Merge branch 'tls-splice-hint-fixes'

John Fastabend says:

====================
tls fixes for SPLICE with more hint

Syzbot found a splat where it tried to splice data over a tls socket
with the more hint and sending greater than the number of frags that
fit in a msg scatterlist. This resulted in an error where we do not
correctly send the data when the msg sg is full. The more flag being
just a hint not a strict contract. This then results in the syzbot
warning on the next send.

Edward generated an initial patch for this which checked for a full
msg on entry to the sendmsg hook.  This fixed the WARNING, but didn't
fully resolve the issue because the full msg_pl scatterlist was never
sent resulting in a stuck socket. In this series instead avoid the
situation by forcing the send on the splice that fills the scatterlist.

Also in original thread I mentioned it didn't seem to be enough to
simply fix the send on full sg problem. That was incorrect and was
really a bug in my test program that was hanging the test program.
I had setup a repair socket and wasn't handling it correctly so my
tester got stuck.

Thanks. Please review. Fix in patch 1 and test in patch 2.

v2: use SPLICE_F_ flag names instead of cryptic 0xe
====================

Signed-off-by: David S. Miller <[email protected]>

net/tls/tls_sw.c

@@ -1052,7 +1052,11 @@ static int tls_sw_sendmsg_locked(struct sock *sk, struct msghdr *msg,
 			if (ret < 0)
 				goto send_end;
 			tls_ctx->pending_open_record_frags = true;
-			if (full_record || eor || sk_msg_full(msg_pl))
+
+			if (sk_msg_full(msg_pl))
+				full_record = true;
+
+			if (full_record || eor)
 				goto copied;
 			continue;
 		}

tools/testing/selftests/net/tls.c

@@ -707,6 +707,20 @@ TEST_F(tls, splice_from_pipe)
 	EXPECT_EQ(memcmp(mem_send, mem_recv, send_len), 0);
 }
 
+TEST_F(tls, splice_more)
+{
+	unsigned int f = SPLICE_F_NONBLOCK | SPLICE_F_MORE | SPLICE_F_GIFT;
+	int send_len = TLS_PAYLOAD_MAX_LEN;
+	char mem_send[TLS_PAYLOAD_MAX_LEN];
+	int i, send_pipe = 1;
+	int p[2];
+
+	ASSERT_GE(pipe(p), 0);
+	EXPECT_GE(write(p[1], mem_send, send_len), 0);
+	for (i = 0; i < 32; i++)
+		EXPECT_EQ(splice(p[0], NULL, self->fd, NULL, send_pipe, f), 1);
+}
+
 TEST_F(tls, splice_from_pipe2)
 {
 	int send_len = 16000;