This is mostly mechanical change initializing all the pointers I was able to
find with some grep and manual review of sources and examples.
Used the following greps (which yield some false positives though):
git grep " \w* *\* *\w*;$"
git grep " ssh_session \w*;"
git grep " ssh_channel \w*;"
git grep " struct ssh_iterator \*\w*;"
git grep " ssh_bind \w*;"
git grep " ssh_key \w*;"
git grep " ssh_string \w*;"
git grep " ssh_buffer \w*;"
git grep " HMACCTX \w*;"
git grep " SHACTX \w*;"
grep -rinP '^(?!.*=)\s*(?:\w+\s+)*\w+\s*\*\s*\w+\s*;'
Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
ssh_match_group() has been moved from misc.c to match.c, because it fits
better with other match_*() functions in match.c
The name of the function has also been changed from "ssh_match_group" to
"match_group" to be consistent with the naming of the other match.c
functions.
Signed-off-by: Eshan Kelkar <eshankelkar@galorithm.com>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Sahana Prasad <sahana@redhat.com>
This is not completely straightforward as it requires us to do some state
shuffling.
We introduce internal flag that can turn this on in client side, so far for
testing only as we do not want to universally enable this. We also repurpose the
server flag indicating the guess was wrong also for the client to make desired
decisions.
If we found out our guess was wrong, we need to hope the server was able to
figure out this much, we need to revert the DH FSM state, drop the callbacks
from the "wrong" key exchange method and initiate the right one.
The server side is already tested by the pkd_hello_i1, which is executing tests
against dropbrear clients, which is using this flag by default out of the box.
Tested manually also with the pkd_hello --rekey to make sure the server is able
to handle the rekeying with all key exchange methods.
Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Norbert Pocs <npocs@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
Previously, the last two fields of KEXINIT were considered as always zero for
the key exchange. This was true for the sending side, but might have not been
true for the received KEXINIT from the peer.
This moves the construction of these two fields closer to their reading or
writing, instead of hardcoding them on the last possible moment before they go
as input to the hashing function.
This also allows accepting the first_kex_packet_follows on the client side, even
though there is no kex algorithm now that would allow this.
It also avoid memory leaks in case the server_set_kex() or ssh_set_client_kex()
gets called multiple times, ensuring the algorithms will not change under our
hands.
It also makes use of a new flag to track if we sent KEXINIT.
Previously, this was tracked only implicitly by the content of the
session->next_crypto->{server,client}_kex (local kex). If it was not set, we
considered it was not send. But given that we need to check the local kex even
before sending it when we receive first_kex_packet_follows flag in the KEXINIT,
this can no longer be used.
Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Norbert Pocs <npocs@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
These will be helpful when we already sent the first key exchange packet, but we
found out that our guess was wrong and we need to initiate different key
exchange method with different callbacks.
Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Norbert Pocs <npocs@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
The information if the session is client or server session is already part of
the session structure so this argument only duplicated information.
Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Norbert Pocs <npocs@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
Solving issue #110. The original work is at !231
Some changes were needed because the newly added features in master through time
Signed-off-by: Mohammad Shehar Yaar Tausif <sheharyaar48@gmail.com>
Signed-off-by: Norbert Pocs <npocs@redhat.com>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
they might be turned off and on independenty and each of them affects different
part of libssh, authentication and key exchange respectively. But only HAVE_ECC
is defined by the cmake.
Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Norbert Pocs <npocs@redhat.com>
To be able to enable sk-ecdsa, sk-edd25519 key usage from the config file
the algorithms are needed to be listed in the algorithm lists.
Signed-off-by: Norbert Pocs <npocs@redhat.com>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
The funcions can:
- add a list to the default list
- remove a list from the default list
- prepend a list to the default list
Signed-off-by: Norbert Pocs <npocs@redhat.com>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
Loglevel INFO is the default openssh configuration setting which does not print
redundant information. On a system using openssh with loglevels set by the
terms of openssh will cause unwanted log lines in the output.
recategorized based on - SSH_LOG_DEBUG are informational debug logs (no error)
Signed-off-by: Norbert Pocs <npocs@redhat.com>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
Do not print out logs when no fatal error happens.
This approach is similiar to openssh, when Error/Fatal does not print
recoverable error logs.
recategorized based on - SSH_LOG_TRACE are debug logs when error happens
Signed-off-by: Norbert Pocs <npocs@redhat.com>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
Currently Compression=no (the default) force-disables zlib algos, while
Compression=yes force-enables it. This means that mismatching options between
client and server lead to connection failure. This can easily happen if the
server has default settings but the client specifies Compression=yes.
OpenSSH treats the option as a "prefer compression" setting:
Compression=no -> none,zlib@openssh.com,zlib (default)
Compression=yes -> zlib@openssh.com,zlib,none
This commit changes the libssh behaviour to the same as OpenSSH.
Signed-off-by: Fabian Vogt <fabian@ritter-vogt.de>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
Normally, the length of session_id and secret_hash is the same,
but if we will get into rekeying with a peer that changes preference
of key exchange algorithm, the new secret hash can be larger or
smaller than the previous session_id causing invalid reads or writes.
Resolves https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=35485
Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
OpenSSL 1.0.1 has support for CTR & GCM modes so the checks here are no
longer needed. This allows for a bunch of additional cleanup of the old
code.
As for old MacOS versions etc, LibreSSL is a kind of compatibility layer
there but things already don't work anyway with that, so it doesn't
break anything that isn't already broken. OpenSSL is needed on MacOS
separately anyway (like installed with Homebrew).
Signed-off-by: Dirkjan Bussink <d.bussink@gmail.com>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
OpenSSL 0.9.7 is already not supported, so clean up the old legacy bits
for that as well.
Signed-off-by: Dirkjan Bussink <d.bussink@gmail.com>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
There's currently a bug in libssh that a handshake doesn't complete if
there is no overlap between HMAC methods, but when an AEAD cipher is
used.
In case of an AEAD cipher such as chacha20-poly1305 or aes256-gcm, the
HMAC algorithm that is being picked is not relevant. But the problem
here is that the HMAC still needs to have an overlap in the handshake,
even if it is not used afterwards.
This was found with a very strict server side configuration with libssh
where only AEAD ciphers and EtM HMAC modes are accepted. The client
tested against was dropbear.
Dropbear does have support for chacha20-poly1305 and AES GCM modes, but
no support for EtM HMAC modes. This meant that the libssh server in this
case rejected the dropbear client, even though it is perfectly able to
serve it since dropbear supports AEAD algorithms.
The fix implemented here updates the HMAC phase of the handshake to
handle this case. If it detects an AEAD cipher is used, it uses the HMAC
abbreviations for the method instead. This is the same name that is used
in other places as well. It matches the client to server and server to
client values, but it does depend on the order of things in the
ssh_kex_types_e enum, which I'm assuming here is ok since it's explicit.
I've looked at how to add a test for this, but I couldn't really find a
suitable place for it. I would love some tips if this is easily
possible, or if it's easier for someone else to contribute, that's of
course welcome too.
Signed-off-by: Dirkjan Bussink <d.bussink@gmail.com>
Reviewed-by: Anderson Toshiyuki Sasaki <ansasaki@redhat.com>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
OpenSSH disabled them in 2014 and 2017 for servers and clients so its our
turn to follow the suit.
Fixes T236
Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
Previously, there was non-consistent usage of constans SSH_KEX_METHODS,
KEX_METHODS_SIZE and of magic number 10 to reference the arrays used
for algorithm negotiation by peers. This commit settles down to the single
constant and its usage throughout the whole codebase.
Fixes T195
Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
Replace all occurrences of the deprecated function ssh_print_hexa() with
the introduced ssh_log_hexdump().
Signed-off-by: Anderson Toshiyuki Sasaki <ansasaki@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
Previously, if the SSH_OPTIONS_HOSTKEYS option was set by any mean,
including the client configuration file, the keys in known_hosts files
wouldn't be considered before advertising the list of wanted host keys.
This could result in the client requesting the server to provide a
signature using a key not present in the known_hosts files (e.g. when
the first wanted algorithm in SSH_OPTIONS_HOSTKEYS is not present in the
known_hosts files), causing a host key mismatch and possible key
rejection.
Now, the keys present in the known_hosts files are prioritized over the
other wanted keys. This do not change the fact that only keys of types
present in the list set in SSH_OPTIONS_HOSTKEYS will be accepted and
prioritized following the order defined by such list.
The new wanted list of hostkeys is given by:
- The keys present in known_hosts files, ordered by preference defined
in SSH_OPTIONS_HOSTKEYS. If the option is not set, a default order
of preference is used.
- The other keys present in the same option are appended without adding
duplicates. If the option is not set, the default list of keys is
used.
Fixes: T156
Signed-off-by: Anderson Toshiyuki Sasaki <ansasaki@redhat.com>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
Previously, if the client supported rsa-sha2-256 or rsa-sha2-512, the
server would advertise the extensions as supported without checking its
own list of allowed algorithms. Now the server will only advertise
allowed signature algorithms.
Signed-off-by: Anderson Toshiyuki Sasaki <ansasaki@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
