check for workspace overflow after calling WS_Reserve()

src/vmod_re2.c

@@ -248,6 +248,11 @@ sub(VRT_CTX, vre2 * restrict vre2, const int all, VCL_STRING text,
 
 	ret = WS_Snapshot(ctx->ws);
 	bytes = WS_Reserve(ctx->ws, 0);
+	if (bytes == 0) {
+		VERR(ctx, ERR_PREFIX "workspace overflow", text, rewrite,
+		     fallback);
+		return fallback;
+	}
 	if ((err = vre2_replace(vre2, all, text, rewrite, ret, bytes, &match,
 				&len))
 	    != NULL) {
@@ -278,6 +283,11 @@ extract(VRT_CTX, vre2 * restrict vre2, VCL_STRING text, VCL_STRING rewrite,
 
 	ret = WS_Snapshot(ctx->ws);
 	bytes = WS_Reserve(ctx->ws, 0);
+	if (bytes == 0) {
+		VERR(ctx, ERR_PREFIX "workspace overflow", text, rewrite,
+		     fallback);
+		return fallback;
+	}
 	if ((err = vre2_extract(vre2, text, rewrite, ret, bytes, &match, &len))
 	    != NULL) {
 		VERR(ctx, ERR_PREFIX "%s", text, rewrite, fallback, err);