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added CRAM-MD5 authentication support.

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parse server capability string to determine if STARTTLS is available
This commit is contained in:
Michael Elkins 2000-12-23 00:02:42 +00:00
parent 074298d482
commit b3eb5661eb
5 changed files with 161 additions and 10 deletions
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2
Makefile.am
View file

@ -1,5 +1,5 @@
bin_PROGRAMS=isync
isync_SOURCES=main.c imap.c sync.c maildir.c isync.h list.c
isync_SOURCES=main.c imap.c sync.c maildir.c isync.h list.c cram.c
man_MANS=isync.1
EXTRA_DIST=sample.isyncrc $(man_MANS)
CPPFLAGS=$(RPM_OPT_FLAGS)

3
README
View file

@ -18,8 +18,9 @@ maintained, and all flags are synchronized.
* Fast mode for fetching new mail only
* Supports imaps: (port 993) TLS/SSL connections
* Supports STARTTLS (RFC2595)
* Supports STARTTLS (RFC2595) for confidentiality
* Supports NAMESPACE (RFC2342)
* Supports CRAM-MD5 (RFC2095) for authentication
* Compatibility

85
cram.c Normal file
View file

@ -0,0 +1,85 @@
/* $Id$
*
* isync - IMAP4 to maildir mailbox synchronizer
* Copyright (C) 2000 Michael R. Elkins <me@mutt.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <assert.h>
#include "isync.h"
#if HAVE_LIBSSL
#include <openssl/hmac.h>
#define ENCODED_SIZE(n) (4*((n+2)/3))
static char
hexchar (unsigned int b)
{
if (b < 10)
return '0' + b;
return 'a' + (b - 10);
}
char *
cram (const char *challenge, const char *user, const char *pass)
{
HMAC_CTX hmac;
char hash[16];
char hex[33];
int i;
unsigned int hashlen = sizeof (hash);
char buf[256];
int len = strlen (challenge);
char *response = calloc (1, 1 + len);
char *final;
/* response will always be smaller than challenge because we are
* decoding.
*/
len = EVP_DecodeBlock ((unsigned char *) response, (unsigned char *) challenge, strlen (challenge));
// printf ("CRAM-MD5 challege is %s\n", response);
HMAC_Init (&hmac, (unsigned char *) pass, strlen (pass), EVP_md5 ());
HMAC_Update (&hmac, (unsigned char *) response, strlen(response));
HMAC_Final (&hmac, (unsigned char *) hash, &hashlen);
assert (hashlen == sizeof (hash));
free (response);
hex[32] = 0;
for (i = 0; i < 16; i++)
{
hex[2 * i] = hexchar ((hash[i] >> 4) & 0xf);
hex[2 * i + 1] = hexchar (hash[i] & 0xf);
}
snprintf (buf, sizeof (buf), "%s %s", user, hex);
// printf ("Response: %s\n", buf);
len = strlen (buf);
len = ENCODED_SIZE (len) + 1;
final = malloc (len);
final[len - 1] = 0;
assert (EVP_EncodeBlock ((unsigned char *) final, (unsigned char *) buf, strlen (buf)) == len - 1);
return final;
}
#endif

74
imap.c
View file

@ -401,6 +401,18 @@ imap_exec (imap_t * imap, const char *fmt, ...)
{
parse_response_code (imap, cmd);
}
else if (!strcmp ("CAPABILITY", arg))
{
#if HAVE_LIBSSL
while ((arg = next_arg (&cmd)))
{
if (!strcmp ("STARTTLS", arg))
imap->have_starttls = 1;
else if (!strcmp ("AUTH=CRAM-MD5", arg))
imap->have_cram = 1;
}
#endif
}
else if ((arg1 = next_arg (&cmd)))
{
if (!strcmp ("EXISTS", arg1))
@ -428,6 +440,26 @@ imap_exec (imap_t * imap, const char *fmt, ...)
return -1;
}
}
#if HAVE_LIBSSL
else if (*arg == '+')
{
char *resp;
if (!imap->cram)
{
puts ("Error, not doing CRAM-MD5 authentication");
return -1;
}
resp = cram (cmd, imap->box->user, imap->box->pass);
socket_write (imap->sock, resp, strlen (resp));
if (Verbose)
puts (resp);
socket_write (imap->sock, "\r\n", 2);
free (resp);
imap->cram = 0;
}
#endif
else if ((size_t) atol (arg) != Tag)
{
puts ("wrong tag");
@ -510,17 +542,23 @@ imap_open (config_t * box, unsigned int minuid)
#if HAVE_LIBSSL
if (!box->use_imaps)
{
/* let's see what this puppy can do... */
ret = imap_exec (imap, "CAPABILITY");
/* always try to select SSL support if available */
ret = imap_exec (imap, "STARTTLS");
if (!ret)
if (imap->have_starttls && !imap_exec (imap, "STARTTLS"))
use_ssl = 1;
else if (box->require_ssl)
if (!use_ssl)
{
puts ("Error, SSL support not available");
return 0;
if (box->require_ssl)
{
puts ("Error, SSL support not available");
return 0;
}
else
puts ("Warning, SSL support not available");
}
else
puts ("Warning, SSL support not available");
}
else
use_ssl = 1;
@ -543,11 +581,31 @@ imap_open (config_t * box, unsigned int minuid)
imap->sock->use_ssl = 1;
puts ("SSL support enabled");
if (box->use_imaps)
ret = imap_exec (imap, "CAPABILITY");
}
#else
ret = imap_exec (imap, "CAPABILITY");
#endif
puts ("Logging in...");
ret = imap_exec (imap, "LOGIN \"%s\" \"%s\"", box->user, box->pass);
#if HAVE_LIBSSL
if (imap->have_cram)
{
puts ("Authenticating with CRAM-MD5");
imap->cram = 1;
ret = imap_exec (imap, "AUTHENTICATE CRAM-MD5");
}
else
#endif
{
#if HAVE_LIBSSL
if (!use_ssl)
#endif
puts ("*** Warning *** Password is being sent in the clear");
ret = imap_exec (imap, "LOGIN \"%s\" \"%s\"", box->user, box->pass);
}
if (!ret)
{

7
isync.h
View file

@ -130,6 +130,11 @@ typedef struct
list_t *ns_personal;
list_t *ns_other;
list_t *ns_shared;
#if HAVE_LIBSSL
unsigned int have_cram:1;
unsigned int have_starttls:1;
unsigned int cram:1;
#endif
}
imap_t;
@ -144,6 +149,8 @@ extern int Verbose;
#if HAVE_LIBSSL
extern SSL_CTX *SSLContext;
char *cram (const char *, const char *, const char *);
#endif
char *next_arg (char **);