path: root/mail/mail-crypto.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 <stdlib.h>
#include <string.h>

#include "mail-crypto.h"
#include "mail-session.h"

#include <camel/camel-mime-filter-from.h>

/** rfc2015 stuff (aka PGP/MIME) *******************************/

gboolean
mail_crypto_is_rfc2015_signed (CamelMimePart *mime_part)
{
    CamelDataWrapper *wrapper;
    CamelMultipart *mp;
    CamelMimePart *part;
    CamelContentType *type;
    const gchar *param, *micalg;
    int nparts;
    
    /* check that we have a multipart/signed */
    type = camel_mime_part_get_content_type (mime_part);
    if (!header_content_type_is (type, "multipart", "signed"))
        return FALSE;
    
    /* check that we have a protocol param with the value: "application/pgp-signed" */
    param = header_content_type_param (type, "protocol");
    if (!param || g_strcasecmp (param, "application/pgp-signature"))
        return FALSE;
    
    /* check that we have a micalg parameter */
    micalg = header_content_type_param (type, "micalg");
    if (!micalg)
        return FALSE;
    
    /* check that we have exactly 2 subparts */
    wrapper = camel_medium_get_content_object (CAMEL_MEDIUM (mime_part));
    mp = CAMEL_MULTIPART (wrapper);
    nparts = camel_multipart_get_number (mp);
    if (nparts != 2)
        return FALSE;
    
    /* The first part may be of any type except for 
     * application/pgp-signature - check it. */
    part = camel_multipart_get_part (mp, 0);
    type = camel_mime_part_get_content_type (part);
    if (header_content_type_is (type, "application", "pgp-signature"))
        return FALSE;
    
    /* The second part should be application/pgp-signature. */
    part = camel_multipart_get_part (mp, 1);
    type = camel_mime_part_get_content_type (part);
    if (!header_content_type_is (type, "application", "pgp-signature"))
        return FALSE;
    
    return TRUE;
}

gboolean
mail_crypto_is_rfc2015_encrypted (CamelMimePart *mime_part)
{
    CamelDataWrapper *wrapper;
    CamelMultipart *mp;
    CamelMimePart *part;
    CamelContentType *type;
    const gchar *param;
    int nparts;
    
    /* check that we have a multipart/encrypted */
    type = camel_mime_part_get_content_type (mime_part);
    if (!header_content_type_is (type, "multipart", "encrypted"))
        return FALSE;
    
    /* check that we have a protocol param with the value: "application/pgp-encrypted" */
    param = header_content_type_param (type, "protocol");
    if (!param || g_strcasecmp (param, "application/pgp-encrypted"))
        return FALSE;
    
    /* check that we have at least 2 subparts */
    wrapper = camel_medium_get_content_object (CAMEL_MEDIUM (mime_part));
    mp = CAMEL_MULTIPART (wrapper);
    nparts = camel_multipart_get_number (mp);
    if (nparts < 2)
        return FALSE;
    
    /* The first part should be application/pgp-encrypted */
    part = camel_multipart_get_part (mp, 0);
    type = camel_mime_part_get_content_type (part);
    if (!header_content_type_is (type, "application", "pgp-encrypted"))
        return FALSE;
    
    /* The second part should be application/octet-stream - this
           is the one we care most about */
    part = camel_multipart_get_part (mp, 1);
    type = camel_mime_part_get_content_type (part);
    if (!header_content_type_is (type, "application", "octet-stream"))
        return FALSE;
    
    return TRUE;
}


/** rfc2633 stuff (aka S/MIME v3) ********************************/

gboolean
mail_crypto_is_smime_v3_signed (CamelMimePart *mime_part)
{
    CamelDataWrapper *wrapper;
    CamelMultipart *mp;
    CamelMimePart *part;
    CamelContentType *type;
    const gchar *param, *micalg;
    int nparts;
    
    /* check that we have a multipart/signed */
    type = camel_mime_part_get_content_type (mime_part);
    if (!header_content_type_is (type, "multipart", "signed"))
        return FALSE;
    
    /* check that we have a protocol param with the value: "application/pgp-signed" */
    param = header_content_type_param (type, "protocol");
    if (!param || g_strcasecmp (param, "application/pkcs7-signature"))
        return FALSE;
    
    /* check that we have a micalg parameter */
    micalg = header_content_type_param (type, "micalg");
    if (!micalg)
        return FALSE;
    
    /* check that we have exactly 2 subparts */
    wrapper = camel_medium_get_content_object (CAMEL_MEDIUM (mime_part));
    mp = CAMEL_MULTIPART (wrapper);
    nparts = camel_multipart_get_number (mp);
    if (nparts != 2)
        return FALSE;
    
    /* The first part may be of any type except for 
     * application/pkcs7-signature - check it. */
    part = camel_multipart_get_part (mp, 0);
    type = camel_mime_part_get_content_type (part);
    if (header_content_type_is (type, "application", "pkcs7-signature"))
        return FALSE;
    
    /* The second part should be application/pkcs7-signature. */
    part = camel_multipart_get_part (mp, 1);
    type = camel_mime_part_get_content_type (part);
    if (!header_content_type_is (type, "application", "pkcs7-signature"))
        return FALSE;
    
    return TRUE;
}

gboolean
mail_crypto_is_pkcs7_mime (CamelMimePart *mime_part)
{
    char *types[] = { "p7m", "p7c", "p7s", NULL };
    const gchar *param, *filename;
    CamelContentType *type;
    int i;
    
    /* check that we have a application/pkcs7-mime part */
    type = camel_mime_part_get_content_type (mime_part);
    if (header_content_type_is (type, "application", "pkcs7-mime"))
        return TRUE;
    
    if (header_content_type_is (type, "application", "octent-stream")) {
        /* check to see if we have a paremeter called "smime-type" */
        param = header_content_type_param (type, "smime-type");
        if (param)
            return TRUE;
        
        /* check to see if there is a name param and if it has a smime extension */
        param = header_content_type_param (type, "smime-type");
        if (param && *param && strlen (param) > 4) {
            for (i = 0; types[i]; i++)
                if (!g_strcasecmp (param + strlen (param)-4, types[i]))
                    return TRUE;
        }
        
        /* check to see if there is a name param and if it has a smime extension */
        filename = camel_mime_part_get_filename (mime_part);
        if (filename && *filename && strlen (filename) > 4) {
            for (i = 0; types[i]; i++)
                if (!g_strcasecmp (filename + strlen (filename)-4, types[i]))
                    return TRUE;
        }
    }
    
    return FALSE;
}

static void
pgp_mime_part_sign_restore_part (CamelMimePart *mime_part, GSList *encodings)
{
    CamelDataWrapper *wrapper;
    
    wrapper = camel_medium_get_content_object (CAMEL_MEDIUM (mime_part));
    if (!wrapper)
        return;
    
    if (CAMEL_IS_MULTIPART (wrapper)) {
        int parts, i;
        
        parts = camel_multipart_get_number (CAMEL_MULTIPART (wrapper));
        for (i = 0; i < parts; i++) {
            CamelMimePart *part = camel_multipart_get_part (CAMEL_MULTIPART (wrapper), i);
            
            pgp_mime_part_sign_restore_part (part, encodings);
            encodings = encodings->next;
        }
    } else {
        CamelMimePartEncodingType encoding;
        
        encoding = GPOINTER_TO_INT (encodings->data);
        
        camel_mime_part_set_encoding (mime_part, encoding);
    }
}

static void
pgp_mime_part_sign_prepare_part (CamelMimePart *mime_part, GSList **encodings)
{
    CamelDataWrapper *wrapper;
    int parts, i;
    
    wrapper = camel_medium_get_content_object (CAMEL_MEDIUM (mime_part));
    if (!wrapper)
        return;
    
    if (CAMEL_IS_MULTIPART (wrapper)) {
        parts = camel_multipart_get_number (CAMEL_MULTIPART (wrapper));
        for (i = 0; i < parts; i++) {
            CamelMimePart *part = camel_multipart_get_part (CAMEL_MULTIPART (wrapper), i);
            
            pgp_mime_part_sign_prepare_part (part, encodings);
        }
    } else {
        CamelMimePartEncodingType encoding;
        
        encoding = camel_mime_part_get_encoding (mime_part);
        
        /* the encoding should really be QP or Base64 */
        if (encoding != CAMEL_MIME_PART_ENCODING_BASE64)
            camel_mime_part_set_encoding (mime_part, CAMEL_MIME_PART_ENCODING_QUOTEDPRINTABLE);
        
        *encodings = g_slist_append (*encodings, GINT_TO_POINTER (encoding));
    }
}


/**
 * pgp_mime_part_sign:
 * @mime_part: a MIME part that will be replaced by a pgp signed part
 * @userid: userid to sign with
 * @hash: one of PGP_HASH_TYPE_MD5 or PGP_HASH_TYPE_SHA1
 * @ex: exception which will be set if there are any errors.
 *
 * Constructs a PGP/MIME multipart in compliance with rfc2015 and
 * replaces #part with the generated multipart/signed. On failure,
 * #ex will be set and #part will remain untouched.
 **/
void
pgp_mime_part_sign (CamelMimePart **mime_part, const gchar *userid, PgpHashType hash, CamelException *ex)
{
    CamelMimePart *part, *signed_part;
    CamelMultipart *multipart;
    CamelContentType *mime_type;
    CamelStreamFilter *filtered_stream;
    CamelMimeFilter *crlf_filter, *from_filter;
    CamelStream *stream;
    GByteArray *content;
    gchar *signature;
    gchar *hash_type = NULL;
    GSList *encodings = NULL;
    
    g_return_if_fail (*mime_part != NULL);
    g_return_if_fail (CAMEL_IS_MIME_PART (*mime_part));
    g_return_if_fail (userid != NULL);
    g_return_if_fail (hash != PGP_HASH_TYPE_NONE);
    
    part = *mime_part;
    
    /* Prepare all the parts for signing... */
    pgp_mime_part_sign_prepare_part (part, &encodings);
    
    /* get the cleartext */
    content = g_byte_array_new ();
    stream = camel_stream_mem_new ();
    camel_stream_mem_set_byte_array (CAMEL_STREAM_MEM (stream), content);
    crlf_filter = camel_mime_filter_crlf_new (CAMEL_MIME_FILTER_CRLF_ENCODE,
                          CAMEL_MIME_FILTER_CRLF_MODE_CRLF_ONLY);
    from_filter = CAMEL_MIME_FILTER (camel_mime_filter_from_new ());
    filtered_stream = camel_stream_filter_new_with_stream (stream);
    camel_stream_filter_add (filtered_stream, CAMEL_MIME_FILTER (crlf_filter));
    camel_object_unref (CAMEL_OBJECT (crlf_filter));
    camel_stream_filter_add (filtered_stream, CAMEL_MIME_FILTER (from_filter));
    camel_object_unref (CAMEL_OBJECT (from_filter));
    camel_data_wrapper_write_to_stream (CAMEL_DATA_WRAPPER (part), CAMEL_STREAM (filtered_stream));
    camel_object_unref (CAMEL_OBJECT (filtered_stream));
    camel_object_unref (CAMEL_OBJECT (stream));
    
    /* get the signature */
    signature = openpgp_sign (content->data, content->len, userid, hash, ex);
    g_byte_array_free (content, TRUE);
    if (camel_exception_is_set (ex)) {
        /* restore the original encoding */
        pgp_mime_part_sign_restore_part (part, encodings);
        g_slist_free (encodings);
        return;
    }
    
    /* we don't need these anymore... */
    g_slist_free (encodings);
    
    /* construct the pgp-signature mime part */
    fprintf (stderr, "signature:\n%s\n", signature);
    signed_part = camel_mime_part_new ();
    camel_mime_part_set_content (signed_part, signature, strlen (signature),
                     "application/pgp-signature");
    g_free (signature);
    
    /* construct the container multipart/signed */
    switch (hash) {
    case PGP_HASH_TYPE_MD5:
        hash_type = "pgp-md5";
        break;
    case PGP_HASH_TYPE_SHA1:
        hash_type = "pgp-sha1";
        break;
    default:
        g_assert_not_reached ();
    }
    
    multipart = camel_multipart_new ();
    
    mime_type = header_content_type_new ("multipart", "signed");
    header_content_type_set_param (mime_type, "micalg", hash_type);
    header_content_type_set_param (mime_type, "protocol", "application/pgp-signature");
    camel_data_wrapper_set_mime_type_field (CAMEL_DATA_WRAPPER (multipart), mime_type);
    header_content_type_unref (mime_type);
    
    camel_multipart_set_boundary (multipart, NULL);
    
    /* add the parts to the multipart */
    camel_multipart_add_part (multipart, part);
    camel_object_unref (CAMEL_OBJECT (part));
    camel_multipart_add_part (multipart, signed_part);
    camel_object_unref (CAMEL_OBJECT (signed_part));
    
    /* replace the input part with the output part */
    *mime_part = camel_mime_part_new ();
    camel_medium_set_content_object (CAMEL_MEDIUM (*mime_part),
                     CAMEL_DATA_WRAPPER (multipart));
    camel_object_unref (CAMEL_OBJECT (multipart));
}


/**
 * pgp_mime_part_verify:
 * @mime_part: a multipart/signed MIME Part
 * @ex: exception
 *
 * Returns a PgpValidity on success or NULL on fail.
 **/
PgpValidity *
pgp_mime_part_verify (CamelMimePart *mime_part, CamelException *ex)
{
    CamelDataWrapper *wrapper;
    CamelMultipart *multipart;
    CamelMimePart *part, *sigpart;
    CamelStreamFilter *filtered_stream;
    CamelMimeFilter *crlf_filter;
    CamelStream *stream;
    GByteArray *content, *signature;
    PgpValidity *valid;
    
    g_return_val_if_fail (mime_part != NULL, NULL);
    g_return_val_if_fail (CAMEL_IS_MIME_PART (mime_part), NULL);
    
    if (!mail_crypto_is_rfc2015_signed (mime_part))
        return NULL;
    
    wrapper = camel_medium_get_content_object (CAMEL_MEDIUM (mime_part));
    multipart = CAMEL_MULTIPART (wrapper);
    
    /* get the plain part */
    part = camel_multipart_get_part (multipart, 0);
    content = g_byte_array_new ();
    stream = camel_stream_mem_new ();
    camel_stream_mem_set_byte_array (CAMEL_STREAM_MEM (stream), content);
    crlf_filter = camel_mime_filter_crlf_new (CAMEL_MIME_FILTER_CRLF_ENCODE, CAMEL_MIME_FILTER_CRLF_MODE_CRLF_ONLY);
    filtered_stream = camel_stream_filter_new_with_stream (stream);
    camel_stream_filter_add (filtered_stream, CAMEL_MIME_FILTER (crlf_filter));
    camel_object_unref (CAMEL_OBJECT (crlf_filter));
    camel_data_wrapper_write_to_stream (CAMEL_DATA_WRAPPER (part), CAMEL_STREAM (filtered_stream));
    camel_object_unref (CAMEL_OBJECT (filtered_stream));
    camel_object_unref (CAMEL_OBJECT (stream));
    
    /* get the signed part */
    sigpart = camel_multipart_get_part (multipart, 1);
    signature = g_byte_array_new ();
    stream = camel_stream_mem_new ();
    camel_stream_mem_set_byte_array (CAMEL_STREAM_MEM (stream), signature);
    camel_data_wrapper_write_to_stream (camel_medium_get_content_object (CAMEL_MEDIUM (sigpart)), stream);
    camel_object_unref (CAMEL_OBJECT (stream));
    
    /* verify */
    valid = openpgp_verify (content->data, content->len,
                signature->data, signature->len, ex);
    
    g_byte_array_free (content, TRUE);
    g_byte_array_free (signature, TRUE);
    
    return valid;
}


/**
 * pgp_mime_part_encrypt:
 * @mime_part: a MIME part that will be replaced by a pgp encrypted part
 * @recipients: list of recipient PGP Key IDs
 * @ex: exception which will be set if there are any errors.
 *
 * Constructs a PGP/MIME multipart in compliance with rfc2015 and
 * replaces #mime_part with the generated multipart/signed. On failure,
 * #ex will be set and #part will remain untouched.
 **/
void
pgp_mime_part_encrypt (CamelMimePart **mime_part, const GPtrArray *recipients, CamelException *ex)
{
    CamelMultipart *multipart;
    CamelMimePart *part, *version_part, *encrypted_part;
    CamelContentType *mime_type;
    CamelStreamFilter *filtered_stream;
    CamelMimeFilter *crlf_filter;
    CamelStream *stream;
    GByteArray *content;
    gchar *ciphertext;
    
    g_return_if_fail (*mime_part != NULL);
    g_return_if_fail (CAMEL_IS_MIME_PART (*mime_part));
    g_return_if_fail (recipients != NULL);
    
    part = *mime_part;
    
    /* get the contents */
        content = g_byte_array_new ();
    stream = camel_stream_mem_new ();
    camel_stream_mem_set_byte_array (CAMEL_STREAM_MEM (stream), content);
    crlf_filter = camel_mime_filter_crlf_new (CAMEL_MIME_FILTER_CRLF_ENCODE,
                          CAMEL_MIME_FILTER_CRLF_MODE_CRLF_ONLY);
    filtered_stream = camel_stream_filter_new_with_stream (stream);
    camel_stream_filter_add (filtered_stream, CAMEL_MIME_FILTER (crlf_filter));
    camel_object_unref (CAMEL_OBJECT (crlf_filter));
    camel_data_wrapper_write_to_stream (CAMEL_DATA_WRAPPER (part), CAMEL_STREAM (filtered_stream));
    camel_object_unref (CAMEL_OBJECT (filtered_stream));
    camel_object_unref (CAMEL_OBJECT (stream));
    
    /* pgp encrypt */
    ciphertext = openpgp_encrypt (content->data,
                      content->len,
                      recipients, FALSE, NULL, ex);
    g_byte_array_free (content, TRUE);
    if (camel_exception_is_set (ex))
        return;
    
    /* construct the version part */
    version_part = camel_mime_part_new ();
    camel_mime_part_set_encoding (version_part, CAMEL_MIME_PART_ENCODING_7BIT);
    camel_mime_part_set_content (version_part, "Version: 1", strlen ("Version: 1"),
                     "application/pgp-encrypted");
    
    /* construct the pgp-encrypted mime part */
    encrypted_part = camel_mime_part_new ();
    camel_mime_part_set_encoding (encrypted_part, CAMEL_MIME_PART_ENCODING_7BIT);
    camel_mime_part_set_content (encrypted_part, ciphertext, strlen (ciphertext),
                     "application/octet-stream");
    g_free (ciphertext);
    
    /* construct the container multipart/signed */
    multipart = camel_multipart_new ();
    
    mime_type = header_content_type_new ("multipart", "encrypted");
    header_content_type_set_param (mime_type, "protocol", "application/pgp-encrypted");
    camel_data_wrapper_set_mime_type_field (CAMEL_DATA_WRAPPER (multipart), mime_type);
    header_content_type_unref (mime_type);
    
    camel_multipart_set_boundary (multipart, NULL);
    
    /* add the parts to the multipart */
    camel_multipart_add_part (multipart, version_part);
    camel_object_unref (CAMEL_OBJECT (version_part));
    camel_multipart_add_part (multipart, encrypted_part);
    camel_object_unref (CAMEL_OBJECT (encrypted_part));
    
    /* replace the input part with the output part */
    camel_object_unref (CAMEL_OBJECT (*mime_part));
    *mime_part = camel_mime_part_new ();
    camel_medium_set_content_object (CAMEL_MEDIUM (*mime_part),
                     CAMEL_DATA_WRAPPER (multipart));
    camel_object_unref (CAMEL_OBJECT (multipart));
}


/**
 * pgp_mime_part_decrypt:
 * @mime_part: a multipart/encrypted MIME Part
 * @ex: exception
 *
 * Returns the decrypted MIME Part on success or NULL on fail.
 **/
CamelMimePart *
pgp_mime_part_decrypt (CamelMimePart *mime_part, CamelException *ex)
{
    CamelDataWrapper *wrapper;
    CamelMultipart *multipart;
    CamelMimePart *encrypted_part, *part;
    CamelContentType *mime_type;
    CamelStream *stream;
    GByteArray *content;
    gchar *cleartext;
    int clearlen;
    
    g_return_val_if_fail (mime_part != NULL, NULL);
    g_return_val_if_fail (CAMEL_IS_MIME_PART (mime_part), NULL);
    
    /* make sure the mime part is a multipart/encrypted */
    if (!mail_crypto_is_rfc2015_encrypted (mime_part))
        return NULL;
    
    wrapper = camel_medium_get_content_object (CAMEL_MEDIUM (mime_part));
    multipart = CAMEL_MULTIPART (wrapper);
    
    /* get the encrypted part (second part) */
    encrypted_part = camel_multipart_get_part (multipart, 1 /* second part starting at 0 */);
    mime_type = camel_mime_part_get_content_type (encrypted_part);
    if (!header_content_type_is (mime_type, "application", "octet-stream"))
        return NULL;
    
    /* get the ciphertext */
    content = g_byte_array_new ();
    stream = camel_stream_mem_new ();
    camel_stream_mem_set_byte_array (CAMEL_STREAM_MEM (stream), content);
    camel_data_wrapper_write_to_stream (CAMEL_DATA_WRAPPER (encrypted_part), stream);
    camel_object_unref (CAMEL_OBJECT (stream));
    
    /* get the cleartext */
    cleartext = openpgp_decrypt (content->data, content->len, &clearlen, ex);
    g_byte_array_free (content, TRUE);
    if (camel_exception_is_set (ex))
        return NULL;
    
    /* create a stream based on the returned cleartext */
    stream = camel_stream_mem_new_with_buffer (cleartext, clearlen);
    g_free (cleartext);
    
    /* construct the new decrypted mime part from the stream */
    part = camel_mime_part_new ();
    camel_data_wrapper_construct_from_stream (CAMEL_DATA_WRAPPER (part), stream);
    camel_object_unref (CAMEL_OBJECT (stream));
    
    return part;
}