335 lines
7.0 KiB
C
335 lines
7.0 KiB
C
/*-
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* Copyright (c) 2002 Networks Associates Technology, Inc.
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* All rights reserved.
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*
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* This software was developed for the FreeBSD Project by ThinkSec AS and
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* NAI Labs, the Security Research Division of Network Associates, Inc.
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* under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the
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* DARPA CHATS research program.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote
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* products derived from this software without specific prior written
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* permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#ifdef USE_PAM
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#include "includes.h"
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RCSID("$FreeBSD$");
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#include <security/pam_appl.h>
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#include "auth.h"
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#include "xmalloc.h"
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struct pam_ctxt {
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char *pam_user;
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pid_t pam_pid;
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int pam_sock;
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int pam_done;
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};
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static void pam_free_ctx(void *);
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/*
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* Send message to parent or child.
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*/
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static int
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pam_send(struct pam_ctxt *ctxt, char *fmt, ...)
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{
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va_list ap;
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char *mstr;
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size_t len;
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int r;
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va_start(ap, fmt);
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len = vasprintf(&mstr, fmt, ap);
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va_end(ap);
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if (mstr == NULL)
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exit(1);
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if (ctxt->pam_pid != 0)
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debug2("to child: %s", mstr);
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r = send(ctxt->pam_sock, mstr, len + 1, MSG_EOR);
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free(mstr);
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return (r);
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}
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/*
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* Peek at first byte of next message.
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*/
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static int
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pam_peek(struct pam_ctxt *ctxt)
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{
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char ch;
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if (recv(ctxt->pam_sock, &ch, 1, MSG_PEEK) < 1)
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return (-1);
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return (ch);
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}
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/*
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* Receive a message from parent or child.
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*/
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static char *
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pam_receive(struct pam_ctxt *ctxt)
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{
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char *buf;
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size_t len;
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ssize_t rlen;
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len = 64;
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buf = NULL;
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do {
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len *= 2;
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buf = xrealloc(buf, len);
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rlen = recv(ctxt->pam_sock, buf, len, MSG_PEEK);
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if (rlen < 1) {
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xfree(buf);
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return (NULL);
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}
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} while (rlen == len);
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if (recv(ctxt->pam_sock, buf, len, 0) != rlen) {
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xfree(buf);
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return (NULL);
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}
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if (ctxt->pam_pid != 0)
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debug2("from child: %s", buf);
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return (buf);
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}
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/*
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* Conversation function for child process.
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*/
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static int
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pam_child_conv(int n,
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const struct pam_message **msg,
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struct pam_response **resp,
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void *data)
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{
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struct pam_ctxt *ctxt;
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char *line;
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size_t len;
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int i;
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ctxt = data;
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if (n <= 0 || n > PAM_MAX_NUM_MSG)
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return (PAM_CONV_ERR);
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if ((*resp = calloc(n, sizeof **resp)) == NULL)
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return (PAM_BUF_ERR);
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for (i = 0; i < n; ++i) {
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resp[i]->resp_retcode = 0;
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resp[i]->resp = NULL;
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switch (msg[i]->msg_style) {
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case PAM_PROMPT_ECHO_OFF:
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pam_send(ctxt, "p%s", msg[i]->msg);
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resp[i]->resp = pam_receive(ctxt);
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break;
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case PAM_PROMPT_ECHO_ON:
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pam_send(ctxt, "P%s", msg[i]->msg);
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resp[i]->resp = pam_receive(ctxt);
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break;
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case PAM_ERROR_MSG:
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/*pam_send(ctxt, "e%s", msg[i]->msg);*/
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break;
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case PAM_TEXT_INFO:
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/*pam_send(ctxt, "i%s", msg[i]->msg);*/
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break;
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default:
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goto fail;
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}
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}
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return (PAM_SUCCESS);
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fail:
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while (i)
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free(resp[--i]);
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free(*resp);
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*resp = NULL;
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return (PAM_CONV_ERR);
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}
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/*
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* Child process.
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*/
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static void *
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pam_child(struct pam_ctxt *ctxt)
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{
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struct pam_conv pam_conv = { pam_child_conv, ctxt };
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pam_handle_t *pamh;
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char *msg;
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int pam_err;
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pam_err = pam_start("sshd", ctxt->pam_user, &pam_conv, &pamh);
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if (pam_err != PAM_SUCCESS)
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goto auth_fail;
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pam_err = pam_authenticate(pamh, 0);
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if (pam_err != PAM_SUCCESS)
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goto auth_fail;
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pam_send(ctxt, "=OK");
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pam_end(pamh, pam_err);
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exit(0);
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auth_fail:
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pam_send(ctxt, "!%s", pam_strerror(pamh, pam_err));
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pam_end(pamh, pam_err);
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exit(0);
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}
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static void *
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pam_init_ctx(Authctxt *authctxt)
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{
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struct pam_ctxt *ctxt;
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int socks[2];
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int i;
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ctxt = xmalloc(sizeof *ctxt);
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ctxt->pam_user = xstrdup(authctxt->user);
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ctxt->pam_done = 0;
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if (socketpair(AF_UNIX, SOCK_DGRAM, PF_UNSPEC, socks) == -1) {
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error("%s: failed create sockets: %s",
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__func__, strerror(errno));
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xfree(ctxt);
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return (NULL);
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}
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if ((ctxt->pam_pid = fork()) == -1) {
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error("%s: failed to fork auth-pam child: %s",
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__func__, strerror(errno));
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close(socks[0]);
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close(socks[1]);
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xfree(ctxt);
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return (NULL);
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}
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if (ctxt->pam_pid == 0) {
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/* close everything except our end of the pipe */
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ctxt->pam_sock = socks[1];
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for (i = 0; i < getdtablesize(); ++i)
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if (i != ctxt->pam_sock)
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close(i);
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pam_child(ctxt);
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/* not reached */
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exit(1);
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}
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ctxt->pam_sock = socks[0];
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close(socks[1]);
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return (ctxt);
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}
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static int
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pam_query(void *ctx, char **name, char **info,
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u_int *num, char ***prompts, u_int **echo_on)
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{
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struct pam_ctxt *ctxt = ctx;
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char *msg;
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if ((msg = pam_receive(ctxt)) == NULL)
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return (-1);
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*name = xstrdup("");
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*info = xstrdup("");
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*prompts = xmalloc(sizeof(char *));
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*echo_on = xmalloc(sizeof(u_int));
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switch (*msg) {
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case 'P':
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**echo_on = 1;
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case 'p':
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*num = 1;
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**prompts = xstrdup(msg + 1);
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**echo_on = (*msg == 'P');
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break;
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case '=':
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*num = 0;
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**echo_on = 0;
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ctxt->pam_done = 1;
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break;
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case '!':
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error("%s", msg + 1);
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default:
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*num = 0;
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**echo_on = 0;
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xfree(msg);
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ctxt->pam_done = -1;
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return (-1);
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}
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xfree(msg);
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return (0);
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}
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static int
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pam_respond(void *ctx, u_int num, char **resp)
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{
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struct pam_ctxt *ctxt = ctx;
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char *msg;
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debug2(__func__);
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switch (ctxt->pam_done) {
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case 1:
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return (0);
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case 0:
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break;
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default:
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return (-1);
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}
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if (num != 1) {
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error("expected one response, got %u", num);
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return (-1);
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}
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pam_send(ctxt, "%s", *resp);
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switch (pam_peek(ctxt)) {
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case 'P':
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case 'p':
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return (1);
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case '=':
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msg = pam_receive(ctxt);
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xfree(msg);
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ctxt->pam_done = 1;
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return (0);
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default:
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msg = pam_receive(ctxt);
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if (*msg == '!')
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error("%s", msg + 1);
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xfree(msg);
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ctxt->pam_done = -1;
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return (-1);
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}
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}
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static void
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pam_free_ctx(void *ctxtp)
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{
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struct pam_ctxt *ctxt = ctxtp;
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int i;
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close(ctxt->pam_sock);
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kill(ctxt->pam_pid, SIGHUP);
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xfree(ctxt->pam_user);
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xfree(ctxt);
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}
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KbdintDevice pam_device = {
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"pam",
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pam_init_ctx,
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pam_query,
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pam_respond,
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pam_free_ctx
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};
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#endif /* USE_PAM */
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