Fix bug in mpi_tdiv_q_2exp.

* mpi/mpi-internal.h (MPN_COPY_INCR): Make it work.
--

This bug has been with us since the version 0.0.0 of GnuPG.
Fortunately it only affects an optimized code path which is rarely
used in practice: If the shift size matches the size of a
limb (i.e.. 32 or 64); this is is_prime in primegen.c.  Over there the
Rabin-Miller test may fail with a probability of 2^-31 (that is if the
to be tested prime - 1 has the low 32 bits cleared).  In practice the
probability is even much less because we first do a Fermat test on the
randomly generated candidates which sorts out the majority of
composite numbers.

The bug in MPN_COPY_INCR was found by Sven Bjorn.

Signed-off-by: Werner Koch <wk@gnupg.org>

(back ported from Libgcrypt
 commit 7f7a5ef59962ae1a819b5060f9b781469bfe27d5)
gpg: Fix bug with deeply nested compressed packets.

* g10/mainproc.c (MAX_NESTING_DEPTH): New.
(proc_compressed): Return an error code.
(check_nesting): New.
(do_proc_packets): Check packet nesting depth.  Handle errors from
check_compressed.

Signed-off-by: Werner Koch <wk@gnupg.org>
gpg: Limit the nesting level of I/O filters.

* until/iobuf.c (MAX_NESTING_FILTER): New.
(iobuf_push_filter2): Limit the nesting level.
--

This is a more general fix for the nested compression packet bug.  In
particular this helps g10/import.c:read_block to stop pushing
compression filters onto an iobuf stream.

Signed-off-by: Werner Koch <wk@gnupg.org>
keyserver: Allow use of cURL's default CA store.

* keyserver/gpgkeys_curl.c (main): Set CURLOPT_CAINFO only if a file
has been given.
* keyserver/gpgkeys_hkp.c (main): Ditto.
--

GnuPG-bug-id: 1542
Signed-off-by: Werner Koch <wk@gnupg.org>
(cherry picked from commit e957b9b3f408491f36660499b215aebcf2633a95)
gpg: Distinguish between missing and cleared key flags.

* include/cipher.h (PUBKEY_USAGE_NONE): New.
* g10/getkey.c (parse_key_usage): Set new flag.
--

We do not want to use the default capabilities (derived from the
algorithm) if any key flags are given in a signature.  Thus if key
flags are used in any way, the default key capabilities are never
used.

This allows to create a key with key flags set to all zero so it can't
be used.  This better reflects common sense.
(cherry picked from commit 4bde12206c5bf199dc6e12a74af8da4558ba41bf)
(cherry picked from commit 0a805ed1604ef3e9b27f3e22a936a2d439300e9f)

Resolved conflicts:
	include/cipher.h
gpg: Allow setting of all zero key flags

* g10/keygen.c (do_add_key_flags): Do not check for empty key flags.
(cherry picked from commit b693ec02c467696bf9d7324dd081e279f9965151)
(cherry picked from commit dd868acb0d13a9f119c0536777350a6c237a66a1)
gpg: Protect against rogue keyservers sending secret keys.

* g10/options.h (IMPORT_NO_SECKEY): New.
* g10/keyserver.c (keyserver_spawn, keyserver_import_cert): Set new
flag.
* g10/import.c (import_secret_one): Deny import if flag is set.
--

By modifying a keyserver or a DNS record to send a secret key, an
attacker could trick a user into signing using a different key and
user id.  The trust model should protect against such rogue keys but
we better make sure that secret keys are never received from remote
sources.

Suggested-by: Stefan Tomanek
Signed-off-by: Werner Koch <wk@gnupg.org>
(cherry picked from commit e7abed3448c1c1a4e756c12f95b665b517d22ebe)

Resolved conflicts:
	g10/options.h
gpg: Print a "not found" message for an unknown key in --key-edit.

* g10/keyedit.c (keyedit_menu): Print message.
--

GnuPG-bug-id: 1420
Signed-off-by: Werner Koch <wk@gnupg.org>
(cherry picked from commit 0bf54e60d31389812d05c3fd29bece876204561d)
doc: Update from master.
po: Autoupdate due to changed order of strings.

--
Release 1.4.15
Post release updates.

--
gpg: Do not require a trustdb with --always-trust.

* g10/tdbio.c (tdbio_set_dbname): Add arg R_NOFILE.
* g10/trustdb.c (trustdb_args): Add field no_trustdb.
(init_trustdb): Set that field.
(revalidation_mark):  Take care of a nonexistent trustdb file.
(read_trust_options): Ditto.
(get_ownertrust): Ditto.
(get_min_ownertrust): Ditto.
(update_ownertrust): Ditto.
(update_min_ownertrust): Ditto.
(clear_ownertrusts): Ditto.
(cache_disabled_value): Ditto.
(check_trustdb_stale): Ditto.
(get_validity): Ditto.
* g10/gpg.c (main): Do not create a trustdb with most commands for
trust-model always.
--

This slightly changes the semantics of most commands in that they
won't create a trustdb if --trust-model=always is used.  It just does
not make sense to create a trustdb if there is no need for it.

Signed-off-by: Werner Koch <wk@gnupg.org>
(cherry picked from commit 1a0eeaacd1bf09fe5125dbc3f56016bc20f3512e)

Resolved conflicts:
	g10/gpg.c
	g10/tdbio.h
	g10/trustdb.c
 (indentation fixes)
mpi: Fix syntax error for mips64 and gcc < 4.4

* mpi/longlong.h [__mips && gcc < 4.4]: Fix cpp syntax error.
--

GnuPG-bug-id: 1465
Print the keyid for key packets with --list-packets.

* g10/parse-packet.c (parse_key): Add keyid printing.
--

This is backport from GnuPG-2.  Note that the --list-packets command
is for debugging only and not part iof the stable API.

Signed-off-by: Werner Koch <wk@gnupg.org>
mpi: mpi-pow improvements

* mpi/mpi-pow.c (USE_ALGORITHM_SIMPLE_EXPONENTIATION): New.
(mul_mod) [!USE_ALGORITHM_SIMPLE_EXPONENTIATION]: New.
(mpi_powm) [!USE_ALGORITHM_SIMPLE_EXPONENTIATION]: New implementation
of left-to-right k-ary exponentiation.
--

This is a backport from Libgcrypt commit
45aa6131e93fac89d46733b3436d960f35fb99b2

    Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>

    For the Yarom/Falkner flush+reload cache side-channel attack, we
    changed the code so that it always calls the multiplication
    routine (even if we can skip it to get result).  This results some
    performance regression.

    This change is for recovering performance with efficient
    algorithm.

Signed-off-by: Werner Koch <wk@gnupg.org>