sd-bus: make strict asan shut up

asan doesn't like it if we use strndup() (i.e. a string function) on a
non-NULL terminated buffer (i.e. something that isn't really a string).

Let's hence use memdup_suffix0() instead of strndup(), which is more
appropriate for binary data that is to become a string.

Fixes: #10385
(cherry picked from commit ac0a94f7438b49a0890d9806db1fa211a5bca10a)

Resolves: #1761519

1 files changed, 5 insertions, 2 deletions

diff --git a/src/libsystemd/sd-bus/bus-message.c b/src/libsystemd/sd-bus/bus-message.c
index 53cbd675b7..19cb2b9a97 100644
--- a/src/libsystemd/sd-bus/bus-message.c
+++ b/src/libsystemd/sd-bus/bus-message.c
@@ -5101,6 +5101,7 @@ int bus_message_parse_fields(sd_bus_message *m) {
                                 return -EBADMSG;
 
                         if (*p == 0) {
+                                char *k;
                                 size_t l;
 
                                 /* We found the beginning of the signature
@@ -5114,9 +5115,11 @@ int bus_message_parse_fields(sd_bus_message *m) {
                                     p[1 + l - 1] != SD_BUS_TYPE_STRUCT_END)
                                         return -EBADMSG;
 
-                                if (free_and_strndup(&m->root_container.signature,
-                                                     p + 1 + 1, l - 2) < 0)
+                                k = memdup_suffix0(p + 1 + 1, l - 2);
+                                if (!k)
                                         return -ENOMEM;
+
+                                free_and_replace(m->root_container.signature, k);
                                 break;
                         }