int main(int argc, char **argv) { gcry_control(GCRYCTL_INITIALIZATION_FINISHED, 0); int l; int ret; armor_filter_context_t *afx = NULL; while (fgets(passphrase, N, stdin) != NULL && status == 0) { IOBUF a; struct stat sb; unlink("output"); l = strlen(passphrase); passphrase[l - 1] = 0; status = 1; a = iobuf_open(argv[1]); if( use_armor_filter( a ) ) { afx = new_armor_context (); push_armor_filter (afx, a); } proc_packets(NULL, a); ret = stat("output", &sb); if (status == 1 && sb.st_size > 0 && ret != -1) { printf("Found Password : %s\n", passphrase); exit(0); } else { status = 0; } iobuf_close(a); } return -1; }
/**************** * Handle a compressed packet */ int handle_compressed( void *procctx, PKT_compressed *cd, int (*callback)(IOBUF, void *), void *passthru ) { compress_filter_context_t *cfx; int rc; if( cd->algorithm < 1 || cd->algorithm > 2 ) return G10ERR_COMPR_ALGO; cfx = m_alloc_clear (sizeof *cfx); cfx->algo = cd->algorithm; cfx->release = release_context; iobuf_push_filter( cd->buf, compress_filter, cfx ); if( callback ) rc = callback(cd->buf, passthru ); else rc = proc_packets(procctx, cd->buf); cd->buf = NULL; return rc; }
/**************** * 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; }
/**************** * 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; }