mirror of git://git.gnupg.org/gnupg.git
Werner Koch
parent
9f641430dc
commit
067e62fe55
210
g10/cipher.c
210
g10/cipher.c
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@ -1,6 +1,6 @@
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/* cipher.c - En-/De-ciphering filter
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* Copyright (C) 1998, 1999, 2000, 2001, 2003,
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* 2006, 2009 Free Software Foundation, Inc.
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* Copyright (C) 1998-2003, 2006, 2009 Free Software Foundation, Inc.
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* Copyright (C) 1998-2003, 2006, 2009, 2017 Werner koch
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*
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* This file is part of GnuPG.
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*
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@ -16,6 +16,7 @@
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, see <https://www.gnu.org/licenses/>.
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* SPDX-License-Identifier: GPL-3.0+
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*/
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#include <config.h>
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@ -39,124 +40,129 @@
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static void
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write_header( cipher_filter_context_t *cfx, IOBUF a )
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write_header (cipher_filter_context_t *cfx, iobuf_t a)
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{
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gcry_error_t err;
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PACKET pkt;
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PKT_encrypted ed;
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byte temp[18];
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unsigned int blocksize;
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unsigned int nprefix;
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gcry_error_t err;
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PACKET pkt;
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PKT_encrypted ed;
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byte temp[18];
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unsigned int blocksize;
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unsigned int nprefix;
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blocksize = openpgp_cipher_get_algo_blklen (cfx->dek->algo);
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if ( blocksize < 8 || blocksize > 16 )
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log_fatal("unsupported blocksize %u\n", blocksize );
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memset( &ed, 0, sizeof ed );
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ed.len = cfx->datalen;
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ed.extralen = blocksize+2;
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ed.new_ctb = !ed.len;
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if( cfx->dek->use_mdc ) {
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ed.mdc_method = DIGEST_ALGO_SHA1;
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gcry_md_open (&cfx->mdc_hash, DIGEST_ALGO_SHA1, 0);
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if ( DBG_HASHING )
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gcry_md_debug (cfx->mdc_hash, "creatmdc");
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}
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blocksize = openpgp_cipher_get_algo_blklen (cfx->dek->algo);
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if ( blocksize < 8 || blocksize > 16 )
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log_fatal ("unsupported blocksize %u\n", blocksize);
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memset (&ed, 0, sizeof ed);
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ed.len = cfx->datalen;
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ed.extralen = blocksize + 2;
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ed.new_ctb = !ed.len;
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if (cfx->dek->use_mdc)
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{
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char buf[20];
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sprintf (buf, "%d %d", ed.mdc_method, cfx->dek->algo);
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write_status_text (STATUS_BEGIN_ENCRYPTION, buf);
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ed.mdc_method = DIGEST_ALGO_SHA1;
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gcry_md_open (&cfx->mdc_hash, DIGEST_ALGO_SHA1, 0);
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if (DBG_HASHING)
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gcry_md_debug (cfx->mdc_hash, "creatmdc");
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}
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init_packet( &pkt );
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pkt.pkttype = cfx->dek->use_mdc? PKT_ENCRYPTED_MDC : PKT_ENCRYPTED;
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pkt.pkt.encrypted = &ed;
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if( build_packet( a, &pkt ))
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log_bug("build_packet(ENCR_DATA) failed\n");
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nprefix = blocksize;
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gcry_randomize (temp, nprefix, GCRY_STRONG_RANDOM );
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temp[nprefix] = temp[nprefix-2];
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temp[nprefix+1] = temp[nprefix-1];
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print_cipher_algo_note( cfx->dek->algo );
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err = openpgp_cipher_open (&cfx->cipher_hd,
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cfx->dek->algo,
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GCRY_CIPHER_MODE_CFB,
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(GCRY_CIPHER_SECURE
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| ((cfx->dek->use_mdc || cfx->dek->algo >= 100)?
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0 : GCRY_CIPHER_ENABLE_SYNC)));
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if (err) {
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/* We should never get an error here cause we already checked,
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* that the algorithm is available. */
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BUG();
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{
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char buf[20];
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snprintf (buf, sizeof buf, "%d %d", ed.mdc_method, cfx->dek->algo);
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write_status_text (STATUS_BEGIN_ENCRYPTION, buf);
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}
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init_packet (&pkt);
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pkt.pkttype = cfx->dek->use_mdc? PKT_ENCRYPTED_MDC : PKT_ENCRYPTED;
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pkt.pkt.encrypted = &ed;
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if (build_packet( a, &pkt))
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log_bug ("build_packet(ENCR_DATA) failed\n");
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nprefix = blocksize;
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gcry_randomize (temp, nprefix, GCRY_STRONG_RANDOM );
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temp[nprefix] = temp[nprefix-2];
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temp[nprefix+1] = temp[nprefix-1];
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print_cipher_algo_note (cfx->dek->algo);
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err = openpgp_cipher_open (&cfx->cipher_hd,
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cfx->dek->algo,
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GCRY_CIPHER_MODE_CFB,
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(GCRY_CIPHER_SECURE
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| ((cfx->dek->use_mdc || cfx->dek->algo >= 100)?
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0 : GCRY_CIPHER_ENABLE_SYNC)));
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if (err)
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{
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/* We should never get an error here cause we already checked,
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* that the algorithm is available. */
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BUG();
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}
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/* log_hexdump( "thekey", cfx->dek->key, cfx->dek->keylen );*/
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gcry_cipher_setkey( cfx->cipher_hd, cfx->dek->key, cfx->dek->keylen );
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gcry_cipher_setiv( cfx->cipher_hd, NULL, 0 );
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/* log_hexdump( "prefix", temp, nprefix+2 ); */
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if (cfx->mdc_hash) /* Hash the "IV". */
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gcry_md_write (cfx->mdc_hash, temp, nprefix+2 );
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gcry_cipher_encrypt (cfx->cipher_hd, temp, nprefix+2, NULL, 0);
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gcry_cipher_sync (cfx->cipher_hd);
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iobuf_write(a, temp, nprefix+2);
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cfx->header=1;
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/* log_hexdump ("thekey", cfx->dek->key, cfx->dek->keylen); */
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gcry_cipher_setkey (cfx->cipher_hd, cfx->dek->key, cfx->dek->keylen);
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gcry_cipher_setiv (cfx->cipher_hd, NULL, 0);
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/* log_hexdump ("prefix", temp, nprefix+2); */
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if (cfx->mdc_hash) /* Hash the "IV". */
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gcry_md_write (cfx->mdc_hash, temp, nprefix+2 );
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gcry_cipher_encrypt (cfx->cipher_hd, temp, nprefix+2, NULL, 0);
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gcry_cipher_sync (cfx->cipher_hd);
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iobuf_write (a, temp, nprefix+2);
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cfx->header = 1;
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}
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/****************
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* This filter is used to en/de-cipher data with a conventional algorithm
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/*
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* This filter is used to en/de-cipher data with a symmetric algorithm
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*/
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int
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cipher_filter( void *opaque, int control,
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IOBUF a, byte *buf, size_t *ret_len)
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cipher_filter (void *opaque, int control, iobuf_t a, byte *buf, size_t *ret_len)
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{
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size_t size = *ret_len;
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cipher_filter_context_t *cfx = opaque;
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int rc=0;
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cipher_filter_context_t *cfx = opaque;
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size_t size = *ret_len;
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int rc = 0;
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if( control == IOBUFCTRL_UNDERFLOW ) { /* decrypt */
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rc = -1; /* not yet used */
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if (control == IOBUFCTRL_UNDERFLOW) /* decrypt */
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{
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rc = -1; /* not yet used */
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}
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else if( control == IOBUFCTRL_FLUSH ) { /* encrypt */
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log_assert(a);
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if( !cfx->header ) {
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write_header( cfx, a );
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else if (control == IOBUFCTRL_FLUSH) /* encrypt */
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{
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log_assert (a);
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if (!cfx->header)
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write_header (cfx, a);
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if (cfx->mdc_hash)
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gcry_md_write (cfx->mdc_hash, buf, size);
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gcry_cipher_encrypt (cfx->cipher_hd, buf, size, NULL, 0);
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rc = iobuf_write (a, buf, size);
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}
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else if (control == IOBUFCTRL_FREE)
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{
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if (cfx->mdc_hash)
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{
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byte *hash;
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int hashlen = gcry_md_get_algo_dlen (gcry_md_get_algo(cfx->mdc_hash));
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byte temp[22];
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log_assert (hashlen == 20);
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/* We must hash the prefix of the MDC packet here. */
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temp[0] = 0xd3;
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temp[1] = 0x14;
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gcry_md_putc (cfx->mdc_hash, temp[0]);
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gcry_md_putc (cfx->mdc_hash, temp[1]);
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gcry_md_final (cfx->mdc_hash);
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hash = gcry_md_read (cfx->mdc_hash, 0);
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memcpy(temp+2, hash, 20);
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gcry_cipher_encrypt (cfx->cipher_hd, temp, 22, NULL, 0);
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gcry_md_close (cfx->mdc_hash); cfx->mdc_hash = NULL;
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if (iobuf_write( a, temp, 22))
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log_error ("writing MDC packet failed\n");
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}
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if (cfx->mdc_hash)
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gcry_md_write (cfx->mdc_hash, buf, size);
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gcry_cipher_encrypt (cfx->cipher_hd, buf, size, NULL, 0);
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rc = iobuf_write( a, buf, size );
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}
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else if( control == IOBUFCTRL_FREE ) {
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if( cfx->mdc_hash ) {
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byte *hash;
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int hashlen = gcry_md_get_algo_dlen (gcry_md_get_algo
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(cfx->mdc_hash));
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byte temp[22];
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log_assert( hashlen == 20 );
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/* We must hash the prefix of the MDC packet here. */
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temp[0] = 0xd3;
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temp[1] = 0x14;
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gcry_md_putc (cfx->mdc_hash, temp[0]);
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gcry_md_putc (cfx->mdc_hash, temp[1]);
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gcry_cipher_close (cfx->cipher_hd);
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}
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else if (control == IOBUFCTRL_DESC)
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{
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mem2str (buf, "cipher_filter", *ret_len);
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}
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gcry_md_final (cfx->mdc_hash);
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hash = gcry_md_read (cfx->mdc_hash, 0);
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memcpy(temp+2, hash, 20);
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gcry_cipher_encrypt (cfx->cipher_hd, temp, 22, NULL, 0);
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gcry_md_close (cfx->mdc_hash); cfx->mdc_hash = NULL;
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if( iobuf_write( a, temp, 22 ) )
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log_error("writing MDC packet failed\n" );
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}
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gcry_cipher_close (cfx->cipher_hd);
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}
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else if( control == IOBUFCTRL_DESC ) {
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mem2str (buf, "cipher_filter", *ret_len);
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}
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return rc;
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return rc;
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}
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