security-and-privacy/gnupg
security-and-privacy/gnupg
1
0
Fork 0
mirror of git://git.gnupg.org/gnupg.git synced 2025-07-02 22:46:30 +02:00
Code Activity

See ChangeLog: Mon Apr 26 17:48:15 CEST 1999 Werner Koch

Browse source
This commit is contained in:
Werner Koch 1999-04-26 15:53:01 +00:00
parent ebb0ed57c7
commit bbf86c6e59
32 changed files with 866 additions and 265 deletions
Download patch file Download diff file Expand all files Collapse all files

91
g10/sig-check.c
View file

@ -45,7 +45,7 @@ static int do_check( PKT_public_key *pk, PKT_signature *sig,
/****************
* Check the signature which is contained in SIG.
* The md5handle should be currently open, so that this function
* The MD_HANDLE should be currently open, so that this function
* is able to append some data, before finalizing the digest.
*/
int
@ -54,7 +54,6 @@ signature_check( PKT_signature *sig, MD_HANDLE digest )
PKT_public_key *pk = m_alloc_clear( sizeof *pk );
int rc=0;
if( is_RSA(sig->pubkey_algo) )
write_status(STATUS_RSA_OR_IDEA);
@ -108,6 +107,94 @@ signature_check( PKT_signature *sig, MD_HANDLE digest )
}
/****************
* Check the MDC which is contained in SIG.
* The MD_HANDLE should be currently open, so that this function
* is able to append some data, before finalizing the digest.
*/
int
mdc_kludge_check( PKT_signature *sig, MD_HANDLE digest )
{
int rc=0;
if( (rc=check_digest_algo(sig->digest_algo)) )
return rc;
/* make sure the digest algo is enabled (in case of a detached mdc??) */
md_enable( digest, sig->digest_algo );
/* complete the digest */
if( sig->version >= 4 )
md_putc( digest, sig->version );
md_putc( digest, sig->sig_class );
if( sig->version < 4 ) {
u32 a = sig->timestamp;
md_putc( digest, (a >> 24) & 0xff );
md_putc( digest, (a >> 16) & 0xff );
md_putc( digest, (a >> 8) & 0xff );
md_putc( digest, a & 0xff );
}
else {
byte buf[6];
size_t n;
md_putc( digest, sig->pubkey_algo );
md_putc( digest, sig->digest_algo );
if( sig->hashed_data ) {
n = (sig->hashed_data[0] << 8) | sig->hashed_data[1];
md_write( digest, sig->hashed_data, n+2 );
n += 6;
}
else
n = 6;
/* add some magic */
buf[0] = sig->version;
buf[1] = 0xff;
buf[2] = n >> 24;
buf[3] = n >> 16;
buf[4] = n >> 8;
buf[5] = n;
md_write( digest, buf, 6 );
}
md_final( digest );
rc = G10ERR_BAD_SIGN;
{ const byte *s1 = md_read( digest, sig->digest_algo );
int s1len = md_digest_length( sig->digest_algo );
log_hexdump( "MDC calculated", s1, s1len );
if( !sig->data[0] )
log_debug("sig_data[0] is NULL\n");
else {
unsigned s2len;
byte *s2;
s2 = mpi_get_buffer( sig->data[0], &s2len, NULL );
log_hexdump( "MDC stored ", s2, s2len );
if( s2len != s1len )
log_debug("MDC check: len differ: %d/%d\n", s1len, s2len);
else if( memcmp( s1, s2, s1len ) )
log_debug("MDC check: hashs differ\n");
else
rc = 0;
m_free(s2);
}
}
if( !rc && sig->flags.unknown_critical ) {
log_info(_("assuming bad MDC due to an unknown critical bit\n"));
rc = G10ERR_BAD_SIGN;
}
sig->flags.checked = 1;
sig->flags.valid = !rc;
/* FIXME: check that we are actually in an encrypted packet */
return rc;
}
/****************
* This function gets called by pubkey_verify() if the algorithm needs it.
*/