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gssapi.8.4p1.patch
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gssapi.8.4p1.patch
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From d1b7918f9bce6e997c7952ac795e18d09192b2a6 Mon Sep 17 00:00:00 2001
From: Simon Wilkinson <simon@sxw.org.uk>
Date: Sun, 9 Feb 2014 16:09:48 +0000
Subject: GSSAPI key exchange support
This patch has been rejected upstream: "None of the OpenSSH developers are
in favour of adding this, and this situation has not changed for several
years. This is not a slight on Simon's patch, which is of fine quality, but
just that a) we don't trust GSSAPI implementations that much and b) we don't
like adding new KEX since they are pre-auth attack surface. This one is
particularly scary, since it requires hooks out to typically root-owned
system resources."
However, quite a lot of people rely on this in Debian, and it's better to
have it merged into the main openssh package rather than having separate
-krb5 packages (as we used to have). It seems to have a generally good
security history.
Author: Simon Wilkinson <simon@sxw.org.uk>
Author: Colin Watson <cjwatson@debian.org>
Author: Jakub Jelen <jjelen@redhat.com>
Origin: other, https://github.com/openssh-gsskex/openssh-gsskex/commits/debian/master
Bug: https://bugzilla.mindrot.org/show_bug.cgi?id=1242
Last-Updated: 2020-06-07
Patch-Name: gssapi.patch
---
Makefile.in | 3 +-
README.md | 33 +++
auth.c | 96 +-------
auth2-gss.c | 56 ++++-
auth2.c | 2 +
canohost.c | 93 ++++++++
canohost.h | 3 +
clientloop.c | 15 +-
configure.ac | 24 ++
gss-genr.c | 300 +++++++++++++++++++++++-
gss-serv-krb5.c | 85 ++++++-
gss-serv.c | 186 +++++++++++++--
kex.c | 66 +++++-
kex.h | 29 +++
kexdh.c | 10 +
kexgen.c | 2 +-
kexgssc.c | 606 ++++++++++++++++++++++++++++++++++++++++++++++++
kexgsss.c | 474 +++++++++++++++++++++++++++++++++++++
monitor.c | 139 ++++++++++-
monitor.h | 2 +
monitor_wrap.c | 57 ++++-
monitor_wrap.h | 4 +-
readconf.c | 70 ++++++
readconf.h | 6 +
servconf.c | 47 ++++
servconf.h | 3 +
session.c | 10 +-
ssh-gss.h | 54 ++++-
ssh.1 | 8 +
ssh.c | 6 +-
ssh_config | 2 +
ssh_config.5 | 57 +++++
sshconnect2.c | 154 +++++++++++-
sshd.c | 62 ++++-
sshd_config | 2 +
sshd_config.5 | 30 +++
sshkey.c | 3 +-
sshkey.h | 1 +
38 files changed, 2640 insertions(+), 160 deletions(-)
create mode 100644 kexgssc.c
create mode 100644 kexgsss.c
diff --git a/Makefile.in b/Makefile.in
index acfb919da..56759c388 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -107,6 +107,7 @@ LIBSSH_OBJS=${LIBOPENSSH_OBJS} \
kex.o kexdh.o kexgex.o kexecdh.o kexc25519.o \
kexgexc.o kexgexs.o \
sntrup4591761.o kexsntrup4591761x25519.o kexgen.o \
+ kexgssc.o \
sftp-realpath.o platform-pledge.o platform-tracing.o platform-misc.o \
sshbuf-io.o
@@ -123,7 +124,7 @@ SSHDOBJS=sshd.o auth-rhosts.o auth-passwd.o \
auth-bsdauth.o auth2-hostbased.o auth2-kbdint.o \
auth2-none.o auth2-passwd.o auth2-pubkey.o \
monitor.o monitor_wrap.o auth-krb5.o \
- auth2-gss.o gss-serv.o gss-serv-krb5.o \
+ auth2-gss.o gss-serv.o gss-serv-krb5.o kexgsss.o \
loginrec.o auth-pam.o auth-shadow.o auth-sia.o md5crypt.o \
sftp-server.o sftp-common.o \
sandbox-null.o sandbox-rlimit.o sandbox-systrace.o sandbox-darwin.o \
diff --git a/README.md b/README.md
index 28fb43d2a..5b73d24c0 100644
--- a/README.md
+++ b/README.md
@@ -1,3 +1,36 @@
+Portable OpenSSH with GSSAPI Key Exchange patches
+=================================================
+
+Currently, there are two branches with gssapi key exchange related
+patches:
+
+ * fedora/master: Changes that are shipped in Fedora
+ * debian/master: Changes that are shipped in Debian
+
+The target is to converge to a shared repository with single master
+branch from where we could build releases for both OSes.
+
+
+What is in:
+
+ * The original patch implementing missing parts of RFC4462 by Simon Wilkinson
+ adapted to the current OpenSSH versions and with several fixes
+ * New methods for GSSAPI Kex from IETF draft [1] from Jakub Jelen
+
+
+Missing kerberos-related parts:
+
+ * .k5login and .kusers support available in Fedora [2] [3].
+ * Improved handling of kerberos ccache location [4]
+
+
+[1] https://tools.ietf.org/html/draft-ietf-curdle-gss-keyex-sha2-08
+[2] https://src.fedoraproject.org/rpms/openssh/blob/master/f/openssh-6.6p1-kuserok.patch
+[3] https://src.fedoraproject.org/rpms/openssh/blob/master/f/openssh-6.6p1-GSSAPIEnablek5users.patch
+[4] https://bugzilla.mindrot.org/show_bug.cgi?id=2775
+
+-------------------------------------------------------------------------------
+
# Portable OpenSSH
[](https://bugs.chromium.org/p/oss-fuzz/issues/list?sort=-opened&can=1&q=proj:openssh)
diff --git a/auth.c b/auth.c
index 9a5498b66..3d31ec860 100644
--- a/auth.c
+++ b/auth.c
@@ -400,7 +400,8 @@ auth_root_allowed(struct ssh *ssh, const char *method)
case PERMIT_NO_PASSWD:
if (strcmp(method, "publickey") == 0 ||
strcmp(method, "hostbased") == 0 ||
- strcmp(method, "gssapi-with-mic") == 0)
+ strcmp(method, "gssapi-with-mic") == 0 ||
+ strcmp(method, "gssapi-keyex") == 0)
return 1;
break;
case PERMIT_FORCED_ONLY:
@@ -724,99 +725,6 @@ fakepw(void)
return (&fake);
}
-/*
- * Returns the remote DNS hostname as a string. The returned string must not
- * be freed. NB. this will usually trigger a DNS query the first time it is
- * called.
- * This function does additional checks on the hostname to mitigate some
- * attacks on legacy rhosts-style authentication.
- * XXX is RhostsRSAAuthentication vulnerable to these?
- * XXX Can we remove these checks? (or if not, remove RhostsRSAAuthentication?)
- */
-
-static char *
-remote_hostname(struct ssh *ssh)
-{
- struct sockaddr_storage from;
- socklen_t fromlen;
- struct addrinfo hints, *ai, *aitop;
- char name[NI_MAXHOST], ntop2[NI_MAXHOST];
- const char *ntop = ssh_remote_ipaddr(ssh);
-
- /* Get IP address of client. */
- fromlen = sizeof(from);
- memset(&from, 0, sizeof(from));
- if (getpeername(ssh_packet_get_connection_in(ssh),
- (struct sockaddr *)&from, &fromlen) == -1) {
- debug("getpeername failed: %.100s", strerror(errno));
- return xstrdup(ntop);
- }
-
- ipv64_normalise_mapped(&from, &fromlen);
- if (from.ss_family == AF_INET6)
- fromlen = sizeof(struct sockaddr_in6);
-
- debug3("Trying to reverse map address %.100s.", ntop);
- /* Map the IP address to a host name. */
- if (getnameinfo((struct sockaddr *)&from, fromlen, name, sizeof(name),
- NULL, 0, NI_NAMEREQD) != 0) {
- /* Host name not found. Use ip address. */
- return xstrdup(ntop);
- }
-
- /*
- * if reverse lookup result looks like a numeric hostname,
- * someone is trying to trick us by PTR record like following:
- * 1.1.1.10.in-addr.arpa. IN PTR 2.3.4.5
- */
- memset(&hints, 0, sizeof(hints));
- hints.ai_socktype = SOCK_DGRAM; /*dummy*/
- hints.ai_flags = AI_NUMERICHOST;
- if (getaddrinfo(name, NULL, &hints, &ai) == 0) {
- logit("Nasty PTR record \"%s\" is set up for %s, ignoring",
- name, ntop);
- freeaddrinfo(ai);
- return xstrdup(ntop);
- }
-
- /* Names are stored in lowercase. */
- lowercase(name);
-
- /*
- * Map it back to an IP address and check that the given
- * address actually is an address of this host. This is
- * necessary because anyone with access to a name server can
- * define arbitrary names for an IP address. Mapping from
- * name to IP address can be trusted better (but can still be
- * fooled if the intruder has access to the name server of
- * the domain).
- */
- memset(&hints, 0, sizeof(hints));
- hints.ai_family = from.ss_family;
- hints.ai_socktype = SOCK_STREAM;
- if (getaddrinfo(name, NULL, &hints, &aitop) != 0) {
- logit("reverse mapping checking getaddrinfo for %.700s "
- "[%s] failed.", name, ntop);
- return xstrdup(ntop);
- }
- /* Look for the address from the list of addresses. */
- for (ai = aitop; ai; ai = ai->ai_next) {
- if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop2,
- sizeof(ntop2), NULL, 0, NI_NUMERICHOST) == 0 &&
- (strcmp(ntop, ntop2) == 0))
- break;
- }
- freeaddrinfo(aitop);
- /* If we reached the end of the list, the address was not there. */
- if (ai == NULL) {
- /* Address not found for the host name. */
- logit("Address %.100s maps to %.600s, but this does not "
- "map back to the address.", ntop, name);
- return xstrdup(ntop);
- }
- return xstrdup(name);
-}
-
/*
* Return the canonical name of the host in the other side of the current
* connection. The host name is cached, so it is efficient to call this
diff --git a/auth2-gss.c b/auth2-gss.c
index 9351e0428..d6446c0cf 100644
--- a/auth2-gss.c
+++ b/auth2-gss.c
@@ -1,7 +1,7 @@
/* $OpenBSD: auth2-gss.c,v 1.29 2018/07/31 03:10:27 djm Exp $ */
/*
- * Copyright (c) 2001-2003 Simon Wilkinson. All rights reserved.
+ * Copyright (c) 2001-2007 Simon Wilkinson. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
@@ -54,6 +54,48 @@ static int input_gssapi_mic(int type, u_int32_t plen, struct ssh *ssh);
static int input_gssapi_exchange_complete(int type, u_int32_t plen, struct ssh *ssh);
static int input_gssapi_errtok(int, u_int32_t, struct ssh *);
+/*
+ * The 'gssapi_keyex' userauth mechanism.
+ */
+static int
+userauth_gsskeyex(struct ssh *ssh)
+{
+ Authctxt *authctxt = ssh->authctxt;
+ int r, authenticated = 0;
+ struct sshbuf *b = NULL;
+ gss_buffer_desc mic, gssbuf;
+ u_char *p;
+ size_t len;
+
+ if ((r = sshpkt_get_string(ssh, &p, &len)) != 0 ||
+ (r = sshpkt_get_end(ssh)) != 0)
+ fatal("%s: %s", __func__, ssh_err(r));
+
+ if ((b = sshbuf_new()) == NULL)
+ fatal("%s: sshbuf_new failed", __func__);
+
+ mic.value = p;
+ mic.length = len;
+
+ ssh_gssapi_buildmic(b, authctxt->user, authctxt->service,
+ "gssapi-keyex");
+
+ if ((gssbuf.value = sshbuf_mutable_ptr(b)) == NULL)
+ fatal("%s: sshbuf_mutable_ptr failed", __func__);
+ gssbuf.length = sshbuf_len(b);
+
+ /* gss_kex_context is NULL with privsep, so we can't check it here */
+ if (!GSS_ERROR(PRIVSEP(ssh_gssapi_checkmic(gss_kex_context,
+ &gssbuf, &mic))))
+ authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user,
+ authctxt->pw, 1));
+
+ sshbuf_free(b);
+ free(mic.value);
+
+ return (authenticated);
+}
+
/*
* We only support those mechanisms that we know about (ie ones that we know
* how to check local user kuserok and the like)
@@ -260,7 +302,8 @@ input_gssapi_exchange_complete(int type, u_int32_t plen, struct ssh *ssh)
if ((r = sshpkt_get_end(ssh)) != 0)
fatal("%s: %s", __func__, ssh_err(r));
- authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));
+ authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user,
+ authctxt->pw, 1));
if ((!use_privsep || mm_is_monitor()) &&
(displayname = ssh_gssapi_displayname()) != NULL)
@@ -306,7 +349,8 @@ input_gssapi_mic(int type, u_int32_t plen, struct ssh *ssh)
gssbuf.length = sshbuf_len(b);
if (!GSS_ERROR(PRIVSEP(ssh_gssapi_checkmic(gssctxt, &gssbuf, &mic))))
- authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));
+ authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user,
+ authctxt->pw, 0));
else
logit("GSSAPI MIC check failed");
@@ -326,6 +370,12 @@ input_gssapi_mic(int type, u_int32_t plen, struct ssh *ssh)
return 0;
}
+Authmethod method_gsskeyex = {
+ "gssapi-keyex",
+ userauth_gsskeyex,
+ &options.gss_authentication
+};
+
Authmethod method_gssapi = {
"gssapi-with-mic",
userauth_gssapi,
diff --git a/auth2.c b/auth2.c
index 242a7adbe..9fa1404b3 100644
--- a/auth2.c
+++ b/auth2.c
@@ -73,6 +73,7 @@ extern Authmethod method_passwd;
extern Authmethod method_kbdint;
extern Authmethod method_hostbased;
#ifdef GSSAPI
+extern Authmethod method_gsskeyex;
extern Authmethod method_gssapi;
#endif
@@ -80,6 +81,7 @@ Authmethod *authmethods[] = {
&method_none,
&method_pubkey,
#ifdef GSSAPI
+ &method_gsskeyex,
&method_gssapi,
#endif
&method_passwd,
diff --git a/canohost.c b/canohost.c
index abea9c6e6..8e81b5193 100644
--- a/canohost.c
+++ b/canohost.c
@@ -35,6 +35,99 @@
#include "canohost.h"
#include "misc.h"
+/*
+ * Returns the remote DNS hostname as a string. The returned string must not
+ * be freed. NB. this will usually trigger a DNS query the first time it is
+ * called.
+ * This function does additional checks on the hostname to mitigate some
+ * attacks on legacy rhosts-style authentication.
+ * XXX is RhostsRSAAuthentication vulnerable to these?
+ * XXX Can we remove these checks? (or if not, remove RhostsRSAAuthentication?)
+ */
+
+char *
+remote_hostname(struct ssh *ssh)
+{
+ struct sockaddr_storage from;
+ socklen_t fromlen;
+ struct addrinfo hints, *ai, *aitop;
+ char name[NI_MAXHOST], ntop2[NI_MAXHOST];
+ const char *ntop = ssh_remote_ipaddr(ssh);
+
+ /* Get IP address of client. */
+ fromlen = sizeof(from);
+ memset(&from, 0, sizeof(from));
+ if (getpeername(ssh_packet_get_connection_in(ssh),
+ (struct sockaddr *)&from, &fromlen) == -1) {
+ debug("getpeername failed: %.100s", strerror(errno));
+ return xstrdup(ntop);
+ }
+
+ ipv64_normalise_mapped(&from, &fromlen);
+ if (from.ss_family == AF_INET6)
+ fromlen = sizeof(struct sockaddr_in6);
+
+ debug3("Trying to reverse map address %.100s.", ntop);
+ /* Map the IP address to a host name. */
+ if (getnameinfo((struct sockaddr *)&from, fromlen, name, sizeof(name),
+ NULL, 0, NI_NAMEREQD) != 0) {
+ /* Host name not found. Use ip address. */
+ return xstrdup(ntop);
+ }
+
+ /*
+ * if reverse lookup result looks like a numeric hostname,
+ * someone is trying to trick us by PTR record like following:
+ * 1.1.1.10.in-addr.arpa. IN PTR 2.3.4.5
+ */
+ memset(&hints, 0, sizeof(hints));
+ hints.ai_socktype = SOCK_DGRAM; /*dummy*/
+ hints.ai_flags = AI_NUMERICHOST;
+ if (getaddrinfo(name, NULL, &hints, &ai) == 0) {
+ logit("Nasty PTR record \"%s\" is set up for %s, ignoring",
+ name, ntop);
+ freeaddrinfo(ai);
+ return xstrdup(ntop);
+ }
+
+ /* Names are stored in lowercase. */
+ lowercase(name);
+
+ /*
+ * Map it back to an IP address and check that the given
+ * address actually is an address of this host. This is
+ * necessary because anyone with access to a name server can
+ * define arbitrary names for an IP address. Mapping from
+ * name to IP address can be trusted better (but can still be
+ * fooled if the intruder has access to the name server of
+ * the domain).
+ */
+ memset(&hints, 0, sizeof(hints));
+ hints.ai_family = from.ss_family;
+ hints.ai_socktype = SOCK_STREAM;
+ if (getaddrinfo(name, NULL, &hints, &aitop) != 0) {
+ logit("reverse mapping checking getaddrinfo for %.700s "
+ "[%s] failed.", name, ntop);
+ return xstrdup(ntop);
+ }
+ /* Look for the address from the list of addresses. */
+ for (ai = aitop; ai; ai = ai->ai_next) {
+ if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop2,
+ sizeof(ntop2), NULL, 0, NI_NUMERICHOST) == 0 &&
+ (strcmp(ntop, ntop2) == 0))
+ break;
+ }
+ freeaddrinfo(aitop);
+ /* If we reached the end of the list, the address was not there. */
+ if (ai == NULL) {
+ /* Address not found for the host name. */
+ logit("Address %.100s maps to %.600s, but this does not "
+ "map back to the address.", ntop, name);
+ return xstrdup(ntop);
+ }
+ return xstrdup(name);
+}
+
void
ipv64_normalise_mapped(struct sockaddr_storage *addr, socklen_t *len)
{
diff --git a/canohost.h b/canohost.h
index 26d62855a..0cadc9f18 100644
--- a/canohost.h
+++ b/canohost.h
@@ -15,6 +15,9 @@
#ifndef _CANOHOST_H
#define _CANOHOST_H
+struct ssh;
+
+char *remote_hostname(struct ssh *);
char *get_peer_ipaddr(int);
int get_peer_port(int);
char *get_local_ipaddr(int);
diff --git a/clientloop.c b/clientloop.c
index 60b46d161..2cebea29f 100644
--- a/clientloop.c
+++ b/clientloop.c
@@ -112,6 +112,10 @@
#include "ssherr.h"
#include "hostfile.h"
+#ifdef GSSAPI
+#include "ssh-gss.h"
+#endif
+
/* import options */
extern Options options;
@@ -1368,9 +1372,18 @@ client_loop(struct ssh *ssh, int have_pty, int escape_char_arg,
break;
/* Do channel operations unless rekeying in progress. */
- if (!ssh_packet_is_rekeying(ssh))
+ if (!ssh_packet_is_rekeying(ssh)) {
channel_after_select(ssh, readset, writeset);
+#ifdef GSSAPI
+ if (options.gss_renewal_rekey &&
+ ssh_gssapi_credentials_updated(NULL)) {
+ debug("credentials updated - forcing rekey");
+ need_rekeying = 1;
+ }
+#endif
+ }
+
/* Buffer input from the connection. */
client_process_net_input(ssh, readset);
diff --git a/configure.ac b/configure.ac
index 7005a503e..c8a96deb4 100644
--- a/configure.ac
+++ b/configure.ac
@@ -679,6 +679,30 @@ main() { if (NSVersionOfRunTimeLibrary("System") >= (60 << 16))
[Use tunnel device compatibility to OpenBSD])
AC_DEFINE([SSH_TUN_PREPEND_AF], [1],
[Prepend the address family to IP tunnel traffic])
+ AC_MSG_CHECKING([if we have the Security Authorization Session API])
+ AC_TRY_COMPILE([#include <Security/AuthSession.h>],
+ [SessionCreate(0, 0);],
+ [ac_cv_use_security_session_api="yes"
+ AC_DEFINE([USE_SECURITY_SESSION_API], [1],
+ [platform has the Security Authorization Session API])
+ LIBS="$LIBS -framework Security"
+ AC_MSG_RESULT([yes])],
+ [ac_cv_use_security_session_api="no"
+ AC_MSG_RESULT([no])])
+ AC_MSG_CHECKING([if we have an in-memory credentials cache])
+ AC_TRY_COMPILE(
+ [#include <Kerberos/Kerberos.h>],
+ [cc_context_t c;
+ (void) cc_initialize (&c, 0, NULL, NULL);],
+ [AC_DEFINE([USE_CCAPI], [1],
+ [platform uses an in-memory credentials cache])
+ LIBS="$LIBS -framework Security"
+ AC_MSG_RESULT([yes])
+ if test "x$ac_cv_use_security_session_api" = "xno"; then
+ AC_MSG_ERROR([*** Need a security framework to use the credentials cache API ***])
+ fi],
+ [AC_MSG_RESULT([no])]
+ )
m4_pattern_allow([AU_IPv])
AC_CHECK_DECL([AU_IPv4], [],
AC_DEFINE([AU_IPv4], [0], [System only supports IPv4 audit records])
diff --git a/gss-genr.c b/gss-genr.c
index d56257b4a..763a63ffa 100644
--- a/gss-genr.c
+++ b/gss-genr.c
@@ -1,7 +1,7 @@
/* $OpenBSD: gss-genr.c,v 1.26 2018/07/10 09:13:30 djm Exp $ */
/*
- * Copyright (c) 2001-2007 Simon Wilkinson. All rights reserved.
+ * Copyright (c) 2001-2009 Simon Wilkinson. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
@@ -41,12 +41,36 @@
#include "sshbuf.h"
#include "log.h"
#include "ssh2.h"
+#include "cipher.h"
+#include "sshkey.h"
+#include "kex.h"
+#include "digest.h"
+#include "packet.h"
#include "ssh-gss.h"
extern u_char *session_id2;
extern u_int session_id2_len;
+typedef struct {
+ char *encoded;
+ gss_OID oid;
+} ssh_gss_kex_mapping;
+
+/*
+ * XXX - It would be nice to find a more elegant way of handling the
+ * XXX passing of the key exchange context to the userauth routines
+ */
+
+Gssctxt *gss_kex_context = NULL;
+
+static ssh_gss_kex_mapping *gss_enc2oid = NULL;
+
+int
+ssh_gssapi_oid_table_ok(void) {
+ return (gss_enc2oid != NULL);
+}
+
/* sshbuf_get for gss_buffer_desc */
int
ssh_gssapi_get_buffer_desc(struct sshbuf *b, gss_buffer_desc *g)
@@ -62,6 +86,162 @@ ssh_gssapi_get_buffer_desc(struct sshbuf *b, gss_buffer_desc *g)
return 0;
}
+/* sshpkt_get of gss_buffer_desc */
+int
+ssh_gssapi_sshpkt_get_buffer_desc(struct ssh *ssh, gss_buffer_desc *g)
+{
+ int r;
+ u_char *p;
+ size_t len;
+
+ if ((r = sshpkt_get_string(ssh, &p, &len)) != 0)
+ return r;
+ g->value = p;
+ g->length = len;
+ return 0;
+}
+
+/*
+ * Return a list of the gss-group1-sha1 mechanisms supported by this program
+ *
+ * We test mechanisms to ensure that we can use them, to avoid starting
+ * a key exchange with a bad mechanism
+ */
+
+char *
+ssh_gssapi_client_mechanisms(const char *host, const char *client,
+ const char *kex) {
+ gss_OID_set gss_supported = NULL;
+ OM_uint32 min_status;
+
+ if (GSS_ERROR(gss_indicate_mechs(&min_status, &gss_supported)))
+ return NULL;
+
+ return ssh_gssapi_kex_mechs(gss_supported, ssh_gssapi_check_mechanism,
+ host, client, kex);
+}
+
+char *
+ssh_gssapi_kex_mechs(gss_OID_set gss_supported, ssh_gssapi_check_fn *check,
+ const char *host, const char *client, const char *kex) {
+ struct sshbuf *buf = NULL;
+ size_t i;
+ int r = SSH_ERR_ALLOC_FAIL;
+ int oidpos, enclen;
+ char *mechs, *encoded;
+ u_char digest[SSH_DIGEST_MAX_LENGTH];
+ char deroid[2];
+ struct ssh_digest_ctx *md = NULL;
+ char *s, *cp, *p;
+
+ if (gss_enc2oid != NULL) {
+ for (i = 0; gss_enc2oid[i].encoded != NULL; i++)
+ free(gss_enc2oid[i].encoded);
+ free(gss_enc2oid);
+ }
+
+ gss_enc2oid = xmalloc(sizeof(ssh_gss_kex_mapping) *
+ (gss_supported->count + 1));
+
+ if ((buf = sshbuf_new()) == NULL)
+ fatal("%s: sshbuf_new failed", __func__);
+
+ oidpos = 0;
+ s = cp = xstrdup(kex);
+ for (i = 0; i < gss_supported->count; i++) {
+ if (gss_supported->elements[i].length < 128 &&
+ (*check)(NULL, &(gss_supported->elements[i]), host, client)) {
+
+ deroid[0] = SSH_GSS_OIDTYPE;
+ deroid[1] = gss_supported->elements[i].length;
+
+ if ((md = ssh_digest_start(SSH_DIGEST_MD5)) == NULL ||
+ (r = ssh_digest_update(md, deroid, 2)) != 0 ||
+ (r = ssh_digest_update(md,
+ gss_supported->elements[i].elements,
+ gss_supported->elements[i].length)) != 0 ||
+ (r = ssh_digest_final(md, digest, sizeof(digest))) != 0)
+ fatal("%s: digest failed: %s", __func__,
+ ssh_err(r));
+ ssh_digest_free(md);
+ md = NULL;
+
+ encoded = xmalloc(ssh_digest_bytes(SSH_DIGEST_MD5)
+ * 2);
+ enclen = __b64_ntop(digest,
+ ssh_digest_bytes(SSH_DIGEST_MD5), encoded,
+ ssh_digest_bytes(SSH_DIGEST_MD5) * 2);
+
+ cp = strncpy(s, kex, strlen(kex));
+ for ((p = strsep(&cp, ",")); p && *p != '\0';
+ (p = strsep(&cp, ","))) {
+ if (sshbuf_len(buf) != 0 &&
+ (r = sshbuf_put_u8(buf, ',')) != 0)
+ fatal("%s: sshbuf_put_u8 error: %s",
+ __func__, ssh_err(r));
+ if ((r = sshbuf_put(buf, p, strlen(p))) != 0 ||
+ (r = sshbuf_put(buf, encoded, enclen)) != 0)
+ fatal("%s: sshbuf_put error: %s",
+ __func__, ssh_err(r));
+ }
+
+ gss_enc2oid[oidpos].oid = &(gss_supported->elements[i]);
+ gss_enc2oid[oidpos].encoded = encoded;
+ oidpos++;
+ }
+ }
+ free(s);
+ gss_enc2oid[oidpos].oid = NULL;
+ gss_enc2oid[oidpos].encoded = NULL;
+
+ if ((mechs = sshbuf_dup_string(buf)) == NULL)
+ fatal("%s: sshbuf_dup_string failed", __func__);
+
+ sshbuf_free(buf);
+
+ if (strlen(mechs) == 0) {
+ free(mechs);
+ mechs = NULL;
+ }
+
+ return (mechs);
+}
+
+gss_OID
+ssh_gssapi_id_kex(Gssctxt *ctx, char *name, int kex_type) {
+ int i = 0;
+
+#define SKIP_KEX_NAME(type) \
+ case type: \
+ if (strlen(name) < sizeof(type##_ID)) \
+ return GSS_C_NO_OID; \
+ name += sizeof(type##_ID) - 1; \
+ break;
+
+ switch (kex_type) {
+ SKIP_KEX_NAME(KEX_GSS_GRP1_SHA1)
+ SKIP_KEX_NAME(KEX_GSS_GRP14_SHA1)
+ SKIP_KEX_NAME(KEX_GSS_GRP14_SHA256)
+ SKIP_KEX_NAME(KEX_GSS_GRP16_SHA512)
+ SKIP_KEX_NAME(KEX_GSS_GEX_SHA1)
+ SKIP_KEX_NAME(KEX_GSS_NISTP256_SHA256)
+ SKIP_KEX_NAME(KEX_GSS_C25519_SHA256)
+ default:
+ return GSS_C_NO_OID;
+ }
+
+#undef SKIP_KEX_NAME
+
+ while (gss_enc2oid[i].encoded != NULL &&
+ strcmp(name, gss_enc2oid[i].encoded) != 0)
+ i++;
+
+ if (gss_enc2oid[i].oid != NULL && ctx != NULL)
+ ssh_gssapi_set_oid(ctx, gss_enc2oid[i].oid);
+
+ return gss_enc2oid[i].oid;
+}
+
/* Check that the OID in a data stream matches that in the context */
int
ssh_gssapi_check_oid(Gssctxt *ctx, void *data, size_t len)
@@ -218,7 +398,7 @@ ssh_gssapi_init_ctx(Gssctxt *ctx, int deleg_creds, gss_buffer_desc *recv_tok,
}
ctx->major = gss_init_sec_context(&ctx->minor,
- GSS_C_NO_CREDENTIAL, &ctx->context, ctx->name, ctx->oid,
+ ctx->client_creds, &ctx->context, ctx->name, ctx->oid,
GSS_C_MUTUAL_FLAG | GSS_C_INTEG_FLAG | deleg_flag,
0, NULL, recv_tok, NULL, send_tok, flags, NULL);
@@ -247,9 +427,43 @@ ssh_gssapi_import_name(Gssctxt *ctx, const char *host)
return (ctx->major);
}
+OM_uint32
+ssh_gssapi_client_identity(Gssctxt *ctx, const char *name)
+{
+ gss_buffer_desc gssbuf;
+ gss_name_t gssname;
+ OM_uint32 status;
+ gss_OID_set oidset;
+
+ gssbuf.value = (void *) name;
+ gssbuf.length = strlen(gssbuf.value);
+
+ gss_create_empty_oid_set(&status, &oidset);
+ gss_add_oid_set_member(&status, ctx->oid, &oidset);
+
+ ctx->major = gss_import_name(&ctx->minor, &gssbuf,
+ GSS_C_NT_USER_NAME, &gssname);
+
+ if (!ctx->major)
+ ctx->major = gss_acquire_cred(&ctx->minor,
+ gssname, 0, oidset, GSS_C_INITIATE,
+ &ctx->client_creds, NULL, NULL);
+
+ gss_release_name(&status, &gssname);
+ gss_release_oid_set(&status, &oidset);
+
+ if (ctx->major)
+ ssh_gssapi_error(ctx);
+
+ return(ctx->major);
+}
+
OM_uint32
ssh_gssapi_sign(Gssctxt *ctx, gss_buffer_t buffer, gss_buffer_t hash)
{
+ if (ctx == NULL)
+ return -1;
+
if ((ctx->major = gss_get_mic(&ctx->minor, ctx->context,
GSS_C_QOP_DEFAULT, buffer, hash)))
ssh_gssapi_error(ctx);
@@ -257,6 +471,19 @@ ssh_gssapi_sign(Gssctxt *ctx, gss_buffer_t buffer, gss_buffer_t hash)
return (ctx->major);
}
+/* Priviledged when used by server */
+OM_uint32
+ssh_gssapi_checkmic(Gssctxt *ctx, gss_buffer_t gssbuf, gss_buffer_t gssmic)
+{
+ if (ctx == NULL)
+ return -1;
+
+ ctx->major = gss_verify_mic(&ctx->minor, ctx->context,
+ gssbuf, gssmic, NULL);
+
+ return (ctx->major);
+}
+
void
ssh_gssapi_buildmic(struct sshbuf *b, const char *user, const char *service,
const char *context)
@@ -273,11 +500,16 @@ ssh_gssapi_buildmic(struct sshbuf *b, const char *user, const char *service,
}
int
-ssh_gssapi_check_mechanism(Gssctxt **ctx, gss_OID oid, const char *host)
+ssh_gssapi_check_mechanism(Gssctxt **ctx, gss_OID oid, const char *host,
+ const char *client)
{
gss_buffer_desc token = GSS_C_EMPTY_BUFFER;
OM_uint32 major, minor;
gss_OID_desc spnego_oid = {6, (void *)"\x2B\x06\x01\x05\x05\x02"};
+ Gssctxt *intctx = NULL;
+
+ if (ctx == NULL)
+ ctx = &intctx;
/* RFC 4462 says we MUST NOT do SPNEGO */
if (oid->length == spnego_oid.length &&
@@ -287,6 +519,10 @@ ssh_gssapi_check_mechanism(Gssctxt **ctx, gss_OID oid, const char *host)
ssh_gssapi_build_ctx(ctx);
ssh_gssapi_set_oid(*ctx, oid);
major = ssh_gssapi_import_name(*ctx, host);
+
+ if (!GSS_ERROR(major) && client)
+ major = ssh_gssapi_client_identity(*ctx, client);
+
if (!GSS_ERROR(major)) {
major = ssh_gssapi_init_ctx(*ctx, 0, GSS_C_NO_BUFFER, &token,
NULL);
@@ -296,10 +532,66 @@ ssh_gssapi_check_mechanism(Gssctxt **ctx, gss_OID oid, const char *host)
GSS_C_NO_BUFFER);
}
- if (GSS_ERROR(major))
+ if (GSS_ERROR(major) || intctx != NULL)
ssh_gssapi_delete_ctx(ctx);
return (!GSS_ERROR(major));
}
+int
+ssh_gssapi_credentials_updated(Gssctxt *ctxt) {
+ static gss_name_t saved_name = GSS_C_NO_NAME;
+ static OM_uint32 saved_lifetime = 0;
+ static gss_OID saved_mech = GSS_C_NO_OID;
+ static gss_name_t name;
+ static OM_uint32 last_call = 0;
+ OM_uint32 lifetime, now, major, minor;
+ int equal;
+
+ now = time(NULL);
+
+ if (ctxt) {
+ debug("Rekey has happened - updating saved versions");
+
+ if (saved_name != GSS_C_NO_NAME)
+ gss_release_name(&minor, &saved_name);
+
+ major = gss_inquire_cred(&minor, GSS_C_NO_CREDENTIAL,
+ &saved_name, &saved_lifetime, NULL, NULL);
+
+ if (!GSS_ERROR(major)) {
+ saved_mech = ctxt->oid;
+ saved_lifetime+= now;
+ } else {
+ /* Handle the error */
+ }
+ return 0;
+ }
+
+ if (now - last_call < 10)
+ return 0;
+
+ last_call = now;
+
+ if (saved_mech == GSS_C_NO_OID)
+ return 0;
+
+ major = gss_inquire_cred(&minor, GSS_C_NO_CREDENTIAL,
+ &name, &lifetime, NULL, NULL);
+ if (major == GSS_S_CREDENTIALS_EXPIRED)
+ return 0;
+ else if (GSS_ERROR(major))
+ return 0;
+
+ major = gss_compare_name(&minor, saved_name, name, &equal);
+ gss_release_name(&minor, &name);
+ if (GSS_ERROR(major))
+ return 0;
+
+ if (equal && (saved_lifetime < lifetime + now - 10))
+ return 1;
+
+ return 0;
+}
+
#endif /* GSSAPI */
diff --git a/gss-serv-krb5.c b/gss-serv-krb5.c
index a151bc1e4..ef9beb67c 100644
--- a/gss-serv-krb5.c
+++ b/gss-serv-krb5.c
@@ -1,7 +1,7 @@
/* $OpenBSD: gss-serv-krb5.c,v 1.9 2018/07/09 21:37:55 markus Exp $ */
/*
- * Copyright (c) 2001-2003 Simon Wilkinson. All rights reserved.
+ * Copyright (c) 2001-2007 Simon Wilkinson. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
@@ -120,8 +120,8 @@ ssh_gssapi_krb5_storecreds(ssh_gssapi_client *client)
krb5_error_code problem;
krb5_principal princ;
OM_uint32 maj_status, min_status;
- int len;
const char *errmsg;
+ const char *new_ccname;
if (client->creds == NULL) {
debug("No credentials stored");
@@ -180,11 +180,16 @@ ssh_gssapi_krb5_storecreds(ssh_gssapi_client *client)
return;
}
- client->store.filename = xstrdup(krb5_cc_get_name(krb_context, ccache));
+ new_ccname = krb5_cc_get_name(krb_context, ccache);
+
client->store.envvar = "KRB5CCNAME";
- len = strlen(client->store.filename) + 6;
- client->store.envval = xmalloc(len);
- snprintf(client->store.envval, len, "FILE:%s", client->store.filename);
+#ifdef USE_CCAPI
+ xasprintf(&client->store.envval, "API:%s", new_ccname);
+ client->store.filename = NULL;
+#else
+ xasprintf(&client->store.envval, "FILE:%s", new_ccname);
+ client->store.filename = xstrdup(new_ccname);
+#endif
#ifdef USE_PAM
if (options.use_pam)
@@ -196,6 +201,71 @@ ssh_gssapi_krb5_storecreds(ssh_gssapi_client *client)
return;
}
+int
+ssh_gssapi_krb5_updatecreds(ssh_gssapi_ccache *store,
+ ssh_gssapi_client *client)
+{
+ krb5_ccache ccache = NULL;
+ krb5_principal principal = NULL;
+ char *name = NULL;
+ krb5_error_code problem;
+ OM_uint32 maj_status, min_status;
+
+ if ((problem = krb5_cc_resolve(krb_context, store->envval, &ccache))) {
+ logit("krb5_cc_resolve(): %.100s",
+ krb5_get_err_text(krb_context, problem));
+ return 0;
+ }
+
+ /* Find out who the principal in this cache is */
+ if ((problem = krb5_cc_get_principal(krb_context, ccache,
+ &principal))) {
+ logit("krb5_cc_get_principal(): %.100s",
+ krb5_get_err_text(krb_context, problem));