diff options
| author | Thomas Gleixner <tglx@linutronix.de> | 2021-07-06 16:36:54 +0200 |
|---|---|---|
| committer | Sebastian Andrzej Siewior <bigeasy@linutronix.de> | 2021-08-16 10:41:48 +0200 |
| commit | 7384201f9701c226cb1dd04cf76c12c33762bb30 (patch) | |
| tree | cc37f8001a2e71cfb5a76ed39239f917daefff2d | |
| parent | 5fc824e6e0d0596a5db2fa778857a0f7293ed27d (diff) | |
| download | linux-rt-devel-7384201f9701c226cb1dd04cf76c12c33762bb30.tar.gz | |
futex: Validate waiter correctly in futex_proxy_trylock_atomic()
Notice: this object is not reachable from any branch.
The loop in futex_requeue() has a sanity check for the waiter which is
missing in futex_proxy_trylock_atomic(). In theory the key2 check is
sufficient, but futexes are cursed so add it for completeness and paranoia
sake.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Notice: this object is not reachable from any branch.
| -rw-r--r-- | kernel/futex.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/kernel/futex.c b/kernel/futex.c index 21625cb3e865c..a1f27fd55a232 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -1879,6 +1879,13 @@ futex_proxy_trylock_atomic(u32 __user *pifutex, struct futex_hash_bucket *hb1, if (!top_waiter) return 0; + /* + * Ensure that this is a waiter sitting in futex_wait_requeue_pi() + * and waiting on the 'waitqueue' futex which is always !PI. + */ + if (!top_waiter->rt_waiter || top_waiter->pi_state) + ret = -EINVAL; + /* Ensure we requeue to the expected futex. */ if (!match_futex(top_waiter->requeue_pi_key, key2)) return -EINVAL; |