fix CVE-2021-3672

(cherry picked from commit 61c5da0b8e4e62f25ad592f56d559313c245b593)

backport-001-CVE-2021-3672.patch

@@ -0,0 +1,83 @@
+From 362f91d807d293791008cdb7616d40f7784ece83 Mon Sep 17 00:00:00 2001
+From: bradh352 <brad@brad-house.com>
+Date: Fri, 11 Jun 2021 11:27:45 -0400
+Subject: [PATCH] ares_expand_name() should escape more characters
+
+RFC1035 5.1 specifies some reserved characters and escaping sequences
+that are allowed to be specified.  Expand the list of reserved characters
+and also escape non-printable characters using the \DDD format as
+specified in the RFC.
+
+Bug Reported By: philipp.jeitner@sit.fraunhofer.de
+Fix By: Brad House (@bradh352)
+---
+ ares_expand_name.c | 41 +++++++++++++++++++++++++++++++++++---
+ 1 file changed, 38 insertions(+), 3 deletions(-)
+
+diff --git a/ares_expand_name.c b/ares_expand_name.c
+index 407200ef..f1c874a9 100644
+--- a/ares_expand_name.c
++++ b/ares_expand_name.c
+@@ -32,6 +32,26 @@
+ static int name_length(const unsigned char *encoded, const unsigned char *abuf,
+                        int alen);
+ 
++/* Reserved characters for names that need to be escaped */
++static int is_reservedch(int ch)
++{
++  switch (ch) {
++    case '"':
++    case '.':
++    case ';':
++    case '\\':
++    case '(':
++    case ')':
++    case '@':
++    case '$':
++      return 1;
++    default:
++      break;
++  }
++
++  return 0;
++}
++
+ /* Expand an RFC1035-encoded domain name given by encoded.  The
+  * containing message is given by abuf and alen.  The result given by
+  * *s, which is set to a NUL-terminated allocated buffer.  *enclen is
+@@ -111,9 +131,18 @@ int ares_expand_name(const unsigned char *encoded, const unsigned char *abuf,
+           p++;
+           while (len--)
+             {
+-              if (*p == '.' || *p == '\\')
++              if (!isprint(*p)) {
++                /* Output as \DDD for consistency with RFC1035 5.1 */
++                *q++ = '\\';
++                *q++ = '0' + *p / 100;
++                *q++ = '0' + (*p % 100) / 10;
++                *q++ = '0' + (*p % 10);
++              } else if (is_reservedch(*p)) {
+                 *q++ = '\\';
+-              *q++ = *p;
++                *q++ = *p;
++              } else {
++                *q++ = *p;
++              }
+               p++;
+             }
+           *q++ = '.';
+@@ -171,7 +200,13 @@ static int name_length(const unsigned char *encoded, const unsigned char *abuf,
+           encoded++;
+           while (offset--)
+             {
+-              n += (*encoded == '.' || *encoded == '\\') ? 2 : 1;
++              if (!isprint(*encoded)) {
++                n += 4;
++              } else if (is_reservedch(*encoded)) {
++                n += 2;
++              } else {
++                n += 1;
++              }
+               encoded++;
+             }
+           n++;

backport-002-CVE-2021-3672.patch

@@ -0,0 +1,108 @@
+From 44c009b8e62ea1929de68e3f438181bea469ec14 Mon Sep 17 00:00:00 2001
+From: bradh352 <brad@brad-house.com>
+Date: Fri, 11 Jun 2021 12:39:24 -0400
+Subject: [PATCH] ares_expand_name(): fix formatting and handling of root name
+ response
+
+Fixes issue introduced in prior commit with formatting and handling
+of parsing a root name response which should not be escaped.
+
+Fix By: Brad House
+---
+ ares_expand_name.c | 62 ++++++++++++++++++++++++--------------
+ 1 file changed, 40 insertions(+), 22 deletions(-)
+
+diff --git a/ares_expand_name.c b/ares_expand_name.c
+index f1c874a9..eb9268c1 100644
+--- a/ares_expand_name.c
++++ b/ares_expand_name.c
+@@ -127,27 +127,37 @@ int ares_expand_name(const unsigned char *encoded, const unsigned char *abuf,
+         }
+       else
+         {
+-          len = *p;
++          int name_len = *p;
++          len = name_len;
+           p++;
++
+           while (len--)
+             {
+-              if (!isprint(*p)) {
+-                /* Output as \DDD for consistency with RFC1035 5.1 */
+-                *q++ = '\\';
+-                *q++ = '0' + *p / 100;
+-                *q++ = '0' + (*p % 100) / 10;
+-                *q++ = '0' + (*p % 10);
+-              } else if (is_reservedch(*p)) {
+-                *q++ = '\\';
+-                *q++ = *p;
+-              } else {
+-                *q++ = *p;
+-              }
++              /* Output as \DDD for consistency with RFC1035 5.1, except
++               * for the special case of a root name response  */
++              if (!isprint(*p) && !(name_len == 1 && *p == 0))
++                {
++
++                  *q++ = '\\';
++                  *q++ = '0' + *p / 100;
++                  *q++ = '0' + (*p % 100) / 10;
++                  *q++ = '0' + (*p % 10);
++                }
++              else if (is_reservedch(*p))
++                {
++                  *q++ = '\\';
++                  *q++ = *p;
++                }
++              else
++                {
++                  *q++ = *p;
++                }
+               p++;
+             }
+           *q++ = '.';
+         }
+-    }
++     }
++
+   if (!indir)
+     *enclen = aresx_uztosl(p + 1U - encoded);
+ 
+@@ -194,21 +204,29 @@ static int name_length(const unsigned char *encoded, const unsigned char *abuf,
+         }
+       else if (top == 0x00)
+         {
+-          offset = *encoded;
++          int name_len = *encoded;
++          offset = name_len;
+           if (encoded + offset + 1 >= abuf + alen)
+             return -1;
+           encoded++;
++
+           while (offset--)
+             {
+-              if (!isprint(*encoded)) {
+-                n += 4;
+-              } else if (is_reservedch(*encoded)) {
+-                n += 2;
+-              } else {
+-                n += 1;
+-              }
++              if (!isprint(*encoded) && !(name_len == 1 && *encoded == 0))
++                {
++                  n += 4;
++                }
++              else if (is_reservedch(*encoded))
++                {
++                  n += 2;
++                }
++              else
++                {
++                  n += 1;
++                }
+               encoded++;
+             }
++
+           n++;
+         }
+       else

c-ares.spec

@@ -1,6 +1,6 @@
 Name:           c-ares
 Version:        1.16.1
-Release:        2
+Release:        3
 Summary:        A C library for asynchronous DNS requests
 
 License:        MIT
@@ -14,6 +14,8 @@ Patch1:         0001-Fix-invalid-read-in-ares_parse_soa_reply.patch
 Patch2:         0002-Fix-sizeof-sizeof-addr.saX-sizeof-addr.saX-in-readad.patch
 Patch3:         0003-Avoid-buffer-overflow-in-RC4-loop-comparison-336.patch
 Patch4:         CVE-2020-8277.patch
+Patch5:         backport-001-CVE-2021-3672.patch
+Patch6:         backport-002-CVE-2021-3672.patch
 %description
 This is c-ares, an asynchronous resolver library. It is intended for applications
 which need to perform DNS queries without blocking, or need to perform multiple
@@ -56,6 +58,9 @@ make %{?_smp_mflags}
 %{_mandir}/man3/*
 
 %changelog
+* Thu Aug 12 2021 gaihuiying <gaihuiying1@huawei.com> - 1.16.1-3
+- fix CVE-2021-3672
+
 * Thu Mar 11 2021 openEuler Buildteam <buildteam@openeuler.org> - 1.16.1-2
 - fix CVE-2020-8277