Commit Graph

156 Commits

Author SHA1 Message Date
Pavol Žáčik
9b4ee9c6d4 gssapi: enable gssapi-keyex in FIPS mode
All gssapi-keyex tests have to be disabled in Centos Stream 8
because the KEX is not allowed in FIPS. In Centos Stream 9,
only tests against OpenSSH have to be disabled because
OpenSSH only enables gssapi-keyex since Centos Stream 10.

Signed-off-by: Pavol Žáčik <pzacik@redhat.com>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
2026-01-05 12:24:13 +01:00
Gauravsingh Sisodia
a0707afc3e reformat: gssapi key exchange
Signed-off-by: Gauravsingh Sisodia <xaerru@gmail.com>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
2026-01-05 12:24:13 +01:00
Gauravsingh Sisodia
c1aab9903f feat: add null hostkey for server
fix: skip gssapi tests in fips mode

fix: skip gssapi_key_exchange_null test on ubuntu and tumbleweed

fix: return early when rc != 0 to show error

tests: replace int asserts by ssh return code asserts

fix: add fatal error when hostkeys are not found and gssapi kex is not enabled

ci: add comment linking gssapi null kex bug in ubuntu and tumbleweed

fix: don't specify hostkeys in config instead of deleting files

tests: assert kex method was null

refactor: remove redundant include

refactor: better error message

fix: check null before accessing in gssapi.c

fix: allow setting no hostkeys
Signed-off-by: Gauravsingh Sisodia <xaerru@gmail.com>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
2026-01-05 12:24:13 +01:00
Gauravsingh Sisodia
9044fcdb52 feat: add "gssapi-keyex" for server
feat: add negative auth client tests, and more key exchange server tests

feat: add function for checkinf if GSSAPI key exchange was performed
Signed-off-by: Gauravsingh Sisodia <xaerru@gmail.com>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
2026-01-05 12:24:13 +01:00
Gauravsingh Sisodia
bc5211d055 feat: add gssapi key exchange
feat: add generic functions for importing name and initializing ctx

feat: add suffix to gsskex algs dynamically

feat: move gssapi key exchange to another file

feat: add gssapi key exchange for server

refactor: remove unnecessary fields in gssapi struct

refactor: add some documentation and improve logging

fix: remove gss_dh callbacks

feat: add a check to see if GSSAPI is configured correctly

fix: memory leaks

feat: add client side "gssapi-keyex" auth

feat: add gssapi_key_exchange_algs for server

fix: some memory issues

feat: add gssapi kex options to config

feat: add check to see if GSSAPI key exchange was performed

feat: add more tests for gssapi key exchange

fix: add valgrind supp

Signed-off-by: Gauravsingh Sisodia <xaerru@gmail.com>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
2026-01-05 12:24:00 +01:00
Nikhil V
4feb0dd79d Improve doxygen documentation
Signed-off-by: Nikhil V <nikhilgreyshines@gmail.com>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
2025-12-18 13:44:05 +01:00
nikhil-nari
f8d943afda Improve doxygen docs
Signed-off-by: Nikhil V <nikhilgreyshines@gmail.com>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
2025-12-18 13:44:05 +01:00
Jakub Jelen
ee180c660e server: Check strdup allocation failure
Thanks Xiaoke Wang for the report!

Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Pavol Žáčik <pzacik@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
2025-12-12 18:06:45 +01:00
Nguyễn Thái Ngọc Duy
168302b9d6 Fix ssh_handle_key_exchange() timeout
See libssh-mirror#311 for background. But in some case, it's possible to
trigger the code in ssh_handle_key_exchange() to move session state
directly to SSH_SESSION_STATE_AUTHENTICATED. The exit condition for this
function is SSH_SESSION_STATE_AUTHENTICATING though, so when it happens,
ssh_handle_key_exchange() will time out eventually.

The fix is straightforward. Tested with the problematic
client (trilead-ssh2) and made sure the bad condition happened (and not
cause timeout)

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
2025-07-24 13:08:46 +02:00
Jakub Jelen
2eb2af4426 CVE-2025-4878 Initialize pointers where possible
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>
2025-06-23 15:24:30 +02:00
Abdallah Alhadad
aa681c268e extensions: Host-bound public key authentication
Signed-off-by: Abdallah Alhadad <abdallahselhdad@gmail.com>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
2025-03-18 17:34:04 +02:00
Jakub Jelen
b7018c17c7 Fix implicit type conversions and warnings on windows builds
The visual studio windows builds spit dozens of lines of warnings
on these.

Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
2025-01-03 15:18:53 +01:00
Aris Adamantiadis
3876976ced CVE-2023-48795: Server side mitigations
Signed-off-by: Aris Adamantiadis <aris@0xbadc0de.be>
Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
2023-12-18 17:35:04 +01:00
Jakub Jelen
8dbe055328 CVE-2023-1667:kex: Correctly handle last fields of KEXINIT also in the client side
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>
2023-05-04 11:51:17 +02:00
Jakub Jelen
1c85acb6e6 CVE-2023-1667:kex: Remove needless function argument
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>
2023-05-04 11:51:17 +02:00
Jakub Jelen
c00a3369c2 server: Reformat ssh_server_connection_callback
Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Norbert Pocs <npocs@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
2023-05-04 11:51:17 +02:00
Jakub Jelen
e1be63d78d server: Reformat callback_receive_banner
Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Norbert Pocs <npocs@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
2023-05-04 11:51:17 +02:00
Jakub Jelen
b0ce6935fc server: Reformat ssh_handle_key_exchange
Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Norbert Pocs <npocs@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
2023-05-04 11:51:17 +02:00
Mohammad Shehar Yaar Tausif
a3a13eb3a8 Remove support for DSA Keys
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>
2023-02-02 14:49:06 +01:00
Norbert Pocs
9931f158e0 server: Add documentation to some functions
Signed-off-by: Norbert Pocs <npocs@redhat.com>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
2023-02-01 15:26:02 +01:00
Norbert Pocs
b7c1f792cc documentation: Fix Missing param doxygen warnings
Signed-off-by: Norbert Pocs <npocs@redhat.com>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
2023-02-01 15:26:02 +01:00
Norbert Pocs
01e9341d10 options.c: Add support for openssh config +,-,^
These features allow for options Ciphers, HostKeyAlgorithms, KexAlgorithms and
MACs to append, remove and prepend to the default list of algorithms
respectively

Signed-off-by: Norbert Pocs <npocs@redhat.com>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
2022-11-18 20:28:32 +01:00
Seung Min Park
2074fb1948 Fix ssh_send_issue_banner() for CMD(PowerShell)
Signed-off-by: Seung Min Park <smpark@pnpsecure.com>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
2022-10-31 15:09:55 +01:00
Xiang Xiao
787735098f change the format specifier of uint32_t from PRId32 to PRIu32
Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
2022-10-12 11:50:46 +02:00
Xiang Xiao
b53d0608b6 fix printf format warning
uint32_t should be formated by PRI?32

Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
Change-Id: I811cfd764010f9e8bb599b370155ac065ee1905c
2022-10-12 11:50:45 +02:00
Norbert Pocs
657d9143d1 SSH_LOG_DEBUG: Recategorize loglevels
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>
2022-10-07 09:13:19 +02:00
Norbert Pocs
4070784029 server.c: Add missing function documentation
Signed-off-by: Norbert Pocs <npocs@redhat.com>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
2022-10-04 10:35:02 +02:00
renmingshuai
0799775185 session->socket_callbacks.data will be set to ssh_packet_socket_callback
in ssh_packet_register_socket_callback. Here is redundant.

Signed-off-by: renmingshuai <renmingshuai@huawei.com>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
2022-08-25 14:51:53 +02:00
Seung Min Park
4978f30320 Add ssh_send_issue_banner() API
Signed-off-by: Seung Min Park <smpark@pnpsecure.com>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
2022-07-02 07:04:48 +02:00
Andreas Schneider
7bcc2d83a4 packet: Fix ssh_packet_socket_callback() return value
According to the documentation the return value is the number of
processed bytes, so the returned value is never negative. We should not
use ssize_t in public headers as it isn't available on Windows! We only
have it defined in priv.h!

Signed-off-by: Andreas Schneider <asn@cryptomilk.org>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
2022-06-22 12:28:30 +02:00
Norbert Pocs
442599f0d1 Fix type mismatch warnings
Signed-off-by: Norbert Pocs <npocs@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
2022-06-15 14:47:06 +02:00
brian m. carlson
c573adced4 server: reply with PK_OK with correct algorithm
RFC 4252 §7 states that the public key algorithm in a
SSH_MSG_USERAUTH_PK_OK response is the public key algorithm name from
the request.  When using RSA with SHA-2, this will be either
"rsa-sha2-256" or "rsa-sha2-512" as specified by RFC 8332 §3.2.

However, currently libssh emits the public key type instead, which is
"ssh-rsa".  This is not in conformance with the RFCs, so let's fix this
by storing the signature type and emitting it in our response instead of
the public key when sending SSH_MSG_USERAUTH_PK_OK in the server.

Signed-off-by: brian m. carlson <bk2204@github.com>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
2021-12-07 12:27:18 +01:00
Andreas Schneider
321b27b788 server: Use SSH_STRING_FREE()
Fixes T183

Signed-off-by: Andreas Schneider <asn@cryptomilk.org>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
2019-12-09 16:08:03 +01:00
Andreas Schneider
9ae81c5ceb SSH-01-006: Add missing NULL check in server_set_kex()
Fixes T193

Signed-off-by: Andreas Schneider <asn@cryptomilk.org>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
2019-12-09 16:08:03 +01:00
Andreas Schneider
6cef3e10bf server: Cast auth_methods to uint32_t
Fixes T188

Signed-off-by: Andreas Schneider <asn@cryptomilk.org>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
2019-12-09 16:08:03 +01:00
Andreas Schneider
442d22da60 server: Make sure methods is a valid value before casting
Fixes T188

Signed-off-by: Andreas Schneider <asn@cryptomilk.org>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
2019-12-09 16:08:03 +01:00
Jakub Jelen
c8a621c606 Use only one variable denoting the size of methods arrays
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>
2019-11-18 11:59:01 +01:00
Jakub Jelen
1ebf506913 server: Use really the negotiated signature type
Generally, when the extension negotiation is enabled and client supports
SHA2 algorithms for RSA, they are supposed to be prioritized against the
old SHA1. If it is not (ssh-rsa is listed in front of rsa-sha2-* hostkey
algorithms during negotiation), the server wrongly tries to provide the
new typo of signature, ignoring the negotiated algirithm

This commit propagates the digest algorithm from negotiation to the actual
signature functions, which were previously responsible for decision
about the hash algorithm based just on the negotiated extensions.

Fixes T191

Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
2019-11-07 15:55:32 +01:00
David Wedderwille
32eec7b418 SSH_LOG: Adjust log level from SSH_LOG_WARNING to SSH_LOG_PROTOCOL
Fixes T149

Signed-off-by: David Wedderwille <davidwe@posteo.de>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
2019-06-13 16:43:44 +02:00
Anderson Toshiyuki Sasaki
1b7146e28f server: Send only allowed algorithms in extension
Send only allowed algorithms in server-sig-algs extension if in FIPS
mode.

Signed-off-by: Anderson Toshiyuki Sasaki <ansasaki@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
2019-06-13 14:37:39 +02:00
Anderson Toshiyuki Sasaki
54d76098ed kex, pki, server, options: Filter algorithms in FIPS mode
When in FIPS mode, filter the algorithms to enable only the allowed
ones.  If any algorithm is explicitly set through options or
configuration file, they are kept.

Signed-off-by: Anderson Toshiyuki Sasaki <ansasaki@redhat.com>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
2019-06-12 11:13:52 +02:00
Anderson Toshiyuki Sasaki
dc35bbbeb1 server: Use default methods instead of all
Previously, when no methods were set, the server would enable all
supported methods.  This changes this behaviour by setting only the
default methods.

The server in pkd_daemon.c was changed to set explicitly all the
supported methods to keep the previous behaviour.

Signed-off-by: Anderson Toshiyuki Sasaki <ansasaki@redhat.com>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
2019-06-12 10:17:54 +02:00
Anderson Toshiyuki Sasaki
250a0be0f9 options: Added an option to set server HostKey algorithms
The added option SSH_BIND_OPTIONS_HOSTKEY_ALGORITHMS allows restricting
the signature algorithms to offer to the client for host authentication.
The list set is used as a filter of allowed algorithms.

First a list of possible signature algorithms to offer is created from
the keys set and then such list is filtered against the allowed
algorithms.

Signed-off-by: Anderson Toshiyuki Sasaki <ansasaki@redhat.com>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
2019-06-12 10:17:54 +02:00
Anderson Toshiyuki Sasaki
f4363f5655 options: Add option to set server accepted pubkey types
The added option SSH_BIND_OPTIONS_PUBKEY_ACCEPTED_KEY_TYPES allows
restricting the allowed public key types accepted by the server for
authentication.

Signed-off-by: Anderson Toshiyuki Sasaki <ansasaki@redhat.com>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
2019-06-12 10:17:54 +02:00
Jon Simons
19cb6f1b6c server: fix sending SSH_MSG_EXT_INFO upon rekey
Fix libssh server sending SSH_MSG_EXT_INFO messages upon rekey: clients
do not expect that message during rekey, and OpenSSH in particular will
log error messages along the lines of:

    "kex protocol error: type 7 seq 15"

when the message is received during a rekey.

To fix, check against the session connected flag, which only transitions
to non-zero following the first successful authentication.

bf2c7128ab adds logic to resolve this
issue, but it turns out that checking the session_state to avoid
sending the message is insufficient, because that state is re-set
to SSH_SESSION_STATE_KEXINIT_RECEIVED during rekey.

The before-and-after effects of this change can be observed using the
pkd --rekey flag as so:

    ./pkd_hello -t torture_pkd_openssh_rsa_rsa_sha2_256 \
      -i1 --rekey=16 -v -v -v 2>&1 |
      grep -e 'KEY' -e 'EXT'

^ where before the change, multiple SSH_MSG_EXT_INFO send messages are
logged; after, there is only a single SSH_MSG_EXT_INFO logged once upon
the first initial key exchange.

Cross-reference: https://bugs.libssh.org/T121.

Signed-off-by: Jon Simons <jon@jonsimons.org>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
2019-04-29 14:00:39 +02:00
Jon Simons
c0f3a96089 server: fix queued USERAUTH_SUCCESS rekey bug
Fix a bug with server-side rekeying where the session state at hand
has been toggled to SSH_SESSION_STATE_AUTHENTICATED before performing
the packet send of the SSH2_MSG_USERAUTH_SUCCESS message.

Before this change, what can happen is that during the packet send,
the SSH2_MSG_USERAUTH_SUCCESS message can end up being queued due
to a small rekey data limit value.  libssh server will then proceed
to attempt to send KEX-related rekeying messages to the client before
the client has received USERAUTH_SUCCESS.  OpenSSH clients do not
expect to undergo rekeying before having been authenticated, and so
will exit with error when this happens.

The behavior before and after can be observed with the pkd test making
use of its new --rekey flag:

    ./pkd_hello -t torture_pkd_openssh_rsa_rsa_default -i1 --rekey=16 -v -v -v

A new CMake test entry is added for the above variation and can be run
with:

    ARGS="-R pkd_hello_rekey" make test

Before the fix, the test will fail; after, the test succeeds while
performing rekeying once every 16 bytes.

Signed-off-by: Jon Simons <jon@jonsimons.org>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
2019-04-29 14:00:39 +02:00
Ben Toews
b1f3cfec34 libssh: deprecate SSH_KEYTYPE_ECDSA
This type is imprecise. We often need the ecdsa_nid in addition to the key type
in order to do anything. We replace this singluar ECDSA type with one type per
curve.

Signed-off-by: Ben Toews <mastahyeti@gmail.com>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
2019-04-17 10:21:42 +02:00
David Wedderwille
b73ffb3f91 connector: Fallback on the socket output callback
Fixes T124

Signed-off-by: David Wedderwille <davidwe@posteo.de>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
2019-02-21 14:03:20 +01:00
Aris Adamantiadis
53c88375fe dh-gex: Add server implementation
Signed-off-by: Aris Adamantiadis <aris@0xbadc0de.be>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
2019-01-24 13:06:33 +01:00
Aris Adamantiadis
e42a423a24 kex: use runtime callbacks (server)
Signed-off-by: Aris Adamantiadis <aris@0xbadc0de.be>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
2019-01-24 09:19:59 +01:00