update.c

VLC Player Source Code

/*****************************************************************************
 * update.c: VLC update checking and downloading
 *****************************************************************************
 * Copyright © 2005-2008 the VideoLAN team
 * $Id: 96a3948992f7fdfe5aed37b0fe3d8565272d2237 $
 *
 * Authors: Antoine Cellerier <dionoea -at- videolan -dot- org>
 *          Rémi Duraffort <ivoire at via.ecp.fr>
            Rafaël Carré <funman@videolanorg>
 *
 * 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 release 2 of the License, or
 * (at your option) any later release.
 *
 * 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, USA.
 *****************************************************************************/

/**
 *   \file
 *   This file contains functions related to VLC update management
 */

/*****************************************************************************
 * Preamble
 *****************************************************************************/

#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#include <vlc_common.h>
#include <vlc_update.h>

#ifdef UPDATE_CHECK

#include <assert.h>

#include <vlc_pgpkey.h>
#include <vlc_stream.h>
#include <vlc_strings.h>
#include <vlc_charset.h>
#include <vlc_interface.h>

#include <gcrypt.h>
#include <vlc_gcrypt.h>

#include "update.h"
#include "../libvlc.h"

/*****************************************************************************
 * Misc defines
 *****************************************************************************/

/*
 * Here is the format of these "status files" :
 * First line is the last version: "X.Y.Ze" where:
 *      * X is the major number
 *      * Y is the minor number
 *      * Z is the revision number
 *      * e is an OPTIONAL extra letter
 *      * AKA "0.8.6d" or "0.9.0"
 * Second line is an url of the binary for this last version
 * Remaining text is a required description of the update
 */

#if defined( UNDER_CE )
#   define UPDATE_VLC_STATUS_URL "http://update.videolan.org/vlc/status-ce"
#elif defined( WIN32 )
#   define UPDATE_VLC_STATUS_URL "http://update.videolan.org/vlc/status-win-x86"
#elif defined( __APPLE__ )
#   if defined( __powerpc__ ) || defined( __ppc__ ) || defined( __ppc64__ )
#       define UPDATE_VLC_STATUS_URL "http://update.videolan.org/vlc/status-mac-ppc"
#   else
#       define UPDATE_VLC_STATUS_URL "http://update.videolan.org/vlc/status-mac-x86"
#   endif
#elif defined( SYS_BEOS )
#       define UPDATE_VLC_STATUS_URL "http://update.videolan.org/vlc/status-beos-x86"
#else
#   define UPDATE_VLC_STATUS_URL "http://update.videolan.org/vlc/status"
#endif


/*****************************************************************************
 * Local Prototypes
 *****************************************************************************/
static void EmptyRelease( update_t *p_update );
static bool GetUpdateFile( update_t *p_update );
static char * size_str( long int l_size );


/*****************************************************************************
 * OpenPGP functions
 *****************************************************************************/

#define packet_type( c ) ( ( c & 0x3c ) >> 2 )      /* 0x3C = 00111100 */
#define packet_header_len( c ) ( ( c & 0x03 ) + 1 ) /* number of bytes in a packet header */

static inline int scalar_number( uint8_t *p, int header_len )
{
    assert( header_len == 1 || header_len == 2 || header_len == 4 );

    if( header_len == 1 )
        return( p[0] );
    else if( header_len == 2 )
        return( (p[0] << 8) + p[1] );
    else if( header_len == 4 )
        return( (p[0] << 24) + (p[1] << 16) + (p[2] << 8) + p[3] );

    abort(); /* to shut up GCC warning */
}

/* number of data bytes in a MPI */
#define mpi_len( mpi ) ( ( scalar_number( mpi, 2 ) + 7 ) / 8 )

/*
 * fill a public_key_packet_t structure from public key packet data
 * verify that it is a version 4 public key packet, using DSA
 */
static int parse_public_key_packet( public_key_packet_t *p_key, uint8_t *p_buf,
                                    size_t i_packet_len )
{

    if( i_packet_len > 418 || i_packet_len < 6 )
        return VLC_EGENERIC;

    size_t i_read = 0;

    p_key->version   = *p_buf++; i_read++;
    if( p_key->version != 4 )
        return VLC_EGENERIC;

    /* XXX: warn when timestamp is > date ? */
    memcpy( p_key->timestamp, p_buf, 4 ); p_buf += 4; i_read += 4;

    p_key->algo      = *p_buf++; i_read++;
    if( p_key->algo != PUBLIC_KEY_ALGO_DSA )
        return VLC_EGENERIC;

    /* read p */
    if( i_read + 2 > i_packet_len )
        return VLC_EGENERIC;

    int i_p_len = mpi_len( p_buf );

    if( i_p_len > 128 || i_read + 2 + i_p_len > i_packet_len )
        return VLC_EGENERIC;

    memcpy( p_key->p, p_buf, 2+i_p_len );
    p_buf += 2+i_p_len; i_read += 2+i_p_len;

    /* read q */
    if( i_read + 2 > i_packet_len )
        return VLC_EGENERIC;

    int i_q_len = mpi_len( p_buf );

    if( i_q_len > 20 || i_read+2+i_q_len > i_packet_len )
        return VLC_EGENERIC;

    memcpy( p_key->q, p_buf, 2+i_q_len );
    p_buf += 2+i_q_len; i_read += 2+i_q_len;

    /* read g */
    if( i_read + 2 > i_packet_len )
        return VLC_EGENERIC;

    int i_g_len = mpi_len( p_buf );

    if( i_g_len > 128 || i_read+2+i_g_len > i_packet_len )
        return VLC_EGENERIC;

    memcpy( p_key->g, p_buf, 2+i_g_len );
    p_buf += 2+i_g_len; i_read += 2+i_g_len;

    /* read y */
    if( i_read + 2 > i_packet_len )
        return VLC_EGENERIC;

    int i_y_len = mpi_len( p_buf );


    if( i_y_len > 128 || i_read+2+i_y_len > i_packet_len )
        return VLC_EGENERIC;

    memcpy( p_key->y, p_buf, 2+i_y_len );
    i_read += 2+i_y_len;

    if( i_read != i_packet_len ) /* some extra data eh ? */
        return VLC_EGENERIC;

    return VLC_SUCCESS;
}

static size_t parse_signature_v3_packet( signature_packet_t *p_sig,
                                      uint8_t *p_buf, size_t i_sig_len )
{
    size_t i_read = 1; /* we already read the version byte */

    if( i_sig_len < 19 ) /* signature is at least 19 bytes + the 2 MPIs */
        return 0;

    p_sig->specific.v3.hashed_data_len = *p_buf++; i_read++;
    if( p_sig->specific.v3.hashed_data_len != 5 )
        return 0;

    p_sig->type = *p_buf++; i_read++;

    memcpy( p_sig->specific.v3.timestamp, p_buf, 4 );
    p_buf += 4; i_read += 4;

    memcpy( p_sig->issuer_longid, p_buf, 8 );
    p_buf += 8; i_read += 8;

    p_sig->public_key_algo = *p_buf++; i_read++;

    p_sig->digest_algo = *p_buf++; i_read++;

    p_sig->hash_verification[0] = *p_buf++; i_read++;
    p_sig->hash_verification[1] = *p_buf++; i_read++;

    assert( i_read == 19 );

    return i_read;
}

/*
 * fill a signature_packet_v4_t from signature packet data
 * verify that it was used with a DSA public key, using SHA-1 digest
 */
static size_t parse_signature_v4_packet( signature_packet_t *p_sig,
                                      uint8_t *p_buf, size_t i_sig_len )
{
    size_t i_read = 1; /* we already read the version byte */

    if( i_sig_len < 10 ) /* signature is at least 10 bytes + the 2 MPIs */
        return 0;

    p_sig->type = *p_buf++; i_read++;

    p_sig->public_key_algo = *p_buf++; i_read++;

    p_sig->digest_algo = *p_buf++; i_read++;

    memcpy( p_sig->specific.v4.hashed_data_len, p_buf, 2 );
    p_buf += 2; i_read += 2;

    size_t i_hashed_data_len =
        scalar_number( p_sig->specific.v4.hashed_data_len, 2 );
    i_read += i_hashed_data_len;
    if( i_read + 4 > i_sig_len )
        return 0;

    p_sig->specific.v4.hashed_data = (uint8_t*) malloc( i_hashed_data_len );
    if( !p_sig->specific.v4.hashed_data )
        return 0;
    memcpy( p_sig->specific.v4.hashed_data, p_buf, i_hashed_data_len );
    p_buf += i_hashed_data_len;

    memcpy( p_sig->specific.v4.unhashed_data_len, p_buf, 2 );
    p_buf += 2; i_read += 2;

    size_t i_unhashed_data_len =
        scalar_number( p_sig->specific.v4.unhashed_data_len, 2 );
    i_read += i_unhashed_data_len;
    if( i_read + 2 > i_sig_len )
        return 0;

    p_sig->specific.v4.unhashed_data = (uint8_t*) malloc( i_unhashed_data_len );
    if( !p_sig->specific.v4.unhashed_data )
        return 0;

    memcpy( p_sig->specific.v4.unhashed_data, p_buf, i_unhashed_data_len );
    p_buf += i_unhashed_data_len;

    memcpy( p_sig->hash_verification, p_buf, 2 );
    p_buf += 2; i_read += 2;

    uint8_t *p, *max_pos;
    p = p_sig->specific.v4.unhashed_data;
    max_pos = p + scalar_number( p_sig->specific.v4.unhashed_data_len, 2 );

    for( ;; )
    {
        if( p > max_pos )
            return 0;

        size_t i_subpacket_len;
        if( *p < 192 )
        {
            if( p + 1 > max_pos )
                return 0;
            i_subpacket_len = *p++;
        }
        else if( *p < 255 )
        {
            if( p + 2 > max_pos )
                return 0;
            i_subpacket_len = (*p++ - 192) << 8;
            i_subpacket_len += *p++ + 192;
        }
        else
        {
            if( p + 4 > max_pos )
                return 0;
            i_subpacket_len = *++p << 24;
            i_subpacket_len += *++p << 16;
            i_subpacket_len += *++p << 8;
            i_subpacket_len += *++p;
        }

        if( *p == ISSUER_SUBPACKET )
        {
            if( p + 9 > max_pos )
                return 0;

            memcpy( &p_sig->issuer_longid, p+1, 8 );

            return i_read;
        }

        p += i_subpacket_len;
    }
}

static int parse_signature_packet( signature_packet_t *p_sig,
                                   uint8_t *p_buf, size_t i_sig_len )
{
    if( !i_sig_len ) /* 1st sanity check, we need at least the version */
        return VLC_EGENERIC;

    p_sig->version = *p_buf++;

    size_t i_read;
    switch( p_sig->version )
    {
        case 3:
            i_read = parse_signature_v3_packet( p_sig, p_buf, i_sig_len );
            break;
        case 4:
            p_sig->specific.v4.hashed_data = NULL;
            p_sig->specific.v4.unhashed_data = NULL;
            i_read = parse_signature_v4_packet( p_sig, p_buf, i_sig_len );
            break;
        default:
            return VLC_EGENERIC;
    }

    if( i_read == 0 ) /* signature packet parsing has failed */
        goto error;

    if( p_sig->public_key_algo != PUBLIC_KEY_ALGO_DSA )
        goto error;

    if( p_sig->digest_algo != DIGEST_ALGO_SHA1 )
        goto error;

    switch( p_sig->type )
    {
        case BINARY_SIGNATURE:
        case TEXT_SIGNATURE:
        case GENERIC_KEY_SIGNATURE:
        case PERSONA_KEY_SIGNATURE:
        case CASUAL_KEY_SIGNATURE:
        case POSITIVE_KEY_SIGNATURE:
            break;
        default:
            goto error;
    }

    p_buf--; /* rewind to the version byte */
    p_buf += i_read;

    if( i_read + 2 > i_sig_len )
        goto error;

    size_t i_r_len = mpi_len( p_buf ); i_read += 2;
    if( i_read + i_r_len > i_sig_len || i_r_len > 20 )
        goto error;

    memcpy( p_sig->r, p_buf, 2 + i_r_len );
    p_buf += 2 + i_r_len;
    i_read += i_r_len;

    if( i_read + 2 > i_sig_len )
        goto error;

    size_t i_s_len = mpi_len( p_buf ); i_read += 2;
    if( i_read + i_s_len > i_sig_len || i_s_len > 20 )
        goto error;

    memcpy( p_sig->s, p_buf, 2 + i_s_len );
    p_buf += 2 + i_s_len;
    i_read += i_s_len;

    assert( i_read == i_sig_len );
    if( i_read < i_sig_len ) /* some extra data, hm ? */
        goto error;

    return VLC_SUCCESS;

error:

    if( p_sig->version == 4 )
    {
        free( p_sig->specific.v4.hashed_data );
        free( p_sig->specific.v4.unhashed_data );
    }

    return VLC_EGENERIC;
}

/*
 * crc_octets() was lamely copied from rfc 2440
 * Copyright (C) The Internet Society (1998).  All Rights Reserved.
 */
#define CRC24_INIT 0xB704CEL
#define CRC24_POLY 0x1864CFBL

static long crc_octets( uint8_t *octets, size_t len )
{
    long crc = CRC24_INIT;
    int i;
    while (len--)
    {
        crc ^= (*octets++) << 16;
        for (i = 0; i < 8; i++)
        {
            crc <<= 1;
            if (crc & 0x1000000)
                crc ^= CRC24_POLY;
        }