Your message dated Mon, 14 Sep 2026 13:33:06 +0200
with message-id <[email protected]>
and subject line Re: Bug#1110535: PATH *is* modified when running pre/post
up/down scripts
has caused the Debian Bug report #1110535,
regarding ifupdown: The execable() function only checks the PATH for helper
scripts like wait-for-ll6.sh, does not include /usr/lib/ifupdown
to be marked as done.
This means that you claim that the problem has been dealt with.
If this is not the case it is now your responsibility to reopen the
Bug report if necessary, and/or fix the problem forthwith.
(NB: If you are a system administrator and have no idea what this
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--
1110535: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1110535
Debian Bug Tracking System
Contact [email protected] with problems
--- Begin Message ---
Package: ifupdown
Version: 0.8.44
Severity: important
Tags: ipv6
X-Debbugs-Cc: [email protected]
When using DHCPv6 with ifupdown it requires a link-local address. After the
interface
is brought up, the wait-for-ll6.sh script is supposed to be used to wait for
the address
to be non-tentative (duplicate address detection has finished) before moving on
to the
next phase. This file lives in /usr/lib/ifupdown by default.
The problem is that the 'inet6' provider (defined in the source in inet6.defn
and compiled
into the binary) uses the execable() function to decide whether to run it or
not:
wait-for-ll6.sh if (var_true("dhcp", ifd) && execable("wait-for-ll6.sh"))
execable() only looks through the PATH if 'program' does not start with a
leading /.
Because /usr/lib/ifupdown is not in the default PATH, the script is never run.
You can see this in action by running 'ifup -v xxxx' with an appropriate
interface configured.
It will show that 'ip link set dev XXXX up' was run, and then immediately runs
the dhcp
client (in my case isc-dhcp-client) and fail because there is no link-local
address.
If you then bring down the interface and make sure to flush the v6 addresses
(ip -6 addr flush XXXX) and run 'PATH=/usr/lib/ifupdown:$PATH ifup -v xxxx' it
will
show that 'ip link set dev XXXX up' is run, then wait-for-ll6.sh, and then the
dhcp
client, and it succeeds.
If debian is going to put these scripts into /usr/lib/ifupdown, then execable()
should look there first, and THEN check the PATH.
-- Package-specific info:
--- up and down scripts installed:
/etc/network/if-down.d:
total 4
-rwxr-xr-x 1 root root 759 Aug 19 2024 resolved
lrwxrwxrwx 1 root root 32 Mar 22 02:06 wpasupplicant ->
../../wpa_supplicant/ifupdown.sh
/etc/network/if-post-down.d:
total 0
lrwxrwxrwx 1 root root 32 Mar 22 02:06 wpasupplicant ->
../../wpa_supplicant/ifupdown.sh
/etc/network/if-pre-up.d:
total 0
lrwxrwxrwx 1 root root 32 Mar 22 02:06 wpasupplicant ->
../../wpa_supplicant/ifupdown.sh
/etc/network/if-up.d:
total 8
-rwxr-xr-x 1 root root 4665 Aug 19 2024 resolved
lrwxrwxrwx 1 root root 32 Mar 22 02:06 wpasupplicant ->
../../wpa_supplicant/ifupdown.sh
-- System Information:
Debian Release: 13.0
APT prefers testing-security
APT policy: (500, 'testing-security'), (500, 'testing')
Architecture: amd64 (x86_64)
Kernel: Linux 6.12.38+deb13-amd64 (SMP w/8 CPU threads; PREEMPT)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE not set
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled
Versions of packages ifupdown depends on:
ii adduser 3.152
ii iproute2 6.15.0-1
ii libc6 2.41-12
Versions of packages ifupdown recommends:
ii isc-dhcp-client [dhcp-client] 4.4.3-P1-8
Versions of packages ifupdown suggests:
pn ppp <none>
pn rdnssd <none>
-- no debconf information
--- End Message ---
--- Begin Message ---
Version: 0.8.44+deb13u1
Hi William,
On Mon, 11 Aug 2025 11:30:40 -0400 William Perry <[email protected]> wrote:
> This seems like a direct result of this change:
>
> commit 1eee7a3040eb7ba295c44beddbfb44abf342ca2c
> Author: Guillem Jover <[email protected]>
> Date: Sun Dec 3 02:51:43 2023 +0100
>
> Use relative names when executing programs
Exactly right. I came to the same conclusion, unfortunately before seeing
your mail. We really need to try to make a dent in the ifupdown bugs pile
at some poing, it's become unweildy :-).
Should be fixed in Trixie since 0.8.44+deb13u1.
Thanks,
--Daniel
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