Debian Bug report logs - #1006445
openssh-server: Killed by seccomp after accepting connection (i386)

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Message #5 received at submit@bugs.debian.org (full text, mbox, reply):

From: Paul Brook <paul@nowt.org>

To: Debian Bug Tracking System <submit@bugs.debian.org>

Subject: openssh-server: Killed by seccomp after accepting connection (i386)

Date: Fri, 25 Feb 2022 14:14:58 +0000

[Message part 1 (text/plain, inline)]

Package: openssh-server
Version: 1:8.9p1-2.1
Severity: important
Tags: patch

Dear Maintainer,

After accepting an ssh connection, the sshd process is killed and I see
the following in dmesg:

audit: type=1326 audit(1645794361.669:40): auid=0 uid=100 gid=65534 ses=1 subj==unconfined pid=8338 comm="sshd" exe="/usr/sbin/sshd" sig=31 arch=40000003 syscall=414 compat=0 ip=0xb7ee3559 code=0x0

Sysycall 414 is ppoll_time64, so I'm guessing this is fallout from
ongoing 2038 fixes.

The attached patch fixes this by adding ppoll_time64 the seccomp sanbox filters,
which seems reasonable as ppoll is already allowed.

-- System Information:
Debian Release: bookworm/sid
  APT prefers unstable
  APT policy: (500, 'unstable'), (1, 'experimental')
Architecture: i386 (i686)

Kernel: Linux 5.16.0-2-686-pae (SMP w/1 CPU thread; PREEMPT)
Locale: LANG=en_GB.UTF-8, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8), LANGUAGE not set
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages openssh-server depends on:
ii  adduser                3.118
ii  debconf [debconf-2.0]  1.5.79
ii  dpkg                   1.21.1
ii  init-system-helpers    1.62
ii  libaudit1              1:3.0.7-1
ii  libc6                  2.33-7
ii  libcom-err2            1.46.5-2
ii  libcrypt1              1:4.4.27-1.1
ii  libgssapi-krb5-2       1.19.2-2
ii  libkrb5-3              1.19.2-2
ii  libpam-modules         1.4.0-11
ii  libpam-runtime         1.4.0-11
ii  libpam0g               1.4.0-11
ii  libselinux1            3.3-1+b1
ii  libssl1.1              1.1.1m-1
ii  libsystemd0            250.3-2
ii  libwrap0               7.6.q-31
ii  lsb-base               11.1.0
ii  openssh-client         1:8.9p1-2.1
ii  openssh-sftp-server    1:8.9p1-2
ii  procps                 2:3.3.17-6
ii  runit-helper           2.10.3
ii  ucf                    3.0043
ii  zlib1g                 1:1.2.11.dfsg-2

Versions of packages openssh-server recommends:
ii  libpam-systemd [logind]  250.3-2
pn  ncurses-term             <none>
ii  xauth                    1:1.1-1

Versions of packages openssh-server suggests:
ii  molly-guard   0.7.2
pn  monkeysphere  <none>
pn  ssh-askpass   <none>
pn  ufw           <none>

-- debconf information:
  ssh/insecure_telnetd:
  ssh/vulnerable_host_keys:
* ssh/use_old_init_script: true
  ssh/new_config: true
  ssh/insecure_rshd:
* openssh-server/permit-root-login: true
  ssh/disable_cr_auth: false
  openssh-server/password-authentication: false
  ssh/encrypted_host_key_but_no_keygen:

[patch (text/plain, attachment)]

Message #10 received at 1006445@bugs.debian.org (full text, mbox, reply):

From: Colin Watson <cjwatson@debian.org>

To: Paul Brook <paul@nowt.org>, 1006445@bugs.debian.org

Subject: Re: Bug#1006445: openssh-server: Killed by seccomp after accepting connection (i386)

Date: Fri, 25 Feb 2022 15:50:05 +0000

On Fri, Feb 25, 2022 at 02:14:58PM +0000, Paul Brook wrote:
> After accepting an ssh connection, the sshd process is killed and I see
> the following in dmesg:
> 
> audit: type=1326 audit(1645794361.669:40): auid=0 uid=100 gid=65534 ses=1 subj==unconfined pid=8338 comm="sshd" exe="/usr/sbin/sshd" sig=31 arch=40000003 syscall=414 compat=0 ip=0xb7ee3559 code=0x0
> 
> Sysycall 414 is ppoll_time64, so I'm guessing this is fallout from
> ongoing 2038 fixes.

More likely fallout from the move from select()/pselect() to
poll()/ppoll() in 8.9.  I suspect this affects most 32-bit Linux
architectures.

> The attached patch fixes this by adding ppoll_time64 the seccomp sanbox filters,
> which seems reasonable as ppoll is already allowed.

Yeah, this looks reasonable to me too, though for tidiness I'd suggest
moving __NR_ppoll_time64 below __NR_ppoll to match the ordering of
__NR_pselect6 and __NR_pselect6_time64.

Would you mind sending this upstream to https://bugzilla.mindrot.org/ ?
I can do it for you if you can't, but it's usually best to have fewer
people in the middle of the discussion.

-- 
Colin Watson (he/him)                              [cjwatson@debian.org]

Message #21 received at 1006445@bugs.debian.org (full text, mbox, reply):

From: Colin Watson <cjwatson@debian.org>

To: 1006445@bugs.debian.org

Cc: Paul Brook <paul@nowt.org>

Subject: Re: Bug#1006445: openssh-server: Killed by seccomp after accepting connection (i386)

Date: Fri, 25 Feb 2022 23:29:56 +0000

Control: forwarded -1 https://bugzilla.mindrot.org/show_bug.cgi?id=3396

On Fri, Feb 25, 2022 at 03:50:05PM +0000, Colin Watson wrote:
> On Fri, Feb 25, 2022 at 02:14:58PM +0000, Paul Brook wrote:
> > The attached patch fixes this by adding ppoll_time64 the seccomp sanbox filters,
> > which seems reasonable as ppoll is already allowed.
> 
> Yeah, this looks reasonable to me too, though for tidiness I'd suggest
> moving __NR_ppoll_time64 below __NR_ppoll to match the ordering of
> __NR_pselect6 and __NR_pselect6_time64.
> 
> Would you mind sending this upstream to https://bugzilla.mindrot.org/ ?
> I can do it for you if you can't, but it's usually best to have fewer
> people in the middle of the discussion.

Looks like somebody else already filed this at
https://bugzilla.mindrot.org/show_bug.cgi?id=3396 with a very similar
patch, so no need to send it again.

-- 
Colin Watson (he/him)                              [cjwatson@debian.org]

Message #26 received at 1006445-submitter@bugs.debian.org (full text, mbox, reply):

From: Colin Watson <cjwatson@debian.org>

To: 1006445-submitter@bugs.debian.org

Subject: Bug#1006445 marked as pending in openssh

Date: Fri, 25 Feb 2022 23:30:37 +0000

Control: tag -1 pending

Hello,

Bug #1006445 in openssh reported by you has been fixed in the
Git repository and is awaiting an upload. You can see the commit
message below and you can check the diff of the fix at:

https://salsa.debian.org/ssh-team/openssh/-/commit/62765c0d4297dae75c91aa1d3191df3e3a1b5893

------------------------------------------------------------------------
Allow ppoll_time64 in seccomp filter

Closes: #1006445
------------------------------------------------------------------------

(this message was generated automatically)
-- 
Greetings

https://bugs.debian.org/1006445

Message #33 received at 1006445-close@bugs.debian.org (full text, mbox, reply):

From: Debian FTP Masters <ftpmaster@ftp-master.debian.org>

To: 1006445-close@bugs.debian.org

Subject: Bug#1006445: fixed in openssh 1:8.9p1-3

Date: Fri, 25 Feb 2022 23:49:11 +0000

Source: openssh
Source-Version: 1:8.9p1-3
Done: Colin Watson <cjwatson@debian.org>

We believe that the bug you reported is fixed in the latest version of
openssh, which is due to be installed in the Debian FTP archive.

A summary of the changes between this version and the previous one is
attached.

Thank you for reporting the bug, which will now be closed.  If you
have further comments please address them to 1006445@bugs.debian.org,
and the maintainer will reopen the bug report if appropriate.

Debian distribution maintenance software
pp.
Colin Watson <cjwatson@debian.org> (supplier of updated openssh package)

(This message was generated automatically at their request; if you
believe that there is a problem with it please contact the archive
administrators by mailing ftpmaster@ftp-master.debian.org)


-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA256

Format: 1.8
Date: Fri, 25 Feb 2022 23:30:49 +0000
Source: openssh
Architecture: source
Version: 1:8.9p1-3
Distribution: unstable
Urgency: medium
Maintainer: Debian OpenSSH Maintainers <debian-ssh@lists.debian.org>
Changed-By: Colin Watson <cjwatson@debian.org>
Closes: 1006445
Changes:
 openssh (1:8.9p1-3) unstable; urgency=medium
 .
   * Allow ppoll_time64 in seccomp filter (closes: #1006445).
Checksums-Sha1:
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 293975449fd17feac51d17ea297ee4dcc9fabe4b 187396 openssh_8.9p1-3.debian.tar.xz
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 622cf1c9ab5e804d39400d97ca2a57324c02773af0f27c60c20dcff22c82ca97 187396 openssh_8.9p1-3.debian.tar.xz
Files:
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 9d751b8e3262ebef8413ae311f8dd7d3 187396 net standard openssh_8.9p1-3.debian.tar.xz

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