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PAM support, the FreeBSD way.

Browse Source 
Sponsored by:	DARPA, NAI Labs
This commit is contained in:
Dag-Erling Smørgrav 2002-06-29 10:56:23 +00:00
parent 1f334c7bc7
commit 382d19ee61
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=99052
6 changed files with 588 additions and 10 deletions
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20
crypto/openssh/auth2-chall.c
View File

@ -24,6 +24,7 @@
*/
#include "includes.h"
RCSID("$OpenBSD: auth2-chall.c,v 1.18 2002/06/19 00:27:55 deraadt Exp $");
RCSID("$FreeBSD$");
#include "ssh2.h"
#include "auth.h"
@ -41,6 +42,9 @@ static void input_userauth_info_response(int, u_int32_t, void *);
#ifdef BSD_AUTH
extern KbdintDevice bsdauth_device;
#else
#ifdef USE_PAM
extern KbdintDevice pam_device;
#endif
#ifdef SKEY
extern KbdintDevice skey_device;
#endif
@ -50,6 +54,9 @@ KbdintDevice *devices[] = {
#ifdef BSD_AUTH
&bsdauth_device,
#else
#ifdef USE_PAM
&pam_device,
#endif
#ifdef SKEY
&skey_device,
#endif
@ -317,15 +324,22 @@ privsep_challenge_enable(void)
#ifdef BSD_AUTH
extern KbdintDevice mm_bsdauth_device;
#endif
#ifdef USE_PAM
extern KbdintDevice mm_pam_device;
#endif
#ifdef SKEY
extern KbdintDevice mm_skey_device;
#endif
/* As long as SSHv1 has devices[0] hard coded this is fine */
int n = 0;
#ifdef BSD_AUTH
devices[0] = &mm_bsdauth_device;
devices[n++] = &mm_bsdauth_device;
#else
#ifdef USE_PAM
devices[n++] = &mm_pam_device;
#endif
#ifdef SKEY
devices[0] = &mm_skey_device;
devices[n++] = &mm_skey_device;
#endif
#endif
}

372
crypto/openssh/auth2-pam-freebsd.c Normal file
View File

@ -0,0 +1,372 @@
/*-
* Copyright (c) 2002 Networks Associates Technology, Inc.
* All rights reserved.
*
* This software was developed for the FreeBSD Project by ThinkSec AS and
* NAI Labs, the Security Research Division of Network Associates, Inc.
* under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the
* DARPA CHATS research program.
*
* 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.
* 3. The name of the author may not be used to endorse or promote
* products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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"
RCSID("$FreeBSD$");
#ifdef USE_PAM
#include <security/pam_appl.h>
#include "auth.h"
#include "log.h"
#include "monitor_wrap.h"
#include "packet.h"
#include "ssh2.h"
#include "xmalloc.h"
struct pam_ctxt {
char *pam_user;
pid_t pam_pid;
int pam_sock;
int pam_done;
};
static void pam_free_ctx(void *);
/*
* Send message to parent or child.
*/
static int
pam_send(struct pam_ctxt *ctxt, char *fmt, ...)
{
va_list ap;
char *mstr;
size_t len;
int r;
va_start(ap, fmt);
len = vasprintf(&mstr, fmt, ap);
va_end(ap);
if (mstr == NULL)
exit(1);
if (ctxt->pam_pid != 0)
debug2("to child: %s", mstr);
r = send(ctxt->pam_sock, mstr, len + 1, MSG_EOR);
free(mstr);
return (r);
}
/*
* Peek at first byte of next message.
*/
static int
pam_peek(struct pam_ctxt *ctxt)
{
char ch;
if (recv(ctxt->pam_sock, &ch, 1, MSG_PEEK) < 1)
return (-1);
return (ch);
}
/*
* Receive a message from parent or child.
*/
static char *
pam_receive(struct pam_ctxt *ctxt)
{
char *buf;
size_t len;
ssize_t rlen;
len = 64;
buf = NULL;
do {
len *= 2;
buf = xrealloc(buf, len);
rlen = recv(ctxt->pam_sock, buf, len, MSG_PEEK);
if (rlen < 1) {
xfree(buf);
return (NULL);
}
} while (rlen == len);
if (recv(ctxt->pam_sock, buf, len, 0) != rlen) {
xfree(buf);
return (NULL);
}
if (ctxt->pam_pid != 0)
debug2("from child: %s", buf);
return (buf);
}
/*
* Conversation function for child process.
*/
static int
pam_child_conv(int n,
const struct pam_message **msg,
struct pam_response **resp,
void *data)
{
struct pam_ctxt *ctxt;
int i;
ctxt = data;
if (n <= 0 || n > PAM_MAX_NUM_MSG)
return (PAM_CONV_ERR);
if ((*resp = calloc(n, sizeof **resp)) == NULL)
return (PAM_BUF_ERR);
for (i = 0; i < n; ++i) {
resp[i]->resp_retcode = 0;
resp[i]->resp = NULL;
switch (msg[i]->msg_style) {
case PAM_PROMPT_ECHO_OFF:
pam_send(ctxt, "p%s", msg[i]->msg);
resp[i]->resp = pam_receive(ctxt);
break;
case PAM_PROMPT_ECHO_ON:
pam_send(ctxt, "P%s", msg[i]->msg);
resp[i]->resp = pam_receive(ctxt);
break;
case PAM_ERROR_MSG:
pam_send(ctxt, "e%s", msg[i]->msg);
break;
case PAM_TEXT_INFO:
pam_send(ctxt, "i%s", msg[i]->msg);
break;
default:
goto fail;
}
}
return (PAM_SUCCESS);
fail:
while (i)
free(resp[--i]);
free(*resp);
*resp = NULL;
return (PAM_CONV_ERR);
}
/*
* Child process.
*/
static void *
pam_child(struct pam_ctxt *ctxt)
{
struct pam_conv pam_conv = { pam_child_conv, ctxt };
pam_handle_t *pamh;
int pam_err;
pam_err = pam_start("sshd", ctxt->pam_user, &pam_conv, &pamh);
if (pam_err != PAM_SUCCESS)
goto auth_fail;
pam_err = pam_authenticate(pamh, 0);
if (pam_err != PAM_SUCCESS)
goto auth_fail;
pam_err = pam_acct_mgmt(pamh, 0);
if (pam_err != PAM_SUCCESS)
goto auth_fail;
pam_send(ctxt, "=OK");
pam_end(pamh, pam_err);
exit(0);
auth_fail:
pam_send(ctxt, "!%s", pam_strerror(pamh, pam_err));
pam_end(pamh, pam_err);
exit(0);
}
static void *
pam_init_ctx(Authctxt *authctxt)
{
struct pam_ctxt *ctxt;
int socks[2];
int i;
ctxt = xmalloc(sizeof *ctxt);
ctxt->pam_user = xstrdup(authctxt->user);
ctxt->pam_done = 0;
if (socketpair(AF_UNIX, SOCK_DGRAM, PF_UNSPEC, socks) == -1) {
error("%s: failed create sockets: %s",
__func__, strerror(errno));
xfree(ctxt);
return (NULL);
}
if ((ctxt->pam_pid = fork()) == -1) {
error("%s: failed to fork auth-pam child: %s",
__func__, strerror(errno));
close(socks[0]);
close(socks[1]);
xfree(ctxt);
return (NULL);
}
if (ctxt->pam_pid == 0) {
/* close everything except our end of the pipe */
ctxt->pam_sock = socks[1];
for (i = 0; i < getdtablesize(); ++i)
if (i != ctxt->pam_sock)
close(i);
pam_child(ctxt);
/* not reached */
exit(1);
}
ctxt->pam_sock = socks[0];
close(socks[1]);
return (ctxt);
}
static int
pam_query(void *ctx, char **name, char **info,
u_int *num, char ***prompts, u_int **echo_on)
{
struct pam_ctxt *ctxt = ctx;
size_t plen;
char *msg;
*name = xstrdup("");
*info = xstrdup("");
*prompts = xmalloc(sizeof(char *));
**prompts = NULL;
plen = 0;
*echo_on = xmalloc(sizeof(u_int));
while ((msg = pam_receive(ctxt)) != NULL) {
switch (*msg) {
case 'P':
case 'p':
*num = 1;
**prompts = xrealloc(**prompts, plen + strlen(msg));
plen += sprintf(**prompts + plen, "%s", msg + 1);
**echo_on = (*msg == 'P');
xfree(msg);
return (0);
case 'e':
case 'i':
/* accumulate messages */
**prompts = xrealloc(**prompts, plen + strlen(msg));
plen += sprintf(**prompts + plen, "%s", msg + 1);
break;
case '=':
case '!':
if (**prompts != NULL) {
/* drain any accumulated messages */
#if 0 /* not compatible with privsep */
packet_start(SSH2_MSG_USERAUTH_BANNER);
packet_put_cstring(**prompts);
packet_put_cstring("");
packet_send();
packet_write_wait();
#endif
xfree(**prompts);
**prompts = NULL;
}
if (*msg == '=') {
*num = 0;
**echo_on = 0;
ctxt->pam_done = 1;
xfree(msg);
return (0);
}
error("%s", msg + 1);
default:
*num = 0;
**echo_on = 0;
xfree(msg);
ctxt->pam_done = -1;
return (-1);
}
xfree(msg);
}
return (-1);
}
static int
pam_respond(void *ctx, u_int num, char **resp)
{
struct pam_ctxt *ctxt = ctx;
char *msg;
debug2(__func__);
switch (ctxt->pam_done) {
case 1:
return (0);
case 0:
break;
default:
return (-1);
}
if (num != 1) {
error("expected one response, got %u", num);
return (-1);
}
pam_send(ctxt, "%s", *resp);
switch (pam_peek(ctxt)) {
case 'P':
case 'p':
case 'e':
case 'i':
return (1);
case '=':
msg = pam_receive(ctxt);
xfree(msg);
ctxt->pam_done = 1;
return (0);
default:
msg = pam_receive(ctxt);
if (*msg == '!')
error("%s", msg + 1);
xfree(msg);
ctxt->pam_done = -1;
return (-1);
}
}
static void
pam_free_ctx(void *ctxtp)
{
struct pam_ctxt *ctxt = ctxtp;
int status;
close(ctxt->pam_sock);
kill(ctxt->pam_pid, SIGHUP);
waitpid(ctxt->pam_pid, &status, 0);
xfree(ctxt->pam_user);
xfree(ctxt);
}
KbdintDevice pam_device = {
"pam",
pam_init_ctx,
pam_query,
pam_respond,
pam_free_ctx
};
KbdintDevice mm_pam_device = {
"pam",
mm_pam_init_ctx,
mm_pam_query,
mm_pam_respond,
mm_pam_free_ctx
};
#endif /* USE_PAM */

113
crypto/openssh/monitor.c
View File

@ -127,6 +127,10 @@ int mm_answer_sessid(int, Buffer *);
#ifdef USE_PAM
int mm_answer_pam_start(int, Buffer *);
int mm_answer_pam_init_ctx(int, Buffer *);
int mm_answer_pam_query(int, Buffer *);
int mm_answer_pam_respond(int, Buffer *);
int mm_answer_pam_free_ctx(int, Buffer *);
#endif
static Authctxt *authctxt;
@ -165,6 +169,10 @@ struct mon_table mon_dispatch_proto20[] = {
{MONITOR_REQ_AUTHPASSWORD, MON_AUTH, mm_answer_authpassword},
#ifdef USE_PAM
{MONITOR_REQ_PAM_START, MON_ONCE, mm_answer_pam_start},
{MONITOR_REQ_PAM_INIT_CTX, MON_ISAUTH, mm_answer_pam_init_ctx},
{MONITOR_REQ_PAM_QUERY, MON_ISAUTH, mm_answer_pam_query},
{MONITOR_REQ_PAM_RESPOND, MON_ISAUTH, mm_answer_pam_respond},
{MONITOR_REQ_PAM_FREE_CTX, MON_ONCE|MON_AUTHDECIDE, mm_answer_pam_free_ctx},
#endif
#ifdef BSD_AUTH
{MONITOR_REQ_BSDAUTHQUERY, MON_ISAUTH, mm_answer_bsdauthquery},
@ -199,6 +207,10 @@ struct mon_table mon_dispatch_proto15[] = {
{MONITOR_REQ_RSARESPONSE, MON_ONCE|MON_AUTHDECIDE, mm_answer_rsa_response},
#ifdef USE_PAM
{MONITOR_REQ_PAM_START, MON_ONCE, mm_answer_pam_start},
{MONITOR_REQ_PAM_INIT_CTX, MON_ISAUTH, mm_answer_pam_init_ctx},
{MONITOR_REQ_PAM_QUERY, MON_ISAUTH, mm_answer_pam_query},
{MONITOR_REQ_PAM_RESPOND, MON_ISAUTH, mm_answer_pam_respond},
{MONITOR_REQ_PAM_FREE_CTX, MON_ONCE|MON_AUTHDECIDE, mm_answer_pam_free_ctx},
#endif
#ifdef BSD_AUTH
{MONITOR_REQ_BSDAUTHQUERY, MON_ISAUTH, mm_answer_bsdauthquery},
@ -207,9 +219,6 @@ struct mon_table mon_dispatch_proto15[] = {
#ifdef SKEY
{MONITOR_REQ_SKEYQUERY, MON_ISAUTH, mm_answer_skeyquery},
{MONITOR_REQ_SKEYRESPOND, MON_AUTH, mm_answer_skeyrespond},
#endif
#ifdef USE_PAM
{MONITOR_REQ_PAM_START, MON_ONCE, mm_answer_pam_start},
#endif
{0, 0, NULL}
};
@ -284,10 +293,6 @@ monitor_child_preauth(struct monitor *pmonitor)
if (authctxt->pw->pw_uid == 0 &&
!auth_root_allowed(auth_method))
authenticated = 0;
#ifdef USE_PAM
if (!do_pam_account(authctxt->pw->pw_name, NULL))
authenticated = 0;
#endif
}
if (ent->flags & MON_AUTHDECIDE) {
@ -745,6 +750,100 @@ mm_answer_pam_start(int socket, Buffer *m)
return (0);
}
static void *pam_ctxt, *pam_authok;
extern KbdintDevice pam_device;
int
mm_answer_pam_init_ctx(int socket, Buffer *m)
{
debug3("%s", __func__);
authctxt->user = buffer_get_string(m, NULL);
pam_ctxt = (pam_device.init_ctx)(authctxt);
pam_authok = NULL;
buffer_clear(m);
if (pam_ctxt != NULL) {
monitor_permit(mon_dispatch, MONITOR_REQ_PAM_FREE_CTX, 1);
buffer_put_int(m, 1);
} else {
buffer_put_int(m, 0);
}
mm_request_send(socket, MONITOR_ANS_PAM_INIT_CTX, m);
return (0);
}
int
mm_answer_pam_query(int socket, Buffer *m)
{
char *name, *info, **prompts;
u_int num, *echo_on;
int i, ret;
debug3("%s", __func__);
pam_authok = NULL;
ret = (pam_device.query)(pam_ctxt, &name, &info, &num, &prompts, &echo_on);
if (num > 1 || name == NULL || info == NULL)
ret = -1;
buffer_put_int(m, ret);
buffer_put_cstring(m, name);
xfree(name);
buffer_put_cstring(m, info);
xfree(info);
buffer_put_int(m, num);
for (i = 0; i < num; ++i) {
buffer_put_cstring(m, prompts[i]);
xfree(prompts[i]);
buffer_put_int(m, echo_on[i]);
}
if (prompts != NULL)
xfree(prompts);
if (echo_on != NULL)
xfree(echo_on);
mm_request_send(socket, MONITOR_ANS_PAM_QUERY, m);
return (0);
}
int
mm_answer_pam_respond(int socket, Buffer *m)
{
char **resp;
u_int num;
int i, ret;
debug3("%s", __func__);
pam_authok = NULL;
num = buffer_get_int(m);
if (num > 0) {
resp = xmalloc(num * sizeof(char *));
for (i = 0; i < num; ++i)
resp[i] = buffer_get_string(m, NULL);
ret = (pam_device.respond)(pam_ctxt, num, resp);
for (i = 0; i < num; ++i)
xfree(resp[i]);
xfree(resp);
} else {
ret = (pam_device.respond)(pam_ctxt, num, NULL);
}
buffer_clear(m);
buffer_put_int(m, ret);
mm_request_send(socket, MONITOR_ANS_PAM_RESPOND, m);
auth_method = "keyboard-interactive/pam";
if (ret == 0)
pam_authok = pam_ctxt;
return (ret);
}
int
mm_answer_pam_free_ctx(int socket, Buffer *m)
{
debug3("%s", __func__);
(pam_device.free_ctx)(pam_ctxt);
buffer_clear(m);
mm_request_send(socket, MONITOR_ANS_PAM_FREE_CTX, m);
return (pam_authok == pam_ctxt);
}
#endif
static void

5
crypto/openssh/monitor.h
View File

@ -1,4 +1,5 @@
/* $OpenBSD: monitor.h,v 1.6 2002/06/11 05:46:20 mpech Exp $ */
/* $FreeBSD$ */
/*
* Copyright 2002 Niels Provos <provos@citi.umich.edu>
@ -50,6 +51,10 @@ enum monitor_reqtype {
MONITOR_REQ_RSACHALLENGE, MONITOR_ANS_RSACHALLENGE,
MONITOR_REQ_RSARESPONSE, MONITOR_ANS_RSARESPONSE,
MONITOR_REQ_PAM_START,
MONITOR_REQ_PAM_INIT_CTX, MONITOR_ANS_PAM_INIT_CTX,
MONITOR_REQ_PAM_QUERY, MONITOR_ANS_PAM_QUERY,
MONITOR_REQ_PAM_RESPOND, MONITOR_ANS_PAM_RESPOND,
MONITOR_REQ_PAM_FREE_CTX, MONITOR_ANS_PAM_FREE_CTX,
MONITOR_REQ_TERM
};

83
crypto/openssh/monitor_wrap.c
View File

@ -26,6 +26,7 @@
#include "includes.h"
RCSID("$OpenBSD: monitor_wrap.c,v 1.11 2002/06/19 18:01:00 markus Exp $");
RCSID("$FreeBSD$");
#include <openssl/bn.h>
#include <openssl/dh.h>
@ -664,6 +665,88 @@ mm_start_pam(char *user)
buffer_free(&m);
}
void *
mm_pam_init_ctx(Authctxt *authctxt)
{
Buffer m;
int success;
debug3("%s", __func__);
buffer_init(&m);
buffer_put_cstring(&m, authctxt->user);
mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_PAM_INIT_CTX, &m);
debug3("%s: waiting for MONITOR_ANS_PAM_INIT_CTX", __func__);
mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_PAM_INIT_CTX, &m);
success = buffer_get_int(&m);
if (success == 0) {
debug3("%s: pam_init_ctx failed", __func__);
buffer_free(&m);
return (NULL);
}
buffer_free(&m);
return (authctxt);
}
int
mm_pam_query(void *ctx, char **name, char **info,
u_int *num, char ***prompts, u_int **echo_on)
{
Buffer m;
int i, ret;
debug3("%s", __func__);
buffer_init(&m);
mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_PAM_QUERY, &m);
debug3("%s: waiting for MONITOR_ANS_PAM_QUERY", __func__);
mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_PAM_QUERY, &m);
ret = buffer_get_int(&m);
debug3("%s: pam_query returned %d", __func__, ret);
*name = buffer_get_string(&m, NULL);
*info = buffer_get_string(&m, NULL);
*num = buffer_get_int(&m);
*prompts = xmalloc((*num + 1) * sizeof(char *));
*echo_on = xmalloc((*num + 1) * sizeof(u_int));
for (i = 0; i < *num; ++i) {
(*prompts)[i] = buffer_get_string(&m, NULL);
(*echo_on)[i] = buffer_get_int(&m);
}
buffer_free(&m);
return (ret);
}
int
mm_pam_respond(void *ctx, u_int num, char **resp)
{
Buffer m;
int i, ret;
debug3("%s", __func__);
buffer_init(&m);
buffer_put_int(&m, num);
for (i = 0; i < num; ++i)
buffer_put_cstring(&m, resp[i]);
mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_PAM_RESPOND, &m);
debug3("%s: waiting for MONITOR_ANS_PAM_RESPOND", __func__);
mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_PAM_RESPOND, &m);
ret = buffer_get_int(&m);
debug3("%s: pam_respond returned %d", __func__, ret);
buffer_free(&m);
return (ret);
}
void
mm_pam_free_ctx(void *ctxtp)
{
Buffer m;
debug3("%s", __func__);
buffer_init(&m);
mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_PAM_FREE_CTX, &m);
debug3("%s: waiting for MONITOR_ANS_PAM_FREE_CTX", __func__);
mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_PAM_FREE_CTX, &m);
buffer_free(&m);
}
#endif /* USE_PAM */
/* Request process termination */

5
crypto/openssh/monitor_wrap.h
View File

@ -1,4 +1,5 @@
/* $OpenBSD: monitor_wrap.h,v 1.5 2002/05/12 23:53:45 djm Exp $ */
/* $FreeBSD$ */
/*
* Copyright 2002 Niels Provos <provos@citi.umich.edu>
@ -57,6 +58,10 @@ BIGNUM *mm_auth_rsa_generate_challenge(Key *);
#ifdef USE_PAM
void mm_start_pam(char *);
void *mm_pam_init_ctx(struct Authctxt *);
int mm_pam_query(void *, char **, char **, u_int *, char ***, u_int **);
int mm_pam_respond(void *, u_int, char **);
void mm_pam_free_ctx(void *);
#endif
void mm_terminate(void);