On Mon, 25 Apr 2022, Kirill Miazine via Exim-dev wrote:
Beware that the just released RC0 for Exim 4.96 may break your Dovecot
LDA delivery. It did break mine, which is similar to what is described
on https://wiki.dovecot.org/LDA/Exim
Here is the relevant ChangeLog entry:
JH/25 Taint-check exec arguments for transport-initiated external processes.
Previously, tainted values could be used. This affects "pipe", "lmtp" and
"queryprogram" transport, transport-filter, and ETRN commands.
The ${run} expansion is also affected: in "preexpand" mode no part of
the command line may be tainted, in default mode the executable name
may not be tainted.
Jeremy Harris via Exim-announce [2022-04-23 20:23]:
> Notable removals since 4.95:
>
> - the "allow_insecure_tainted_data" main config option and the
> "taint" log_selector. These were previously deprecated.
That seemed like an unfortunate combination to me, so over on the
exim-dev list
https://lists.exim.org/lurker/message/20220426.072833.c68602fb.en.html
I asked:
That isn't a good combination. Please could we keep the option to
allow_insecure_tainted_data if there are new taint features ?
That way we can continue to run live systems while we resolve
these sort of problems.
To which Jeremy replied:
The trouble with that is that it means the coverage of tracking
tainted data use can never be extended.
The commit for that removal is fairly extensive:
- see
https://lists.exim.org/lurker/message/20220427.174941.443df2eb.en.html
for the 27 reverts and 35 files changed.
Given that taint checking appeared in Exim 4.93
and allow_insecure_tainted_data in Exim 4.95,
this (Exim 4.96) would be the first time that allow_insecure_tainted_data
would actually be helpful.
Is it just me, or are others worried about the new taint checking
having unexpected consequences and no way to disable it for debugging ?
--
Andrew C. Aitchison Kendal, UK
[email protected]
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