From fe24f3249b41decd6195f8e1c7421237f46a7f35 Mon Sep 17 00:00:00 2001
From: Aram Sargsyan <aram@isc.org>
Date: Tue, 16 Jun 2026 11:08:14 +0000
Subject: [PATCH] Add a maximum length for isc_url_parse() input buffer

The isc_url_parse() function failed to check the input buffer's
length and assumed that it can't be bigger than UINT16_MAX, because
both the 'off' and 'len' fields of the 'isc_url_parser_t' structure
are uint16_t.

Add a check to not accept a buffer longer than UINT16_MAX.

(cherry picked from commit b878f82409468842acf56c496025cee19b66a2bc)
---
 lib/isc/url.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/isc/url.c b/lib/isc/url.c
index 6ba4cb4991..e6a3b830ee 100644
--- a/lib/isc/url.c
+++ b/lib/isc/url.c
@@ -549,8 +549,8 @@ isc_url_parse(const char *buf, size_t buflen, bool is_connect,
 	int found_at = 0;
 	const char *p = NULL;
 
-	if (buflen == 0) {
-		return ISC_R_FAILURE;
+	if (buflen == 0 || buflen > UINT16_MAX) {
+		return ISC_R_RANGE;
 	}
 
 	up->port = up->field_set = 0;