UPSTREAM: crypto: af_alg - Disallow concurrent writes in af_alg_sendmsg
commit 1b34cbbf4f011a121ef7b2d7d6e6920a036d5285 upstream.
Issuing two writes to the same af_alg socket is bogus as the
data will be interleaved in an unpredictable fashion. Furthermore,
concurrent writes may create inconsistencies in the internal
socket state.
Disallow this by adding a new ctx->write field that indiciates
exclusive ownership for writing.
Bug: 446278751
Fixes: 8ff590903d5 ("crypto: algif_skcipher - User-space interface for skcipher operations")
Reported-by: Muhammad Alifa Ramdhan <ramdhan@starlabs.sg>
Reported-by: Bing-Jhong Billy Jheng <billy@starlabs.sg>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit 9aee87da5572b3a14075f501752e209801160d3d)
Signed-off-by: Lee Jones <joneslee@google.com>
Change-Id: Ie4b99c532ab77a6e25483ece1f42ed4c4744e70f
diff --git a/crypto/af_alg.c b/crypto/af_alg.c
index 755e6ca..25cf2fa 100644
--- a/crypto/af_alg.c
+++ b/crypto/af_alg.c
@@ -862,6 +862,12 @@ int af_alg_sendmsg(struct socket *sock, struct msghdr *msg, size_t size,
}
lock_sock(sk);
+ if (ctx->write) {
+ release_sock(sk);
+ return -EBUSY;
+ }
+ ctx->write = true;
+
if (ctx->init && !ctx->more) {
if (ctx->used) {
err = -EINVAL;
@@ -969,6 +975,7 @@ int af_alg_sendmsg(struct socket *sock, struct msghdr *msg, size_t size,
unlock:
af_alg_data_wakeup(sk);
+ ctx->write = false;
release_sock(sk);
return copied ?: err;
diff --git a/include/crypto/if_alg.h b/include/crypto/if_alg.h
index a406e28..1424200f 100644
--- a/include/crypto/if_alg.h
+++ b/include/crypto/if_alg.h
@@ -136,6 +136,7 @@ struct af_alg_async_req {
* SG?
* @enc: Cryptographic operation to be performed when
* recvmsg is invoked.
+ * @write: True if we are in the middle of a write.
* @init: True if metadata has been sent.
* @len: Length of memory allocated for this data structure.
* @inflight: Non-zero when AIO requests are in flight.
@@ -151,10 +152,11 @@ struct af_alg_ctx {
size_t used;
atomic_t rcvused;
- bool more;
- bool merge;
- bool enc;
- bool init;
+ u32 more:1,
+ merge:1,
+ enc:1,
+ write:1,
+ init:1;
unsigned int len;
