diff --git a/shared/systemd/src/basic/siphash24.h b/shared/systemd/src/basic/siphash24.h
index 37a9c6c351..e46f3cc5be 100644
--- a/shared/systemd/src/basic/siphash24.h
+++ b/shared/systemd/src/basic/siphash24.h
@@ -5,9 +5,9 @@
 #include <inttypes.h>
 #include <stddef.h>
 #include <stdint.h>
-#include <string.h>
 #include <sys/types.h>
 
+#include "string-util.h"
 #include "time-util.h"
 
 #if 0 /* NM_IGNORED */
@@ -63,11 +63,15 @@ static inline void siphash24_compress_usec_t(usec_t in, struct siphash *state) {
         siphash24_compress(&in, sizeof in, state);
 }
 
-static inline void siphash24_compress_string(const char *in, struct siphash *state) {
-        if (!in)
+static inline void siphash24_compress_safe(const void *in, size_t inlen, struct siphash *state) {
+        if (inlen == 0)
                 return;
 
-        siphash24_compress(in, strlen(in), state);
+        siphash24_compress(in, inlen, state);
+}
+
+static inline void siphash24_compress_string(const char *in, struct siphash *state) {
+        siphash24_compress_safe(in, strlen_ptr(in), state);
 }
 
 uint64_t siphash24_finalize(struct siphash *state);
diff --git a/shared/systemd/src/shared/dns-domain.c b/shared/systemd/src/shared/dns-domain.c
index dff7e83a19..95e4a93afd 100644
--- a/shared/systemd/src/shared/dns-domain.c
+++ b/shared/systemd/src/shared/dns-domain.c
@@ -1289,7 +1289,7 @@ int dns_name_apply_idna(const char *name, char **ret) {
         int r;
 
         r = dlopen_idn();
-        if (r == EOPNOTSUPP) {
+        if (r == -EOPNOTSUPP) {
                 *ret = NULL;
                 return 0;
         }
diff --git a/src/systemd/src/libsystemd-network/sd-dhcp-client.c b/src/systemd/src/libsystemd-network/sd-dhcp-client.c
index 95703aafc2..27a3476fcf 100644
--- a/src/systemd/src/libsystemd-network/sd-dhcp-client.c
+++ b/src/systemd/src/libsystemd-network/sd-dhcp-client.c
@@ -1278,9 +1278,11 @@ static int client_timeout_resend(
                 break;
 
         case DHCP_STATE_STOPPED:
-        default:
                 r = -EINVAL;
                 goto error;
+
+        default:
+                assert_not_reached("Unhandled choice");
         }
 
         r = event_reset_time(client->event, &client->timeout_resend,