| 1 |
/*
|
| 2 |
* Path sandbox for the gentoo linux portage package system, initially
|
| 3 |
* based on the ROCK Linux Wrapper for getting a list of created files
|
| 4 |
*
|
| 5 |
* to integrate with bash, bash should have been built like this
|
| 6 |
*
|
| 7 |
* ./configure --prefix=<prefix> --host=<host> --without-gnu-malloc
|
| 8 |
*
|
| 9 |
* it's very important that the --enable-static-link option is NOT specified
|
| 10 |
*
|
| 11 |
* Copyright (C) 2001 Geert Bevin, Uwyn, http://www.uwyn.com
|
| 12 |
* Distributed under the terms of the GNU General Public License, v2 or later
|
| 13 |
* Author : Geert Bevin <gbevin@uwyn.com>
|
| 14 |
*
|
| 15 |
* Post Bevin leaving Gentoo ranks:
|
| 16 |
* --------------------------------
|
| 17 |
* Ripped out all the wrappers, and implemented those of InstallWatch.
|
| 18 |
* Losts of cleanups and bugfixes. Implement a execve that forces $LIBSANDBOX
|
| 19 |
* in $LD_PRELOAD. Reformat the whole thing to look somewhat like the reworked
|
| 20 |
* sandbox.c from Brad House <brad@mainstreetsoftworks.com>.
|
| 21 |
*
|
| 22 |
* Martin Schlemmer <azarah@gentoo.org> (18 Aug 2002)
|
| 23 |
*
|
| 24 |
* Partly Copyright (C) 1998-9 Pancrazio `Ezio' de Mauro <p@demauro.net>,
|
| 25 |
* as some of the InstallWatch code was used.
|
| 26 |
*
|
| 27 |
*
|
| 28 |
* $Header$
|
| 29 |
*
|
| 30 |
*/
|
| 31 |
|
| 32 |
/* Uncomment below to enable wrapping of mknod().
|
| 33 |
* This is broken currently. */
|
| 34 |
/* #define WRAP_MKNOD 1 */
|
| 35 |
|
| 36 |
/* Uncomment below to enable the use of strtok_r(). */
|
| 37 |
#define REENTRANT_STRTOK 1
|
| 38 |
|
| 39 |
/* Uncomment below to enable memory debugging. */
|
| 40 |
/* #define SB_MEM_DEBUG 1 */
|
| 41 |
|
| 42 |
#define open xxx_open
|
| 43 |
#define open64 xxx_open64
|
| 44 |
|
| 45 |
/* Wrapping mknod, do not have any effect, and
|
| 46 |
* wrapping __xmknod causes calls to it to segfault
|
| 47 |
*/
|
| 48 |
#ifdef WRAP_MKNOD
|
| 49 |
# define __xmknod xxx___xmknod
|
| 50 |
#endif
|
| 51 |
|
| 52 |
#include <dirent.h>
|
| 53 |
#include <dlfcn.h>
|
| 54 |
#include <errno.h>
|
| 55 |
#include <fcntl.h>
|
| 56 |
#include <libgen.h>
|
| 57 |
#include <stdarg.h>
|
| 58 |
#include <stdio.h>
|
| 59 |
#include <stdlib.h>
|
| 60 |
#include <string.h>
|
| 61 |
#include <sys/file.h>
|
| 62 |
#include <sys/stat.h>
|
| 63 |
#include <sys/types.h>
|
| 64 |
#include <sys/param.h>
|
| 65 |
#include <unistd.h>
|
| 66 |
#include <utime.h>
|
| 67 |
#include "config.h"
|
| 68 |
#include "localdecls.h"
|
| 69 |
#include "symbols.h"
|
| 70 |
|
| 71 |
#ifdef SB_MEM_DEBUG
|
| 72 |
# include <mcheck.h>
|
| 73 |
#endif
|
| 74 |
|
| 75 |
#ifdef WRAP_MKNOD
|
| 76 |
# undef __xmknod
|
| 77 |
#endif
|
| 78 |
|
| 79 |
#undef open
|
| 80 |
#undef open64
|
| 81 |
|
| 82 |
//#include "localdecls.h"
|
| 83 |
#include "sandbox.h"
|
| 84 |
|
| 85 |
/* Macros to check if a function should be executed */
|
| 86 |
#define FUNCTION_SANDBOX_SAFE(func, path) \
|
| 87 |
((0 == is_sandbox_on()) || (1 == before_syscall(func, path)))
|
| 88 |
|
| 89 |
#define FUNCTION_SANDBOX_SAFE_ACCESS(func, path, flags) \
|
| 90 |
((0 == is_sandbox_on()) || (1 == before_syscall_access(func, path, flags)))
|
| 91 |
|
| 92 |
#define FUNCTION_SANDBOX_SAFE_OPEN_INT(func, path, flags) \
|
| 93 |
((0 == is_sandbox_on()) || (1 == before_syscall_open_int(func, path, flags)))
|
| 94 |
|
| 95 |
#define FUNCTION_SANDBOX_SAFE_OPEN_CHAR(func, path, mode) \
|
| 96 |
((0 == is_sandbox_on()) || (1 == before_syscall_open_char(func, path, mode)))
|
| 97 |
|
| 98 |
/* Macro to check if a wrapper is defined, if not
|
| 99 |
* then try to resolve it again. */
|
| 100 |
#define check_dlsym(name) \
|
| 101 |
{ \
|
| 102 |
int old_errno=errno; \
|
| 103 |
if (!true_ ## name) \
|
| 104 |
true_ ## name = get_dlsym(symname_ ## name, symver_ ## name); \
|
| 105 |
errno=old_errno; \
|
| 106 |
}
|
| 107 |
|
| 108 |
static char sandbox_lib[SB_PATH_MAX];
|
| 109 |
|
| 110 |
typedef struct {
|
| 111 |
int show_access_violation;
|
| 112 |
char **deny_prefixes;
|
| 113 |
int num_deny_prefixes;
|
| 114 |
char **read_prefixes;
|
| 115 |
int num_read_prefixes;
|
| 116 |
char **write_prefixes;
|
| 117 |
int num_write_prefixes;
|
| 118 |
char **predict_prefixes;
|
| 119 |
int num_predict_prefixes;
|
| 120 |
char **write_denied_prefixes;
|
| 121 |
int num_write_denied_prefixes;
|
| 122 |
} sbcontext_t;
|
| 123 |
|
| 124 |
static sbcontext_t sbcontext;
|
| 125 |
static char **cached_env_vars;
|
| 126 |
static int sb_init = 0;
|
| 127 |
static int sb_path_size_warning = 0;
|
| 128 |
|
| 129 |
void __attribute__ ((constructor)) libsb_init(void);
|
| 130 |
void __attribute__ ((destructor)) libsb_fini(void);
|
| 131 |
|
| 132 |
/* glibc modified realpath() functions */
|
| 133 |
static char *erealpath(const char *, char *);
|
| 134 |
/* glibc modified getcwd() functions */
|
| 135 |
static char *egetcwd(char *, size_t);
|
| 136 |
|
| 137 |
static void init_wrappers(void);
|
| 138 |
static void *get_dlsym(const char *, const char *);
|
| 139 |
static int canonicalize(const char *, char *);
|
| 140 |
static char *filter_path(const char *, int);
|
| 141 |
static int check_prefixes(char **, int, const char *);
|
| 142 |
static int check_access(sbcontext_t *, const char *, const char *, const char *);
|
| 143 |
static int check_syscall(sbcontext_t *, const char *, const char *);
|
| 144 |
static int before_syscall(const char *, const char *);
|
| 145 |
static int before_syscall_access(const char *, const char *, int);
|
| 146 |
static int before_syscall_open_int(const char *, const char *, int);
|
| 147 |
static int before_syscall_open_char(const char *, const char *, const char *);
|
| 148 |
static void clean_env_entries(char ***, int *);
|
| 149 |
static void init_context(sbcontext_t *);
|
| 150 |
static void init_env_entries(char ***, int *, const char *, const char *, int);
|
| 151 |
static int is_sandbox_on();
|
| 152 |
|
| 153 |
/* Wrapped functions */
|
| 154 |
|
| 155 |
extern int chmod(const char *, mode_t);
|
| 156 |
static int (*true_chmod) (const char *, mode_t) = NULL;
|
| 157 |
extern int chown(const char *, uid_t, gid_t);
|
| 158 |
static int (*true_chown) (const char *, uid_t, gid_t) = NULL;
|
| 159 |
extern int creat(const char *, mode_t);
|
| 160 |
static int (*true_creat) (const char *, mode_t) = NULL;
|
| 161 |
extern FILE *fopen(const char *, const char *);
|
| 162 |
static FILE *(*true_fopen) (const char *, const char *) = NULL;
|
| 163 |
extern int lchown(const char *, uid_t, gid_t);
|
| 164 |
static int (*true_lchown) (const char *, uid_t, gid_t) = NULL;
|
| 165 |
extern int link(const char *, const char *);
|
| 166 |
static int (*true_link) (const char *, const char *) = NULL;
|
| 167 |
extern int mkdir(const char *, mode_t);
|
| 168 |
static int (*true_mkdir) (const char *, mode_t) = NULL;
|
| 169 |
extern DIR *opendir(const char *);
|
| 170 |
static DIR *(*true_opendir) (const char *) = NULL;
|
| 171 |
#ifdef WRAP_MKNOD
|
| 172 |
extern int __xmknod(const char *, mode_t, dev_t);
|
| 173 |
static int (*true___xmknod) (const char *, mode_t, dev_t) = NULL;
|
| 174 |
#endif
|
| 175 |
extern int access(const char *, int);
|
| 176 |
static int (*true_access) (const char *, int) = NULL;
|
| 177 |
extern int open(const char *, int, ...);
|
| 178 |
static int (*true_open) (const char *, int, ...) = NULL;
|
| 179 |
extern int rename(const char *, const char *);
|
| 180 |
static int (*true_rename) (const char *, const char *) = NULL;
|
| 181 |
extern int rmdir(const char *);
|
| 182 |
static int (*true_rmdir) (const char *) = NULL;
|
| 183 |
extern int symlink(const char *, const char *);
|
| 184 |
static int (*true_symlink) (const char *, const char *) = NULL;
|
| 185 |
extern int truncate(const char *, TRUNCATE_T);
|
| 186 |
static int (*true_truncate) (const char *, TRUNCATE_T) = NULL;
|
| 187 |
extern int unlink(const char *);
|
| 188 |
static int (*true_unlink) (const char *) = NULL;
|
| 189 |
|
| 190 |
#if (GLIBC_MINOR >= 1)
|
| 191 |
|
| 192 |
extern int creat64(const char *, __mode_t);
|
| 193 |
static int (*true_creat64) (const char *, __mode_t) = NULL;
|
| 194 |
extern FILE *fopen64(const char *, const char *);
|
| 195 |
static FILE *(*true_fopen64) (const char *, const char *) = NULL;
|
| 196 |
extern int open64(const char *, int, ...);
|
| 197 |
static int (*true_open64) (const char *, int, ...) = NULL;
|
| 198 |
extern int truncate64(const char *, __off64_t);
|
| 199 |
static int (*true_truncate64) (const char *, __off64_t) = NULL;
|
| 200 |
|
| 201 |
#endif
|
| 202 |
|
| 203 |
extern int execve(const char *filename, char *const argv[], char *const envp[]);
|
| 204 |
static int (*true_execve) (const char *, char *const[], char *const[]);
|
| 205 |
|
| 206 |
/*
|
| 207 |
* Initialize the shabang
|
| 208 |
*/
|
| 209 |
|
| 210 |
static void init_wrappers(void)
|
| 211 |
{
|
| 212 |
check_dlsym(chmod);
|
| 213 |
check_dlsym(chown);
|
| 214 |
check_dlsym(creat);
|
| 215 |
check_dlsym(fopen);
|
| 216 |
check_dlsym(lchown);
|
| 217 |
check_dlsym(link);
|
| 218 |
check_dlsym(mkdir);
|
| 219 |
check_dlsym(opendir);
|
| 220 |
#ifdef WRAP_MKNOD
|
| 221 |
check_dlsym(__xmknod);
|
| 222 |
#endif
|
| 223 |
check_dlsym(access);
|
| 224 |
check_dlsym(open);
|
| 225 |
check_dlsym(rename);
|
| 226 |
check_dlsym(rmdir);
|
| 227 |
check_dlsym(symlink);
|
| 228 |
check_dlsym(truncate);
|
| 229 |
check_dlsym(unlink);
|
| 230 |
|
| 231 |
#if (GLIBC_MINOR >= 1)
|
| 232 |
check_dlsym(creat64);
|
| 233 |
check_dlsym(fopen64);
|
| 234 |
check_dlsym(open64);
|
| 235 |
check_dlsym(truncate64);
|
| 236 |
#endif
|
| 237 |
|
| 238 |
check_dlsym(execve);
|
| 239 |
}
|
| 240 |
|
| 241 |
static void *libc_handle = NULL;
|
| 242 |
|
| 243 |
static void *get_dlsym(const char *symname, const char *symver)
|
| 244 |
{
|
| 245 |
void *symaddr = NULL;
|
| 246 |
|
| 247 |
if (NULL == libc_handle) {
|
| 248 |
#ifdef BROKEN_RTLD_NEXT
|
| 249 |
libc_handle = dlopen(LIBC_VERSION, RTLD_LAZY);
|
| 250 |
if (!libc_handle) {
|
| 251 |
fprintf(stderr, "libsandbox: Can't dlopen libc: %s\n",
|
| 252 |
dlerror());
|
| 253 |
exit(EXIT_FAILURE);
|
| 254 |
}
|
| 255 |
#else
|
| 256 |
libc_handle = RTLD_NEXT;
|
| 257 |
#endif
|
| 258 |
}
|
| 259 |
|
| 260 |
if (NULL == symver)
|
| 261 |
symaddr = dlsym(libc_handle, symname);
|
| 262 |
else
|
| 263 |
symaddr = dlvsym(libc_handle, symname, symver);
|
| 264 |
if (!symaddr) {
|
| 265 |
fprintf(stderr, "libsandbox: Can't resolve %s: %s\n",
|
| 266 |
symname, dlerror());
|
| 267 |
exit(EXIT_FAILURE);
|
| 268 |
}
|
| 269 |
|
| 270 |
return symaddr;
|
| 271 |
}
|
| 272 |
|
| 273 |
|
| 274 |
void __attribute__ ((destructor)) libsb_fini(void)
|
| 275 |
{
|
| 276 |
int x;
|
| 277 |
if(NULL != cached_env_vars) {
|
| 278 |
for(x=0; x < 4; x++) {
|
| 279 |
if(NULL != cached_env_vars[x])
|
| 280 |
free(cached_env_vars[x]);
|
| 281 |
}
|
| 282 |
free(cached_env_vars);
|
| 283 |
}
|
| 284 |
clean_env_entries(&(sbcontext.deny_prefixes),
|
| 285 |
&(sbcontext.num_deny_prefixes));
|
| 286 |
clean_env_entries(&(sbcontext.read_prefixes),
|
| 287 |
&(sbcontext.num_read_prefixes));
|
| 288 |
clean_env_entries(&(sbcontext.write_prefixes),
|
| 289 |
&(sbcontext.num_write_prefixes));
|
| 290 |
clean_env_entries(&(sbcontext.predict_prefixes),
|
| 291 |
&(sbcontext.num_predict_prefixes));
|
| 292 |
}
|
| 293 |
|
| 294 |
void __attribute__ ((constructor)) libsb_init(void)
|
| 295 |
{
|
| 296 |
int old_errno = errno;
|
| 297 |
|
| 298 |
#ifdef SB_MEM_DEBUG
|
| 299 |
mtrace();
|
| 300 |
#endif
|
| 301 |
|
| 302 |
init_wrappers();
|
| 303 |
|
| 304 |
/* Get the path and name to this library */
|
| 305 |
get_sandbox_lib(sandbox_lib);
|
| 306 |
|
| 307 |
// sb_init = 1;
|
| 308 |
|
| 309 |
errno = old_errno;
|
| 310 |
}
|
| 311 |
|
| 312 |
static int canonicalize(const char *path, char *resolved_path)
|
| 313 |
{
|
| 314 |
int old_errno = errno;
|
| 315 |
char *retval;
|
| 316 |
|
| 317 |
*resolved_path = '\0';
|
| 318 |
|
| 319 |
/* If path == NULL, return or we get a segfault */
|
| 320 |
if (NULL == path) {
|
| 321 |
errno = EINVAL;
|
| 322 |
return -1;
|
| 323 |
}
|
| 324 |
|
| 325 |
/* Do not try to resolve an empty path */
|
| 326 |
if ('\0' == path[0]) {
|
| 327 |
errno = old_errno;
|
| 328 |
return 0;
|
| 329 |
}
|
| 330 |
|
| 331 |
retval = erealpath(path, resolved_path);
|
| 332 |
|
| 333 |
if ((NULL == retval) && (path[0] != '/')) {
|
| 334 |
/* The path could not be canonicalized, append it
|
| 335 |
* to the current working directory if it was not
|
| 336 |
* an absolute path
|
| 337 |
*/
|
| 338 |
|
| 339 |
if (ENAMETOOLONG == errno)
|
| 340 |
return -1;
|
| 341 |
|
| 342 |
if (NULL == egetcwd(resolved_path, SB_PATH_MAX - 2))
|
| 343 |
return -1;
|
| 344 |
snprintf((char *)(resolved_path + strlen(resolved_path)),
|
| 345 |
SB_PATH_MAX - strlen(resolved_path), "/%s", path);
|
| 346 |
|
| 347 |
if (NULL == erealpath(resolved_path, resolved_path)) {
|
| 348 |
if (errno == ENAMETOOLONG) {
|
| 349 |
/* The resolved path is too long for the buffer to hold */
|
| 350 |
return -1;
|
| 351 |
} else {
|
| 352 |
/* Whatever it resolved, is not a valid path */
|
| 353 |
errno = ENOENT;
|
| 354 |
return -1;
|
| 355 |
}
|
| 356 |
}
|
| 357 |
|
| 358 |
} else if ((NULL == retval) && (path[0] == '/')) {
|
| 359 |
/* Whatever it resolved, is not a valid path */
|
| 360 |
errno = ENOENT;
|
| 361 |
return -1;
|
| 362 |
}
|
| 363 |
|
| 364 |
errno = old_errno;
|
| 365 |
return 0;
|
| 366 |
}
|
| 367 |
|
| 368 |
static char *filter_path(const char *path, int follow_link)
|
| 369 |
{
|
| 370 |
int old_errno = errno;
|
| 371 |
char tmp_str1[SB_PATH_MAX], tmp_str2[SB_PATH_MAX];
|
| 372 |
char *dname, *bname;
|
| 373 |
char *filtered_path;
|
| 374 |
|
| 375 |
if (NULL == path)
|
| 376 |
return NULL;
|
| 377 |
|
| 378 |
filtered_path = malloc(SB_PATH_MAX * sizeof(char));
|
| 379 |
if (NULL == filtered_path)
|
| 380 |
return NULL;
|
| 381 |
|
| 382 |
if (0 == follow_link) {
|
| 383 |
if (-1 == canonicalize(path, filtered_path))
|
| 384 |
return NULL;
|
| 385 |
} else {
|
| 386 |
/* Basically we get the realpath which should resolve symlinks,
|
| 387 |
* etc. If that fails (might not exist), we try to get the
|
| 388 |
* realpath of the parent directory, as that should hopefully
|
| 389 |
* exist. If all else fails, just go with canonicalize */
|
| 390 |
if (NULL == realpath(path, filtered_path)) {
|
| 391 |
snprintf(tmp_str1, SB_PATH_MAX, "%s", path);
|
| 392 |
|
| 393 |
dname = dirname(tmp_str1);
|
| 394 |
|
| 395 |
/* If not, then check if we can resolve the
|
| 396 |
* parent directory */
|
| 397 |
if (NULL == realpath(dname, filtered_path)) {
|
| 398 |
/* Fall back to canonicalize */
|
| 399 |
if (-1 == canonicalize(path, filtered_path))
|
| 400 |
return NULL;
|
| 401 |
} else {
|
| 402 |
/* OK, now add the basename to keep our access
|
| 403 |
* checking happy (don't want '/usr/lib' if we
|
| 404 |
* tried to do something with non-existing
|
| 405 |
* file '/usr/lib/cf*' ...) */
|
| 406 |
snprintf(tmp_str2, SB_PATH_MAX, "%s", path);
|
| 407 |
|
| 408 |
bname = basename(tmp_str2);
|
| 409 |
snprintf((char *)(filtered_path + strlen(filtered_path)),
|
| 410 |
SB_PATH_MAX - strlen(filtered_path), "%s%s",
|
| 411 |
(filtered_path[strlen(filtered_path) - 1] != '/') ? "/" : "",
|
| 412 |
bname);
|
| 413 |
}
|
| 414 |
}
|
| 415 |
}
|
| 416 |
|
| 417 |
errno = old_errno;
|
| 418 |
|
| 419 |
return filtered_path;
|
| 420 |
}
|
| 421 |
|
| 422 |
/*
|
| 423 |
* Wrapper Functions
|
| 424 |
*/
|
| 425 |
|
| 426 |
int chmod(const char *path, mode_t mode)
|
| 427 |
{
|
| 428 |
int result = -1;
|
| 429 |
|
| 430 |
if FUNCTION_SANDBOX_SAFE("chmod", path) {
|
| 431 |
check_dlsym(chmod);
|
| 432 |
result = true_chmod(path, mode);
|
| 433 |
}
|
| 434 |
|
| 435 |
return result;
|
| 436 |
}
|
| 437 |
|
| 438 |
int chown(const char *path, uid_t owner, gid_t group)
|
| 439 |
{
|
| 440 |
int result = -1;
|
| 441 |
|
| 442 |
if FUNCTION_SANDBOX_SAFE("chown", path) {
|
| 443 |
check_dlsym(chown);
|
| 444 |
result = true_chown(path, owner, group);
|
| 445 |
}
|
| 446 |
|
| 447 |
return result;
|
| 448 |
}
|
| 449 |
|
| 450 |
int creat(const char *pathname, mode_t mode)
|
| 451 |
{
|
| 452 |
/* Is it a system call? */
|
| 453 |
int result = -1;
|
| 454 |
|
| 455 |
if FUNCTION_SANDBOX_SAFE("creat", pathname) {
|
| 456 |
check_dlsym(open);
|
| 457 |
result = true_open(pathname, O_CREAT | O_WRONLY | O_TRUNC, mode);
|
| 458 |
}
|
| 459 |
|
| 460 |
return result;
|
| 461 |
}
|
| 462 |
|
| 463 |
FILE *fopen(const char *pathname, const char *mode)
|
| 464 |
{
|
| 465 |
FILE *result = NULL;
|
| 466 |
|
| 467 |
if FUNCTION_SANDBOX_SAFE_OPEN_CHAR("fopen", pathname, mode) {
|
| 468 |
check_dlsym(fopen);
|
| 469 |
result = true_fopen(pathname, mode);
|
| 470 |
}
|
| 471 |
|
| 472 |
return result;
|
| 473 |
}
|
| 474 |
|
| 475 |
int lchown(const char *path, uid_t owner, gid_t group)
|
| 476 |
{
|
| 477 |
int result = -1;
|
| 478 |
|
| 479 |
if FUNCTION_SANDBOX_SAFE("lchown", path) {
|
| 480 |
check_dlsym(lchown);
|
| 481 |
result = true_lchown(path, owner, group);
|
| 482 |
}
|
| 483 |
|
| 484 |
return result;
|
| 485 |
}
|
| 486 |
|
| 487 |
int link(const char *oldpath, const char *newpath)
|
| 488 |
{
|
| 489 |
int result = -1;
|
| 490 |
|
| 491 |
if FUNCTION_SANDBOX_SAFE("link", newpath) {
|
| 492 |
check_dlsym(link);
|
| 493 |
result = true_link(oldpath, newpath);
|
| 494 |
}
|
| 495 |
|
| 496 |
return result;
|
| 497 |
}
|
| 498 |
|
| 499 |
int mkdir(const char *pathname, mode_t mode)
|
| 500 |
{
|
| 501 |
struct stat st;
|
| 502 |
int result = -1, my_errno = errno;
|
| 503 |
char canonic[SB_PATH_MAX];
|
| 504 |
|
| 505 |
if (-1 == canonicalize(pathname, canonic))
|
| 506 |
/* Path is too long to canonicalize, do not fail, but just let
|
| 507 |
* the real function handle it (see bug #94630 and #21766). */
|
| 508 |
if (ENAMETOOLONG != errno)
|
| 509 |
return -1;
|
| 510 |
|
| 511 |
/* XXX: Hack to prevent errors if the directory exist,
|
| 512 |
* and are not writable - we rather return EEXIST rather
|
| 513 |
* than failing */
|
| 514 |
if (0 == lstat(canonic, &st)) {
|
| 515 |
errno = EEXIST;
|
| 516 |
return -1;
|
| 517 |
}
|
| 518 |
errno = my_errno;
|
| 519 |
|
| 520 |
if FUNCTION_SANDBOX_SAFE("mkdir", pathname) {
|
| 521 |
check_dlsym(mkdir);
|
| 522 |
result = true_mkdir(pathname, mode);
|
| 523 |
}
|
| 524 |
|
| 525 |
return result;
|
| 526 |
}
|
| 527 |
|
| 528 |
DIR *opendir(const char *name)
|
| 529 |
{
|
| 530 |
DIR *result = NULL;
|
| 531 |
|
| 532 |
if FUNCTION_SANDBOX_SAFE("opendir", name) {
|
| 533 |
check_dlsym(opendir);
|
| 534 |
result = true_opendir(name);
|
| 535 |
}
|
| 536 |
|
| 537 |
return result;
|
| 538 |
}
|
| 539 |
|
| 540 |
#ifdef WRAP_MKNOD
|
| 541 |
|
| 542 |
int __xmknod(const char *pathname, mode_t mode, dev_t dev)
|
| 543 |
{
|
| 544 |
int result = -1;
|
| 545 |
|
| 546 |
if FUNCTION_SANDBOX_SAFE("__xmknod", pathname) {
|
| 547 |
check_dlsym(__xmknod);
|
| 548 |
result = true___xmknod(pathname, mode, dev);
|
| 549 |
}
|
| 550 |
|
| 551 |
return result;
|
| 552 |
}
|
| 553 |
|
| 554 |
#endif
|
| 555 |
|
| 556 |
int access(const char *pathname, int mode)
|
| 557 |
{
|
| 558 |
int result = -1;
|
| 559 |
|
| 560 |
if FUNCTION_SANDBOX_SAFE_ACCESS("access", pathname, mode) {
|
| 561 |
check_dlsym(access);
|
| 562 |
result = true_access(pathname, mode);
|
| 563 |
}
|
| 564 |
|
| 565 |
return result;
|
| 566 |
}
|
| 567 |
|
| 568 |
/* Eventually, there is a third parameter: it's mode_t mode */
|
| 569 |
int open(const char *pathname, int flags, ...)
|
| 570 |
{
|
| 571 |
va_list ap;
|
| 572 |
mode_t mode = 0;
|
| 573 |
int result = -1;
|
| 574 |
|
| 575 |
if (flags & O_CREAT) {
|
| 576 |
va_start(ap, flags);
|
| 577 |
mode = va_arg(ap, mode_t);
|
| 578 |
va_end(ap);
|
| 579 |
}
|
| 580 |
|
| 581 |
if FUNCTION_SANDBOX_SAFE_OPEN_INT("open", pathname, flags) {
|
| 582 |
check_dlsym(open);
|
| 583 |
result = true_open(pathname, flags, mode);
|
| 584 |
}
|
| 585 |
|
| 586 |
return result;
|
| 587 |
}
|
| 588 |
|
| 589 |
int rename(const char *oldpath, const char *newpath)
|
| 590 |
{
|
| 591 |
int result = -1;
|
| 592 |
|
| 593 |
if (FUNCTION_SANDBOX_SAFE("rename", oldpath) &&
|
| 594 |
FUNCTION_SANDBOX_SAFE("rename", newpath)) {
|
| 595 |
check_dlsym(rename);
|
| 596 |
result = true_rename(oldpath, newpath);
|
| 597 |
}
|
| 598 |
|
| 599 |
return result;
|
| 600 |
}
|
| 601 |
|
| 602 |
int rmdir(const char *pathname)
|
| 603 |
{
|
| 604 |
int result = -1;
|
| 605 |
|
| 606 |
if FUNCTION_SANDBOX_SAFE("rmdir", pathname) {
|
| 607 |
check_dlsym(rmdir);
|
| 608 |
result = true_rmdir(pathname);
|
| 609 |
}
|
| 610 |
|
| 611 |
return result;
|
| 612 |
}
|
| 613 |
|
| 614 |
int symlink(const char *oldpath, const char *newpath)
|
| 615 |
{
|
| 616 |
int result = -1;
|
| 617 |
|
| 618 |
if FUNCTION_SANDBOX_SAFE("symlink", newpath) {
|
| 619 |
check_dlsym(symlink);
|
| 620 |
result = true_symlink(oldpath, newpath);
|
| 621 |
}
|
| 622 |
|
| 623 |
return result;
|
| 624 |
}
|
| 625 |
|
| 626 |
int truncate(const char *path, TRUNCATE_T length)
|
| 627 |
{
|
| 628 |
int result = -1;
|
| 629 |
|
| 630 |
if FUNCTION_SANDBOX_SAFE("truncate", path) {
|
| 631 |
check_dlsym(truncate);
|
| 632 |
result = true_truncate(path, length);
|
| 633 |
}
|
| 634 |
|
| 635 |
return result;
|
| 636 |
}
|
| 637 |
|
| 638 |
int unlink(const char *pathname)
|
| 639 |
{
|
| 640 |
int result = -1;
|
| 641 |
char canonic[SB_PATH_MAX];
|
| 642 |
|
| 643 |
if (-1 == canonicalize(pathname, canonic))
|
| 644 |
/* Path is too long to canonicalize, do not fail, but just let
|
| 645 |
* the real function handle it (see bug #94630 and #21766). */
|
| 646 |
if (ENAMETOOLONG != errno)
|
| 647 |
return -1;
|
| 648 |
|
| 649 |
/* XXX: Hack to make sure sandboxed process cannot remove
|
| 650 |
* a device node, bug #79836. */
|
| 651 |
if ((0 == strncmp(canonic, "/dev/null", 9)) ||
|
| 652 |
(0 == strncmp(canonic, "/dev/zero", 9))) {
|
| 653 |
errno = EACCES;
|
| 654 |
return result;
|
| 655 |
}
|
| 656 |
|
| 657 |
if FUNCTION_SANDBOX_SAFE("unlink", pathname) {
|
| 658 |
check_dlsym(unlink);
|
| 659 |
result = true_unlink(pathname);
|
| 660 |
}
|
| 661 |
|
| 662 |
return result;
|
| 663 |
}
|
| 664 |
|
| 665 |
#if (GLIBC_MINOR >= 1)
|
| 666 |
|
| 667 |
int creat64(const char *pathname, __mode_t mode)
|
| 668 |
{
|
| 669 |
/* Is it a system call? */
|
| 670 |
int result = -1;
|
| 671 |
|
| 672 |
if FUNCTION_SANDBOX_SAFE("creat64", pathname) {
|
| 673 |
check_dlsym(open64);
|
| 674 |
result = true_open64(pathname, O_CREAT | O_WRONLY | O_TRUNC, mode);
|
| 675 |
}
|
| 676 |
|
| 677 |
return result;
|
| 678 |
}
|
| 679 |
|
| 680 |
FILE *fopen64(const char *pathname, const char *mode)
|
| 681 |
{
|
| 682 |
FILE *result = NULL;
|
| 683 |
|
| 684 |
if FUNCTION_SANDBOX_SAFE_OPEN_CHAR("fopen64", pathname, mode) {
|
| 685 |
check_dlsym(fopen64);
|
| 686 |
result = true_fopen64(pathname, mode);
|
| 687 |
}
|
| 688 |
|
| 689 |
return result;
|
| 690 |
}
|
| 691 |
|
| 692 |
/* Eventually, there is a third parameter: it's mode_t mode */
|
| 693 |
int open64(const char *pathname, int flags, ...)
|
| 694 |
{
|
| 695 |
va_list ap;
|
| 696 |
mode_t mode = 0;
|
| 697 |
int result = -1;
|
| 698 |
|
| 699 |
if (flags & O_CREAT) {
|
| 700 |
va_start(ap, flags);
|
| 701 |
mode = va_arg(ap, mode_t);
|
| 702 |
va_end(ap);
|
| 703 |
}
|
| 704 |
|
| 705 |
if FUNCTION_SANDBOX_SAFE_OPEN_INT("open64", pathname, flags) {
|
| 706 |
check_dlsym(open64);
|
| 707 |
result = true_open64(pathname, flags, mode);
|
| 708 |
}
|
| 709 |
|
| 710 |
return result;
|
| 711 |
}
|
| 712 |
|
| 713 |
int truncate64(const char *path, __off64_t length)
|
| 714 |
{
|
| 715 |
int result = -1;
|
| 716 |
|
| 717 |
if FUNCTION_SANDBOX_SAFE("truncate64", path) {
|
| 718 |
check_dlsym(truncate64);
|
| 719 |
result = true_truncate64(path, length);
|
| 720 |
}
|
| 721 |
|
| 722 |
return result;
|
| 723 |
}
|
| 724 |
|
| 725 |
#endif /* GLIBC_MINOR >= 1 */
|
| 726 |
|
| 727 |
/*
|
| 728 |
* Exec Wrappers
|
| 729 |
*/
|
| 730 |
|
| 731 |
int execve(const char *filename, char *const argv[], char *const envp[])
|
| 732 |
{
|
| 733 |
int old_errno = errno;
|
| 734 |
int result = -1;
|
| 735 |
int count = 0;
|
| 736 |
int env_len = 0;
|
| 737 |
char **my_env = NULL;
|
| 738 |
int kill_env = 1;
|
| 739 |
/* We limit the size LD_PRELOAD can be here, but it should be enough */
|
| 740 |
char tmp_str[SB_BUF_LEN];
|
| 741 |
|
| 742 |
if FUNCTION_SANDBOX_SAFE("execve", filename) {
|
| 743 |
while (envp[count] != NULL) {
|
| 744 |
/* Check if we do not have to do anything */
|
| 745 |
if (strstr(envp[count], LD_PRELOAD_EQ) == envp[count]) {
|
| 746 |
if (NULL != strstr(envp[count], sandbox_lib)) {
|
| 747 |
my_env = (char **)envp;
|
| 748 |
kill_env = 0;
|
| 749 |
goto end_loop;
|
| 750 |
}
|
| 751 |
}
|
| 752 |
|
| 753 |
/* If LD_PRELOAD is set and sandbox_lib not in it */
|
| 754 |
if (((strstr(envp[count], LD_PRELOAD_EQ) == envp[count]) &&
|
| 755 |
(NULL == strstr(envp[count], sandbox_lib))) ||
|
| 756 |
/* Or LD_PRELOAD is not set, and this is the last loop */
|
| 757 |
((strstr(envp[count], LD_PRELOAD_EQ) != envp[count]) &&
|
| 758 |
(NULL == envp[count + 1]))) {
|
| 759 |
int i = 0;
|
| 760 |
int add_ldpreload = 0;
|
| 761 |
const int max_envp_len = strlen(envp[count]) + strlen(sandbox_lib) + 1;
|
| 762 |
|
| 763 |
/* Fail safe ... */
|
| 764 |
if (max_envp_len > SB_BUF_LEN) {
|
| 765 |
fprintf(stderr, "libsandbox: max_envp_len too big!\n");
|
| 766 |
errno = ENOMEM;
|
| 767 |
return result;
|
| 768 |
}
|
| 769 |
|
| 770 |
/* Calculate envp size */
|
| 771 |
my_env = (char **)envp;
|
| 772 |
do
|
| 773 |
env_len++;
|
| 774 |
while (NULL != *my_env++);
|
| 775 |
|
| 776 |
/* Should we add LD_PRELOAD ? */
|
| 777 |
if (strstr(envp[count], LD_PRELOAD_EQ) != envp[count])
|
| 778 |
add_ldpreload = 1;
|
| 779 |
|
| 780 |
my_env = (char **)calloc(env_len + add_ldpreload, sizeof(char *));
|
| 781 |
if (NULL == my_env) {
|
| 782 |
errno = ENOMEM;
|
| 783 |
return result;
|
| 784 |
}
|
| 785 |
/* Copy envp to my_env */
|
| 786 |
do
|
| 787 |
/* Leave a space for LD_PRELOAD if needed */
|
| 788 |
my_env[i + add_ldpreload] = envp[i];
|
| 789 |
while (NULL != envp[i++]);
|
| 790 |
|
| 791 |
/* Add 'LD_PRELOAD=' to the beginning of our new string */
|
| 792 |
snprintf(tmp_str, max_envp_len, "%s%s", LD_PRELOAD_EQ, sandbox_lib);
|
| 793 |
|
| 794 |
/* LD_PRELOAD already have variables other than sandbox_lib,
|
| 795 |
* thus we have to add sandbox_lib seperated via a whitespace. */
|
| 796 |
if (0 == add_ldpreload) {
|
| 797 |
snprintf((char *)(tmp_str + strlen(tmp_str)),
|
| 798 |
max_envp_len - strlen(tmp_str) + 1, " %s",
|
| 799 |
(char *)(envp[count] + strlen(LD_PRELOAD_EQ)));
|
| 800 |
}
|
| 801 |
|
| 802 |
/* Valid string? */
|
| 803 |
tmp_str[max_envp_len] = '\0';
|
| 804 |
|
| 805 |
/* Ok, replace my_env[count] with our version that contains
|
| 806 |
* sandbox_lib ... */
|
| 807 |
if (1 == add_ldpreload)
|
| 808 |
/* We reserved a space for LD_PRELOAD above */
|
| 809 |
my_env[0] = tmp_str;
|
| 810 |
else
|
| 811 |
my_env[count] = tmp_str;
|
| 812 |
|
| 813 |
goto end_loop;
|
| 814 |
}
|
| 815 |
count++;
|
| 816 |
}
|
| 817 |
|
| 818 |
end_loop:
|
| 819 |
errno = old_errno;
|
| 820 |
check_dlsym(execve);
|
| 821 |
result = true_execve(filename, argv, my_env);
|
| 822 |
old_errno = errno;
|
| 823 |
|
| 824 |
if (my_env && kill_env)
|
| 825 |
free(my_env);
|
| 826 |
}
|
| 827 |
|
| 828 |
errno = old_errno;
|
| 829 |
|
| 830 |
return result;
|
| 831 |
}
|
| 832 |
|
| 833 |
/*
|
| 834 |
* Internal Functions
|
| 835 |
*/
|
| 836 |
|
| 837 |
#if (GLIBC_MINOR == 1)
|
| 838 |
|
| 839 |
/* This hack is needed for glibc 2.1.1 (and others?)
|
| 840 |
* (not really needed, but good example) */
|
| 841 |
extern int fclose(FILE *);
|
| 842 |
static int (*true_fclose) (FILE *) = NULL;
|
| 843 |
int fclose(FILE * file)
|
| 844 |
{
|
| 845 |
int result = -1;
|
| 846 |
|
| 847 |
check_dlsym(fclose);
|
| 848 |
result = true_fclose(file);
|
| 849 |
|
| 850 |
return result;
|
| 851 |
}
|
| 852 |
|
| 853 |
#endif /* GLIBC_MINOR == 1 */
|
| 854 |
|
| 855 |
static void init_context(sbcontext_t * context)
|
| 856 |
{
|
| 857 |
context->show_access_violation = 1;
|
| 858 |
context->deny_prefixes = NULL;
|
| 859 |
context->num_deny_prefixes = 0;
|
| 860 |
context->read_prefixes = NULL;
|
| 861 |
context->num_read_prefixes = 0;
|
| 862 |
context->write_prefixes = NULL;
|
| 863 |
context->num_write_prefixes = 0;
|
| 864 |
context->predict_prefixes = NULL;
|
| 865 |
context->num_predict_prefixes = 0;
|
| 866 |
context->write_denied_prefixes = NULL;
|
| 867 |
context->num_write_denied_prefixes = 0;
|
| 868 |
}
|
| 869 |
|
| 870 |
static void clean_env_entries(char ***prefixes_array, int *prefixes_num)
|
| 871 |
{
|
| 872 |
int old_errno = errno;
|
| 873 |
int i = 0;
|
| 874 |
|
| 875 |
if (NULL != *prefixes_array) {
|
| 876 |
for (i = 0; i < *prefixes_num; i++) {
|
| 877 |
if (NULL != (*prefixes_array)[i]) {
|
| 878 |
free((*prefixes_array)[i]);
|
| 879 |
(*prefixes_array)[i] = NULL;
|
| 880 |
}
|
| 881 |
}
|
| 882 |
if (NULL != *prefixes_array)
|
| 883 |
free(*prefixes_array);
|
| 884 |
*prefixes_array = NULL;
|
| 885 |
*prefixes_num = 0;
|
| 886 |
}
|
| 887 |
|
| 888 |
errno = old_errno;
|
| 889 |
}
|
| 890 |
|
| 891 |
#define pfx_num (*prefixes_num)
|
| 892 |
#define pfx_array (*prefixes_array)
|
| 893 |
#define pfx_item ((*prefixes_array)[(*prefixes_num)])
|
| 894 |
|
| 895 |
static void init_env_entries(char ***prefixes_array, int *prefixes_num, const char *env, const char *prefixes_env, int warn)
|
| 896 |
{
|
| 897 |
char *token = NULL;
|
| 898 |
char *rpath = NULL;
|
| 899 |
char *buffer = NULL;
|
| 900 |
char *buffer_ptr = NULL;
|
| 901 |
int prefixes_env_length = strlen(prefixes_env);
|
| 902 |
int num_delimiters = 0;
|
| 903 |
int i = 0;
|
| 904 |
int old_errno = errno;
|
| 905 |
|
| 906 |
if (NULL == prefixes_env) {
|
| 907 |
/* Do not warn if this is in init stage, as we might get
|
| 908 |
* issues due to LD_PRELOAD already set (bug #91431). */
|
| 909 |
if (1 == sb_init)
|
| 910 |
fprintf(stderr,
|
| 911 |
"libsandbox: The '%s' env variable is not defined!\n",
|
| 912 |
env);
|
| 913 |
if(pfx_array) {
|
| 914 |
for(i = 0; i < pfx_num; i++)
|
| 915 |
free(pfx_item);
|
| 916 |
free(pfx_array);
|
| 917 |
}
|
| 918 |
pfx_num = 0;
|
| 919 |
|
| 920 |
goto done;
|
| 921 |
}
|
| 922 |
|
| 923 |
for (i = 0; i < prefixes_env_length; i++) {
|
| 924 |
if (':' == prefixes_env[i])
|
| 925 |
num_delimiters++;
|
| 926 |
}
|
| 927 |
|
| 928 |
/* num_delimiters might be 0, and we need 2 entries at least */
|
| 929 |
pfx_array = malloc(((num_delimiters * 2) + 2) * sizeof(char *));
|
| 930 |
if (NULL == pfx_array)
|
| 931 |
goto error;
|
| 932 |
buffer = strndup(prefixes_env, prefixes_env_length);
|
| 933 |
if (NULL == buffer)
|
| 934 |
goto error;
|
| 935 |
buffer_ptr = buffer;
|
| 936 |
|
| 937 |
#ifdef REENTRANT_STRTOK
|
| 938 |
token = strtok_r(buffer_ptr, ":", &buffer_ptr);
|
| 939 |
#else
|
| 940 |
token = strtok(buffer_ptr, ":");
|
| 941 |
#endif
|
| 942 |
|
| 943 |
while ((NULL != token) && (strlen(token) > 0)) {
|
| 944 |
pfx_item = filter_path(token, 0);
|
| 945 |
if (NULL != pfx_item) {
|
| 946 |
pfx_num++;
|
| 947 |
|
| 948 |
/* Now add the realpath if it exists and
|
| 949 |
* are not a duplicate */
|
| 950 |
rpath = malloc(SB_PATH_MAX * sizeof(char));
|
| 951 |
if (NULL != rpath) {
|
| 952 |
pfx_item = realpath(*(&(pfx_item) - 1), rpath);
|
| 953 |
if ((NULL != pfx_item) &&
|
| 954 |
(0 != strcmp(*(&(pfx_item) - 1), pfx_item))) {
|
| 955 |
pfx_num++;
|
| 956 |
} else {
|
| 957 |
free(rpath);
|
| 958 |
pfx_item = NULL;
|
| 959 |
}
|
| 960 |
} else {
|
| 961 |
goto error;
|
| 962 |
}
|
| 963 |
}
|
| 964 |
|
| 965 |
#ifdef REENTRANT_STRTOK
|
| 966 |
token = strtok_r(NULL, ":", &buffer_ptr);
|
| 967 |
#else
|
| 968 |
token = strtok(NULL, ":");
|
| 969 |
#endif
|
| 970 |
}
|
| 971 |
|
| 972 |
free(buffer);
|
| 973 |
|
| 974 |
done:
|
| 975 |
errno = old_errno;
|
| 976 |
return;
|
| 977 |
|
| 978 |
error:
|
| 979 |
perror("libsandbox: Could not initialize environ\n");
|
| 980 |
exit(EXIT_FAILURE);
|
| 981 |
}
|
| 982 |
|
| 983 |
static int check_prefixes(char **prefixes, int num_prefixes, const char *path)
|
| 984 |
{
|
| 985 |
int i = 0;
|
| 986 |
|
| 987 |
if (NULL == prefixes)
|
| 988 |
return 0;
|
| 989 |
|
| 990 |
for (i = 0; i < num_prefixes; i++) {
|
| 991 |
if (NULL != prefixes[i]) {
|
| 992 |
if (0 == strncmp(path, prefixes[i], strlen(prefixes[i])))
|
| 993 |
return 1;
|
| 994 |
}
|
| 995 |
}
|
| 996 |
|
| 997 |
return 0;
|
| 998 |
}
|
| 999 |
|
| 1000 |
static int check_access(sbcontext_t * sbcontext, const char *func, const char *path, const char *fpath)
|
| 1001 |
{
|
| 1002 |
int old_errno = errno;
|
| 1003 |
int result = 0;
|
| 1004 |
int retval;
|
| 1005 |
|
| 1006 |
retval = check_prefixes(sbcontext->deny_prefixes,
|
| 1007 |
sbcontext->num_deny_prefixes, fpath);
|
| 1008 |
if (1 == retval)
|
| 1009 |
/* Fall in a read/write denied path, Deny Access */
|
| 1010 |
goto out;
|
| 1011 |
|
| 1012 |
/* Hardcode denying write to log dir */
|
| 1013 |
if (0 == strncmp(fpath, SANDBOX_LOG_LOCATION,
|
| 1014 |
strlen(SANDBOX_LOG_LOCATION)))
|
| 1015 |
goto out;
|
| 1016 |
|
| 1017 |
if ((NULL != sbcontext->read_prefixes) &&
|
| 1018 |
((0 == strncmp(func, "access_rd", 9)) ||
|
| 1019 |
(0 == strncmp(func, "open_rd", 7)) ||
|
| 1020 |
(0 == strncmp(func, "popen", 5)) ||
|
| 1021 |
(0 == strncmp(func, "opendir", 7)) ||
|
| 1022 |
(0 == strncmp(func, "system", 6)) ||
|
| 1023 |
(0 == strncmp(func, "execl", 5)) ||
|
| 1024 |
(0 == strncmp(func, "execlp", 6)) ||
|
| 1025 |
(0 == strncmp(func, "execle", 6)) ||
|
| 1026 |
(0 == strncmp(func, "execv", 5)) ||
|
| 1027 |
(0 == strncmp(func, "execvp", 6)) ||
|
| 1028 |
(0 == strncmp(func, "execve", 6)))) {
|
| 1029 |
retval = check_prefixes(sbcontext->read_prefixes,
|
| 1030 |
sbcontext->num_read_prefixes, fpath);
|
| 1031 |
if (1 == retval) {
|
| 1032 |
/* Fall in a readable path, Grant Access */
|
| 1033 |
result = 1;
|
| 1034 |
goto out;
|
| 1035 |
}
|
| 1036 |
}
|
| 1037 |
|
| 1038 |
if ((0 == strncmp(func, "access_wr", 7)) ||
|
| 1039 |
(0 == strncmp(func, "open_wr", 7)) ||
|
| 1040 |
(0 == strncmp(func, "creat", 5)) ||
|
| 1041 |
(0 == strncmp(func, "creat64", 7)) ||
|
| 1042 |
(0 == strncmp(func, "mkdir", 5)) ||
|
| 1043 |
(0 == strncmp(func, "mknod", 5)) ||
|
| 1044 |
(0 == strncmp(func, "mkfifo", 6)) ||
|
| 1045 |
(0 == strncmp(func, "link", 4)) ||
|
| 1046 |
(0 == strncmp(func, "symlink", 7)) ||
|
| 1047 |
(0 == strncmp(func, "rename", 6)) ||
|
| 1048 |
(0 == strncmp(func, "utime", 5)) ||
|
| 1049 |
(0 == strncmp(func, "utimes", 6)) ||
|
| 1050 |
(0 == strncmp(func, "unlink", 6)) ||
|
| 1051 |
(0 == strncmp(func, "rmdir", 5)) ||
|
| 1052 |
(0 == strncmp(func, "chown", 5)) ||
|
| 1053 |
(0 == strncmp(func, "lchown", 6)) ||
|
| 1054 |
(0 == strncmp(func, "chmod", 5)) ||
|
| 1055 |
(0 == strncmp(func, "truncate", 8)) ||
|
| 1056 |
(0 == strncmp(func, "ftruncate", 9)) ||
|
| 1057 |
(0 == strncmp(func, "truncate64", 10)) ||
|
| 1058 |
(0 == strncmp(func, "ftruncate64", 11))) {
|
| 1059 |
struct stat st;
|
| 1060 |
char proc_self_fd[SB_PATH_MAX];
|
| 1061 |
|
| 1062 |
retval = check_prefixes(sbcontext->write_denied_prefixes,
|
| 1063 |
sbcontext->num_write_denied_prefixes,
|
| 1064 |
fpath);
|
| 1065 |
if (1 == retval)
|
| 1066 |
/* Falls in a write denied path, Deny Access */
|
| 1067 |
goto out;
|
| 1068 |
|
| 1069 |
retval = check_prefixes(sbcontext->write_prefixes,
|
| 1070 |
sbcontext->num_write_prefixes, fpath);
|
| 1071 |
if (1 == retval) {
|
| 1072 |
/* Falls in a writable path, Grant Access */
|
| 1073 |
result = 1;
|
| 1074 |
goto out;
|
| 1075 |
}
|
| 1076 |
|
| 1077 |
/* XXX: Hack to enable us to remove symlinks pointing
|
| 1078 |
* to protected stuff. First we make sure that the
|
| 1079 |
* passed path is writable, and if so, check if its a
|
| 1080 |
* symlink, and give access only if the resolved path
|
| 1081 |
* of the symlink's parent also have write access. */
|
| 1082 |
if (((0 == strncmp(func, "unlink", 6)) ||
|
| 1083 |
(0 == strncmp(func, "lchown", 6)) ||
|
| 1084 |
(0 == strncmp(func, "rename", 6))) &&
|
| 1085 |
((-1 != lstat(path, &st)) && (S_ISLNK(st.st_mode)))) {
|
| 1086 |
/* Check if the symlink unresolved path have access */
|
| 1087 |
retval = check_prefixes(sbcontext->write_prefixes,
|
| 1088 |
sbcontext->num_write_prefixes, path);
|
| 1089 |
if (1 == retval) { /* Does have write access on path */
|
| 1090 |
char tmp_buf[SB_PATH_MAX];
|
| 1091 |
char *dname, *rpath;
|
| 1092 |
|
| 1093 |
snprintf(tmp_buf, SB_PATH_MAX, "%s", path);
|
| 1094 |
|
| 1095 |
dname = dirname(tmp_buf);
|
| 1096 |
/* Get symlink resolved path */
|
| 1097 |
rpath = filter_path(dname, 1);
|
| 1098 |
if (NULL == rpath)
|
| 1099 |
/* Don't really worry here about
|
| 1100 |
* memory issues */
|
| 1101 |
goto unlink_hack_end;
|
| 1102 |
|
| 1103 |
/* Now check if the symlink resolved path have access */
|
| 1104 |
retval = check_prefixes(sbcontext->write_prefixes,
|
| 1105 |
sbcontext->num_write_prefixes,
|
| 1106 |
rpath);
|
| 1107 |
free(rpath);
|
| 1108 |
if (1 == retval) {
|
| 1109 |
/* Does have write access on path, so
|
| 1110 |
* enable the hack as it is a symlink */
|
| 1111 |
result = 1;
|
| 1112 |
goto out;
|
| 1113 |
}
|
| 1114 |
}
|
| 1115 |
}
|
| 1116 |
unlink_hack_end:
|
| 1117 |
|
| 1118 |
/* XXX: Hack to allow writing to '/proc/self/fd' (bug #91516)
|
| 1119 |
* It needs to be here, as for each process '/proc/self'
|
| 1120 |
* will differ ... */
|
| 1121 |
if ((0 == strncmp(fpath, "/proc", strlen("/proc"))) &&
|
| 1122 |
(NULL != realpath("/proc/self/fd", proc_self_fd))) {
|
| 1123 |
if (0 == strncmp(fpath, proc_self_fd,
|
| 1124 |
strlen(proc_self_fd))) {
|
| 1125 |
result = 1;
|
| 1126 |
goto out;
|
| 1127 |
}
|
| 1128 |
}
|
| 1129 |
|
| 1130 |
retval = check_prefixes(sbcontext->predict_prefixes,
|
| 1131 |
sbcontext->num_predict_prefixes, fpath);
|
| 1132 |
if (1 == retval) {
|
| 1133 |
/* Is a known access violation, so deny access,
|
| 1134 |
* and do not log it */
|
| 1135 |
sbcontext->show_access_violation = 0;
|
| 1136 |
goto out;
|
| 1137 |
}
|
| 1138 |
}
|
| 1139 |
|
| 1140 |
out:
|
| 1141 |
errno = old_errno;
|
| 1142 |
|
| 1143 |
return result;
|
| 1144 |
}
|
| 1145 |
|
| 1146 |
static int check_syscall(sbcontext_t * sbcontext, const char *func, const char *file)
|
| 1147 |
{
|
| 1148 |
struct stat log_stat;
|
| 1149 |
char buffer[512];
|
| 1150 |
char *absolute_path = NULL;
|
| 1151 |
char *resolved_path = NULL;
|
| 1152 |
char *log_path = NULL;
|
| 1153 |
int old_errno = errno;
|
| 1154 |
int result = 1;
|
| 1155 |
int log_file = 0;
|
| 1156 |
int debug = 0;
|
| 1157 |
int color = ((getenv("NOCOLOR") != NULL) ? 0 : 1);
|
| 1158 |
|
| 1159 |
init_wrappers();
|
| 1160 |
|
| 1161 |
absolute_path = filter_path(file, 0);
|
| 1162 |
if (NULL == absolute_path)
|
| 1163 |
goto fp_error;
|
| 1164 |
resolved_path = filter_path(file, 1);
|
| 1165 |
if (NULL == resolved_path)
|
| 1166 |
goto fp_error;
|
| 1167 |
|
| 1168 |
if (NULL == getenv("SANDBOX_DEBUG")) {
|
| 1169 |
log_path = getenv("SANDBOX_LOG");
|
| 1170 |
} else {
|
| 1171 |
log_path = getenv("SANDBOX_DEBUG_LOG");
|
| 1172 |
debug = 1;
|
| 1173 |
}
|
| 1174 |
|
| 1175 |
result = check_access(sbcontext, func, absolute_path, resolved_path);
|
| 1176 |
|
| 1177 |
if ((0 == result) && (1 == sbcontext->show_access_violation)) {
|
| 1178 |
EERROR(color, "ACCESS DENIED", " %s:%*s%s\n",
|
| 1179 |
func, (int)(10 - strlen(func)), "", absolute_path);
|
| 1180 |
} else if ((1 == debug) && (1 == sbcontext->show_access_violation)) {
|
| 1181 |
EINFO(color, "ACCESS ALLOWED", " %s:%*s%s\n",
|
| 1182 |
func, (int)(10 - strlen(func)), "", absolute_path);
|
| 1183 |
} else if ((1 == debug) && (0 == sbcontext->show_access_violation)) {
|
| 1184 |
EWARN(color, "ACCESS PREDICTED", " %s:%*s%s\n",
|
| 1185 |
func, (int)(10 - strlen(func)), "", absolute_path);
|
| 1186 |
}
|
| 1187 |
|
| 1188 |
if ((NULL != log_path) &&
|
| 1189 |
(((0 == debug) && (0 == result) && (1 == sbcontext->show_access_violation)) ||
|
| 1190 |
(1 == debug))) {
|
| 1191 |
if (0 != strncmp(absolute_path, resolved_path, strlen(absolute_path))) {
|
| 1192 |
sprintf(buffer, "%s:%*s%s (symlink to %s)\n", func,
|
| 1193 |
(int)(10 - strlen(func)), "",
|
| 1194 |
absolute_path, resolved_path);
|
| 1195 |
} else {
|
| 1196 |
sprintf(buffer, "%s:%*s%s\n", func,
|
| 1197 |
(int)(10 - strlen(func)), "",
|
| 1198 |
absolute_path);
|
| 1199 |
}
|
| 1200 |
if ((0 == lstat(log_path, &log_stat)) &&
|
| 1201 |
(0 == S_ISREG(log_stat.st_mode))) {
|
| 1202 |
EERROR(color, "SECURITY BREACH", " '%s' %s\n", log_path,
|
| 1203 |
"already exists and is not a regular file!");
|
| 1204 |
} else {
|
| 1205 |
check_dlsym(open);
|
| 1206 |
log_file = true_open(log_path, O_APPEND | O_WRONLY |
|
| 1207 |
O_CREAT, S_IRUSR | S_IWUSR | S_IRGRP |
|
| 1208 |
S_IROTH);
|
| 1209 |
if (log_file >= 0) {
|
| 1210 |
write(log_file, buffer, strlen(buffer));
|
| 1211 |
close(log_file);
|
| 1212 |
}
|
| 1213 |
}
|
| 1214 |
}
|
| 1215 |
|
| 1216 |
if (NULL != absolute_path)
|
| 1217 |
free(absolute_path);
|
| 1218 |
if (NULL != resolved_path)
|
| 1219 |
free(resolved_path);
|
| 1220 |
|
| 1221 |
errno = old_errno;
|
| 1222 |
|
| 1223 |
return result;
|
| 1224 |
|
| 1225 |
fp_error:
|
| 1226 |
if (NULL != absolute_path)
|
| 1227 |
free(absolute_path);
|
| 1228 |
if (NULL != resolved_path)
|
| 1229 |
free(resolved_path);
|
| 1230 |
|
| 1231 |
/* The path is too long to be canonicalized, so just warn and let the
|
| 1232 |
* function handle it (see bug #94630 and #21766 for more info) */
|
| 1233 |
if (ENAMETOOLONG == errno) {
|
| 1234 |
if (0 == sb_path_size_warning) {
|
| 1235 |
EWARN(color, "PATH LENGTH", " %s:%*s%s\n",
|
| 1236 |
func, (int)(10 - strlen(func)), "", file);
|
| 1237 |
sb_path_size_warning = 1;
|
| 1238 |
}
|
| 1239 |
|
| 1240 |
return 1;
|
| 1241 |
}
|
| 1242 |
|
| 1243 |
return 0;
|
| 1244 |
}
|
| 1245 |
|
| 1246 |
static int is_sandbox_on()
|
| 1247 |
{
|
| 1248 |
int old_errno = errno;
|
| 1249 |
|
| 1250 |
/* $SANDBOX_ACTIVE is an env variable that should ONLY
|
| 1251 |
* be used internal by sandbox.c and libsanbox.c. External
|
| 1252 |
* sources should NEVER set it, else the sandbox is enabled
|
| 1253 |
* in some cases when run in parallel with another sandbox,
|
| 1254 |
* but not even in the sandbox shell.
|
| 1255 |
*
|
| 1256 |
* Azarah (3 Aug 2002)
|
| 1257 |
*/
|
| 1258 |
if ((NULL != getenv("SANDBOX_ON")) &&
|
| 1259 |
(0 == strncmp(getenv("SANDBOX_ON"), "1", 1)) &&
|
| 1260 |
(NULL != getenv("SANDBOX_ACTIVE")) &&
|
| 1261 |
(0 == strncmp(getenv("SANDBOX_ACTIVE"), "armedandready", 13))) {
|
| 1262 |
errno = old_errno;
|
| 1263 |
return 1;
|
| 1264 |
} else {
|
| 1265 |
errno = old_errno;
|
| 1266 |
return 0;
|
| 1267 |
}
|
| 1268 |
}
|
| 1269 |
|
| 1270 |
static int before_syscall(const char *func, const char *file)
|
| 1271 |
{
|
| 1272 |
int old_errno = errno;
|
| 1273 |
int result = 1;
|
| 1274 |
// static sbcontext_t sbcontext;
|
| 1275 |
char *deny = getenv("SANDBOX_DENY");
|
| 1276 |
char *read = getenv("SANDBOX_READ");
|
| 1277 |
char *write = getenv("SANDBOX_WRITE");
|
| 1278 |
char *predict = getenv("SANDBOX_PREDICT");
|
| 1279 |
|
| 1280 |
if (NULL == file || 0 == strlen(file)) {
|
| 1281 |
/* The file/directory does not exist */
|
| 1282 |
errno = ENOENT;
|
| 1283 |
return 0;
|
| 1284 |
}
|
| 1285 |
|
| 1286 |
if(sb_init == 0) {
|
| 1287 |
init_context(&sbcontext);
|
| 1288 |
cached_env_vars = malloc(sizeof(char *)*4);
|
| 1289 |
cached_env_vars[0] = cached_env_vars[1] = cached_env_vars[2] = cached_env_vars[3] = NULL;
|
| 1290 |
sb_init=1;
|
| 1291 |
}
|
| 1292 |
|
| 1293 |
if((deny == NULL && cached_env_vars[0] != deny) || cached_env_vars[0] == NULL ||
|
| 1294 |
strcmp(cached_env_vars[0], deny) != 0) {
|
| 1295 |
|
| 1296 |
clean_env_entries(&(sbcontext.deny_prefixes),
|
| 1297 |
&(sbcontext.num_deny_prefixes));
|
| 1298 |
|
| 1299 |
if(NULL != cached_env_vars[0])
|
| 1300 |
free(cached_env_vars[0]);
|
| 1301 |
|
| 1302 |
if(NULL != deny) {
|
| 1303 |
init_env_entries(&(sbcontext.deny_prefixes),
|
| 1304 |
&(sbcontext.num_deny_prefixes), "SANDBOX_DENY", deny, 1);
|
| 1305 |
cached_env_vars[0] = strdup(deny);
|
| 1306 |
} else {
|
| 1307 |
cached_env_vars[0] = NULL;
|
| 1308 |
}
|
| 1309 |
}
|
| 1310 |
|
| 1311 |
if((read == NULL && cached_env_vars[1] != read) || cached_env_vars[1] == NULL ||
|
| 1312 |
strcmp(cached_env_vars[1], read) != 0) {
|
| 1313 |
|
| 1314 |
clean_env_entries(&(sbcontext.read_prefixes),
|
| 1315 |
&(sbcontext.num_read_prefixes));
|
| 1316 |
|
| 1317 |
if(NULL != cached_env_vars[1])
|
| 1318 |
free(cached_env_vars[1]);
|
| 1319 |
|
| 1320 |
if(NULL != read) {
|
| 1321 |
init_env_entries(&(sbcontext.read_prefixes),
|
| 1322 |
&(sbcontext.num_read_prefixes), "SANDBOX_READ", read, 1);
|
| 1323 |
cached_env_vars[1] = strdup(read);
|
| 1324 |
} else {
|
| 1325 |
cached_env_vars[1] = NULL;
|
| 1326 |
}
|
| 1327 |
}
|
| 1328 |
|
| 1329 |
if((write == NULL && cached_env_vars[2] != write) || cached_env_vars[2] == NULL ||
|
| 1330 |
strcmp(cached_env_vars[2], write) != 0) {
|
| 1331 |
|
| 1332 |
clean_env_entries(&(sbcontext.write_prefixes),
|
| 1333 |
&(sbcontext.num_write_prefixes));
|
| 1334 |
|
| 1335 |
if(NULL != cached_env_vars[2])
|
| 1336 |
free(cached_env_vars[2]);
|
| 1337 |
|
| 1338 |
if(NULL != write) {
|
| 1339 |
init_env_entries(&(sbcontext.write_prefixes),
|
| 1340 |
&(sbcontext.num_write_prefixes), "SANDBOX_WRITE", write, 1);
|
| 1341 |
cached_env_vars[2] = strdup(write);
|
| 1342 |
} else {
|
| 1343 |
cached_env_vars[2] = NULL;
|
| 1344 |
}
|
| 1345 |
}
|
| 1346 |
|
| 1347 |
if((predict == NULL && cached_env_vars[3] != predict) || cached_env_vars[3] == NULL ||
|
| 1348 |
strcmp(cached_env_vars[3], predict) != 0) {
|
| 1349 |
|
| 1350 |
clean_env_entries(&(sbcontext.predict_prefixes),
|
| 1351 |
&(sbcontext.num_predict_prefixes));
|
| 1352 |
|
| 1353 |
if(NULL != cached_env_vars[3])
|
| 1354 |
free(cached_env_vars[3]);
|
| 1355 |
|
| 1356 |
if(NULL != predict) {
|
| 1357 |
init_env_entries(&(sbcontext.predict_prefixes),
|
| 1358 |
&(sbcontext.num_predict_prefixes), "SANDBOX_PREDICT", predict, 1);
|
| 1359 |
cached_env_vars[3] = strdup(predict);
|
| 1360 |
} else {
|
| 1361 |
cached_env_vars[3] = NULL;
|
| 1362 |
}
|
| 1363 |
|
| 1364 |
}
|
| 1365 |
|
| 1366 |
/* Might have been reset in check_access() */
|
| 1367 |
sbcontext.show_access_violation = 1;
|
| 1368 |
|
| 1369 |
result = check_syscall(&sbcontext, func, file);
|
| 1370 |
|
| 1371 |
errno = old_errno;
|
| 1372 |
|
| 1373 |
if (0 == result) {
|
| 1374 |
errno = EACCES;
|
| 1375 |
}
|
| 1376 |
|
| 1377 |
return result;
|
| 1378 |
}
|
| 1379 |
|
| 1380 |
static int before_syscall_access(const char *func, const char *file, int flags)
|
| 1381 |
{
|
| 1382 |
if (flags & W_OK) {
|
| 1383 |
return before_syscall("access_wr", file);
|
| 1384 |
} else {
|
| 1385 |
return before_syscall("access_rd", file);
|
| 1386 |
}
|
| 1387 |
}
|
| 1388 |
|
| 1389 |
static int before_syscall_open_int(const char *func, const char *file, int flags)
|
| 1390 |
{
|
| 1391 |
if ((flags & O_WRONLY) || (flags & O_RDWR)) {
|
| 1392 |
return before_syscall("open_wr", file);
|
| 1393 |
} else {
|
| 1394 |
return before_syscall("open_rd", file);
|
| 1395 |
}
|
| 1396 |
}
|
| 1397 |
|
| 1398 |
static int before_syscall_open_char(const char *func, const char *file, const char *mode)
|
| 1399 |
{
|
| 1400 |
if (*mode == 'r' && ((strcmp(mode, "r") == 0) ||
|
| 1401 |
/* The strspn accept args are known non-writable modifiers */
|
| 1402 |
(strlen(++mode) == strspn(mode, "xbtmc")))) {
|
| 1403 |
return before_syscall("open_rd", file);
|
| 1404 |
} else {
|
| 1405 |
return before_syscall("open_wr", file);
|
| 1406 |
}
|
| 1407 |
}
|
| 1408 |
|
| 1409 |
#include "getcwd.c"
|
| 1410 |
#include "canonicalize.c"
|
| 1411 |
#include "sandbox_futils.c"
|
| 1412 |
|
| 1413 |
// vim:noexpandtab noai:cindent ai
|
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