/* Pack an s2k iteration count into the form specified in 2440. If
we're in between valid values, round up. With value 0 return the
old default. */
unsigned char
encode_s2k_iterations (int iterations)
{
gpg_error_t err;
unsigned char c=0;
unsigned char result;
unsigned int count;
if (!iterations)
{
unsigned long mycnt;
/* Ask the gpg-agent for a useful iteration count. */
err = agent_get_s2k_count (&mycnt);
if (err || mycnt < 65536)
{
/* Don't print an error if an older agent is used. */
if (err && gpg_err_code (err) != GPG_ERR_ASS_PARAMETER)
log_error (_("problem with the agent: %s\n"), gpg_strerror (err));
/* Default to 65536 which we used up to 2.0.13. */
return 96;
}
else if (mycnt >= 65011712)
return 255; /* Largest possible value. */
else
return encode_s2k_iterations ((int)mycnt);
}
if (iterations <= 1024)
return 0; /* Command line arg compatibility. */
if (iterations >= 65011712)
return 255;
/* Need count to be in the range 16-31 */
for (count=iterations>>6; count>=32; count>>=1)
c++;
result = (c<<4)|(count-16);
if (S2K_DECODE_COUNT(result) < iterations)
result++;
return result;
}
/* Hash a passphrase using the supplied s2k.
Always needs: dek->algo, s2k->mode, s2k->hash_algo. */
static void
hash_passphrase ( DEK *dek, char *pw, STRING2KEY *s2k)
{
gcry_md_hd_t md;
int pass, i;
int used = 0;
int pwlen = strlen(pw);
assert ( s2k->hash_algo );
dek->keylen = openpgp_cipher_get_algo_keylen (dek->algo);
if ( !(dek->keylen > 0 && dek->keylen <= DIM(dek->key)) )
BUG();
if (gcry_md_open (&md, s2k->hash_algo, 1))
BUG ();
for (pass=0; used < dek->keylen ; pass++ )
{
if ( pass )
{
gcry_md_reset (md);
for (i=0; i < pass; i++ ) /* Preset the hash context. */
gcry_md_putc (md, 0 );
}
if ( s2k->mode == 1 || s2k->mode == 3 )
{
int len2 = pwlen + 8;
ulong count = len2;
if ( s2k->mode == 3 )
{
count = S2K_DECODE_COUNT(s2k->count);
if ( count < len2 )
count = len2;
}
/* Fixme: To avoid DoS attacks by sending an sym-encrypted
packet with a very high S2K count, we should either cap
the iteration count or CPU seconds based timeout. */
/* A little bit complicated because we need a ulong for count. */
while ( count > len2 ) /* maybe iterated+salted */
{
gcry_md_write ( md, s2k->salt, 8 );
gcry_md_write ( md, pw, pwlen );
count -= len2;
}
if ( count < 8 )
gcry_md_write ( md, s2k->salt, count );
else
{
gcry_md_write ( md, s2k->salt, 8 );
count -= 8;
gcry_md_write ( md, pw, count );
}
}
else
gcry_md_write ( md, pw, pwlen );
gcry_md_final( md );
i = gcry_md_get_algo_dlen ( s2k->hash_algo );
if ( i > dek->keylen - used )
i = dek->keylen - used;
memcpy (dek->key+used, gcry_md_read (md, s2k->hash_algo), i);
used += i;
}
gcry_md_close(md);
}
/* Return a new DEK object using the string-to-key specifier S2K. Use
KEYID and PUBKEY_ALGO to prompt the user. Returns NULL is the user
selected to cancel the passphrase entry and if CANCELED is not
NULL, sets it to true.
MODE 0: Allow cached passphrase
1: Ignore cached passphrase
2: Ditto, but create a new key
3: Allow cached passphrase; use the S2K salt as the cache ID
4: Ditto, but create a new key
*/
DEK *
passphrase_to_dek_ext (u32 *keyid, int pubkey_algo,
int cipher_algo, STRING2KEY *s2k, int mode,
const char *tryagain_text,
const char *custdesc, const char *custprompt,
int *canceled)
{
char *pw = NULL;
DEK *dek;
STRING2KEY help_s2k;
int dummy_canceled;
char s2k_cacheidbuf[1+16+1], *s2k_cacheid = NULL;
if (!canceled)
canceled = &dummy_canceled;
*canceled = 0;
if ( !s2k )
{
log_assert (mode != 3 && mode != 4);
/* This is used for the old rfc1991 mode
* Note: This must match the code in encode.c with opt.rfc1991 set */
s2k = &help_s2k;
s2k->mode = 0;
s2k->hash_algo = S2K_DIGEST_ALGO;
}
/* Create a new salt or what else to be filled into the s2k for a
new key. */
if ((mode == 2 || mode == 4) && (s2k->mode == 1 || s2k->mode == 3))
{
gcry_randomize (s2k->salt, 8, GCRY_STRONG_RANDOM);
if ( s2k->mode == 3 )
{
/* We delay the encoding until it is really needed. This is
if we are going to dynamically calibrate it, we need to
call out to gpg-agent and that should not be done during
option processing in main(). */
if (!opt.s2k_count)
opt.s2k_count = encode_s2k_iterations (0);
s2k->count = opt.s2k_count;
}
}
/* If we do not have a passphrase available in NEXT_PW and status
information are request, we print them now. */
if ( !next_pw && is_status_enabled() )
{
char buf[50];
if ( keyid )
{
emit_status_need_passphrase (keyid,
keyid[2] && keyid[3]? keyid+2:NULL,
pubkey_algo);
}
else
{
snprintf (buf, sizeof buf -1, "%d %d %d",
cipher_algo, s2k->mode, s2k->hash_algo );
write_status_text ( STATUS_NEED_PASSPHRASE_SYM, buf );
}
}
/* If we do have a keyID, we do not have a passphrase available in
NEXT_PW, we are not running in batch mode and we do not want to
ignore the passphrase cache (mode!=1), print a prompt with
information on that key. */
if ( keyid && !opt.batch && !next_pw && mode!=1 )
{
PKT_public_key *pk = xmalloc_clear( sizeof *pk );
char *p;
p = get_user_id_native(keyid);
tty_printf ("\n");
tty_printf (_("You need a passphrase to unlock the secret key for\n"
"user: \"%s\"\n"),p);
xfree(p);
if ( !get_pubkey( pk, keyid ) )
{
const char *s = openpgp_pk_algo_name ( pk->pubkey_algo );
tty_printf (_("%u-bit %s key, ID %s, created %s"),
nbits_from_pk( pk ), s?s:"?", keystr(keyid),
strtimestamp(pk->timestamp) );
if ( keyid[2] && keyid[3]
&& keyid[0] != keyid[2] && keyid[1] != keyid[3] )
{
if ( keystrlen () > 10 )
{
tty_printf ("\n");
tty_printf (_(" (subkey on main key ID %s)"),
keystr(&keyid[2]) );
}
else
tty_printf ( _(" (main key ID %s)"), keystr(&keyid[2]) );
}
tty_printf("\n");
}
tty_printf("\n");
free_public_key (pk);
}
if ( next_pw )
{
/* Simply return the passphrase we already have in NEXT_PW. */
pw = next_pw;
next_pw = NULL;
}
else if ( have_static_passphrase () )
{
/* Return the passphrase we have stored in FD_PASSWD. */
pw = xmalloc_secure ( strlen(fd_passwd)+1 );
strcpy ( pw, fd_passwd );
}
else
{
if ((mode == 3 || mode == 4) && (s2k->mode == 1 || s2k->mode == 3))
{
memset (s2k_cacheidbuf, 0, sizeof s2k_cacheidbuf);
*s2k_cacheidbuf = 'S';
bin2hex (s2k->salt, 8, s2k_cacheidbuf + 1);
s2k_cacheid = s2k_cacheidbuf;
}
if (opt.pinentry_mode == PINENTRY_MODE_LOOPBACK)
{
char buf[32];
snprintf (buf, sizeof (buf), "%u", 100);
write_status_text (STATUS_INQUIRE_MAXLEN, buf);
}
/* Divert to the gpg-agent. */
pw = passphrase_get (keyid, mode == 2, s2k_cacheid,
(mode == 2 || mode == 4)? opt.passphrase_repeat : 0,
tryagain_text, custdesc, custprompt, canceled);
if (*canceled)
{
xfree (pw);
write_status( STATUS_MISSING_PASSPHRASE );
return NULL;
}
}
if ( !pw || !*pw )
write_status( STATUS_MISSING_PASSPHRASE );
/* Hash the passphrase and store it in a newly allocated DEK object.
Keep a copy of the passphrase in LAST_PW for use by
get_last_passphrase(). */
dek = xmalloc_secure_clear ( sizeof *dek );
dek->algo = cipher_algo;
if ( (!pw || !*pw) && (mode == 2 || mode == 4))
dek->keylen = 0;
else
{
gpg_error_t err;
dek->keylen = openpgp_cipher_get_algo_keylen (dek->algo);
if (!(dek->keylen > 0 && dek->keylen <= DIM(dek->key)))
BUG ();
err = gcry_kdf_derive (pw, strlen (pw),
s2k->mode == 3? GCRY_KDF_ITERSALTED_S2K :
s2k->mode == 1? GCRY_KDF_SALTED_S2K :
/* */ GCRY_KDF_SIMPLE_S2K,
s2k->hash_algo, s2k->salt, 8,
S2K_DECODE_COUNT(s2k->count),
dek->keylen, dek->key);
if (err)
{
log_error ("gcry_kdf_derive failed: %s", gpg_strerror (err));
xfree (pw);
xfree (dek);
write_status( STATUS_MISSING_PASSPHRASE );
return NULL;
}
}
if (s2k_cacheid)
memcpy (dek->s2k_cacheid, s2k_cacheid, sizeof dek->s2k_cacheid);
xfree(last_pw);
last_pw = pw;
return dek;
}
/* Return a new DEK object using the string-to-key specifier S2K.
* Returns NULL if the user canceled the passphrase entry and if
* CANCELED is not NULL, sets it to true.
*
* If CREATE is true a new passphrase sll be created. If NOCACHE is
* true the symmetric key caching will not be used. */
DEK *
passphrase_to_dek (int cipher_algo, STRING2KEY *s2k,
int create, int nocache,
const char *tryagain_text, int *canceled)
{
char *pw = NULL;
DEK *dek;
STRING2KEY help_s2k;
int dummy_canceled;
char s2k_cacheidbuf[1+16+1];
char *s2k_cacheid = NULL;
if (!canceled)
canceled = &dummy_canceled;
*canceled = 0;
if ( !s2k )
{
log_assert (create && !nocache);
/* This is used for the old rfc1991 mode
* Note: This must match the code in encode.c with opt.rfc1991 set */
memset (&help_s2k, 0, sizeof (help_s2k));
s2k = &help_s2k;
s2k->hash_algo = S2K_DIGEST_ALGO;
}
/* Create a new salt or what else to be filled into the s2k for a
new key. */
if (create && (s2k->mode == 1 || s2k->mode == 3))
{
gcry_randomize (s2k->salt, 8, GCRY_STRONG_RANDOM);
if ( s2k->mode == 3 )
{
/* We delay the encoding until it is really needed. This is
if we are going to dynamically calibrate it, we need to
call out to gpg-agent and that should not be done during
option processing in main(). */
if (!opt.s2k_count)
opt.s2k_count = encode_s2k_iterations (0);
s2k->count = opt.s2k_count;
}
}
/* If we do not have a passphrase available in NEXT_PW and status
information are request, we print them now. */
if ( !next_pw && is_status_enabled() )
{
char buf[50];
snprintf (buf, sizeof buf, "%d %d %d",
cipher_algo, s2k->mode, s2k->hash_algo );
write_status_text ( STATUS_NEED_PASSPHRASE_SYM, buf );
}
if ( next_pw )
{
/* Simply return the passphrase we already have in NEXT_PW. */
pw = next_pw;
next_pw = NULL;
}
else if ( have_static_passphrase () )
{
/* Return the passphrase we have stored in FD_PASSWD. */
pw = xmalloc_secure ( strlen(fd_passwd)+1 );
strcpy ( pw, fd_passwd );
}
else
{
if (!nocache && (s2k->mode == 1 || s2k->mode == 3))
{
memset (s2k_cacheidbuf, 0, sizeof s2k_cacheidbuf);
*s2k_cacheidbuf = 'S';
bin2hex (s2k->salt, 8, s2k_cacheidbuf + 1);
s2k_cacheid = s2k_cacheidbuf;
}
if (opt.pinentry_mode == PINENTRY_MODE_LOOPBACK)
{
char buf[32];
snprintf (buf, sizeof (buf), "%u", 100);
write_status_text (STATUS_INQUIRE_MAXLEN, buf);
}
/* Divert to the gpg-agent. */
pw = passphrase_get (create && nocache, s2k_cacheid,
create? opt.passphrase_repeat : 0,
tryagain_text, canceled);
if (*canceled)
{
xfree (pw);
write_status( STATUS_MISSING_PASSPHRASE );
return NULL;
}
}
if ( !pw || !*pw )
write_status( STATUS_MISSING_PASSPHRASE );
/* Hash the passphrase and store it in a newly allocated DEK object.
Keep a copy of the passphrase in LAST_PW for use by
get_last_passphrase(). */
dek = xmalloc_secure_clear ( sizeof *dek );
dek->algo = cipher_algo;
if ( (!pw || !*pw) && create)
dek->keylen = 0;
else
{
gpg_error_t err;
dek->keylen = openpgp_cipher_get_algo_keylen (dek->algo);
if (!(dek->keylen > 0 && dek->keylen <= DIM(dek->key)))
BUG ();
err = gcry_kdf_derive (pw, strlen (pw),
s2k->mode == 3? GCRY_KDF_ITERSALTED_S2K :
s2k->mode == 1? GCRY_KDF_SALTED_S2K :
/* */ GCRY_KDF_SIMPLE_S2K,
s2k->hash_algo, s2k->salt, 8,
S2K_DECODE_COUNT(s2k->count),
dek->keylen, dek->key);
if (err)
{
log_error ("gcry_kdf_derive failed: %s", gpg_strerror (err));
xfree (pw);
xfree (dek);
write_status( STATUS_MISSING_PASSPHRASE );
return NULL;
}
}
if (s2k_cacheid)
memcpy (dek->s2k_cacheid, s2k_cacheid, sizeof dek->s2k_cacheid);
xfree(last_pw);
last_pw = pw;
return dek;
}