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authorAndreas Gruenbacher <agruen@kernel.org>2011-05-27 14:50:36 +0200
committerAl Viro <viro@zeniv.linux.org.uk>2011-05-27 09:43:00 -0400
commit55b23bde19c08f14127a27d461a4e079942c7258 (patch)
tree074f23a530c5bbaccce7068bf2947bf39b60ab16 /fs/xattr.c
parentaa38572954ade525817fe88c54faebf85e5a61c0 (diff)
downloadvexpress-lsk-55b23bde19c08f14127a27d461a4e079942c7258.tar.gz
xattr: Fix error results for non-existent / invisible attributes
Return -ENODATA when trying to read a user.* attribute which cannot exist: user space otherwise does not have a reasonable way to distinguish between non-existent and inaccessible attributes. Likewise, return -ENODATA when an unprivileged process tries to read a trusted.* attribute: to unprivileged processes, those attributes are invisible (listxattr() won't include them). Related to this bug report: https://bugzilla.redhat.com/660613 Signed-off-by: Andreas Gruenbacher <agruen@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/xattr.c')
-rw-r--r--fs/xattr.c16
1 files changed, 10 insertions, 6 deletions
diff --git a/fs/xattr.c b/fs/xattr.c
index f1ef94974de..4be2e7666d0 100644
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -46,18 +46,22 @@ xattr_permission(struct inode *inode, const char *name, int mask)
return 0;
/*
- * The trusted.* namespace can only be accessed by a privileged user.
+ * The trusted.* namespace can only be accessed by privileged users.
*/
- if (!strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN))
- return (capable(CAP_SYS_ADMIN) ? 0 : -EPERM);
+ if (!strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN)) {
+ if (!capable(CAP_SYS_ADMIN))
+ return (mask & MAY_WRITE) ? -EPERM : -ENODATA;
+ return 0;
+ }
- /* In user.* namespace, only regular files and directories can have
+ /*
+ * In the user.* namespace, only regular files and directories can have
* extended attributes. For sticky directories, only the owner and
- * privileged user can write attributes.
+ * privileged users can write attributes.
*/
if (!strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN)) {
if (!S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode))
- return -EPERM;
+ return (mask & MAY_WRITE) ? -EPERM : -ENODATA;
if (S_ISDIR(inode->i_mode) && (inode->i_mode & S_ISVTX) &&
(mask & MAY_WRITE) && !inode_owner_or_capable(inode))
return -EPERM;