static void
encrypt_seskey (DEK *dek, DEK **seskey, byte *enckey)
{
gcry_cipher_hd_t hd;
byte buf[33];
assert ( dek->keylen <= 32 );
if (!*seskey)
{
*seskey=xmalloc_clear(sizeof(DEK));
(*seskey)->keylen=dek->keylen;
(*seskey)->algo=dek->algo;
make_session_key(*seskey);
/*log_hexdump( "thekey", c->key, c->keylen );*/
}
/* The encrypted session key is prefixed with a one-octet algorithm id. */
buf[0] = (*seskey)->algo;
memcpy( buf + 1, (*seskey)->key, (*seskey)->keylen );
/* We only pass already checked values to the following fucntion,
thus we consider any failure as fatal. */
if (openpgp_cipher_open (&hd, dek->algo, GCRY_CIPHER_MODE_CFB, 1))
BUG ();
if (gcry_cipher_setkey (hd, dek->key, dek->keylen))
BUG ();
gcry_cipher_setiv (hd, NULL, 0);
gcry_cipher_encrypt (hd, buf, (*seskey)->keylen + 1, NULL, 0);
gcry_cipher_close (hd);
memcpy( enckey, buf, (*seskey)->keylen + 1 );
wipememory( buf, sizeof buf ); /* burn key */
}
/****************
* Make a session key and put it into DEK
*/
void
make_session_key( DEK *dek )
{
gcry_cipher_hd_t chd;
int i, rc;
dek->keylen = openpgp_cipher_get_algo_keylen (dek->algo);
if (openpgp_cipher_open (&chd, dek->algo, GCRY_CIPHER_MODE_CFB,
(GCRY_CIPHER_SECURE
| (dek->algo >= 100 ?
0 : GCRY_CIPHER_ENABLE_SYNC))) )
BUG();
gcry_randomize (dek->key, dek->keylen, GCRY_STRONG_RANDOM );
for (i=0; i < 16; i++ )
{
rc = gcry_cipher_setkey (chd, dek->key, dek->keylen);
if (!rc)
{
gcry_cipher_close (chd);
return;
}
if (gpg_err_code (rc) != GPG_ERR_WEAK_KEY)
BUG();
log_info(_("weak key created - retrying\n") );
/* Renew the session key until we get a non-weak key. */
gcry_randomize (dek->key, dek->keylen, GCRY_STRONG_RANDOM);
}
log_fatal (_("cannot avoid weak key for symmetric cipher; "
"tried %d times!\n"), i);
}
/****************
* Decrypt the data, specified by ED with the key DEK.
*/
int
decrypt_data( void *procctx, PKT_encrypted *ed, DEK *dek )
{
decode_filter_ctx_t dfx;
byte *p;
int rc=0, c, i;
byte temp[32];
unsigned blocksize;
unsigned nprefix;
dfx = xtrycalloc (1, sizeof *dfx);
if (!dfx)
return gpg_error_from_syserror ();
dfx->refcount = 1;
if ( opt.verbose && !dek->algo_info_printed )
{
if (!openpgp_cipher_test_algo (dek->algo))
log_info (_("%s encrypted data\n"),
openpgp_cipher_algo_name (dek->algo));
else
log_info (_("encrypted with unknown algorithm %d\n"), dek->algo );
dek->algo_info_printed = 1;
}
rc = openpgp_cipher_test_algo (dek->algo);
if (rc)
goto leave;
blocksize = openpgp_cipher_get_algo_blklen (dek->algo);
if ( !blocksize || blocksize > 16 )
log_fatal ("unsupported blocksize %u\n", blocksize );
nprefix = blocksize;
if ( ed->len && ed->len < (nprefix+2) )
BUG();
if ( ed->mdc_method )
{
if (gcry_md_open (&dfx->mdc_hash, ed->mdc_method, 0 ))
BUG ();
if ( DBG_HASHING )
gcry_md_start_debug (dfx->mdc_hash, "checkmdc");
}
rc = openpgp_cipher_open (&dfx->cipher_hd, dek->algo,
GCRY_CIPHER_MODE_CFB,
(GCRY_CIPHER_SECURE
| ((ed->mdc_method || dek->algo >= 100)?
0 : GCRY_CIPHER_ENABLE_SYNC)));
if (rc)
{
/* We should never get an error here cause we already checked
* that the algorithm is available. */
BUG();
}
/* log_hexdump( "thekey", dek->key, dek->keylen );*/
rc = gcry_cipher_setkey (dfx->cipher_hd, dek->key, dek->keylen);
if ( gpg_err_code (rc) == GPG_ERR_WEAK_KEY )
{
log_info(_("WARNING: message was encrypted with"
" a weak key in the symmetric cipher.\n"));
rc=0;
}
else if( rc )
{
log_error("key setup failed: %s\n", g10_errstr(rc) );
goto leave;
}
if (!ed->buf)
{
log_error(_("problem handling encrypted packet\n"));
goto leave;
}
gcry_cipher_setiv (dfx->cipher_hd, NULL, 0);
if ( ed->len )
{
for (i=0; i < (nprefix+2) && ed->len; i++, ed->len-- )
{
if ( (c=iobuf_get(ed->buf)) == -1 )
break;
else
temp[i] = c;
}
}
else
{
for (i=0; i < (nprefix+2); i++ )
if ( (c=iobuf_get(ed->buf)) == -1 )
break;
else
temp[i] = c;
}
gcry_cipher_decrypt (dfx->cipher_hd, temp, nprefix+2, NULL, 0);
gcry_cipher_sync (dfx->cipher_hd);
p = temp;
/* log_hexdump( "prefix", temp, nprefix+2 ); */
if (dek->symmetric
&& (p[nprefix-2] != p[nprefix] || p[nprefix-1] != p[nprefix+1]) )
{
rc = gpg_error (GPG_ERR_BAD_KEY);
goto leave;
}
if ( dfx->mdc_hash )
gcry_md_write (dfx->mdc_hash, temp, nprefix+2);
dfx->refcount++;
if ( ed->mdc_method )
iobuf_push_filter ( ed->buf, mdc_decode_filter, dfx );
else
iobuf_push_filter ( ed->buf, decode_filter, dfx );
proc_packets ( procctx, ed->buf );
ed->buf = NULL;
if ( ed->mdc_method && dfx->eof_seen == 2 )
rc = gpg_error (GPG_ERR_INV_PACKET);
else if ( ed->mdc_method )
{
/* We used to let parse-packet.c handle the MDC packet but this
turned out to be a problem with compressed packets: With old
style packets there is no length information available and
the decompressor uses an implicit end. However we can't know
this implicit end beforehand (:-) and thus may feed the
decompressor with more bytes than actually needed. It would
be possible to unread the extra bytes but due to our weird
iobuf system any unread is non reliable due to filters
already popped off. The easy and sane solution is to care
about the MDC packet only here and never pass it to the
packet parser. Fortunatley the OpenPGP spec requires a
strict format for the MDC packet so that we know that 22
bytes are appended. */
int datalen = gcry_md_get_algo_dlen (ed->mdc_method);
assert (dfx->cipher_hd);
assert (dfx->mdc_hash);
gcry_cipher_decrypt (dfx->cipher_hd, dfx->defer, 22, NULL, 0);
gcry_md_write (dfx->mdc_hash, dfx->defer, 2);
gcry_md_final (dfx->mdc_hash);
if (dfx->defer[0] != '\xd3' || dfx->defer[1] != '\x14' )
{
log_error("mdc_packet with invalid encoding\n");
rc = gpg_error (GPG_ERR_INV_PACKET);
}
else if (datalen != 20
|| memcmp (gcry_md_read (dfx->mdc_hash, 0),
dfx->defer+2,datalen ))
rc = gpg_error (GPG_ERR_BAD_SIGNATURE);
/* log_printhex("MDC message:", dfx->defer, 22); */
/* log_printhex("MDC calc:", gcry_md_read (dfx->mdc_hash,0), datalen); */
}
leave:
release_dfx_context (dfx);
return rc;
}
static int
xxxx_do_check( PKT_secret_key *sk, const char *tryagain_text, int mode,
int *canceled )
{
gpg_error_t err;
byte *buffer;
u16 csum=0;
int i, res;
size_t nbytes;
if( sk->is_protected ) { /* remove the protection */
DEK *dek = NULL;
u32 keyid[4]; /* 4! because we need two of them */
gcry_cipher_hd_t cipher_hd=NULL;
PKT_secret_key *save_sk;
if( sk->protect.s2k.mode == 1001 ) {
log_info(_("secret key parts are not available\n"));
return GPG_ERR_UNUSABLE_SECKEY;
}
if( sk->protect.algo == CIPHER_ALGO_NONE )
BUG();
if( openpgp_cipher_test_algo( sk->protect.algo ) ) {
log_info(_("protection algorithm %d%s is not supported\n"),
sk->protect.algo,sk->protect.algo==1?" (IDEA)":"" );
return GPG_ERR_CIPHER_ALGO;
}
if(gcry_md_test_algo (sk->protect.s2k.hash_algo))
{
log_info(_("protection digest %d is not supported\n"),
sk->protect.s2k.hash_algo);
return GPG_ERR_DIGEST_ALGO;
}
keyid_from_sk( sk, keyid );
keyid[2] = keyid[3] = 0;
if (!sk->flags.primary)
{
keyid[2] = sk->main_keyid[0];
keyid[3] = sk->main_keyid[1];
}
dek = passphrase_to_dek( keyid, sk->pubkey_algo, sk->protect.algo,
&sk->protect.s2k, mode,
tryagain_text, canceled );
if (!dek && canceled && *canceled)
return GPG_ERR_CANCELED;
err = openpgp_cipher_open (&cipher_hd, sk->protect.algo,
GCRY_CIPHER_MODE_CFB,
(GCRY_CIPHER_SECURE
| (sk->protect.algo >= 100 ?
0 : GCRY_CIPHER_ENABLE_SYNC)));
if (err)
log_fatal ("cipher open failed: %s\n", gpg_strerror (err) );
err = gcry_cipher_setkey (cipher_hd, dek->key, dek->keylen);
if (err)
log_fatal ("set key failed: %s\n", gpg_strerror (err) );
xfree(dek);
save_sk = copy_secret_key( NULL, sk );
gcry_cipher_setiv ( cipher_hd, sk->protect.iv, sk->protect.ivlen );
csum = 0;
if( sk->version >= 4 ) {
int ndata;
unsigned int ndatabits;
byte *p, *data;
u16 csumc = 0;
i = pubkey_get_npkey(sk->pubkey_algo);
assert ( gcry_mpi_get_flag (sk->skey[i], GCRYMPI_FLAG_OPAQUE ));
p = gcry_mpi_get_opaque ( sk->skey[i], &ndatabits );
ndata = (ndatabits+7)/8;
if ( ndata > 1 )
csumc = buf16_to_u16 (p+ndata-2);
data = xmalloc_secure ( ndata );
gcry_cipher_decrypt ( cipher_hd, data, ndata, p, ndata );
gcry_mpi_release (sk->skey[i]); sk->skey[i] = NULL ;
p = data;
if (sk->protect.sha1chk) {
/* This is the new SHA1 checksum method to detect
tampering with the key as used by the Klima/Rosa
attack */
sk->csum = 0;
csum = 1;
if( ndata < 20 )
log_error("not enough bytes for SHA-1 checksum\n");
else {
gcry_md_hd_t h;
if ( gcry_md_open (&h, DIGEST_ALGO_SHA1, 1))
BUG(); /* Algo not available. */
gcry_md_write (h, data, ndata - 20);
gcry_md_final (h);
if (!memcmp (gcry_md_read (h, DIGEST_ALGO_SHA1),
data + ndata - 20, 20) )
{
/* Digest does match. We have to keep the old
style checksum in sk->csum, so that the
test used for unprotected keys does work.
This test gets used when we are adding new
keys. */
sk->csum = csum = checksum (data, ndata-20);
}
gcry_md_close (h);
}
}
else {
if( ndata < 2 ) {
log_error("not enough bytes for checksum\n");
sk->csum = 0;
csum = 1;
}
else {
csum = checksum( data, ndata-2);
sk->csum = data[ndata-2] << 8 | data[ndata-1];
if ( sk->csum != csum ) {
/* This is a PGP 7.0.0 workaround */
sk->csum = csumc; /* take the encrypted one */
}
}
}
/* Must check it here otherwise the mpi_read_xx would fail
because the length may have an arbitrary value */
if( sk->csum == csum ) {
for( ; i < pubkey_get_nskey(sk->pubkey_algo); i++ ) {
if ( gcry_mpi_scan( &sk->skey[i], GCRYMPI_FMT_PGP,
p, ndata, &nbytes))
{
/* Checksum was okay, but not correctly
decrypted. */
sk->csum = 0;
csum = 1;
break;
}
ndata -= nbytes;
p += nbytes;
}
/* Note: at this point ndata should be 2 for a simple
checksum or 20 for the sha1 digest */
}
xfree(data);
}
else {
for(i=pubkey_get_npkey(sk->pubkey_algo);
i < pubkey_get_nskey(sk->pubkey_algo); i++ ) {
byte *p;
size_t ndata;
unsigned int ndatabits;
assert (gcry_mpi_get_flag (sk->skey[i], GCRYMPI_FLAG_OPAQUE));
p = gcry_mpi_get_opaque (sk->skey[i], &ndatabits);
ndata = (ndatabits+7)/8;
assert (ndata >= 2);
assert (ndata == ((p[0] << 8 | p[1]) + 7)/8 + 2);
buffer = xmalloc_secure (ndata);
gcry_cipher_sync (cipher_hd);
buffer[0] = p[0];
buffer[1] = p[1];
gcry_cipher_decrypt (cipher_hd, buffer+2, ndata-2,
p+2, ndata-2);
csum += checksum (buffer, ndata);
gcry_mpi_release (sk->skey[i]);
err = gcry_mpi_scan( &sk->skey[i], GCRYMPI_FMT_PGP,
buffer, ndata, &ndata );
xfree (buffer);
if (err)
{
/* Checksum was okay, but not correctly
decrypted. */
sk->csum = 0;
csum = 1;
break;
}
/* csum += checksum_mpi (sk->skey[i]); */
}
}
gcry_cipher_close ( cipher_hd );
/* Now let's see whether we have used the correct passphrase. */
if( csum != sk->csum ) {
copy_secret_key( sk, save_sk );
passphrase_clear_cache ( keyid, NULL, sk->pubkey_algo );
free_secret_key( save_sk );
return gpg_error (GPG_ERR_BAD_PASSPHRASE);
}
/* The checksum may fail, so we also check the key itself. */
res = pk_check_secret_key ( sk->pubkey_algo, sk->skey );
if( res ) {
copy_secret_key( sk, save_sk );
passphrase_clear_cache ( keyid, NULL, sk->pubkey_algo );
free_secret_key( save_sk );
return gpg_error (GPG_ERR_BAD_PASSPHRASE);
}
free_secret_key( save_sk );
sk->is_protected = 0;
}
else { /* not protected, assume it is okay if the checksum is okay */
csum = 0;
for(i=pubkey_get_npkey(sk->pubkey_algo);
i < pubkey_get_nskey(sk->pubkey_algo); i++ ) {
csum += checksum_mpi( sk->skey[i] );
}
if( csum != sk->csum )
return GPG_ERR_CHECKSUM;
}
return 0;
}
static void
write_header (cipher_filter_context_t *cfx, iobuf_t a)
{
gcry_error_t err;
PACKET pkt;
PKT_encrypted ed;
byte temp[18];
unsigned int blocksize;
unsigned int nprefix;
blocksize = openpgp_cipher_get_algo_blklen (cfx->dek->algo);
if ( blocksize < 8 || blocksize > 16 )
log_fatal ("unsupported blocksize %u\n", blocksize);
memset (&ed, 0, sizeof ed);
ed.len = cfx->datalen;
ed.extralen = blocksize + 2;
ed.new_ctb = !ed.len;
if (cfx->dek->use_mdc)
{
ed.mdc_method = DIGEST_ALGO_SHA1;
gcry_md_open (&cfx->mdc_hash, DIGEST_ALGO_SHA1, 0);
if (DBG_HASHING)
gcry_md_debug (cfx->mdc_hash, "creatmdc");
}
else if (!opt.no_mdc_warn)
{
log_info ("WARNING: "
"encrypting without integrity protection is dangerous\n");
}
write_status_printf (STATUS_BEGIN_ENCRYPTION, "%d %d",
ed.mdc_method, cfx->dek->algo);
init_packet (&pkt);
pkt.pkttype = cfx->dek->use_mdc? PKT_ENCRYPTED_MDC : PKT_ENCRYPTED;
pkt.pkt.encrypted = &ed;
if (build_packet( a, &pkt))
log_bug ("build_packet(ENCR_DATA) failed\n");
nprefix = blocksize;
gcry_randomize (temp, nprefix, GCRY_STRONG_RANDOM );
temp[nprefix] = temp[nprefix-2];
temp[nprefix+1] = temp[nprefix-1];
print_cipher_algo_note (cfx->dek->algo);
err = openpgp_cipher_open (&cfx->cipher_hd,
cfx->dek->algo,
GCRY_CIPHER_MODE_CFB,
(GCRY_CIPHER_SECURE
| ((cfx->dek->use_mdc || cfx->dek->algo >= 100)?
0 : GCRY_CIPHER_ENABLE_SYNC)));
if (err)
{
/* We should never get an error here cause we already checked,
* that the algorithm is available. */
BUG();
}
/* log_hexdump ("thekey", cfx->dek->key, cfx->dek->keylen); */
gcry_cipher_setkey (cfx->cipher_hd, cfx->dek->key, cfx->dek->keylen);
gcry_cipher_setiv (cfx->cipher_hd, NULL, 0);
/* log_hexdump ("prefix", temp, nprefix+2); */
if (cfx->mdc_hash) /* Hash the "IV". */
gcry_md_write (cfx->mdc_hash, temp, nprefix+2 );
gcry_cipher_encrypt (cfx->cipher_hd, temp, nprefix+2, NULL, 0);
gcry_cipher_sync (cfx->cipher_hd);
iobuf_write (a, temp, nprefix+2);
cfx->short_blklen_warn = (blocksize < 16);
cfx->short_blklen_count = nprefix+2;
cfx->wrote_header = 1;
}
/****************
* Decrypt the data, specified by ED with the key DEK.
*/
int
decrypt_data (ctrl_t ctrl, void *procctx, PKT_encrypted *ed, DEK *dek)
{
decode_filter_ctx_t dfx;
byte *p;
int rc=0, c, i;
byte temp[32];
unsigned blocksize;
unsigned nprefix;
dfx = xtrycalloc (1, sizeof *dfx);
if (!dfx)
return gpg_error_from_syserror ();
dfx->refcount = 1;
if ( opt.verbose && !dek->algo_info_printed )
{
if (!openpgp_cipher_test_algo (dek->algo))
log_info (_("%s encrypted data\n"),
openpgp_cipher_algo_name (dek->algo));
else
log_info (_("encrypted with unknown algorithm %d\n"), dek->algo );
dek->algo_info_printed = 1;
}
{
char buf[20];
snprintf (buf, sizeof buf, "%d %d", ed->mdc_method, dek->algo);
write_status_text (STATUS_DECRYPTION_INFO, buf);
}
if (opt.show_session_key)
{
char numbuf[25];
char *hexbuf;
snprintf (numbuf, sizeof numbuf, "%d:", dek->algo);
hexbuf = bin2hex (dek->key, dek->keylen, NULL);
if (!hexbuf)
{
rc = gpg_error_from_syserror ();
goto leave;
}
log_info ("session key: '%s%s'\n", numbuf, hexbuf);
write_status_strings (STATUS_SESSION_KEY, numbuf, hexbuf, NULL);
xfree (hexbuf);
}
rc = openpgp_cipher_test_algo (dek->algo);
if (rc)
goto leave;
blocksize = openpgp_cipher_get_algo_blklen (dek->algo);
if ( !blocksize || blocksize > 16 )
log_fatal ("unsupported blocksize %u\n", blocksize );
nprefix = blocksize;
if ( ed->len && ed->len < (nprefix+2) )
{
/* An invalid message. We can't check that during parsing
because we may not know the used cipher then. */
rc = gpg_error (GPG_ERR_INV_PACKET);
goto leave;
}
if ( ed->mdc_method )
{
if (gcry_md_open (&dfx->mdc_hash, ed->mdc_method, 0 ))
BUG ();
if ( DBG_HASHING )
gcry_md_debug (dfx->mdc_hash, "checkmdc");
}
rc = openpgp_cipher_open (&dfx->cipher_hd, dek->algo,
GCRY_CIPHER_MODE_CFB,
(GCRY_CIPHER_SECURE
| ((ed->mdc_method || dek->algo >= 100)?
0 : GCRY_CIPHER_ENABLE_SYNC)));
if (rc)
{
/* We should never get an error here cause we already checked
* that the algorithm is available. */
BUG();
}
/* log_hexdump( "thekey", dek->key, dek->keylen );*/
rc = gcry_cipher_setkey (dfx->cipher_hd, dek->key, dek->keylen);
if ( gpg_err_code (rc) == GPG_ERR_WEAK_KEY )
{
log_info(_("WARNING: message was encrypted with"
" a weak key in the symmetric cipher.\n"));
rc=0;
}
else if( rc )
{
log_error("key setup failed: %s\n", gpg_strerror (rc) );
goto leave;
}
if (!ed->buf)
{
log_error(_("problem handling encrypted packet\n"));
goto leave;
}
gcry_cipher_setiv (dfx->cipher_hd, NULL, 0);
if ( ed->len )
{
for (i=0; i < (nprefix+2) && ed->len; i++, ed->len-- )
{
if ( (c=iobuf_get(ed->buf)) == -1 )
break;
else
temp[i] = c;
}
}
else
{
for (i=0; i < (nprefix+2); i++ )
if ( (c=iobuf_get(ed->buf)) == -1 )
break;
else
temp[i] = c;
}
gcry_cipher_decrypt (dfx->cipher_hd, temp, nprefix+2, NULL, 0);
gcry_cipher_sync (dfx->cipher_hd);
p = temp;
/* log_hexdump( "prefix", temp, nprefix+2 ); */
if (dek->symmetric
&& (p[nprefix-2] != p[nprefix] || p[nprefix-1] != p[nprefix+1]) )
{
rc = gpg_error (GPG_ERR_BAD_KEY);
goto leave;
}
if ( dfx->mdc_hash )
gcry_md_write (dfx->mdc_hash, temp, nprefix+2);
dfx->refcount++;
dfx->partial = ed->is_partial;
dfx->length = ed->len;
if ( ed->mdc_method )
iobuf_push_filter ( ed->buf, mdc_decode_filter, dfx );
else
iobuf_push_filter ( ed->buf, decode_filter, dfx );
if (opt.unwrap_encryption)
{
char *filename;
estream_t fp;
rc = get_output_file ("", 0, ed->buf, &filename, &fp);
if (! rc)
{
iobuf_t output = iobuf_esopen (fp, "w", 0);
armor_filter_context_t *afx = NULL;
if (opt.armor)
{
afx = new_armor_context ();
push_armor_filter (afx, output);
}
iobuf_copy (output, ed->buf);
if ((rc = iobuf_error (ed->buf)))
log_error (_("error reading '%s': %s\n"),
filename, gpg_strerror (rc));
else if ((rc = iobuf_error (output)))
log_error (_("error writing '%s': %s\n"),
filename, gpg_strerror (rc));
iobuf_close (output);
if (afx)
release_armor_context (afx);
}
}
else
proc_packets (ctrl, procctx, ed->buf );
ed->buf = NULL;
if (dfx->eof_seen > 1 )
rc = gpg_error (GPG_ERR_INV_PACKET);
else if ( ed->mdc_method )
{
/* We used to let parse-packet.c handle the MDC packet but this
turned out to be a problem with compressed packets: With old
style packets there is no length information available and
the decompressor uses an implicit end. However we can't know
this implicit end beforehand (:-) and thus may feed the
decompressor with more bytes than actually needed. It would
be possible to unread the extra bytes but due to our weird
iobuf system any unread is non reliable due to filters
already popped off. The easy and sane solution is to care
about the MDC packet only here and never pass it to the
packet parser. Fortunatley the OpenPGP spec requires a
strict format for the MDC packet so that we know that 22
bytes are appended. */
int datalen = gcry_md_get_algo_dlen (ed->mdc_method);
log_assert (dfx->cipher_hd);
log_assert (dfx->mdc_hash);
gcry_cipher_decrypt (dfx->cipher_hd, dfx->defer, 22, NULL, 0);
gcry_md_write (dfx->mdc_hash, dfx->defer, 2);
gcry_md_final (dfx->mdc_hash);
if ( dfx->defer[0] != '\xd3'
|| dfx->defer[1] != '\x14'
|| datalen != 20
|| memcmp (gcry_md_read (dfx->mdc_hash, 0), dfx->defer+2, datalen))
rc = gpg_error (GPG_ERR_BAD_SIGNATURE);
/* log_printhex("MDC message:", dfx->defer, 22); */
/* log_printhex("MDC calc:", gcry_md_read (dfx->mdc_hash,0), datalen); */
}
leave:
release_dfx_context (dfx);
return rc;
}
/* Encrypt a session key using DEK and store a pointer to the result
* at R_ENCKEY and its length at R_ENCKEYLEN.
*
* R_SESKEY points to the unencrypted session key (.KEY, .KEYLEN) and
* the algorithm that will be used to encrypt the contents of the
* SKESK packet (.ALGO). If R_SESKEY points to NULL, then a random
* session key that is appropriate for DEK->ALGO is generated and
* stored at R_SESKEY. If AEAD_ALGO is not 0 the given AEAD algorithm
* is used for encryption.
*/
gpg_error_t
encrypt_seskey (DEK *dek, aead_algo_t aead_algo,
DEK **r_seskey, void **r_enckey, size_t *r_enckeylen)
{
gpg_error_t err;
gcry_cipher_hd_t hd = NULL;
byte *buf = NULL;
DEK *seskey;
*r_enckey = NULL;
*r_enckeylen = 0;
if (*r_seskey)
seskey = *r_seskey;
else
{
seskey = xtrycalloc (1, sizeof(DEK));
if (!seskey)
{
err = gpg_error_from_syserror ();
goto leave;
}
seskey->algo = dek->algo;
make_session_key (seskey);
/*log_hexdump( "thekey", c->key, c->keylen );*/
}
if (aead_algo)
{
unsigned int noncelen;
enum gcry_cipher_modes ciphermode;
byte ad[4];
err = openpgp_aead_algo_info (aead_algo, &ciphermode, &noncelen);
if (err)
goto leave;
/* Allocate space for the nonce, the key, and the authentication
* tag (16). */
buf = xtrymalloc_secure (noncelen + seskey->keylen + 16);
if (!buf)
{
err = gpg_error_from_syserror ();
goto leave;
}
gcry_randomize (buf, noncelen, GCRY_STRONG_RANDOM);
err = openpgp_cipher_open (&hd, dek->algo,
ciphermode, GCRY_CIPHER_SECURE);
if (!err)
err = gcry_cipher_setkey (hd, dek->key, dek->keylen);
if (!err)
err = gcry_cipher_setiv (hd, buf, noncelen);
if (err)
goto leave;
ad[0] = (0xc0 | PKT_SYMKEY_ENC);
ad[1] = 5;
ad[2] = dek->algo;
ad[3] = aead_algo;
err = gcry_cipher_authenticate (hd, ad, 4);
if (err)
goto leave;
memcpy (buf + noncelen, seskey->key, seskey->keylen);
gcry_cipher_final (hd);
err = gcry_cipher_encrypt (hd, buf + noncelen, seskey->keylen, NULL,0);
if (err)
goto leave;
err = gcry_cipher_gettag (hd, buf + noncelen + seskey->keylen, 16);
if (err)
goto leave;
*r_enckeylen = noncelen + seskey->keylen + 16;
*r_enckey = buf;
buf = NULL;
}
else
{
/* In the old version 4 SKESK the encrypted session key is
* prefixed with a one-octet algorithm id. */
buf = xtrymalloc_secure (1 + seskey->keylen);
if (!buf)
{
err = gpg_error_from_syserror ();
goto leave;
}
buf[0] = seskey->algo;
memcpy (buf + 1, seskey->key, seskey->keylen);
err = openpgp_cipher_open (&hd, dek->algo, GCRY_CIPHER_MODE_CFB, 1);
if (!err)
err = gcry_cipher_setkey (hd, dek->key, dek->keylen);
if (!err)
err = gcry_cipher_setiv (hd, NULL, 0);
if (!err)
err = gcry_cipher_encrypt (hd, buf, seskey->keylen + 1, NULL, 0);
if (err)
goto leave;
*r_enckeylen = seskey->keylen + 1;
*r_enckey = buf;
buf = NULL;
}
/* Return the session key in case we allocated it. */
*r_seskey = seskey;
seskey = NULL;
leave:
gcry_cipher_close (hd);
if (seskey != *r_seskey)
xfree (seskey);
xfree (buf);
return err;
}
/****************
* Protect the secret key with the passphrase from DEK
*/
int
protect_secret_key( PKT_secret_key *sk, DEK *dek )
{
int i,j, rc = 0;
byte *buffer;
size_t nbytes;
u16 csum;
if( !dek )
return 0;
if( !sk->is_protected ) { /* okay, apply the protection */
gcry_cipher_hd_t cipher_hd=NULL;
if ( openpgp_cipher_test_algo ( sk->protect.algo ) ) {
/* Unsupport protection algorithm. */
rc = gpg_error (GPG_ERR_CIPHER_ALGO);
}
else {
print_cipher_algo_note( sk->protect.algo );
if ( openpgp_cipher_open (&cipher_hd, sk->protect.algo,
GCRY_CIPHER_MODE_CFB,
(GCRY_CIPHER_SECURE
| (sk->protect.algo >= 100 ?
0 : GCRY_CIPHER_ENABLE_SYNC))) )
BUG();
if ( gcry_cipher_setkey ( cipher_hd, dek->key, dek->keylen ) )
log_info(_("WARNING: Weak key detected"
" - please change passphrase again.\n"));
sk->protect.ivlen = openpgp_cipher_get_algo_blklen (sk->protect.algo);
assert( sk->protect.ivlen <= DIM(sk->protect.iv) );
if( sk->protect.ivlen != 8 && sk->protect.ivlen != 16 )
BUG(); /* yes, we are very careful */
gcry_create_nonce (sk->protect.iv, sk->protect.ivlen);
gcry_cipher_setiv (cipher_hd, sk->protect.iv, sk->protect.ivlen);
if( sk->version >= 4 ) {
byte *bufarr[PUBKEY_MAX_NSKEY];
size_t narr[PUBKEY_MAX_NSKEY];
unsigned int nbits[PUBKEY_MAX_NSKEY];
int ndata=0;
byte *p, *data;
for (j=0, i = pubkey_get_npkey(sk->pubkey_algo);
i < pubkey_get_nskey(sk->pubkey_algo); i++, j++ )
{
assert (!gcry_mpi_get_flag (sk->skey[i],
GCRYMPI_FLAG_OPAQUE));
if (gcry_mpi_aprint (GCRYMPI_FMT_USG, bufarr+j,
narr+j, sk->skey[i]))
BUG();
nbits[j] = gcry_mpi_get_nbits (sk->skey[i]);
ndata += narr[j] + 2;
}
for ( ; j < PUBKEY_MAX_NSKEY; j++ )
bufarr[j] = NULL;
ndata += opt.simple_sk_checksum? 2 : 20; /* for checksum */
data = xmalloc_secure( ndata );
p = data;
for(j=0; j < PUBKEY_MAX_NSKEY && bufarr[j]; j++ ) {
p[0] = nbits[j] >> 8 ;
p[1] = nbits[j];
p += 2;
memcpy(p, bufarr[j], narr[j] );
p += narr[j];
xfree(bufarr[j]);
}
if (opt.simple_sk_checksum) {
log_info (_("generating the deprecated 16-bit checksum"
" for secret key protection\n"));
csum = checksum( data, ndata-2);
sk->csum = csum;
*p++ = csum >> 8;
*p++ = csum;
sk->protect.sha1chk = 0;
}
else {
