c-ares: fix CVE-2023-32067

c-ares is an asynchronous resolver library. c-ares is vulnerable
to denial of service. If a target resolver sends a query, the attacker
forges a malformed UDP packet with a length of 0 and returns them to
the target resolver. The target resolver erroneously interprets the 0
length as a graceful shutdown of the connection. This issue has been
patched in version 1.19.1.

References:
https://nvd.nist.gov/vuln/detail/CVE-2023-32067
https://github.com/c-ares/c-ares/security/advisories/GHSA-9g78-jv2r-p7vc

Signed-off-by: Yogita Urade <yogita.urade@windriver.com>
Signed-off-by: Armin Kuster <akuster808@gmail.com>

2 files changed, 90 insertions, 1 deletions

diff --git a/meta-oe/recipes-support/c-ares/c-ares/CVE-2023-32067.patch b/meta-oe/recipes-support/c-ares/c-ares/CVE-2023-32067.patch
new file mode 100644
index 0000000000..cd13e7d9e5
--- /dev/null
+++ b/meta-oe/recipes-support/c-ares/c-ares/CVE-2023-32067.patch
@@ -0,0 +1,87 @@
+From b9b8413cfdb70a3f99e1573333b23052d57ec1ae Mon Sep 17 00:00:00 2001
+From: Brad House <brad@brad-house.com>
+Date: Mon, 22 May 2023 06:51:49 -0400
+Subject: [PATCH] Merge pull request from GHSA-9g78-jv2r-p7vc
+
+CVE: CVE-2023-32067
+
+Upstream Status: Backport
+[https://github.com/c-ares/c-ares/commit/b9b8413cfdb70a3f99e1573333b23052d57ec1ae]
+
+Signed-off-by: Yogita Urade <yogita.urade@windriver.com>
+---
+ src/lib/ares_process.c | 41 +++++++++++++++++++++++++----------------
+ 1 file changed, 25 insertions(+), 16 deletions(-)
+
+diff --git a/src/lib/ares_process.c b/src/lib/ares_process.c
+index bf0cde4..6cac0a9 100644
+--- a/src/lib/ares_process.c
++++ b/src/lib/ares_process.c
+@@ -470,7 +470,7 @@ static void read_udp_packets(ares_channel channel, fd_set *read_fds,
+ {
+   struct server_state *server;
+   int i;
+-  ares_ssize_t count;
++  ares_ssize_t read_len;
+   unsigned char buf[MAXENDSSZ + 1];
+ #ifdef HAVE_RECVFROM
+   ares_socklen_t fromlen;
+@@ -513,32 +513,41 @@ static void read_udp_packets(ares_channel channel, fd_set *read_fds,
+       /* To reduce event loop overhead, read and process as many
+        * packets as we can. */
+       do {
+-        if (server->udp_socket == ARES_SOCKET_BAD)
+-          count = 0;
+-
+-        else {
+-          if (server->addr.family == AF_INET)
++        if (server->udp_socket == ARES_SOCKET_BAD) {
++          read_len = -1;
++        } else {
++          if (server->addr.family == AF_INET) {
+             fromlen = sizeof(from.sa4);
+-          else
++          } else {
+             fromlen = sizeof(from.sa6);
+-          count = socket_recvfrom(channel, server->udp_socket, (void *)buf,
+-                                  sizeof(buf), 0, &from.sa, &fromlen);
++          }
++          read_len = socket_recvfrom(channel, server->udp_socket, (void *)buf,
++                                     sizeof(buf), 0, &from.sa, &fromlen);
+         }
+
+-        if (count == -1 && try_again(SOCKERRNO))
++        if (read_len == 0) {
++          /* UDP is connectionless, so result code of 0 is a 0-length UDP
++           * packet, and not an indication the connection is closed like on
++           * tcp */
+           continue;
+-        else if (count <= 0)
++        } else if (read_len < 0) {
++          if (try_again(SOCKERRNO))
++            continue;
++
+           handle_error(channel, i, now);
++
+ #ifdef HAVE_RECVFROM
+-        else if (!same_address(&from.sa, &server->addr))
++        } else if (!same_address(&from.sa, &server->addr)) {
+           /* The address the response comes from does not match the address we
+            * sent the request to. Someone may be attempting to perform a cache
+            * poisoning attack. */
+-          break;
++          continue;
+ #endif
+-        else
+-          process_answer(channel, buf, (int)count, i, 0, now);
+-       } while (count > 0);
++
++        } else {
++          process_answer(channel, buf, (int)read_len, i, 0, now);
++        }
++      } while (read_len >= 0);
+     }
+ }
+
+--
+2.40.0
diff --git a/meta-oe/recipes-support/c-ares/c-ares_1.19.0.bb b/meta-oe/recipes-support/c-ares/c-ares_1.19.0.bb
index bb19ff1bd3..997f27a895 100644
--- a/meta-oe/recipes-support/c-ares/c-ares_1.19.0.bb
+++ b/meta-oe/recipes-support/c-ares/c-ares_1.19.0.bb
@@ -5,7 +5,9 @@ SECTION = "libs"
 LICENSE = "MIT"
 LIC_FILES_CHKSUM = "file://LICENSE.md;md5=fb997454c8d62aa6a47f07a8cd48b006"
 
-SRC_URI = "git://github.com/c-ares/c-ares.git;branch=main;protocol=https"
+SRC_URI = "git://github.com/c-ares/c-ares.git;branch=main;protocol=https \
+           file://CVE-2023-32067.patch \
+          "
 SRCREV = "fddf01938d3789e06cc1c3774e4cd0c7d2a89976"
 
 UPSTREAM_CHECK_GITTAGREGEX = "cares-(?P<pver>\d+_(\d_?)+)"