From 7d2c3f54e6f646887d019faa45f35d6fe9fe82ce Mon Sep 17 00:00:00 2001 From: Stephan Mueller Date: Fri, 10 Nov 2017 13:20:55 +0100 Subject: crypto: af_alg - remove locking in async callback The code paths protected by the socket-lock do not use or modify the socket in a non-atomic fashion. The actions pertaining the socket do not even need to be handled as an atomic operation. Thus, the socket-lock can be safely ignored. This fixes a bug regarding scheduling in atomic as the callback function may be invoked in interrupt context. In addition, the sock_hold is moved before the AIO encrypt/decrypt operation to ensure that the socket is always present. This avoids a tiny race window where the socket is unprotected and yet used by the AIO operation. Finally, the release of resources for a crypto operation is moved into a common function of af_alg_free_resources. Cc: Fixes: e870456d8e7c8 ("crypto: algif_skcipher - overhaul memory management") Fixes: d887c52d6ae43 ("crypto: algif_aead - overhaul memory management") Reported-by: Romain Izard Signed-off-by: Stephan Mueller Tested-by: Romain Izard Signed-off-by: Herbert Xu --- crypto/af_alg.c | 21 ++++++++++++++------- 1 file changed, 14 insertions(+), 7 deletions(-) (limited to 'crypto/af_alg.c') diff --git a/crypto/af_alg.c b/crypto/af_alg.c index 85cea9de324a..358749c38894 100644 --- a/crypto/af_alg.c +++ b/crypto/af_alg.c @@ -1020,6 +1020,18 @@ unlock: } EXPORT_SYMBOL_GPL(af_alg_sendpage); +/** + * af_alg_free_resources - release resources required for crypto request + */ +void af_alg_free_resources(struct af_alg_async_req *areq) +{ + struct sock *sk = areq->sk; + + af_alg_free_areq_sgls(areq); + sock_kfree_s(sk, areq, areq->areqlen); +} +EXPORT_SYMBOL_GPL(af_alg_free_resources); + /** * af_alg_async_cb - AIO callback handler * @@ -1036,18 +1048,13 @@ void af_alg_async_cb(struct crypto_async_request *_req, int err) struct kiocb *iocb = areq->iocb; unsigned int resultlen; - lock_sock(sk); - /* Buffer size written by crypto operation. */ resultlen = areq->outlen; - af_alg_free_areq_sgls(areq); - sock_kfree_s(sk, areq, areq->areqlen); - __sock_put(sk); + af_alg_free_resources(areq); + sock_put(sk); iocb->ki_complete(iocb, err ? err : resultlen, 0); - - release_sock(sk); } EXPORT_SYMBOL_GPL(af_alg_async_cb); -- cgit