openssh-portable/gss-genr.c

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/* $OpenBSD: gss-genr.c,v 1.29 2024/02/01 02:37:33 djm Exp $ */
/*
* 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
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR `AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "includes.h"
#ifdef GSSAPI
- deraadt@cvs.openbsd.org 2006/08/03 03:34:42 [OVERVIEW atomicio.c atomicio.h auth-bsdauth.c auth-chall.c auth-krb5.c] [auth-options.c auth-options.h auth-passwd.c auth-rh-rsa.c auth-rhosts.c] [auth-rsa.c auth-skey.c auth.c auth.h auth1.c auth2-chall.c auth2-gss.c] [auth2-hostbased.c auth2-kbdint.c auth2-none.c auth2-passwd.c ] [auth2-pubkey.c auth2.c authfd.c authfd.h authfile.c bufaux.c bufbn.c] [buffer.c buffer.h canohost.c channels.c channels.h cipher-3des1.c] [cipher-bf1.c cipher-ctr.c cipher.c cleanup.c clientloop.c compat.c] [compress.c deattack.c dh.c dispatch.c dns.c dns.h fatal.c groupaccess.c] [groupaccess.h gss-genr.c gss-serv-krb5.c gss-serv.c hostfile.c kex.c] [kex.h kexdh.c kexdhc.c kexdhs.c kexgex.c kexgexc.c kexgexs.c key.c] [key.h log.c log.h mac.c match.c md-sha256.c misc.c misc.h moduli.c] [monitor.c monitor_fdpass.c monitor_mm.c monitor_mm.h monitor_wrap.c] [monitor_wrap.h msg.c nchan.c packet.c progressmeter.c readconf.c] [readconf.h readpass.c rsa.c scard.c scard.h scp.c servconf.c servconf.h] [serverloop.c session.c session.h sftp-client.c sftp-common.c] [sftp-common.h sftp-glob.c sftp-server.c sftp.c ssh-add.c ssh-agent.c] [ssh-dss.c ssh-gss.h ssh-keygen.c ssh-keyscan.c ssh-keysign.c ssh-rsa.c] [ssh.c ssh.h sshconnect.c sshconnect.h sshconnect1.c sshconnect2.c] [sshd.c sshlogin.c sshlogin.h sshpty.c sshpty.h sshtty.c ttymodes.c] [uidswap.c uidswap.h uuencode.c uuencode.h xmalloc.c xmalloc.h] [loginrec.c loginrec.h openbsd-compat/port-aix.c openbsd-compat/port-tun.h] almost entirely get rid of the culture of ".h files that include .h files" ok djm, sort of ok stevesk makes the pain stop in one easy step NB. portable commit contains everything *except* removing includes.h, as that will take a fair bit more work as we move headers that are required for portability workarounds to defines.h. (also, this step wasn't "easy")
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#include <sys/types.h>
#include <limits.h>
- deraadt@cvs.openbsd.org 2006/08/03 03:34:42 [OVERVIEW atomicio.c atomicio.h auth-bsdauth.c auth-chall.c auth-krb5.c] [auth-options.c auth-options.h auth-passwd.c auth-rh-rsa.c auth-rhosts.c] [auth-rsa.c auth-skey.c auth.c auth.h auth1.c auth2-chall.c auth2-gss.c] [auth2-hostbased.c auth2-kbdint.c auth2-none.c auth2-passwd.c ] [auth2-pubkey.c auth2.c authfd.c authfd.h authfile.c bufaux.c bufbn.c] [buffer.c buffer.h canohost.c channels.c channels.h cipher-3des1.c] [cipher-bf1.c cipher-ctr.c cipher.c cleanup.c clientloop.c compat.c] [compress.c deattack.c dh.c dispatch.c dns.c dns.h fatal.c groupaccess.c] [groupaccess.h gss-genr.c gss-serv-krb5.c gss-serv.c hostfile.c kex.c] [kex.h kexdh.c kexdhc.c kexdhs.c kexgex.c kexgexc.c kexgexs.c key.c] [key.h log.c log.h mac.c match.c md-sha256.c misc.c misc.h moduli.c] [monitor.c monitor_fdpass.c monitor_mm.c monitor_mm.h monitor_wrap.c] [monitor_wrap.h msg.c nchan.c packet.c progressmeter.c readconf.c] [readconf.h readpass.c rsa.c scard.c scard.h scp.c servconf.c servconf.h] [serverloop.c session.c session.h sftp-client.c sftp-common.c] [sftp-common.h sftp-glob.c sftp-server.c sftp.c ssh-add.c ssh-agent.c] [ssh-dss.c ssh-gss.h ssh-keygen.c ssh-keyscan.c ssh-keysign.c ssh-rsa.c] [ssh.c ssh.h sshconnect.c sshconnect.h sshconnect1.c sshconnect2.c] [sshd.c sshlogin.c sshlogin.h sshpty.c sshpty.h sshtty.c ttymodes.c] [uidswap.c uidswap.h uuencode.c uuencode.h xmalloc.c xmalloc.h] [loginrec.c loginrec.h openbsd-compat/port-aix.c openbsd-compat/port-tun.h] almost entirely get rid of the culture of ".h files that include .h files" ok djm, sort of ok stevesk makes the pain stop in one easy step NB. portable commit contains everything *except* removing includes.h, as that will take a fair bit more work as we move headers that are required for portability workarounds to defines.h. (also, this step wasn't "easy")
2006-08-05 04:39:39 +02:00
#include <stdarg.h>
#include <string.h>
#include <signal.h>
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#include <stdlib.h>
#include <unistd.h>
#include "xmalloc.h"
#include "ssherr.h"
#include "sshbuf.h"
#include "log.h"
#include "ssh2.h"
#include "ssh-gss.h"
/* sshbuf_get for gss_buffer_desc */
int
ssh_gssapi_get_buffer_desc(struct sshbuf *b, gss_buffer_desc *g)
{
int r;
u_char *p;
size_t len;
if ((r = sshbuf_get_string(b, &p, &len)) != 0)
return r;
g->value = p;
g->length = len;
return 0;
}
/* 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)
{
return (ctx != NULL && ctx->oid != GSS_C_NO_OID &&
ctx->oid->length == len &&
memcmp(ctx->oid->elements, data, len) == 0);
}
/* Set the contexts OID from a data stream */
void
ssh_gssapi_set_oid_data(Gssctxt *ctx, void *data, size_t len)
{
if (ctx->oid != GSS_C_NO_OID) {
free(ctx->oid->elements);
free(ctx->oid);
}
ctx->oid = xcalloc(1, sizeof(gss_OID_desc));
ctx->oid->length = len;
ctx->oid->elements = xmalloc(len);
memcpy(ctx->oid->elements, data, len);
}
/* Set the contexts OID */
void
ssh_gssapi_set_oid(Gssctxt *ctx, gss_OID oid)
{
ssh_gssapi_set_oid_data(ctx, oid->elements, oid->length);
}
/* All this effort to report an error ... */
void
ssh_gssapi_error(Gssctxt *ctxt)
{
char *s;
s = ssh_gssapi_last_error(ctxt, NULL, NULL);
debug("%s", s);
free(s);
}
char *
ssh_gssapi_last_error(Gssctxt *ctxt, OM_uint32 *major_status,
OM_uint32 *minor_status)
{
OM_uint32 lmin;
gss_buffer_desc msg = GSS_C_EMPTY_BUFFER;
OM_uint32 ctx;
struct sshbuf *b;
char *ret;
int r;
if ((b = sshbuf_new()) == NULL)
fatal_f("sshbuf_new failed");
if (major_status != NULL)
*major_status = ctxt->major;
if (minor_status != NULL)
*minor_status = ctxt->minor;
ctx = 0;
/* The GSSAPI error */
do {
gss_display_status(&lmin, ctxt->major,
GSS_C_GSS_CODE, ctxt->oid, &ctx, &msg);
if ((r = sshbuf_put(b, msg.value, msg.length)) != 0 ||
(r = sshbuf_put_u8(b, '\n')) != 0)
fatal_fr(r, "assemble GSS_CODE");
gss_release_buffer(&lmin, &msg);
} while (ctx != 0);
/* The mechanism specific error */
do {
gss_display_status(&lmin, ctxt->minor,
GSS_C_MECH_CODE, ctxt->oid, &ctx, &msg);
if ((r = sshbuf_put(b, msg.value, msg.length)) != 0 ||
(r = sshbuf_put_u8(b, '\n')) != 0)
fatal_fr(r, "assemble MECH_CODE");
gss_release_buffer(&lmin, &msg);
} while (ctx != 0);
if ((r = sshbuf_put_u8(b, '\n')) != 0)
fatal_fr(r, "assemble newline");
ret = xstrdup((const char *)sshbuf_ptr(b));
sshbuf_free(b);
return (ret);
}
/*
* Initialise our GSSAPI context. We use this opaque structure to contain all
* of the data which both the client and server need to persist across
* {accept,init}_sec_context calls, so that when we do it from the userauth
* stuff life is a little easier
*/
void
ssh_gssapi_build_ctx(Gssctxt **ctx)
{
*ctx = xcalloc(1, sizeof (Gssctxt));
(*ctx)->context = GSS_C_NO_CONTEXT;
(*ctx)->name = GSS_C_NO_NAME;
(*ctx)->oid = GSS_C_NO_OID;
(*ctx)->creds = GSS_C_NO_CREDENTIAL;
(*ctx)->client = GSS_C_NO_NAME;
(*ctx)->client_creds = GSS_C_NO_CREDENTIAL;
}
/* Delete our context, providing it has been built correctly */
void
ssh_gssapi_delete_ctx(Gssctxt **ctx)
{
OM_uint32 ms;
if ((*ctx) == NULL)
return;
if ((*ctx)->context != GSS_C_NO_CONTEXT)
gss_delete_sec_context(&ms, &(*ctx)->context, GSS_C_NO_BUFFER);
if ((*ctx)->name != GSS_C_NO_NAME)
gss_release_name(&ms, &(*ctx)->name);
if ((*ctx)->oid != GSS_C_NO_OID) {
free((*ctx)->oid->elements);
free((*ctx)->oid);
(*ctx)->oid = GSS_C_NO_OID;
}
if ((*ctx)->creds != GSS_C_NO_CREDENTIAL)
gss_release_cred(&ms, &(*ctx)->creds);
if ((*ctx)->client != GSS_C_NO_NAME)
gss_release_name(&ms, &(*ctx)->client);
if ((*ctx)->client_creds != GSS_C_NO_CREDENTIAL)
gss_release_cred(&ms, &(*ctx)->client_creds);
free(*ctx);
*ctx = NULL;
}
/*
* Wrapper to init_sec_context
* Requires that the context contains:
* oid
* server name (from ssh_gssapi_import_name)
*/
OM_uint32
ssh_gssapi_init_ctx(Gssctxt *ctx, int deleg_creds, gss_buffer_desc *recv_tok,
gss_buffer_desc* send_tok, OM_uint32 *flags)
{
int deleg_flag = 0;
if (deleg_creds) {
deleg_flag = GSS_C_DELEG_FLAG;
debug("Delegating credentials");
}
ctx->major = gss_init_sec_context(&ctx->minor,
GSS_C_NO_CREDENTIAL, &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);
if (GSS_ERROR(ctx->major))
ssh_gssapi_error(ctx);
return (ctx->major);
}
/* Create a service name for the given host */
OM_uint32
ssh_gssapi_import_name(Gssctxt *ctx, const char *host)
{
gss_buffer_desc gssbuf;
char *val;
xasprintf(&val, "host@%s", host);
gssbuf.value = val;
gssbuf.length = strlen(gssbuf.value);
if ((ctx->major = gss_import_name(&ctx->minor,
&gssbuf, GSS_C_NT_HOSTBASED_SERVICE, &ctx->name)))
ssh_gssapi_error(ctx);
free(gssbuf.value);
return (ctx->major);
}
OM_uint32
ssh_gssapi_sign(Gssctxt *ctx, gss_buffer_t buffer, gss_buffer_t hash)
{
if ((ctx->major = gss_get_mic(&ctx->minor, ctx->context,
GSS_C_QOP_DEFAULT, buffer, hash)))
ssh_gssapi_error(ctx);
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return (ctx->major);
}
void
ssh_gssapi_buildmic(struct sshbuf *b, const char *user, const char *service,
const char *context, const struct sshbuf *session_id)
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{
int r;
sshbuf_reset(b);
if ((r = sshbuf_put_stringb(b, session_id)) != 0 ||
(r = sshbuf_put_u8(b, SSH2_MSG_USERAUTH_REQUEST)) != 0 ||
(r = sshbuf_put_cstring(b, user)) != 0 ||
(r = sshbuf_put_cstring(b, service)) != 0 ||
(r = sshbuf_put_cstring(b, context)) != 0)
fatal_fr(r, "assemble buildmic");
}
int
ssh_gssapi_check_mechanism(Gssctxt **ctx, gss_OID oid, const char *host)
{
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"};
/* RFC 4462 says we MUST NOT do SPNEGO */
if (oid->length == spnego_oid.length &&
(memcmp(oid->elements, spnego_oid.elements, oid->length) == 0))
return 0; /* false */
ssh_gssapi_build_ctx(ctx);
ssh_gssapi_set_oid(*ctx, oid);
major = ssh_gssapi_import_name(*ctx, host);
if (!GSS_ERROR(major)) {
major = ssh_gssapi_init_ctx(*ctx, 0, GSS_C_NO_BUFFER, &token,
NULL);
gss_release_buffer(&minor, &token);
if ((*ctx)->context != GSS_C_NO_CONTEXT)
gss_delete_sec_context(&minor, &(*ctx)->context,
GSS_C_NO_BUFFER);
}
if (GSS_ERROR(major))
ssh_gssapi_delete_ctx(ctx);
return (!GSS_ERROR(major));
}
#endif /* GSSAPI */