[ic] vlink MINIVEND_SOCKET patch

[Peter Ajamian]

On 6/05/20 5:30 am, Peter wrote:
>>> Also, if strlen(lsocket) > sizeof(sa.sun_path), a truncated copy 
>>> would end up being bunko, since it won’t refer to an actual valid 
>>> path; would it be better to just check if strlen(lsocket) > 
>>> sizeof(sa.sun_path) -1 and error out if so?
>>
>> Great point. No reason to proceed if the filename will be truncated.
> 
> I agree, but I think we should do both, even though only one or the 
> other is needed to prevent a buffer overflow both just makes doubly 
> safe, and I tend to prefer to get rid of strcpy in favor of strncpy 
> where I see it.

This should patch both vlink.c and vlink.pl.  I still haven't tested:

--- interchange-5.12.0-rc1/dist/src/vlink.c.orig	2020-05-05 
23:09:11.408139523 +1200
+++ interchange-5.12.0-rc1/dist/src/vlink.c	2020-05-06 
05:58:00.769192141 +1200
@@ -37,6 +37,7 @@
  #include <sys/socket.h>
  #include <sys/un.h>
  #include <unistd.h>
+#include <asm-generic/errno.h>

  #ifndef ENVIRON_DECLARED
  extern char** environ;
@@ -140,12 +141,20 @@
    int i;
    int e;
    int r;
+  char *lsocket;
    uid_t euid;
    gid_t egid;

+  lsocket = getenv("MINIVEND_SOCKET");
+  if(lsocket == NULL) {
+    lsocket = LINK_FILE;
+  }
+
+  if(strlen(lsocket) > sizeof(sa.sun_path) - 1)
+    die(ENAMETOOLONG, "Socket file name too long");

    sa.sun_family = AF_UNIX;
-  strcpy(sa.sun_path, LINK_FILE);
+  strncpy(sa.sun_path, lsocket, sizeof(sa.sun_path) - 1);
  #ifdef offsetof
    size = (offsetof (struct sockaddr_un, sun_path) + strlen 
(sa.sun_path) + 1);
  #else
--- interchange-5.12.0-rc1/dist/src/vlink.pl.orig	2020-02-28 
04:07:50.000000000 +1300
+++ interchange-5.12.0-rc1/dist/src/vlink.pl	2020-05-06 
05:52:33.648898727 +1200
@@ -24,7 +24,7 @@
  require 5.014_001;
  use strict;
  use Socket;
-my $LINK_FILE    = '~@~INSTALLARCHLIB~@~/etc/socket';
+my $LINK_FILE    = $ENV{MINIVEND_SOCKET} || 
'~@~INSTALLARCHLIB~@~/etc/socket';
  #my $LINK_FILE    = '~_~LINK_FILE~_~';
  my $LINK_TIMEOUT = 30;
  #my $LINK_TIMEOUT = ~_~LINK_TIMEOUT~_~;


Peter