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authorAndreas Gruenbacher <agruen@suse.de>2006-11-02 22:07:29 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2006-11-03 12:27:59 -0800
commitf1f2d8713d16a1e198880bbc716eb24fae09c858 (patch)
tree1782ba01540c329481d995e87b80d45047ea4a9c
parent8ce08464d2c749610a52c4d6c7c11080a7eaaef1 (diff)
[PATCH] Fix user.* xattr permission check for sticky dirs
The user.* extended attributes are only allowed on regular files and directories. Sticky directories further restrict write access to the owner and privileged users. (See the attr(5) man page for an explanation.) The original check in ext2/ext3 when user.* xattrs were merged was more restrictive than intended, and when the xattr permission checks were moved into the VFS, read access to user.* attributes on sticky directores ended up being denied in addition. Originally-from: Gerard Neil <xyzzy@devferret.org> Signed-off-by: Andreas Gruenbacher <agruen@suse.de> Cc: Dave Kleikamp <shaggy@austin.ibm.com> Cc: Jan Engelhardt <jengelh@linux01.gwdg.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r--fs/xattr.c13
1 files changed, 10 insertions, 3 deletions
diff --git a/fs/xattr.c b/fs/xattr.c
index 395635100f7..0901bdc2ce2 100644
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -48,14 +48,21 @@ xattr_permission(struct inode *inode, const char *name, int mask)
return 0;
/*
- * The trusted.* namespace can only accessed by a privilegued user.
+ * The trusted.* namespace can only be accessed by a privileged user.
*/
if (!strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN))
return (capable(CAP_SYS_ADMIN) ? 0 : -EPERM);
+ /* In user.* namespace, only regular files and directories can have
+ * extended attributes. For sticky directories, only the owner and
+ * privileged user can write attributes.
+ */
if (!strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN)) {
- if (!S_ISREG(inode->i_mode) &&
- (!S_ISDIR(inode->i_mode) || inode->i_mode & S_ISVTX))
+ if (!S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode))
+ return -EPERM;
+ if (S_ISDIR(inode->i_mode) && (inode->i_mode & S_ISVTX) &&
+ (mask & MAY_WRITE) && (current->fsuid != inode->i_uid) &&
+ !capable(CAP_FOWNER))
return -EPERM;
}