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gnupg/g10/sign.c
David Shaw fd08b13528 * sign.c (hash_for, sign_file): When encrypting and signing at the same 
time, consult the various hash prefs to pick a hash algorithm to use.
Pass in a 160-bit hint if any of the signing keys are DSA.

* keydb.h, pkclist.c (select_algo_from_prefs, algo_available): Pass a
"hints" opaque pointer in to let the caller give hints as to what
algorithms would be acceptable.  The only current hint is for
PREFTYPE_HASH to require a 160-bit hash for DSA.  Change all callers in
encode.c (encode_crypt, encrypt_filter) and sign.c (sign_file).  If we
settle on MD5 as the best algorithm based solely on recepient keys and
SHA1 is also a possibility, use SHA1 unless the user intentionally chose
MD5.  This is as per 2440:13.

* exec.c (make_tempdir): Fix duplicated filename problem.
2002-06-04 23:18:37 +00:00

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/* sign.c - sign data
* Copyright (C) 1998, 1999, 2000, 2001, 2002 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 2 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, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
*/
#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <assert.h>
#include <unistd.h> /* need sleep() */
#include "options.h"
#include "packet.h"
#include "errors.h"
#include "iobuf.h"
#include "keydb.h"
#include "memory.h"
#include "util.h"
#include "main.h"
#include "filter.h"
#include "ttyio.h"
#include "trustdb.h"
#include "status.h"
#include "i18n.h"
#ifdef HAVE_DOSISH_SYSTEM
#define LF "\r\n"
void __stdcall Sleep(ulong);
#define sleep(a) Sleep((a)*1000)
#else
#define LF "\n"
#endif
static int recipient_digest_algo=0;
/****************
* Create a notation. 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_and_policy( PKT_signature *sig,
PKT_public_key *pk, PKT_secret_key *sk )
{
const char *string;
char *s=NULL;
byte *buf;
unsigned n1, n2;
STRLIST nd=NULL,pu=NULL;
struct expando_args args;
memset(&args,0,sizeof(args));
args.pk=pk;
args.sk=sk;
/* notation data */
if(IS_SIG(sig) && opt.sig_notation_data)
{
if(sig->version<4)
log_info("can't put notation data into v3 signatures\n");
else
nd=opt.sig_notation_data;
}
else if( IS_CERT(sig) && opt.cert_notation_data )
{
if(sig->version<4)
log_info("can't put notation data into v3 key signatures\n");
else
nd=opt.cert_notation_data;
}
for( ; nd; nd = nd->next ) {
char *expanded;
string = nd->d;
s = strchr( string, '=' );
if( !s )
BUG(); /* we have already parsed this */
n1 = s - string;
s++;
expanded=pct_expando(s,&args);
if(!expanded)
{
log_error(_("WARNING: unable to %%-expand notation "
"(too large). Using unexpanded.\n"));
expanded=m_strdup(s);
}
n2 = strlen(expanded);
buf = m_alloc( 8 + n1 + n2 );
buf[0] = 0x80; /* human readable */
buf[1] = buf[2] = buf[3] = 0;
buf[4] = n1 >> 8;
buf[5] = n1;
buf[6] = n2 >> 8;
buf[7] = n2;
memcpy(buf+8, string, n1 );
memcpy(buf+8+n1, expanded, n2 );
build_sig_subpkt( sig, SIGSUBPKT_NOTATION
| ((nd->flags & 1)? SIGSUBPKT_FLAG_CRITICAL:0),
buf, 8+n1+n2 );
m_free(expanded);
m_free(buf);
}
if(opt.show_notation)
show_notation(sig,0);
/* set policy URL */
if( IS_SIG(sig) && opt.sig_policy_url )
{
if(sig->version<4)
log_info("can't put a policy URL into v3 signatures\n");
else
pu=opt.sig_policy_url;
}
else if( IS_CERT(sig) && opt.cert_policy_url )
{
if(sig->version<4)
log_info("can't put a policy URL into v3 key 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=m_strdup(string);
}
build_sig_subpkt(sig,SIGSUBPKT_POLICY|
((pu->flags & 1)?SIGSUBPKT_FLAG_CRITICAL:0),
s,strlen(s));
m_free(s);
}
if(opt.show_policy_url)
show_policy_url(sig,0);
}
/*
* Helper to hash a user ID packet.
*/
static void
hash_uid (MD_HANDLE 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;
}
md_write( md, buf, 5 );
}
if(uid->attrib_data)
md_write (md, uid->attrib_data, uid->attrib_len );
else
md_write (md, uid->name, uid->len );
}
/*
* Helper to hash some parts from the signature
*/
static void
hash_sigversion_to_magic (MD_HANDLE md, const PKT_signature *sig)
{
if (sig->version >= 4)
md_putc (md, sig->version);
md_putc (md, sig->sig_class);
if (sig->version < 4) {
u32 a = sig->timestamp;
md_putc (md, (a >> 24) & 0xff );
md_putc (md, (a >> 16) & 0xff );
md_putc (md, (a >> 8) & 0xff );
md_putc (md, a & 0xff );
}
else {
byte buf[6];
size_t n;
md_putc (md, sig->pubkey_algo);
md_putc (md, sig->digest_algo);
if (sig->hashed) {
n = sig->hashed->len;
md_putc (md, (n >> 8) );
md_putc (md, n );
md_write (md, sig->hashed->data, n );
n += 6;
}
else {
md_putc (md, 0); /* always hash the length of the subpacket*/
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;
md_write (md, buf, 6);
}
}
static int
do_sign( PKT_secret_key *sk, PKT_signature *sig,
MD_HANDLE md, int digest_algo )
{
MPI 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 = md_get_algo(md);
print_digest_algo_note( digest_algo );
dp = md_read( md, digest_algo );
sig->digest_algo = digest_algo;
sig->digest_start[0] = dp[0];
sig->digest_start[1] = dp[1];
frame = encode_md_value( sk->pubkey_algo, md,
digest_algo, mpi_get_nbits(sk->skey[0]), 0 );
if (!frame)
return G10ERR_GENERAL;
rc = pubkey_sign( sk->pubkey_algo, sig->data, frame, sk->skey );
mpi_free(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 = m_alloc_clear (sizeof *pk);
if( get_pubkey( pk, sig->keyid ) )
rc = G10ERR_NO_PUBKEY;
else {
frame = encode_md_value (pk->pubkey_algo, md,
sig->digest_algo,
mpi_get_nbits(pk->pkey[0]), 0);
if (!frame)
rc = G10ERR_GENERAL;
else
rc = pubkey_verify (pk->pubkey_algo, frame,
sig->data, pk->pkey,
NULL, NULL );
mpi_free (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( sig->keyid );
log_info(_("%s signature from: %s\n"),
pubkey_algo_to_string(sk->pubkey_algo), ustr );
m_free(ustr);
}
}
return rc;
}
int
complete_sig( PKT_signature *sig, PKT_secret_key *sk, MD_HANDLE md )
{
int rc=0;
if( !(rc=check_secret_key( sk, 0 )) )
rc = do_sign( sk, sig, md, 0 );
return rc;
}
static int
hash_for(int pubkey_algo, int packet_version )
{
if( opt.def_digest_algo )
return opt.def_digest_algo;
if( recipient_digest_algo )
return recipient_digest_algo;
if( pubkey_algo == PUBKEY_ALGO_DSA )
return DIGEST_ALGO_SHA1;
if( pubkey_algo == PUBKEY_ALGO_RSA && packet_version < 4 )
return DIGEST_ALGO_MD5;
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 = m_alloc_clear (sizeof *ops);
ops->sig_class = sigclass;
ops->digest_algo = hash_for (sk->pubkey_algo, sk->version);
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) {
if (fname || opt.set_filename) {
char *s = make_basename (opt.set_filename? opt.set_filename
: fname);
pt = m_alloc (sizeof *pt + strlen(s) - 1);
pt->namelen = strlen (s);
memcpy (pt->name, s, pt->namelen);
m_free (s);
}
else { /* no filename */
pt = m_alloc (sizeof *pt - 1);
pt->namelen = 0;
}
}
/* try to calculate the length of the data */
if (fname) {
if( !(filesize = iobuf_get_filelength(inp)) )
log_info (_("WARNING: `%s' is an empty file\n"), fname);
/* we can't yet encode the length of very large files,
* so we switch to partial length encoding in this case */
if (filesize >= IOBUF_FILELENGTH_LIMIT)
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 && !opt.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 (iobuf_write(out, copy_buffer, bytes_copied) == -1) {
rc = G10ERR_WRITE_FILE;
log_error ("copying input to output failed: %s\n",
g10_errstr(rc));
break;
}
memset(copy_buffer, 0, 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, MD_HANDLE 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;
MD_HANDLE md;
int rc;
sk = sk_rover->sk;
/* build the signature packet */
sig = m_alloc_clear (sizeof *sig);
if(opt.force_v3_sigs || opt.rfc1991)
sig->version=3;
else if(duration || opt.sig_policy_url || opt.sig_notation_data)
sig->version=4;
else
sig->version=sk->version;
keyid_from_sk (sk, sig->keyid);
sig->digest_algo = hash_for (sk->pubkey_algo, sk->version);
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;
md = md_copy (hash);
if (sig->version >= 4)
build_sig_subpkt_from_sig (sig);
mk_notation_and_policy (sig, NULL, sk);
hash_sigversion_to_magic (md, sig);
md_final (md);
rc = do_sign( sk, sig, md, hash_for (sig->pubkey_algo, sk->version) );
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 filenames, int detached, STRLIST locusr,
int encryptflag, STRLIST 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;
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 timestamp=0,duration=0;
memset( &afx, 0, sizeof afx);
memset( &zfx, 0, sizeof zfx);
memset( &mfx, 0, sizeof mfx);
memset( &tfx, 0, sizeof tfx);
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(opt.ask_sig_expire && !opt.force_v3_sigs && !opt.batch && !opt.rfc1991)
duration=ask_expire_interval(1);
if( (rc=build_sk_list( locusr, &sk_list, 1, PUBKEY_USAGE_SIG )) )
goto leave;
if(opt.pgp2 && !only_old_style(sk_list))
{
log_info(_("you can only detach-sign with PGP 2.x style keys "
"while in --pgp2 mode\n"));
log_info(_("this message may not be usable by PGP 2.x\n"));
opt.pgp2=0;
}
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 if( !(inp = iobuf_open(fname)) ) {
log_error("can't open %s: %s\n", fname? fname: "[stdin]",
strerror(errno) );
rc = G10ERR_OPEN_FILE;
goto leave;
}
if( outfile ) {
if( !(out = iobuf_create( outfile )) ) {
log_error(_("can't create %s: %s\n"), outfile, strerror(errno) );
rc = G10ERR_CREATE_FILE;
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 )
iobuf_push_filter( inp, text_filter, &tfx );
mfx.md = md_open(0, 0);
/* If we're encrypting and signing, it is reasonable to pick the
hash algorithm to use out of the recepient key prefs. */
if(pk_list && !opt.def_digest_algo)
{
int hashlen=0,algo;
/* Of course, if the recipient asks for something unreasonable
(like a non-160-bit hash for DSA, for example), then don't
do it. Check all sk's - if any are DSA, then the hash must
be 160-bit. In the future this can be more complex with
different hashes for each sk, but so long as there is only
one signing algorithm with hash restrictions, this is
ok. -dms */
for( sk_rover = sk_list; sk_rover; sk_rover = sk_rover->next )
if(sk_rover->sk->pubkey_algo==PUBKEY_ALGO_DSA)
hashlen=20;
if((algo=select_algo_from_prefs(pk_list,PREFTYPE_HASH,&hashlen))>0)
recipient_digest_algo=algo;
}
for( sk_rover = sk_list; sk_rover; sk_rover = sk_rover->next ) {
PKT_secret_key *sk = sk_rover->sk;
md_enable(mfx.md, hash_for(sk->pubkey_algo, sk->version ));
}
if( !multifile )
iobuf_push_filter( inp, md_filter, &mfx );
if( detached && !encryptflag && !opt.rfc1991 )
afx.what = 2;
if( opt.armor && !outfile )
iobuf_push_filter( out, armor_filter, &afx );
if( encryptflag ) {
efx.pk_list = pk_list;
/* fixme: set efx.cfx.datalen if known */
iobuf_push_filter( out, encrypt_filter, &efx );
}
if( opt.compress && !outfile && ( !detached || opt.compress_sigs) )
{
int compr_algo=opt.def_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,NULL))==-1)
compr_algo=DEFAULT_COMPRESS_ALGO;
}
/* algo 0 means no compression */
if( compr_algo )
{
zfx.algo = compr_algo;
iobuf_push_filter( out, compress_filter, &zfx );
}
}
/* Write the one-pass signature packets if needed */
if (!detached && !opt.rfc1991) {
rc = write_onepass_sig_packets (sk_list, out,
opt.textmode && !outfile ? 0x01:0x00);
if (rc)
goto leave;
}
/* setup the inner packet */
if( detached ) {
if( multifile ) {
STRLIST sl;
if( opt.verbose )
log_info(_("signing:") );
/* must walk reverse trough this list */
for( sl = strlist_last(filenames); sl;
sl = strlist_prev( filenames, sl ) ) {
if( !(inp = iobuf_open(sl->d)) ) {
log_error(_("can't open %s: %s\n"),
sl->d, strerror(errno) );
rc = G10ERR_OPEN_FILE;
goto leave;
}
if( opt.verbose )
fprintf(stderr, " `%s'", sl->d );
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,
timestamp, 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);
md_close( mfx.md );
release_sk_list( sk_list );
release_pk_list( pk_list );
recipient_digest_algo=0;
return rc;
}
/****************
* make a clear signature. note that opt.armor is not needed
*/
int
clearsign_file( const char *fname, STRLIST locusr, const char *outfile )
{
armor_filter_context_t afx;
MD_HANDLE 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 = opt.rfc1991;
int only_md5 = 0;
u32 timestamp=0,duration=0;
memset( &afx, 0, sizeof afx);
init_packet( &pkt );
if(opt.ask_sig_expire && !opt.force_v3_sigs && !opt.batch && !opt.rfc1991)
duration=ask_expire_interval(1);
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(!old_style && opt.pgp2)
{
log_info(_("you can only clearsign with PGP 2.x style keys "
"while in --pgp2 mode\n"));
log_info(_("this message may not be usable by PGP 2.x\n"));
opt.pgp2=0;
}
/* prepare iobufs */
if( !(inp = iobuf_open(fname)) ) {
log_error("can't open %s: %s\n", fname? fname: "[stdin]",
strerror(errno) );
rc = G10ERR_OPEN_FILE;
goto leave;
}
if( outfile ) {
if( !(out = iobuf_create( outfile )) ) {
log_error(_("can't create %s: %s\n"), outfile, strerror(errno) );
rc = G10ERR_CREATE_FILE;
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->pubkey_algo, sk->version) == 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->pubkey_algo, sk->version);
if( !hashs_seen[ i & 0xff ] ) {
s = digest_algo_to_string( 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 );
textmd = md_open(0, 0);
for( sk_rover = sk_list; sk_rover; sk_rover = sk_rover->next ) {
PKT_secret_key *sk = sk_rover->sk;
md_enable(textmd, hash_for(sk->pubkey_algo, sk->version));
}
if ( DBG_HASHING )
md_start_debug( textmd, "clearsign" );
copy_clearsig_text( out, inp, textmd,
!opt.not_dash_escaped, opt.escape_from, old_style );
/* fixme: check for read errors */
/* now write the armor */
afx.what = 2;
iobuf_push_filter( out, armor_filter, &afx );
/* write the signatures */
rc = write_signature_packets (sk_list, out, textmd, 0x01,
timestamp, duration, 'C');
if( rc )
goto leave;
leave:
if( rc )
iobuf_cancel(out);
else
iobuf_close(out);
iobuf_close(inp);
md_close( textmd );
release_sk_list( sk_list );
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 locusr)
{
armor_filter_context_t afx;
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 timestamp=0,duration=0;
memset( &afx, 0, sizeof afx);
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.ask_sig_expire && !opt.force_v3_sigs && !opt.batch && !opt.rfc1991)
duration=ask_expire_interval(1);
rc = build_sk_list (locusr, &sk_list, 1, PUBKEY_USAGE_SIG);
if (rc)
goto leave;
/* prepare iobufs */
inp = iobuf_open(fname);
if( !inp ) {
log_error("can't open %s: %s\n", fname? fname: "[stdin]",
strerror(errno) );
rc = G10ERR_OPEN_FILE;
goto leave;
}
/* prepare key */
s2k = m_alloc_clear( sizeof *s2k );
s2k->mode = opt.rfc1991? 0:opt.s2k_mode;
s2k->hash_algo = opt.def_digest_algo ? opt.def_digest_algo
: opt.s2k_digest_algo;
algo = opt.def_cipher_algo ? opt.def_cipher_algo : opt.s2k_cipher_algo;
if (!opt.quiet || !opt.batch)
log_info (_("%s encryption will be used\n"),
cipher_algo_to_string(algo) );
cfx.dek = passphrase_to_dek( NULL, 0, algo, s2k, 2, NULL );
if (!cfx.dek || !cfx.dek->keylen) {
rc = G10ERR_PASSPHRASE;
log_error(_("error creating passphrase: %s\n"), g10_errstr(rc) );
goto leave;
}
/* 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);
mfx.md = md_open(0, 0);
for (sk_rover = sk_list; sk_rover; sk_rover = sk_rover->next) {
PKT_secret_key *sk = sk_rover->sk;
md_enable (mfx.md, hash_for (sk->pubkey_algo, sk->version ));
}
iobuf_push_filter (inp, md_filter, &mfx);
/* Push armor output filter */
if (opt.armor)
iobuf_push_filter (out, armor_filter, &afx);
/* Write the symmetric key packet */
/*(current filters: armor)*/
if (!opt.rfc1991) {
PKT_symkey_enc *enc = m_alloc_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) );
m_free(enc);
}
/* Push the encryption filter */
iobuf_push_filter( out, cipher_filter, &cfx );
/* Push the Zip filter */
if (opt.compress)
{
int compr_algo=opt.def_compress_algo;
/* Default */
if(compr_algo==-1)
compr_algo=DEFAULT_COMPRESS_ALGO;
if (compr_algo)
{
zfx.algo = compr_algo;
iobuf_push_filter( out, compress_filter, &zfx );
}
}
/* Write the one-pass signature packets */
/*(current filters: zip - encrypt - armor)*/
if (!opt.rfc1991) {
rc = write_onepass_sig_packets (sk_list, out,
opt.textmode? 0x01:0x00);
if (rc)
goto leave;
}
/* 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,
timestamp, 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 );
md_close( mfx.md );
m_free(cfx.dek);
m_free(s2k);
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;
MD_HANDLE md;
assert( (sigclass >= 0x10 && sigclass <= 0x13) || sigclass == 0x1F
|| sigclass == 0x20 || sigclass == 0x18
|| 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. */
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). They still must use a
160-bit hash with 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 ||
sk->pubkey_algo==PUBKEY_ALGO_RSA_S) &&
pk->version<4 && sigversion < 4)
digest_algo = DIGEST_ALGO_MD5;
else
digest_algo = DIGEST_ALGO_SHA1;
}
md = md_open( digest_algo, 0 );
/* hash the public key certificate and the user id */
hash_public_key( md, pk );
if( sigclass == 0x18 || sigclass == 0x28 ) { /* subkey binding/revocation*/
hash_public_key( md, subpk );
}
else if( sigclass != 0x1F && sigclass != 0x20 ) {
hash_uid (md, sigversion, uid);
}
/* and make the signature packet */
sig = m_alloc_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 );
if( sig->version >= 4 && mksubpkt )
rc = (*mksubpkt)( sig, opaque );
if( !rc ) {
mk_notation_and_policy( sig, pk, sk );
hash_sigversion_to_magic (md, sig);
md_final(md);
rc = complete_sig( sig, sk, md );
}
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_secret_key *sk,
int (*mksubpkt)(PKT_signature *, void *),
void *opaque
)
{
PKT_signature *sig;
int rc=0;
MD_HANDLE md;
if (!orig_sig || !pk || !uid || !sk)
return G10ERR_GENERAL;
if (orig_sig->sig_class < 0x10 || orig_sig->sig_class > 0x13 )
return G10ERR_GENERAL;
md = md_open( orig_sig->digest_algo, 0 );
/* hash the public key certificate and the user id */
hash_public_key( md, pk );
hash_uid (md, orig_sig->version, uid);
/* create a new signature packet */
sig = copy_signature (NULL, orig_sig);
if ( sig->version >= 4 && mksubpkt)
rc = (*mksubpkt)(sig, opaque);
/* we increase the timestamp by one second so that a future import
of this key will replace the existing one. We also make sure that
we don't create a timestamp in the future */
sig->timestamp++;
while (sig->timestamp >= make_timestamp())
sleep (1);
/* put the updated timestamp back into the data */
if( sig->version >= 4 )
build_sig_subpkt_from_sig( sig );
if (!rc) {
hash_sigversion_to_magic (md, sig);
md_final(md);
rc = complete_sig( sig, sk, md );
}
md_close (md);
if( rc )
free_seckey_enc (sig);
else
*ret_sig = sig;
return rc;
}
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