Subject: bug#497: libc6: Permission denied, intermittent in execve

From: Alessandro Vesely <[email-masked]>
Date: Mon, 27 Jul 2020 10:25:27 +0200

Package: libc6
Version: GNU C Library (Debian GLIBC 2.28-10) stable release version 2.28.
Severity: normal

Dear Maintainer,

in certain situations, execve fails setting errno to EACCESS.  The same
program, launched by the same user in different ways, succeeds or fails
according to preceding actions.

None of the failure conditions for EACCESS is met.

The case at hand happens with an old version of Thunderbird and a LibreOffice
attachment.  After saving the attachment, Thunderbird execs gio-launch-desktop.
The latter tries to exec libreoffice6.4 and fails.

I strace'd the full arguments used in the failed execve(), and copied them to a
simple C program which runs just that execve() call.  When called from the
command line, the program succeeds.  Then I replaced the gio-launch-desktop
executable with my straw men.  When called from Thunderbird, the program fails.

See also:
https://unix.stackexchange.com/questions/600174/permission-denied-intermittent-
in-execve

-- System Information:
Distributor ID: Debian
Description:    Devuan GNU/Linux 3 (beowulf)
Release:        3
Codename:       beowulf
Architecture: x86_64

Kernel: Linux 4.19.0-9-amd64 (SMP w/8 CPU cores)
Locale: LANG=en_IE.UTF-8, LC_CTYPE=en_IE.UTF-8 (charmap=UTF-8),
LANGUAGE=en_IE.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/bash