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Bug 1724672 - ssh_session_has_known_hosts_entry() regressed in 0.8.91
Summary: ssh_session_has_known_hosts_entry() regressed in 0.8.91
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Red Hat Enterprise Linux 8
Classification: Red Hat
Component: libssh
Version: 8.1
Hardware: Unspecified
OS: Unspecified
high
urgent
Target Milestone: rc
: 8.1
Assignee: Anderson Sasaki
QA Contact: Ivan Nikolchev
URL:
Whiteboard:
Depends On:
Blocks: 1720267
TreeView+ depends on / blocked
 
Reported: 2019-06-27 13:57 UTC by Martin Pitt
Modified: 2020-11-14 07:17 UTC (History)
4 users (show)

Fixed In Version: libssh-0.9.0-3.el8
Doc Type: If docs needed, set a value
Doc Text:
Clone Of:
Environment:
Last Closed: 2019-11-05 22:36:03 UTC
Type: Bug
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)
reproducer (980 bytes, text/x-csrc)
2019-06-27 13:57 UTC, Martin Pitt 		no flags Details
View All


Links
System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHBA-2019:3657 0 None None None 2019-11-05 22:36:15 UTC

Description Martin Pitt 2019-06-27 13:57:51 UTC 
Created attachment 1585180 [details]
reproducer

Description of problem: The latest version 0.8.91 in RHEL 8.1 (and now also Fedora Rawhide) breaks known hosts handling. Hosts are now considered unknown even when 


Version-Release number of selected component (if applicable):

libssh-0.8.91-0.1.el8

How reproducible: Always


Steps to Reproduce:
1. Generate a local ./knownhosts file with
   ssh -o UserKnownHostsFile=./knownhosts 127.0.0.1
   No need to log in, just confirm the host key.
2. Build and run the attached reproducer, which exercises ssh_session_has_known_hosts_entry:
   gcc -Wall -o client-knownhost client-knownhost.c  -lssh && ./client-knownhost

Actual results:

Validate that with libssh up to 0.8.7, the host is known, i. e. that you did the ./knownhosts

[2019/06/27 15:27:32.815499, 2] ssh_connect:  libssh 0.8.7 (c) 2003-2018 Aris Adamantiadis, Andreas Schneider and libssh contributors. Distributed under the LGPL, please refer to COPYING file for information about your rights, using threading threads_pthread
[2019/06/27 15:27:32.815815, 2] ssh_socket_connect:  Nonblocking connection socket: 3
[2019/06/27 15:27:32.815883, 2] ssh_connect:  Socket connecting, now waiting for the callbacks to work
[2019/06/27 15:27:32.815931, 1] socket_callback_connected:  Socket connection callback: 1 (0)
[2019/06/27 15:27:32.829473, 1] ssh_client_connection_callback:  SSH server banner: SSH-2.0-OpenSSH_8.0
[2019/06/27 15:27:32.829528, 1] ssh_analyze_banner:  Analyzing banner: SSH-2.0-OpenSSH_8.0
[2019/06/27 15:27:32.829554, 1] ssh_analyze_banner:  We are talking to an OpenSSH client version: 8.0 (80000)
[2019/06/27 15:27:32.829747, 1] ssh_known_hosts_read_entries:  Failed to open the known_hosts file '/builddir/.ssh/known_hosts': No such file or directory
[2019/06/27 15:27:32.832632, 2] ssh_kex_select_methods:  Negotiated curve25519-sha256,ecdsa-sha2-nistp256,aes256-ctr,aes256-ctr,hmac-sha2-256,hmac-sha2-256,none,none,,
[2019/06/27 15:27:32.844292, 2] ssh_packet_dh_reply:  Received SSH_KEXDH_REPLY
[2019/06/27 15:27:32.848752, 2] ssh_client_curve25519_reply:  SSH_MSG_NEWKEYS sent
[2019/06/27 15:27:32.848811, 2] ssh_packet_newkeys:  Received SSH_MSG_NEWKEYS
[2019/06/27 15:27:32.849191, 2] ssh_packet_newkeys:  Signature verified and valid
[2019/06/27 15:27:32.849289, 1] ssh_known_hosts_read_entries:  Failed to open the known_hosts file '/builddir/.ssh/known_hosts': No such file or directory
host known: 1


with libssh 0.8.91, it is not known:

[2019/06/27 15:29:50.895746, 1] ssh_config_parse_line:  line 3: Unsupported Match keyword 'final', skipping
[2019/06/27 15:29:50.895880, 2] ssh_config_parse_line:  Unapplicable option: ForwardX11Trusted, line: 12
[2019/06/27 15:29:50.895957, 2] ssh_config_parse_line:  Unapplicable option: SendEnv, line: 15
[2019/06/27 15:29:50.895997, 2] ssh_config_parse_line:  Unapplicable option: SendEnv, line: 16
[2019/06/27 15:29:50.896033, 2] ssh_config_parse_line:  Unapplicable option: SendEnv, line: 17
[2019/06/27 15:29:50.896056, 2] ssh_config_parse_line:  Unapplicable option: SendEnv, line: 18
[2019/06/27 15:29:50.896097, 2] ssh_connect:  libssh 0.8.91 (c) 2003-2019 Aris Adamantiadis, Andreas Schneider and libssh contributors. Distributed under the LGPL, please refer to COPYING file for information about your rights, using threading threads_pthread
[2019/06/27 15:29:50.896312, 2] ssh_socket_connect:  Nonblocking connection socket: 3
[2019/06/27 15:29:50.896379, 2] ssh_connect:  Socket connecting, now waiting for the callbacks to work
[2019/06/27 15:29:50.896430, 1] socket_callback_connected:  Socket connection callback: 1 (0)
[2019/06/27 15:29:50.908453, 2] ssh_client_connection_callback:  SSH server banner: SSH-2.0-OpenSSH_8.0
[2019/06/27 15:29:50.908497, 2] ssh_analyze_banner:  Analyzing banner: SSH-2.0-OpenSSH_8.0
[2019/06/27 15:29:50.908517, 2] ssh_analyze_banner:  We are talking to an OpenSSH client version: 8.0 (80000)
[2019/06/27 15:29:50.908684, 1] ssh_known_hosts_read_entries:  Failed to open the known_hosts file '/builddir/.ssh/known_hosts': No such file or directory
[2019/06/27 15:29:50.910906, 2] ssh_kex_select_methods:  Negotiated curve25519-sha256,ecdsa-sha2-nistp256,aes256-gcm,aes256-gcm,hmac-sha2-256-etm,hmac-sha2-256-etm,none,none,,
[2019/06/27 15:29:50.924347, 2] ssh_init_rekey_state:  Set rekey after 4294967296 blocks
[2019/06/27 15:29:50.924399, 2] ssh_init_rekey_state:  Set rekey after 4294967296 blocks
[2019/06/27 15:29:50.924417, 2] ssh_packet_client_curve25519_reply:  SSH_MSG_NEWKEYS sent
[2019/06/27 15:29:50.924433, 2] ssh_packet_newkeys:  Received SSH_MSG_NEWKEYS
[2019/06/27 15:29:50.924743, 2] ssh_packet_newkeys:  Signature verified and valid
host known: -1

(The /builddir is because I'm running this in mock).

-1 means SSH_KNOWN_HOSTS_NOT_FOUND. This happens also with specifying an absolute instead of relative path, and also with SSH_OPTIONS_KNOWNHOSTS instead of _GLOBAL_KNOWNHOSTS.

Expected results: Host is known with 0.8.91


Additional info:
Comment 2 Martin Pitt 2019-06-27 19:57:18 UTC 
Thanks Anderson! This affects package builds, where my .spec can't just create an /etc/ssh/ssh_known_hosts. But fixing this in the next days is certainly fast enough, we still have some time in RHEL 8.1 to land stuff. Thanks!
Comment 3 Anderson Sasaki 2019-07-01 15:17:59 UTC 
This should be fixed by libssh-0.9.0-1 in current Fedora rawhide.
Comment 12 errata-xmlrpc 2019-11-05 22:36:03 UTC 
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHBA-2019:3657
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