From: Herbert Xu <herbert@gondor.apana.org.au> stable inclusion from stable-v6.6.108 commit 7c4491b5644e3a3708f3dbd7591be0a570135b84 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/ID1OXK CVE: CVE-2025-39964 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- 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. 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> Signed-off-by: Gu Bowen <gubowen5@huawei.com> --- 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 80e95d0d0c45..886eccb97b04 100644 --- a/crypto/af_alg.c +++ b/crypto/af_alg.c @@ -969,6 +969,12 @@ 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; @@ -1104,6 +1110,7 @@ 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 bb5f20644786..384684b36aaa 100644 --- a/include/crypto/if_alg.h +++ b/include/crypto/if_alg.h @@ -140,6 +140,7 @@ 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. @@ -155,10 +156,11 @@ 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; -- 2.43.0