diff --git a/g10/encrypt.c b/g10/encrypt.c index c63ec8838..c7982d448 100644 --- a/g10/encrypt.c +++ b/g10/encrypt.c @@ -1,1065 +1,1061 @@ /* encrypt.c - Main encryption driver * Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, * 2006, 2009 Free Software Foundation, Inc. * Copyright (C) 2016 g10 Code GmbH * * This file is part of GnuPG. * * GnuPG is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 3 of the License, or * (at your option) any later version. * * GnuPG is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, see . */ #include #include #include #include #include #include "gpg.h" #include "options.h" #include "packet.h" #include "../common/status.h" #include "../common/iobuf.h" #include "keydb.h" #include "../common/util.h" #include "main.h" #include "filter.h" #include "trustdb.h" #include "../common/i18n.h" #include "../common/status.h" #include "pkglue.h" #include "../common/compliance.h" static int encrypt_simple( const char *filename, int mode, int use_seskey ); static int write_pubkey_enc_from_list (ctrl_t ctrl, PK_LIST pk_list, DEK *dek, iobuf_t out); /**************** * Encrypt FILENAME with only the symmetric cipher. Take input from * stdin if FILENAME is NULL. */ int encrypt_symmetric (const char *filename) { return encrypt_simple( filename, 1, 0 ); } /**************** * Encrypt FILENAME as a literal data packet only. Take input from * stdin if FILENAME is NULL. */ int encrypt_store (const char *filename) { return encrypt_simple( filename, 0, 0 ); } /* *SESKEY contains the unencrypted session key ((*SESKEY)->KEY) and the algorithm that will be used to encrypt the contents of the SED packet ((*SESKEY)->ALGO). If *SESKEY is NULL, then a random session key that is appropriate for DEK->ALGO is generated and stored there. Encrypt that session key using DEK and store the result in ENCKEY, which must be large enough to hold (*SESKEY)->KEYLEN + 1 bytes. */ void encrypt_seskey (DEK *dek, DEK **seskey, byte *enckey) { gcry_cipher_hd_t hd; byte buf[33]; log_assert ( dek->keylen <= 32 ); if (!*seskey) { *seskey=xmalloc_clear(sizeof(DEK)); (*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 function, 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 */ } /* We try very hard to use a MDC */ int use_mdc (pk_list_t pk_list,int algo) { /* RFC-2440 don't has MDC */ if (RFC2440) return 0; /* --force-mdc overrides --disable-mdc */ if(opt.force_mdc) return 1; if(opt.disable_mdc) return 0; /* Do the keys really support MDC? */ if(select_mdc_from_pklist(pk_list)) return 1; /* The keys don't support MDC, so now we do a bit of a hack - if any of the AESes or TWOFISH are in the prefs, we assume that the user can handle a MDC. This is valid for PGP 7, which can handle MDCs though it will not generate them. 2440bis allows this, by the way. */ if(select_algo_from_prefs(pk_list,PREFTYPE_SYM, CIPHER_ALGO_AES,NULL)==CIPHER_ALGO_AES) return 1; if(select_algo_from_prefs(pk_list,PREFTYPE_SYM, CIPHER_ALGO_AES192,NULL)==CIPHER_ALGO_AES192) return 1; if(select_algo_from_prefs(pk_list,PREFTYPE_SYM, CIPHER_ALGO_AES256,NULL)==CIPHER_ALGO_AES256) return 1; if(select_algo_from_prefs(pk_list,PREFTYPE_SYM, CIPHER_ALGO_TWOFISH,NULL)==CIPHER_ALGO_TWOFISH) return 1; /* Last try. Use MDC for the modern ciphers. */ if (openpgp_cipher_get_algo_blklen (algo) != 8) return 1; if (opt.verbose) warn_missing_mdc_from_pklist (pk_list); return 0; /* No MDC */ } /* We don't want to use use_seskey yet because older gnupg versions can't handle it, and there isn't really any point unless we're making a message that can be decrypted by a public key or passphrase. */ static int encrypt_simple (const char *filename, int mode, int use_seskey) { iobuf_t inp, out; PACKET pkt; PKT_plaintext *pt = NULL; STRING2KEY *s2k = NULL; byte enckey[33]; int rc = 0; int seskeylen = 0; u32 filesize; cipher_filter_context_t cfx; armor_filter_context_t *afx = NULL; compress_filter_context_t zfx; text_filter_context_t tfx; progress_filter_context_t *pfx; int do_compress = !!default_compress_algo(); if (!gnupg_rng_is_compliant (opt.compliance)) { rc = gpg_error (GPG_ERR_FORBIDDEN); log_error (_("%s is not compliant with %s mode\n"), "RNG", gnupg_compliance_option_string (opt.compliance)); write_status_error ("random-compliance", rc); return rc; } pfx = new_progress_context (); memset( &cfx, 0, sizeof cfx); memset( &zfx, 0, sizeof zfx); memset( &tfx, 0, sizeof tfx); init_packet(&pkt); /* Prepare iobufs. */ inp = iobuf_open(filename); if (inp) iobuf_ioctl (inp, IOBUF_IOCTL_NO_CACHE, 1, NULL); if (inp && is_secured_file (iobuf_get_fd (inp))) { iobuf_close (inp); inp = NULL; gpg_err_set_errno (EPERM); } if (!inp) { rc = gpg_error_from_syserror (); log_error(_("can't open '%s': %s\n"), filename? filename: "[stdin]", strerror(errno) ); release_progress_context (pfx); return rc; } handle_progress (pfx, inp, filename); if (opt.textmode) iobuf_push_filter( inp, text_filter, &tfx ); cfx.dek = NULL; if ( mode ) { int canceled; s2k = xmalloc_clear( sizeof *s2k ); s2k->mode = opt.s2k_mode; s2k->hash_algo = S2K_DIGEST_ALGO; cfx.dek = passphrase_to_dek (default_cipher_algo (), s2k, 1, 0, NULL, &canceled); if ( !cfx.dek || !cfx.dek->keylen ) { rc = gpg_error (canceled? GPG_ERR_CANCELED:GPG_ERR_INV_PASSPHRASE); xfree (cfx.dek); xfree (s2k); iobuf_close (inp); log_error (_("error creating passphrase: %s\n"), gpg_strerror (rc)); release_progress_context (pfx); return rc; } if (use_seskey && s2k->mode != 1 && s2k->mode != 3) { use_seskey = 0; log_info (_("can't use a symmetric ESK packet " "due to the S2K mode\n")); } if ( use_seskey ) { DEK *dek = NULL; seskeylen = openpgp_cipher_get_algo_keylen (default_cipher_algo ()); encrypt_seskey( cfx.dek, &dek, enckey ); xfree( cfx.dek ); cfx.dek = dek; } if (opt.verbose) log_info(_("using cipher %s\n"), openpgp_cipher_algo_name (cfx.dek->algo)); cfx.dek->use_mdc=use_mdc(NULL,cfx.dek->algo); } if (do_compress && cfx.dek && cfx.dek->use_mdc && is_file_compressed(filename, &rc)) { if (opt.verbose) log_info(_("'%s' already compressed\n"), filename); do_compress = 0; } if ( rc || (rc = open_outfile (-1, filename, opt.armor? 1:0, 0, &out ))) { iobuf_cancel (inp); xfree (cfx.dek); xfree (s2k); release_progress_context (pfx); return rc; } if ( opt.armor ) { afx = new_armor_context (); push_armor_filter (afx, out); } if ( s2k ) { PKT_symkey_enc *enc = xmalloc_clear( sizeof *enc + seskeylen + 1 ); enc->version = 4; enc->cipher_algo = cfx.dek->algo; enc->s2k = *s2k; if ( use_seskey && seskeylen ) { enc->seskeylen = seskeylen + 1; /* algo id */ memcpy (enc->seskey, enckey, seskeylen + 1 ); } pkt.pkttype = PKT_SYMKEY_ENC; pkt.pkt.symkey_enc = enc; if ((rc = build_packet( out, &pkt ))) log_error("build symkey packet failed: %s\n", gpg_strerror (rc) ); xfree (enc); } if (!opt.no_literal) pt = setup_plaintext_name (filename, inp); /* Note that PGP 5 has problems decrypting symmetrically encrypted data if the file length is in the inner packet. It works when only partial length headers are use. In the past, we always used partial body length here, but since PGP 2, PGP 6, and PGP 7 need the file length, and nobody should be using PGP 5 nowadays anyway, this is now set to the file length. Note also that this only applies to the RFC-1991 style symmetric messages, and not the RFC-2440 style. PGP 6 and 7 work with either partial length or fixed length with the new style messages. */ if ( !iobuf_is_pipe_filename (filename) && *filename && !opt.textmode ) { off_t tmpsize; int overflow; if ( !(tmpsize = iobuf_get_filelength(inp, &overflow)) && !overflow && opt.verbose) log_info(_("WARNING: '%s' is an empty file\n"), filename ); /* We can't encode the length of very large files because OpenPGP uses only 32 bit for file sizes. So if the size of a file is larger than 2^32 minus some bytes for packet headers, we switch to partial length encoding. */ if ( tmpsize < (IOBUF_FILELENGTH_LIMIT - 65536) ) filesize = tmpsize; else filesize = 0; } else filesize = opt.set_filesize ? opt.set_filesize : 0; /* stdin */ if (!opt.no_literal) { /* Note that PT has been initialized above in !no_literal mode. */ pt->timestamp = make_timestamp(); pt->mode = opt.mimemode? 'm' : opt.textmode? 't' : 'b'; pt->len = filesize; pt->new_ctb = !pt->len; pt->buf = inp; pkt.pkttype = PKT_PLAINTEXT; pkt.pkt.plaintext = pt; cfx.datalen = filesize && !do_compress ? calc_packet_length( &pkt ) : 0; } else { cfx.datalen = filesize && !do_compress ? filesize : 0; pkt.pkttype = 0; pkt.pkt.generic = NULL; } /* Register the cipher filter. */ if (mode) iobuf_push_filter ( out, cipher_filter, &cfx ); /* Register the compress filter. */ if ( do_compress ) { if (cfx.dek && cfx.dek->use_mdc) zfx.new_ctb = 1; push_compress_filter (out, &zfx, default_compress_algo()); } /* Do the work. */ if (!opt.no_literal) { if ( (rc = build_packet( out, &pkt )) ) log_error("build_packet failed: %s\n", gpg_strerror (rc) ); } else { /* User requested not to create a literal packet, so we copy the plain data. */ byte copy_buffer[4096]; int bytes_copied; while ((bytes_copied = iobuf_read(inp, copy_buffer, 4096)) != -1) if ( (rc=iobuf_write(out, copy_buffer, bytes_copied)) ) { log_error ("copying input to output failed: %s\n", gpg_strerror (rc) ); break; } wipememory (copy_buffer, 4096); /* burn buffer */ } /* Finish the stuff. */ iobuf_close (inp); if (rc) iobuf_cancel(out); else { iobuf_close (out); /* fixme: check returncode */ if (mode) write_status ( STATUS_END_ENCRYPTION ); } if (pt) pt->buf = NULL; free_packet (&pkt, NULL); xfree (cfx.dek); xfree (s2k); release_armor_context (afx); release_progress_context (pfx); return rc; } int setup_symkey (STRING2KEY **symkey_s2k,DEK **symkey_dek) { int canceled; *symkey_s2k=xmalloc_clear(sizeof(STRING2KEY)); (*symkey_s2k)->mode = opt.s2k_mode; (*symkey_s2k)->hash_algo = S2K_DIGEST_ALGO; *symkey_dek = passphrase_to_dek (opt.s2k_cipher_algo, *symkey_s2k, 1, 0, NULL, &canceled); if(!*symkey_dek || !(*symkey_dek)->keylen) { xfree(*symkey_dek); xfree(*symkey_s2k); return gpg_error (canceled?GPG_ERR_CANCELED:GPG_ERR_BAD_PASSPHRASE); } return 0; } static int write_symkey_enc (STRING2KEY *symkey_s2k, DEK *symkey_dek, DEK *dek, iobuf_t out) { int rc, seskeylen = openpgp_cipher_get_algo_keylen (dek->algo); PKT_symkey_enc *enc; byte enckey[33]; PACKET pkt; enc=xmalloc_clear(sizeof(PKT_symkey_enc)+seskeylen+1); encrypt_seskey(symkey_dek,&dek,enckey); enc->version = 4; enc->cipher_algo = opt.s2k_cipher_algo; enc->s2k = *symkey_s2k; enc->seskeylen = seskeylen + 1; /* algo id */ memcpy( enc->seskey, enckey, seskeylen + 1 ); pkt.pkttype = PKT_SYMKEY_ENC; pkt.pkt.symkey_enc = enc; if ((rc=build_packet(out,&pkt))) log_error("build symkey_enc packet failed: %s\n",gpg_strerror (rc)); xfree(enc); return rc; } /* * Encrypt the file with the given userids (or ask if none is * supplied). Either FILENAME or FILEFD must be given, but not both. * The caller may provide a checked list of public keys in * PROVIDED_PKS; if not the function builds a list of keys on its own. * * Note that FILEFD is currently only used by cmd_encrypt in the * not yet finished server.c. */ int encrypt_crypt (ctrl_t ctrl, int filefd, const char *filename, strlist_t remusr, int use_symkey, pk_list_t provided_keys, int outputfd) { iobuf_t inp = NULL; iobuf_t out = NULL; PACKET pkt; PKT_plaintext *pt = NULL; DEK *symkey_dek = NULL; STRING2KEY *symkey_s2k = NULL; int rc = 0, rc2 = 0; u32 filesize; cipher_filter_context_t cfx; armor_filter_context_t *afx = NULL; compress_filter_context_t zfx; text_filter_context_t tfx; progress_filter_context_t *pfx; PK_LIST pk_list; int do_compress; int compliant; if (filefd != -1 && filename) return gpg_error (GPG_ERR_INV_ARG); /* Both given. */ do_compress = !!opt.compress_algo; pfx = new_progress_context (); memset( &cfx, 0, sizeof cfx); memset( &zfx, 0, sizeof zfx); memset( &tfx, 0, sizeof tfx); init_packet(&pkt); if (use_symkey && (rc=setup_symkey(&symkey_s2k,&symkey_dek))) { release_progress_context (pfx); return rc; } if (provided_keys) pk_list = provided_keys; else { if ((rc = build_pk_list (ctrl, remusr, &pk_list))) { release_progress_context (pfx); return rc; } } /* Prepare iobufs. */ #ifdef HAVE_W32_SYSTEM if (filefd == -1) inp = iobuf_open (filename); else { inp = NULL; gpg_err_set_errno (ENOSYS); } #else if (filefd == GNUPG_INVALID_FD) inp = iobuf_open (filename); else inp = iobuf_fdopen_nc (FD2INT(filefd), "rb"); #endif if (inp) iobuf_ioctl (inp, IOBUF_IOCTL_NO_CACHE, 1, NULL); if (inp && is_secured_file (iobuf_get_fd (inp))) { iobuf_close (inp); inp = NULL; gpg_err_set_errno (EPERM); } if (!inp) { char xname[64]; rc = gpg_error_from_syserror (); if (filefd != -1) snprintf (xname, sizeof xname, "[fd %d]", filefd); else if (!filename) strcpy (xname, "[stdin]"); else *xname = 0; log_error (_("can't open '%s': %s\n"), *xname? xname : filename, gpg_strerror (rc) ); goto leave; } if (opt.verbose) log_info (_("reading from '%s'\n"), iobuf_get_fname_nonnull (inp)); handle_progress (pfx, inp, filename); if (opt.textmode) iobuf_push_filter (inp, text_filter, &tfx); rc = open_outfile (outputfd, filename, opt.armor? 1:0, 0, &out); if (rc) goto leave; if (opt.armor) { afx = new_armor_context (); push_armor_filter (afx, out); } /* Create a session key. */ cfx.dek = xmalloc_secure_clear (sizeof *cfx.dek); if (!opt.def_cipher_algo) { /* Try to get it from the prefs. */ cfx.dek->algo = select_algo_from_prefs (pk_list, PREFTYPE_SYM, -1, NULL); /* The only way select_algo_from_prefs can fail here is when mixing v3 and v4 keys, as v4 keys have an implicit preference entry for 3DES, and the pk_list cannot be empty. In this case, use 3DES anyway as it's the safest choice - perhaps the v3 key is being used in an OpenPGP implementation and we know that the implementation behind any v4 key can handle 3DES. */ if (cfx.dek->algo == -1) { cfx.dek->algo = CIPHER_ALGO_3DES; } /* In case 3DES has been selected, print a warning if any key does not have a preference for AES. This should help to indentify why encrypting to several recipients falls back to 3DES. */ if (opt.verbose && cfx.dek->algo == CIPHER_ALGO_3DES) warn_missing_aes_from_pklist (pk_list); } else { if (!opt.expert && (select_algo_from_prefs (pk_list, PREFTYPE_SYM, opt.def_cipher_algo, NULL) != opt.def_cipher_algo)) { log_info(_("WARNING: forcing symmetric cipher %s (%d)" " violates recipient preferences\n"), openpgp_cipher_algo_name (opt.def_cipher_algo), opt.def_cipher_algo); } cfx.dek->algo = opt.def_cipher_algo; } /* Check compliance. */ if (! gnupg_cipher_is_allowed (opt.compliance, 1, cfx.dek->algo, GCRY_CIPHER_MODE_CFB)) { log_error (_("you may not use cipher algorithm '%s'" " while in %s mode\n"), openpgp_cipher_algo_name (cfx.dek->algo), gnupg_compliance_option_string (opt.compliance)); rc = gpg_error (GPG_ERR_CIPHER_ALGO); goto leave; } if (!gnupg_rng_is_compliant (opt.compliance)) { rc = gpg_error (GPG_ERR_FORBIDDEN); log_error (_("%s is not compliant with %s mode\n"), "RNG", gnupg_compliance_option_string (opt.compliance)); write_status_error ("random-compliance", rc); goto leave; } compliant = gnupg_cipher_is_compliant (CO_DE_VS, cfx.dek->algo, GCRY_CIPHER_MODE_CFB); { pk_list_t pkr; for (pkr = pk_list; pkr; pkr = pkr->next) { PKT_public_key *pk = pkr->pk; unsigned int nbits = nbits_from_pk (pk); - if (! gnupg_pk_is_allowed (opt.compliance, PK_USE_ENCRYPTION, - pk->pubkey_algo, pk->pkey, nbits, NULL)) - { - log_error (_("key %s not suitable for encryption" - " while in %s mode\n"), - keystr_from_pk (pk), - gnupg_compliance_option_string (opt.compliance)); - rc = gpg_error (GPG_ERR_PUBKEY_ALGO); - goto leave; - } + if (!gnupg_pk_is_compliant (opt.compliance, + pk->pubkey_algo, pk->pkey, nbits, NULL)) + log_info (_("WARNING: key %s is not suitable for encryption" + " in %s mode\n"), + keystr_from_pk (pk), + gnupg_compliance_option_string (opt.compliance)); if (compliant && !gnupg_pk_is_compliant (CO_DE_VS, pk->pubkey_algo, pk->pkey, nbits, NULL)) compliant = 0; } } if (compliant) write_status_strings (STATUS_ENCRYPTION_COMPLIANCE_MODE, gnupg_status_compliance_flag (CO_DE_VS), NULL); cfx.dek->use_mdc = use_mdc (pk_list,cfx.dek->algo); /* Only do the is-file-already-compressed check if we are using a MDC. This forces compressed files to be re-compressed if we do not have a MDC to give some protection against chosen ciphertext attacks. */ if (do_compress && cfx.dek->use_mdc && is_file_compressed(filename, &rc2)) { if (opt.verbose) log_info(_("'%s' already compressed\n"), filename); do_compress = 0; } if (rc2) { rc = rc2; goto leave; } make_session_key (cfx.dek); if (DBG_CRYPTO) log_printhex ("DEK is: ", cfx.dek->key, cfx.dek->keylen ); rc = write_pubkey_enc_from_list (ctrl, pk_list, cfx.dek, out); if (rc) goto leave; /* We put the passphrase (if any) after any public keys as this seems to be the most useful on the recipient side - there is no point in prompting a user for a passphrase if they have the secret key needed to decrypt. */ if(use_symkey && (rc = write_symkey_enc(symkey_s2k,symkey_dek,cfx.dek,out))) goto leave; if (!opt.no_literal) pt = setup_plaintext_name (filename, inp); /* Get the size of the file if possible, i.e., if it is a real file. */ if (filename && *filename && !iobuf_is_pipe_filename (filename) && !opt.textmode ) { off_t tmpsize; int overflow; if ( !(tmpsize = iobuf_get_filelength(inp, &overflow)) && !overflow && opt.verbose) log_info(_("WARNING: '%s' is an empty file\n"), filename ); /* We can't encode the length of very large files because OpenPGP uses only 32 bit for file sizes. So if the size of a file is larger than 2^32 minus some bytes for packet headers, we switch to partial length encoding. */ if (tmpsize < (IOBUF_FILELENGTH_LIMIT - 65536) ) filesize = tmpsize; else filesize = 0; } else filesize = opt.set_filesize ? opt.set_filesize : 0; /* stdin */ if (!opt.no_literal) { pt->timestamp = make_timestamp(); pt->mode = opt.mimemode? 'm' : opt.textmode ? 't' : 'b'; pt->len = filesize; pt->new_ctb = !pt->len; pt->buf = inp; pkt.pkttype = PKT_PLAINTEXT; pkt.pkt.plaintext = pt; cfx.datalen = filesize && !do_compress? calc_packet_length( &pkt ) : 0; } else cfx.datalen = filesize && !do_compress ? filesize : 0; /* Register the cipher filter. */ iobuf_push_filter (out, cipher_filter, &cfx); /* Register the compress filter. */ if (do_compress) { int compr_algo = opt.compress_algo; if (compr_algo == -1) { compr_algo = select_algo_from_prefs (pk_list, PREFTYPE_ZIP, -1, NULL); if (compr_algo == -1) compr_algo = DEFAULT_COMPRESS_ALGO; /* Theoretically impossible to get here since uncompressed is implicit. */ } else if (!opt.expert && select_algo_from_prefs(pk_list, PREFTYPE_ZIP, compr_algo, NULL) != compr_algo) { log_info (_("WARNING: forcing compression algorithm %s (%d)" " violates recipient preferences\n"), compress_algo_to_string(compr_algo), compr_algo); } /* Algo 0 means no compression. */ if (compr_algo) { if (cfx.dek && cfx.dek->use_mdc) zfx.new_ctb = 1; push_compress_filter (out,&zfx,compr_algo); } } /* Do the work. */ if (!opt.no_literal) { if ((rc = build_packet( out, &pkt ))) log_error ("build_packet failed: %s\n", gpg_strerror (rc)); } else { /* User requested not to create a literal packet, so we copy the plain data. */ byte copy_buffer[4096]; int bytes_copied; while ((bytes_copied = iobuf_read (inp, copy_buffer, 4096)) != -1) { rc = iobuf_write (out, copy_buffer, bytes_copied); if (rc) { log_error ("copying input to output failed: %s\n", gpg_strerror (rc)); break; } } wipememory (copy_buffer, 4096); /* Burn the buffer. */ } /* Finish the stuff. */ leave: iobuf_close (inp); if (rc) iobuf_cancel (out); else { iobuf_close (out); /* fixme: check returncode */ write_status (STATUS_END_ENCRYPTION); } if (pt) pt->buf = NULL; free_packet (&pkt, NULL); xfree (cfx.dek); xfree (symkey_dek); xfree (symkey_s2k); if (!provided_keys) release_pk_list (pk_list); release_armor_context (afx); release_progress_context (pfx); return rc; } /* * Filter to do a complete public key encryption. */ int encrypt_filter (void *opaque, int control, iobuf_t a, byte *buf, size_t *ret_len) { size_t size = *ret_len; encrypt_filter_context_t *efx = opaque; int rc = 0; if (control == IOBUFCTRL_UNDERFLOW) /* decrypt */ { BUG(); /* not used */ } else if ( control == IOBUFCTRL_FLUSH ) /* encrypt */ { if ( !efx->header_okay ) { efx->cfx.dek = xmalloc_secure_clear ( sizeof *efx->cfx.dek ); if ( !opt.def_cipher_algo ) { /* Try to get it from the prefs. */ efx->cfx.dek->algo = select_algo_from_prefs (efx->pk_list, PREFTYPE_SYM, -1, NULL); if (efx->cfx.dek->algo == -1 ) { /* Because 3DES is implicitly in the prefs, this can only happen if we do not have any public keys in the list. */ efx->cfx.dek->algo = DEFAULT_CIPHER_ALGO; } /* In case 3DES has been selected, print a warning if any key does not have a preference for AES. This should help to indentify why encrypting to several recipients falls back to 3DES. */ if (opt.verbose && efx->cfx.dek->algo == CIPHER_ALGO_3DES) warn_missing_aes_from_pklist (efx->pk_list); } else { if (!opt.expert && select_algo_from_prefs (efx->pk_list,PREFTYPE_SYM, opt.def_cipher_algo, NULL) != opt.def_cipher_algo) log_info(_("forcing symmetric cipher %s (%d) " "violates recipient preferences\n"), openpgp_cipher_algo_name (opt.def_cipher_algo), opt.def_cipher_algo); efx->cfx.dek->algo = opt.def_cipher_algo; } efx->cfx.dek->use_mdc = use_mdc (efx->pk_list,efx->cfx.dek->algo); make_session_key ( efx->cfx.dek ); if (DBG_CRYPTO) log_printhex ("DEK is: ", efx->cfx.dek->key, efx->cfx.dek->keylen); rc = write_pubkey_enc_from_list (efx->ctrl, efx->pk_list, efx->cfx.dek, a); if (rc) return rc; if(efx->symkey_s2k && efx->symkey_dek) { rc=write_symkey_enc(efx->symkey_s2k,efx->symkey_dek, efx->cfx.dek,a); if(rc) return rc; } iobuf_push_filter (a, cipher_filter, &efx->cfx); efx->header_okay = 1; } rc = iobuf_write (a, buf, size); } else if (control == IOBUFCTRL_FREE) { xfree (efx->symkey_dek); xfree (efx->symkey_s2k); } else if ( control == IOBUFCTRL_DESC ) { mem2str (buf, "encrypt_filter", *ret_len); } return rc; } /* * Write a pubkey-enc packet for the public key PK to OUT. */ int write_pubkey_enc (ctrl_t ctrl, PKT_public_key *pk, int throw_keyid, DEK *dek, iobuf_t out) { PACKET pkt; PKT_pubkey_enc *enc; int rc; gcry_mpi_t frame; print_pubkey_algo_note ( pk->pubkey_algo ); enc = xmalloc_clear ( sizeof *enc ); enc->pubkey_algo = pk->pubkey_algo; keyid_from_pk( pk, enc->keyid ); enc->throw_keyid = throw_keyid; /* Okay, what's going on: We have the session key somewhere in * the structure DEK and want to encode this session key in an * integer value of n bits. pubkey_nbits gives us the number of * bits we have to use. We then encode the session key in some * way and we get it back in the big intger value FRAME. Then * we use FRAME, the public key PK->PKEY and the algorithm * number PK->PUBKEY_ALGO and pass it to pubkey_encrypt which * returns the encrypted value in the array ENC->DATA. This * array has a size which depends on the used algorithm (e.g. 2 * for Elgamal). We don't need frame anymore because we have * everything now in enc->data which is the passed to * build_packet(). */ frame = encode_session_key (pk->pubkey_algo, dek, pubkey_nbits (pk->pubkey_algo, pk->pkey)); rc = pk_encrypt (pk->pubkey_algo, enc->data, frame, pk, pk->pkey); gcry_mpi_release (frame); if (rc) log_error ("pubkey_encrypt failed: %s\n", gpg_strerror (rc) ); else { if ( opt.verbose ) { char *ustr = get_user_id_string_native (ctrl, enc->keyid); log_info (_("%s/%s encrypted for: \"%s\"\n"), openpgp_pk_algo_name (enc->pubkey_algo), openpgp_cipher_algo_name (dek->algo), ustr ); xfree (ustr); } /* And write it. */ init_packet (&pkt); pkt.pkttype = PKT_PUBKEY_ENC; pkt.pkt.pubkey_enc = enc; rc = build_packet (out, &pkt); if (rc) log_error ("build_packet(pubkey_enc) failed: %s\n", gpg_strerror (rc)); } free_pubkey_enc(enc); return rc; } /* * Write pubkey-enc packets from the list of PKs to OUT. */ static int write_pubkey_enc_from_list (ctrl_t ctrl, PK_LIST pk_list, DEK *dek, iobuf_t out) { if (opt.throw_keyids && (PGP6 || PGP7 || PGP8)) { log_info(_("you may not use %s while in %s mode\n"), "--throw-keyids", gnupg_compliance_option_string (opt.compliance)); compliance_failure(); } for ( ; pk_list; pk_list = pk_list->next ) { PKT_public_key *pk = pk_list->pk; int throw_keyid = (opt.throw_keyids || (pk_list->flags&1)); int rc = write_pubkey_enc (ctrl, pk, throw_keyid, dek, out); if (rc) return rc; } return 0; } void encrypt_crypt_files (ctrl_t ctrl, int nfiles, char **files, strlist_t remusr) { int rc = 0; if (opt.outfile) { log_error(_("--output doesn't work for this command\n")); return; } if (!nfiles) { char line[2048]; unsigned int lno = 0; while ( fgets(line, DIM(line), stdin) ) { lno++; if (!*line || line[strlen(line)-1] != '\n') { log_error("input line %u too long or missing LF\n", lno); return; } line[strlen(line)-1] = '\0'; print_file_status(STATUS_FILE_START, line, 2); rc = encrypt_crypt (ctrl, -1, line, remusr, 0, NULL, -1); if (rc) log_error ("encryption of '%s' failed: %s\n", print_fname_stdin(line), gpg_strerror (rc) ); write_status( STATUS_FILE_DONE ); } } else { while (nfiles--) { print_file_status(STATUS_FILE_START, *files, 2); if ( (rc = encrypt_crypt (ctrl, -1, *files, remusr, 0, NULL, -1)) ) log_error("encryption of '%s' failed: %s\n", print_fname_stdin(*files), gpg_strerror (rc) ); write_status( STATUS_FILE_DONE ); files++; } } } diff --git a/sm/encrypt.c b/sm/encrypt.c index 73519325e..0225476e7 100644 --- a/sm/encrypt.c +++ b/sm/encrypt.c @@ -1,577 +1,578 @@ /* encrypt.c - Encrypt a message * Copyright (C) 2001, 2003, 2004, 2007, 2008, * 2010 Free Software Foundation, Inc. * * This file is part of GnuPG. * * GnuPG is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 3 of the License, or * (at your option) any later version. * * GnuPG is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, see . */ #include #include #include #include #include #include #include #include #include "gpgsm.h" #include #include #include "keydb.h" #include "../common/i18n.h" #include "../common/compliance.h" struct dek_s { const char *algoid; int algo; gcry_cipher_hd_t chd; char key[32]; int keylen; char iv[32]; int ivlen; }; typedef struct dek_s *DEK; /* Callback parameters for the encryption. */ struct encrypt_cb_parm_s { estream_t fp; DEK dek; int eof_seen; int ready; int readerror; int bufsize; unsigned char *buffer; int buflen; }; /* Initialize the data encryption key (session key). */ static int init_dek (DEK dek) { int rc=0, mode, i; dek->algo = gcry_cipher_map_name (dek->algoid); mode = gcry_cipher_mode_from_oid (dek->algoid); if (!dek->algo || !mode) { log_error ("unsupported algorithm '%s'\n", dek->algoid); return gpg_error (GPG_ERR_UNSUPPORTED_ALGORITHM); } /* Extra check for algorithms we consider to be too weak for encryption, although we support them for decryption. Note that there is another check below discriminating on the key length. */ switch (dek->algo) { case GCRY_CIPHER_DES: case GCRY_CIPHER_RFC2268_40: log_error ("cipher algorithm '%s' not allowed: too weak\n", gnupg_cipher_algo_name (dek->algo)); return gpg_error (GPG_ERR_UNSUPPORTED_ALGORITHM); default: break; } dek->keylen = gcry_cipher_get_algo_keylen (dek->algo); if (!dek->keylen || dek->keylen > sizeof (dek->key)) return gpg_error (GPG_ERR_BUG); dek->ivlen = gcry_cipher_get_algo_blklen (dek->algo); if (!dek->ivlen || dek->ivlen > sizeof (dek->iv)) return gpg_error (GPG_ERR_BUG); /* Make sure we don't use weak keys. */ if (dek->keylen < 100/8) { log_error ("key length of '%s' too small\n", dek->algoid); return gpg_error (GPG_ERR_UNSUPPORTED_ALGORITHM); } rc = gcry_cipher_open (&dek->chd, dek->algo, mode, GCRY_CIPHER_SECURE); if (rc) { log_error ("failed to create cipher context: %s\n", gpg_strerror (rc)); return rc; } for (i=0; i < 8; i++) { gcry_randomize (dek->key, dek->keylen, GCRY_STRONG_RANDOM ); rc = gcry_cipher_setkey (dek->chd, dek->key, dek->keylen); if (gpg_err_code (rc) != GPG_ERR_WEAK_KEY) break; log_info(_("weak key created - retrying\n") ); } if (rc) { log_error ("failed to set the key: %s\n", gpg_strerror (rc)); gcry_cipher_close (dek->chd); dek->chd = NULL; return rc; } gcry_create_nonce (dek->iv, dek->ivlen); rc = gcry_cipher_setiv (dek->chd, dek->iv, dek->ivlen); if (rc) { log_error ("failed to set the IV: %s\n", gpg_strerror (rc)); gcry_cipher_close (dek->chd); dek->chd = NULL; return rc; } return 0; } static int encode_session_key (DEK dek, gcry_sexp_t * r_data) { gcry_sexp_t data; char *p; int rc; p = xtrymalloc (64 + 2 * dek->keylen); if (!p) return gpg_error_from_syserror (); strcpy (p, "(data\n (flags pkcs1)\n (value #"); bin2hex (dek->key, dek->keylen, p + strlen (p)); strcat (p, "#))\n"); rc = gcry_sexp_sscan (&data, NULL, p, strlen (p)); xfree (p); *r_data = data; return rc; } /* Encrypt the DEK under the key contained in CERT and return it as a canonical S-Exp in encval. */ static int encrypt_dek (const DEK dek, ksba_cert_t cert, unsigned char **encval) { gcry_sexp_t s_ciph, s_data, s_pkey; int rc; ksba_sexp_t buf; size_t len; *encval = NULL; /* get the key from the cert */ buf = ksba_cert_get_public_key (cert); if (!buf) { log_error ("no public key for recipient\n"); return gpg_error (GPG_ERR_NO_PUBKEY); } len = gcry_sexp_canon_len (buf, 0, NULL, NULL); if (!len) { log_error ("libksba did not return a proper S-Exp\n"); return gpg_error (GPG_ERR_BUG); } rc = gcry_sexp_sscan (&s_pkey, NULL, (char*)buf, len); xfree (buf); buf = NULL; if (rc) { log_error ("gcry_sexp_scan failed: %s\n", gpg_strerror (rc)); return rc; } /* Put the encoded cleartext into a simple list. */ s_data = NULL; /* (avoid compiler warning) */ rc = encode_session_key (dek, &s_data); if (rc) { log_error ("encode_session_key failed: %s\n", gpg_strerror (rc)); return rc; } /* pass it to libgcrypt */ rc = gcry_pk_encrypt (&s_ciph, s_data, s_pkey); gcry_sexp_release (s_data); gcry_sexp_release (s_pkey); /* Reformat it. */ if (!rc) { rc = make_canon_sexp (s_ciph, encval, NULL); gcry_sexp_release (s_ciph); } return rc; } /* do the actual encryption */ static int encrypt_cb (void *cb_value, char *buffer, size_t count, size_t *nread) { struct encrypt_cb_parm_s *parm = cb_value; int blklen = parm->dek->ivlen; unsigned char *p; size_t n; *nread = 0; if (!buffer) return -1; /* not supported */ if (parm->ready) return -1; if (count < blklen) BUG (); if (!parm->eof_seen) { /* fillup the buffer */ p = parm->buffer; for (n=parm->buflen; n < parm->bufsize; n++) { int c = es_getc (parm->fp); if (c == EOF) { if (es_ferror (parm->fp)) { parm->readerror = errno; return -1; } parm->eof_seen = 1; break; } p[n] = c; } parm->buflen = n; } n = parm->buflen < count? parm->buflen : count; n = n/blklen * blklen; if (n) { /* encrypt the stuff */ gcry_cipher_encrypt (parm->dek->chd, buffer, n, parm->buffer, n); *nread = n; /* Who cares about cycles, take the easy way and shift the buffer */ parm->buflen -= n; memmove (parm->buffer, parm->buffer+n, parm->buflen); } else if (parm->eof_seen) { /* no complete block but eof: add padding */ /* fixme: we should try to do this also in the above code path */ int i, npad = blklen - (parm->buflen % blklen); p = parm->buffer; for (n=parm->buflen, i=0; n < parm->bufsize && i < npad; n++, i++) p[n] = npad; gcry_cipher_encrypt (parm->dek->chd, buffer, n, parm->buffer, n); *nread = n; parm->ready = 1; } return 0; } /* Perform an encrypt operation. Encrypt the data received on DATA-FD and write it to OUT_FP. The recipients are take from the certificate given in recplist; if this is NULL it will be encrypted for a default recipient */ int gpgsm_encrypt (ctrl_t ctrl, certlist_t recplist, int data_fd, estream_t out_fp) { int rc = 0; gnupg_ksba_io_t b64writer = NULL; gpg_error_t err; ksba_writer_t writer; ksba_reader_t reader = NULL; ksba_cms_t cms = NULL; ksba_stop_reason_t stopreason; KEYDB_HANDLE kh = NULL; struct encrypt_cb_parm_s encparm; DEK dek = NULL; int recpno; estream_t data_fp = NULL; certlist_t cl; int count; int compliant; memset (&encparm, 0, sizeof encparm); audit_set_type (ctrl->audit, AUDIT_TYPE_ENCRYPT); /* Check that the certificate list is not empty and that at least one certificate is not flagged as encrypt_to; i.e. is a real recipient. */ for (cl = recplist; cl; cl = cl->next) if (!cl->is_encrypt_to) break; if (!cl) { log_error(_("no valid recipients given\n")); gpgsm_status (ctrl, STATUS_NO_RECP, "0"); audit_log_i (ctrl->audit, AUDIT_GOT_RECIPIENTS, 0); rc = gpg_error (GPG_ERR_NO_PUBKEY); goto leave; } for (count = 0, cl = recplist; cl; cl = cl->next) count++; audit_log_i (ctrl->audit, AUDIT_GOT_RECIPIENTS, count); kh = keydb_new (); if (!kh) { log_error (_("failed to allocate keyDB handle\n")); rc = gpg_error (GPG_ERR_GENERAL); goto leave; } /* Fixme: We should use the unlocked version of the es functions. */ data_fp = es_fdopen_nc (data_fd, "rb"); if (!data_fp) { rc = gpg_error_from_syserror (); log_error ("fdopen() failed: %s\n", strerror (errno)); goto leave; } err = ksba_reader_new (&reader); if (err) rc = err; if (!rc) rc = ksba_reader_set_cb (reader, encrypt_cb, &encparm); if (rc) goto leave; encparm.fp = data_fp; ctrl->pem_name = "ENCRYPTED MESSAGE"; rc = gnupg_ksba_create_writer (&b64writer, ((ctrl->create_pem? GNUPG_KSBA_IO_PEM : 0) | (ctrl->create_base64? GNUPG_KSBA_IO_BASE64 : 0)), ctrl->pem_name, out_fp, &writer); if (rc) { log_error ("can't create writer: %s\n", gpg_strerror (rc)); goto leave; } err = ksba_cms_new (&cms); if (err) { rc = err; goto leave; } err = ksba_cms_set_reader_writer (cms, reader, writer); if (err) { log_debug ("ksba_cms_set_reader_writer failed: %s\n", gpg_strerror (err)); rc = err; goto leave; } audit_log (ctrl->audit, AUDIT_GOT_DATA); /* We are going to create enveloped data with uninterpreted data as inner content */ err = ksba_cms_set_content_type (cms, 0, KSBA_CT_ENVELOPED_DATA); if (!err) err = ksba_cms_set_content_type (cms, 1, KSBA_CT_DATA); if (err) { log_debug ("ksba_cms_set_content_type failed: %s\n", gpg_strerror (err)); rc = err; goto leave; } /* Check compliance. */ if (!gnupg_cipher_is_allowed (opt.compliance, 1, gcry_cipher_map_name (opt.def_cipher_algoid), gcry_cipher_mode_from_oid (opt.def_cipher_algoid))) { log_error (_("you may not use cipher algorithm '%s'" " while in %s mode\n"), opt.def_cipher_algoid, gnupg_compliance_option_string (opt.compliance)); rc = gpg_error (GPG_ERR_CIPHER_ALGO); goto leave; } if (!gnupg_rng_is_compliant (opt.compliance)) { rc = gpg_error (GPG_ERR_FORBIDDEN); log_error (_("%s is not compliant with %s mode\n"), "RNG", gnupg_compliance_option_string (opt.compliance)); gpgsm_status_with_error (ctrl, STATUS_ERROR, "random-compliance", rc); goto leave; } /* Create a session key */ dek = xtrycalloc_secure (1, sizeof *dek); if (!dek) rc = out_of_core (); else { dek->algoid = opt.def_cipher_algoid; rc = init_dek (dek); } if (rc) { log_error ("failed to create the session key: %s\n", gpg_strerror (rc)); goto leave; } err = ksba_cms_set_content_enc_algo (cms, dek->algoid, dek->iv, dek->ivlen); if (err) { log_error ("ksba_cms_set_content_enc_algo failed: %s\n", gpg_strerror (err)); rc = err; goto leave; } encparm.dek = dek; /* Use a ~8k (AES) or ~4k (3DES) buffer */ encparm.bufsize = 500 * dek->ivlen; encparm.buffer = xtrymalloc (encparm.bufsize); if (!encparm.buffer) { rc = out_of_core (); goto leave; } audit_log_s (ctrl->audit, AUDIT_SESSION_KEY, dek->algoid); compliant = gnupg_cipher_is_compliant (CO_DE_VS, dek->algo, GCRY_CIPHER_MODE_CBC); /* Gather certificates of recipients, encrypt the session key for each and store them in the CMS object */ for (recpno = 0, cl = recplist; cl; recpno++, cl = cl->next) { unsigned char *encval; unsigned int nbits; int pk_algo; /* Check compliance. */ pk_algo = gpgsm_get_key_algo_info (cl->cert, &nbits); - if (! gnupg_pk_is_allowed (opt.compliance, PK_USE_ENCRYPTION, pk_algo, - NULL, nbits, NULL)) + if (!gnupg_pk_is_compliant (opt.compliance, pk_algo, NULL, nbits, NULL)) { - log_error ("certificate ID 0x%08lX not suitable for " - "encryption while in %s mode\n", - gpgsm_get_short_fingerprint (cl->cert, NULL), - gnupg_compliance_option_string (opt.compliance)); - rc = gpg_error (GPG_ERR_PUBKEY_ALGO); - goto leave; + char kidstr[10+1]; + + snprintf (kidstr, sizeof kidstr, "0x%08lX", + gpgsm_get_short_fingerprint (cl->cert, NULL)); + log_info (_("WARNING: key %s is not suitable for encryption" + " in %s mode\n"), + kidstr, + gnupg_compliance_option_string (opt.compliance)); } /* Fixme: When adding ECC we need to provide the curvename and * the key to gnupg_pk_is_compliant. */ if (compliant && !gnupg_pk_is_compliant (CO_DE_VS, pk_algo, NULL, nbits, NULL)) compliant = 0; rc = encrypt_dek (dek, cl->cert, &encval); if (rc) { audit_log_cert (ctrl->audit, AUDIT_ENCRYPTED_TO, cl->cert, rc); log_error ("encryption failed for recipient no. %d: %s\n", recpno, gpg_strerror (rc)); goto leave; } err = ksba_cms_add_recipient (cms, cl->cert); if (err) { audit_log_cert (ctrl->audit, AUDIT_ENCRYPTED_TO, cl->cert, err); log_error ("ksba_cms_add_recipient failed: %s\n", gpg_strerror (err)); rc = err; xfree (encval); goto leave; } err = ksba_cms_set_enc_val (cms, recpno, encval); xfree (encval); audit_log_cert (ctrl->audit, AUDIT_ENCRYPTED_TO, cl->cert, err); if (err) { log_error ("ksba_cms_set_enc_val failed: %s\n", gpg_strerror (err)); rc = err; goto leave; } } if (compliant) gpgsm_status (ctrl, STATUS_ENCRYPTION_COMPLIANCE_MODE, gnupg_status_compliance_flag (CO_DE_VS)); /* Main control loop for encryption. */ recpno = 0; do { err = ksba_cms_build (cms, &stopreason); if (err) { log_debug ("ksba_cms_build failed: %s\n", gpg_strerror (err)); rc = err; goto leave; } } while (stopreason != KSBA_SR_READY); if (encparm.readerror) { log_error ("error reading input: %s\n", strerror (encparm.readerror)); rc = gpg_error (gpg_err_code_from_errno (encparm.readerror)); goto leave; } rc = gnupg_ksba_finish_writer (b64writer); if (rc) { log_error ("write failed: %s\n", gpg_strerror (rc)); goto leave; } audit_log (ctrl->audit, AUDIT_ENCRYPTION_DONE); log_info ("encrypted data created\n"); leave: ksba_cms_release (cms); gnupg_ksba_destroy_writer (b64writer); ksba_reader_release (reader); keydb_release (kh); xfree (dek); es_fclose (data_fp); xfree (encparm.buffer); return rc; }