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gpg: Detect already compressed data also when using a pipe.

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* common/iobuf.c (file_filter_ctx_t): Add fields for the peek feature.
(file_filter): Implement peeking.
(iobuf_ioctl): Add new IOBUF_IOCTL_PEEK.
* common/iobuf.h (IOBUF_IOCTL_PEEK, IOBUFCTRL_PEEK): New.
* common/miscellaneous.c (is_file_compressed): Rewrite.  Detect PDF.
* g10/encrypt.c (encrypt_simple): Peek before detecting compression.
(encrypt_crypt): Ditto.
* g10/sign.c (sign_file): Also detect already compressed data.

* g10/options.h (opt): Add explicit_compress_option.
* g10/gpg.c (main): Set opt.explicit_compress_option for -z.

--

Note that this patch also introduces a compression check for signing
which was never done in the past.

GnuPG-bug-id: 6332
Backported-from-master: 60963d98cf

Note that sign.c (sign_file) has been re-indented to ease future
backports.
This commit is contained in:
Werner Koch 2023-01-18 18:04:50 +01:00
parent ca822a2339
commit ce8ffd71b7
No known key found for this signature in database
GPG key ID: E3FDFF218E45B72B
9 changed files with 491 additions and 347 deletions
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606
g10/sign.c
View file

@ -921,62 +921,68 @@ int
sign_file (ctrl_t ctrl, 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;
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_t inp = NULL;
iobuf_t 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;
char peekbuf[32];
int peekbuflen = 0;
pfx = new_progress_context ();
afx = new_armor_context ();
memset( &zfx, 0, sizeof zfx);
memset( &mfx, 0, sizeof mfx);
memset( &efx, 0, sizeof efx);
efx.ctrl = ctrl;
init_packet( &pkt );
if( filenames ) {
fname = filenames->d;
multifile = !!filenames->next;
pfx = new_progress_context ();
afx = new_armor_context ();
memset (&zfx, 0, sizeof zfx);
memset (&mfx, 0, sizeof mfx);
memset (&efx, 0, sizeof efx);
efx.ctrl = ctrl;
init_packet (&pkt);
if (filenames)
{
fname = filenames->d;
multifile = !!filenames->next;
}
else
fname = NULL;
else
fname = NULL;
if( fname && filenames->next && (!detached || encryptflag) )
log_bug("multiple files can only be detached signed");
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 (encryptflag == 2
&& (rc = setup_symkey (&efx.symkey_s2k,&efx.symkey_dek)))
goto leave;
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 (opt.ask_sig_expire && !opt.batch)
duration = ask_expire_interval(1,opt.def_sig_expire);
else
duration = parse_expire_string(opt.def_sig_expire);
/* Note: In the old non-agent version the following call used to
unprotect the secret key. This is now done on demand by the agent. */
if( (rc = build_sk_list (ctrl, locusr, &sk_list, PUBKEY_USAGE_SIG )) )
goto leave;
/* Note: In the old non-agent version the following call used to
unprotect the secret key. This is now done on demand by the agent. */
if ((rc = build_sk_list (ctrl, locusr, &sk_list, PUBKEY_USAGE_SIG )))
goto leave;
if (encryptflag
&& (rc=build_pk_list (ctrl, remusr, &pk_list)))
goto leave;
if (encryptflag
&& (rc=build_pk_list (ctrl, remusr, &pk_list)))
goto leave;
/* prepare iobufs */
if( multifile ) /* have list of filenames */
inp = NULL; /* we do it later */
else {
/* 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)))
{
@ -992,274 +998,298 @@ sign_file (ctrl_t ctrl, strlist_t filenames, int detached, strlist_t locusr,
goto leave;
}
handle_progress (pfx, inp, fname);
}
if( outfile ) {
if (is_secured_filename ( outfile )) {
out = NULL;
gpg_err_set_errno (EPERM);
peekbuflen = iobuf_ioctl (inp, IOBUF_IOCTL_PEEK, sizeof peekbuf, peekbuf);
if (peekbuflen < 0)
{
peekbuflen = 0;
if (DBG_FILTER)
log_debug ("peeking at input failed\n");
}
else
out = iobuf_create (outfile, 0);
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 );
handle_progress (pfx, inp, fname);
}
else if( (rc = open_outfile (-1, fname,
opt.armor? 1: detached? 2:0, 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 (outfile)
{
if (is_secured_filename ( outfile ))
{
out = NULL;
gpg_err_set_errno (EPERM);
}
else
out = iobuf_create (outfile, 0);
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 (-1, fname,
opt.armor? 1: detached? 2:0, 0, &out)))
goto leave;
if ( gcry_md_open (&mfx.md, 0, 0) )
BUG ();
if (DBG_HASHING)
gcry_md_debug (mfx.md, "sign");
/* 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 we're encrypting and signing, it is reasonable to pick the
hash algorithm to use out of the recipient 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;
int conflict = 0;
struct pref_hint hint = { 0 };
if (gcry_md_open (&mfx.md, 0, 0))
BUG ();
if (DBG_HASHING)
gcry_md_debug (mfx.md, "sign");
/* 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. */
/* If we're encrypting and signing, it is reasonable to pick the
* hash algorithm to use out of the recipient 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;
int conflict = 0;
struct pref_hint hint = { 0 };
for (sk_rover = sk_list; sk_rover; sk_rover = sk_rover->next )
{
if (sk_rover->pk->pubkey_algo == PUBKEY_ALGO_DSA
|| sk_rover->pk->pubkey_algo == PUBKEY_ALGO_ECDSA)
{
int temp_hashlen = (gcry_mpi_get_nbits
(sk_rover->pk->pkey[1]));
/* 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->pk->pubkey_algo == PUBKEY_ALGO_DSA
|| sk_rover->pk->pubkey_algo == PUBKEY_ALGO_ECDSA)
{
int temp_hashlen = (gcry_mpi_get_nbits
(sk_rover->pk->pkey[1]));
if (sk_rover->pk->pubkey_algo == PUBKEY_ALGO_ECDSA)
{
temp_hashlen = ecdsa_qbits_from_Q (temp_hashlen);
if (!temp_hashlen)
conflict = 1; /* Better don't use the prefs. */
temp_hashlen = (temp_hashlen+7)/8;
/* Fixup for that funny nistp521 (yes, 521)
* were we need to use a 512 bit hash algo. */
if (temp_hashlen == 66)
temp_hashlen = 64;
}
else
if (sk_rover->pk->pubkey_algo == PUBKEY_ALGO_ECDSA)
{
temp_hashlen = ecdsa_qbits_from_Q (temp_hashlen);
if (!temp_hashlen)
conflict = 1; /* Better don't use the prefs. */
temp_hashlen = (temp_hashlen+7)/8;
/* Fixup for that funny nistp521 (yes, 521)
* were we need to use a 512 bit hash algo. */
if (temp_hashlen == 66)
temp_hashlen = 64;
}
else
temp_hashlen = (temp_hashlen+7)/8;
/* Pick a hash that is large enough for our
largest q or matches our Q but if tehreare
several of them we run into a conflict and
don't use the preferences. */
if (hint.digest_length < temp_hashlen)
{
if (sk_rover->pk->pubkey_algo == PUBKEY_ALGO_ECDSA)
{
if (hint.exact)
conflict = 1;
hint.exact = 1;
}
hint.digest_length = temp_hashlen;
}
}
}
if (!conflict
&& (algo = select_algo_from_prefs (pk_list,PREFTYPE_HASH,
-1,&hint)) > 0)
{
/* Note that we later check that the algo is not weak. */
recipient_digest_algo = algo;
/* Pick a hash that is large enough for our
* largest q or matches our Q but if tehreare
* several of them we run into a conflict and
* don't use the preferences. */
if (hint.digest_length < temp_hashlen)
{
if (sk_rover->pk->pubkey_algo == PUBKEY_ALGO_ECDSA)
{
if (hint.exact)
conflict = 1;
hint.exact = 1;
}
hint.digest_length = temp_hashlen;
}
}
}
}
}
for (sk_rover = sk_list; sk_rover; sk_rover = sk_rover->next)
gcry_md_enable (mfx.md, hash_for (sk_rover->pk));
if( !multifile )
iobuf_push_filter( inp, md_filter, &mfx );
if( detached && !encryptflag)
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 (!conflict
&& (algo = select_algo_from_prefs (pk_list,PREFTYPE_HASH,
-1,&hint)) > 0)
{
/* Note that we later check that the algo is not weak. */
recipient_digest_algo = algo;
}
}
}
if (opt.compress_algo && !outfile && !detached)
{
int compr_algo=opt.compress_algo;
for (sk_rover = sk_list; sk_rover; sk_rover = sk_rover->next)
gcry_md_enable (mfx.md, hash_for (sk_rover->pk));
/* 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 (!multifile)
iobuf_push_filter (inp, md_filter, &mfx);
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);
if (detached && !encryptflag)
afx->what = 2;
/* algo 0 means no compression */
if( compr_algo )
push_compress_filter(out,&zfx,compr_algo);
}
if (opt.armor && !outfile)
push_armor_filter (afx, out);
/* Write the one-pass signature packets if needed */
if (!detached) {
rc = write_onepass_sig_packets (sk_list, out,
opt.textmode && !outfile ? 0x01:0x00);
if (rc)
goto leave;
if (encryptflag)
{
efx.pk_list = pk_list;
/* fixme: set efx.cfx.datalen if known */
iobuf_push_filter( out, encrypt_filter, &efx );
}
write_status_begin_signing (mfx.md);
if (opt.compress_algo && !outfile && !detached)
{
int compr_algo = opt.compress_algo;
/* Setup the inner packet. */
if( detached ) {
if( multifile ) {
strlist_t sl;
if (!opt.explicit_compress_option
&& is_file_compressed (peekbuf, peekbuflen))
{
if (opt.verbose)
log_info(_("'%s' already compressed\n"), fname? fname: "[stdin]");
compr_algo = 0;
}
else 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);
}
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;
gpg_err_set_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 )
log_printf (" '%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_read (inp, NULL, 1<<30) != -1 )
;
iobuf_close(inp); inp = NULL;
}
if( opt.verbose )
log_printf ("\n");
}
else {
/* read, so that the filter can calculate the digest */
while (iobuf_read (inp, NULL, 1<<30) != -1 )
;
}
}
else {
rc = write_plaintext_packet (out, inp, fname,
opt.textmode && !outfile ?
(opt.mimemode? 'm':'t'):'b');
/* Algo 0 means no compression. */
if (compr_algo)
push_compress_filter (out, &zfx, compr_algo);
}
/* catch errors from above */
if (rc)
goto leave;
/* write the signatures */
rc = write_signature_packets (ctrl, sk_list, out, mfx.md,
opt.textmode && !outfile? 0x01 : 0x00,
0, duration, detached ? 'D':'S', NULL);
if( rc )
/* Write the one-pass signature packets if needed */
if (!detached)
{
rc = write_onepass_sig_packets (sk_list, out,
opt.textmode && !outfile ? 0x01:0x00);
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;
}
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;
gpg_err_set_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)
log_printf (" '%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_read (inp, NULL, 1<<30) != -1 )
;
iobuf_close(inp); inp = NULL;
}
if (opt.verbose)
log_printf ("\n");
}
else
{
/* Read, so that the filter can calculate the digest. */
while (iobuf_read (inp, NULL, 1<<30) != -1 )
;
}
}
else
{
rc = write_plaintext_packet (out, inp, fname,
opt.textmode && !outfile ?
(opt.mimemode? 'm':'t'):'b');
}
/* Catch errors from above. */
if (rc)
goto leave;
/* Write the signatures. */
rc = write_signature_packets (ctrl, sk_list, out, mfx.md,
opt.textmode && !outfile? 0x01 : 0x00,
0, duration, detached ? 'D':'S', NULL);
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;
}
/****************