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authorAl Viro <viro@zeniv.linux.org.uk>2019-05-09 02:32:28 -0400
committerAl Viro <viro@zeniv.linux.org.uk>2019-05-09 02:32:50 -0400
commit05883eee857eab4693e7d13ebab06716475c5754 (patch)
tree686a142254d360a963f010bb573f4db5fb83e7bc /fs/namespace.c
parent80f232121b69cc69a31ccb2b38c1665d770b0710 (diff)
do_move_mount(): fix an unsafe use of is_anon_ns()
What triggers it is a race between mount --move and umount -l of the source; we should reject it (the source is parentless *and* not the root of anon namespace at that), but the check for namespace being an anon one is broken in that case - is_anon_ns() needs ns to be non-NULL. Better fixed here than in is_anon_ns(), since the rest of the callers is guaranteed to get a non-NULL argument... Reported-by: syzbot+494c7ddf66acac0ad747@syzkaller.appspotmail.com Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/namespace.c')
-rw-r--r--fs/namespace.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/namespace.c b/fs/namespace.c
index 3357c3d65475..ffb13f0562b0 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -2599,7 +2599,7 @@ static int do_move_mount(struct path *old_path, struct path *new_path)
if (attached && !check_mnt(old))
goto out;
- if (!attached && !is_anon_ns(ns))
+ if (!attached && !(ns && is_anon_ns(ns)))
goto out;
if (old->mnt.mnt_flags & MNT_LOCKED)