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author | Sebastian Andrzej Siewior <bigeasy@linutronix.de> | 2022-05-04 17:07:36 +0200 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-06-14 18:11:41 +0200 |
commit | dd8c886953dba44b747c28feb2396ad2f5f8a0bf (patch) | |
tree | 4ff940e23b1a3a103f5a2068b454228efaea6379 | |
parent | 4fab6773c7bc4a6f51e81cfb590ae77513fcbb79 (diff) | |
download | linux-crypto-dd8c886953dba44b747c28feb2396ad2f5f8a0bf.tar.gz linux-crypto-dd8c886953dba44b747c28feb2396ad2f5f8a0bf.zip |
crypto: cryptd - Protect per-CPU resource by disabling BH.
[ Upstream commit 91e8bcd7b4da182e09ea19a2c73167345fe14c98 ]
The access to cryptd_queue::cpu_queue is synchronized by disabling
preemption in cryptd_enqueue_request() and disabling BH in
cryptd_queue_worker(). This implies that access is allowed from BH.
If cryptd_enqueue_request() is invoked from preemptible context _and_
soft interrupt then this can lead to list corruption since
cryptd_enqueue_request() is not protected against access from
soft interrupt.
Replace get_cpu() in cryptd_enqueue_request() with local_bh_disable()
to ensure BH is always disabled.
Remove preempt_disable() from cryptd_queue_worker() since it is not
needed because local_bh_disable() ensures synchronisation.
Fixes: a045a18f0207 ("crypto: cryptd - Per-CPU thread implementation...")
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
-rw-r--r-- | crypto/cryptd.c | 23 |
1 files changed, 11 insertions, 12 deletions
diff --git a/crypto/cryptd.c b/crypto/cryptd.c index 927760b3..43a1a855 100644 --- a/crypto/cryptd.c +++ b/crypto/cryptd.c @@ -39,6 +39,10 @@ struct cryptd_cpu_queue { }; struct cryptd_queue { + /* + * Protected by disabling BH to allow enqueueing from softinterrupt and + * dequeuing from kworker (cryptd_queue_worker()). + */ struct cryptd_cpu_queue __percpu *cpu_queue; }; @@ -125,28 +129,28 @@ static void cryptd_fini_queue(struct cryptd_queue *queue) static int cryptd_enqueue_request(struct cryptd_queue *queue, struct crypto_async_request *request) { - int cpu, err; + int err; struct cryptd_cpu_queue *cpu_queue; refcount_t *refcnt; - cpu = get_cpu(); + local_bh_disable(); cpu_queue = this_cpu_ptr(queue->cpu_queue); err = crypto_enqueue_request(&cpu_queue->queue, request); refcnt = crypto_tfm_ctx(request->tfm); if (err == -ENOSPC) - goto out_put_cpu; + goto out; - queue_work_on(cpu, cryptd_wq, &cpu_queue->work); + queue_work_on(smp_processor_id(), cryptd_wq, &cpu_queue->work); if (!refcount_read(refcnt)) - goto out_put_cpu; + goto out; refcount_inc(refcnt); -out_put_cpu: - put_cpu(); +out: + local_bh_enable(); return err; } @@ -162,15 +166,10 @@ static void cryptd_queue_worker(struct work_struct *work) cpu_queue = container_of(work, struct cryptd_cpu_queue, work); /* * Only handle one request at a time to avoid hogging crypto workqueue. - * preempt_disable/enable is used to prevent being preempted by - * cryptd_enqueue_request(). local_bh_disable/enable is used to prevent - * cryptd_enqueue_request() being accessed from software interrupts. */ local_bh_disable(); - preempt_disable(); backlog = crypto_get_backlog(&cpu_queue->queue); req = crypto_dequeue_request(&cpu_queue->queue); - preempt_enable(); local_bh_enable(); if (!req) |