Messages in this thread Patch in this message | ![/](/images/icornerl.gif) | | From | Eric Dumazet <> | Date | Thu, 11 Jan 2024 17:26:17 +0100 | Subject | Re: [PATCH net] wireguard: receive: annotate data-race around receiving_counter.counter |
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On Thu, Jan 11, 2024 at 4:41 PM Nikita Zhandarovich <n.zhandarovich@fintech.ru> wrote: > > Syzkaller with KCSAN identified a data-race issue [1] when accessing > keypair->receiving_counter.counter. > > This patch uses READ_ONCE() and WRITE_ONCE() annotations to fix the > problem. > > [1] > BUG: KCSAN: data-race in wg_packet_decrypt_worker / wg_packet_rx_poll > > write to 0xffff888107765888 of 8 bytes by interrupt on cpu 0: > counter_validate drivers/net/wireguard/receive.c:321 [inline] > wg_packet_rx_poll+0x3ac/0xf00 drivers/net/wireguard/receive.c:461 > __napi_poll+0x60/0x3b0 net/core/dev.c:6536 > napi_poll net/core/dev.c:6605 [inline] > net_rx_action+0x32b/0x750 net/core/dev.c:6738 > __do_softirq+0xc4/0x279 kernel/softirq.c:553 > do_softirq+0x5e/0x90 kernel/softirq.c:454 > __local_bh_enable_ip+0x64/0x70 kernel/softirq.c:381 > __raw_spin_unlock_bh include/linux/spinlock_api_smp.h:167 [inline] > _raw_spin_unlock_bh+0x36/0x40 kernel/locking/spinlock.c:210 > spin_unlock_bh include/linux/spinlock.h:396 [inline] > ptr_ring_consume_bh include/linux/ptr_ring.h:367 [inline] > wg_packet_decrypt_worker+0x6c5/0x700 drivers/net/wireguard/receive.c:499 > process_one_work kernel/workqueue.c:2633 [inline] > ... > > read to 0xffff888107765888 of 8 bytes by task 3196 on cpu 1: > decrypt_packet drivers/net/wireguard/receive.c:252 [inline] > wg_packet_decrypt_worker+0x220/0x700 drivers/net/wireguard/receive.c:501 > process_one_work kernel/workqueue.c:2633 [inline] > process_scheduled_works+0x5b8/0xa30 kernel/workqueue.c:2706 > worker_thread+0x525/0x730 kernel/workqueue.c:2787 > ... > > Fixes: a9e90d9931f3 ("wireguard: noise: separate receive counter from send counter") > Reported-by: syzbot+d1de830e4ecdaac83d89@syzkaller.appspotmail.com > Signed-off-by: Nikita Zhandarovich <n.zhandarovich@fintech.ru> > --- > drivers/net/wireguard/receive.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/net/wireguard/receive.c b/drivers/net/wireguard/receive.c > index a176653c8861..d91383afb6e2 100644 > --- a/drivers/net/wireguard/receive.c > +++ b/drivers/net/wireguard/receive.c > @@ -251,7 +251,7 @@ static bool decrypt_packet(struct sk_buff *skb, struct noise_keypair *keypair) > > if (unlikely(!READ_ONCE(keypair->receiving.is_valid) || > wg_birthdate_has_expired(keypair->receiving.birthdate, REJECT_AFTER_TIME) || > - keypair->receiving_counter.counter >= REJECT_AFTER_MESSAGES)) { > + READ_ONCE(keypair->receiving_counter.counter) >= REJECT_AFTER_MESSAGES)) { > WRITE_ONCE(keypair->receiving.is_valid, false); > return false; > } > @@ -318,7 +318,7 @@ static bool counter_validate(struct noise_replay_counter *counter, u64 their_cou > for (i = 1; i <= top; ++i) > counter->backtrack[(i + index_current) & > ((COUNTER_BITS_TOTAL / BITS_PER_LONG) - 1)] = 0; > - counter->counter = their_counter; > + WRITE_ONCE(counter->counter, their_counter); > } > > index &= (COUNTER_BITS_TOTAL / BITS_PER_LONG) - 1;
It seems you forgot to add this as well ?
diff --git a/drivers/net/wireguard/receive.c b/drivers/net/wireguard/receive.c index a176653c88616b1bc871fe52fcea778b5e189f69..a1493c94cea042165f8523a4dac573800a6d03c4 100644 --- a/drivers/net/wireguard/receive.c +++ b/drivers/net/wireguard/receive.c @@ -463,7 +463,7 @@ int wg_packet_rx_poll(struct napi_struct *napi, int budget) net_dbg_ratelimited("%s: Packet has invalid nonce %llu (max %llu)\n", peer->device->dev->name, PACKET_CB(skb)->nonce, - keypair->receiving_counter.counter); + READ_ONCE(keypair->receiving_counter.counter)); goto next; }
Thanks.
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