amd64/158369: ioctl SIOCGIFCONF in chroot bug?

[Paul Procacci]

>Number:         158369
>Category:       amd64
>Synopsis:       ioctl SIOCGIFCONF in chroot bug?
>Confidential:   no
>Severity:       critical
>Priority:       low
>Responsible:    freebsd-amd64
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Tue Jun 28 03:30:16 UTC 2011
>Closed-Date:
>Last-Modified:
>Originator:     Paul Procacci
>Release:        8.2-STABLE
>Organization:
>Environment:
FreeBSD work_machine.myhome 8.2-STABLE FreeBSD 8.2-STABLE #1: Mon Jun 27 18:51:19 CDT 2011     root at work_machine.myhome:/usr/obj/usr/src/sys/WORK_MACHINE  amd64
>Description:
chroot'd applications within a i386 environment (amd64 host) that utilize:

################################
ioctl(fd, SIOCGIFCONF, ifc); 
################################

...aren't working properly.  It's seems the ifc_len member of the ifconf structure never gets updated.

Utilizing fresh installs of both amd64 and i386 everything seems to work fine.  However when running this with a chroot'd i386 install on a amd64 host, it fails miserably.

This came up with trying to get wine working with a game.  Here is a reference to the related wine bug that I filed:

http://bugs.winehq.org/show_bug.cgi?id=27614

Thoughts?
>How-To-Repeat:
1) Install FreeBSD (I choose to install 8.2-STABLE)

2) Install an i386 chroot:
cd /usr/src && make buildworld installworld distribution TARGET=i386 DESTDIR=/compat/i386

3) Compile the following program once in the 64bit env, and again in the chroot'd 32bit env.

################################
#include <stdarg.h>
#include <stdlib.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/param.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <net/if.h>

int main(void)
{
    struct ifconf *ifc;
    struct ifconf difc;
    int lastlen, cnt = 0;
    int ioctlRet = 0;
    int guessedNumAddresses = 0, numAddresses = 0;

  int fd;
  fd = socket(PF_INET, SOCK_DGRAM, 0);

    ifc=&difc;

    ifc->ifc_len = 0;
    ifc->ifc_buf = NULL;
    if (fd != -1)
    {
        do {
          ifc->ifc_buf = NULL;
          printf("%i ::",cnt);
          cnt++;
          lastlen = ifc->ifc_len;
          if (guessedNumAddresses == 0)
            guessedNumAddresses = 4;
          else
            guessedNumAddresses *= 2;
          ifc->ifc_len = sizeof(struct ifreq) * guessedNumAddresses;
          ifc->ifc_buf = malloc(ifc->ifc_len);
          ioctlRet = ioctl(fd, SIOCGIFCONF, ifc);
          printf("  %i %i %i %s\n",ioctlRet,ifc->ifc_len,lastlen,ifc->ifc_buf);
        } while ((ioctlRet == 0) && (ifc->ifc_len != lastlen));
    }
}
################################
>Fix:
Unknown

>Release-Note:
>Audit-Trail:
>Unformatted: