Modify proto/nc_redis.c to reject EVAL/EVALSHA with 0 keys.

src/proto/nc_redis.c

@@ -1127,6 +1127,10 @@ redis_parse_req(struct msg *r)
             break;
 
         case SW_ARG2:
+            if (r->token == NULL) {
+                r->token = p;
+            }
+
             m = p + r->rlen;
             if (m >= b->last) {
                 r->rlen -= (uint32_t)(b->last - p);
@@ -1141,6 +1145,27 @@ redis_parse_req(struct msg *r)
 
             p = m; /* move forward by rlen bytes */
             r->rlen = 0;
+
+            if (redis_argeval(r)) {
+                // For EVAL/EVALSHA, we need to find the integer value of this
+                // argument. It tells us the number of keys in the script, and
+                // we need to error out if number of keys is 0.
+                // At this point, both p and m point to the end of the argument
+                // and r->token points to the start.
+                if (p - r->token <= 1)
+                    goto error;
+                uint32_t nkeys = 0;
+                for (uint8_t *chp = r->token; chp < p; chp++) {
+                    if (isdigit(*chp))
+                        nkeys = nkeys * 10 + (uint32_t)(*chp - '0');
+                    else
+                        goto error;
+                }
+                if (nkeys == 0)
+                    goto error;
+            }
+
+            r->token = NULL;
             state = SW_ARG2_LF;
 
             break;