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Support FilC glob_t without gl_flags - #17

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codex/filc-glob-portability-20260913
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@qoega

@qoega qoega commented Sep 13, 2026

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🫧 FilC's libc provides glob_t without the non-standard gl_flags member. ClickHouse's pre-generated libssh configuration enables glob support and reports that member as available, so both client and server configuration parsing failed to compile.

Use aggregate zero initialization under __FILC__. This preserves Include glob expansion without depending on the libc-specific field.

Validated by compiling ClickHouse's _nuraft target with FilC and ENABLE_LIBRARIES=ON; both libssh translation units pass and the 112,930,994-byte NuRaft archive links successfully.

Jakuje and others added 30 commits August 12, 2025 12:13
Since 07cb0be we are not closing the user provided FDs,
but the above change also resulted in memory leak during
ssh_disconnect that left the poll_handle allocated during
reset.

Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
…essed wrongly

Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
…ent's wrong KEX guess

Signed-off-by: Francesco Rollo <eferollo@gmail.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
Signed-off-by: Andreas Schneider <asn@cryptomilk.org>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
As it may a cause a use after free if `send` fails when
ssh_poll_ctx_dopoll does its callback
ssh_poll_ctx_dopoll still wants to use the poll object later

Signed-off-by: Philippe Antoine <p.antoine@catenacyber.fr>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
Signed-off-by: Praneeth Sarode <praneethsarode@gmail.com>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
…dized

The specification is now in the last call, data point is allocated so there is
no need to stick to the namespaces alias anymore

https://datatracker.ietf.org/doc/draft-ietf-sshm-ntruprime-ssh/

Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Sahana Prasad <sahana@redhat.com>
Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Sahana Prasad <sahana@redhat.com>
Signed-off-by: Francesco Rollo <eferollo@gmail.com>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
Signed-off-by: Philippe Antoine <p.antoine@catenacyber.fr>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
Signed-off-by: Praneeth Sarode <praneethsarode@gmail.com>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
Signed-off-by: Praneeth Sarode <praneethsarode@gmail.com>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
Define a new constant for the default RSA key size for consistency.

Signed-off-by: Praneeth Sarode <praneethsarode@gmail.com>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
Signed-off-by: Praneeth Sarode <praneethsarode@gmail.com>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
… function

The logic for creating the buffer to be verified from an sk signature from ssh_pki_signature_verify has been separated into a new function named pki_prepare_sk_signature_buffer to allow for convenient reuse of this logic.

Signed-off-by: Praneeth Sarode <praneethsarode@gmail.com>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
The libssh requires mbedTLS to have support for threading. Given the
way how the mbedTLS builds are configured (at least to my limited
understanding), by modifying mbedtls_config.h header file, this
changes the silent failure to a message on stderr pointing the
user in the right direction.

Fixes: #304

Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
Originally reported by Jeremy Cross <jcross@beyondtrust.com> in #461

Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
Jakuje and others added 27 commits February 5, 2026 15:43
Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Pavol Žáčik <pzacik@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
Signed-off-by: Eshan Kelkar <eshankelkar@galorithm.com>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
Addresses issue #319

The commit description explains:
1. Fix for sftp aio + read
2. Fix for sftp aio + write

1. Fix for sftp aio + read
-------------------------
The reproducer provided in the issue description had a model
as follows (with one jump host):
fd_1---(socket_pair)---fd_2---(connector)----channel(fd_3)-----server

Via debugging, it was noticed that the channel connected directly to
the server stored a lot of unbuffered data (received from the server)
that wasn't being written to fd_2 via the connector API.

(Here on, channel refers to the channel(fd_3) in the diagram connected
directly to the server)

Consider the situation, where after a bit of progress in the transfer,
the server has sent all the requested data (requested via outstanding
requests) and all of that data is stored in channel->stdout_buffer. Say
this data is 10,000 bytes.

At this point, all the client (fd_1) is doing is waiting for all
outstanding requests. (and processing thei responses)

- POLLOUT event callback gets generated indicating that fd_2 is
  available for writing.

- ssh_connector_fd_out_cb() gets called to handle the POLLOUT.

- Assuming connector->in_available was true, 4096 (CHUNKSIZE) bytes
  get read from the channel. (really channel->stdout_buffer) leaving
  10,000 - 4096 = 5904 bytes unread in the channel.

- The read bytes are sent via fd_2 (so that fd_1 can recv them)

- After this, the callback sets connector->in_available to 0 and
  connector->out_wontblock to 0.

- Since out_wontblock has been set to 0 ssh_connector_reset_pollevents()
  (called after the callback returns) will consider POLLOUT events on the
  connector output.

- (Based on assumption before) Since the client (fd_1) is eagerly
  awaiting responses and processing them, the received data gets
  processed quickly and fd_2 is available for sending/writing.

- POLLOUT event gets generated for fd_2 indicating that its available
  for writing/sending to fd_1

- ssh_connector_fd_out_cb() gets called to handle the POLLOUT

- Since connector->in_available is 0 (and
  ssh_connector_channel_data_cb() has not been trigerred in between
  as we have assumed before that all the data has already been received on the
  channel and is stored in the channel->stdout_buffer), ssh_connector_fd_out_cb()
  does nothing besides setting connector->out_wontblock to 1.

- Since out_wontblock has been set to 1 ssh_connector_reset_pollevents()
  (called after the callback returns) will IGNORE POLLOUT events on the
  connector output.

- So, at this point, the channel->buffer contains 5706 bytes and the
  fd_2 is available for writing/sending (out_wontblock is 1), but
  nothing happens and the transfer gets stalled/hanged.

In my opinion, this hanging occurs because connector->in_available was
incorrectly set to 0 despite the channel buffer having 5706 bytes in it.

This commit changes that code to consider the data available to read
on the channel (includes buffered data as well as polled data on
channel's internal fd) and taking that into consideration to set
in_available appropriately. (Instead of unconditionally setting it to 0 as the
current code does) so that the next time POLLOUT gets received on fd_2
the ssh_connector_fd_out_cb() does read from the channel and write to
fd_2 (as the connector->in_available flag would be set).

2. Fix for sftp aio + write
-------------------------------------
On writing tests for sftp aio + proxyjump, it was encountered
that file uploads were also hanging. Though I was not able to
pin point the exact cause for this hanging, the nature of hanging
was observed to be as follows:

- sftp aio write + proxyjump blocks/hangs occasionally (not always)

- It hangs at different points in the test

- hang point 1: Sometimes it hangs after sending the first write request
  (i.e. the second write request call hangs and never returns, at this point
  we are not even waiting for response, just sending data). A lot of pending
  data to write to socket/fd was noticed at this hang point.

- hang point 2: Sometimes it hangs while waiting for the second write request
  response.

- It hangs at ssh_handle_packets_termination (i.e. this is the
  call that never returns), in context to hang point 1, this occurs due to
  trying to flush the channel during sftp_packet_write, and in context to
  hang point 2, this occurs due to trying to read an sftp response packet.

- Not sure why, but more the verbose logging/printing I do, the lesser
  occasionally test hangs (e.g. 1 test in 6-7 test runs), maybe this could
  be a hint for a race condition / thread interaction related bug, but am
  not sure.

Fix: On modifying the connector code to mark out_wontblock
to 0 in case of output channel only when the channel's
remote window is 0, the hanging no longer occured.

Though, as mentioned before, I don't know the exact problem
(i.e. case causing hanging) the fix addresses, but the fix
is logical (if remote window is +ve data can still be written
to channel and hence out_wontblock should not be reset to 0, it should
be set to 1) and fixes the issue hence is added to this commit.

Signed-off-by: Eshan Kelkar <eshankelkar@galorithm.com>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Pavol Žáčik <pzacik@redhat.com>
Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Pavol Žáčik <pzacik@redhat.com>
Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Pavol Žáčik <pzacik@redhat.com>
This affects libgcrypt and mbedTLS backends. The OpenSSL backend is
using OpenSSL implementation of the Ed25519 which is compared correctly.

Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Pavol Žáčik <pzacik@redhat.com>
Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Pavol Žáčik <pzacik@redhat.com>
Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
The specially crafted patterns (from configuration files) could cause
exhaustive search or timeouts.

Previous attempts to fix this by limiting recursion to depth 16 avoided
stack overflow, but not timeouts. This is due to the backtracking,
which caused the exponential time complexity O(N^16) of existing algorithm.

This is code comes from the same function from OpenSSH, where this code
originates from, which is not having this issue (due to not limiting the number
of recursion), but will also easily exhaust stack due to unbound recursion:

openssh/openssh-portable@05bcd0c

This is an attempt to simplify the algorithm by preventing the backtracking
to previous wildcard, which should keep the same behavior for existing inputs
while reducing the complexity to linear O(N*M).

This fixes the long-term issue we had with fuzzing as well as recently reported
security issue by Kang Yang.

Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Pavol Žáčik <pzacik@redhat.com>
Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Pavol Žáčik <pzacik@redhat.com>
Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Pavol Žáčik <pzacik@redhat.com>
Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Pavol Žáčik <pzacik@redhat.com>
…e configuration files

Changes also the reading of known_hosts to use the new helper function

Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
Signed-off-by: Andreas Schneider <asn@cryptomilk.org>
Signed-off-by: Andreas Schneider <asn@cryptomilk.org>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
thanks oss-fuzz

https://issues.oss-fuzz.com/u/1/issues/482613826
Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Pavol Žáčik <pzacik@redhat.com>
Reviewed-by: Sahana Prasad <sahana@redhat.com>
Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Pavol Žáčik <pzacik@redhat.com>
Reviewed-by: Sahana Prasad <sahana@redhat.com>
Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Pavol Žáčik <pzacik@redhat.com>
Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Pavol Žáčik <pzacik@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
…ent-option

Expose the configured `IdentityAgent` and `IdentitiesOnly` options
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Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you all sign our Contributor License Agreement before we can accept your contribution.
2 out of 5 committers have signed the CLA.

✅ alexey-milovidov
✅ qoega
❌ cryptomilk
❌ Jakuje
❌ galorithm
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@qoega

qoega commented Sep 13, 2026

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🫧 Superseded by #18, which contains the same compatibility change on top of the current master branch.

@qoega qoega closed this Sep 13, 2026
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