Patch "crypto: af_alg - Disallow multiple in-flight AIO requests" has been added to the 4.19-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    crypto: af_alg - Disallow multiple in-flight AIO requests

to the 4.19-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     crypto-af_alg-disallow-multiple-in-flight-aio-reques.patch
and it can be found in the queue-4.19 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit b0141b7d80f658bc7ddaba3d49db270f797cbf59
Author: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Date:   Tue Nov 28 16:25:49 2023 +0800

    crypto: af_alg - Disallow multiple in-flight AIO requests
    
    [ Upstream commit 67b164a871af1d736f131fd6fe78a610909f06f3 ]
    
    Having multiple in-flight AIO requests results in unpredictable
    output because they all share the same IV.  Fix this by only allowing
    one request at a time.
    
    Fixes: 83094e5e9e49 ("crypto: af_alg - add async support to algif_aead")
    Fixes: a596999b7ddf ("crypto: algif - change algif_skcipher to be asynchronous")
    Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/crypto/af_alg.c b/crypto/af_alg.c
index d0276a4ed987..914496b184a9 100644
--- a/crypto/af_alg.c
+++ b/crypto/af_alg.c
@@ -1032,9 +1032,13 @@ EXPORT_SYMBOL_GPL(af_alg_sendpage);
 void af_alg_free_resources(struct af_alg_async_req *areq)
 {
 	struct sock *sk = areq->sk;
+	struct af_alg_ctx *ctx;
 
 	af_alg_free_areq_sgls(areq);
 	sock_kfree_s(sk, areq, areq->areqlen);
+
+	ctx = alg_sk(sk)->private;
+	ctx->inflight = false;
 }
 EXPORT_SYMBOL_GPL(af_alg_free_resources);
 
@@ -1098,11 +1102,19 @@ EXPORT_SYMBOL_GPL(af_alg_poll);
 struct af_alg_async_req *af_alg_alloc_areq(struct sock *sk,
 					   unsigned int areqlen)
 {
-	struct af_alg_async_req *areq = sock_kmalloc(sk, areqlen, GFP_KERNEL);
+	struct af_alg_ctx *ctx = alg_sk(sk)->private;
+	struct af_alg_async_req *areq;
+
+	/* Only one AIO request can be in flight. */
+	if (ctx->inflight)
+		return ERR_PTR(-EBUSY);
 
+	areq = sock_kmalloc(sk, areqlen, GFP_KERNEL);
 	if (unlikely(!areq))
 		return ERR_PTR(-ENOMEM);
 
+	ctx->inflight = true;
+
 	areq->areqlen = areqlen;
 	areq->sk = sk;
 	areq->last_rsgl = NULL;
diff --git a/include/crypto/if_alg.h b/include/crypto/if_alg.h
index 11f107df78dc..2c1748dc6640 100644
--- a/include/crypto/if_alg.h
+++ b/include/crypto/if_alg.h
@@ -141,6 +141,7 @@ struct af_alg_async_req {
  * @enc:		Cryptographic operation to be performed when
  *			recvmsg is invoked.
  * @len:		Length of memory allocated for this data structure.
+ * @inflight:		Non-zero when AIO requests are in flight.
  */
 struct af_alg_ctx {
 	struct list_head tsgl_list;
@@ -158,6 +159,8 @@ struct af_alg_ctx {
 	bool enc;
 
 	unsigned int len;
+
+	unsigned int inflight;
 };
 
 int af_alg_register_type(const struct af_alg_type *type);