crypto: af_alg - fix race accessing cipher request

commit d53c5135792319e095bb126bc43b2ee98586f7fe upstream.

When invoking an asynchronous cipher operation, the invocation of the
callback may be performed before the subsequent operations in the
initial code path are invoked. The callback deletes the cipher request
data structure which implies that after the invocation of the
asynchronous cipher operation, this data structure must not be accessed
any more.

The setting of the return code size with the request data structure must
therefore be moved before the invocation of the asynchronous cipher
operation.

Fixes: e870456d8e7c ("crypto: algif_skcipher - overhaul memory management")
Fixes: d887c52d6ae4 ("crypto: algif_aead - overhaul memory management")
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Stephan Mueller <smueller@chronox.de>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/crypto/algif_aead.c b/crypto/algif_aead.c
index ba07da8..782cb8f 100644 (file)
--- a/crypto/algif_aead.c
+++ b/crypto/algif_aead.c
@@ -291,6 +291,10 @@ static int _aead_recvmsg(struct socket *sock, struct msghdr *msg,
                /* AIO operation */
                sock_hold(sk);
                areq->iocb = msg->msg_iocb;
+
+               /* Remember output size that will be generated. */
+               areq->outlen = outlen;
+
                aead_request_set_callback(&areq->cra_u.aead_req,
                                          CRYPTO_TFM_REQ_MAY_BACKLOG,
                                          af_alg_async_cb, areq);
@@ -298,12 +302,8 @@ static int _aead_recvmsg(struct socket *sock, struct msghdr *msg,
                                 crypto_aead_decrypt(&areq->cra_u.aead_req);
 
                /* AIO operation in progress */
-               if (err == -EINPROGRESS || err == -EBUSY) {
-                       /* Remember output size that will be generated. */
-                       areq->outlen = outlen;
-
+               if (err == -EINPROGRESS || err == -EBUSY)
                        return -EIOCBQUEUED;
-               }
 
                sock_put(sk);
        } else {

diff --git a/crypto/algif_skcipher.c b/crypto/algif_skcipher.c
index 3f4458f..7a3e663 100644 (file)
--- a/crypto/algif_skcipher.c
+++ b/crypto/algif_skcipher.c
@@ -125,6 +125,10 @@ static int _skcipher_recvmsg(struct socket *sock, struct msghdr *msg,
                /* AIO operation */
                sock_hold(sk);
                areq->iocb = msg->msg_iocb;
+
+               /* Remember output size that will be generated. */
+               areq->outlen = len;
+
                skcipher_request_set_callback(&areq->cra_u.skcipher_req,
                                              CRYPTO_TFM_REQ_MAY_SLEEP,
                                              af_alg_async_cb, areq);
@@ -133,12 +137,8 @@ static int _skcipher_recvmsg(struct socket *sock, struct msghdr *msg,
                        crypto_skcipher_decrypt(&areq->cra_u.skcipher_req);
 
                /* AIO operation in progress */
-               if (err == -EINPROGRESS || err == -EBUSY) {
-                       /* Remember output size that will be generated. */
-                       areq->outlen = len;
-
+               if (err == -EINPROGRESS || err == -EBUSY)
                        return -EIOCBQUEUED;
-               }
 
                sock_put(sk);
        } else {