diff mbox series

crypto: af_alg - Work around empty control messages without MSG_MORE

Message ID 20200826132952.GA4752@gondor.apana.org.au
State Accepted
Commit c195d66a8a75c60515819b101975f38b7ec6577f
Headers show
Series crypto: af_alg - Work around empty control messages without MSG_MORE | expand

Commit Message

Herbert Xu Aug. 26, 2020, 1:29 p.m. UTC 
The iwd daemon uses libell which sets up the skcipher operation with
two separate control messages.  This is fine by itself but the first
control message is sent without MSG_MORE.  This means that the first
control message is interpreted as an empty request.

While libell should be fixed to use MSG_MORE where appropriate, this
patch works around the bug in the kernel so that existing binaries
continue to work.

We will print a warning however.

Reported-by: Caleb Jorden <caljorden@hotmail.com>
Fixes: f3c802a1f300 ("crypto: algif_aead - Only wake up when...")
Cc: <stable@vger.kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
diff mbox series

Patch

diff --git a/crypto/af_alg.c b/crypto/af_alg.c
index a6f581ab200c..3da21cadc326 100644
--- a/crypto/af_alg.c
+++ b/crypto/af_alg.c
@@ -16,6 +16,7 @@ 
 #include <linux/module.h>
 #include <linux/net.h>
 #include <linux/rwsem.h>
+#include <linux/sched.h>
 #include <linux/sched/signal.h>
 #include <linux/security.h>
 
@@ -846,8 +847,14 @@  int af_alg_sendmsg(struct socket *sock, struct msghdr *msg, size_t size,
 
 	lock_sock(sk);
 	if (ctx->init && (init || !ctx->more)) {
-		err = -EINVAL;
-		goto unlock;
+		if (ctx->used) {
+			err = -EINVAL;
+			goto unlock;
+		}
+
+		pr_info_once(
+			"%s sent an empty control message without MSG_MORE.\n",
+			current->comm);
 	}
 	ctx->init = true;