Merge branch 'tls-fixes-for-record-type-handling-with-peek'

Sabrina Dubroca says:

====================
tls: fixes for record type handling with PEEK

There are multiple bugs in tls_sw_recvmsg's handling of record types
when MSG_PEEK flag is used, which can lead to incorrectly merging two
records:
 - consecutive non-DATA records shouldn't be merged, even if they're
   the same type (partly handled by the test at the end of the main
   loop)
 - records of the same type (even DATA) shouldn't be merged if one
   record of a different type comes in between
====================

Link: https://lore.kernel.org/r/cover.1708007371.git.sd@queasysnail.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net/tls/tls_sw.c

@@ -1772,7 +1772,8 @@ static int process_rx_list(struct tls_sw_context_rx *ctx,
 			   u8 *control,
 			   size_t skip,
 			   size_t len,
-			   bool is_peek)
+			   bool is_peek,
+			   bool *more)
 {
 	struct sk_buff *skb = skb_peek(&ctx->rx_list);
 	struct tls_msg *tlm;
@@ -1785,7 +1786,7 @@ static int process_rx_list(struct tls_sw_context_rx *ctx,
 
 		err = tls_record_content_type(msg, tlm, control);
 		if (err <= 0)
-			goto out;
+			goto more;
 
 		if (skip < rxm->full_len)
 			break;
@@ -1803,12 +1804,12 @@ static int process_rx_list(struct tls_sw_context_rx *ctx,
 
 		err = tls_record_content_type(msg, tlm, control);
 		if (err <= 0)
-			goto out;
+			goto more;
 
 		err = skb_copy_datagram_msg(skb, rxm->offset + skip,
 					    msg, chunk);
 		if (err < 0)
-			goto out;
+			goto more;
 
 		len = len - chunk;
 		copied = copied + chunk;
@@ -1844,6 +1845,10 @@ static int process_rx_list(struct tls_sw_context_rx *ctx,
 
 out:
 	return copied ? : err;
+more:
+	if (more)
+		*more = true;
+	goto out;
 }
 
 static bool
@@ -1947,6 +1952,7 @@ int tls_sw_recvmsg(struct sock *sk,
 	int target, err;
 	bool is_kvec = iov_iter_is_kvec(&msg->msg_iter);
 	bool is_peek = flags & MSG_PEEK;
+	bool rx_more = false;
 	bool released = true;
 	bool bpf_strp_enabled;
 	bool zc_capable;
@@ -1966,12 +1972,12 @@ int tls_sw_recvmsg(struct sock *sk,
 		goto end;
 
 	/* Process pending decrypted records. It must be non-zero-copy */
-	err = process_rx_list(ctx, msg, &control, 0, len, is_peek);
+	err = process_rx_list(ctx, msg, &control, 0, len, is_peek, &rx_more);
 	if (err < 0)
 		goto end;
 
 	copied = err;
-	if (len <= copied)
+	if (len <= copied || (copied && control != TLS_RECORD_TYPE_DATA) || rx_more)
 		goto end;
 
 	target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
@@ -2064,6 +2070,8 @@ put_on_rx_list:
 				decrypted += chunk;
 				len -= chunk;
 				__skb_queue_tail(&ctx->rx_list, skb);
+				if (unlikely(control != TLS_RECORD_TYPE_DATA))
+					break;
 				continue;
 			}
 
@@ -2128,10 +2136,10 @@ recv_end:
 		/* Drain records from the rx_list & copy if required */
 		if (is_peek || is_kvec)
 			err = process_rx_list(ctx, msg, &control, copied,
-					      decrypted, is_peek);
+					      decrypted, is_peek, NULL);
 		else
 			err = process_rx_list(ctx, msg, &control, 0,
-					      async_copy_bytes, is_peek);
+					      async_copy_bytes, is_peek, NULL);
 	}
 
 	copied += decrypted;

tools/testing/selftests/net/tls.c

@@ -1485,6 +1485,51 @@ TEST_F(tls, control_msg)
 	EXPECT_EQ(memcmp(buf, test_str, send_len), 0);
 }
 
+TEST_F(tls, control_msg_nomerge)
+{
+	char *rec1 = "1111";
+	char *rec2 = "2222";
+	int send_len = 5;
+	char buf[15];
+
+	if (self->notls)
+		SKIP(return, "no TLS support");
+
+	EXPECT_EQ(tls_send_cmsg(self->fd, 100, rec1, send_len, 0), send_len);
+	EXPECT_EQ(tls_send_cmsg(self->fd, 100, rec2, send_len, 0), send_len);
+
+	EXPECT_EQ(tls_recv_cmsg(_metadata, self->cfd, 100, buf, sizeof(buf), MSG_PEEK), send_len);
+	EXPECT_EQ(memcmp(buf, rec1, send_len), 0);
+
+	EXPECT_EQ(tls_recv_cmsg(_metadata, self->cfd, 100, buf, sizeof(buf), MSG_PEEK), send_len);
+	EXPECT_EQ(memcmp(buf, rec1, send_len), 0);
+
+	EXPECT_EQ(tls_recv_cmsg(_metadata, self->cfd, 100, buf, sizeof(buf), 0), send_len);
+	EXPECT_EQ(memcmp(buf, rec1, send_len), 0);
+
+	EXPECT_EQ(tls_recv_cmsg(_metadata, self->cfd, 100, buf, sizeof(buf), 0), send_len);
+	EXPECT_EQ(memcmp(buf, rec2, send_len), 0);
+}
+
+TEST_F(tls, data_control_data)
+{
+	char *rec1 = "1111";
+	char *rec2 = "2222";
+	char *rec3 = "3333";
+	int send_len = 5;
+	char buf[15];
+
+	if (self->notls)
+		SKIP(return, "no TLS support");
+
+	EXPECT_EQ(send(self->fd, rec1, send_len, 0), send_len);
+	EXPECT_EQ(tls_send_cmsg(self->fd, 100, rec2, send_len, 0), send_len);
+	EXPECT_EQ(send(self->fd, rec3, send_len, 0), send_len);
+
+	EXPECT_EQ(recv(self->cfd, buf, sizeof(buf), MSG_PEEK), send_len);
+	EXPECT_EQ(recv(self->cfd, buf, sizeof(buf), MSG_PEEK), send_len);
+}
+
 TEST_F(tls, shutdown)
 {
 	char const *test_str = "test_read";