From 6f3fc8613133436f948ca38b125bd14650d6afce Mon Sep 17 00:00:00 2001
From: Yu Watanabe <watanabe.yu+github@gmail.com>
Date: Mon, 7 Feb 2022 13:56:36 +0900
Subject: [PATCH] sd-dhcp6-client: do not expose set_transaction_id()

This is mostly for tests or fuzzers. Hence, this makes the function
requires that the client is running in the test mode.

Also, now the function mask the value for message type.
---
 src/libsystemd-network/dhcp6-internal.h         | 1 +
 src/libsystemd-network/fuzz-dhcp6-client-send.c | 2 +-
 src/libsystemd-network/fuzz-dhcp6-client.c      | 2 +-
 src/libsystemd-network/sd-dhcp6-client.c        | 9 ++++++---
 src/systemd/sd-dhcp6-client.h                   | 2 --
 5 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/src/libsystemd-network/dhcp6-internal.h b/src/libsystemd-network/dhcp6-internal.h
index 75bf879540..aefcdc2d36 100644
--- a/src/libsystemd-network/dhcp6-internal.h
+++ b/src/libsystemd-network/dhcp6-internal.h
@@ -173,6 +173,7 @@ const char *dhcp6_message_status_to_string(DHCP6Status s) _const_;
 DHCP6Status dhcp6_message_status_from_string(const char *s) _pure_;
 
 void dhcp6_client_set_test_mode(sd_dhcp6_client *client, bool test_mode);
+int dhcp6_client_set_transaction_id(sd_dhcp6_client *client, uint32_t transaction_id);
 
 #define log_dhcp6_client_errno(client, error, fmt, ...)         \
         log_interface_prefix_full_errno(                        \
diff --git a/src/libsystemd-network/fuzz-dhcp6-client-send.c b/src/libsystemd-network/fuzz-dhcp6-client-send.c
index 906c835b03..16a71e72d3 100644
--- a/src/libsystemd-network/fuzz-dhcp6-client-send.c
+++ b/src/libsystemd-network/fuzz-dhcp6-client-send.c
@@ -39,7 +39,7 @@ int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
         assert_se(sd_dhcp6_client_set_information_request(client, false) == 0);
         dhcp6_client_set_test_mode(client, true);
         assert_se(sd_dhcp6_client_start(client) >= 0);
-        assert_se(sd_dhcp6_client_set_transaction_id(client, htobe32(0x00ffffff) & ((const DHCP6Message *) data)->transaction_id) == 0);
+        assert_se(dhcp6_client_set_transaction_id(client, ((const DHCP6Message *) data)->transaction_id) == 0);
 
         r = client_process_advertise_or_rapid_commit_reply(client, (DHCP6Message *) data, size, NULL, NULL);
         if (r < 0)
diff --git a/src/libsystemd-network/fuzz-dhcp6-client.c b/src/libsystemd-network/fuzz-dhcp6-client.c
index f62ab468df..10dbead21c 100644
--- a/src/libsystemd-network/fuzz-dhcp6-client.c
+++ b/src/libsystemd-network/fuzz-dhcp6-client.c
@@ -38,7 +38,7 @@ static void fuzz_client(const uint8_t *data, size_t size, bool is_information_re
         assert_se(sd_dhcp6_client_start(client) >= 0);
 
         if (size >= sizeof(DHCP6Message))
-                assert_se(sd_dhcp6_client_set_transaction_id(client, htobe32(0x00ffffff) & ((const DHCP6Message *) data)->transaction_id) == 0);
+                assert_se(dhcp6_client_set_transaction_id(client, ((const DHCP6Message *) data)->transaction_id) == 0);
 
         assert_se(write(test_dhcp_fd[1], data, size) == (ssize_t) size);
 
diff --git a/src/libsystemd-network/sd-dhcp6-client.c b/src/libsystemd-network/sd-dhcp6-client.c
index b59dce74a9..1d1e263306 100644
--- a/src/libsystemd-network/sd-dhcp6-client.c
+++ b/src/libsystemd-network/sd-dhcp6-client.c
@@ -592,10 +592,13 @@ int sd_dhcp6_client_set_address_request(sd_dhcp6_client *client, int request) {
         return 0;
 }
 
-int sd_dhcp6_client_set_transaction_id(sd_dhcp6_client *client, uint32_t transaction_id) {
-        assert_return(client, -EINVAL);
+int dhcp6_client_set_transaction_id(sd_dhcp6_client *client, uint32_t transaction_id) {
+        assert(client);
+        assert(client->test_mode);
 
-        client->transaction_id = transaction_id;
+        /* This is for tests or fuzzers. */
+
+        client->transaction_id = transaction_id & htobe32(0x00ffffff);
 
         return 0;
 }
diff --git a/src/systemd/sd-dhcp6-client.h b/src/systemd/sd-dhcp6-client.h
index d857af5acf..1bb21e0255 100644
--- a/src/systemd/sd-dhcp6-client.h
+++ b/src/systemd/sd-dhcp6-client.h
@@ -260,8 +260,6 @@ int sd_dhcp6_client_get_address_request(sd_dhcp6_client *client,
                                         int *request);
 int sd_dhcp6_client_set_address_request(sd_dhcp6_client *client,
                                         int request);
-int sd_dhcp6_client_set_transaction_id(sd_dhcp6_client *client,
-                                       uint32_t transaction_id);
 int sd_dhcp6_client_add_vendor_option(sd_dhcp6_client *client,
                                       sd_dhcp6_option *v);