openssh: Fix CVE-2023-51385

OS command injection might occur if a user name or host name has shell
metacharacters, and this name is referenced by an expansion token in
certain situations. For example, an untrusted Git repository can have a
submodule with shell metacharacters in a user name or host name.

This patch fixes the above issue

Link: http://archive.ubuntu.com/ubuntu/pool/main/o/openssh/openssh_8.2p1-4ubuntu0.11.debian.tar.xz
Link: https://github.com/openssh/openssh-portable/commit/7ef3787c84b6b524501211b11a26c742f829af1a

(From OE-Core rev: a0561ca36bd3be8f44d11908caaf8c9ce5f69032)

Signed-off-by: Ranjitsinh Rathod <ranjitsinh.rathod@kpit.com>
Signed-off-by: Ranjitsinh Rathod <ranjitsinhrathod1991@gmail.com>
Signed-off-by: Steve Sakoman <steve@sakoman.com>

2 files changed, 96 insertions, 0 deletions

diff --git a/meta/recipes-connectivity/openssh/openssh/CVE-2023-51385.patch b/meta/recipes-connectivity/openssh/openssh/CVE-2023-51385.patch
new file mode 100644
index 0000000000..0ba8c312d0
--- /dev/null
+++ b/meta/recipes-connectivity/openssh/openssh/CVE-2023-51385.patch
@@ -0,0 +1,95 @@
+From 7ef3787c84b6b524501211b11a26c742f829af1a Mon Sep 17 00:00:00 2001
+From: "djm@openbsd.org" <djm@openbsd.org>
+Date: Mon, 18 Dec 2023 14:47:44 +0000
+Subject: [PATCH] upstream: ban user/hostnames with most shell metacharacters
+
+This makes ssh(1) refuse user or host names provided on the
+commandline that contain most shell metacharacters.
+
+Some programs that invoke ssh(1) using untrusted data do not filter
+metacharacters in arguments they supply. This could create
+interactions with user-specified ProxyCommand and other directives
+that allow shell injection attacks to occur.
+
+It's a mistake to invoke ssh(1) with arbitrary untrusted arguments,
+but getting this stuff right can be tricky, so this should prevent
+most obvious ways of creating risky situations. It however is not
+and cannot be perfect: ssh(1) has no practical way of interpreting
+what shell quoting rules are in use and how they interact with the
+user's specified ProxyCommand.
+
+To allow configurations that use strange user or hostnames to
+continue to work, this strictness is applied only to names coming
+from the commandline. Names specified using User or Hostname
+directives in ssh_config(5) are not affected.
+
+feedback/ok millert@ markus@ dtucker@ deraadt@
+
+OpenBSD-Commit-ID: 3b487348b5964f3e77b6b4d3da4c3b439e94b2d9
+
+CVE: CVE-2023-51385
+Upstream-Status: Backport [https://github.com/openssh/openssh-portable/commit/7ef3787c84b6b524501211b11a26c742f829af1a]
+Signed-off-by: Ranjitsinh Rathod <ranjitsinh.rathod@kpit.com>
+Comment: Hunks refreshed to apply cleanly
+
+---
+ ssh.c | 41 ++++++++++++++++++++++++++++++++++++++++-
+ 1 file changed, 40 insertions(+), 1 deletion(-)
+
+diff --git a/ssh.c b/ssh.c
+index 35c48e62d18..48d93ddf2a9 100644
+--- a/ssh.c
++++ b/ssh.c
+@@ -583,6 +583,41 @@ set_addrinfo_port(struct addrinfo *addrs
+        }
+ }
+ 
++static int
++valid_hostname(const char *s)
++{
++       size_t i;
++
++       if (*s == '-')
++               return 0;
++       for (i = 0; s[i] != 0; i++) {
++               if (strchr("'`\"$\\;&<>|(){}", s[i]) != NULL ||
++                   isspace((u_char)s[i]) || iscntrl((u_char)s[i]))
++                       return 0;
++       }
++       return 1;
++}
++
++static int
++valid_ruser(const char *s)
++{
++       size_t i;
++
++       if (*s == '-')
++               return 0;
++       for (i = 0; s[i] != 0; i++) {
++               if (strchr("'`\";&<>|(){}", s[i]) != NULL)
++                       return 0;
++               /* Disallow '-' after whitespace */
++               if (isspace((u_char)s[i]) && s[i + 1] == '-')
++                       return 0;
++               /* Disallow \ in last position */
++               if (s[i] == '\\' && s[i + 1] == '\0')
++                       return 0;
++       }
++       return 1;
++}
++
+ /*
+  * Main program for the ssh client.
+  */
+@@ -1069,6 +1104,10 @@ main(int ac, char **av)
+        if (!host)
+                usage();
+ 
++       if (!valid_hostname(host))
++               fatal("hostname contains invalid characters");
++       if (options.user != NULL && !valid_ruser(options.user))
++               fatal("remote username contains invalid characters");
+        host_arg = xstrdup(host);
+ 
+        /* Initialize the command to execute on remote host. */
diff --git a/meta/recipes-connectivity/openssh/openssh_8.2p1.bb b/meta/recipes-connectivity/openssh/openssh_8.2p1.bb
index eb3089cd8a..9d6cf7da6c 100644
--- a/meta/recipes-connectivity/openssh/openssh_8.2p1.bb
+++ b/meta/recipes-connectivity/openssh/openssh_8.2p1.bb
@@ -40,6 +40,7 @@ SRC_URI = "http://ftp.openbsd.org/pub/OpenBSD/OpenSSH/portable/openssh-${PV}.tar
            file://CVE-2023-38408-11.patch \
            file://CVE-2023-38408-12.patch \
            file://CVE-2023-48795.patch \
+           file://CVE-2023-51385.patch \
            "
 SRC_URI[md5sum] = "3076e6413e8dbe56d33848c1054ac091"
 SRC_URI[sha256sum] = "43925151e6cf6cee1450190c0e9af4dc36b41c12737619edff8bcebdff64e671"