/* sign.c - sign data * Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, * 2006 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 "gpg.h" #include "options.h" #include "packet.h" #include "errors.h" #include "iobuf.h" #include "keydb.h" #include "util.h" #include "main.h" #include "filter.h" #include "ttyio.h" #include "trustdb.h" #include "status.h" #include "i18n.h" #include "pkglue.h" #include "sysutils.h" #include "call-agent.h" #ifdef HAVE_DOSISH_SYSTEM #define LF "\r\n" #else #define LF "\n" #endif static int recipient_digest_algo=0; /**************** * Create notations and other stuff. It is assumed that the stings in * STRLIST are already checked to contain only printable data and have * a valid NAME=VALUE format. */ static void mk_notation_policy_etc( PKT_signature *sig, PKT_public_key *pk, PKT_secret_key *sk ) { const char *string; char *s=NULL; strlist_t pu=NULL; struct notation *nd=NULL; struct expando_args args; memset(&args,0,sizeof(args)); args.pk=pk; args.sk=sk; /* It is actually impossible to get here when making a v3 key signature since keyedit.c:sign_uids will automatically bump a signature with a notation or policy url up to v4, but it is good to do these checks anyway. */ /* notation data */ if(IS_SIG(sig) && opt.sig_notations) { if(sig->version<4) log_error(_("can't put notation data into v3 (PGP 2.x style) " "signatures\n")); else nd=opt.sig_notations; } else if( IS_CERT(sig) && opt.cert_notations ) { if(sig->version<4) log_error(_("can't put notation data into v3 (PGP 2.x style) " "key signatures\n")); else nd=opt.cert_notations; } if(nd) { struct notation *i; for(i=nd;i;i=i->next) { i->altvalue=pct_expando(i->value,&args); if(!i->altvalue) log_error(_("WARNING: unable to %%-expand notation " "(too large). Using unexpanded.\n")); } keygen_add_notations(sig,nd); for(i=nd;i;i=i->next) { xfree(i->altvalue); i->altvalue=NULL; } } /* set policy URL */ if( IS_SIG(sig) && opt.sig_policy_url ) { if(sig->version<4) log_error(_("can't put a policy URL into v3 (PGP 2.x style) " "signatures\n")); else pu=opt.sig_policy_url; } else if( IS_CERT(sig) && opt.cert_policy_url ) { if(sig->version<4) log_error(_("can't put a policy URL into v3 key (PGP 2.x style) " "signatures\n")); else pu=opt.cert_policy_url; } for(;pu;pu=pu->next) { string = pu->d; s=pct_expando(string,&args); if(!s) { log_error(_("WARNING: unable to %%-expand policy URL " "(too large). Using unexpanded.\n")); s=xstrdup(string); } build_sig_subpkt(sig,SIGSUBPKT_POLICY| ((pu->flags & 1)?SIGSUBPKT_FLAG_CRITICAL:0), s,strlen(s)); xfree(s); } /* preferred keyserver URL */ if( IS_SIG(sig) && opt.sig_keyserver_url ) { if(sig->version<4) log_info("can't put a preferred keyserver URL into v3 signatures\n"); else pu=opt.sig_keyserver_url; } for(;pu;pu=pu->next) { string = pu->d; s=pct_expando(string,&args); if(!s) { log_error(_("WARNING: unable to %%-expand preferred keyserver URL" " (too large). Using unexpanded.\n")); s=xstrdup(string); } build_sig_subpkt(sig,SIGSUBPKT_PREF_KS| ((pu->flags & 1)?SIGSUBPKT_FLAG_CRITICAL:0), s,strlen(s)); xfree(s); } } /* * Helper to hash a user ID packet. */ static void hash_uid (gcry_md_hd_t md, int sigversion, const PKT_user_id *uid) { if ( sigversion >= 4 ) { byte buf[5]; if(uid->attrib_data) { buf[0] = 0xd1; /* indicates an attribute packet */ buf[1] = uid->attrib_len >> 24; /* always use 4 length bytes */ buf[2] = uid->attrib_len >> 16; buf[3] = uid->attrib_len >> 8; buf[4] = uid->attrib_len; } else { buf[0] = 0xb4; /* indicates a userid packet */ buf[1] = uid->len >> 24; /* always use 4 length bytes */ buf[2] = uid->len >> 16; buf[3] = uid->len >> 8; buf[4] = uid->len; } gcry_md_write( md, buf, 5 ); } if(uid->attrib_data) gcry_md_write (md, uid->attrib_data, uid->attrib_len ); else gcry_md_write (md, uid->name, uid->len ); } /* * Helper to hash some parts from the signature */ static void hash_sigversion_to_magic (gcry_md_hd_t md, const PKT_signature *sig) { if (sig->version >= 4) gcry_md_putc (md, sig->version); gcry_md_putc (md, sig->sig_class); if (sig->version < 4) { u32 a = sig->timestamp; gcry_md_putc (md, (a >> 24) & 0xff ); gcry_md_putc (md, (a >> 16) & 0xff ); gcry_md_putc (md, (a >> 8) & 0xff ); gcry_md_putc (md, a & 0xff ); } else { byte buf[6]; size_t n; gcry_md_putc (md, sig->pubkey_algo); gcry_md_putc (md, sig->digest_algo); if (sig->hashed) { n = sig->hashed->len; gcry_md_putc (md, (n >> 8) ); gcry_md_putc (md, n ); gcry_md_write (md, sig->hashed->data, n ); n += 6; } else { gcry_md_putc (md, 0); /* always hash the length of the subpacket*/ gcry_md_putc (md, 0); n = 6; } /* add some magic */ buf[0] = sig->version; buf[1] = 0xff; buf[2] = n >> 24; /* hmmm, n is only 16 bit, so this is always 0 */ buf[3] = n >> 16; buf[4] = n >> 8; buf[5] = n; gcry_md_write (md, buf, 6); } } static int do_sign( PKT_secret_key *sk, PKT_signature *sig, gcry_md_hd_t md, int digest_algo ) { gcry_mpi_t frame; byte *dp; int rc; if( sk->timestamp > sig->timestamp ) { ulong d = sk->timestamp - sig->timestamp; log_info( d==1 ? _("key has been created %lu second " "in future (time warp or clock problem)\n") : _("key has been created %lu seconds " "in future (time warp or clock problem)\n"), d ); if( !opt.ignore_time_conflict ) return G10ERR_TIME_CONFLICT; } print_pubkey_algo_note(sk->pubkey_algo); if( !digest_algo ) digest_algo = gcry_md_get_algo (md); print_digest_algo_note( digest_algo ); dp = gcry_md_read ( md, digest_algo ); sig->digest_algo = digest_algo; sig->digest_start[0] = dp[0]; sig->digest_start[1] = dp[1]; if (sk->is_protected && sk->protect.s2k.mode == 1002) { #ifdef ENABLE_CARD_SUPPORT unsigned char *rbuf; size_t rbuflen; char *snbuf; snbuf = serialno_and_fpr_from_sk (sk->protect.iv, sk->protect.ivlen, sk); rc = agent_scd_pksign (snbuf, digest_algo, gcry_md_read (md, digest_algo), gcry_md_get_algo_dlen (digest_algo), &rbuf, &rbuflen); xfree (snbuf); if (!rc) { if (gcry_mpi_scan (&sig->data[0], GCRYMPI_FMT_USG, rbuf, rbuflen, NULL)) BUG (); xfree (rbuf); } #else return gpg_error (GPG_ERR_NOT_SUPPORTED); #endif /* ENABLE_CARD_SUPPORT */ } else { frame = encode_md_value( NULL, sk, md, digest_algo ); if (!frame) return G10ERR_GENERAL; rc = pk_sign( sk->pubkey_algo, sig->data, frame, sk->skey ); gcry_mpi_release (frame); } if (!rc && !opt.no_sig_create_check) { /* Check that the signature verification worked and nothing is * fooling us e.g. by a bug in the signature create * code or by deliberately introduced faults. */ PKT_public_key *pk = xmalloc_clear (sizeof *pk); if( get_pubkey( pk, sig->keyid ) ) rc = G10ERR_NO_PUBKEY; else { frame = encode_md_value (pk, NULL, md, sig->digest_algo ); if (!frame) rc = G10ERR_GENERAL; else rc = pk_verify (pk->pubkey_algo, frame, sig->data, pk->pkey ); gcry_mpi_release (frame); } if (rc) log_error (_("checking created signature failed: %s\n"), g10_errstr (rc)); free_public_key (pk); } if( rc ) log_error(_("signing failed: %s\n"), g10_errstr(rc) ); else { if( opt.verbose ) { char *ustr = get_user_id_string_native (sig->keyid); log_info(_("%s/%s signature from: \"%s\"\n"), gcry_pk_algo_name (sk->pubkey_algo), gcry_md_algo_name (sig->digest_algo), ustr ); xfree(ustr); } } return rc; } int complete_sig( PKT_signature *sig, PKT_secret_key *sk, gcry_md_hd_t md ) { int rc=0; if( !(rc=check_secret_key( sk, 0 )) ) rc = do_sign( sk, sig, md, 0 ); return rc; } static int match_dsa_hash (unsigned int qbytes) { if (qbytes <= 20) return DIGEST_ALGO_SHA1; #ifdef USE_SHA256 if (qbytes <= 28) return DIGEST_ALGO_SHA224; if (qbytes <= 32) return DIGEST_ALGO_SHA256; #endif #ifdef USE_SHA512 if (qbytes <= 48) return DIGEST_ALGO_SHA384; if (qbytes <= 64) return DIGEST_ALGO_SHA512; #endif return DEFAULT_DIGEST_ALGO; /* DEFAULT_DIGEST_ALGO will certainly fail, but it's the best wrong answer we have if the larger SHAs aren't there. */ } /* First try --digest-algo. If that isn't set, see if the recipient has a preferred algorithm (which is also filtered through --preferred-digest-prefs). If we're making a signature without a particular recipient (i.e. signing, rather than signing+encrypting) then take the first algorithm in --preferred-digest-prefs that is usable for the pubkey algorithm. If --preferred-digest-prefs isn't set, then take the OpenPGP default (i.e. SHA-1). Possible improvement: Use the highest-ranked usable algorithm from the signing key prefs either before or after using the personal list? */ static int hash_for(PKT_secret_key *sk) { if( opt.def_digest_algo ) return opt.def_digest_algo; else if( recipient_digest_algo ) return recipient_digest_algo; else if(sk->pubkey_algo==PUBKEY_ALGO_DSA) { unsigned int qbytes = gcry_mpi_get_nbits (sk->skey[1]) / 8; /* It's a DSA key, so find a hash that is the same size as q or larger. If q is 160, assume it is an old DSA key and use a 160-bit hash unless --enable-dsa2 is set, in which case act like a new DSA key that just happens to have a 160-bit q (i.e. allow truncation). If q is not 160, by definition it must be a new DSA key. */ if (opt.personal_digest_prefs) { prefitem_t *prefs; if (qbytes != 20 || opt.flags.dsa2) { for (prefs=opt.personal_digest_prefs; prefs->type; prefs++) if (gcry_md_get_algo_dlen (prefs->value) >= qbytes) return prefs->value; } else { for (prefs=opt.personal_digest_prefs; prefs->type; prefs++) if (gcry_md_get_algo_dlen (prefs->value) == qbytes) return prefs->value; } } return match_dsa_hash(qbytes); } else if (sk->is_protected && sk->protect.s2k.mode==1002) { /* The sk lives on a smartcard, and current smartcards only handle SHA-1 and RIPEMD/160. This is correct now, but may need revision as the cards add algorithms. */ if(opt.personal_digest_prefs) { prefitem_t *prefs; for (prefs=opt.personal_digest_prefs;prefs->type;prefs++) if (prefs->value==DIGEST_ALGO_SHA1 || prefs->value==DIGEST_ALGO_RMD160) return prefs->value; } return DIGEST_ALGO_SHA1; } else if (PGP2 && sk->pubkey_algo == PUBKEY_ALGO_RSA && sk->version < 4 ) { /* Old-style PGP only understands MD5 */ return DIGEST_ALGO_MD5; } else if ( opt.personal_digest_prefs ) { /* It's not DSA, so we can use whatever the first hash algorithm is in the pref list */ return opt.personal_digest_prefs[0].value; } else return DEFAULT_DIGEST_ALGO; } static int only_old_style( SK_LIST sk_list ) { SK_LIST sk_rover = NULL; int old_style = 0; /* if there are only old style capable key we use the old sytle */ for( sk_rover = sk_list; sk_rover; sk_rover = sk_rover->next ) { PKT_secret_key *sk = sk_rover->sk; if( sk->pubkey_algo == PUBKEY_ALGO_RSA && sk->version < 4 ) old_style = 1; else return 0; } return old_style; } static void print_status_sig_created ( PKT_secret_key *sk, PKT_signature *sig, int what ) { byte array[MAX_FINGERPRINT_LEN], *p; char buf[100+MAX_FINGERPRINT_LEN*2]; size_t i, n; sprintf(buf, "%c %d %d %02x %lu ", what, sig->pubkey_algo, sig->digest_algo, sig->sig_class, (ulong)sig->timestamp ); fingerprint_from_sk( sk, array, &n ); p = buf + strlen(buf); for(i=0; i < n ; i++ ) sprintf(p+2*i, "%02X", array[i] ); write_status_text( STATUS_SIG_CREATED, buf ); } /* * Loop over the secret certificates in SK_LIST and build the one pass * signature packets. OpenPGP says that the data should be bracket by * the onepass-sig and signature-packet; so we build these onepass * packet here in reverse order */ static int write_onepass_sig_packets (SK_LIST sk_list, IOBUF out, int sigclass ) { int skcount; SK_LIST sk_rover; for (skcount=0, sk_rover=sk_list; sk_rover; sk_rover = sk_rover->next) skcount++; for (; skcount; skcount--) { PKT_secret_key *sk; PKT_onepass_sig *ops; PACKET pkt; int i, rc; for (i=0, sk_rover = sk_list; sk_rover; sk_rover = sk_rover->next ) { if (++i == skcount) break; } sk = sk_rover->sk; ops = xmalloc_clear (sizeof *ops); ops->sig_class = sigclass; ops->digest_algo = hash_for (sk); ops->pubkey_algo = sk->pubkey_algo; keyid_from_sk (sk, ops->keyid); ops->last = (skcount == 1); init_packet(&pkt); pkt.pkttype = PKT_ONEPASS_SIG; pkt.pkt.onepass_sig = ops; rc = build_packet (out, &pkt); free_packet (&pkt); if (rc) { log_error ("build onepass_sig packet failed: %s\n", g10_errstr(rc)); return rc; } } return 0; } /* * Helper to write the plaintext (literal data) packet */ static int write_plaintext_packet (IOBUF out, IOBUF inp, const char *fname, int ptmode) { PKT_plaintext *pt = NULL; u32 filesize; int rc = 0; if (!opt.no_literal) pt=setup_plaintext_name(fname,inp); /* try to calculate the length of the data */ if ( !iobuf_is_pipe_filename (fname) && *fname ) { off_t tmpsize; int overflow; if( !(tmpsize = iobuf_get_filelength(inp, &overflow)) && !overflow ) log_info (_("WARNING: `%s' is an empty file\n"), fname); /* 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; /* Because the text_filter modifies the length of the * data, it is not possible to know the used length * without a double read of the file - to avoid that * we simple use partial length packets. */ if ( ptmode == 't' ) filesize = 0; } else filesize = opt.set_filesize? opt.set_filesize : 0; /* stdin */ if (!opt.no_literal) { PACKET pkt; pt->timestamp = make_timestamp (); pt->mode = ptmode; pt->len = filesize; pt->new_ctb = !pt->len && !RFC1991; pt->buf = inp; init_packet(&pkt); pkt.pkttype = PKT_PLAINTEXT; pkt.pkt.plaintext = pt; /*cfx.datalen = filesize? calc_packet_length( &pkt ) : 0;*/ if( (rc = build_packet (out, &pkt)) ) log_error ("build_packet(PLAINTEXT) failed: %s\n", g10_errstr(rc) ); pt->buf = NULL; } else { 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 */ } /* fixme: it seems that we never freed pt/pkt */ return rc; } /* * Write the signatures from the SK_LIST to OUT. HASH must be a non-finalized * hash which will not be changes here. */ static int write_signature_packets (SK_LIST sk_list, IOBUF out, gcry_md_hd_t hash, int sigclass, u32 timestamp, u32 duration, int status_letter) { SK_LIST sk_rover; /* loop over the secret certificates */ for (sk_rover = sk_list; sk_rover; sk_rover = sk_rover->next) { PKT_secret_key *sk; PKT_signature *sig; gcry_md_hd_t md; int rc; sk = sk_rover->sk; /* build the signature packet */ sig = xmalloc_clear (sizeof *sig); if(opt.force_v3_sigs || RFC1991) sig->version=3; else if(duration || opt.sig_policy_url || opt.sig_notations || opt.sig_keyserver_url) sig->version=4; else sig->version=sk->version; keyid_from_sk (sk, sig->keyid); sig->digest_algo = hash_for(sk); sig->pubkey_algo = sk->pubkey_algo; if(timestamp) sig->timestamp = timestamp; else sig->timestamp = make_timestamp(); if(duration) sig->expiredate = sig->timestamp+duration; sig->sig_class = sigclass; if (gcry_md_copy (&md, hash)) BUG (); if (sig->version >= 4) build_sig_subpkt_from_sig (sig); mk_notation_policy_etc (sig, NULL, sk); hash_sigversion_to_magic (md, sig); gcry_md_final (md); rc = do_sign( sk, sig, md, hash_for (sk) ); gcry_md_close (md); if( !rc ) { /* and write it */ PACKET pkt; init_packet(&pkt); pkt.pkttype = PKT_SIGNATURE; pkt.pkt.signature = sig; rc = build_packet (out, &pkt); if (!rc && is_status_enabled()) { print_status_sig_created ( sk, sig, status_letter); } free_packet (&pkt); if (rc) log_error ("build signature packet failed: %s\n", g10_errstr(rc) ); } if( rc ) return rc;; } return 0; } /**************** * Sign the files whose names are in FILENAME. * If DETACHED has the value true, * make a detached signature. If FILENAMES->d is NULL read from stdin * and ignore the detached mode. Sign the file with all secret keys * which can be taken from LOCUSR, if this is NULL, use the default one * If ENCRYPTFLAG is true, use REMUSER (or ask if it is NULL) to encrypt the * signed data for these users. * If OUTFILE is not NULL; this file is used for output and the function * does not ask for overwrite permission; output is then always * uncompressed, non-armored and in binary mode. */ int sign_file( strlist_t filenames, int detached, strlist_t locusr, int encryptflag, strlist_t remusr, const char *outfile ) { const char *fname; armor_filter_context_t *afx; compress_filter_context_t zfx; md_filter_context_t mfx; text_filter_context_t tfx; progress_filter_context_t *pfx; encrypt_filter_context_t efx; IOBUF inp = NULL, out = NULL; PACKET pkt; int rc = 0; PK_LIST pk_list = NULL; SK_LIST sk_list = NULL; SK_LIST sk_rover = NULL; int multifile = 0; u32 duration=0; pfx = new_progress_context (); afx = new_armor_context (); memset( &zfx, 0, sizeof zfx); memset( &mfx, 0, sizeof mfx); memset( &efx, 0, sizeof efx); init_packet( &pkt ); if( filenames ) { fname = filenames->d; multifile = !!filenames->next; } else fname = NULL; if( fname && filenames->next && (!detached || encryptflag) ) log_bug("multiple files can only be detached signed"); if(encryptflag==2 && (rc=setup_symkey(&efx.symkey_s2k,&efx.symkey_dek))) goto leave; if(!opt.force_v3_sigs && !RFC1991) { if(opt.ask_sig_expire && !opt.batch) duration=ask_expire_interval(1,opt.def_sig_expire); else duration=parse_expire_string(opt.def_sig_expire); } if( (rc=build_sk_list( locusr, &sk_list, 1, PUBKEY_USAGE_SIG )) ) goto leave; if(PGP2 && !only_old_style(sk_list)) { log_info(_("you can only detach-sign with PGP 2.x style keys " "while in --pgp2 mode\n")); compliance_failure(); } if(encryptflag && (rc=build_pk_list( remusr, &pk_list, PUBKEY_USAGE_ENC ))) goto leave; /* prepare iobufs */ if( multifile ) /* have list of filenames */ inp = NULL; /* we do it later */ else { inp = iobuf_open(fname); if (inp && is_secured_file (iobuf_get_fd (inp))) { iobuf_close (inp); inp = NULL; errno = EPERM; } if( !inp ) { rc = gpg_error_from_syserror (); log_error (_("can't open `%s': %s\n"), fname? fname: "[stdin]", strerror(errno) ); goto leave; } handle_progress (pfx, inp, fname); } if( outfile ) { if (is_secured_filename ( outfile )) { out = NULL; errno = EPERM; } else out = iobuf_create( outfile ); if( !out ) { rc = gpg_error_from_syserror (); log_error(_("can't create `%s': %s\n"), outfile, strerror(errno) ); goto leave; } else if( opt.verbose ) log_info(_("writing to `%s'\n"), outfile ); } else if( (rc = open_outfile( fname, opt.armor? 1: detached? 2:0, &out ))) goto leave; /* prepare to calculate the MD over the input */ if( opt.textmode && !outfile && !multifile ) { memset( &tfx, 0, sizeof tfx); iobuf_push_filter( inp, text_filter, &tfx ); } if ( gcry_md_open (&mfx.md, 0, 0) ) BUG (); if (DBG_HASHING) gcry_md_start_debug (mfx.md, "sign"); /* If we're encrypting and signing, it is reasonable to pick the hash algorithm to use out of the recepient key prefs. This is best effort only, as in a DSA2 and smartcard world there are cases where we cannot please everyone with a single hash (DSA2 wants >160 and smartcards want =160). In the future this could be more complex with different hashes for each sk, but the current design requires a single hash for all SKs. */ if(pk_list) { if(opt.def_digest_algo) { if(!opt.expert && select_algo_from_prefs(pk_list,PREFTYPE_HASH, opt.def_digest_algo, NULL)!=opt.def_digest_algo) log_info(_("WARNING: forcing digest algorithm %s (%d)" " violates recipient preferences\n"), gcry_md_algo_name (opt.def_digest_algo), opt.def_digest_algo ); } else { int algo, smartcard=0; union pref_hint hint; hint.digest_length = 0; /* Of course, if the recipient asks for something unreasonable (like the wrong hash for a DSA key) then don't do it. Check all sk's - if any are DSA or live on a smartcard, then the hash has restrictions and we may not be able to give the recipient what they want. For DSA, pass a hint for the largest q we have. Note that this means that a q>160 key will override a q=160 key and force the use of truncation for the q=160 key. The alternative would be to ignore the recipient prefs completely and get a different hash for each DSA key in hash_for(). The override behavior here is more or less reasonable as it is under the control of the user which keys they sign with for a given message and the fact that the message with multiple signatures won't be usable on an implementation that doesn't understand DSA2 anyway. */ for (sk_rover = sk_list; sk_rover; sk_rover = sk_rover->next ) { if (sk_rover->sk->pubkey_algo == PUBKEY_ALGO_DSA) { int temp_hashlen = gcry_mpi_get_nbits (sk_rover->sk->skey[1])+7/8; /* Pick a hash that is large enough for our largest q */ if (hint.digest_lengthsk->is_protected && sk_rover->sk->protect.s2k.mode == 1002) smartcard = 1; } /* Current smartcards only do 160-bit hashes. If we have to have a >160-bit hash, then we can't use the recipient prefs as we'd need both =160 and >160 at the same time and recipient prefs currently require a single hash for all signatures. All this may well have to change as the cards add algorithms. */ if (!smartcard || (smartcard && hint.digest_length==20)) if ( (algo= select_algo_from_prefs(pk_list,PREFTYPE_HASH,-1,&hint)) > 0) recipient_digest_algo=algo; } } for( sk_rover = sk_list; sk_rover; sk_rover = sk_rover->next ) { PKT_secret_key *sk = sk_rover->sk; gcry_md_enable (mfx.md, hash_for(sk)); } if( !multifile ) iobuf_push_filter( inp, md_filter, &mfx ); if( detached && !encryptflag && !RFC1991 ) afx->what = 2; if( opt.armor && !outfile ) push_armor_filter (afx, out); if( encryptflag ) { efx.pk_list = pk_list; /* fixme: set efx.cfx.datalen if known */ iobuf_push_filter( out, encrypt_filter, &efx ); } if( opt.compress_algo && !outfile && ( !detached || opt.compress_sigs) ) { int compr_algo=opt.compress_algo; /* If not forced by user */ if(compr_algo==-1) { /* If we're not encrypting, then select_algo_from_prefs will fail and we'll end up with the default. If we are encrypting, select_algo_from_prefs cannot fail since there is an assumed preference for uncompressed data. Still, if it did fail, we'll also end up with the default. */ if((compr_algo= select_algo_from_prefs(pk_list,PREFTYPE_ZIP,-1,NULL))==-1) compr_algo=default_compress_algo(); } else if(!opt.expert && pk_list && 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 ) push_compress_filter(out,&zfx,compr_algo); } /* Write the one-pass signature packets if needed */ if (!detached && !RFC1991) { rc = write_onepass_sig_packets (sk_list, out, opt.textmode && !outfile ? 0x01:0x00); if (rc) goto leave; } write_status_begin_signing (mfx.md); /* Setup the inner packet. */ if( detached ) { if( multifile ) { strlist_t sl; if( opt.verbose ) log_info(_("signing:") ); /* must walk reverse trough this list */ for( sl = strlist_last(filenames); sl; sl = strlist_prev( filenames, sl ) ) { inp = iobuf_open(sl->d); if (inp && is_secured_file (iobuf_get_fd (inp))) { iobuf_close (inp); inp = NULL; errno = EPERM; } if( !inp ) { rc = gpg_error_from_syserror (); log_error(_("can't open `%s': %s\n"), sl->d,strerror(errno)); goto leave; } handle_progress (pfx, inp, sl->d); if( opt.verbose ) fprintf(stderr, " `%s'", sl->d ); if(opt.textmode) { memset( &tfx, 0, sizeof tfx); iobuf_push_filter( inp, text_filter, &tfx ); } iobuf_push_filter( inp, md_filter, &mfx ); while( iobuf_get(inp) != -1 ) ; iobuf_close(inp); inp = NULL; } if( opt.verbose ) putc( '\n', stderr ); } else { /* read, so that the filter can calculate the digest */ while( iobuf_get(inp) != -1 ) ; } } else { rc = write_plaintext_packet (out, inp, fname, opt.textmode && !outfile ? 't':'b'); } /* catch errors from above */ if (rc) goto leave; /* write the signatures */ rc = write_signature_packets (sk_list, out, mfx.md, opt.textmode && !outfile? 0x01 : 0x00, 0, duration, detached ? 'D':'S'); if( rc ) goto leave; leave: if( rc ) iobuf_cancel(out); else { iobuf_close(out); if (encryptflag) write_status( STATUS_END_ENCRYPTION ); } iobuf_close(inp); gcry_md_close ( mfx.md ); release_sk_list( sk_list ); release_pk_list( pk_list ); recipient_digest_algo=0; release_progress_context (pfx); release_armor_context (afx); return rc; } /**************** * make a clear signature. note that opt.armor is not needed */ int clearsign_file( const char *fname, strlist_t locusr, const char *outfile ) { armor_filter_context_t *afx; progress_filter_context_t *pfx; gcry_md_hd_t textmd = NULL; IOBUF inp = NULL, out = NULL; PACKET pkt; int rc = 0; SK_LIST sk_list = NULL; SK_LIST sk_rover = NULL; int old_style = RFC1991; int only_md5 = 0; u32 duration=0; pfx = new_progress_context (); afx = new_armor_context (); init_packet( &pkt ); if(!opt.force_v3_sigs && !RFC1991) { if(opt.ask_sig_expire && !opt.batch) duration=ask_expire_interval(1,opt.def_sig_expire); else duration=parse_expire_string(opt.def_sig_expire); } if( (rc=build_sk_list( locusr, &sk_list, 1, PUBKEY_USAGE_SIG )) ) goto leave; if( !old_style && !duration ) old_style = only_old_style( sk_list ); if(PGP2 && !only_old_style(sk_list)) { log_info(_("you can only clearsign with PGP 2.x style keys " "while in --pgp2 mode\n")); compliance_failure(); } /* prepare iobufs */ inp = iobuf_open(fname); if (inp && is_secured_file (iobuf_get_fd (inp))) { iobuf_close (inp); inp = NULL; errno = EPERM; } if( !inp ) { rc = gpg_error_from_syserror (); log_error (_("can't open `%s': %s\n"), fname? fname: "[stdin]", strerror(errno) ); goto leave; } handle_progress (pfx, inp, fname); if( outfile ) { if (is_secured_filename (outfile) ) { outfile = NULL; errno = EPERM; } else out = iobuf_create( outfile ); if( !out ) { rc = gpg_error_from_syserror (); log_error(_("can't create `%s': %s\n"), outfile, strerror(errno) ); goto leave; } else if( opt.verbose ) log_info(_("writing to `%s'\n"), outfile ); } else if( (rc = open_outfile( fname, 1, &out )) ) goto leave; iobuf_writestr(out, "-----BEGIN PGP SIGNED MESSAGE-----" LF ); for( sk_rover = sk_list; sk_rover; sk_rover = sk_rover->next ) { PKT_secret_key *sk = sk_rover->sk; if( hash_for(sk) == DIGEST_ALGO_MD5 ) only_md5 = 1; else { only_md5 = 0; break; } } if( !(old_style && only_md5) ) { const char *s; int any = 0; byte hashs_seen[256]; memset( hashs_seen, 0, sizeof hashs_seen ); iobuf_writestr(out, "Hash: " ); for( sk_rover = sk_list; sk_rover; sk_rover = sk_rover->next ) { PKT_secret_key *sk = sk_rover->sk; int i = hash_for(sk); if( !hashs_seen[ i & 0xff ] ) { s = gcry_md_algo_name ( i ); if( s ) { hashs_seen[ i & 0xff ] = 1; if( any ) iobuf_put(out, ',' ); iobuf_writestr(out, s ); any = 1; } } } assert(any); iobuf_writestr(out, LF ); } if( opt.not_dash_escaped ) iobuf_writestr( out, "NotDashEscaped: You need GnuPG to verify this message" LF ); iobuf_writestr(out, LF ); if ( gcry_md_open (&textmd, 0, 0) ) BUG (); for( sk_rover = sk_list; sk_rover; sk_rover = sk_rover->next ) { PKT_secret_key *sk = sk_rover->sk; gcry_md_enable (textmd, hash_for(sk)); } if ( DBG_HASHING ) gcry_md_start_debug ( textmd, "clearsign" ); copy_clearsig_text( out, inp, textmd, !opt.not_dash_escaped, opt.escape_from, (old_style && only_md5) ); /* fixme: check for read errors */ /* now write the armor */ afx->what = 2; push_armor_filter (afx, out); /* write the signatures */ rc=write_signature_packets (sk_list, out, textmd, 0x01, 0, duration, 'C'); if( rc ) goto leave; leave: if( rc ) iobuf_cancel(out); else iobuf_close(out); iobuf_close(inp); gcry_md_close ( textmd ); release_sk_list( sk_list ); release_progress_context (pfx); release_armor_context (afx); return rc; } /* * Sign and conventionally encrypt the given file. * FIXME: Far too much code is duplicated - revamp the whole file. */ int sign_symencrypt_file (const char *fname, strlist_t locusr) { armor_filter_context_t *afx; progress_filter_context_t *pfx; compress_filter_context_t zfx; md_filter_context_t mfx; text_filter_context_t tfx; cipher_filter_context_t cfx; IOBUF inp = NULL, out = NULL; PACKET pkt; STRING2KEY *s2k = NULL; int rc = 0; SK_LIST sk_list = NULL; SK_LIST sk_rover = NULL; int algo; u32 duration=0; int canceled; pfx = new_progress_context (); afx = new_armor_context (); memset( &zfx, 0, sizeof zfx); memset( &mfx, 0, sizeof mfx); memset( &tfx, 0, sizeof tfx); memset( &cfx, 0, sizeof cfx); init_packet( &pkt ); if(!opt.force_v3_sigs && !RFC1991) { if(opt.ask_sig_expire && !opt.batch) duration=ask_expire_interval(1,opt.def_sig_expire); else duration=parse_expire_string(opt.def_sig_expire); } rc = build_sk_list (locusr, &sk_list, 1, PUBKEY_USAGE_SIG); if (rc) goto leave; /* prepare iobufs */ inp = iobuf_open(fname); if (inp && is_secured_file (iobuf_get_fd (inp))) { iobuf_close (inp); inp = NULL; errno = EPERM; } if( !inp ) { rc = gpg_error_from_syserror (); log_error (_("can't open `%s': %s\n"), fname? fname: "[stdin]", strerror(errno) ); goto leave; } handle_progress (pfx, inp, fname); /* prepare key */ s2k = xmalloc_clear( sizeof *s2k ); s2k->mode = RFC1991? 0:opt.s2k_mode; s2k->hash_algo = S2K_DIGEST_ALGO; algo = default_cipher_algo(); if (!opt.quiet || !opt.batch) log_info (_("%s encryption will be used\n"), gcry_cipher_algo_name (algo) ); cfx.dek = passphrase_to_dek( NULL, 0, algo, s2k, 2, NULL, &canceled); if (!cfx.dek || !cfx.dek->keylen) { rc = gpg_error (canceled?GPG_ERR_CANCELED:GPG_ERR_BAD_PASSPHRASE); log_error(_("error creating passphrase: %s\n"), gpg_strerror (rc) ); goto leave; } /* We have no way to tell if the recipient can handle messages with an MDC, so this defaults to no. Perhaps in a few years, this can be defaulted to yes. Note that like regular encrypting, --force-mdc overrides --disable-mdc. */ if(opt.force_mdc) cfx.dek->use_mdc=1; /* now create the outfile */ rc = open_outfile (fname, opt.armor? 1:0, &out); if (rc) goto leave; /* prepare to calculate the MD over the input */ if (opt.textmode) iobuf_push_filter (inp, text_filter, &tfx); if ( gcry_md_open (&mfx.md, 0, 0) ) BUG (); if ( DBG_HASHING ) gcry_md_start_debug (mfx.md, "symc-sign"); for (sk_rover = sk_list; sk_rover; sk_rover = sk_rover->next) { PKT_secret_key *sk = sk_rover->sk; gcry_md_enable (mfx.md, hash_for (sk)); } iobuf_push_filter (inp, md_filter, &mfx); /* Push armor output filter */ if (opt.armor) push_armor_filter (afx, out); /* Write the symmetric key packet */ /*(current filters: armor)*/ if (!RFC1991) { PKT_symkey_enc *enc = xmalloc_clear( sizeof *enc ); enc->version = 4; enc->cipher_algo = cfx.dek->algo; enc->s2k = *s2k; pkt.pkttype = PKT_SYMKEY_ENC; pkt.pkt.symkey_enc = enc; if( (rc = build_packet( out, &pkt )) ) log_error("build symkey packet failed: %s\n", g10_errstr(rc) ); xfree(enc); } /* Push the encryption filter */ iobuf_push_filter( out, cipher_filter, &cfx ); /* Push the compress filter */ if (default_compress_algo()) push_compress_filter(out,&zfx,default_compress_algo()); /* Write the one-pass signature packets */ /*(current filters: zip - encrypt - armor)*/ if (!RFC1991) { rc = write_onepass_sig_packets (sk_list, out, opt.textmode? 0x01:0x00); if (rc) goto leave; } write_status_begin_signing (mfx.md); /* Pipe data through all filters; i.e. write the signed stuff */ /*(current filters: zip - encrypt - armor)*/ rc = write_plaintext_packet (out, inp, fname, opt.textmode ? 't':'b'); if (rc) goto leave; /* Write the signatures */ /*(current filters: zip - encrypt - armor)*/ rc = write_signature_packets (sk_list, out, mfx.md, opt.textmode? 0x01 : 0x00, 0, duration, 'S'); if( rc ) goto leave; leave: if( rc ) iobuf_cancel(out); else { iobuf_close(out); write_status( STATUS_END_ENCRYPTION ); } iobuf_close(inp); release_sk_list( sk_list ); gcry_md_close( mfx.md ); xfree(cfx.dek); xfree(s2k); release_progress_context (pfx); release_armor_context (afx); return rc; } /**************** * Create a signature packet for the given public key certificate and * the user id and return it in ret_sig. User signature class SIGCLASS * user-id is not used (and may be NULL if sigclass is 0x20) If * DIGEST_ALGO is 0 the function selects an appropriate one. * SIGVERSION gives the minimal required signature packet version; * this is needed so that special properties like local sign are not * applied (actually: dropped) when a v3 key is used. TIMESTAMP is * the timestamp to use for the signature. 0 means "now" */ int make_keysig_packet( PKT_signature **ret_sig, PKT_public_key *pk, PKT_user_id *uid, PKT_public_key *subpk, PKT_secret_key *sk, int sigclass, int digest_algo, int sigversion, u32 timestamp, u32 duration, int (*mksubpkt)(PKT_signature *, void *), void *opaque ) { PKT_signature *sig; int rc=0; gcry_md_hd_t md; assert( (sigclass >= 0x10 && sigclass <= 0x13) || sigclass == 0x1F || sigclass == 0x20 || sigclass == 0x18 || sigclass == 0x19 || sigclass == 0x30 || sigclass == 0x28 ); if (opt.force_v4_certs) sigversion = 4; if (sigversion < sk->version) sigversion = sk->version; /* If you are making a signature on a v4 key using your v3 key, it doesn't make sense to generate a v3 sig. After all, no v3-only PGP implementation could understand the v4 key in the first place. Note that this implies that a signature on an attribute uid is usually going to be v4 as well, since they are not generally found on v3 keys. */ if (sigversion < pk->version) sigversion = pk->version; if( !digest_algo ) { /* Basically, this means use SHA1 always unless it's a v3 RSA key making a v3 cert (use MD5), or the user specified something (use whatever they said), or it's DSA (use the best match). They still can't pick an inappropriate hash for DSA or the signature will fail. Note that this still allows the caller of make_keysig_packet to override the user setting if it must. */ if(opt.cert_digest_algo) digest_algo=opt.cert_digest_algo; else if(sk->pubkey_algo==PUBKEY_ALGO_RSA && pk->version<4 && sigversion<4) digest_algo = DIGEST_ALGO_MD5; else if(sk->pubkey_algo==PUBKEY_ALGO_DSA) digest_algo = match_dsa_hash (gcry_mpi_get_nbits (sk->skey[1])/8); else digest_algo = DIGEST_ALGO_SHA1; } if ( gcry_md_open (&md, digest_algo, 0 ) ) BUG (); /* Hash the public key certificate. */ hash_public_key( md, pk ); if( sigclass == 0x18 || sigclass == 0x19 || sigclass == 0x28 ) { /* hash the subkey binding/backsig/revocation */ hash_public_key( md, subpk ); } else if( sigclass != 0x1F && sigclass != 0x20 ) { /* hash the user id */ hash_uid (md, sigversion, uid); } /* and make the signature packet */ sig = xmalloc_clear( sizeof *sig ); sig->version = sigversion; sig->flags.exportable=1; sig->flags.revocable=1; keyid_from_sk( sk, sig->keyid ); sig->pubkey_algo = sk->pubkey_algo; sig->digest_algo = digest_algo; if(timestamp) sig->timestamp=timestamp; else sig->timestamp=make_timestamp(); if(duration) sig->expiredate=sig->timestamp+duration; sig->sig_class = sigclass; if( sig->version >= 4 ) build_sig_subpkt_from_sig( sig ); mk_notation_policy_etc( sig, pk, sk ); /* Crucial that the call to mksubpkt comes LAST before the calls to finalize the sig as that makes it possible for the mksubpkt function to get a reliable pointer to the subpacket area. */ if( sig->version >= 4 && mksubpkt ) rc = (*mksubpkt)( sig, opaque ); if( !rc ) { hash_sigversion_to_magic (md, sig); gcry_md_final (md); rc = complete_sig( sig, sk, md ); } gcry_md_close ( md ); if( rc ) free_seckey_enc( sig ); else *ret_sig = sig; return rc; } /**************** * Create a new signature packet based on an existing one. * Only user ID signatures are supported for now. * TODO: Merge this with make_keysig_packet. */ int update_keysig_packet( PKT_signature **ret_sig, PKT_signature *orig_sig, PKT_public_key *pk, PKT_user_id *uid, PKT_public_key *subpk, PKT_secret_key *sk, int (*mksubpkt)(PKT_signature *, void *), void *opaque ) { PKT_signature *sig; int rc=0; gcry_md_hd_t md; if ((!orig_sig || !pk || !sk) || (orig_sig->sig_class >= 0x10 && orig_sig->sig_class <= 0x13 && !uid) || (orig_sig->sig_class == 0x18 && !subpk)) return G10ERR_GENERAL; if ( gcry_md_open (&md, orig_sig->digest_algo, 0 ) ) BUG (); /* Hash the public key certificate and the user id. */ hash_public_key( md, pk ); if( orig_sig->sig_class == 0x18 ) hash_public_key( md, subpk ); else hash_uid (md, orig_sig->version, uid); /* create a new signature packet */ sig = copy_signature (NULL, orig_sig); /* We need to create a new timestamp so that new sig expiration calculations are done correctly... */ sig->timestamp=make_timestamp(); /* ... but we won't make a timestamp earlier than the existing one. */ while(sig->timestamp<=orig_sig->timestamp) { gnupg_sleep (1); sig->timestamp=make_timestamp(); } /* Note that already expired sigs will remain expired (with a duration of 1) since build-packet.c:build_sig_subpkt_from_sig detects this case. */ if( sig->version >= 4 ) { /* Put the updated timestamp into the sig. Note that this will automagically lower any sig expiration dates to correctly correspond to the differences in the timestamps (i.e. the duration will shrink). */ build_sig_subpkt_from_sig( sig ); if (mksubpkt) rc = (*mksubpkt)(sig, opaque); } if (!rc) { hash_sigversion_to_magic (md, sig); gcry_md_final (md); rc = complete_sig( sig, sk, md ); } gcry_md_close (md); if( rc ) free_seckey_enc (sig); else *ret_sig = sig; return rc; }