tipc: fix a potential deadlock on &tx->lock

It seems that tipc_crypto_key_revoke() could be be invoked by wokequeue tipc_crypto_work_rx() under process context and timer/rx callback under softirq context, thus the lock acquisition on &tx->lock seems better use spin_lock_bh() to prevent possible deadlock. This flaw was found by an experimental static analysis tool I am developing for irq-related deadlock. tipc_crypto_work_rx() <workqueue> --> tipc_crypto_key_distr() --> tipc_bcast_xmit() --> tipc_bcbase_xmit() --> tipc_bearer_bc_xmit() --> tipc_crypto_xmit() --> tipc_ehdr_build() --> tipc_crypto_key_revoke() --> spin_lock(&tx->lock) <timer interrupt> --> tipc_disc_timeout() --> tipc_bearer_xmit_skb() --> tipc_crypto_xmit() --> tipc_ehdr_build() --> tipc_crypto_key_revoke() --> spin_lock(&tx->lock) <deadlock here> Signed-off-by: Chengfeng Ye <[email protected]> Reviewed-by: Jacob Keller <[email protected]> Acked-by: Jon Maloy <[email protected]> Fixes: fc1b6d6 ("tipc: introduce TIPC encryption & authentication") Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Jakub Kicinski <[email protected]>
torvalds · Oct 4, 2023 · 08e50cf · 08e50cf
1 parent 6f195d6
commit 08e50cf
Showing 1 changed file with 2 additions and 2 deletions.
diff --git a/net/tipc/crypto.c b/net/tipc/crypto.c
@@ -1441,14 +1441,14 @@ static int tipc_crypto_key_revoke(struct net *net, u8 tx_key)
  struct tipc_crypto *tx = tipc_net(net)->crypto_tx;
  struct tipc_key key;
 
- spin_lock(&tx->lock);
+ spin_lock_bh(&tx->lock);
  key = tx->key;
  WARN_ON(!key.active || tx_key != key.active);
 
  /* Free the active key */
  tipc_crypto_key_set_state(tx, key.passive, 0, key.pending);
  tipc_crypto_key_detach(tx->aead[key.active], &tx->lock);
- spin_unlock(&tx->lock);
+ spin_unlock_bh(&tx->lock);
 
  pr_warn("%s: key is revoked\n", tx->name);
  return -EKEYREVOKED;