*** buffer overflow detected ***: find terminated

[Jay R. Wren]

When running find with -printf "%T+ %p\n"

The -printf "%T+ %p\n" worked in previous versions. This is a new bug in 17.10.

```
> find . -printf "%A+ %p\n"
*** buffer overflow detected ***: find terminated
Aborted (core dumped)
```

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[C de-Avillez (hggdh2)]

correcting package. /usr/bin/find belong to the findutils package.

[Henning Meyer (henning.meyer)]

I can confirm the bug:

There is a blatant stack overflow in the ubuntu 17.10 sources (findutils-4.6.0+git+20170729):
file "find/print.c", function "static char* format_date", line 614 and following

char fmt[6];
/* a few lines later */
strcpy(fmt, "%Y-%m-%d+%T");

that is string is longer than 5 characters
that call should be strncpy anyway

the non-crashing versions (previous ubuntu, also official GNU sources 4.6.0) instead have

strcpy (fmt, "%F+%T");

which does fit exactly into a six byte buffer

The obvious fix is to increase the size of fmt to hold the longer string

there is a comment in the new sources, explaining the motivation

      /* Avoid %F, some Unix versions lack it. For example:
         HP Tru64 UNIX V5.1B (Rev. 2650); Wed Feb 17 22:59:59 CST 2016
         Also, some older HP-UX versions expand %F as the full month (like %B).
         Reported by Steven M. Schweda <email address hidden> */

[Henning Meyer (henning.meyer)]

I just checked the GNU git sources (https://git.savannah.gnu.org/git/findutils.git)

the bug was fixed upstream

commit febde26dd0e66dda5d4060fa29b85443ddc6a865
Author: Bernhard Voelker <email address hidden>
Date: Mon Aug 28 23:15:12 2017 +0200

    find: avoid buffer-overflow with -printf '%T+'

    * find/print.c (format_date): Increase size of local variable
    FMT to match the longest possible content.

    Fixes https://bugs.debian.org/873032 reported upstream by
    Andreas Metzler in https://savannah.gnu.org/bugs/?51841;
    fix proposed by Kamil Dudka.

    Bug introduced in commit v4.6.0-111-g95816b2, so no released version
    ever saw this; therefore not adding a NEWS entry.

commit 95816b29d46fb6b64754d4a66e7d918b3f134a1f
Author: James Youngman <email address hidden>
Date: Sun Jul 23 22:19:42 2017 +0100

    find: avoid strftime's non-portable %F specifier.

    * find/print.c (format_date): Avoid passing %F to strftime since
    some implementation lack it. Pass the synonymous %Y-%m-%d
    instead. This fixes a bug manifesting on HP Tru64 UNIX V5.1B.
    Reported by Steven M. Schweda <email address hidden>.