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Groups > linux.kernel > #1265588
| From | Andreas Gruenbacher <agruenba@redhat.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [PATCH v15 16/22] richacl: Create-time inheritance |
| Date | 2015-11-09 12:20 +0100 |
| Message-ID | <qsSEr-5Hy-45@gated-at.bofh.it> (permalink) |
| References | <qsSuJ-5Ec-7@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
When a new file is created, it can inherit an acl from its parent
directory; this is similar to how default acls work in POSIX (draft)
ACLs.
As with POSIX ACLs, if a file inherits an acl from its parent directory,
the intersection between the create mode and the permissions granted by
the inherited acl determines the file masks and file permission bits,
and the umask is ignored.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: J. Bruce Fields <bfields@redhat.com>
---
fs/richacl_base.c | 68 +++++++++++++++++++++++++++++++++++++++++++++++
fs/richacl_inode.c | 70 +++++++++++++++++++++++++++++++++++++++++++++++++
include/linux/richacl.h | 2 ++
3 files changed, 140 insertions(+)
diff --git a/fs/richacl_base.c b/fs/richacl_base.c
index 74e5cb5..3753216 100644
--- a/fs/richacl_base.c
+++ b/fs/richacl_base.c
@@ -486,3 +486,71 @@ richacl_equiv_mode(const struct richacl *acl, umode_t *mode_p)
return 0;
}
EXPORT_SYMBOL_GPL(richacl_equiv_mode);
+
+/**
+ * richacl_inherit - compute the inherited acl of a new file
+ * @dir_acl: acl of the containing directory
+ * @isdir: inherit by a directory or non-directory?
+ *
+ * A directory can have acl entries which files and/or directories created
+ * inside the directory will inherit. This function computes the acl for such
+ * a new file. If there is no inheritable acl, it will return %NULL.
+ */
+struct richacl *
+richacl_inherit(const struct richacl *dir_acl, int isdir)
+{
+ const struct richace *dir_ace;
+ struct richacl *acl = NULL;
+ struct richace *ace;
+ int count = 0;
+
+ if (isdir) {
+ richacl_for_each_entry(dir_ace, dir_acl) {
+ if (!richace_is_inheritable(dir_ace))
+ continue;
+ count++;
+ }
+ if (!count)
+ return NULL;
+ acl = richacl_alloc(count, GFP_KERNEL);
+ if (!acl)
+ return ERR_PTR(-ENOMEM);
+ ace = acl->a_entries;
+ 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)
+ ace->e_flags &= ~RICHACE_INHERITANCE_FLAGS;
+ else if (!(dir_ace->e_flags & RICHACE_DIRECTORY_INHERIT_ACE))
+ ace->e_flags |= RICHACE_INHERIT_ONLY_ACE;
+ ace++;
+ }
+ } else {
+ richacl_for_each_entry(dir_ace, dir_acl) {
+ if (!(dir_ace->e_flags & RICHACE_FILE_INHERIT_ACE))
+ continue;
+ count++;
+ }
+ if (!count)
+ return NULL;
+ acl = richacl_alloc(count, GFP_KERNEL);
+ if (!acl)
+ return ERR_PTR(-ENOMEM);
+ ace = acl->a_entries;
+ richacl_for_each_entry(dir_ace, dir_acl) {
+ if (!(dir_ace->e_flags & RICHACE_FILE_INHERIT_ACE))
+ continue;
+ richace_copy(ace, dir_ace);
+ ace->e_flags &= ~RICHACE_INHERITANCE_FLAGS;
+ /*
+ * RICHACE_DELETE_CHILD is meaningless for
+ * non-directories, so clear it.
+ */
+ ace->e_mask &= ~RICHACE_DELETE_CHILD;
+ ace++;
+ }
+ }
+
+ return acl;
+}
diff --git a/fs/richacl_inode.c b/fs/richacl_inode.c
index e329826..ec3d2c8 100644
--- a/fs/richacl_inode.c
+++ b/fs/richacl_inode.c
@@ -254,3 +254,73 @@ richacl_chmod(struct inode *inode, umode_t mode)
return retval;
}
EXPORT_SYMBOL(richacl_chmod);
+
+/*
+ * richacl_inherit_inode - compute inherited acl and file mode
+ * @dir_acl: acl of the containing directory
+ * @mode_p: mode of the new inode
+ *
+ * The file permission bits in @mode_p must be set to the create mode by the
+ * caller.
+ *
+ * If there is an inheritable acl, the maximum permissions that the acl grants
+ * are computed and the file masks of the new acl are set accordingly.
+ */
+static struct richacl *
+richacl_inherit_inode(const struct richacl *dir_acl, umode_t *mode_p)
+{
+ struct richacl *acl;
+ umode_t mode = *mode_p;
+
+ acl = richacl_inherit(dir_acl, S_ISDIR(mode));
+ if (acl) {
+ if (richacl_equiv_mode(acl, &mode) == 0) {
+ *mode_p &= mode;
+ richacl_put(acl);
+ acl = NULL;
+ } else {
+ richacl_compute_max_masks(acl);
+ /*
+ * Ensure that the acl will not grant any permissions
+ * beyond the create mode.
+ */
+ acl->a_flags |= RICHACL_MASKED;
+ acl->a_owner_mask &=
+ richacl_mode_to_mask(mode >> 6);
+ acl->a_group_mask &=
+ richacl_mode_to_mask(mode >> 3);
+ acl->a_other_mask &=
+ richacl_mode_to_mask(mode);
+ }
+ } else
+ *mode_p &= ~current_umask();
+
+ return acl;
+}
+
+/**
+ * richacl_create - filesystem create helper
+ * @mode_p: mode of the new inode
+ * @dir: containing directory
+ *
+ * Compute the inherited acl for a new inode. If there is no acl to inherit,
+ * apply the umask. Use when creating a new inode on a richacl enabled file
+ * system.
+ */
+struct richacl *richacl_create(umode_t *mode_p, struct inode *dir)
+{
+ struct richacl *dir_acl, *acl = NULL;
+
+ if (S_ISLNK(*mode_p))
+ return NULL;
+ dir_acl = get_richacl(dir);
+ if (dir_acl) {
+ if (IS_ERR(dir_acl))
+ return dir_acl;
+ acl = richacl_inherit_inode(dir_acl, mode_p);
+ richacl_put(dir_acl);
+ } else
+ *mode_p &= ~current_umask();
+ return acl;
+}
+EXPORT_SYMBOL_GPL(richacl_create);
diff --git a/include/linux/richacl.h b/include/linux/richacl.h
index b7128bf..c8fae91a 100644
--- a/include/linux/richacl.h
+++ b/include/linux/richacl.h
@@ -186,9 +186,11 @@ extern unsigned int richacl_want_to_mask(unsigned int);
extern void richacl_compute_max_masks(struct richacl *);
extern struct richacl *__richacl_chmod(struct richacl *, umode_t);
extern int richacl_equiv_mode(const struct richacl *, umode_t *);
+extern struct richacl *richacl_inherit(const struct richacl *, int);
/* richacl_inode.c */
extern int richacl_permission(struct inode *, const struct richacl *, int);
extern int richacl_chmod(struct inode *, umode_t);
+extern struct richacl *richacl_create(umode_t *, struct inode *);
#endif /* __RICHACL_H */
--
2.5.0
--
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[PATCH v15 00/22] Richacls (Core and Ext4) Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-09 12:10 +0100
[PATCH v15 02/22] vfs: Add MAY_CREATE_FILE and MAY_CREATE_DIR permission flags Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-09 12:10 +0100
[PATCH v15 21/22] ext4: Add richacl support Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-09 12:20 +0100
[PATCH v15 06/22] richacl: In-memory representation and helper functions Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-09 12:20 +0100
[PATCH v15 20/22] vfs: Add richacl permission checking Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-09 12:20 +0100
[PATCH v15 09/22] richacl: Permission check algorithm Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-09 12:20 +0100
[PATCH v15 14/22] richacl: Update the file masks in chmod() Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-09 12:20 +0100
[PATCH v15 19/22] richacl: Add richacl xattr handler Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-09 12:20 +0100
Re: [PATCH v15 19/22] richacl: Add richacl xattr handler Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-11 02:20 +0100
[PATCH v15 18/22] richacl: xattr mapping functions Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-09 12:20 +0100
[PATCH v15 22/22] ext4: Add richacl feature flag Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-09 12:20 +0100
[PATCH v15 08/22] richacl: Compute maximum file masks from an acl Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-09 12:20 +0100
[PATCH v15 13/22] vfs: Cache richacl in struct inode Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-09 12:20 +0100
[PATCH v15 17/22] richacl: Automatic Inheritance Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-09 12:20 +0100
[PATCH v15 12/22] vfs: Add get_richacl and set_richacl inode operations Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-09 12:20 +0100
[PATCH v15 15/22] richacl: Check if an acl is equivalent to a file mode Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-09 12:20 +0100
[PATCH v15 16/22] richacl: Create-time inheritance Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-09 12:20 +0100
[PATCH v15 10/22] posix_acl: Unexport acl_by_type and make it static Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-09 12:20 +0100
[PATCH v15 11/22] vfs: Cache base_acl objects in inodes Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-09 12:30 +0100
[PATCH v15 07/22] richacl: Permission mapping functions Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-09 12:30 +0100
[PATCH v15 01/22] vfs: Add IS_ACL() and IS_RICHACL() tests Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-09 12:30 +0100
Re: [PATCH v15 00/22] Richacls (Core and Ext4) Christoph Hellwig <hch@infradead.org> - 2015-11-10 12:30 +0100
Re: [PATCH v15 00/22] Richacls (Core and Ext4) Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-10 13:50 +0100
Re: [PATCH v15 00/22] Richacls (Core and Ext4) Steve French <smfrench@gmail.com> - 2015-11-10 17:50 +0100
Re: [PATCH v15 00/22] Richacls (Core and Ext4) "J. Bruce Fields" <bfields@fieldses.org> - 2015-11-10 18:10 +0100
Re: [PATCH v15 00/22] Richacls (Core and Ext4) Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-10 19:10 +0100
Re: [PATCH v15 00/22] Richacls (Core and Ext4) "J. Bruce Fields" <bfields@fieldses.org> - 2015-11-10 20:20 +0100
Re: [PATCH v15 00/22] Richacls (Core and Ext4) Christoph Hellwig <hch@infradead.org> - 2015-11-11 09:00 +0100
Re: [PATCH v15 00/22] Richacls (Core and Ext4) Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-11 15:00 +0100
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