From 8976ad7ecbd6a0c70749e3bef9c508d0bfde02d2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Luis=20C=C3=A1ceres?= <lacc97@protonmail.ch>
Date: Wed, 30 Aug 2023 22:39:15 +0000
Subject: [PATCH] std.net: Fix IPv6 address parsing for single digit

This fixes the case where IPv6 address parsing incorrectly succeeded on
input such as `1`, which now returns error.Incomplete.
---
 lib/std/net.zig      | 3 +++
 lib/std/net/test.zig | 3 +++
 2 files changed, 6 insertions(+)

diff --git a/lib/std/net.zig b/lib/std/net.zig
index b03c7e09dc..b6f0f20f2c 100644
--- a/lib/std/net.zig
+++ b/lib/std/net.zig
@@ -406,6 +406,9 @@ pub const Ip6Address = extern struct {
         if (!saw_any_digits and !abbrv) {
             return error.Incomplete;
         }
+        if (!abbrv and index < 14) {
+            return error.Incomplete;
+        }
 
         if (index == 14) {
             ip_slice[14] = @as(u8, @truncate(x >> 8));
diff --git a/lib/std/net/test.zig b/lib/std/net/test.zig
index 817d6c2593..fd92c64f35 100644
--- a/lib/std/net/test.zig
+++ b/lib/std/net/test.zig
@@ -13,6 +13,7 @@ test "parse and render IPv6 addresses" {
         "FF01::Fb",
         "::1",
         "::",
+        "1::",
         "2001:db8::",
         "::1234:5678",
         "2001:db8::1234:5678",
@@ -24,6 +25,7 @@ test "parse and render IPv6 addresses" {
         "ff01::fb",
         "::1",
         "::",
+        "1::",
         "2001:db8::",
         "::1234:5678",
         "2001:db8::1234:5678",
@@ -48,6 +50,7 @@ test "parse and render IPv6 addresses" {
     try testing.expectError(error.InvalidEnd, net.Address.parseIp6("FF01:0:0:0:0:0:0:FB:", 0));
     try testing.expectError(error.Incomplete, net.Address.parseIp6("FF01:", 0));
     try testing.expectError(error.InvalidIpv4Mapping, net.Address.parseIp6("::123.123.123.123", 0));
+    try testing.expectError(error.Incomplete, net.Address.parseIp6("1", 0));
     // TODO Make this test pass on other operating systems.
     if (builtin.os.tag == .linux or comptime builtin.os.tag.isDarwin()) {
         try testing.expectError(error.Incomplete, net.Address.resolveIp6("ff01::fb%", 0));