Commit 1c378b2d authored by Rafaël Carré's avatar Rafaël Carré

Update mechanism: split update.c

Move cryptography specific functions into their own file, together with
functions downloading public key / signatures
Factorize common code for generating signatures (hash_sha1_from_*)
Remove unused update_WaitDownload (was OSX specific)
parent 141eb5a6
......@@ -63,7 +63,6 @@ VLC_EXPORT( void, update_Check, ( update_t *, void (*callback)( void*, bool ), v
VLC_EXPORT( bool, update_NeedUpgrade, ( update_t * ) );
VLC_EXPORT( void, update_Download, ( update_t *, const char* ) );
VLC_EXPORT( update_release_t*, update_GetRelease, ( update_t * ) );
VLC_EXPORT( void, update_WaitDownload, ( update_t * ) );
/**
* @}
......
......@@ -417,6 +417,7 @@ SOURCES_libvlc_common = \
misc/error.c \
misc/update.h \
misc/update.c \
misc/update_crypto.c \
misc/xml.c \
misc/devices.c \
extras/libc.c \
......
......@@ -99,944 +99,6 @@ 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;
}
}
return crc & 0xFFFFFFL;
}
/*
* Transform an armored document in binary format
* Used on public keys and signatures
*/
static int pgp_unarmor( char *p_ibuf, size_t i_ibuf_len,
uint8_t *p_obuf, size_t i_obuf_len )
{
char *p_ipos = p_ibuf;
uint8_t *p_opos = p_obuf;
int i_end = 0;
int i_header_skipped = 0;
while( !i_end && p_ipos < p_ibuf + i_ibuf_len && *p_ipos != '=' )
{
if( *p_ipos == '\r' || *p_ipos == '\n' )
{
p_ipos++;
continue;
}
size_t i_line_len = strcspn( p_ipos, "\r\n" );
if( i_line_len == 0 )
continue;
if( !i_header_skipped )
{
if( !strncmp( p_ipos, "-----BEGIN PGP", 14 ) )
i_header_skipped = 1;
p_ipos += i_line_len + 1;
continue;
}
if( !strncmp( p_ipos, "Version:", 8 ) )
{
p_ipos += i_line_len + 1;
continue;
}
if( p_ipos[i_line_len - 1] == '=' )
{
i_end = 1;
p_ipos[i_line_len - 1] = '\0';
}
else
p_ipos[i_line_len] = '\0';
p_opos += vlc_b64_decode_binary_to_buffer( p_opos,
p_obuf - p_opos + i_obuf_len, p_ipos );
p_ipos += i_line_len + 1;
}
/* XXX: the CRC is OPTIONAL, really require it ? */
if( p_ipos + 5 > p_ibuf + i_ibuf_len || *p_ipos++ != '=' )
return 0;
uint8_t p_crc[3];
if( vlc_b64_decode_binary_to_buffer( p_crc, 3, p_ipos ) != 3 )
return 0;
long l_crc = crc_octets( p_obuf, p_opos - p_obuf );
long l_crc2 = ( 0 << 24 ) + ( p_crc[0] << 16 ) + ( p_crc[1] << 8 ) + p_crc[2];
return l_crc2 == l_crc ? p_opos - p_obuf : 0;
}
/*
* Download the signature associated to a document or a binary file.
* We're given the file's url, we just append ".asc" to it and download
*/
static int download_signature( vlc_object_t *p_this,
signature_packet_t *p_sig,
const char *psz_url )
{
char *psz_sig = (char*) malloc( strlen( psz_url ) + 4 + 1 ); /* ".asc" + \0 */
if( !psz_sig )
return VLC_ENOMEM;
strcpy( psz_sig, psz_url );
strcat( psz_sig, ".asc" );
stream_t *p_stream = stream_UrlNew( p_this, psz_sig );
free( psz_sig );
if( !p_stream )
return VLC_ENOMEM;
int64_t i_size = stream_Size( p_stream );
msg_Dbg( p_this, "Downloading signature (%"PRId64" bytes)", i_size );
uint8_t *p_buf = (uint8_t*)malloc( i_size );
if( !p_buf )
{
stream_Delete( p_stream );
return VLC_ENOMEM;
}
int i_read = stream_Read( p_stream, p_buf, (int)i_size );
stream_Delete( p_stream );
if( i_read != (int)i_size )
{
msg_Dbg( p_this,
"Couldn't download full signature (only %d bytes)", i_read );
free( p_buf );
return VLC_EGENERIC;
}
if( (uint8_t)*p_buf < 0x80 ) /* ASCII */
{
msg_Dbg( p_this, "Unarmoring signature" );
uint8_t* p_unarmored = (uint8_t*) malloc( ( i_size * 3 ) / 4 + 1 );
if( !p_unarmored )
{
free( p_buf );
return VLC_EGENERIC;
}
int i_bytes = pgp_unarmor( (char*)p_buf, i_size, p_unarmored, i_size );
free( p_buf );
p_buf = p_unarmored;
i_size = i_bytes;
if( i_bytes < 2 )
{
free( p_buf );
msg_Dbg( p_this, "Unarmoring failed : corrupted signature ?" );
return VLC_EGENERIC;
}
}
if( packet_type( *p_buf ) != SIGNATURE_PACKET )
{
free( p_buf );
msg_Dbg( p_this, "Not a signature: %d", *p_buf );
return VLC_EGENERIC;
}
size_t i_header_len = packet_header_len( *p_buf );
if( ( i_header_len != 1 && i_header_len != 2 && i_header_len != 4 ) ||
i_header_len + 1 > (size_t)i_size )
{
free( p_buf );
msg_Dbg( p_this, "Invalid signature packet header" );
return VLC_EGENERIC;
}
size_t i_len = scalar_number( p_buf+1, i_header_len );
if( i_len + i_header_len + 1 != (size_t)i_size )
{
free( p_buf );
msg_Dbg( p_this, "Invalid signature packet" );
return VLC_EGENERIC;
}
int i_ret = parse_signature_packet( p_sig, p_buf+1+i_header_len, i_len );
free( p_buf );
if( i_ret != VLC_SUCCESS )
{
msg_Dbg( p_this, "Couldn't parse signature" );
return i_ret;
}
if( p_sig->type != BINARY_SIGNATURE && p_sig->type != TEXT_SIGNATURE )
{
msg_Dbg( p_this, "Invalid signature type: %d", p_sig->type );
if( p_sig->version == 4 )
{
free( p_sig->specific.v4.hashed_data );
free( p_sig->specific.v4.unhashed_data );
}
return VLC_EGENERIC;
}
return VLC_SUCCESS;
}
/*
* Verify an OpenPGP signature made on some SHA-1 hash, with some DSA public key
*/
static int verify_signature( uint8_t *p_r, uint8_t *p_s,
public_key_packet_t *p_key, uint8_t *p_hash )
{
/* the data to be verified (a SHA-1 hash) */
const char *hash_sexp_s = "(data(flags raw)(value %m))";
/* the public key */
const char *key_sexp_s = "(public-key(dsa(p %m)(q %m)(g %m)(y %m)))";
/* the signature */
const char *sig_sexp_s = "(sig-val(dsa(r %m )(s %m )))";
size_t erroff;
gcry_mpi_t p, q, g, y, r, s, hash;
p = q = g = y = r = s = hash = NULL;
gcry_sexp_t key_sexp, hash_sexp, sig_sexp;
key_sexp = hash_sexp = sig_sexp = NULL;
int i_p_len = mpi_len( p_key->p );
int i_q_len = mpi_len( p_key->q );
int i_g_len = mpi_len( p_key->g );
int i_y_len = mpi_len( p_key->y );
if( gcry_mpi_scan( &p, GCRYMPI_FMT_USG, p_key->p + 2, i_p_len, NULL ) ||
gcry_mpi_scan( &q, GCRYMPI_FMT_USG, p_key->q + 2, i_q_len, NULL ) ||
gcry_mpi_scan( &g, GCRYMPI_FMT_USG, p_key->g + 2, i_g_len, NULL ) ||
gcry_mpi_scan( &y, GCRYMPI_FMT_USG, p_key->y + 2, i_y_len, NULL ) ||
gcry_sexp_build( &key_sexp, &erroff, key_sexp_s, p, q, g, y ) )
goto problem;
int i_r_len = mpi_len( p_r );
int i_s_len = mpi_len( p_s );
if( gcry_mpi_scan( &r, GCRYMPI_FMT_USG, p_r + 2, i_r_len, NULL ) ||
gcry_mpi_scan( &s, GCRYMPI_FMT_USG, p_s + 2, i_s_len, NULL ) ||
gcry_sexp_build( &sig_sexp, &erroff, sig_sexp_s, r, s ) )
goto problem;
int i_hash_len = 20;
if( gcry_mpi_scan( &hash, GCRYMPI_FMT_USG, p_hash, i_hash_len, NULL ) ||
gcry_sexp_build( &hash_sexp, &erroff, hash_sexp_s, hash ) )
goto problem;
if( gcry_pk_verify( sig_sexp, hash_sexp, key_sexp ) )
goto problem;
return VLC_SUCCESS;
problem:
if( p ) gcry_mpi_release( p );
if( q ) gcry_mpi_release( q );
if( g ) gcry_mpi_release( g );
if( y ) gcry_mpi_release( y );
if( r ) gcry_mpi_release( r );
if( s ) gcry_mpi_release( s );
if( hash ) gcry_mpi_release( hash );
if( key_sexp ) gcry_sexp_release( key_sexp );
if( sig_sexp ) gcry_sexp_release( sig_sexp );
if( hash_sexp ) gcry_sexp_release( hash_sexp );
return VLC_EGENERIC;
}
/*
* fill a public_key_t with public key data, including:
* * public key packet
* * signature packet issued by key which long id is p_sig_issuer
* * user id packet
*/
static int parse_public_key( const uint8_t *p_key_data, size_t i_key_len,
public_key_t *p_key, const uint8_t *p_sig_issuer )
{
uint8_t *pos = (uint8_t*) p_key_data;
uint8_t *max_pos = pos + i_key_len;
int i_status = 0;
#define PUBLIC_KEY_FOUND 0x01
#define USER_ID_FOUND 0x02
#define SIGNATURE_FOUND 0X04
uint8_t *p_key_unarmored = NULL;
p_key->psz_username = NULL;
p_key->sig.specific.v4.hashed_data = NULL;
p_key->sig.specific.v4.unhashed_data = NULL;
if( !( *pos & 0x80 ) )
{ /* first byte is ASCII, unarmoring */
p_key_unarmored = (uint8_t*)malloc( i_key_len );
if( !p_key_unarmored )
return VLC_ENOMEM;
int i_len = pgp_unarmor( (char*)p_key_data, i_key_len,
p_key_unarmored, i_key_len );
if( i_len == 0 )
goto error;
pos = p_key_unarmored;
max_pos = pos + i_len;