in_kafka: add NULL check for SASL mechanism allocation

Add NULL check after flb_sds_create() when allocating SASL mechanism string during AWS MSK IAM setup to prevent crashes on allocation failure.

Signed-off-by: Arbin <[email protected]>

Author: kalavt

plugins/in_kafka/in_kafka.c

@@ -284,6 +284,11 @@ static int in_kafka_init(struct flb_input_instance *ins,
             flb_input_set_property(ins, "rdkafka.sasl.mechanism", "OAUTHBEARER");
             flb_sds_destroy(ctx->sasl_mechanism);
             ctx->sasl_mechanism = flb_sds_create("OAUTHBEARER");
+            if (!ctx->sasl_mechanism) {
+                flb_plg_error(ins, "failed to allocate SASL mechanism string");
+                flb_free(ctx);
+                return -1;
+            }
 
             /* Ensure security protocol is set */
             conf = flb_input_get_property("rdkafka.security.protocol", ins);