/* MODULE: auth_rimap */
/* COPYRIGHT
* Copyright (c) 1998 Messaging Direct Ltd.
* 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 MESSAGING DIRECT LTD. ``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 MESSAGING DIRECT LTD. OR
* ITS EMPLOYEES OR AGENTS 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.
*
* Copyright 1998, 1999 Carnegie Mellon University
*
* All Rights Reserved
*
* Permission to use, copy, modify, and distribute this software and its
* documentation for any purpose and without fee is hereby granted,
* provided that the above copyright notice appear in all copies and that
* both that copyright notice and this permission notice appear in
* supporting documentation, and that the name of Carnegie Mellon
* University not be used in advertising or publicity pertaining to
* distribution of the software without specific, written prior
* permission.
*
* CARNEGIE MELLON UNIVERSITY DISCLAIMS ALL WARRANTIES WITH REGARD TO
* THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
* FITNESS, IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY BE LIABLE FOR
* ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
* OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
* END COPYRIGHT */
/* SYNOPSIS
* Proxy authentication to a remote IMAP (or IMSP) server.
* END SYNOPSIS */
#ifdef __GNUC__
#ident "$Id: auth_rimap.c,v 1.14 2011/09/22 14:39:03 mel Exp $"
#endif
/* PUBLIC DEPENDENCIES */
#include "mechanisms.h"
#include <unistd.h>
#include <stdlib.h>
#include <assert.h>
#include <errno.h>
#include <string.h>
#ifdef _AIX
# include <strings.h>
#endif /* _AIX */
#include <syslog.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <signal.h>
#include <netdb.h>
#include "auth_rimap.h"
#include "utils.h"
#include "globals.h"
/* END PUBLIC DEPENDENCIES */
/* PRIVATE DEPENDENCIES */
static const char *r_host = NULL; /* remote hostname (mech_option) */
static struct addrinfo *ai = NULL; /* remote authentication host */
/* END PRIVATE DEPENDENCIES */
#define DEFAULT_REMOTE_SERVICE "imap" /* getservbyname() name for remote
service we connect to. */
#define TAG "saslauthd" /* IMAP command tag */
#define LOGIN_CMD (TAG " LOGIN ") /* IMAP login command (with tag) */
#define NETWORK_IO_TIMEOUT 30 /* network I/O timeout (seconds) */
#define RESP_LEN 1000 /* size of read response buffer */
/* Common failure response strings for auth_rimap() */
#define RESP_IERROR "NO [ALERT] saslauthd internal error"
#define RESP_UNAVAILABLE "NO [ALERT] The remote authentication server is currently unavailable"
#define RESP_UNEXPECTED "NO [ALERT] Unexpected response from remote authentication server"
/* FUNCTION: sig_null */
/* SYNOPSIS
* Catch and ignore a signal.
* END SYNOPSIS */
static RETSIGTYPE /* R: OS dependent */
sig_null (
/* PARAMETERS */
int sig /* I: signal being caught */
/* END PARAMETERS */
)
{
switch (sig) {
case SIGALRM:
signal(SIGALRM, sig_null);
break;
case SIGPIPE:
signal(SIGPIPE, sig_null);
break;
default:
syslog(LOG_WARNING, "auth_rimap: unexpected signal %d", sig);
break;
}
#ifdef __APPLE__
return;
#else /* __APPLE__ */
# if RETSIGTYPE == void
return;
# else /* RETSIGTYPE */
return 0;
# endif /* RETSIGTYPE */
#endif /* __APPLE__ */
}
/* END FUNCTION: sig_null */
/* FUNCTION: qstring */
/* SYNOPSIS
* Quote a string for transmission over the IMAP protocol.
* END SYNOPSIS */
static char * /* R: the quoted string */
qstring (
/* PARAMETERS */
const char *s /* I: string to quote */
/* END PARAMETERS */
)
{
char *c; /* pointer to returned string */
register const char *p1; /* scratch pointers */
register char *p2; /* scratch pointers */
int len; /* length of array to malloc */
int num_quotes; /* number of '"' chars in string*/
/* see of we have to deal with any '"' characters */
num_quotes = 0;
p1 = s;
while ((p1 = strchr(p1, '"')) != NULL) {
p1++;
num_quotes++;
}
if (!num_quotes) {
/*
* no double-quotes to escape, so just wrap the input string
* in double-quotes and return it.
*/
len = strlen(s) + 2 + 1;
c = malloc(len);
if (c == NULL) {
return NULL;
}
*c = '"';
*(c+1) = '\0';
strcat(c, s);
strcat(c, "\"");
return c;
}
/*
* Ugh, we have to escape double quotes ...
*/
len = strlen(s) + 2 + (2*num_quotes) + 1;
c = malloc(len);
if (c == NULL) {
return NULL;
}
p1 = s;
p2 = c;
*p2++ = '"';
while (*p1) {
if (*p1 == '"') {
*p2++ = '\\'; /* escape the '"' */
}
*p2++ = *p1++;
}
strcpy(p2, "\"");
return c;
}
/* END FUNCTION: qstring */
/* FUNCTION: auth_rimap_init */
/* SYNOPSIS
* Validate the host and service names for the remote server.
* END SYNOPSIS */
int
auth_rimap_init (
/* PARAMETERS */
void /* no parameters */
/* END PARAMETERS */
)
{
/* VARIABLES */
struct addrinfo hints;
int err;
char *c; /* scratch pointer */
/* END VARIABLES */
if (mech_option == NULL) {
syslog(LOG_ERR, "rimap_init: no hostname specified");
return -1;
} else {
r_host = mech_option;
}
/* Determine the port number to connect to.
*
* r_host has already been initialized to the hostname and optional port
* port name to connect to. The format of the string is:
*
* hostname
* or
* hostname/port
*/
c = strchr(r_host, '/'); /* look for optional service */
if (c != NULL) {
*c++ = '\0'; /* tie off hostname and point */
/* to service string */
} else {
c = DEFAULT_REMOTE_SERVICE;
}
if (ai)
freeaddrinfo(ai);
memset(&hints, 0, sizeof(hints));
hints.ai_family = PF_UNSPEC;
hints.ai_socktype = SOCK_STREAM;
hints.ai_flags = AI_CANONNAME;
if ((err = getaddrinfo(r_host, c, &hints, &ai)) != 0) {
syslog(LOG_ERR, "auth_rimap_init: getaddrinfo %s/%s: %s",
r_host, c, gai_strerror(err));
return -1;
}
/* Make sure we have AF_INET or AF_INET6 addresses. */
if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) {
syslog(LOG_ERR, "auth_rimap_init: no IP address info for %s",
ai->ai_canonname ? ai->ai_canonname : r_host);
freeaddrinfo(ai);
ai = NULL;
return -1;
}
return 0;
}
/* END FUNCTION: auth_rimap_init */
/* FUNCTION: auth_rimap */
/* SYNOPSIS
* Proxy authenticate to a remote IMAP server.
*
* This mechanism takes the plaintext authenticator and password, forms
* them into an IMAP LOGIN command, then attempts to authenticate to
* a remote IMAP server using those values. If the remote authentication
* succeeds the credentials are considered valid.
*
* NOTE: since IMSP uses the same form of LOGIN command as IMAP does,
* this driver will also work with IMSP servers.
*/
/* XXX This should be extended to support SASL PLAIN authentication */
char * /* R: Allocated response string */
auth_rimap (
/* PARAMETERS */
const char *login, /* I: plaintext authenticator */
const char *password, /* I: plaintext password */
const char *service __attribute__((unused)),
const char *realm __attribute__((unused))
/* END PARAMETERS */
)
{
/* VARIABLES */
int s=-1; /* socket to remote auth host */
struct addrinfo *r; /* remote socket address info */
struct iovec iov[5]; /* for sending LOGIN command */
char *qlogin; /* pointer to "quoted" login */
char *qpass; /* pointer to "quoted" password */
char *c; /* scratch pointer */
int rc; /* return code scratch area */
char rbuf[RESP_LEN]; /* response read buffer */
char hbuf[NI_MAXHOST], pbuf[NI_MAXSERV];
int saved_errno;
int niflags;
/* END VARIABLES */
/* sanity checks */
assert(login != NULL);
assert(password != NULL);
/*establish connection to remote */
for (r = ai; r; r = r->ai_next) {
s = socket(r->ai_family, r->ai_socktype, r->ai_protocol);
if (s < 0)
continue;
if (connect(s, r->ai_addr, r->ai_addrlen) >= 0)
break;
close(s);
s = -1;
saved_errno = errno;
niflags = (NI_NUMERICHOST | NI_NUMERICSERV);
#ifdef NI_WITHSCOPEID
if (r->ai_family == AF_INET6)
niflags |= NI_WITHSCOPEID;
#endif
if (getnameinfo(r->ai_addr, r->ai_addrlen, hbuf, sizeof(hbuf),
pbuf, sizeof(pbuf), niflags) != 0) {
strlcpy(hbuf, "unknown", sizeof(hbuf));
strlcpy(pbuf, "unknown", sizeof(pbuf));
}
errno = saved_errno;
syslog(LOG_WARNING, "auth_rimap: connect %s[%s]/%s: %m",
ai->ai_canonname ? ai->ai_canonname : r_host, hbuf, pbuf);
}
if (s < 0) {
if (getnameinfo(ai->ai_addr, ai->ai_addrlen, NULL, 0,
pbuf, sizeof(pbuf), NI_NUMERICSERV) != 0)
strlcpy(pbuf, "unknown", sizeof(pbuf));
syslog(LOG_WARNING, "auth_rimap: couldn't connect to %s/%s",
ai->ai_canonname ? ai->ai_canonname : r_host, pbuf);
return strdup("NO [ALERT] Couldn't contact remote authentication server");
}
/* CLAIM: we now have a TCP connection to the remote IMAP server */
/*
* Install noop signal handlers. These just reinstall the handler
* and return so that we take an EINTR during network I/O.
*/
(void) signal(SIGALRM, sig_null);
(void) signal(SIGPIPE, sig_null);
/* read and parse the IMAP banner */
alarm(NETWORK_IO_TIMEOUT);
rc = read(s, rbuf, sizeof(rbuf));
alarm(0);
if ( rc>0 ) {
/* check if there is more to read */
fd_set perm;
int fds, ret;
struct timeval timeout;
FD_ZERO(&perm);
FD_SET(s, &perm);
fds = s +1;
timeout.tv_sec = 1;
timeout.tv_usec = 0;
while( select (fds, &perm, NULL, NULL, &timeout ) >0 ) {
if ( FD_ISSET(s, &perm) ) {
ret = read(s, rbuf+rc, sizeof(rbuf)-rc);
if ( ret<0 ) {
rc = ret;
break;
} else {
rc += ret;
}
}
}
}
if (rc == -1) {
syslog(LOG_WARNING, "auth_rimap: read (banner): %m");
(void) close(s);
return strdup("NO [ALERT] error synchronizing with remote authentication server");
}
rbuf[rc] = '\0'; /* tie off response */
c = strpbrk(rbuf, "\r\n");
if (c != NULL) {
*c = '\0'; /* tie off line termination */
}
if (!strncmp(rbuf, "* NO", sizeof("* NO")-1)) {
(void) close(s);
return strdup(RESP_UNAVAILABLE);
}
if (!strncmp(rbuf, "* BYE", sizeof("* BYE")-1)) {
(void) close(s);
return strdup(RESP_UNAVAILABLE);
}
if (strncmp(rbuf, "* OK", sizeof("* OK")-1)) {
syslog(LOG_WARNING,
"auth_rimap: unexpected response during initial handshake: %s",
rbuf);
(void) close(s);
return strdup(RESP_UNEXPECTED);
}
/* build the LOGIN command */
qlogin = qstring(login); /* quote login */
qpass = qstring(password); /* quote password */
if (qlogin == NULL) {
if (qpass != NULL) {
memset(qpass, 0, strlen(qpass));
free(qpass);
}
(void) close(s);
syslog(LOG_WARNING, "auth_rimap: qstring(login) == NULL");
return strdup(RESP_IERROR);
}
if (qpass == NULL) {
if (qlogin != NULL) {
memset(qlogin, 0, strlen(qlogin));
free(qlogin);
}
(void) close(s);
syslog(LOG_WARNING, "auth_rimap: qstring(password) == NULL");
return strdup(RESP_IERROR);
}
iov[0].iov_base = LOGIN_CMD;
iov[0].iov_len = sizeof(LOGIN_CMD) - 1;
iov[1].iov_base = qlogin;
iov[1].iov_len = strlen(qlogin);
iov[2].iov_base = " ";
iov[2].iov_len = sizeof(" ") - 1;
iov[3].iov_base = qpass;
iov[3].iov_len = strlen(qpass);
iov[4].iov_base = "\r\n";
iov[4].iov_len = sizeof("\r\n") - 1;
if (flags & VERBOSE) {
syslog(LOG_DEBUG, "auth_rimap: sending %s%s %s",
LOGIN_CMD, qlogin, qpass);
}
alarm(NETWORK_IO_TIMEOUT);
rc = retry_writev(s, iov, 5);
alarm(0);
if (rc == -1) {
syslog(LOG_WARNING, "auth_rimap: writev: %m");
memset(qlogin, 0, strlen(qlogin));
free(qlogin);
memset(qpass, 0, strlen(qpass));
free(qpass);
(void)close(s);
return strdup(RESP_IERROR);
}
/* don't need these any longer */
memset(qlogin, 0, strlen(qlogin));
free(qlogin);
memset(qpass, 0, strlen(qpass));
free(qpass);
/* read and parse the LOGIN response */
alarm(NETWORK_IO_TIMEOUT);
rc = read(s, rbuf, sizeof(rbuf));
alarm(0);
if ( rc>0 ) {
/* check if there is more to read */
fd_set perm;
int fds, ret;
struct timeval timeout;
FD_ZERO(&perm);
FD_SET(s, &perm);
fds = s +1;
timeout.tv_sec = 1;
timeout.tv_usec = 0;
while( select (fds, &perm, NULL, NULL, &timeout ) >0 ) {
if ( FD_ISSET(s, &perm) ) {
ret = read(s, rbuf+rc, sizeof(rbuf)-rc);
if ( ret<0 ) {
rc = ret;
break;
} else {
rc += ret;
}
}
}
}
(void) close(s); /* we're done with the remote */
if (rc == -1) {
syslog(LOG_WARNING, "auth_rimap: read (response): %m");
return strdup(RESP_IERROR);
}
rbuf[rc] = '\0'; /* tie off response */
c = strpbrk(rbuf, "\r\n");
if (c != NULL) {
*c = '\0'; /* tie off line termination */
}
if (!strncmp(rbuf, TAG " OK", sizeof(TAG " OK")-1)) {
if (flags & VERBOSE) {
syslog(LOG_DEBUG, "auth_rimap: [%s] %s", login, rbuf);
}
return strdup("OK remote authentication successful");
}
if (!strncmp(rbuf, TAG " NO", sizeof(TAG " NO")-1)) {
if (flags & VERBOSE) {
syslog(LOG_DEBUG, "auth_rimap: [%s] %s", login, rbuf);
}
return strdup("NO remote server rejected your credentials");
}
syslog(LOG_WARNING, "auth_rimap: unexpected response to auth request: %s",
rbuf);
return strdup(RESP_UNEXPECTED);
}
/* END FUNCTION: auth_rimap */
/* END MODULE: auth_rimap */