Dear Maintainer,

On 32-bit time_t builds (i386), make_time() in src/libical/icaltime.c rejects
any date after 2038-01-17 (cf. icaltime.c around line 107). This is two days
before the actual limit of a signed 32-bit time_t (2038-01-19T03:14:07 UTC,
INT32_MAX seconds since the epoch).

Rejected dates silently fall through as time_t 0 (1970-01-01) instead of the
correct value or an explicit error.

This directly causes the cyrus-imapd i386 FTBFS tracked in #1142273:
cyrus's icalrecurrenceset_get_utc_timespan() passes INT_MAX as an "unbounded
end" search sentinel to icalcomponent_foreach_recurrence().

On i386, that sentinel collapses to epoch, shrinking the search window to
nothing-after-1970 and silently excluding every occurrence — even for ordinary
events with no relation to 2038 at all.

Upstream fix, tested (i386 build: full regression suite passes, and
cyrus-imapd's actual failing cunit test now passes unmodified):

  4.0 branch: https://github.com/libical/libical/pull/1350
  3.0 branch: https://github.com/libical/libical/pull/1351

Note that Trixie tracks the version 3 branch; and also that upstream dev
`winterz` indicated [0] that it would be a good idea to patch it (without
cutting a new release for version 3).

I am not sure what the best way (or the Debian way) forward is. We could either
wait for upstream to accept the patches / pull requests; or we could just
cherry-pick the patches into Debian itself already.

This would resolve the i386 side of #1142273.

Kind regards,

    Edmund


[0]: https://github.com/libical/libical/pull/1351#issuecomment-5083969752

I can verify this fixes the i386 test bug on cyrus-imapd and have
pushed the fix to git.

I am uploading te changes as NMU to DELAYED/5 because this blocks
bringing back 32 bit support to cyrus-imapd.

Le 2026-07-31 à 08 h 40, Bastian Germann a écrit :

Hello,

No problem, I've checked the patch and it seems ok. I've added some
minor changes to your NMU and will upload the new package today.

Thanks!

We believe that the bug you reported is fixed in the latest version of
libical3, 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 1142814@bugs.debian.org,
and the maintainer will reopen the bug report if appropriate.

Debian distribution maintenance software
pp.
Nicolas Mora <babelouest@debian.org> (supplier of updated libical3 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)
Format: 1.8
Date: Fri, 31 Jul 2026 11:50:07 -0400
Source: libical3
Architecture: source
Version: 3.0.20-3
Distribution: unstable
Urgency: medium
Maintainer: Nicolas Mora <babelouest@debian.org>
Changed-By: Nicolas Mora <babelouest@debian.org>
Closes: 1142814
Changes:
 libical3 (3.0.20-3) unstable; urgency=medium
 .
   [Bastian Germann]
   * Fix 32-bit time_t boundary off by two days (Closes: #1142814)
 .
   [Nicolas Mora]
   * d/control: Update standards version to 4.7.4
   * d/control: Remove Priority option
   * d/control: Upgrade debhelper-compat version to 14
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