Kil va_copy(). It isn't present on some ancient systems.

[users/heiko/exim.git] / doc / doc-docbook / spec.xfpt

diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt
index 578485ddd5af95a329c421c55834af69b2642f73..b2c40e48add835c3413090d959ca7dc27013b70a 100644 (file)
--- a/doc/doc-docbook/spec.xfpt
+++ b/doc/doc-docbook/spec.xfpt
@@ -3334,14 +3334,17 @@ proceeding any further along the list, and an error is generated.
 When this option is used by a caller other than root, and the list is different
 from the compiled-in list, Exim gives up its root privilege immediately, and
 runs with the real and effective uid and gid set to those of the caller.
 When this option is used by a caller other than root, and the list is different
 from the compiled-in list, Exim gives up its root privilege immediately, and
 runs with the real and effective uid and gid set to those of the caller.

-
-This behaviour precludes the possibility of testing a configuration using
-&%-C%& right through message reception and delivery, even if the caller is
-root. The reception works, but by that time, Exim is running as the Exim user,
-so when it re-executes to regain privilege for the delivery, the use of &%-C%&
-causes privilege to be lost. However, root can test reception and delivery
-using two separate commands (one to put a message on the queue, using &%-odq%&,
-and another to do the delivery, using &%-M%&).
+However, if a TRUSTED_CONFIG_PREFIX_LIST file is defined in &_Local/Makefile_&,
+root privilege is retained for any configuration file which matches a prefix
+listed in that file.
+
+Leaving TRUSTED_CONFIG_PREFIX_LIST unset precludes the possibility of testing
+a configuration using &%-C%& right through message reception and delivery,
+even if the caller is root. The reception works, but by that time, Exim is
+running as the Exim user, so when it re-executes to regain privilege for the
+delivery, the use of &%-C%& causes privilege to be lost. However, root can
+test reception and delivery using two separate commands (one to put a message
+on the queue, using &%-odq%&, and another to do the delivery, using &%-M%&).

 
 If ALT_CONFIG_PREFIX is defined &_in Local/Makefile_&, it specifies a
 prefix string with which any file named in a &%-C%& command line option
 
 If ALT_CONFIG_PREFIX is defined &_in Local/Makefile_&, it specifies a
 prefix string with which any file named in a &%-C%& command line option


@@ -3371,6 +3374,14 @@ unprivileged caller, it causes Exim to give up its root privilege.
 If DISABLE_D_OPTION is defined in &_Local/Makefile_&, the use of &%-D%& is
 completely disabled, and its use causes an immediate error exit.
 
 If DISABLE_D_OPTION is defined in &_Local/Makefile_&, the use of &%-D%& is
 completely disabled, and its use causes an immediate error exit.
 

+If WHITELIST_D_MACROS is defined in &_Local/Makefile_& then it should be a
+colon-separated list of macros which are considered safe and, if &%-D%& only
+supplies macros from this list, and the values are acceptable, then Exim will
+not give up root privilege if the caller is root, the Exim run-time user, or
+the CONFIGURE_OWNER, if set.  This is a transition mechanism and is expected
+to be removed in the future.  Acceptable values for the macros satisfy the
+regexp: &`^[A-Za-z0-9_/.-]*$`&
+

 The entire option (including equals sign if present) must all be within one
 command line item. &%-D%& can be used to set the value of a macro to the empty
 string, in which case the equals sign is optional. These two commands are
 The entire option (including equals sign if present) must all be within one
 command line item. &%-D%& can be used to set the value of a macro to the empty
 string, in which case the equals sign is optional. These two commands are


@@ -4525,19 +4536,21 @@ A one-off alternate configuration can be specified by the &%-C%& command line
 option, which may specify a single file or a list of files. However, when
 &%-C%& is used, Exim gives up its root privilege, unless called by root (or
 unless the argument for &%-C%& is identical to the built-in value from
 option, which may specify a single file or a list of files. However, when
 &%-C%& is used, Exim gives up its root privilege, unless called by root (or
 unless the argument for &%-C%& is identical to the built-in value from

-CONFIGURE_FILE). &%-C%& is useful mainly for checking the syntax of
-configuration files before installing them. No owner or group checks are done
-on a configuration file specified by &%-C%&.
-
-The Exim user is not trusted to specify an arbitrary configuration file with
-the &%-C%& option to be executed with root privileges. This locks out the
-possibility of testing a configuration using &%-C%& right through message
-reception and delivery, even if the caller is root. The reception works, but
-by that time, Exim is running as the Exim user, so when it re-execs to regain
-privilege for the delivery, the use of &%-C%& causes privilege to be lost.
-However, root can test reception and delivery using two separate commands
-(one to put a message on the queue, using &%-odq%&, and another to do the
-delivery, using &%-M%&).
+CONFIGURE_FILE) or matches a prefix listed in the TRUSTED_CONFIG_PREFIX_LIST
+file. &%-C%& is useful mainly for checking the syntax of configuration files
+before installing them. No owner or group checks are done on a configuration
+file specified by &%-C%&, if root privilege has been dropped.
+
+Even the Exim user is not trusted to specify an arbitrary configuration file
+with the &%-C%& option to be used with root privileges, unless that file is
+listed in the TRUSTED_CONFIG_PREFIX_LIST file. This locks out the possibility
+of testing a configuration using &%-C%& right through message reception and
+delivery, even if the caller is root. The reception works, but by that time,
+Exim is running as the Exim user, so when it re-execs to regain privilege for
+the delivery, the use of &%-C%& causes privilege to be lost. However, root
+can test reception and delivery using two separate commands (one to put a
+message on the queue, using &%-odq%&, and another to do the delivery, using
+&%-M%&).

 
 If ALT_CONFIG_PREFIX is defined &_in Local/Makefile_&, it specifies a
 prefix string with which any file named in a &%-C%& command line option must
 
 If ALT_CONFIG_PREFIX is defined &_in Local/Makefile_&, it specifies a
 prefix string with which any file named in a &%-C%& command line option must


@@ -4552,6 +4565,16 @@ non-privileged user causes Exim to discard its root privilege.
 If DISABLE_D_OPTION is defined in &_Local/Makefile_&, the use of &%-D%& is
 completely disabled, and its use causes an immediate error exit.
 
 If DISABLE_D_OPTION is defined in &_Local/Makefile_&, the use of &%-D%& is
 completely disabled, and its use causes an immediate error exit.
 

+The WHITELIST_D_MACROS option in &_Local/Makefile_& permits the binary builder
+to declare certain macro names trusted, such that root privilege will not
+necessarily be discarded.
+WHITELIST_D_MACROS defines a colon-separated list of macros which are
+considered safe and, if &%-D%& only supplies macros from this list, and the
+values are acceptable, then Exim will not give up root privilege if the caller
+is root, the Exim run-time user, or the CONFIGURE_OWNER, if set.  This is a
+transition mechanism and is expected to be removed in the future.  Acceptable
+values for the macros satisfy the regexp: &`^[A-Za-z0-9_/.-]*$`&
+

 Some sites may wish to use the same Exim binary on different machines that
 share a file system, but to use different configuration files on each machine.
 If CONFIGURE_FILE_USE_NODE is defined in &_Local/Makefile_&, Exim first
 Some sites may wish to use the same Exim binary on different machines that
 share a file system, but to use different configuration files on each machine.
 If CONFIGURE_FILE_USE_NODE is defined in &_Local/Makefile_&, Exim first


@@ -15197,9 +15220,10 @@ is used in a system filter.
 
 .option system_filter_user main string unset
 .cindex "uid (user id)" "system filter"
 
 .option system_filter_user main string unset
 .cindex "uid (user id)" "system filter"

-If this option is not set, the system filter is run in the main Exim delivery
-process, as root. When the option is set, the system filter runs in a separate
-process, as the given user. Unless the string consists entirely of digits, it
+If this option is set to root, the system filter is run in the main Exim
+delivery process, as root.  Otherwise, the system filter runs in a separate
+process, as the given user, defaulting to the Exim run-time user.
+Unless the string consists entirely of digits, it

 is looked up in the password data. Failure to find the named user causes a
 configuration error. The gid is either taken from the password data, or
 specified by &%system_filter_group%&. When the uid is specified numerically,
 is looked up in the password data. Failure to find the named user causes a
 configuration error. The gid is either taken from the password data, or
 specified by &%system_filter_group%&. When the uid is specified numerically,


@@ -15207,8 +15231,7 @@ specified by &%system_filter_group%&. When the uid is specified numerically,
 
 If the system filter generates any pipe, file, or reply deliveries, the uid
 under which the filter is run is used when transporting them, unless a
 
 If the system filter generates any pipe, file, or reply deliveries, the uid
 under which the filter is run is used when transporting them, unless a

-transport option overrides. Normally you should set &%system_filter_user%& if
-your system filter generates these kinds of delivery.
+transport option overrides.

 
 
 .option tcp_nodelay main boolean true
 
 
 .option tcp_nodelay main boolean true


@@ -33797,8 +33820,11 @@ which only root has access, this guards against someone who has broken
 into the Exim account from running a privileged Exim with an arbitrary
 configuration file, and using it to break into other accounts.
 .next
 into the Exim account from running a privileged Exim with an arbitrary
 configuration file, and using it to break into other accounts.
 .next

-If a non-default configuration file is specified with &%-C%&, or macros are
-given with &%-D%&, then root privilege is retained only if the caller of Exim
+If a non-trusted configuration file (i.e. the default configuration file or
+one which is trusted by virtue of matching a prefix listed in the
+TRUSTED_CONFIG_PREFIX_LIST file) is specified with &%-C%&, or if macros are
+given with &%-D%& (but see the next item),
+then root privilege is retained only if the caller of Exim

 is root. This locks out the possibility of testing a configuration using &%-C%&
 right through message reception and delivery, even if the caller is root. The
 reception works, but by that time, Exim is running as the Exim user, so when
 is root. This locks out the possibility of testing a configuration using &%-C%&
 right through message reception and delivery, even if the caller is root. The
 reception works, but by that time, Exim is running as the Exim user, so when


@@ -33806,6 +33832,14 @@ it re-execs to regain privilege for the delivery, the use of &%-C%& causes
 privilege to be lost. However, root can test reception and delivery using two
 separate commands.
 .next
 privilege to be lost. However, root can test reception and delivery using two
 separate commands.
 .next

+The WHITELIST_D_MACROS build option declares some macros to be safe to override
+with &%-D%& if the real uid is one of root, the Exim run-time user or the
+CONFIGURE_OWNER, if defined.  The potential impact of this option is limited by
+requiring the run-time value supplied to &%-D%& to match a regex that errs on
+the restrictive side.  Requiring build-time selection of safe macros is onerous
+but this option is intended solely as a transition mechanism to permit
+previously-working configurations to continue to work after release 4.73.
+.next

 If DISABLE_D_OPTION is defined, the use of the &%-D%& command line option
 is disabled.
 .next
 If DISABLE_D_OPTION is defined, the use of the &%-D%& command line option
 is disabled.
 .next


@@ -33861,9 +33895,12 @@ uid and gid in the following cases:
 If the &%-C%& option is used to specify an alternate configuration file, or if
 the &%-D%& option is used to define macro values for the configuration, and the
 calling process is not running as root, the uid and gid are changed to those of
 If the &%-C%& option is used to specify an alternate configuration file, or if
 the &%-D%& option is used to define macro values for the configuration, and the
 calling process is not running as root, the uid and gid are changed to those of

- the calling process.
+the calling process.

 However, if DISABLE_D_OPTION is defined in &_Local/Makefile_&, the &%-D%&
 option may not be used at all.
 However, if DISABLE_D_OPTION is defined in &_Local/Makefile_&, the &%-D%&
 option may not be used at all.

+If WHITELIST_D_MACROS is defined in &_Local/Makefile_&, then some macro values
+can be supplied if the calling process is running as root, the Exim run-time
+user or CONFIGURE_OWNER, if defined.

 .next
 .oindex "&%-be%&"
 .oindex "&%-bf%&"
 .next
 .oindex "&%-be%&"
 .oindex "&%-bf%&"