path: root/camel/camel-sasl-cram-md5.c

/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
/*
 *  Authors: Jeffrey Stedfast <fejj@ximian.com>
 *
 *  Copyright 2001 Ximian, Inc. (www.ximian.com)
 *
 *  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 Street #330, Boston, MA 02111-1307, USA.
 *
 */

#include <config.h>
#include "camel-sasl-cram-md5.h"
#include <e-util/md5-utils.h>
#include <stdio.h>
#include <string.h>

static CamelSaslClass *parent_class = NULL;

/* Returns the class for a CamelSaslCramMd5 */
#define CSCM_CLASS(so) CAMEL_SASL_CRAM_MD5_CLASS (CAMEL_OBJECT_GET_CLASS (so))

static GByteArray *cram_md5_challenge (CamelSasl *sasl, const char *token, CamelException *ex);

enum {
    STATE_AUTH,
    STATE_FINAL
};

struct _CamelSaslCramMd5Private {
    int state;
};

static void
camel_sasl_cram_md5_class_init (CamelSaslCramMd5Class *camel_sasl_cram_md5_class)
{
    CamelSaslClass *camel_sasl_class = CAMEL_SASL_CLASS (camel_sasl_cram_md5_class);
    
    parent_class = CAMEL_SASL_CLASS (camel_type_get_global_classfuncs (camel_sasl_get_type ()));
    
    /* virtual method overload */
    camel_sasl_class->challenge = cram_md5_challenge;
}

static void
camel_sasl_cram_md5_init (gpointer object, gpointer klass)
{
    CamelSaslCramMd5 *sasl_cram = CAMEL_SASL_CRAM_MD5 (object);
    
    sasl_cram->priv = g_new0 (struct _CamelSaslCramMd5Private, 1);
}

static void
camel_sasl_cram_md5_finalize (CamelObject *object)
{
    CamelSaslCramMd5 *sasl = CAMEL_SASL_CRAM_MD5 (object);
    
    g_free (sasl->username);
    g_free (sasl->priv);
}


CamelType
camel_sasl_cram_md5_get_type (void)
{
    static CamelType type = CAMEL_INVALID_TYPE;
    
    if (type == CAMEL_INVALID_TYPE) {
        type = camel_type_register (camel_sasl_get_type (),
                        "CamelSaslCramMd5",
                        sizeof (CamelSaslCramMd5),
                        sizeof (CamelSaslCramMd5Class),
                        (CamelObjectClassInitFunc) camel_sasl_cram_md5_class_init,
                        NULL,
                        (CamelObjectInitFunc) camel_sasl_cram_md5_init,
                        (CamelObjectFinalizeFunc) camel_sasl_cram_md5_finalize);
    }
    
    return type;
}

CamelSasl *
camel_sasl_cram_md5_new (const char *username, const char *passwd)
{
    CamelSaslCramMd5 *sasl_cram;
    
    if (!username) return NULL;
    if (!passwd) return NULL;
    
    sasl_cram = CAMEL_SASL_CRAM_MD5 (camel_object_new (camel_sasl_cram_md5_get_type ()));
    sasl_cram->username = g_strdup (username);
    sasl_cram->passwd = g_strdup (passwd);
    
    return CAMEL_SASL (sasl_cram);
}

/* CRAM-MD5 algorithm:
 * MD5 ((passwd XOR opad), MD5 ((passwd XOR ipad), timestamp))
 */

static GByteArray *
cram_md5_challenge (CamelSasl *sasl, const char *token, CamelException *ex)
{
    CamelSaslCramMd5 *sasl_cram = CAMEL_SASL_CRAM_MD5 (sasl);
    struct _CamelSaslCramMd5Private *priv = sasl_cram->priv;
    guchar digest[16], md5asc[33], *s, *p;
    char *timestamp, *passwd;
    GByteArray *ret = NULL;
    guchar ipad[64];
    guchar opad[64];
    MD5Context ctx;
    int i, pw_len;
    
    switch (priv->state) {
    case STATE_AUTH:
        timestamp = (char *) token;
        
        passwd = sasl_cram->passwd;
        pw_len = strlen (sasl_cram->passwd);
        if (pw_len > 64) {
            md5_init (&ctx);
            md5_update (&ctx, passwd, pw_len);
            md5_final (&ctx, digest);
            passwd = g_strdup (digest);
            pw_len = 16;
        }
        
        memset (ipad, 0, sizeof (ipad));
        memset (opad, 0, sizeof (opad));
        memcpy (ipad, passwd, pw_len);
        memcpy (opad, passwd, pw_len);
        
        for (i = 0; i < 64; i++) {
            ipad[i] ^= 0x36;
            opad[i] ^= 0x5c;
        }
        
        md5_init (&ctx);
        md5_update (&ctx, ipad, 64);
        md5_update (&ctx, timestamp, strlen (timestamp));
        md5_final (&ctx, digest);
        
        md5_init (&ctx);
        md5_update (&ctx, opad, 64);
        md5_update (&ctx, digest, 16);
        md5_final (&ctx, digest);
        
        /* lowercase hexify that bad-boy... */
        for (s = digest, p = md5asc; p < md5asc + 32; s++, p += 2)
            sprintf (p, "%.2x", *s);
        
        ret = g_byte_array_new ();
        g_byte_array_append (ret, sasl_cram->username, strlen (sasl_cram->username));
        g_byte_array_append (ret, " ", 1);
        g_byte_array_append (ret, md5asc, strlen (md5asc));
        
        break;
    case STATE_FINAL:
        sasl->authenticated = TRUE;
    default:
        break;
    }
    
    priv->state++;
    
    return ret;
}