1 files changed, 115 insertions, 0 deletions
diff --git a/meta-oe/recipes-support/c-ares/c-ares/ares_expand_name-fix-formatting-and-handling-of-root.patch b/meta-oe/recipes-support/c-ares/c-ares/ares_expand_name-fix-formatting-and-handling-of-root.patch
new file mode 100644
index 0000000000..d1cb54aefb
--- /dev/null
+++ b/meta-oe/recipes-support/c-ares/c-ares/ares_expand_name-fix-formatting-and-handling-of-root.patch
@@ -0,0 +1,115 @@
+From: bradh352 <brad@brad-house.com>
+Date: Fri, 11 Jun 2021 12:39:24 -0400
+Subject: [2/2] ares_expand_name(): fix formatting and handling of root name
+ response
+Origin: https://github.com/c-ares/c-ares/commit/44c009b8e62ea1929de68e3f438181bea469ec14
+Bug-Debian-Security: https://security-tracker.debian.org/tracker/CVE-2021-3672
+
+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
+CVE: CVE-2021-3672
+Upstream-Status: Backport [http://snapshot.debian.org/archive/debian-security/20210810T064453Z/pool/updates/main/c/c-ares/c-ares_1.17.1-1%2Bdeb11u1.debian.tar.xz]
+Signed-off-by: Neetika Singh <Neetika.Singh@kpit.com>
+---
+ 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 f1c874a97cfc..eb9268c1ff0a 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
+-- 
+2.32.0
+