From: Herbert Xu herbert@gondor.apana.org.au
[ Upstream commit 1b34cbbf4f011a121ef7b2d7d6e6920a036d5285 ]
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.
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: Sasha Levin sashal@kernel.org --- crypto/af_alg.c | 7 +++++++ include/crypto/if_alg.h | 10 ++++++---- 2 files changed, 13 insertions(+), 4 deletions(-)
diff --git a/crypto/af_alg.c b/crypto/af_alg.c index 303225c674558..cd3f0a625fb19 100644 --- a/crypto/af_alg.c +++ b/crypto/af_alg.c @@ -859,6 +859,12 @@ 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 a406e281ae571..1424200fe88cf 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;