From 8b50b3198b40524be6f55301479bdf0115bc30c5 Mon Sep 17 00:00:00 2001
From: Yu Watanabe <watanabe.yu+github@gmail.com>
Date: Fri, 6 Oct 2023 13:22:04 +0900
Subject: [PATCH 1/2] libsystemd-network: introduce $SYSTEMD_NETWORK_TEST_MODE
 environment variable

Then, drop dhcp_client_set_test_mode() and friends.
---
 src/libsystemd-network/dhcp-identifier.c   |  6 +++++-
 src/libsystemd-network/dhcp-identifier.h   |  2 +-
 src/libsystemd-network/dhcp-internal.h     |  2 --
 src/libsystemd-network/dhcp6-internal.h    |  4 ----
 src/libsystemd-network/fuzz-dhcp-client.c  |  3 ++-
 src/libsystemd-network/fuzz-dhcp6-client.c |  3 ++-
 src/libsystemd-network/network-common.c    | 19 +++++++++++++++++++
 src/libsystemd-network/network-common.h    |  2 ++
 src/libsystemd-network/sd-dhcp-client.c    | 11 +----------
 src/libsystemd-network/sd-dhcp6-client.c   | 12 +++---------
 src/libsystemd-network/test-dhcp-client.c  |  6 +++---
 src/libsystemd-network/test-dhcp6-client.c |  8 ++++++--
 12 files changed, 44 insertions(+), 34 deletions(-)

diff --git a/src/libsystemd-network/dhcp-identifier.c b/src/libsystemd-network/dhcp-identifier.c
index c905704ab5e..f65cdbecde5 100644
--- a/src/libsystemd-network/dhcp-identifier.c
+++ b/src/libsystemd-network/dhcp-identifier.c
@@ -6,6 +6,7 @@
 
 #include "dhcp-identifier.h"
 #include "netif-util.h"
+#include "network-common.h"
 #include "siphash24.h"
 #include "sparse-endian.h"
 #include "string-table.h"
@@ -90,14 +91,17 @@ int dhcp_identifier_set_duid_ll(
         return 0;
 }
 
-int dhcp_identifier_set_duid_en(bool test_mode, struct duid *ret_duid, size_t *ret_len) {
+int dhcp_identifier_set_duid_en(struct duid *ret_duid, size_t *ret_len) {
         sd_id128_t machine_id;
+        bool test_mode;
         uint64_t hash;
         int r;
 
         assert(ret_duid);
         assert(ret_len);
 
+        test_mode = network_test_mode_enabled();
+
         if (!test_mode) {
                 r = sd_id128_get_machine(&machine_id);
                 if (r < 0)
diff --git a/src/libsystemd-network/dhcp-identifier.h b/src/libsystemd-network/dhcp-identifier.h
index 7b36f92e7fa..5ffa38dfc8b 100644
--- a/src/libsystemd-network/dhcp-identifier.h
+++ b/src/libsystemd-network/dhcp-identifier.h
@@ -70,7 +70,7 @@ int dhcp_identifier_set_duid_ll(
                 uint16_t arp_type,
                 struct duid *ret_duid,
                 size_t *ret_len);
-int dhcp_identifier_set_duid_en(bool test_mode, struct duid *ret_duid, size_t *ret_len);
+int dhcp_identifier_set_duid_en(struct duid *ret_duid, size_t *ret_len);
 int dhcp_identifier_set_duid_uuid(struct duid *ret_duid, size_t *ret_len);
 int dhcp_identifier_set_duid_raw(
                 DUIDType duid_type,
diff --git a/src/libsystemd-network/dhcp-internal.h b/src/libsystemd-network/dhcp-internal.h
index d4e4a026b52..b027b6faf05 100644
--- a/src/libsystemd-network/dhcp-internal.h
+++ b/src/libsystemd-network/dhcp-internal.h
@@ -72,8 +72,6 @@ void dhcp_packet_append_ip_headers(DHCPPacket *packet, be32_t source_addr,
 
 int dhcp_packet_verify_headers(DHCPPacket *packet, size_t len, bool checksum, uint16_t port);
 
-void dhcp_client_set_test_mode(sd_dhcp_client *client, bool test_mode);
-
 /* If we are invoking callbacks of a dhcp-client, ensure unreffing the
  * client from the callback doesn't destroy the object we are working
  * on */
diff --git a/src/libsystemd-network/dhcp6-internal.h b/src/libsystemd-network/dhcp6-internal.h
index 97bc82d5210..e5b3b1302c1 100644
--- a/src/libsystemd-network/dhcp6-internal.h
+++ b/src/libsystemd-network/dhcp6-internal.h
@@ -83,9 +83,6 @@ struct sd_dhcp6_client {
         sd_dhcp6_client_callback_t state_callback;
         void *state_userdata;
         bool send_release;
-
-        /* Ignore machine-ID when generating DUID. See dhcp_identifier_set_duid_en(). */
-        bool test_mode;
 };
 
 int dhcp6_network_bind_udp_socket(int ifindex, struct in6_addr *address);
@@ -93,7 +90,6 @@ int dhcp6_network_send_udp_socket(int s, struct in6_addr *address,
                                   const void *packet, size_t len);
 
 int dhcp6_client_send_message(sd_dhcp6_client *client);
-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, ...)         \
diff --git a/src/libsystemd-network/fuzz-dhcp-client.c b/src/libsystemd-network/fuzz-dhcp-client.c
index 9b9e741e534..bdd8a483a15 100644
--- a/src/libsystemd-network/fuzz-dhcp-client.c
+++ b/src/libsystemd-network/fuzz-dhcp-client.c
@@ -54,6 +54,8 @@ int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
         _cleanup_(sd_event_unrefp) sd_event *e = NULL;
         int res, r;
 
+        assert_se(setenv("SYSTEMD_NETWORK_TEST_MODE", "1", 1) >= 0);
+
         if (!getenv("SYSTEMD_LOG_LEVEL"))
                 log_set_max_level(LOG_CRIT);
 
@@ -68,7 +70,6 @@ int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
 
         assert_se(sd_dhcp_client_set_ifindex(client, 42) >= 0);
         assert_se(sd_dhcp_client_set_mac(client, mac_addr, bcast_addr, ETH_ALEN, ARPHRD_ETHER) >= 0);
-        dhcp_client_set_test_mode(client, true);
 
         res = sd_dhcp_client_start(client);
         assert_se(IN_SET(res, 0, -EINPROGRESS));
diff --git a/src/libsystemd-network/fuzz-dhcp6-client.c b/src/libsystemd-network/fuzz-dhcp6-client.c
index 356a9f48fd1..02f556709c0 100644
--- a/src/libsystemd-network/fuzz-dhcp6-client.c
+++ b/src/libsystemd-network/fuzz-dhcp6-client.c
@@ -73,6 +73,8 @@ int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
         struct in6_addr hint = { { { 0x3f, 0xfe, 0x05, 0x01, 0xff, 0xff, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 } } };
         static const char *v1_data = "hogehoge", *v2_data = "foobar";
 
+        assert_se(setenv("SYSTEMD_NETWORK_TEST_MODE", "1", 1) >= 0);
+
         if (outside_size_range(size, 0, 65536))
                 return 0;
 
@@ -81,7 +83,6 @@ int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
         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);
 
         /* Used when sending message. */
         assert_se(sd_dhcp6_client_set_fqdn(client, "example.com") == 1);
diff --git a/src/libsystemd-network/network-common.c b/src/libsystemd-network/network-common.c
index be77d7e0a6e..b23cb8c3533 100644
--- a/src/libsystemd-network/network-common.c
+++ b/src/libsystemd-network/network-common.c
@@ -1,5 +1,6 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
+#include "env-util.h"
 #include "format-util.h"
 #include "network-common.h"
 #include "unaligned.h"
@@ -93,3 +94,21 @@ usec_t time_span_to_stamp(usec_t span, usec_t base) {
 
         return usec_add(base, span);
 }
+
+bool network_test_mode_enabled(void) {
+        static int test_mode = -1;
+        int r;
+
+        if (test_mode < 0) {
+                r = getenv_bool("SYSTEMD_NETWORK_TEST_MODE");
+                if (r < 0) {
+                        if (r != -ENXIO)
+                                log_debug_errno(r, "Failed to parse $SYSTEMD_NETWORK_TEST_MODE environment variable, ignoring: %m");
+
+                        test_mode = false;
+                } else
+                        test_mode = r;
+        }
+
+        return test_mode;
+}
diff --git a/src/libsystemd-network/network-common.h b/src/libsystemd-network/network-common.h
index cf3d1e01304..f71da63b786 100644
--- a/src/libsystemd-network/network-common.h
+++ b/src/libsystemd-network/network-common.h
@@ -39,3 +39,5 @@ be32_t usec_to_be32_sec(usec_t t);
 be32_t usec_to_be32_msec(usec_t t);
 be16_t usec_to_be16_sec(usec_t t);
 usec_t time_span_to_stamp(usec_t span, usec_t base);
+
+bool network_test_mode_enabled(void);
diff --git a/src/libsystemd-network/sd-dhcp-client.c b/src/libsystemd-network/sd-dhcp-client.c
index 79f308f6528..facb2b2424a 100644
--- a/src/libsystemd-network/sd-dhcp-client.c
+++ b/src/libsystemd-network/sd-dhcp-client.c
@@ -125,9 +125,6 @@ struct sd_dhcp_client {
         int ip_service_type;
         int socket_priority;
         bool socket_priority_set;
-
-        /* Ignore machine-ID when generating DUID. See dhcp_identifier_set_duid_en(). */
-        bool test_mode;
 };
 
 static const uint8_t default_req_opts[] = {
@@ -507,7 +504,7 @@ int sd_dhcp_client_set_iaid_duid_en(
         if (r < 0)
                 return r;
 
-        r = dhcp_identifier_set_duid_en(client->test_mode, &client->client_id.ns.duid, &len);
+        r = dhcp_identifier_set_duid_en(&client->client_id.ns.duid, &len);
         if (r < 0)
                 return log_dhcp_client_errno(client, r, "Failed to set DUID-EN: %m");
 
@@ -568,12 +565,6 @@ int sd_dhcp_client_set_iaid_duid_raw(
         return 0;
 }
 
-void dhcp_client_set_test_mode(sd_dhcp_client *client, bool test_mode) {
-        assert(client);
-
-        client->test_mode = test_mode;
-}
-
 int sd_dhcp_client_set_hostname(
                 sd_dhcp_client *client,
                 const char *hostname) {
diff --git a/src/libsystemd-network/sd-dhcp6-client.c b/src/libsystemd-network/sd-dhcp6-client.c
index 4c500fc4a92..d2402e676a7 100644
--- a/src/libsystemd-network/sd-dhcp6-client.c
+++ b/src/libsystemd-network/sd-dhcp6-client.c
@@ -194,7 +194,7 @@ static int client_ensure_duid(sd_dhcp6_client *client) {
         if (client->duid_len != 0)
                 return 0;
 
-        return dhcp_identifier_set_duid_en(client->test_mode, &client->duid, &client->duid_len);
+        return dhcp_identifier_set_duid_en(&client->duid, &client->duid_len);
 }
 
 /**
@@ -234,7 +234,7 @@ int sd_dhcp6_client_set_duid_en(sd_dhcp6_client *client) {
         assert_return(client, -EINVAL);
         assert_return(!sd_dhcp6_client_is_running(client), -EBUSY);
 
-        r = dhcp_identifier_set_duid_en(client->test_mode, &client->duid, &client->duid_len);
+        r = dhcp_identifier_set_duid_en(&client->duid, &client->duid_len);
         if (r < 0)
                 return log_dhcp6_client_errno(client, r, "Failed to set DUID-EN: %m");
 
@@ -348,12 +348,6 @@ int sd_dhcp6_client_get_iaid(sd_dhcp6_client *client, uint32_t *iaid) {
         return 0;
 }
 
-void dhcp6_client_set_test_mode(sd_dhcp6_client *client, bool test_mode) {
-        assert(client);
-
-        client->test_mode = test_mode;
-}
-
 int sd_dhcp6_client_set_fqdn(
                 sd_dhcp6_client *client,
                 const char *fqdn) {
@@ -504,7 +498,7 @@ int sd_dhcp6_client_set_address_request(sd_dhcp6_client *client, int request) {
 
 int dhcp6_client_set_transaction_id(sd_dhcp6_client *client, uint32_t transaction_id) {
         assert(client);
-        assert(client->test_mode);
+        assert_se(network_test_mode_enabled());
 
         /* This is for tests or fuzzers. */
 
diff --git a/src/libsystemd-network/test-dhcp-client.c b/src/libsystemd-network/test-dhcp-client.c
index f3f558a3585..912d4493f54 100644
--- a/src/libsystemd-network/test-dhcp-client.c
+++ b/src/libsystemd-network/test-dhcp-client.c
@@ -168,7 +168,7 @@ static int check_options(uint8_t code, uint8_t len, const void *option, void *us
                 struct duid duid;
                 size_t duid_len;
 
-                assert_se(dhcp_identifier_set_duid_en(/* test_mode = */ true, &duid, &duid_len) >= 0);
+                assert_se(dhcp_identifier_set_duid_en(&duid, &duid_len) >= 0);
                 assert_se(dhcp_identifier_set_iaid(NULL, &hw_addr, /* legacy = */ true, &iaid) >= 0);
 
                 assert_se(len == sizeof(uint8_t) + sizeof(uint32_t) + duid_len);
@@ -291,7 +291,6 @@ static void test_discover_message(sd_event *e) {
 
         assert_se(sd_dhcp_client_set_ifindex(client, 42) >= 0);
         assert_se(sd_dhcp_client_set_mac(client, hw_addr.bytes, bcast_addr.bytes, hw_addr.length, ARPHRD_ETHER) >= 0);
-        dhcp_client_set_test_mode(client, true);
 
         assert_se(sd_dhcp_client_set_request_option(client, 248) >= 0);
 
@@ -509,7 +508,6 @@ static void test_addr_acq(sd_event *e) {
 
         assert_se(sd_dhcp_client_set_ifindex(client, 42) >= 0);
         assert_se(sd_dhcp_client_set_mac(client, hw_addr.bytes, bcast_addr.bytes, hw_addr.length, ARPHRD_ETHER) >= 0);
-        dhcp_client_set_test_mode(client, true);
 
         assert_se(sd_dhcp_client_set_callback(client, test_addr_acq_acquired, e) >= 0);
 
@@ -537,6 +535,8 @@ static void test_addr_acq(sd_event *e) {
 int main(int argc, char *argv[]) {
         _cleanup_(sd_event_unrefp) sd_event *e;
 
+        assert_se(setenv("SYSTEMD_NETWORK_TEST_MODE", "1", 1) >= 0);
+
         test_setup_logging(LOG_DEBUG);
 
         assert_se(sd_event_new(&e) >= 0);
diff --git a/src/libsystemd-network/test-dhcp6-client.c b/src/libsystemd-network/test-dhcp6-client.c
index 7c253b5e5f7..bf9c3f409e0 100644
--- a/src/libsystemd-network/test-dhcp6-client.c
+++ b/src/libsystemd-network/test-dhcp6-client.c
@@ -1073,7 +1073,6 @@ TEST(dhcp6_client) {
         assert_se(sd_dhcp6_client_set_fqdn(client, "host.lab.intra") >= 0);
         assert_se(sd_dhcp6_client_set_iaid(client, unaligned_read_be32((uint8_t[]) { IA_ID_BYTES })) >= 0);
         assert_se(sd_dhcp6_client_set_send_release(client, true) >= 0);
-        dhcp6_client_set_test_mode(client, true);
 
         assert_se(sd_dhcp6_client_set_request_option(client, SD_DHCP6_OPTION_DNS_SERVER) >= 0);
         assert_se(sd_dhcp6_client_set_request_option(client, SD_DHCP6_OPTION_DOMAIN) >= 0);
@@ -1097,4 +1096,9 @@ TEST(dhcp6_client) {
         test_fd[1] = safe_close(test_fd[1]);
 }
 
-DEFINE_TEST_MAIN(LOG_DEBUG);
+static int intro(void) {
+        assert_se(setenv("SYSTEMD_NETWORK_TEST_MODE", "1", 1) >= 0);
+        return 0;
+}
+
+DEFINE_TEST_MAIN_WITH_INTRO(LOG_DEBUG, intro);

From 042c91459aa234c9ce3b3ece0fdad8ba568018f2 Mon Sep 17 00:00:00 2001
From: Yu Watanabe <watanabe.yu+github@gmail.com>
Date: Fri, 6 Oct 2023 13:26:16 +0900
Subject: [PATCH 2/2] fuzz: suppress log messages

---
 src/libsystemd-network/fuzz-dhcp6-client.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/libsystemd-network/fuzz-dhcp6-client.c b/src/libsystemd-network/fuzz-dhcp6-client.c
index 02f556709c0..204c0e15d23 100644
--- a/src/libsystemd-network/fuzz-dhcp6-client.c
+++ b/src/libsystemd-network/fuzz-dhcp6-client.c
@@ -75,6 +75,9 @@ int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
 
         assert_se(setenv("SYSTEMD_NETWORK_TEST_MODE", "1", 1) >= 0);
 
+        if (!getenv("SYSTEMD_LOG_LEVEL"))
+                log_set_max_level(LOG_CRIT);
+
         if (outside_size_range(size, 0, 65536))
                 return 0;