crypto: af_alg - remove locking in async callback
commit 7d2c3f54e6f646887d019faa45f35d6fe9fe82ce upstream.
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.
Fixes: e870456d8e7c8 ("crypto: algif_skcipher - overhaul memory management")
Fixes: d887c52d6ae43 ("crypto: algif_aead - overhaul memory management")
Reported-by: Romain Izard <romain.izard.pro@gmail.com>
Signed-off-by: Stephan Mueller <smueller@chronox.de>
Tested-by: Romain Izard <romain.izard.pro@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/crypto/af_alg.c b/crypto/af_alg.c
index 337cf38..a72659f 100644
--- a/crypto/af_alg.c
+++ b/crypto/af_alg.c
@@ -1048,6 +1048,18 @@
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
*
* This handler cleans up the struct af_alg_async_req upon completion of the
@@ -1063,18 +1075,13 @@
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);