6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: John Johansen <john.johansen@xxxxxxxxxxxxx>
[ Upstream commit 8026e40608b4d552216d2a818ca7080a4264bb44 ]
Prevent move_mount from applying the attach_disconnected flag
to move_mount(). This prevents detached mounts from appearing
as / when applying mount mediation, which is not only incorrect
but could result in bad policy being generated.
Basic mount rules like
allow mount,
allow mount options=(move) -> /target/,
will allow detached mounts, allowing older policy to continue
to function. New policy gains the ability to specify `detached` as
a source option
allow mount detached -> /target/,
In addition make sure support of move_mount is advertised as
a feature to userspace so that applications that generate policy
can respond to the addition.
Note: this fixes mediation of move_mount when a detached mount is used,
it does not fix the broader regression of apparmor mediation of
mounts under the new mount api.
Link: https://lore.kernel.org/all/68c166b8-5b4d-4612-8042-1dee3334385b@xxxxxxxxxxxxx/T/#mb35fdde37f999f08f0b02d58dc1bf4e6b65b8da2
Fixes: 157a3537d6bc ("apparmor: Fix regression in mount mediation")
Reviewed-by: Georgia Garcia <georgia.garcia@xxxxxxxxxxxxx>
Signed-off-by: John Johansen <john.johansen@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
security/apparmor/apparmorfs.c | 1 +
security/apparmor/mount.c | 4 ++++
2 files changed, 5 insertions(+)
diff --git a/security/apparmor/apparmorfs.c b/security/apparmor/apparmorfs.c
index 261cef4c622fb..63ddefb6ddd1c 100644
--- a/security/apparmor/apparmorfs.c
+++ b/security/apparmor/apparmorfs.c
@@ -2364,6 +2364,7 @@ static struct aa_sfs_entry aa_sfs_entry_policy[] = {
static struct aa_sfs_entry aa_sfs_entry_mount[] = {
AA_SFS_FILE_STRING("mask", "mount umount pivot_root"),
+ AA_SFS_FILE_STRING("move_mount", "detached"),
{ }
};
diff --git a/security/apparmor/mount.c b/security/apparmor/mount.c
index f2a114e540079..cb0fdbdb82d94 100644
--- a/security/apparmor/mount.c
+++ b/security/apparmor/mount.c
@@ -499,6 +499,10 @@ int aa_move_mount(const struct cred *subj_cred,
error = -ENOMEM;
if (!to_buffer || !from_buffer)
goto out;
+
+ if (!our_mnt(from_path->mnt))
+ /* moving a mount detached from the namespace */
+ from_path = NULL;
error = fn_for_each_confined(label, profile,
match_mnt(subj_cred, profile, to_path, to_buffer,
from_path, from_buffer,
--
2.43.0
