void
write_status_text (int no, const char *text)
{
write_status_strings (no, text, NULL);
}
/****************
* Decrypt the data, specified by ED with the key DEK.
*/
int
decrypt_data (ctrl_t ctrl, void *procctx, PKT_encrypted *ed, DEK *dek)
{
decode_filter_ctx_t dfx;
byte *p;
int rc=0, c, i;
byte temp[32];
unsigned blocksize;
unsigned nprefix;
dfx = xtrycalloc (1, sizeof *dfx);
if (!dfx)
return gpg_error_from_syserror ();
dfx->refcount = 1;
if ( opt.verbose && !dek->algo_info_printed )
{
if (!openpgp_cipher_test_algo (dek->algo))
log_info (_("%s encrypted data\n"),
openpgp_cipher_algo_name (dek->algo));
else
log_info (_("encrypted with unknown algorithm %d\n"), dek->algo );
dek->algo_info_printed = 1;
}
{
char buf[20];
snprintf (buf, sizeof buf, "%d %d", ed->mdc_method, dek->algo);
write_status_text (STATUS_DECRYPTION_INFO, buf);
}
if (opt.show_session_key)
{
char numbuf[25];
char *hexbuf;
snprintf (numbuf, sizeof numbuf, "%d:", dek->algo);
hexbuf = bin2hex (dek->key, dek->keylen, NULL);
if (!hexbuf)
{
rc = gpg_error_from_syserror ();
goto leave;
}
log_info ("session key: '%s%s'\n", numbuf, hexbuf);
write_status_strings (STATUS_SESSION_KEY, numbuf, hexbuf, NULL);
xfree (hexbuf);
}
rc = openpgp_cipher_test_algo (dek->algo);
if (rc)
goto leave;
blocksize = openpgp_cipher_get_algo_blklen (dek->algo);
if ( !blocksize || blocksize > 16 )
log_fatal ("unsupported blocksize %u\n", blocksize );
nprefix = blocksize;
if ( ed->len && ed->len < (nprefix+2) )
{
/* An invalid message. We can't check that during parsing
because we may not know the used cipher then. */
rc = gpg_error (GPG_ERR_INV_PACKET);
goto leave;
}
if ( ed->mdc_method )
{
if (gcry_md_open (&dfx->mdc_hash, ed->mdc_method, 0 ))
BUG ();
if ( DBG_HASHING )
gcry_md_debug (dfx->mdc_hash, "checkmdc");
}
rc = openpgp_cipher_open (&dfx->cipher_hd, dek->algo,
GCRY_CIPHER_MODE_CFB,
(GCRY_CIPHER_SECURE
| ((ed->mdc_method || dek->algo >= 100)?
0 : GCRY_CIPHER_ENABLE_SYNC)));
if (rc)
{
/* We should never get an error here cause we already checked
* that the algorithm is available. */
BUG();
}
/* log_hexdump( "thekey", dek->key, dek->keylen );*/
rc = gcry_cipher_setkey (dfx->cipher_hd, dek->key, dek->keylen);
if ( gpg_err_code (rc) == GPG_ERR_WEAK_KEY )
{
log_info(_("WARNING: message was encrypted with"
" a weak key in the symmetric cipher.\n"));
rc=0;
}
else if( rc )
{
log_error("key setup failed: %s\n", gpg_strerror (rc) );
goto leave;
}
if (!ed->buf)
{
log_error(_("problem handling encrypted packet\n"));
goto leave;
}
gcry_cipher_setiv (dfx->cipher_hd, NULL, 0);
if ( ed->len )
{
for (i=0; i < (nprefix+2) && ed->len; i++, ed->len-- )
{
if ( (c=iobuf_get(ed->buf)) == -1 )
break;
else
temp[i] = c;
}
}
else
{
for (i=0; i < (nprefix+2); i++ )
if ( (c=iobuf_get(ed->buf)) == -1 )
break;
else
temp[i] = c;
}
gcry_cipher_decrypt (dfx->cipher_hd, temp, nprefix+2, NULL, 0);
gcry_cipher_sync (dfx->cipher_hd);
p = temp;
/* log_hexdump( "prefix", temp, nprefix+2 ); */
if (dek->symmetric
&& (p[nprefix-2] != p[nprefix] || p[nprefix-1] != p[nprefix+1]) )
{
rc = gpg_error (GPG_ERR_BAD_KEY);
goto leave;
}
if ( dfx->mdc_hash )
gcry_md_write (dfx->mdc_hash, temp, nprefix+2);
dfx->refcount++;
dfx->partial = ed->is_partial;
dfx->length = ed->len;
if ( ed->mdc_method )
iobuf_push_filter ( ed->buf, mdc_decode_filter, dfx );
else
iobuf_push_filter ( ed->buf, decode_filter, dfx );
if (opt.unwrap_encryption)
{
char *filename;
estream_t fp;
rc = get_output_file ("", 0, ed->buf, &filename, &fp);
if (! rc)
{
iobuf_t output = iobuf_esopen (fp, "w", 0);
armor_filter_context_t *afx = NULL;
if (opt.armor)
{
afx = new_armor_context ();
push_armor_filter (afx, output);
}
iobuf_copy (output, ed->buf);
if ((rc = iobuf_error (ed->buf)))
log_error (_("error reading '%s': %s\n"),
filename, gpg_strerror (rc));
else if ((rc = iobuf_error (output)))
log_error (_("error writing '%s': %s\n"),
filename, gpg_strerror (rc));
iobuf_close (output);
if (afx)
release_armor_context (afx);
}
}
else
proc_packets (ctrl, procctx, ed->buf );
ed->buf = NULL;
if (dfx->eof_seen > 1 )
rc = gpg_error (GPG_ERR_INV_PACKET);
else if ( ed->mdc_method )
{
/* We used to let parse-packet.c handle the MDC packet but this
turned out to be a problem with compressed packets: With old
style packets there is no length information available and
the decompressor uses an implicit end. However we can't know
this implicit end beforehand (:-) and thus may feed the
decompressor with more bytes than actually needed. It would
be possible to unread the extra bytes but due to our weird
iobuf system any unread is non reliable due to filters
already popped off. The easy and sane solution is to care
about the MDC packet only here and never pass it to the
packet parser. Fortunatley the OpenPGP spec requires a
strict format for the MDC packet so that we know that 22
bytes are appended. */
int datalen = gcry_md_get_algo_dlen (ed->mdc_method);
log_assert (dfx->cipher_hd);
log_assert (dfx->mdc_hash);
gcry_cipher_decrypt (dfx->cipher_hd, dfx->defer, 22, NULL, 0);
gcry_md_write (dfx->mdc_hash, dfx->defer, 2);
gcry_md_final (dfx->mdc_hash);
if ( dfx->defer[0] != '\xd3'
|| dfx->defer[1] != '\x14'
|| datalen != 20
|| memcmp (gcry_md_read (dfx->mdc_hash, 0), dfx->defer+2, datalen))
rc = gpg_error (GPG_ERR_BAD_SIGNATURE);
/* log_printhex("MDC message:", dfx->defer, 22); */
/* log_printhex("MDC calc:", gcry_md_read (dfx->mdc_hash,0), datalen); */
}
leave:
release_dfx_context (dfx);
return rc;
}
/*
* 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 (_("cipher algorithm '%s' may not be used 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_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_aead = use_aead (pk_list, cfx.dek->algo);
if (!cfx.dek->use_aead)
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 or AEAD. 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 || cfx.dek->use_aead)
&& 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 (cfx.dek->key, cfx.dek->keylen, "DEK is: ");
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, cfx.dek->use_aead,
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,
cfx.dek->use_aead? cipher_filter_aead
/**/ : cipher_filter_cfb,
&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 || cfx.dek->use_aead))
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;
}
