From 0afbcf387fbfcc951caa5335e67b7b7eebffdaf9 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Petr=20P=C3=ADsa=C5=99?= Date: Mon, 14 Aug 2017 10:32:25 +0200 Subject: [PATCH] Fix CVE-2017-12836 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The hostname passed to RSH (ssh) client could be interpreted by OpenSSH client as an option and lead to local command execution. This fix adds no-more-options "--" separator before the hostname argument to the RSH client command. Original patch by Thorsten Glaser from ported to 1.11.23. Signed-off-by: Petr Písař --- src/client.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/src/client.c b/src/client.c index 2bef1a0..e87cda9 100644 --- a/src/client.c +++ b/src/client.c @@ -4839,7 +4839,7 @@ start_rsh_server (root, to_server, from_server) char *cvs_rsh; char *cvs_server = getenv ("CVS_SERVER"); int i = 0; - /* This needs to fit "rsh", "-b", "-l", "USER", "host", + /* This needs to fit "rsh", "-b", "-l", "USER", "--", "host", "cmd (w/ args)", and NULL. We leave some room to grow. */ char *rsh_argv[10]; @@ -4866,6 +4866,9 @@ start_rsh_server (root, to_server, from_server) rsh_argv[i++] = root->username; } + /* Only non-option arguments from here. (CVE-2017-12836) */ + rsh_argv[i++] = "--"; + rsh_argv[i++] = root->hostname; rsh_argv[i++] = cvs_server; rsh_argv[i++] = "server"; @@ -4944,6 +4947,8 @@ start_rsh_server (root, to_server, from_server) *p++ = root->username; } + *p++ = "--"; + *p++ = root->hostname; *p++ = command; *p++ = NULL; -- 2.9.5