diff options
| author | Gabriel Totev <gabriel.totev@zetier.com> | 2025-04-16 18:42:08 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-08-20 18:41:28 +0200 |
| commit | b6fba5d79289c94716774ae4ef8c41cd701988ae (patch) | |
| tree | c0496b28165ee591715dea13d222e306f13962ed | |
| parent | 06433d70bde12afccebac816e4da2f3ffe241326 (diff) | |
apparmor: shift ouid when mediating hard links in userns
[ Upstream commit c5bf96d20fd787e4909b755de4705d52f3458836 ]
When using AppArmor profiles inside an unprivileged container,
the link operation observes an unshifted ouid.
(tested with LXD and Incus)
For example, root inside container and uid 1000000 outside, with
`owner /root/link l,` profile entry for ln:
/root$ touch chain && ln chain link
==> dmesg
apparmor="DENIED" operation="link" class="file"
namespace="root//lxd-feet_<var-snap-lxd-common-lxd>" profile="linkit"
name="/root/link" pid=1655 comm="ln" requested_mask="l" denied_mask="l"
fsuid=1000000 ouid=0 [<== should be 1000000] target="/root/chain"
Fix by mapping inode uid of old_dentry in aa_path_link() rather than
using it directly, similarly to how it's mapped in __file_path_perm()
later in the file.
Signed-off-by: Gabriel Totev <gabriel.totev@zetier.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | security/apparmor/file.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/security/apparmor/file.c b/security/apparmor/file.c index d52a5b14dad4..62bc46e03758 100644 --- a/security/apparmor/file.c +++ b/security/apparmor/file.c @@ -423,9 +423,11 @@ int aa_path_link(const struct cred *subj_cred, { struct path link = { .mnt = new_dir->mnt, .dentry = new_dentry }; struct path target = { .mnt = new_dir->mnt, .dentry = old_dentry }; + struct inode *inode = d_backing_inode(old_dentry); + vfsuid_t vfsuid = i_uid_into_vfsuid(mnt_idmap(target.mnt), inode); struct path_cond cond = { - d_backing_inode(old_dentry)->i_uid, - d_backing_inode(old_dentry)->i_mode + .uid = vfsuid_into_kuid(vfsuid), + .mode = inode->i_mode, }; char *buffer = NULL, *buffer2 = NULL; struct aa_profile *profile; |