Remove support for pre-authentication compression. Doing
compression early in the protocol probably seemed reasonable in the 1990s,
but today it's clearly a bad idea in terms of both cryptography (cf. multiple
compression oracle attacks in TLS) and attack surface.
Moreover, to support it across privilege-separation zlib needed
the assistance of a complex shared-memory manager that made the
required attack surface considerably larger.
Prompted by Guido Vranken pointing out a compiler-elided security
check in the shared memory manager found by Stack
(http://css.csail.mit.edu/stack/); ok deraadt@ markus@
NB. pre-auth authentication has been disabled by default in sshd
for >10 years.
Upstream-ID: 32af9771788d45a0779693b41d06ec199d849caf
support plain curve25519-sha256 KEX algorithm now that it
is approaching standardisation (same algorithm is currently supported as
curve25519-sha256@libssh.org)
Upstream-ID: 5e2b6db2e72667048cf426da43c0ee3fc777baa2
remove 3des-cbc from the client's default proposal;
64-bit block ciphers are not safe in 2016 and we don't want to wait until
attacks like sweet32 are extended to SSH.
As 3des-cbc was the only mandatory cipher in the SSH RFCs, this may
cause problems connecting to older devices using the defaults, but
it's highly likely that such devices already need explicit
configuration for KEX and hostkeys anyway.
ok deraadt, markus, dtucker
Upstream-ID: a505dfe65c6733af0f751b64cbc4bb7e0761bc2f
add support for additional fixed DH groups from
draft-ietf-curdle-ssh-kex-sha2-03
diffie-hellman-group14-sha256 (2K group)
diffie-hellman-group16-sha512 (4K group)
diffie-hellman-group18-sha512 (8K group)
based on patch from Mark D. Baushke and Darren Tucker
ok markus@
Upstream-ID: ac00406ada4f0dfec41585ca0839f039545bc46f
turn off more old crypto in the client: hmac-md5, ripemd,
truncated HMACs, RC4, blowfish. ok markus@ dtucker@
Upstream-ID: 96aa11c2c082be45267a690c12f1d2aae6acd46e
implement SHA2-{256,512} for RSASSA-PKCS1-v1_5 signatures
(user and host auth) based on draft-rsa-dsa-sha2-256-03.txt and
draft-ssh-ext-info-04.txt; with & ok djm@
Upstream-ID: cf82ce532b2733e5c4b34bb7b7c94835632db309
Turn off DSA by default; add HostKeyAlgorithms to the
server and PubkeyAcceptedKeyTypes to the client side, so it still can be
tested or turned back on; feedback and ok djm@
Upstream-ID: 8450a9e6d83f80c9bfed864ff061dfc9323cec21
turn off 1024 bit diffie-hellman-group1-sha1 key
exchange method (already off in server, this turns it off in the client by
default too) ok dtucker@
Upstream-ID: f59b88f449210ab7acf7d9d88f20f1daee97a4fa
Reorder client proposal to prefer
diffie-hellman-group-exchange-sha1 over diffie-hellman-group14-sha1. ok djm@
Upstream-ID: 552c08d47347c3ee1a9a57d88441ab50abe17058
[mac.c myproposal.h umac.c]
UMAC can use our local fallback implementation of AES when OpenSSL isn't
available. Glue code straight from Ted Krovetz's original umac.c.
ok markus@
repeatedly):
- markus@cvs.openbsd.org 2014/03/25 09:40:03
[myproposal.h]
trimm default proposals.
This commit removes the weaker pre-SHA2 hashes, the broken ciphers
(arcfour), and the broken modes (CBC) from the default configuration
(the patch only changes the default, all the modes are still available
for the config files).
ok djm@, reminded by tedu@ & naddy@ and discussed with many
- deraadt@cvs.openbsd.org 2014/03/26 17:16:26
[myproposal.h]
The current sharing of myproposal[] between both client and server code
makes the previous diff highly unpallatable. We want to go in that
direction for the server, but not for the client. Sigh.
Brought up by naddy.
- markus@cvs.openbsd.org 2014/03/27 23:01:27
[myproposal.h ssh-keyscan.c sshconnect2.c sshd.c]
disable weak proposals in sshd, but keep them in ssh; ok djm@
[Makefile.in PROTOCOL PROTOCOL.chacha20poly1305 authfile.c chacha.c]
[chacha.h cipher-chachapoly.c cipher-chachapoly.h cipher.c cipher.h]
[dh.c myproposal.h packet.c poly1305.c poly1305.h servconf.c ssh.1]
[ssh.c ssh_config.5 sshd_config.5] Add a new protocol 2 transport
cipher "chacha20-poly1305@openssh.com" that combines Daniel
Bernstein's ChaCha20 stream cipher and Poly1305 MAC to build an
authenticated encryption mode.
Inspired by and similar to Adam Langley's proposal for TLS:
http://tools.ietf.org/html/draft-agl-tls-chacha20poly1305-03
but differs in layout used for the MAC calculation and the use of a
second ChaCha20 instance to separately encrypt packet lengths.
Details are in the PROTOCOL.chacha20poly1305 file.
Feedback markus@, naddy@; manpage bits Loganden Velvindron @ AfriNIC
ok markus@ naddy@
NID_X9_62_prime256v1, NID_secp384r1 and NID_secp521r1 and test that the
latter actually works before using it. Fedora (at least) has NID_secp521r1
that doesn't work (see https://bugzilla.redhat.com/show_bug.cgi?id=1021897).
[kex.c kex.h myproposal.h ssh-keyscan.c sshconnect2.c sshd.c]
use curve25519 for default key exchange (curve25519-sha256@libssh.org);
initial patch from Aris Adamantiadis; ok djm@
[PROTOCOL authfile.c cipher.c cipher.h kex.c kex.h monitor_wrap.c]
[myproposal.h packet.c ssh_config.5 sshd_config.5]
support AES-GCM as defined in RFC 5647 (but with simpler KEX handling)
ok and feedback djm@
[PROTOCOL authfile.c cipher.c cipher.h kex.h mac.c myproposal.h]
[packet.c ssh_config.5 sshd_config.5]
add encrypt-then-mac (EtM) modes to openssh by defining new mac algorithms
that change the packet format and compute the MAC over the encrypted
message (including the packet size) instead of the plaintext data;
these EtM modes are considered more secure and used by default.
feedback and ok djm@
[mac.c myproposal.h ssh_config.5 sshd_config.5]
Remove hmac-sha2-256-96 and hmac-sha2-512-96 MACs since they were removed
from draft6 of the spec and will not be in the RFC when published. Patch
from mdb at juniper net via bz#2023, ok markus.
[kexecdhc.c kexecdhs.c key.c key.h myproposal.h packet.c readconf.c]
[ssh-agent.c ssh-ecdsa.c ssh-keygen.c ssh.c] Disable ECDH and ECDSA on
platforms that don't have the requisite OpenSSL support. ok dtucker@
[PROTOCOL PROTOCOL.agent PROTOCOL.certkeys auth2-jpake.c authfd.c]
[authfile.c buffer.h dns.c kex.c kex.h key.c key.h monitor.c]
[monitor_wrap.c myproposal.h packet.c packet.h pathnames.h readconf.c]
[ssh-add.1 ssh-add.c ssh-agent.1 ssh-agent.c ssh-keygen.1 ssh-keygen.c]
[ssh-keyscan.1 ssh-keyscan.c ssh-keysign.8 ssh.1 ssh.c ssh2.h]
[ssh_config.5 sshconnect.c sshconnect2.c sshd.8 sshd.c sshd_config.5]
[uuencode.c uuencode.h bufec.c kexecdh.c kexecdhc.c kexecdhs.c ssh-ecdsa.c]
Implement Elliptic Curve Cryptography modes for key exchange (ECDH) and
host/user keys (ECDSA) as specified by RFC5656. ECDH and ECDSA offer
better performance than plain DH and DSA at the same equivalent symmetric
key length, as well as much shorter keys.
Only the mandatory sections of RFC5656 are implemented, specifically the
three REQUIRED curves nistp256, nistp384 and nistp521 and only ECDH and
ECDSA. Point compression (optional in RFC5656 is NOT implemented).
Certificate host and user keys using the new ECDSA key types are supported.
Note that this code has not been tested for interoperability and may be
subject to change.
feedback and ok markus@
[PROTOCOL.certkeys auth-options.c auth-options.h auth-rsa.c]
[auth2-pubkey.c authfd.c key.c key.h myproposal.h ssh-add.c]
[ssh-agent.c ssh-dss.c ssh-keygen.1 ssh-keygen.c ssh-rsa.c]
[sshconnect.c sshconnect2.c sshd.c]
revised certificate format ssh-{dss,rsa}-cert-v01@openssh.com with the
following changes:
move the nonce field to the beginning of the certificate where it can
better protect against chosen-prefix attacks on the signature hash
Rename "constraints" field to "critical options"
Add a new non-critical "extensions" field
Add a serial number
The older format is still support for authentication and cert generation
(use "ssh-keygen -t v00 -s ca_key ..." to generate a v00 certificate)
ok markus@
- djm@cvs.openbsd.org 2010/02/26 20:29:54
[PROTOCOL PROTOCOL.agent PROTOCOL.certkeys addrmatch.c auth-options.c]
[auth-options.h auth.h auth2-pubkey.c authfd.c dns.c dns.h hostfile.c]
[hostfile.h kex.h kexdhs.c kexgexs.c key.c key.h match.h monitor.c]
[myproposal.h servconf.c servconf.h ssh-add.c ssh-agent.c ssh-dss.c]
[ssh-keygen.1 ssh-keygen.c ssh-rsa.c ssh.1 ssh.c ssh2.h sshconnect.c]
[sshconnect2.c sshd.8 sshd.c sshd_config.5]
Add support for certificate key types for users and hosts.
OpenSSH certificate key types are not X.509 certificates, but a much
simpler format that encodes a public key, identity information and
some validity constraints and signs it with a CA key. CA keys are
regular SSH keys. This certificate style avoids the attack surface
of X.509 certificates and is very easy to deploy.
Certified host keys allow automatic acceptance of new host keys
when a CA certificate is marked as sh/known_hosts.
see VERIFYING HOST KEYS in ssh(1) for details.
Certified user keys allow authentication of users when the signing
CA key is marked as trusted in authorized_keys. See "AUTHORIZED_KEYS
FILE FORMAT" in sshd(8) for details.
Certificates are minted using ssh-keygen(1), documentation is in
the "CERTIFICATES" section of that manpage.
Documentation on the format of certificates is in the file
PROTOCOL.certkeys
feedback and ok markus@
[kex.h mac.c mac.h monitor_wrap.c myproposal.h packet.c ssh.1]
[ssh_config.5 sshd.8 sshd_config.5]
Add a new MAC algorithm for data integrity, UMAC-64 (not default yet,
must specify umac-64@openssh.com). Provides about 20% end-to-end speedup
compared to hmac-md5. Represents a different approach to message
authentication to that of HMAC that may be beneficial if HMAC based on
one of its underlying hash algorithms is found to be vulnerable to a
new attack. http://www.ietf.org/rfc/rfc4418.txt
in conjunction with and OK djm@
[kex.c kex.h monitor.c myproposal.h ssh-keyscan.c sshconnect2.c sshd.c]
Implement the diffie-hellman-group-exchange-sha256 key exchange method
using the SHA256 code in libc (and wrapper to make it into an OpenSSL
EVP), interop tested against CVS PuTTY
NB. no portability bits committed yet
[kex.c kex.h myproposal.h packet.c packet.h servconf.c session.c]
[sshconnect2.c sshd.c sshd_config sshd_config.5]
add a new compression method that delays compression until the user
has been authenticated successfully and set compression to 'delayed'
for sshd.
this breaks older openssh clients (< 3.5) if they insist on
compression, so you have to re-enable compression in sshd_config.
ok djm@
djm@openbsd.org
markus@openbsd.org
Damien Miller
dtucker@openbsd.org
jsg@openbsd.org
Darren Tucker
Tim Rice