Apply upstream fix for CVE-2016-10009 and CVE-2016-10010:

  add a whitelist of paths from which ssh-agent will load (via
  ssh-pkcs11-helper) a PKCS#11 module; ok markus@

  disable Unix-domain socket forwarding when privsep is disabled

(Note that this is a backport of upstream fixes, and this commit
is mainly to ease future imports).

Obtained from:  OpenBSD

serverloop.c

@@ -995,7 +995,7 @@ server_request_direct_streamlocal(void)
 
 	/* XXX fine grained permissions */
 	if ((options.allow_streamlocal_forwarding & FORWARD_LOCAL) != 0 &&
-	    !no_port_forwarding_flag) {
+	    !no_port_forwarding_flag && use_privsep) {
 		c = channel_connect_to_path(target,
 		    "direct-streamlocal@openssh.com", "direct-streamlocal");
 	} else {
@@ -1279,7 +1279,7 @@ server_input_global_request(int type, u_int32_t seq, void *ctxt)
 
 		/* check permissions */
 		if ((options.allow_streamlocal_forwarding & FORWARD_REMOTE) == 0
-		    || no_port_forwarding_flag) {
+		    || no_port_forwarding_flag || !use_privsep) {
 			success = 0;
 			packet_send_debug("Server has disabled port forwarding.");
 		} else {

ssh-agent.1

-.\" $OpenBSD: ssh-agent.1,v 1.62 2015/11/15 23:54:15 jmc Exp $
+.\" $OpenBSD: ssh-agent.1,v 1.63 2016/11/30 03:07:37 djm Exp $
 .\"
 .\" Author: Tatu Ylonen <ylo@cs.hut.fi>
 .\" Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -47,6 +47,7 @@
 .Op Fl a Ar bind_address
 .Op Fl E Ar fingerprint_hash
 .Op Fl t Ar life
+.Op Fl P Ar pkcs11_whitelist
 .Op Ar command Op Ar arg ...
 .Nm ssh-agent
 .Op Fl c | s
@@ -121,6 +122,18 @@ The default is
 Kill the current agent (given by the
 .Ev SSH_AGENT_PID
 environment variable).
+.It Fl P
+Specify a pattern-list of acceptable paths for PKCS#11 shared libraries
+that may be added using the
+.Fl s
+option to
+.Xr ssh-add 1 .
+The default is to allow loading PKCS#11 libraries from
+.Dq /usr/lib/*,/usr/local/lib/* .
+PKCS#11 libraries that do not match the whitelist will be refused.
+See PATTERNS in
+.Xr ssh_config 5
+for a description of pattern-list syntax.
 .It Fl s
 Generate Bourne shell commands on
 .Dv stdout .

ssh-agent.c

@@ -83,11 +83,16 @@
 #include "misc.h"
 #include "digest.h"
 #include "ssherr.h"
+#include "match.h"
 
 #ifdef ENABLE_PKCS11
 #include "ssh-pkcs11.h"
 #endif
 
+#ifndef DEFAULT_PKCS11_WHITELIST
+# define DEFAULT_PKCS11_WHITELIST "/usr/lib/*,/usr/local/lib/*"
+#endif
+
 #if defined(HAVE_SYS_PRCTL_H)
 #include <sys/prctl.h>	/* For prctl() and PR_SET_DUMPABLE */
 #endif
@@ -139,6 +144,9 @@ pid_t cleanup_pid = 0;
 char socket_name[PATH_MAX];
 char socket_dir[PATH_MAX];
 
+/* PKCS#11 path whitelist */
+static char *pkcs11_whitelist;
+
 /* locking */
 #define LOCK_SIZE	32
 #define LOCK_SALT_SIZE	16
@@ -741,7 +749,7 @@ no_identities(SocketEntry *e, u_int type)
 static void
 process_add_smartcard_key(SocketEntry *e)
 {
-	char *provider = NULL, *pin;
+	char *provider = NULL, *pin, canonical_provider[PATH_MAX];
 	int r, i, version, count = 0, success = 0, confirm = 0;
 	u_int seconds;
 	time_t death = 0;
@@ -773,10 +781,21 @@ process_add_smartcard_key(SocketEntry *e)
 			goto send;
 		}
 	}
+	if (realpath(provider, canonical_provider) == NULL) {
+		verbose("failed PKCS#11 add of \"%.100s\": realpath: %s",
+		    provider, strerror(errno));
+		goto send;
+	}
+	if (match_pattern_list(canonical_provider, pkcs11_whitelist, 0) != 1) {
+		verbose("refusing PKCS#11 add of \"%.100s\": "
+		    "provider not whitelisted", canonical_provider);
+		goto send;
+	}
+	debug("%s: add %.100s", __func__, canonical_provider);
 	if (lifetime && !death)
 		death = monotime() + lifetime;
 
-	count = pkcs11_add_provider(provider, pin, &keys);
+	count = pkcs11_add_provider(canonical_provider, pin, &keys);
 	for (i = 0; i < count; i++) {
 		k = keys[i];
 		version = k->type == KEY_RSA1 ? 1 : 2;
@@ -784,8 +803,8 @@ process_add_smartcard_key(SocketEntry *e)
 		if (lookup_identity(k, version) == NULL) {
 			id = xcalloc(1, sizeof(Identity));
 			id->key = k;
-			id->provider = xstrdup(provider);
-			id->comment = xstrdup(provider); /* XXX */
+			id->provider = xstrdup(canonical_provider);
+			id->comment = xstrdup(canonical_provider); /* XXX */
 			id->death = death;
 			id->confirm = confirm;
 			TAILQ_INSERT_TAIL(&tab->idlist, id, next);
@@ -1176,7 +1195,7 @@ usage(void)
 {
 	fprintf(stderr,
 	    "usage: ssh-agent [-c | -s] [-Dd] [-a bind_address] [-E fingerprint_hash]\n"
-	    "                 [-t life] [command [arg ...]]\n"
+	    "                 [-P pkcs11_whitelist] [-t life] [command [arg ...]]\n"
 	    "       ssh-agent [-c | -s] -k\n");
 	exit(1);
 }
@@ -1220,7 +1239,7 @@ main(int ac, char **av)
 	__progname = ssh_get_progname(av[0]);
 	seed_rng();
 
-	while ((ch = getopt(ac, av, "cDdksE:a:t:")) != -1) {
+	while ((ch = getopt(ac, av, "cDdksE:a:P:t:")) != -1) {
 		switch (ch) {
 		case 'E':
 			fingerprint_hash = ssh_digest_alg_by_name(optarg);
@@ -1235,6 +1254,11 @@ main(int ac, char **av)
 		case 'k':
 			k_flag++;
 			break;
+		case 'P':
+			if (pkcs11_whitelist != NULL)
+				fatal("-P option already specified");
+			pkcs11_whitelist = xstrdup(optarg);
+			break;
 		case 's':
 			if (c_flag)
 				usage();
@@ -1269,6 +1293,9 @@ main(int ac, char **av)
 	if (ac > 0 && (c_flag || k_flag || s_flag || d_flag || D_flag))
 		usage();
 
+	if (pkcs11_whitelist == NULL)
+		pkcs11_whitelist = xstrdup(DEFAULT_PKCS11_WHITELIST);
+
 	if (ac == 0 && !c_flag && !s_flag) {
 		shell = getenv("SHELL");
 		if (shell != NULL && (len = strlen(shell)) > 2 &&
@@ -1416,7 +1443,7 @@ main(int ac, char **av)
 	signal(SIGTERM, cleanup_handler);
 	nalloc = 0;
 
-	if (pledge("stdio cpath unix id proc exec", NULL) == -1)
+	if (pledge("stdio rpath cpath unix id proc exec", NULL) == -1)
 		fatal("%s: pledge: %s", __progname, strerror(errno));
 	platform_pledge_agent();