VMOD(UNIX)                                                          VMOD(UNIX)

       VMOD unix - Utilities for Unix domain sockets

          import unix [as name] [from "path"]

          STRING user()

          STRING group()

          INT uid()

          INT gid()

       This VMOD provides information about the credentials of the peer
       process (user and group of the process owner) that is connected to a
       Varnish listener via a Unix domain socket, if the platform supports it.


          import unix;

          sub vcl_recv {
                # Return "403 Forbidden" if the connected peer is
                # not running as the user "trusteduser".
                if (unix.user() != "trusteduser") {
                        return( synth(403) );

                # Require the connected peer to run in the group
                # "trustedgroup".
                if (unix.group() != "trustedgroup") {
                        return( synth(403) );

                # Require the connected peer to run under a specific numeric
                # user id.
                if (unix.uid() != 4711) {
                        return( synth(403) );

                # Require the connected peer to run under a numeric group id.
                if (unix.gid() != 815) {
                        return( synth(403) );

       Obtaining the peer credentials is possible on a platform that supports
       one of the following:

       · getpeereid(3) (such as FreeBSD and other BSD-derived systems)

       · the socket option SO_PEERCRED for getsockopt(2) (Linux)

       · getpeerucred(3C) (SunOS and descendants)

       On SunOS and friends, the PRIV_PROC_INFO privilege set is added to the
       Varnish child process while the VMOD is loaded, see setppriv(2).

       On most platforms, the value returned is the effective user or group
       that was valid when the peer process initiated the connection.

   STRING user()
       Return the user name of the peer process owner.

   STRING group()
       Return the group name of the peer process owner.

   INT uid()
       Return the numeric user id of the peer process owner.

   INT gid()
       Return the numeric group id of the peer process owner.

       All functions in this VMOD are subject to the following constraints:

       · None of them may be called in vcl_init{} or vcl_fini{}. If one of
         them is called in vcl_init{}, then the VCL program will fail to load,
         with an error message from the VMOD.

       · If called on a platform that is not supported, then VCL failure is
         invoked. An error message is written to the log (with the VCL_Error
         tag), and for all VCL subroutines except for vcl_synth{}, control is
         directed immediately to vcl_synth{}, with the response status set to
         503 and the reason string set to "VCL failed".

         If the failure occurs during vcl_synth{}, then vcl_synth{} is
         aborted, and the the response line "503 VCL failed" is sent.

       · If the current listener is not a Unix domain socket, or if the
         attempt to read credentials fails, then a VCL_Error message is
         written to the log. The STRING functions (unix.user() and
         unix.group()) return NULL, while the INT functions (unix.uid() and
         unix.gid()) return -1.

       · varnishd(1)

       · vcl(7)

       · getpeereid(3)

       · getsockopt(2)

       · getpeerucred(3C)

       · setppriv(2)

          This document is licensed under the same conditions as Varnish itself.
          See LICENSE for details.

          Authors: Geoffrey Simmons <geoffrey.simmons@uplex.de>

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