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Groups > linux.kernel > #1254906

[PATCH v12 33/49] richacl: Create richacl from mode values

From Andreas Gruenbacher <agruenba@redhat.com>
Newsgroups linux.kernel
Subject [PATCH v12 33/49] richacl: Create richacl from mode values
Date 2015-10-23 20:50 +0200
Message-ID <qmPzB-1ob-33@gated-at.bofh.it> (permalink)
References <qmPzA-1ob-3@gated-at.bofh.it>
Organization linux.* mail to news gateway

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A file can have "no acl" in the sense that only the file mode permission
bits determine access.  In that case, the getxattr system call fails with
errno == ENODATA (No such attribute).

Over the NFSv4 protocol, a file always has an acl, and we convert the file
mode permission bits into an equivalent acl with richacl_from_mode.  Such
"trivial" acls can be converted back to a file mode with
richacl_equiv_mode.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: J. Bruce Fields <bfields@redhat.com>
---
 fs/richacl_compat.c     | 88 +++++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/richacl.h |  1 +
 2 files changed, 89 insertions(+)

diff --git a/fs/richacl_compat.c b/fs/richacl_compat.c
index ea3effd..3a11773 100644
--- a/fs/richacl_compat.c
+++ b/fs/richacl_compat.c
@@ -827,3 +827,91 @@ richacl_apply_masks(struct richacl **acl, kuid_t owner)
 	return 0;
 }
 EXPORT_SYMBOL_GPL(richacl_apply_masks);
+
+/**
+ * richacl_from_mode  -  create an acl which corresponds to @mode
+ *
+ * The resulting acl doesn't have the RICHACL_MASKED flag set.
+ *
+ * @mode:	file mode including the file type
+ */
+struct richacl *
+richacl_from_mode(umode_t mode)
+{
+	unsigned int owner_mask = richacl_mode_to_mask(mode >> 6);
+	unsigned int group_mask = richacl_mode_to_mask(mode >> 3);
+	unsigned int other_mask = richacl_mode_to_mask(mode);
+	unsigned int denied;
+	unsigned int entries = 0;
+	struct richacl *acl;
+	struct richace *ace;
+
+	/* RICHACE_DELETE_CHILD is meaningless for non-directories. */
+	if (!S_ISDIR(mode)) {
+		owner_mask &= ~RICHACE_DELETE_CHILD;
+		group_mask &= ~RICHACE_DELETE_CHILD;
+		other_mask &= ~RICHACE_DELETE_CHILD;
+	}
+
+	denied = ~owner_mask & (group_mask | other_mask);
+	if (denied)
+		entries++;  /* owner@ deny entry needed */
+	if (owner_mask & ~(group_mask & other_mask))
+		entries++;  /* owner@ allow entry needed */
+	denied = ~group_mask & other_mask;
+	if (denied)
+		entries++;  /* group@ deny entry needed */
+	if (group_mask & ~other_mask)
+		entries++;  /* group@ allow entry needed */
+	if (other_mask)
+		entries++;  /* everyone@ allow entry needed */
+
+	acl = richacl_alloc(entries, GFP_KERNEL);
+	if (!acl)
+		return NULL;
+	acl->a_owner_mask = owner_mask;
+	acl->a_group_mask = group_mask;
+	acl->a_other_mask = other_mask;
+	ace = acl->a_entries;
+
+	denied = ~owner_mask & (group_mask | other_mask);
+	if (denied) {
+		ace->e_type = RICHACE_ACCESS_DENIED_ACE_TYPE;
+		ace->e_flags = RICHACE_SPECIAL_WHO;
+		ace->e_mask = denied;
+		ace->e_id.special = RICHACE_OWNER_SPECIAL_ID;
+		ace++;
+	}
+	if (owner_mask & ~(group_mask & other_mask)) {
+		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;
+		ace++;
+	}
+	denied = ~group_mask & other_mask;
+	if (denied) {
+		ace->e_type = RICHACE_ACCESS_DENIED_ACE_TYPE;
+		ace->e_flags = RICHACE_SPECIAL_WHO;
+		ace->e_mask = denied;
+		ace->e_id.special = RICHACE_GROUP_SPECIAL_ID;
+		ace++;
+	}
+	if (group_mask & ~other_mask) {
+		ace->e_type = RICHACE_ACCESS_ALLOWED_ACE_TYPE;
+		ace->e_flags = RICHACE_SPECIAL_WHO;
+		ace->e_mask = group_mask;
+		ace->e_id.special = RICHACE_GROUP_SPECIAL_ID;
+		ace++;
+	}
+	if (other_mask) {
+		ace->e_type = RICHACE_ACCESS_ALLOWED_ACE_TYPE;
+		ace->e_flags = RICHACE_SPECIAL_WHO;
+		ace->e_mask = other_mask;
+		ace->e_id.special = RICHACE_EVERYONE_SPECIAL_ID;
+		ace++;
+	}
+
+	return acl;
+}
+EXPORT_SYMBOL_GPL(richacl_from_mode);
diff --git a/include/linux/richacl.h b/include/linux/richacl.h
index 3fdfc57..10bfd0f 100644
--- a/include/linux/richacl.h
+++ b/include/linux/richacl.h
@@ -207,5 +207,6 @@ extern struct richacl *richacl_create(umode_t *, struct inode *);
 
 /* richacl_compat.c */
 extern int richacl_apply_masks(struct richacl **, kuid_t);
+extern struct richacl *richacl_from_mode(umode_t);
 
 #endif /* __RICHACL_H */
-- 
2.5.0

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Thread

[PATCH v12 00/49] Richacls Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 04/49] vfs: Make the inode passed to inode_change_ok non-const Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 01/49] vfs: Add IS_ACL() and IS_RICHACL() tests Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 08/49] richacl: Compute maximum file masks from an acl Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 38/49] nfsd: Add support for the MAY_CREATE_{FILE,DIR} permissions Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 25/49] xfs: Add richacl support Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 09/49] richacl: Permission check algorithm Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 34/49] nfsd: Keep list of acls to dispose of in compoundargs Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 42/49] xfs: Don't allow unmapped identifiers in richacls Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 13/49] richacl: Update the file masks in chmod() Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 32/49] richacl: Apply the file masks to a richacl Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 28/49] richacl: Propagate everyone@ permissions to other aces Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 49/49] nfs: Add support for the v4.1 dacl attribute Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 41/49] ext4: Don't allow unmapped identifiers in richacls Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 33/49] richacl: Create richacl from mode values Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 03/49] vfs: Add MAY_DELETE_SELF and MAY_DELETE_CHILD permission flags Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 12/49] vfs: Cache richacl in struct inode Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 44/49] sunrpc: Add xdr_init_encode_pages Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 16/49] richacl: Automatic Inheritance Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 29/49] richacl: Set the owner permissions to the owner mask Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 17/49] richacl: xattr mapping functions Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 20/49] ext4: Add richacl support Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 06/49] richacl: In-memory representation and helper functions Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 45/49] nfs: Fix GETATTR bitmap verification Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 15/49] richacl: Create-time inheritance Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 48/49] nfs: Add richacl support Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 35/49] nfsd: Use richacls as internal acl representation Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 21/49] ext4: Add richacl feature flag Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
    Re: [PATCH v12 21/49] ext4: Add richacl feature flag Austin S Hemmelgarn <ahferroin7@gmail.com> - 2015-10-23 21:40 +0200
  [PATCH v12 47/49] nfs: Distinguish missing users and groups from nobody Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 24/49] xfs: Change how listxattr generates synthetic attributes Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 31/49] richacl: Isolate the owner and group classes Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 26/49] richacl: acl editing helper functions Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 02/49] vfs: Add MAY_CREATE_FILE and MAY_CREATE_DIR permission flags Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 05/49] vfs: Add permission flags for setting file attributes Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 19/49] vfs: Add richacl permission checking Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 14/49] richacl: Check if an acl is equivalent to a file mode Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 07/49] richacl: Permission mapping functions Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 40/49] nfsd: Add support for unmapped richace identifiers Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 11/49] vfs: Add get_richacl and set_richacl inode operations Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 39/49] richacl: Add support for unmapped identifiers Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 43/49] sunrpc: Allow to demand-allocate pages to encode into Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 37/49] nfsd: Add support for the v4.1 dacl attribute Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 20:50 +0200
  [PATCH v12 36/49] nfsd: Add richacl support Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 21:00 +0200
  [PATCH v12 27/49] richacl: Move everyone@ aces down the acl Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 21:10 +0200
  [PATCH v12 30/49] richacl: Set the other permissions to the other mask Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 21:10 +0200
  [PATCH v12 23/49] xfs: Make xfs_set_mode non-static Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 21:20 +0200
  [PATCH v12 18/49] richacl: Add richacl xattr handler Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 21:20 +0200
  [PATCH v12 22/49] xfs: Fix error path in xfs_get_acl Andreas Gruenbacher <agruenba@redhat.com> - 2015-10-23 21:20 +0200
  RE: [PATCH v12 00/49] Richacls "Frank Filz" <ffilzlnx@mindspring.com> - 2015-10-23 22:20 +0200

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