basic: util - fix errorhandling in unhexmem()

We were ignoring failures from unhexchar, which meant that invalid
hex characters were being turned into garbage rather than the string
rejected.

Fix this by making unhexmem return an error code, also change the API
slightly, to return the size of the returned memory, reflecting the
fact that the memory is a binary blob,and not a string.

For convenience, still append a trailing NULL byte to the returned
memory (not included in the returned size), allowing callers to
treat it as a string without doing a second copy.

1 files changed, 4 insertions, 5 deletions

diff --git a/src/libsystemd-network/sd-dhcp-lease.c b/src/libsystemd-network/sd-dhcp-lease.c
index d8bc76edda..7548e50b7d 100644
--- a/src/libsystemd-network/sd-dhcp-lease.c
+++ b/src/libsystemd-network/sd-dhcp-lease.c
@@ -811,13 +811,12 @@ int sd_dhcp_lease_load(sd_dhcp_lease **ret, const char *lease_file) {
         }
 
         if (client_id_hex) {
-                if (strlen (client_id_hex) % 2)
+                if (strlen(client_id_hex) % 2)
                         return -EINVAL;
 
-                lease->client_id = unhexmem (client_id_hex, strlen (client_id_hex));
-                if (!lease->client_id)
-                        return -ENOMEM;
-                lease->client_id_len = strlen (client_id_hex) / 2;
+                r = unhexmem(client_id_hex, strlen(client_id_hex), (void**) &lease->client_id, &lease->client_id_len);
+                if (r < 0)
+                        return r;
         }
 
         *ret = lease;