diff options
| author | Andy Lutomirski <luto@amacapital.net> | 2014-06-10 12:45:42 -0700 |
|---|---|---|
| committer | Jiri Slaby <jslaby@suse.cz> | 2014-06-20 17:34:15 +0200 |
| commit | 2246a472bce19c0d373fb5488a0e612e3328ce0a (patch) | |
| tree | e32ba1986319c382ab288f41ecf7eb242b5899f5 /fs/inode.c | |
| parent | 21af26cb47416f782c39b4055eb7de21476838a5 (diff) | |
| download | lwn-2246a472bce19c0d373fb5488a0e612e3328ce0a.tar.gz lwn-2246a472bce19c0d373fb5488a0e612e3328ce0a.zip | |
fs,userns: Change inode_capable to capable_wrt_inode_uidgid
commit 23adbe12ef7d3d4195e80800ab36b37bee28cd03 upstream.
The kernel has no concept of capabilities with respect to inodes; inodes
exist independently of namespaces. For example, inode_capable(inode,
CAP_LINUX_IMMUTABLE) would be nonsense.
This patch changes inode_capable to check for uid and gid mappings and
renames it to capable_wrt_inode_uidgid, which should make it more
obvious what it does.
Fixes CVE-2014-4014.
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Serge Hallyn <serge.hallyn@ubuntu.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Dave Chinner <david@fromorbit.com>
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Diffstat (limited to 'fs/inode.c')
| -rw-r--r-- | fs/inode.c | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/fs/inode.c b/fs/inode.c index b33ba8e021cc..1e6e8468f2d8 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -1808,14 +1808,18 @@ EXPORT_SYMBOL(inode_init_owner); * inode_owner_or_capable - check current task permissions to inode * @inode: inode being checked * - * Return true if current either has CAP_FOWNER to the inode, or - * owns the file. + * Return true if current either has CAP_FOWNER in a namespace with the + * inode owner uid mapped, or owns the file. */ bool inode_owner_or_capable(const struct inode *inode) { + struct user_namespace *ns; + if (uid_eq(current_fsuid(), inode->i_uid)) return true; - if (inode_capable(inode, CAP_FOWNER)) + + ns = current_user_ns(); + if (ns_capable(ns, CAP_FOWNER) && kuid_has_mapping(ns, inode->i_uid)) return true; return false; } |