Copy the match subject into workspace if it's not already in workspace,

so that backref/namedref are guaranteed to return strings in workspace.

src/vmod_pcre2.c

@@ -557,18 +557,32 @@ match(VRT_CTX, pcre2_code *code, VCL_STRING subject, VCL_INT len,
       uint32_t options, pcre2_match_data *mdata, pcre2_match_context *mctx,
       const char * restrict const context, const char * restrict const caller)
 {
+	PCRE2_SPTR safe_subject;
 	int ret;
 	uintptr_t snap;
 	char *msg;
 
-	if (subject == NULL)
-		subject = "";
-	if (len == 0)
-		len = PCRE2_ZERO_TERMINATED;
+	if (subject == NULL) {
+		safe_subject = (PCRE2_SPTR)"";
+		len = 0;
+	}
+	else if (len == 0)
+		len = strlen(subject);
+	if (subject != NULL) {
+		if (WS_Inside(ctx->ws, subject, subject + len))
+			safe_subject = (PCRE2_SPTR)subject;
+		else if ((safe_subject = WS_Copy(ctx->ws,
+						 (const void *) subject, len))
+			 == NULL) {
+			VERRNOMEM(ctx, "in %s%s: copying subject to workspace",
+				  context, caller);
+			return 0;
+		}
+	}
 
 	/* XXX param for start_offset */
-	ret = pcre2_match(code, (PCRE2_SPTR)subject, (PCRE2_SIZE)len, 0,
-			  options, mdata, mctx);
+	ret = pcre2_match(code, safe_subject, (PCRE2_SIZE)len, 0, options,
+			  mdata, mctx);
 	if (ret == PCRE2_ERROR_NOMATCH)
 		return 0;
 	assert(ret != PCRE2_ERROR_PARTIAL); /* XXX */