string: Correctly burn the string buffer.

Signed-off-by: Andreas Schneider <asn@cryptomilk.org>
Reviewed-by: Aris Adamantiadis <aris@0xbadc0de.be>
(cherry picked from commit 1ddb99c46ffbeeac52f27a630b50670848b39e0c)
wrapper: fix z_stream leak

Ensure to free the z_stream structures as allocated from
the gzip.c initcompress, initdecompress functions.

Signed-off-by: Jon Simons <jon@jonsimons.org>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
(cherry picked from commit 092fe0b727399cd971709c16c030bc093ca54d87)
crypto: check malloc return in ssh_mac_ctx_init

Signed-off-by: Jon Simons <jon@jonsimons.org>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
(cherry picked from commit af25c5e668fa817521496ac2278127b516f219d3)
pki_gcrypt: Initialize 'type_c' in 'pki_do_sign_sessionid'

Add missing initialization of 'type_c' field of a SSH signature in
'pki_do_sign_sessionid' procedure.

If libssh is compiled with GCrypt, 'dh_handshake_server' fails with
"Could not sign the session id" error.  The change fixes that.

Signed-off-by: Artyom V. Poptsov <poptsov.artyom@gmail.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
(cherry picked from commit aaae6cd97d3b99061fcf5444d491895690fb4cde)