diff options
Diffstat (limited to 'debian/patches/CVE-2023-51385.patch')
| -rw-r--r-- | debian/patches/CVE-2023-51385.patch | 94 |
1 files changed, 94 insertions, 0 deletions
diff --git a/debian/patches/CVE-2023-51385.patch b/debian/patches/CVE-2023-51385.patch new file mode 100644 index 0000000..714c7a0 --- /dev/null +++ b/debian/patches/CVE-2023-51385.patch @@ -0,0 +1,94 @@ +From 14c4d6f0fa446414d1c38ad083107576d0ae3032 Mon Sep 17 00:00:00 2001 +From: "djm@openbsd.org" <djm@openbsd.org> +Date: Mon, 18 Dec 2023 14:47:44 +0000 +Subject: 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 + +Origin: backport, https://anongit.mindrot.org/openssh.git/commit/?id=7ef3787c84b6b524501211b11a26c742f829af1a +Last-Update: 2023-12-19 + +Patch-Name: CVE-2023-51385.patch +--- + ssh.c | 39 +++++++++++++++++++++++++++++++++++++++ + 1 file changed, 39 insertions(+) + +diff --git a/ssh.c b/ssh.c +index 8b6b54558..422405035 100644 +--- a/ssh.c ++++ b/ssh.c +@@ -623,6 +623,41 @@ ssh_conn_info_free(struct ssh_conn_info *cinfo) + free(cinfo); + } + ++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. + */ +@@ -1110,6 +1145,10 @@ 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"); + options.host_arg = xstrdup(host); + + /* Initialize the command to execute on remote host. */ |