freebsd-skq/crypto/openssh/auth2-pam-freebsd.c
des ac9c3868c1 Rewrite to use the buffer API instead of roll-your-own messaging.
Suggested by:	Markus Friedl <markus@openbsd.org>
Sponsored by:	DARPA, NAI Labs
2002-07-05 15:27:26 +00:00

322 lines
7.8 KiB
C

/*-
* 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 "buffer.h"
#include "bufaux.h"
#include "log.h"
#include "monitor_wrap.h"
#include "msg.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 *);
/*
* Conversation function for child process.
*/
static int
pam_child_conv(int n,
const struct pam_message **msg,
struct pam_response **resp,
void *data)
{
Buffer buffer;
struct pam_ctxt *ctxt;
int i;
ctxt = data;
if (n <= 0 || n > PAM_MAX_NUM_MSG)
return (PAM_CONV_ERR);
*resp = xmalloc(n * sizeof **resp);
buffer_init(&buffer);
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:
buffer_put_cstring(&buffer, msg[i]->msg);
msg_send(ctxt->pam_sock, msg[i]->msg_style, &buffer);
msg_recv(ctxt->pam_sock, &buffer);
if (buffer_get_char(&buffer) != PAM_AUTHTOK)
goto fail;
resp[i]->resp = buffer_get_string(&buffer, NULL);
break;
case PAM_PROMPT_ECHO_ON:
buffer_put_cstring(&buffer, msg[i]->msg);
msg_send(ctxt->pam_sock, msg[i]->msg_style, &buffer);
msg_recv(ctxt->pam_sock, &buffer);
if (buffer_get_char(&buffer) != PAM_AUTHTOK)
goto fail;
resp[i]->resp = buffer_get_string(&buffer, NULL);
break;
case PAM_ERROR_MSG:
buffer_put_cstring(&buffer, msg[i]->msg);
msg_send(ctxt->pam_sock, msg[i]->msg_style, &buffer);
break;
case PAM_TEXT_INFO:
buffer_put_cstring(&buffer, msg[i]->msg);
msg_send(ctxt->pam_sock, msg[i]->msg_style, &buffer);
break;
default:
goto fail;
}
buffer_clear(&buffer);
}
buffer_free(&buffer);
return (PAM_SUCCESS);
fail:
while (i)
xfree(resp[--i]);
xfree(*resp);
*resp = NULL;
buffer_free(&buffer);
return (PAM_CONV_ERR);
}
/*
* Child process.
*/
static void *
pam_child(struct pam_ctxt *ctxt)
{
Buffer buffer;
struct pam_conv pam_conv = { pam_child_conv, ctxt };
pam_handle_t *pamh;
int pam_err;
buffer_init(&buffer);
setproctitle("%s [pam]", ctxt->pam_user);
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;
buffer_put_cstring(&buffer, "OK");
msg_send(ctxt->pam_sock, PAM_SUCCESS, &buffer);
buffer_free(&buffer);
pam_end(pamh, pam_err);
exit(0);
auth_fail:
buffer_put_cstring(&buffer, pam_strerror(pamh, pam_err));
msg_send(ctxt->pam_sock, PAM_AUTH_ERR, &buffer);
buffer_free(&buffer);
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_STREAM, 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 = 3; 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)
{
Buffer buffer;
struct pam_ctxt *ctxt = ctx;
size_t plen;
u_char type;
char *msg;
buffer_init(&buffer);
*name = xstrdup("");
*info = xstrdup("");
*prompts = xmalloc(sizeof(char *));
**prompts = NULL;
plen = 0;
*echo_on = xmalloc(sizeof(u_int));
while (msg_recv(ctxt->pam_sock, &buffer) == 0) {
type = buffer_get_char(&buffer);
msg = buffer_get_string(&buffer, NULL);
switch (type) {
case PAM_PROMPT_ECHO_ON:
case PAM_PROMPT_ECHO_OFF:
*num = 1;
**prompts = xrealloc(**prompts, plen + strlen(msg) + 1);
plen += sprintf(**prompts + plen, "%s", msg);
**echo_on = (type == PAM_PROMPT_ECHO_ON);
xfree(msg);
return (0);
case PAM_ERROR_MSG:
case PAM_TEXT_INFO:
/* accumulate messages */
**prompts = xrealloc(**prompts, plen + strlen(msg) + 1);
plen += sprintf(**prompts + plen, "%s", msg);
xfree(msg);
break;
case PAM_SUCCESS:
case PAM_AUTH_ERR:
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 (type == PAM_SUCCESS) {
*num = 0;
**echo_on = 0;
ctxt->pam_done = 1;
xfree(msg);
return (0);
}
error("%s", msg);
default:
*num = 0;
**echo_on = 0;
xfree(msg);
ctxt->pam_done = -1;
return (-1);
}
}
return (-1);
}
static int
pam_respond(void *ctx, u_int num, char **resp)
{
Buffer buffer;
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);
}
buffer_init(&buffer);
buffer_put_cstring(&buffer, *resp);
msg_send(ctxt->pam_sock, PAM_AUTHTOK, &buffer);
buffer_free(&buffer);
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 */