To help debugging issues.
Also:
- bump sshd LogLevel to DEBUG1, for essential details.
- bump command output buffer in `run_command_varg()`
- drop redundant condition in `run_command_varg()`
- replace `BUFSIZ` with literal sizes in `run_command_varg()`.
After this patch it's showing this in the CI log for the libgcrypt
fallout that previously needed a long time to diagnose:
```
61: ---- sshd log ----
61: No matching private key for certificate: /etc/ssh/ssh_host_mldsa44-ed25519_key-cert.pub
61: Server listening on 0.0.0.0 port 22.
61: Server listening on :: port 22.
61: debug1: sshd-session version OpenSSH_10.5, OpenSSL 3.6.3 9 Jun 2026
61: Connection from 172.17.0.1 port 51878 on 172.17.0.2 port 22 rdomain ""
61: debug1: sshd-auth version OpenSSH_10.5, OpenSSL 3.6.3 9 Jun 2026 [preauth]
61: debug1: list_hostkey_types: rsa-sha2-512,rsa-sha2-256,ssh-rsa,rsa-sha2-512-cert-v01@openssh.com,
rsa-sha2-256-cert-v01@openssh.com,ssh-rsa-cert-v01@openssh.com,ecdsa-sha2-nistp256,
ecdsa-sha2-nistp256-cert-v01@openssh.com,ssh-ed25519,ssh-ed25519-cert-v01@openssh.com [preauth]
61: debug1: Local version string SSH-2.0-OpenSSH_10.5p1 Debian-1 [preauth]
61: debug1: Remote protocol version 2.0, remote software version libssh2_1.11.2_DEV [preauth]
61: debug1: compat_banner: no match: libssh2_1.11.2_DEV [preauth]
61: debug1: SSH2_MSG_KEXINIT sent [preauth]
61: debug1: SSH2_MSG_KEXINIT received [preauth]
61: debug1: kex: algorithm: (no match) [preauth]
61: Unable to negotiate with 172.17.0.1 port 51878: no matching key exchange method found.
Their offer: diffie-hellman-group-exchange-sha256,diffie-hellman-group16-sha512,
diffie-hellman-group18-sha512,diffie-hellman-group14-sha256,diffie-hellman-group14-sha1,
diffie-hellman-group1-sha1,diffie-hellman-group-exchange-sha1,ext-info-c,
kex-strict-c-v00@openssh.com [preauth]
[...]
61: ------------------
```
Follow-up to 1d0b86ac84#2484
Follow-up to 8be5716437#2174
Follow-up to 51f6259d18#1720Closes#2621
In favor of direct execution or `docker login` and `docker logout`.
Also to limit the logged-in time to the steps the require it, and to
avoid passing a secret via the command-line.
Closes#2616
To overwrite default ones with the ones matching the copied private
keys.
Fixing in sshd log:
```
Public key for /etc/ssh/ssh_host_rsa_key does not match private key
Public key for /etc/ssh/ssh_host_ecdsa_key does not match private key
Public key for /etc/ssh/ssh_host_ed25519_key does not match private key
```
Closes#2614
To enable testing on arm64 Linux and possibly also on macOS, and
possibly possibly on arm64 Windows.
Also:
- switch to debian:testing to trigger a container rebuild.
- Dockerfile: install `adduser` explicitly. Required for debian:forky.
- Dockerfile: stop installing suggested/recommended packages.
Ref: https://github.com/docker/build-push-actionCloses#2606
Implement server hostkey verification for the six ECDSA/RSA OpenSSH
certificate hostkey variants:
- `ecdsa-sha2-nistp256-cert-v01@openssh.com`
- `ecdsa-sha2-nistp384-cert-v01@openssh.com`
- `ecdsa-sha2-nistp521-cert-v01@openssh.com`
- `ssh-rsa-cert-v01@openssh.com`
- `rsa-sha2-256-cert-v01@openssh.com`
- `rsa-sha2-512-cert-v01@openssh.com`
This fixes#2434, where these algorithms were advertised and accepted as
preferences but had `NULL` hostkey `init`/`sig_verify` callbacks. A
certificate-only hostkey offer therefore caused
`LIBSSH2_ERROR_KEX_FAILURE (-5)`.
## Implementation
- ECDSA certificate parsing uses one shared init path for all three
curves. It validates the certificate type, nonce, inner curve name, and
EC point before constructing the verification context.
- RSA certificate parsing uses one shared init path for all three RSA
signature variants.
- Per-algorithm RSA `sig_verify` callbacks remain distinct.
- Per `PROTOCOL.certkeys`, the RSA/SHA-2 certificate blob itself carries
the type string `ssh-rsa-cert-v01@openssh.com`; the negotiated SHA-2
algorithm is represented by KEXINIT and the exchange signature.
- Certificate CA trust validation remains out of scope, consistent with
existing plain-hostkey handling.
## Tests
- Host CA fixtures (`keys/ca_host_ecdsa`, `keys/ca_host_rsa`) and
CA-signed host certificates for the ECDSA P-256 and RSA host keys in the
Docker OpenSSH fixture.
- The certificate algorithms are exercised through `test_read_algos.txt`
and `FIXTURE_TEST_HOSTKEY`: `ecdsa-sha2-nistp256-cert-v01@openssh.com`,
`rsa-sha2-256-cert-v01@openssh.com`,
`rsa-sha2-512-cert-v01@openssh.com`, `ssh-rsa-cert-v01@openssh.com`,
plus the pre-existing `ssh-ed25519-cert-v01@openssh.com`.
- The ECDSA P-384/P-521 certificate variants share the same codepath and
are covered by it; only P-256 is tested directly to keep the fixture
matrix lean (per maintainer review feedback).
- Disabled-backend skip entries in `tests/session_fixture.c` for the new
certificate algorithms.
- Preserved the existing ed25519 certificate test path.
Fixes#2434
Follow-up to 6036e57720#2513
Follow-up to 65a276e8fe#2064Closes#2539
- add host CA keys.
- add ed25519 signed hostkey for tests.
- make hostkey tests recognize it and skip hash checks.
- make existing tests select hostkey algos.
- add `ssh-ed25519-cert-v01@openssh.com` to the list of tested algos.
(exclude for unsupported backends.)
Ref: #2434
Inspired-by: #2435
Credits-to: Pier Carlo Cadoppi
Follow-up to 65a276e8fe#2064Closes#2513
Also: regen ed25519 key to have an empty comment like its siblings.
To be used for generating host certificate keys.
Ref: 65a276e8fe#2064
Ref: #2435Closes#2511
They are supported via the backends, except OS/400 which has its own
parser, leaving libgcrypt and WinCNG (untested) without support. With
mbedTLS PKCS8 encryption (aes-128-cbc) requires 3.6.0+.
Add RSA, ECDSA and ED25519 keys.
What I find interesting in PKCS8 private keys, is the easy way to
inspect the ASN.1 content (`openssl asn1parse -dump -in <fn>`). I could
not find similar tooling for PEM and OpenSSH files.
Also:
- tests/openssh_server/authorized_keys: sync up comments with private
keys and the generator script.
Ref: https://github.com/Mbed-TLS/mbedtls/releases/tag/v3.6.0Closes#2500
To improve coverage. This is the 'EC PRIVATE KEY` format, not tested
before. The encrypted flavor probably should not be used nowadays due to
its dependence on MD5, and thus also only tested in one job. Also use
this opportunity to introduce ECDSA 521 into the mix.
Also:
- test_auth_pubkey_ok_rsa_encrypted: require `LIBSSH2_AES_CBC`.
Closes#2499
Make it 256-bit to add variation.
Choose aes256-ctr for encryption to keep it compatible with mbedTLS,
which lacks AES-GCM support. (The other alternative, chacha-poly, has
decryption broken for keys.)
Closes#2486
Turns out this was the root cause of CI failures seen earlier, and then
worked around by reverting to older versions Docker and runner machines.
Replace/revert those workarounds by enabling the necessary legacy bits
in the test OpenSSH server configuration.
Follow-up to 8be5716437#2174
Follow-up to 51f6259d18#1720Closes#2484
Explicitly use `-t ssh-rsa` (signature algorithm) to generate
`id_rsa_signed.pub` to match the purpose of the patch it came with. Also
to differenciate this key (and test) from the subsequently merged
`id_rsa_sha2_512_signed-cert.pub`, which used the exact same keys (`-t
rsa-sha2-512`, the default) before this patch, and made these tests
duplicates.
Also:
- update `sshd_config` to actually allow using an obsolete/insecure
certificate signature `ssh-rsa`, by adding it to `CASignatureAlgorithms`.
- delete recently added entry from `HostKeyAlgorithms`, it was not
necessary.
Follow-up to 5b494b04b1#2478
Testing obsolete/insecure algs is not time best spent in CI and for
maintainers, so maybe in a next step it'd useful to disable the RSA
SHA1-based ones by default.
Ref: https://superuser.com/questions/1556852/how-to-check-if-your-ssh-keys-are-in-the-ssh-rsa2-format
Ref: 7392dc95dc#2479
Follow-up to 4b21e49d9d#710Closes#2474
I'm not sure this is required, but I think it's worth a try to untangle
RSA tests. Ref: #2474.
Also add a comment about a config name change.
Closes#2478
Also:
- switch to `id_` prefix in comments to match filenames.
- use empty comment to add variation.
- spacecheck: allow trailing spaces for `.pub` files, this is how
`ssh-keygen -C ''` generates them.
Closes#2472
- pin Debian trixie Docker image to hash.
- set Dependabot to update the pin once every month.
- set Dependabot commit message prefixes to `GHA:` (to match curl).
Closes#1724
Also:
- rename a spellcheck file to match curl.
- editorconfig: fix line width.
- editorconfig: make it use UTF-8.
- editroconfig: apply some rules to all files.
- .gitignore: drop dupe, drop `.DS_Store` (not created by this repo),
sort.
- .gitignore: add for tests executables.
Closes#1718
Also:
- add `LIBSSH2_DSA_ENABLE` to enable it explicitly.
- test the above option in CI.
- say 'deprecated' in docs and public header.
- disable DSA in the CI server config.
(OpenSSH 9.8 no longer builds with it by default)
https://www.openssh.com/txt/release-9.8
Patch-by: Jose Quaresma
- disable more DSA code when not enabled.
Fixes#1433Closes#1435
This fixes flakiness experienced recently with two OpenSSL jobs and one
libgcrypt job, and/or intermittently causing all Docker-based tests to
fail.
Reported-by: András Fekete
Fixes#1328Fixes#1329Closes#1338
```
PendingDeprecationWarning:
Copyright and licensing information for 'tests/openssh_server/Dockerfile'
has been found in both 'tests/openssh_server/Dockerfile' and in the DEP5
file located at '.reuse/dep5'. The information for these two sources has
been aggregated. In the future this behaviour will change, and you will
need to explicitly enable aggregation. [...]
```
Ref: https://github.com/libssh2/libssh2/actions/runs/6789274955/job/18456085964#step:4:4
- Dockerfile: use standard sep with `sed`
- Dockerfile: use single quotes in shell command
- appveyor.yml: use long-form option with `choco`
- tests/cmake: add language to test project
- reuse.yml: fix indentation
```
$ yamllint reuse.yml
reuse.yml
[...]
11:5 error wrong indentation: expected 6 but found 4 (indentation)
15:5 error wrong indentation: expected 6 but found 4 (indentation)
[...]
27:5 error wrong indentation: expected 6 but found 4 (indentation)
```
Cherry-picked from #1175
Also:
- uppercase `(C)`.
- add missing 'All rights reserved.' lines.
- drop duplicate 'Author' lines.
- add copyright headers where missing.
- enable copyright header check in checksrc.
Reasons for deleting years (copied as-is from curl):
- they are mostly pointless in all major jurisdictions
- many big corporations and projects already don't use them
- saves us from pointless churn
- git keeps history for us
- the year range is kept in COPYING
Closes#1082
Make sure these files get LF newlines on checkout. Before this patch
a checked out libssh2 Git repository may have used CRLF newlines in text
files, include test keys. Private keys with CRLF newlines could confuse
sshd on Windows:
```
# sshd version: 'OpenSSH_9.2, OpenSSL 1.1.1t 7 Feb 2023'
Unable to load host key "/d/a/libssh2/libssh2/tests/openssh_server/ssh_host_ed25519_key": invalid format
Unable to load host key: /d/a/libssh2/libssh2/tests/openssh_server/ssh_host_ed25519_key
```
Ref: https://github.com/libssh2/libssh2/actions/runs/4846188677/jobs/8635575847#step:6:39
Cherry-picked from #1017
- add #included C files to `EXTRA_DIST`.
Regression from 4f0f4bff5a
- fix `tests/sshd_fixture.sh` to not write into the test dir, by using
a pre-assembled `TrustedUserCAKeys` file. Update `Dockerfile` too to
use this.
Regression from a459a25302
Also update `tests/sshd_fixture.sh` to use
`openssh_server/authorized_keys` like `Dockerfile` does. And a few more
cosmetic updates.
Closes#1006
TL;DR: Sync test builds between autotools and CMake. Sync sshd
configuration between Docker and non-Docker fixtures. Bump up
sshd_config for recent OpenSSH releases.
This also opens up the path to have non-Docker tests that use a
local sshd process. Though sshd is practically unusable on Windows
CI machines out of the box, so this will need further efforts.
Details:
- cmake: run sshd fixture test just like autotool did already.
- sync tests and their order between autotools and CMake.
It makes `test_aa_warmup` the first test with both.
- cmake: load test lists from `Makefile.am`.
Needed to update the loader to throw away certain lines to keep the
converted output conform CMake syntax. Using regexp might be an
alternative way of doing this, but couldn't make it work.
- cmake: use the official way to configure test environment variables.
Switch to syntax that's extendable.
- cmake: allow to run the same test both under Docker and sshd fixture.
Useful for testing the sshd fixture runner, or how the same test
behaves in each fixture.
- update test fixture to read the username from `USER` envvar instead of
using the Dockfile-specific hardwired one, when running outside Docker.
- rework `ssh2.sh` into `sshd_fixture.sh`, to:
- allow running any tests (not just `test_ssh2`).
- configure Docker tests for running outside Docker.
- fixup `SSHD` path when running on Windows (e.g. in AppVeyor CI).
Fixes: `sshd re-exec requires execution with an absolute path`
- allow overriding `PUBKEY` and `PRIVKEY` envvars.
- allow overriding `ssh_config` via `SSHD_FIXTURE_CONFIG`.
- prepare support for running multiple tests via sshd_fixture.
Add a TAP runner for autotools and extend CMake logic. The TAP runner
loads the test list from `Makefile.am`.
Notice however that on Windows, `sshd_fixture.sh` is very flaky with
GitHub Actions. And consistently broken for subsequent tests in
AppVeyor CI:
'libssh2_session_handshake failed (-43): Failed getting banner'
Another way to try is a single sshd instance serving all tests.
For CMake this would probably mean using an external script.
- ed25519 test keys were identical for auth and host. Regenerate the
auth keypair to make them distinct.
- sync the sshd environment between Docker and sshd_fixture.
- use common via `openssh_server/sshd_config`.
- accept same auth keys.
- offer the same host keys.
- sync TrustedUserCAKeys.
- delete now unused keypairs: `etc/host*`, `etc/user*`.
- bump up startup delay for Windows (randomly, to 5 secs, from 3).
- delete `UsePrivilegeSeparation no` to avoid deprecation warnings.
`command-line line 0: Deprecated option UsePrivilegeSeparation`
- delete `Protocol 2` to avoid deprecation warnings.
It has been the default since OpenSSH 3.0 (2001-11-06).
- delete `StrictModes no` (CI tests work without it, Docker tests
never used it).
- bump `Dockerfile` base image to `testing-slim` (from `bullseye-slim`).
It needed `sshd_config` updates to keep things working with
OpenSSH 9.2 (compared to bullseye's 8.4).
- replace `ChallengeResponseAuthentication` alias with
`KbdInteractiveAuthentication`.
The former is no longer present in default `sshd_config` since
OpenSSH 8.7 (2021-08-20). This broke the `Dockerfile` script.
The new name is documented since OpenSSH 4.9 (2008-03-31)
- add `PubkeyAcceptedKeyTypes +ssh-rsa,ssh-dss,ssh-rsa-cert-v01@openssh.com`
and `HostKeyAlgorithms +ssh-rsa`.
Original-patch-by: Eric van Gyzen (@vangyzen on github)
Fixes#691
There is a new name for `PubkeyAcceptedKeyTypes`:
`PubkeyAcceptedAlgorithms`.
It requires OpenSSH 8.5 (2021-03-03) and breaks some envs so we're
not using it just yet.
- drop `rijndael-cbc@lysator.liu.se` tests and references from config.
This is a draft alias for `aes256-cbc`. No need to test it twice.
Also this alias is no longer recognized by OpenSSH 8.5 (2021-03-03).
- update `mansyntax.sh` and `sshd_fixture.sh` to not rely on `srcdir`.
Hopefully this works with out-of-tree builds.
- fix `test_read_algos.test` to honor CRLF EOLs in their inputs
(necessary when running on Windows.)
- fix `test_read_algos.test` to honor `EXEEXT`. Might be useful when
running tests under cross-builds?
- `test_ssh2.c`:
- use libssh2 API to set blocking mode. This makes it support all
platforms.
- adapt socket open timeout logic from `openssh_fixture.c`.
Sadly this did not help fix flakiness on GHA Windows.
- tests: delete unused C headers and variable initialization.
- delete unused test files: `sshd_fixture.sh.in`, `sshdwrap`,
`etc/sshd_config`.
Ref: cf80f2f4b5
- autotools: delete stray `.c` test sources from `EXTRA_DIST` in tests.
- `tests/.gitignore`: drop two stray tests.
- autotools: fix passing `SSHD` containing space (Windows needs this).
- autotools: sort `EXTRA_DIST` in tests.
- cmake: fix to add `test_ssh2` to `TEST_TARGETS`.
- fix `authorized_key` order in `tests/gen_keys.sh`.
- silence shellcheck warning in `ci/checksrc.sh`.
- set `SSHD` for autotools on GitHub Actions Windows. [skipped]
Auto-detection doesn't work (maybe because sshd is installed via
Git for Windows and we're using MSYS2's shell.)
It enables running sshd fixture (non-Docker) tests in these jobs.
I did not include this in the final patch due to flakiness:
```
Connection to 127.0.0.1:4711 attempt #0 failed: retrying...
Connection to 127.0.0.1:4711 attempt #1 failed: retrying...
Connection to 127.0.0.1:4711 attempt #2 failed: retrying...
Failure establishing SSH session: -43
```
Can be enabled with:
`export SSHD='C:/Program Files/Git/usr/bin/sshd.exe'`
Closes#996
