From: Yu Watanabe <watanabe.yu+github@gmail.com>
Date: Mon, 7 Feb 2022 15:30:56 +0000 (+0900)
Subject: fuzz-dhcp6-client: test multiple states
X-Git-Tag: v251-rc1~291^2~4
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=013c6904fa5cf214c7cecf144d84b93514072ed0;p=thirdparty%2Fsystemd.git

fuzz-dhcp6-client: test multiple states

Then, now all three paths client_process_information(),
client_process_reply(), and client_process_advertise_or_rapid_commit_reply()
in client_receive_message() are fuzzed.
---

diff --git a/src/libsystemd-network/fuzz-dhcp6-client.c b/src/libsystemd-network/fuzz-dhcp6-client.c
index 10dbead21ca..ad676e67444 100644
--- a/src/libsystemd-network/fuzz-dhcp6-client.c
+++ b/src/libsystemd-network/fuzz-dhcp6-client.c
@@ -6,43 +6,49 @@
 #include "sd-event.h"
 
 #include "dhcp6-internal.h"
-#include "dhcp6-protocol.h"
+#include "event-util.h"
 #include "fd-util.h"
 #include "fuzz.h"
 
 static int test_dhcp_fd[2] = { -1, -1 };
 
-int dhcp6_network_send_udp_socket(int s, struct in6_addr *server_address,
-                                  const void *packet, size_t len) {
+int dhcp6_network_send_udp_socket(int s, struct in6_addr *server_address, const void *packet, size_t len) {
         return len;
 }
 
 int dhcp6_network_bind_udp_socket(int index, struct in6_addr *local_address) {
         assert_se(socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC | SOCK_NONBLOCK, 0, test_dhcp_fd) >= 0);
-        return test_dhcp_fd[0];
+        return TAKE_FD(test_dhcp_fd[0]);
 }
 
-static void fuzz_client(const uint8_t *data, size_t size, bool is_information_request_enabled) {
-        _cleanup_(sd_event_unrefp) sd_event *e = NULL;
-        _cleanup_(sd_dhcp6_client_unrefp) sd_dhcp6_client *client = NULL;
-        struct in6_addr address = { { { 0xfe, 0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x01 } } };
-
-        assert_se(sd_event_new(&e) >= 0);
-        assert_se(sd_dhcp6_client_new(&client) >= 0);
-        assert_se(sd_dhcp6_client_attach_event(client, e, 0) >= 0);
-        assert_se(sd_dhcp6_client_set_ifindex(client, 42) == 0);
-        assert_se(sd_dhcp6_client_set_local_address(client, &address) >= 0);
-        assert_se(sd_dhcp6_client_set_information_request(client, is_information_request_enabled) == 0);
-        dhcp6_client_set_test_mode(client, true);
-
+static void fuzz_client(sd_dhcp6_client *client, const uint8_t *data, size_t size, DHCP6State state) {
+        assert_se(sd_dhcp6_client_set_information_request(client, state == DHCP6_STATE_INFORMATION_REQUEST) >= 0);
         assert_se(sd_dhcp6_client_start(client) >= 0);
 
+        client->state = state;
+
         if (size >= sizeof(DHCP6Message))
                 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);
 
-        sd_event_run(e, UINT64_MAX);
+        assert_se(sd_event_run(sd_dhcp6_client_get_event(client), UINT64_MAX) > 0);
+
+        /* Check the state transition. */
+        if (client->state != state)
+                switch (state) {
+                case DHCP6_STATE_INFORMATION_REQUEST:
+                        assert_se(client->state == DHCP6_STATE_STOPPED);
+                        break;
+                case DHCP6_STATE_SOLICITATION:
+                        assert_se(IN_SET(client->state, DHCP6_STATE_REQUEST, DHCP6_STATE_BOUND));
+                        break;
+                case DHCP6_STATE_REQUEST:
+                        assert_se(client->state == DHCP6_STATE_BOUND);
+                        break;
+                default:
+                        assert_not_reached();
+                }
 
         assert_se(sd_dhcp6_client_stop(client) >= 0);
 
@@ -50,14 +56,29 @@ static void fuzz_client(const uint8_t *data, size_t size, bool is_information_re
 }
 
 int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
+        _cleanup_(sd_event_unrefp) sd_event *e = NULL;
+        _cleanup_(sd_dhcp6_client_unrefp) sd_dhcp6_client *client = NULL;
+        struct in6_addr address = { { { 0xfe, 0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0x01 } } };
+
         if (size > 65536)
                 return 0;
 
-        /* This triggers client_receive_advertise */
-        fuzz_client(data, size, false);
+        assert_se(sd_event_new(&e) >= 0);
+        assert_se(sd_dhcp6_client_new(&client) >= 0);
+        assert_se(sd_dhcp6_client_attach_event(client, e, 0) >= 0);
+        assert_se(sd_dhcp6_client_set_ifindex(client, 42) >= 0);
+        assert_se(sd_dhcp6_client_set_local_address(client, &address) >= 0);
+        dhcp6_client_set_test_mode(client, true);
+
+        fuzz_client(client, data, size, DHCP6_STATE_INFORMATION_REQUEST);
+        fuzz_client(client, data, size, DHCP6_STATE_SOLICITATION);
+
+        /* If size is zero, then the resend timer will be triggered at first,
+         * but in the REQUEST state the client must have a lease. */
+        if (size == 0)
+                return 0;
 
-        /* This triggers client_receive_reply */
-        fuzz_client(data, size, true);
+        fuzz_client(client, data, size, DHCP6_STATE_REQUEST);
 
         return 0;
 }