Check for NULL before passing it to vsnprintf

src/config.c

@@ -1144,7 +1144,7 @@ int git_config_parse_int64(int64_t *out, const char *value)
 	}
 
 fail_parse:
-	giterr_set(GITERR_CONFIG, "Failed to parse '%s' as an integer", value);
+	giterr_set(GITERR_CONFIG, "Failed to parse '%s' as an integer", value ? value : "(null)");
 	return -1;
 }
 
@@ -1164,7 +1164,7 @@ int git_config_parse_int32(int32_t *out, const char *value)
 	return 0;
 
 fail_parse:
-	giterr_set(GITERR_CONFIG, "Failed to parse '%s' as a 32-bit integer", value);
+	giterr_set(GITERR_CONFIG, "Failed to parse '%s' as a 32-bit integer", value ? value : "(null)");
 	return -1;
 }
 

src/remote.c

@@ -73,7 +73,7 @@ static int ensure_remote_name_is_valid(const char *name)
 	if (!git_remote_is_valid_name(name)) {
 		giterr_set(
 			GITERR_CONFIG,
-			"'%s' is not a valid remote name.", name);
+			"'%s' is not a valid remote name.", name ? name : "(null)");
 		error = GIT_EINVALIDSPEC;
 	}