detect-parse: parse sid in pre-scan

During the pre-scan for "requires", also parse the SID if possible. If
the rule fails high level parsing (syntax), the SID will not be
parsed.

But every keyword other than "sid" and "requires" should expect to be
provided with a parsed sid.

src/detect-parse.c

@@ -900,10 +900,11 @@ static int SigParseOptions(DetectEngineCtx *de_ctx, Signature *s, char *optstr,
     }
     optname = optstr;
 
-    if (requires) {
-        if (strcmp(optname, "requires")) {
-            goto finish;
-        }
+    /* Check for options that are only to be processed during the
+     * first "requires" pass. */
+    bool requires_only = strcmp(optname, "requires") == 0 || strcmp(optname, "sid") == 0;
+    if ((requires && !requires_only) || (!requires && requires_only)) {
+        goto finish;
     }
 
     /* Call option parsing */
@@ -2137,10 +2138,7 @@ static int SigValidate(DetectEngineCtx *de_ctx, Signature *s)
             AppLayerHtpNeedFileInspection();
         }
     }
-    if (s->id == 0) {
-        SCLogError("Signature missing required value \"sid\".");
-        SCReturnInt(0);
-    }
+
     SCReturnInt(1);
 }
 
@@ -2181,6 +2179,12 @@ static Signature *SigInitHelper(DetectEngineCtx *de_ctx, const char *sigstr,
         goto error;
     }
 
+    /* Check for a SID before continuuing. */
+    if (sig->id == 0) {
+        SCLogError("Signature missing required value \"sid\".");
+        goto error;
+    }
+
     /* Now completely parse the rule. */
     ret = SigParse(de_ctx, sig, sigstr, dir, &parser, false);
     BUG_ON(ret == -4);