Add TRUSTED_CONFIG_PREFIX_FILE option

[exim.git] / doc / doc-src / FAQ.src

diff --git a/doc/doc-src/FAQ.src b/doc/doc-src/FAQ.src
index b53070e07692b6cf59c54cb214161d0d90bdfe22..461b1a608c0d133339a5f9740437762116af767e 100644 (file)
--- a/doc/doc-src/FAQ.src
+++ b/doc/doc-src/FAQ.src
@@ -851,7 +851,9 @@ A0044: Exim has been unable to create a file in its spool area in which to
 
        If you are running Exim with an alternate configuration file using a
        command such as \"exim -C altconfig..."\, remember that the use of -C
 
        If you are running Exim with an alternate configuration file using a
        command such as \"exim -C altconfig..."\, remember that the use of -C

-       takes away Exim's root privilege.
+       takes away Exim's root privilege, unless \\TRUSTED_CONFIG_PREFIX_FILE\\
+       is set in \(Local/Makefile)\ and the corresponding file contains a
+       prefix which matches the alternative configuration file being used.

 
        Check that you have defined the spool directory correctly by running
 
 
        Check that you have defined the spool directory correctly by running
 


@@ -1147,25 +1149,17 @@ Q0065: When (as \/root/\) I use -C to run Exim with an alternate configuration
        trying to run an \%autoreply%\ transport. Why is this?
 
 A0065: When Exim is called with -C, it passes on -C to any instances of itself
        trying to run an \%autoreply%\ transport. Why is this?
 
 A0065: When Exim is called with -C, it passes on -C to any instances of itself

-       that it calls (so that the whole sequence uses the same config file). If
-       it's running as \/exim/\ when it does this, all is well. However, if it
-       happens as a consequence of a non-privileged user running \%autoreply%\,
-       the called Exim gives up its root privilege. Then it can't write to the
-       spool.
-
-       This means that you can't use -C (even as \/root/\) to run an instance of
-       Exim that is going to try to run \%autoreply%\ from a process that is
-       neither \/root/\ nor \/exim/\. Because of the architecture of Exim (using
-       re-execs to regain privilege), there isn't any way round this
-       restriction. Therefore, the only way you can make this scenario work is
-       to run the \%autoreply%\ transport as \/exim/\ (that is, the user that
-       owns the Exim spool files). This may be satisfactory for autoreplies
-       that are essentially system-generated, but of course is no good for
-       autoreplies from unprivileged users, where you want the \%autoreply%\
-       transport to be run as the user. To get that to work with an alternate
-       configuration, you'll have to use two Exim binaries, with different
-       configuration file names in each. See S001 for a script that patches
-       the configuration name in an Exim binary.
+       that it calls (so that the whole sequence uses the same config file).
+       However, Exim gives up its root privilege if any user except \/root\/
+       passes a -C option to use a non-default configuration file, and that
+       includes the case where Exim re-execs itself to regain root privilege.
+       Thus it can't write to the spool.
+
+       The fix for this is to use the \\TRUSTED_CONFIG_PREFIX_LIST\\ build-time
+       option. This defines a file containing a list of 'trusted' prefixes for
+       configuration files. Any configuration file specified with -C, if it
+       matches a prefix listed in that file, will be used without dropping root
+       privileges (as long as it is not writeable by a non-root user).

 
 
 Q0066: What does the message \*unable to set gid=xxx or uid=xxx*\ mean?
 
 
 Q0066: What does the message \*unable to set gid=xxx or uid=xxx*\ mean?