tree b61e394ccd4ce6173be96d044394fb12b03197b9
parent 2819210a8328ff60505e499acf9f8bc323bec840
author Willy Tarreau <w@1wt.eu> 1630602187 +0200
committer Willy Tarreau <w@1wt.eu> 1630603423 +0200
encoding latin1

BUG/MINOR: vars: improve accuracy of the rules used to check expression validity

The set-var() expression naturally checks whether expressions are valid
in the context of the rule, but it fails to differentiate frontends from
backends. As such for tcp-content and http-request rules, it will only
accept frontend-compatible sample-fetches, excluding those declared with
SMP_UES_BKEND (a few such as be_id, be_name). For the response it accepts
the backend-compatible expressions only, though it seems that there are
no sample-fetch function that are valid only in the frontend's content,
so that should not cause any problem.

Note that while allowing valid configs to be used, the fix might also
uncover some incorrect configurations where some expressions currently
return nothing (e.g. something depending on frontend declared in a
backend), and which could be rejected, but there does not seem to be
any such keyword. Thus while it should be backported, better not backport
it too far (2.4 and possibly 2.3 only).