Bug#1142354: sshd-session built without crypt(), breaking UsePAM=no password auth

Alexander Fisher <[email protected]> Sat, 18 Jul 2026 14:28:43 +0100
Newsgroups gmane.linux.debian.devel.ssh
Message-ID <CAC34VL7UkzCD80BA1Qj5EugkN-cAmwCYVVH7zKbQJsjBcnyebg__29159.5095930219$1784381488$gmane$org@mail.gmail.com>
--000000000000a1b6ab0656e2a747
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

Package: src:openssh
Version: 1:10.4p1-1
Severity: important

sshd-session is built without crypt() support, so password
authentication fails when UsePAM is set to "no" =E2=80=94 sshd logs "Failed
password" for a correct password. UsePAM yes is unaffected (that path
goes through pam_unix, which links libcrypt itself).

The build no longer detects crypt: [1]

  checking for crypt in -lcrypt... no
  checking for crypt... no

This is a side effect of libc6-dev dropping its libcrypt-dev dependency
(glibc 2.42-7) [2][3]. openssh only ever got libcrypt-dev transitively, so
it's
now absent from the build chroot and crypt() is compiled out. It builds
cleanly (no FTBFS), which is why the archive rebuild for that transition
didn't flag it.

trixie (1:10.0p1-7+deb13u4) still links libcrypt and is fine. [4]

The fix is to add libcrypt-dev to Build-Depends. I'll submit an MR with
that plus a regression test once my Salsa account is approved. Same issue
hit Ubuntu 26.04 (LP: #2161162). [5]

[1] -
https://buildd.debian.org/status/fetch.php?pkg=3Dopenssh&arch=3Damd64&ver=
=3D1%3A10.4p1-1&stamp=3D1783366343&raw=3D0
[2] -
https://salsa.debian.org/glibc-team/glibc/-/commit/10c4a331fb977ae5ae7255e9=
ee1c9c133f9d9da9
[3] - https://www.freexian.com/blog/debian-contributions-04-2025/
[4] -
https://buildd.debian.org/status/fetch.php?pkg=3Dopenssh&arch=3Damd64&ver=
=3D1%3A10.0p1-7%2Bdeb13u4&stamp=3D1778093735&raw=3D0
[5] - https://bugs.launchpad.net/ubuntu/+source/openssh/+bug/2161162

--000000000000a1b6ab0656e2a747
Content-Type: text/html; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

<div dir=3D"ltr">Package: src:openssh<br>Version: 1:10.4p1-1<br>Severity: i=
mportant<br><br>sshd-session is built without crypt() support, so password<=
br>authentication fails when UsePAM is set to &quot;no&quot; =E2=80=94 sshd=
 logs &quot;Failed<br>password&quot; for a correct password. UsePAM yes is =
unaffected (that path<br>goes through pam_unix, which links libcrypt itself=
).<br><br>The build no longer detects crypt: [1]<br><br>=C2=A0 checking for=
 crypt in -lcrypt... no<br>=C2=A0 checking for crypt... no<br><br>This is a=
 side effect of libc6-dev dropping its libcrypt-dev dependency<br>(glibc 2.=
42-7) [2][3]. openssh only ever got libcrypt-dev transitively, so it&#39;s<=
br>now absent from the build chroot and crypt() is compiled out. It builds<=
br>cleanly (no FTBFS), which is why the archive rebuild for that transition=
<br>didn&#39;t flag it.<br><br>trixie (1:10.0p1-7+deb13u4) still links libc=
rypt and is fine. [4]<br><br>The fix is to add libcrypt-dev to Build-Depend=
s. I&#39;ll submit an MR with<br>that plus a regression test once my Salsa =
account is approved. Same issue<br>hit Ubuntu 26.04 (LP: #2161162). [5]<br>=
<br>[1] -=C2=A0<a href=3D"https://buildd.debian.org/status/fetch.php?pkg=3D=
openssh&amp;arch=3Damd64&amp;ver=3D1%3A10.4p1-1&amp;stamp=3D1783366343&amp;=
raw=3D0">https://buildd.debian.org/status/fetch.php?pkg=3Dopenssh&amp;arch=
=3Damd64&amp;ver=3D1%3A10.4p1-1&amp;stamp=3D1783366343&amp;raw=3D0</a><br>[=
2] -=C2=A0<a href=3D"https://salsa.debian.org/glibc-team/glibc/-/commit/10c=
4a331fb977ae5ae7255e9ee1c9c133f9d9da9">https://salsa.debian.org/glibc-team/=
glibc/-/commit/10c4a331fb977ae5ae7255e9ee1c9c133f9d9da9</a><br>[3] -=C2=A0<=
a href=3D"https://www.freexian.com/blog/debian-contributions-04-2025/">http=
s://www.freexian.com/blog/debian-contributions-04-2025/</a><br>[4] -=C2=A0<=
a href=3D"https://buildd.debian.org/status/fetch.php?pkg=3Dopenssh&amp;arch=
=3Damd64&amp;ver=3D1%3A10.0p1-7%2Bdeb13u4&amp;stamp=3D1778093735&amp;raw=3D=
0">https://buildd.debian.org/status/fetch.php?pkg=3Dopenssh&amp;arch=3Damd6=
4&amp;ver=3D1%3A10.0p1-7%2Bdeb13u4&amp;stamp=3D1778093735&amp;raw=3D0</a><b=
r>[5] -=C2=A0<a href=3D"https://bugs.launchpad.net/ubuntu/+source/openssh/+=
bug/2161162">https://bugs.launchpad.net/ubuntu/+source/openssh/+bug/2161162=
</a><br></div>

--000000000000a1b6ab0656e2a747--