Hi,
post-install tries to determine whether specific parameters need to be
updated/replaced in the main.cf configuration file.
For this purpose post-install compares several variables to parameter
values obtained via postconf.
While doing so, post-install tries to unexpand mail_version in those
variables.
Unfortunately the invocation of test, including the call to postconf, is
eval'd.
As a result, mail_version will be expanded in the parameter values
obtained via postconf.
Bottom line: mail_version will be unexpanded in the LHS of test, while
being expanded in the RHS of test.
This might lead to main.cf being modified by post-install even if not
necessary/intended.
As "postfix start" invokes post-install via postfix-script, this happens
on every start of Postfix.
The described problem applies to Postfix 3.0.0.
A simple patch to make the comparison more robust by not expanding
mail_version in the RHS of the test is attached.
Regards,
Julian Reich
diff -ru postfix-3.0.0/conf/post-install postfix/conf/post-install
--- postfix-3.0.0/conf/post-install 2014-06-28 14:49:13.000000000 +0200
+++ postfix/conf/post-install 2015-03-28 16:37:57.000000000 +0100
@@ -450,7 +450,8 @@
override=
for name in $MOST_PARAMETERS
do
- eval test \"\$$name\" = \"`$POSTCONF -c $config_directory -h $name`\" || {
+ eval junk=\$$name
+ test "$junk" = `$POSTCONF -c $config_directory -h $name` || {
override=1
break
}
