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| author | David Howells <dhowells@redhat.com> | 2025-03-19 18:57:46 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-03-29 00:03:30 +0300 |
| commit | 6afe2ea2daec156bd94ad2c5a6f4f4c48240dcd3 (patch) | |
| tree | 47969bdfb5514e32186039a0080c45b9eb7be51a /include | |
| parent | 8332847875f75f91e8de1e518fb63441a1dc782d (diff) | |
| download | linux-6afe2ea2daec156bd94ad2c5a6f4f4c48240dcd3.tar.xz | |
keys: Fix UAF in key_put()
commit 75845c6c1a64483e9985302793dbf0dfa5f71e32 upstream.
Once a key's reference count has been reduced to 0, the garbage collector
thread may destroy it at any time and so key_put() is not allowed to touch
the key after that point. The most key_put() is normally allowed to do is
to touch key_gc_work as that's a static global variable.
However, in an effort to speed up the reclamation of quota, this is now
done in key_put() once the key's usage is reduced to 0 - but now the code
is looking at the key after the deadline, which is forbidden.
Fix this by using a flag to indicate that a key can be gc'd now rather than
looking at the key's refcount in the garbage collector.
Fixes: 9578e327b2b4 ("keys: update key quotas in key_put()")
Reported-by: syzbot+6105ffc1ded71d194d6d@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/673b6aec.050a0220.87769.004a.GAE@google.com/
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: syzbot+6105ffc1ded71d194d6d@syzkaller.appspotmail.com
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/key.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/key.h b/include/linux/key.h index 074dca3222b9..ba05de8579ec 100644 --- a/include/linux/key.h +++ b/include/linux/key.h @@ -236,6 +236,7 @@ struct key { #define KEY_FLAG_ROOT_CAN_INVAL 7 /* set if key can be invalidated by root without permission */ #define KEY_FLAG_KEEP 8 /* set if key should not be removed */ #define KEY_FLAG_UID_KEYRING 9 /* set if key is a user or user session keyring */ +#define KEY_FLAG_FINAL_PUT 10 /* set if final put has happened on key */ /* the key type and key description string * - the desc is used to match a key against search criteria |