From 11edb555966ed2c66c533d17c604f9d7e580a829 Mon Sep 17 00:00:00 2001 From: Stephan Mueller Date: Wed, 29 Nov 2017 12:02:23 +0100 Subject: crypto: af_alg - wait for data at beginning of recvmsg The wait for data is a non-atomic operation that can sleep and therefore potentially release the socket lock. The release of the socket lock allows another thread to modify the context data structure. The waiting operation for new data therefore must be called at the beginning of recvmsg. This prevents a race condition where checks of the members of the context data structure are performed by recvmsg while there is a potential for modification of these values. Fixes: e870456d8e7c ("crypto: algif_skcipher - overhaul memory management") Fixes: d887c52d6ae4 ("crypto: algif_aead - overhaul memory management") Reported-by: syzbot Cc: # v4.14+ Signed-off-by: Stephan Mueller Signed-off-by: Herbert Xu --- crypto/algif_aead.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'crypto/algif_aead.c') diff --git a/crypto/algif_aead.c b/crypto/algif_aead.c index 805f485ddf1b..c8a32bef208a 100644 --- a/crypto/algif_aead.c +++ b/crypto/algif_aead.c @@ -111,6 +111,12 @@ static int _aead_recvmsg(struct socket *sock, struct msghdr *msg, size_t usedpages = 0; /* [in] RX bufs to be used from user */ size_t processed = 0; /* [in] TX bufs to be consumed */ + if (!ctx->used) { + err = af_alg_wait_for_data(sk, flags); + if (err) + return err; + } + /* * Data length provided by caller via sendmsg/sendpage that has not * yet been processed. -- cgit v1.2.1 From d53c5135792319e095bb126bc43b2ee98586f7fe Mon Sep 17 00:00:00 2001 From: Stephan Mueller Date: Fri, 8 Dec 2017 11:50:37 +0100 Subject: crypto: af_alg - fix race accessing cipher request 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 Cc: # v4.14+ Signed-off-by: Stephan Mueller Acked-by: Jonathan Cameron Signed-off-by: Herbert Xu --- crypto/algif_aead.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'crypto/algif_aead.c') diff --git a/crypto/algif_aead.c b/crypto/algif_aead.c index c8a32bef208a..b73db2b27656 100644 --- 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 { -- cgit v1.2.1