From 3fa0af4cc8a31d4139ee85a7b0e3d9b4f37b3093 Mon Sep 17 00:00:00 2001 From: Gabriel Totev Date: Wed, 16 Apr 2025 18:42:09 -0400 Subject: [PATCH] apparmor: shift uid when mediating af_unix in userns Avoid unshifted ouids for socket file operations as observed when using AppArmor profiles in unprivileged containers with LXD or Incus. For example, root inside container and uid 1000000 outside, with `owner /root/sock rw,` profile entry for nc: /root$ nc -lkU sock & nc -U sock ==> dmesg apparmor="DENIED" operation="connect" class="file" namespace="root//lxd-podia_" profile="sockit" name="/root/sock" pid=3924 comm="nc" requested_mask="wr" denied_mask="wr" fsuid=1000000 ouid=0 [<== should be 1000000] Fix by performing uid mapping as per common_perm_cond() in lsm.c Signed-off-by: Gabriel Totev Fixes: c05e705812d1 ("apparmor: add fine grained af_unix mediation") Signed-off-by: John Johansen --- security/apparmor/af_unix.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/security/apparmor/af_unix.c b/security/apparmor/af_unix.c index 257648a13bf83..c4e722605fcdc 100644 --- a/security/apparmor/af_unix.c +++ b/security/apparmor/af_unix.c @@ -12,6 +12,7 @@ * License. */ +#include #include #include "include/audit.h" @@ -44,8 +45,11 @@ static int unix_fs_perm(const char *op, u32 mask, const struct cred *subj_cred, */ if (path->dentry) { /* the sunpath may not be valid for this ns so use the path */ - struct path_cond cond = { path->dentry->d_inode->i_uid, - path->dentry->d_inode->i_mode + struct inode *inode = path->dentry->d_inode; + vfsuid_t vfsuid = i_uid_into_vfsuid(mnt_idmap(path->mnt), inode); + struct path_cond cond = { + .uid = vfsuid_into_kuid(vfsuid), + .mode = inode->i_mode, }; return aa_path_perm(op, subj_cred, label, path, -- 2.47.2