From 3530bcc30350d4a6ccf35d2f7b33e23292b9de70 Mon Sep 17 00:00:00 2001
From: Ben Noordhuis <info@bnoordhuis.nl>
Date: Thu, 18 Jan 2024 14:52:38 +0100
Subject: [PATCH] fix: reject zero-length idna inputs

Fixes: https://github.com/libuv/libuv/security/advisories/GHSA-f74f-cvh7-c6q6
---
 src/idna.c       | 3 +++
 test/test-idna.c | 1 +
 2 files changed, 4 insertions(+)

diff --git a/src/idna.c b/src/idna.c
index 4638546d020..efc5f283ce2 100644
--- a/src/idna.c
+++ b/src/idna.c
@@ -322,6 +322,9 @@ ssize_t uv__idna_toascii(const char* s, const char* se, char* d, char* de) {
   char* ds;
   int rc;
 
+  if (s == se)
+    return UV_EINVAL;
+
   ds = d;
 
   si = s;
diff --git a/test/test-idna.c b/test/test-idna.c
index 5f8d696a7f0..3c4820f7659 100644
--- a/test/test-idna.c
+++ b/test/test-idna.c
@@ -115,6 +115,7 @@ TEST_IMPL(utf8_decode1_overrun) {
   ASSERT_PTR_EQ(p, b + 1);
 
   b[0] = 0x7F;
+  ASSERT_EQ(UV_EINVAL, uv__idna_toascii(b, b + 0, c, c + 1));
   ASSERT_EQ(UV_EINVAL, uv__idna_toascii(b, b + 1, c, c + 1));
 
   return 0;