From: Xin Long lucien.xin@gmail.com
[ Upstream commit f6db9096416209474090d64d8284e7c16c3d8873 ]
b->media->send_msg() requires rcu_read_lock(), as we can see elsewhere in tipc, tipc_bearer_xmit, tipc_bearer_xmit_skb and tipc_bearer_bc_xmit().
Syzbot has reported this issue as:
net/tipc/bearer.c:466 suspicious rcu_dereference_check() usage! Workqueue: cryptd cryptd_queue_worker Call Trace: tipc_l2_send_msg+0x354/0x420 net/tipc/bearer.c:466 tipc_aead_encrypt_done+0x204/0x3a0 net/tipc/crypto.c:761 cryptd_aead_crypt+0xe8/0x1d0 crypto/cryptd.c:739 cryptd_queue_worker+0x118/0x1b0 crypto/cryptd.c:181 process_one_work+0x94c/0x1670 kernel/workqueue.c:2269 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415 kthread+0x3b5/0x4a0 kernel/kthread.c:291 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293
So fix it by calling rcu_read_lock() in tipc_aead_encrypt_done() for b->media->send_msg().
Fixes: fc1b6d6de220 ("tipc: introduce TIPC encryption & authentication") Reported-by: syzbot+47bbc6b678d317cccbe0@syzkaller.appspotmail.com Signed-off-by: Xin Long lucien.xin@gmail.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/tipc/crypto.c | 2 ++ 1 file changed, 2 insertions(+)
--- a/net/tipc/crypto.c +++ b/net/tipc/crypto.c @@ -757,10 +757,12 @@ static void tipc_aead_encrypt_done(struc switch (err) { case 0: this_cpu_inc(tx->stats->stat[STAT_ASYNC_OK]); + rcu_read_lock(); if (likely(test_bit(0, &b->up))) b->media->send_msg(net, skb, b, &tx_ctx->dst); else kfree_skb(skb); + rcu_read_unlock(); break; case -EINPROGRESS: return;