diff options
Diffstat (limited to 'g10/sig-check.c')
| -rw-r--r-- | g10/sig-check.c | 88 |
1 files changed, 78 insertions, 10 deletions
diff --git a/g10/sig-check.c b/g10/sig-check.c index 32371b359..f25f2e19f 100644 --- a/g10/sig-check.c +++ b/g10/sig-check.c @@ -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"); |