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partial DSA support

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This commit is contained in:
Werner Koch 1998-03-09 21:44:06 +00:00
parent 1b1a6d7e77
commit a6a8f1e706
62 changed files with 2247 additions and 447 deletions
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88
g10/sig-check.c
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@ -66,11 +66,11 @@ do_check( PKT_public_cert *pkc, PKT_signature *sig, MD_HANDLE digest )
if( pkc->pubkey_algo == PUBKEY_ALGO_ELGAMAL ) {
ELG_public_key pkey;
if( (rc=check_digest_algo(sig->d.elg.digest_algo)) )
if( (rc=check_digest_algo(sig->digest_algo)) )
goto leave;
/* make sure the digest algo is enabled (in case of a detached
* signature */
md_enable( digest, sig->d.elg.digest_algo );
md_enable( digest, sig->digest_algo );
/* complete the digest */
md_putc( digest, sig->sig_class );
{ u32 a = sig->timestamp;
@ -87,6 +87,59 @@ do_check( PKT_public_cert *pkc, PKT_signature *sig, MD_HANDLE digest )
if( !elg_verify( sig->d.elg.a, sig->d.elg.b, result, &pkey ) )
rc = G10ERR_BAD_SIGN;
}
else if( pkc->pubkey_algo == PUBKEY_ALGO_DSA ) {
DSA_public_key pkey;
if( (rc=check_digest_algo(sig->digest_algo)) )
goto leave;
/* make sure the digest algo is enabled (in case of a detached
* signature */
md_enable( digest, sig->digest_algo );
assert( sig->digest_algo == DIGEST_ALGO_SHA1 );
/* 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 += 4;
}
else
n = 4;
/* 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 );
log_hexdump("digest is: ", md_read(digest, DIGEST_ALGO_SHA1), 20);
result = encode_md_value( digest, mpi_get_nbits(pkc->d.dsa.p));
pkey.p = pkc->d.dsa.p;
pkey.q = pkc->d.dsa.q;
pkey.g = pkc->d.dsa.g;
pkey.y = pkc->d.dsa.y;
if( !dsa_verify( sig->d.dsa.r, sig->d.dsa.s, result, &pkey ) )
rc = G10ERR_BAD_SIGN;
}
#ifdef HAVE_RSA_CIPHER
else if( pkc->pubkey_algo == PUBKEY_ALGO_RSA ) {
int i, j, c, old_enc;
@ -125,10 +178,10 @@ do_check( PKT_public_cert *pkc, PKT_signature *sig, MD_HANDLE digest )
goto leave;
}
if( (rc=check_digest_algo(sig->d.rsa.digest_algo)) )
if( (rc=check_digest_algo(sig->digest_algo)) )
goto leave; /* unsupported algo */
md_enable( digest, sig->d.rsa.digest_algo );
asn = md_asn_oid( sig->d.rsa.digest_algo, &asnlen, &mdlen );
md_enable( digest, sig->digest_algo );
asn = md_asn_oid( sig->digest_algo, &asnlen, &mdlen );
for(i=mdlen,j=asnlen-1; (c=mpi_getbyte(result, i)) != -1 && j >= 0;
i++, j-- )
@ -142,7 +195,7 @@ do_check( PKT_public_cert *pkc, PKT_signature *sig, MD_HANDLE digest )
if( c != 0xff )
break;
i++;
if( c != sig->d.rsa.digest_algo || mpi_getbyte(result, i) ) {
if( c != sig->digest_algo || mpi_getbyte(result, i) ) {
/* Padding or leading bytes in signature is wrong */
rc = G10ERR_BAD_PUBKEY;
goto leave;
@ -163,7 +216,7 @@ do_check( PKT_public_cert *pkc, PKT_signature *sig, MD_HANDLE digest )
md_putc( digest, a & 0xff );
}
md_final( digest );
dp = md_read( digest, sig->d.rsa.digest_algo );
dp = md_read( digest, sig->digest_algo );
for(i=mdlen-1; i >= 0; i--, dp++ ) {
if( mpi_getbyte( result, i ) != *dp ) {
rc = G10ERR_BAD_SIGN;
@ -188,7 +241,7 @@ do_check( PKT_public_cert *pkc, PKT_signature *sig, MD_HANDLE digest )
/****************
* check the signature pointed to by NODE. This is a key signatures.
* If the function detects a elf signature, it uses the PKC from
* If the function detects a self-signature, it uses the PKC from
* NODE and does not read the any public key.
*/
int
@ -210,9 +263,11 @@ check_key_signature( KBNODE root, KBNODE node, int *is_selfsig )
sig = node->pkt->pkt.signature;
if( sig->pubkey_algo == PUBKEY_ALGO_ELGAMAL )
algo = sig->d.elg.digest_algo;
algo = sig->digest_algo;
else if( sig->pubkey_algo == PUBKEY_ALGO_DSA )
algo = sig->digest_algo;
else if(sig->pubkey_algo == PUBKEY_ALGO_RSA )
algo = sig->d.rsa.digest_algo;
algo = sig->digest_algo;
else
return G10ERR_PUBKEY_ALGO;
if( (rc=check_digest_algo(algo)) )
@ -233,7 +288,18 @@ check_key_signature( KBNODE root, KBNODE node, int *is_selfsig )
keyid_from_pkc( pkc, keyid );
md = md_open( algo, 0 );
if( sig->sig_class== 16 )
md->debug = fopen("dsahashsig","w");
hash_public_cert( md, pkc );
if( sig->version >=4 ) {
byte buf[5];
buf[0] = 0xb4; /* indicates a userid packet */
buf[1] = uid->len >> 24; /* but use 4 length bytes */
buf[2] = uid->len >> 16;
buf[3] = uid->len >> 8;
buf[4] = uid->len;
md_write( md, buf, 5 );
}
md_write( md, uid->name, uid->len );
if( keyid[0] == sig->keyid[0] && keyid[1] == sig->keyid[1] ) {
if( is_selfsig )
@ -243,6 +309,8 @@ check_key_signature( KBNODE root, KBNODE node, int *is_selfsig )
else
rc = signature_check( sig, md );
md_close(md);
if( sig->sig_class== 16 )
fclose(md->debug);
}
else {
log_error("no user id for key signature packet\n");