[Bug 1875167] Re: eoan, libssh2 1.8.0-2.1build1: postponed key auth error

[Launchpad Bug Tracker]

[Expired for libssh2 (Ubuntu) because there has been no activity for 60
days.]

** Changed in: libssh2 (Ubuntu)
       Status: Incomplete => Expired

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Title:
  eoan, libssh2 1.8.0-2.1build1: postponed key auth error

Status in libssh2 package in Ubuntu:
  Expired

Bug description:
  * My system

  -----------------8<---------------------------------------------------
  $ lsb_release -rd
  Description:	Ubuntu 19.10
  Release:	19.10
  -----------------8<---------------------------------------------------

  * Package version

  -----------------8<---------------------------------------------------
  $ apt-cache policy libssh2-1
  libssh2-1:
    Installed: 1.8.0-2.1build1
    Candidate: 1.8.0-2.1build1
    Version table:
   *** 1.8.0-2.1build1 500
          500 http://ru.archive.ubuntu.com/ubuntu eoan/universe amd64 Packages
          100 /var/lib/dpkg/status
  -----------------8<---------------------------------------------------

  
  * Expected behaviour
  'php-ssh2' that depends on 'libssh2' authenticates with public key successfully with OpenSSH server.

  * Actual behaviour
  'php-ssh2' fails to authenticate with OpenSSH server using RSA public key.  When used with manually compiled 'libssh2' with OpenSSL, authentication works fine.

  * Problem description

  I found that when 'php-ssh2' is used with 'libssh2 1.8.0-2.1build1' it
  fails to authenticate with an OpenSSH server.

  Here's my test code:
  -----------------8<---------------------------------------------------
  <?php

  $ssh_connection = ssh2_connect("localhost", "22");

  ssh2_auth_pubkey_file($ssh_connection, "avp",
                        "./test-key.pub",
                        "./test-key");

  ?>
  -----------------8<---------------------------------------------------

  When I try to run the code, it exists with the following error:
  -----------------8<---------------------------------------------------
  PHP Warning:  ssh2_auth_pubkey_file(): Authentication failed for avp using public key: Callback returned error [...]
  -----------------8<---------------------------------------------------

  The error I see in the sshd logs is the following:
  -----------------8<---------------------------------------------------
  апр 26 11:38:43 desktop sshd[12466]: debug1: no match: libssh2_1.8.0 PHP
  [...]
  апр 26 11:38:44 desktop sshd[12466]: debug3: mm_answer_keyallowed: publickey authentication test: ED25519 key is allowed
  апр 26 11:38:44 desktop sshd[12466]: debug3: mm_request_send entering: type 23
  апр 26 11:38:44 desktop sshd[12466]: debug3: send packet: type 60 [preauth]
  апр 26 11:38:44 desktop sshd[12466]: debug2: userauth_pubkey: authenticated 0 pkalg ssh-ed25519 [preauth]
  апр 26 11:38:44 desktop sshd[12466]: debug3: user_specific_delay: user specific delay 0.000ms [preauth]
  апр 26 11:38:44 desktop sshd[12466]: debug3: ensure_minimum_time_since: elapsed 7.440ms, delaying 1.005ms (requested 8.445ms) [preauth]
  апр 26 11:38:44 desktop sshd[12466]: Postponed publickey for avp from 127.0.0.1 port 39858 ssh2 [preauth]
  апр 26 11:38:44 desktop sshd[12466]: debug3: receive packet: type 1 [preauth]
  апр 26 11:38:44 desktop sshd[12466]: Received disconnect from 127.0.0.1 port 39858:11: PECL/ssh2 (http://pecl.php.net/packages/ssh2) [preauth]
  -----------------8<---------------------------------------------------

  To trace down the error, I downloaded 'php-ssh2' sources, added some
  debug traces, built it and tried to run my test code again.  It turns
  out that 'libssh2_userauth_publickey_fromfile_ex' from 'libssh2'
  returns code -19 (LIBSSH2_ERROR_PUBLICKEY_UNVERIFIED).

  After some investigation I tried to build different versions of 'libssh2' from sources.  It turned out that when I build 'libssh' version 1.9.0 with OpenSSH, the errors are gone:
  -----------------8<---------------------------------------------------
  $ git clone https://github.com/libssh2/libssh2.git
  $ cd libssh2
  $ git checkout libssh2-1.9.0
  $ mkdir build
  $ cd build
  $ cmake -DBUILD_SHARED_LIBS=ON -DCRYPTO_BACKEND=OpenSSL ../
  $ make -j4
  -----------------8<---------------------------------------------------

  On the other hand, when I build 'libssh2' versions 1.8.0, 1.8.1, 1.8.2
  from sources with OpenSSL, I see the "Postponed publickey" error
  again.

  Furthermore, if I try to use 1.9.0 with Libgcrypt, I see the error
  too.

  My conclusion is that 'php-ssh2' in Ubuntu 19.10 does not work
  properly with the default packaged version of 'libssh2' (and probably
  other packages that depend on 'libssh2' as well.)

  If I missed something, please feel free to correct me.

  Thanks.

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