cc5c2d1..00abca5 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -582,6 +582,7 @@ struct base_acl {
 	};
 };
 struct posix_acl;
+struct richacl;
 #define ACL_NOT_CACHED ((void *)(-1))
 
 #define IOP_FASTPERM	0x0001
@@ -600,9 +601,11 @@ struct inode {
 	kgid_t			i_gid;
 	unsigned int		i_flags;
 
-#if defined(CONFIG_FS_POSIX_ACL)
+#if defined(CONFIG_FS_POSIX_ACL) || defined(CONFIG_FS_RICHACL)
 	struct base_acl *i_acl;
+# if defined(CONFIG_FS_POSIX_ACL)
 	struct base_acl *i_default_acl;
+# endif
 #endif
 
 	const struct inode_operations	*i_op;
@@ -1651,6 +1654,7 @@ struct inode_operations {
 	const char * (*follow_link) (struct dentry *, void **);
 	int (*permission) (struct inode *, int);
 	struct posix_acl * (*get_acl)(struct inode *, int);
+	struct richacl * (*get_richacl)(struct inode *);
 
 	int (*readlink) (struct dentry *, char __user *,int);
 	void (*put_link) (struct inode *, void *);
diff --git a/include/linux/richacl.h b/include/linux/richacl.h
index ce1bb16..f59ffa73 100644
--- a/include/linux/richacl.h
+++ b/include/linux/richacl.h
@@ -33,7 +33,7 @@ struct richace {
 };
 
 struct richacl {
-	atomic_t	a_refcount;
+	struct base_acl	a_base;
 	unsigned int	a_owner_mask;
 	unsigned int	a_group_mask;
 	unsigned int	a_other_mask;
@@ -167,8 +167,7 @@ struct richacl {
 static inline struct richacl *
 richacl_get(struct richacl *acl)
 {
-	if (acl)
-		atomic_inc(&acl->a_base.ba_refcount);
+	get_base_acl(&acl->a_base);
 	return acl;
 }
 
@@ -178,10 +177,16 @@ richacl_get(struct richacl *acl)
 static inline void
 richacl_put(struct richacl *acl)
 {
-	if (acl && atomic_dec_and_test(&acl->a_refcount))
-		kfree(acl);
+	BUILD_BUG_ON(offsetof(struct richacl, a_base) != 0);
+	put_base_acl(&acl->a_base);
 }
 
+extern struct richacl *get_cached_richacl(struct inode *);
+extern struct richacl *get_cached_richacl_rcu(struct inode *);
+extern void set_cached_richacl(struct inode *, struct richacl *);
+extern void forget_cached_richacl(struct inode *);
+extern struct richacl *get_richacl(struct inode *);
+
 /**
  * richace_is_owner  -  check if @ace is an OWNER@ entry
  */
-- 
2.4.3

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#1189939 — [PATCH v5 07/39] richacl: Permission mapping functions

From: Andreas Gruenbacher <agruenba@redhat.com>

We need to map from POSIX permissions to NFSv4 permissions when a
chmod() is done, from NFSv4 permissions to POSIX permissions when an acl
is set (which implicitly sets the file permission bits), and from the
MAY_READ/MAY_WRITE/MAY_EXEC/MAY_APPEND flags to NFSv4 permissions when
doing an access check in a richacl.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
---
 fs/richacl_base.c       | 113 ++++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/richacl.h |  47 +++++++++++++++++++-
 2 files changed, 159 insertions(+), 1 deletion(-)

diff --git a/fs/richacl_base.c b/fs/richacl_base.c
index 6d9a073..d12f984 100644
--- a/fs/richacl_base.c
+++ b/fs/richacl_base.c
@@ -65,3 +65,116 @@ richace_copy(struct richace *to, const struct richace *from)
 {
 	memcpy(to, from, sizeof(struct richace));
 }
+
+/*
+ * richacl_mask_to_mode  -  compute the file permission bits which correspond to @mask
+ * @mask:	%RICHACE_* permission mask
+ *
+ * See richacl_masks_to_mode().
+ */
+static int
+richacl_mask_to_mode(unsigned int mask)
+{
+	int mode = 0;
+
+	if (mask & RICHACE_POSIX_MODE_READ)
+		mode |= S_IROTH;
+	if (mask & RICHACE_POSIX_MODE_WRITE)
+		mode |= S_IWOTH;
+	if (mask & RICHACE_POSIX_MODE_EXEC)
+		mode |= S_IXOTH;
+
+	return mode;
+}
+
+/**
+ * richacl_masks_to_mode  -  compute the file permission bits from the file masks
+ *
+ * When setting a richacl, we set the file permission bits to indicate maximum
+ * permissions: for example, we set the Write permission when a mask contains
+ * RICHACE_APPEND_DATA even if it does not also contain RICHACE_WRITE_DATA.
+ *
+ * Permissions which are not in RICHACE_POSIX_MODE_READ, RICHACE_POSIX_MODE_WRITE, or
+ * RICHACE_POSIX_MODE_EXEC cannot be represented in the file permission bits.
+ * Such permissions can still be effective, but not for new files or after a
+ * chmod(); they must be explicitly enabled in the richacl.
+ */
+int
+richacl_masks_to_mode(const struct richacl *acl)
+{
+	return richacl_mask_to_mode(acl->a_owner_mask) << 6 |
+	       richacl_mask_to_mode(acl->a_group_mask) << 3 |
+	       richacl_mask_to_mode(acl->a_other_mask);
+}
+EXPORT_SYMBOL_GPL(richacl_masks_to_mode);
+
+/**
+ * richacl_mode_to_mask  - compute a file mask from the lowest three mode bits
+ *
+ * When the file permission bits of a file are set with chmod(), this specifies
+ * the maximum permissions that processes will get.  All permissions beyond
+ * that will be removed from the file masks, and become ineffective.
+ */
+unsigned int
+richacl_mode_to_mask(mode_t mode)
+{
+	unsigned int mask = 0;
+
+	if (mode & S_IROTH)
+		mask |= RICHACE_POSIX_MODE_READ;
+	if (mode & S_IWOTH)
+		mask |= RICHACE_POSIX_MODE_WRITE;
+	if (mode & S_IXOTH)
+		mask |= RICHACE_POSIX_MODE_EXEC;
+
+	return mask;
+}
+
+/**
+ * richacl_want_to_mask  - convert the iop->permission want argument to a mask
+ * @want:	@want argument of the permission inode operation
+ *
+ * When checking for append, @want is (MAY_WRITE | MAY_APPEND).
+ *
+ * Richacls use the iop->may_create and iop->may_delete hooks which are
+ * used for checking if creating and deleting files is allowed.  These hooks do
+ * not use richacl_want_to_mask(), so we do not have to deal with mapping
+ * MAY_WRITE to RICHACE_ADD_FILE, RICHACE_ADD_SUBDIRECTORY, and RICHACE_DELETE_CHILD
+ * here.
+ */
+unsigned int
+richacl_want_to_mask(unsigned int want)
+{
+	unsigned int mask = 0;
+
+	if (want & MAY_READ)
+		mask |= RICHACE_READ_DATA;
+	if (want & MAY_DELETE_SELF)
+		mask |= RICHACE_DELETE;
+	if (want & MAY_TAKE_OWNERSHIP)
+		mask |= RICHACE_WRITE_OWNER;
+	if (want & MAY_CHMOD)
+		mask |= RICHACE_WRITE_ACL;
+	if (want & MAY_SET_TIMES)
+		mask |= RICHACE_WRITE_ATTRIBUTES;
+	if (want & MAY_EXEC)
+		mask |= RICHACE_EXECUTE;
+	/*
+	 * differentiate MAY_WRITE from these request
+	 */
+	if (want & (MAY_APPEND |
+		    MAY_CREATE_FILE | MAY_CREATE_DIR |
+		    MAY_DELETE_CHILD)) {
+		if (want & MAY_APPEND)
+			mask |= RICHACE_APPEND_DATA;
+		if (want & MAY_CREATE_FILE)
+			mask |= RICHACE_ADD_FILE;
+		if (want & MAY_CREATE_DIR)
+			mask |= RICHACE_ADD_SUBDIRECTORY;
+		if (want & MAY_DELETE_CHILD)
+			mask |= RICHACE_DELETE_CHILD;
+	} else if (want & MAY_WRITE)
+		mask |= RICHACE_WRITE_DATA;
+	return mask;
+}
+EXPORT_SYMBOL_GPL(richacl_want_to_mask);
diff --git a/include/linux/richacl.h b/include/linux/richacl.h
index 060d5e4..1ae0bf8 100644
--- a/include/linux/richacl.h
+++ b/include/linux/richacl.h
@@ -118,6 +118,49 @@ struct richacl {
 	RICHACE_WRITE_OWNER |					\
 	RICHACE_SYNCHRONIZE)
 
+/*
+ * The POSIX permissions are supersets of the following NFSv4 permissions:
+ *
+ *  - MAY_READ maps to READ_DATA or LIST_DIRECTORY, depending on the type
+ *    of the file system object.
+ *
+ *  - MAY_WRITE maps to WRITE_DATA or RICHACE_APPEND_DATA for files, and to
+ *    ADD_FILE, RICHACE_ADD_SUBDIRECTORY, or RICHACE_DELETE_CHILD for directories.
+ *
+ *  - MAY_EXECUTE maps to RICHACE_EXECUTE.
+ *
+ *  (Some of these NFSv4 permissions have the same bit values.)
+ */
+#define RICHACE_POSIX_MODE_READ (			\
+		RICHACE_READ_DATA |		\
+		RICHACE_LIST_DIRECTORY)
+#define RICHACE_POSIX_MODE_WRITE (			\
+		RICHACE_WRITE_DATA |		\
+		RICHACE_ADD_FILE |			\
+		RICHACE_APPEND_DATA |		\
+		RICHACE_ADD_SUBDIRECTORY |		\
+		RICHACE_DELETE_CHILD)
+#define RICHACE_POSIX_MODE_EXEC RICHACE_EXECUTE
+#define RICHACE_POSIX_MODE_ALL (			\
+		RICHACE_POSIX_MODE_READ |		\
+		RICHACE_POSIX_MODE_WRITE |		\
+		RICHACE_POSIX_MODE_EXEC)
+/*
+ * These permissions are always allowed
+ * no matter what the acl says.
+ */
+#define RICHACE_POSIX_ALWAYS_ALLOWED (	\
+		RICHACE_SYNCHRONIZE |	\
+		RICHACE_READ_ATTRIBUTES |	\
+		RICHACE_READ_ACL)
+/*
+ * The owner is implicitly granted
+ * these permissions under POSIX.
+ */
+#define RICHACE_POSIX_OWNER_ALLOWED (		\
+		RICHACE_WRITE_ATTRIBUTES |		\
+		RICHACE_WRITE_OWNER |		\
+		RICHACE_WRITE_ACL)
 /**
  * richacl_get  -  grab another reference to a richacl handle
  */
@@ -255,6 +298,8 @@ richace_is_same_identifier(const struct richace *a, const struct richace *b)
 extern struct richacl *richacl_alloc(int, gfp_t);
 extern struct richacl *richacl_clone(const struct richacl *, gfp_t);
 extern void richace_copy(struct richace *, const struct richace *);
-
+extern int richacl_masks_to_mode(const struct richacl *);
+extern unsigned int richacl_mode_to_mask(mode_t);
+extern unsigned int richacl_want_to_mask(unsigned int);
 
 #endif /* __RICHACL_H */
-- 
2.4.3

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#1189940 — [PATCH v5 04/39] vfs: Make the inode passed to inode_change_ok non-const

From: Andreas Gruenbacher <agruenba@redhat.com>

We will need to call iop->permission and iop->get_acl from
inode_change_ok() for additional permission checks, and both take a
non-const inode.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
---
 fs/attr.c          | 2 +-
 include/linux/fs.h | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/attr.c b/fs/attr.c
index 6530ced..328be71 100644
--- a/fs/attr.c
+++ b/fs/attr.c
@@ -28,7 +28,7 @@
  * Should be called as the first thing in ->setattr implementations,
  * possibly after taking additional locks.
  */
-int inode_change_ok(const struct inode *inode, struct iattr *attr)
+int inode_change_ok(struct inode *inode, struct iattr *attr)
 {
 	unsigned int ia_valid = attr->ia_valid;
 
diff --git a/include/linux/fs.h b/include/linux/fs.h
index abf5b0e..aae46e0 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2873,7 +2873,7 @@ extern int buffer_migrate_page(struct address_space *,
 #define buffer_migrate_page NULL
 #endif
 
-extern int inode_change_ok(const struct inode *, struct iattr *);
+extern int inode_change_ok(struct inode *, struct iattr *);
 extern int inode_newsize_ok(const struct inode *, loff_t offset);
 extern void setattr_copy(struct inode *inode, const struct iattr *attr);
 
-- 
2.4.3

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#1189943 — [PATCH v5 16/39] richacl: xattr mapping functions

From: Andreas Gruenbacher <agruenba@redhat.com>

Map between "system.richacl" xattrs and the in-kernel representation.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
---
 fs/Makefile                   |   2 +-
 fs/richacl_xattr.c            | 209 ++++++++++++++++++++++++++++++++++++++++++
 fs/xattr.c                    |  34 +++++--
 include/linux/richacl_xattr.h |  52 +++++++++++
 include/uapi/linux/xattr.h    |   2 +
 5 files changed, 292 insertions(+), 7 deletions(-)
 create mode 100644 fs/richacl_xattr.c
 create mode 100644 include/linux/richacl_xattr.h

diff --git a/fs/Makefile b/fs/Makefile
index 1305047..baf385a 100644
--- a/fs/Makefile
+++ b/fs/Makefile
@@ -48,7 +48,7 @@ obj-$(CONFIG_SYSCTL)		+= drop_caches.o
 
 obj-$(CONFIG_FHANDLE)		+= fhandle.o
 obj-$(CONFIG_FS_RICHACL)	+= richacl.o
-richacl-y			:= richacl_base.o richacl_inode.o
+richacl-y			:= richacl_base.o richacl_inode.o richacl_xattr.o
 
 obj-y				+= quota/
 
diff --git a/fs/richacl_xattr.c b/fs/richacl_xattr.c
new file mode 100644
index 0000000..d145915
--- /dev/null
+++ b/fs/richacl_xattr.c
@@ -0,0 +1,209 @@
+/*
+ * Copyright (C) 2006, 2010  Novell, Inc.
+ * Copyright (C) 2015  Red Hat, Inc.
+ * Written by Andreas Gruenbacher <agruen@kernel.org>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2, or (at your option) any
+ * later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ */
+
+#include <linux/sched.h>
+#include <linux/fs.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/richacl_xattr.h>
+
+MODULE_LICENSE("GPL");
+
+/**
+ * richacl_from_xattr  -  convert a richacl xattr into the in-memory representation
+ */
+struct richacl *
+richacl_from_xattr(struct user_namespace *user_ns,
+		   const void *value, size_t size)
+{
+	const struct richacl_xattr *xattr_acl = value;
+	const struct richace_xattr *xattr_ace = (void *)(xattr_acl + 1);
+	struct richacl *acl;
+	struct richace *ace;
+	int count;
+
+	if (size < sizeof(*xattr_acl) ||
+	    xattr_acl->a_version != RICHACL_XATTR_VERSION ||
+	    (xattr_acl->a_flags & ~RICHACL_VALID_FLAGS))
+		return ERR_PTR(-EINVAL);
+	size -= sizeof(*xattr_acl);
+	count = le16_to_cpu(xattr_acl->a_count);
+	if (count > RICHACL_XATTR_MAX_COUNT)
+		return ERR_PTR(-EINVAL);
+	if (size != count * sizeof(*xattr_ace))
+		return ERR_PTR(-EINVAL);
+
+	acl = richacl_alloc(count, GFP_NOFS);
+	if (!acl)
+		return ERR_PTR(-ENOMEM);
+
+	acl->a_flags = xattr_acl->a_flags;
+	acl->a_owner_mask = le32_to_cpu(xattr_acl->a_owner_mask);
+	if (acl->a_owner_mask & ~RICHACE_VALID_MASK)
+		goto fail_einval;
+	acl->a_group_mask = le32_to_cpu(xattr_acl->a_group_mask);
+	if (acl->a_group_mask & ~RICHACE_VALID_MASK)
+		goto fail_einval;
+	acl->a_other_mask = le32_to_cpu(xattr_acl->a_other_mask);
+	if (acl->a_other_mask & ~RICHACE_VALID_MASK)
+		goto fail_einval;
+
+	richacl_for_each_entry(ace, acl) {
+		ace->e_type  = le16_to_cpu(xattr_ace->e_type);
+		ace->e_flags = le16_to_cpu(xattr_ace->e_flags);
+		ace->e_mask  = le32_to_cpu(xattr_ace->e_mask);
+
+		if (ace->e_flags & ~RICHACE_VALID_FLAGS)
+			goto fail_einval;
+		if (ace->e_flags & RICHACE_SPECIAL_WHO) {
+			ace->e_id.special = le32_to_cpu(xattr_ace->e_id);
+			if (ace->e_id.special > RICHACE_EVERYONE_SPECIAL_ID)
+				goto fail_einval;
+		} else if (ace->e_flags & RICHACE_IDENTIFIER_GROUP) {
+			ace->e_id.gid = make_kgid(user_ns, le32_to_cpu(xattr_ace->e_id));
+			if (!gid_valid(ace->e_id.gid))
+				goto fail_einval;
+		} else {
+			ace->e_id.uid = make_kuid(user_ns, le32_to_cpu(xattr_ace->e_id));
+			if (!uid_valid(ace->e_id.uid))
+				goto fail_einval;
+		}
+		if (ace->e_type > RICHACE_ACCESS_DENIED_ACE_TYPE ||
+		    (ace->e_mask & ~RICHACE_VALID_MASK))
+			goto fail_einval;
+
+		xattr_ace++;
+	}
+
+	return acl;
+
+fail_einval:
+	richacl_put(acl);
+	return ERR_PTR(-EINVAL);
+}
+EXPORT_SYMBOL_GPL(richacl_from_xattr);
+
+/**
+ * richacl_xattr_size  -  compute the size of the xattr representation of @acl
+ */
+size_t
+richacl_xattr_size(const struct richacl *acl)
+{
+	size_t size = sizeof(struct richacl_xattr);
+
+	size += sizeof(struct richace_xattr) * acl->a_count;
+	return size;
+}
+EXPORT_SYMBOL_GPL(richacl_xattr_size);
+
+/**
+ * richacl_to_xattr  -  convert @acl into its xattr representation
+ * @acl:	the richacl to convert
+ * @buffer:	buffer for the result
+ * @size:	size of @buffer
+ */
+int
+richacl_to_xattr(struct user_namespace *user_ns,
+		 const struct richacl *acl, void *buffer, size_t size)
+{
+	struct richacl_xattr *xattr_acl = buffer;
+	struct richace_xattr *xattr_ace;
+	const struct richace *ace;
+	size_t real_size;
+
+	real_size = richacl_xattr_size(acl);
+	if (!buffer)
+		return real_size;
+	if (real_size > size)
+		return -ERANGE;
+
+	xattr_acl->a_version = RICHACL_XATTR_VERSION;
+	xattr_acl->a_flags = acl->a_flags;
+	xattr_acl->a_count = cpu_to_le16(acl->a_count);
+
+	xattr_acl->a_owner_mask = cpu_to_le32(acl->a_owner_mask);
+	xattr_acl->a_group_mask = cpu_to_le32(acl->a_group_mask);
+	xattr_acl->a_other_mask = cpu_to_le32(acl->a_other_mask);
+
+	xattr_ace = (void *)(xattr_acl + 1);
+	richacl_for_each_entry(ace, acl) {
+		xattr_ace->e_type = cpu_to_le16(ace->e_type);
+		xattr_ace->e_flags = cpu_to_le16(ace->e_flags);
+		xattr_ace->e_mask = cpu_to_le32(ace->e_mask);
+		if (ace->e_flags & RICHACE_SPECIAL_WHO)
+			xattr_ace->e_id = cpu_to_le32(ace->e_id.special);
+		else if (ace->e_flags & RICHACE_IDENTIFIER_GROUP)
+			xattr_ace->e_id =
+				cpu_to_le32(from_kgid(user_ns, ace->e_id.gid));
+		else
+			xattr_ace->e_id =
+				cpu_to_le32(from_kuid(user_ns, ace->e_id.uid));
+		xattr_ace++;
+	}
+	return real_size;
+}
+EXPORT_SYMBOL_GPL(richacl_to_xattr);
+
+/*
+ * Fix up the uids and gids in richacl extended attributes in place.
+ */
+static void richacl_fix_xattr_userns(
+	struct user_namespace *to, struct user_namespace *from,
+	void *value, size_t size)
+{
+	struct richacl_xattr *xattr_acl = value;
+	struct richace_xattr *xattr_ace =
+		(struct richace_xattr *)(xattr_acl + 1);
+	unsigned int count;
+
+	if (!value)
+		return;
+	if (size < sizeof(*xattr_acl))
+		return;
+	if (xattr_acl->a_version != cpu_to_le32(RICHACL_XATTR_VERSION))
+		return;
+	size -= sizeof(*xattr_acl);
+	if (size % sizeof(*xattr_ace))
+		return;
+	count = size / sizeof(*xattr_ace);
+	for (; count; count--, xattr_ace++) {
+		if (xattr_ace->e_flags & cpu_to_le16(RICHACE_SPECIAL_WHO))
+			continue;
+		if (xattr_ace->e_flags & cpu_to_le16(RICHACE_IDENTIFIER_GROUP)) {
+			kgid_t gid = make_kgid(from, le32_to_cpu(xattr_ace->e_id));
+			xattr_ace->e_id = cpu_to_le32(from_kgid(to, gid));
+		} else {
+			kuid_t uid = make_kuid(from, le32_to_cpu(xattr_ace->e_id));
+			xattr_ace->e_id = cpu_to_le32(from_kuid(to, uid));
+		}
+	}
+}
+
+void richacl_fix_xattr_from_user(void *value, size_t size)
+{
+	struct user_namespace *user_ns = current_user_ns();
+	if (user_ns == &init_user_ns)
+		return;
+	richacl_fix_xattr_userns(&init_user_ns, user_ns, value, size);
+}
+
+void richacl_fix_xattr_to_user(void *value, size_t size)
+{
+	struct user_namespace *user_ns = current_user_ns();
+	if (user_ns == &init_user_ns)
+		return;
+	richacl_fix_xattr_userns(user_ns, &init_user_ns, value, size);
+}
diff --git a/fs/xattr.c b/fs/xattr.c
index 072fee1..f2313c6 100644
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -21,6 +21,7 @@
 #include <linux/audit.h>
 #include <linux/vmalloc.h>
 #include <linux/posix_acl_xattr.h>
+#include <linux/richacl_xattr.h>
 
 #include <asm/uaccess.h>
 
@@ -314,6 +315,18 @@ out:
 }
 EXPORT_SYMBOL_GPL(vfs_removexattr);
 
+static void
+fix_xattr_from_user(const char *kname, void *kvalue, size_t size)
+{
+	if (strncmp(kname, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
+		return;
+	kname += XATTR_SYSTEM_PREFIX_LEN;
+	if (!strcmp(kname, XATTR_POSIX_ACL_ACCESS) ||
+	    !strcmp(kname, XATTR_POSIX_ACL_DEFAULT))
+		posix_acl_fix_xattr_from_user(kvalue, size);
+	else if (!strcmp(kname, XATTR_RICHACL))
+		richacl_fix_xattr_from_user(kvalue, size);
+}
 
 /*
  * Extended attribute SET operations
@@ -350,9 +363,7 @@ setxattr(struct dentry *d, const char __user *name, const void __user *value,
 			error = -EFAULT;
 			goto out;
 		}
-		if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) ||
-		    (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0))
-			posix_acl_fix_xattr_from_user(kvalue, size);
+		fix_xattr_from_user(kname, kvalue, size);
 	}
 
 	error = vfs_setxattr(d, kname, kvalue, size, flags);
@@ -419,6 +430,19 @@ SYSCALL_DEFINE5(fsetxattr, int, fd, const char __user *, name,
 	return error;
 }
 
+static void
+fix_xattr_to_user(const char *kname, void *kvalue, size_t size)
+{
+	if (strncmp(kname, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
+		return;
+	kname += XATTR_SYSTEM_PREFIX_LEN;
+	if (!strcmp(kname, XATTR_POSIX_ACL_ACCESS) ||
+	    !strcmp(kname, XATTR_POSIX_ACL_DEFAULT))
+		posix_acl_fix_xattr_to_user(kvalue, size);
+	else if (!strcmp(kname, XATTR_RICHACL))
+		richacl_fix_xattr_to_user(kvalue, size);
+}
+
 /*
  * Extended attribute GET operations
  */
@@ -451,9 +475,7 @@ getxattr(struct dentry *d, const char __user *name, void __user *value,
 
 	error = vfs_getxattr(d, kname, kvalue, size);
 	if (error > 0) {
-		if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) ||
-		    (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0))
-			posix_acl_fix_xattr_to_user(kvalue, size);
+		fix_xattr_to_user(kname, kvalue, size);
 		if (size && copy_to_user(value, kvalue, error))
 			error = -EFAULT;
 	} else if (error == -ERANGE && size >= XATTR_SIZE_MAX) {
diff --git a/include/linux/richacl_xattr.h b/include/linux/richacl_xattr.h
new file mode 100644
index 0000000..1f75959
--- /dev/null
+++ b/include/linux/richacl_xattr.h
@@ -0,0 +1,52 @@
+/*
+ * Copyright (C) 2006, 2010  Novell, Inc.
+ * Copyright (C) 2015  Red Hat, Inc.
+ * Written by Andreas Gruenbacher <agruen@kernel.org>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2, or (at your option) any
+ * later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ */
+
+#ifndef __RICHACL_XATTR_H
+#define __RICHACL_XATTR_H
+
+#include <linux/richacl.h>
+
+#define RICHACL_XATTR "system.richacl"
+
+struct richace_xattr {
+	__le16		e_type;
+	__le16		e_flags;
+	__le32		e_mask;
+	__le32		e_id;
+};
+
+struct richacl_xattr {
+	unsigned char	a_version;
+	unsigned char	a_flags;
+	__le16		a_count;
+	__le32		a_owner_mask;
+	__le32		a_group_mask;
+	__le32		a_other_mask;
+};
+
+#define RICHACL_XATTR_VERSION	0
+#define RICHACL_XATTR_MAX_COUNT \
+	((XATTR_SIZE_MAX - sizeof(struct richacl_xattr)) / \
+	 sizeof(struct richace_xattr))
+
+extern struct richacl *richacl_from_xattr(struct user_namespace *, const void *, size_t);
+extern size_t richacl_xattr_size(const struct richacl *);
+extern int richacl_to_xattr(struct user_namespace *, const struct richacl *, void *, size_t);
+
+extern void richacl_fix_xattr_from_user(void *, size_t);
+extern void richacl_fix_xattr_to_user(void *, size_t);
+
+#endif /* __RICHACL_XATTR_H */
diff --git a/include/uapi/linux/xattr.h b/include/uapi/linux/xattr.h
index 1590c49..1996903 100644
--- a/include/uapi/linux/xattr.h
+++ b/include/uapi/linux/xattr.h
@@ -73,5 +73,7 @@
 #define XATTR_POSIX_ACL_DEFAULT  "posix_acl_default"
 #define XATTR_NAME_POSIX_ACL_DEFAULT XATTR_SYSTEM_PREFIX XATTR_POSIX_ACL_DEFAULT
 
+#define XATTR_RICHACL "richacl"
+#define XATTR_NAME_RICHACL XATTR_SYSTEM_PREFIX XATTR_RICHACL
 
 #endif /* _UAPI_LINUX_XATTR_H */
-- 
2.4.3

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#1189946 — [PATCH v5 09/39] richacl: Update the file masks in chmod()

From: Andreas Gruenbacher <agruenba@redhat.com>

Doing a chmod() sets the file mode, which includes the file permission
bits.  When a file has a richacl, the permissions that the richacl
grants need to be limited to what the new file permission bits allow.

This is done by setting the file masks in the richacl to what the file
permission bits map to.  The richacl access check algorithm takes the
file masks into account, which ensures that the richacl cannot grant too
many permissions.

It is possible to explicitly add permissions to the file masks which go
beyond what the file permission bits can grant (like the RICHACE_WRITE_ACL
permission).  The POSIX.1 standard calls this an alternate file access
control mechanism.  A subsequent chmod() would ensure that those
permissions are disabled again.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
---
 fs/richacl_base.c       | 40 ++++++++++++++++++++++++++++++++++++++++
 include/linux/richacl.h |  1 +
 2 files changed, 41 insertions(+)

diff --git a/fs/richacl_base.c b/fs/richacl_base.c
index 23e9824..e88cdda 100644
--- a/fs/richacl_base.c
+++ b/fs/richacl_base.c
@@ -334,3 +334,43 @@ restart:
 	acl->a_flags &= ~RICHACL_MASKED;
 }
 EXPORT_SYMBOL_GPL(richacl_compute_max_masks);
+
+/**
+ * richacl_chmod  -  update the file masks to reflect the new mode
+ * @mode:	new file permission bits including the file type
+ *
+ * Return a copy of @acl where the file masks have been replaced by the file
+ * masks corresponding to the file permission bits in @mode, or returns @acl
+ * itself if the file masks are already up to date.  Takes over a reference
+ * to @acl.
+ */
+struct richacl *
+richacl_chmod(struct richacl *acl, mode_t mode)
+{
+	unsigned int x = S_ISDIR(mode) ? 0 : RICHACE_DELETE_CHILD;
+	unsigned int owner_mask, group_mask, other_mask;
+	struct richacl *clone;
+
+	owner_mask = richacl_mode_to_mask(mode >> 6) & ~x;
+	group_mask = richacl_mode_to_mask(mode >> 3) & ~x;
+	other_mask = richacl_mode_to_mask(mode)      & ~x;
+
+	if (acl->a_owner_mask == owner_mask &&
+	    acl->a_group_mask == group_mask &&
+	    acl->a_other_mask == other_mask &&
+	    (acl->a_flags & RICHACL_MASKED))
+		return acl;
+
+	clone = richacl_clone(acl, GFP_KERNEL);
+	richacl_put(acl);
+	if (!clone)
+		return ERR_PTR(-ENOMEM);
+
+	clone->a_flags |= RICHACL_MASKED;
+	clone->a_owner_mask = owner_mask;
+	clone->a_group_mask = group_mask;
+	clone->a_other_mask = other_mask;
+
+	return clone;
+}
+EXPORT_SYMBOL_GPL(richacl_chmod);
diff --git a/include/linux/richacl.h b/include/linux/richacl.h
index 90baca3..e4266dd 100644
--- a/include/linux/richacl.h
+++ b/include/linux/richacl.h
@@ -302,5 +302,6 @@ extern int richacl_masks_to_mode(const struct richacl *);
 extern unsigned int richacl_mode_to_mask(mode_t);
 extern unsigned int richacl_want_to_mask(unsigned int);
 extern void richacl_compute_max_masks(struct richacl *, kuid_t);
+extern struct richacl *richacl_chmod(struct richacl *, mode_t);
 
 #endif /* __RICHACL_H */
-- 
2.4.3

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