libuv: fix CVE-2021-22918

idna: fix OOB read in punycode decoder

libuv was vulnerable to out-of-bounds reads in the uv__idna_toascii()
function which is used to convert strings to ASCII. This is called by
the DNS resolution function and can lead to information disclosures or
crashes.

b7466e31e4
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=990561
https://nodejs.org/en/blog/vulnerability/july-2021-security-releases/

Signed-off-by: Hirokazu MORIKAWA <morikw2@gmail.com>

libs/libuv/patches/CVE-2021-22918.patch

@@ -0,0 +1,166 @@
+From b7466e31e4bee160d82a68fca11b1f61d46debae Mon Sep 17 00:00:00 2001
+From: Ben Noordhuis <info@bnoordhuis.nl>
+Date: Fri, 21 May 2021 11:23:36 +0200
+Subject: [PATCH] idna: fix OOB read in punycode decoder
+
+libuv was vulnerable to out-of-bounds reads in the uv__idna_toascii()
+function which is used to convert strings to ASCII. This is called by
+the DNS resolution function and can lead to information disclosures or
+crashes.
+
+Reported by Eric Sesterhenn in collaboration with Cure53 and ExpressVPN.
+
+Reported-By: Eric Sesterhenn <eric.sesterhenn@x41-dsec.de>
+Fixes: https://github.com/libuv/libuv/issues/3147
+PR-URL: https://github.com/libuv/libuv-private/pull/1
+Refs: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-22918
+Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
+Reviewed-By: Richard Lau <riclau@uk.ibm.com>
+---
+ src/idna.c       | 49 +++++++++++++++++++++++++++++++++++-------------
+ test/test-idna.c | 19 +++++++++++++++++++
+ test/test-list.h |  2 ++
+ 3 files changed, 57 insertions(+), 13 deletions(-)
+
+--- a/src/idna.c
++++ b/src/idna.c
+@@ -19,6 +19,7 @@
+ 
+ #include "uv.h"
+ #include "idna.h"
++#include <assert.h>
+ #include <string.h>
+ 
+ static unsigned uv__utf8_decode1_slow(const char** p,
+@@ -32,7 +33,7 @@ static unsigned uv__utf8_decode1_slow(co
+   if (a > 0xF7)
+     return -1;
+ 
+-  switch (*p - pe) {
++  switch (pe - *p) {
+   default:
+     if (a > 0xEF) {
+       min = 0x10000;
+@@ -62,6 +63,8 @@ static unsigned uv__utf8_decode1_slow(co
+       a = 0;
+       break;
+     }
++    /* Fall through. */
++  case 0:
+     return -1;  /* Invalid continuation byte. */
+   }
+ 
+@@ -88,6 +91,8 @@ static unsigned uv__utf8_decode1_slow(co
+ unsigned uv__utf8_decode1(const char** p, const char* pe) {
+   unsigned a;
+ 
++  assert(*p < pe);
++
+   a = (unsigned char) *(*p)++;
+ 
+   if (a < 128)
+@@ -96,9 +101,6 @@ unsigned uv__utf8_decode1(const char** p
+   return uv__utf8_decode1_slow(p, pe, a);
+ }
+ 
+-#define foreach_codepoint(c, p, pe) \
+-  for (; (void) (*p <= pe && (c = uv__utf8_decode1(p, pe))), *p <= pe;)
+-
+ static int uv__idna_toascii_label(const char* s, const char* se,
+                                   char** d, char* de) {
+   static const char alphabet[] = "abcdefghijklmnopqrstuvwxyz0123456789";
+@@ -121,15 +123,22 @@ static int uv__idna_toascii_label(const
+   ss = s;
+   todo = 0;
+ 
+-  foreach_codepoint(c, &s, se) {
++  /* Note: after this loop we've visited all UTF-8 characters and know
++   * they're legal so we no longer need to check for decode errors.
++   */
++  while (s < se) {
++    c = uv__utf8_decode1(&s, se);
++
++    if (c == -1u)
++      return UV_EINVAL;
++
+     if (c < 128)
+       h++;
+-    else if (c == (unsigned) -1)
+-      return UV_EINVAL;
+     else
+       todo++;
+   }
+ 
++  /* Only write "xn--" when there are non-ASCII characters. */
+   if (todo > 0) {
+     if (*d < de) *(*d)++ = 'x';
+     if (*d < de) *(*d)++ = 'n';
+@@ -137,9 +146,13 @@ static int uv__idna_toascii_label(const
+     if (*d < de) *(*d)++ = '-';
+   }
+ 
++  /* Write ASCII characters. */
+   x = 0;
+   s = ss;
+-  foreach_codepoint(c, &s, se) {
++  while (s < se) {
++    c = uv__utf8_decode1(&s, se);
++    assert(c != -1u);
++
+     if (c > 127)
+       continue;
+ 
+@@ -166,10 +179,15 @@ static int uv__idna_toascii_label(const
+   while (todo > 0) {
+     m = -1;
+     s = ss;
+-    foreach_codepoint(c, &s, se)
++
++    while (s < se) {
++      c = uv__utf8_decode1(&s, se);
++      assert(c != -1u);
++
+       if (c >= n)
+         if (c < m)
+           m = c;
++    }
+ 
+     x = m - n;
+     y = h + 1;
+@@ -181,7 +199,10 @@ static int uv__idna_toascii_label(const
+     n = m;
+ 
+     s = ss;
+-    foreach_codepoint(c, &s, se) {
++    while (s < se) {
++      c = uv__utf8_decode1(&s, se);
++      assert(c != -1u);
++
+       if (c < n)
+         if (++delta == 0)
+           return UV_E2BIG;  /* Overflow. */
+@@ -245,8 +266,6 @@ static int uv__idna_toascii_label(const
+   return 0;
+ }
+ 
+-#undef foreach_codepoint
+-
+ long uv__idna_toascii(const char* s, const char* se, char* d, char* de) {
+   const char* si;
+   const char* st;
+@@ -256,10 +275,14 @@ long uv__idna_toascii(const char* s, con
+ 
+   ds = d;
+ 
+-  for (si = s; si < se; /* empty */) {
++  si = s;
++  while (si < se) {
+     st = si;
+     c = uv__utf8_decode1(&si, se);
+ 
++    if (c == -1u)
++      return UV_EINVAL;
++
+     if (c != '.')
+       if (c != 0x3002)  /* 。 */
+         if (c != 0xFF0E)  /* ． */