/*
* libsandbox.c
*
* Main libsandbox related functions.
*
* Copyright 1999-2008 Gentoo Foundation
* Licensed under the GPL-2
*
* Partly Copyright (C) 1998-9 Pancrazio `Ezio' de Mauro
,
* as some of the InstallWatch code was used.
*/
/* Uncomment below to enable memory debugging. */
/* #define SB_MEM_DEBUG 1 */
#define open xxx_open
#define open64 xxx_open64
#include "headers.h"
#ifdef SB_MEM_DEBUG
# include
#endif
#undef open
#undef open64
#include "sbutil.h"
#include "libsandbox.h"
#include "wrappers.h"
#include "sb_nr.h"
#define LOG_VERSION "1.0"
#define LOG_STRING "VERSION " LOG_VERSION "\n"
#define LOG_FMT_FUNC "FORMAT: F - Function called\n"
#define LOG_FMT_ACCESS "FORMAT: S - Access Status\n"
#define LOG_FMT_PATH "FORMAT: P - Path as passed to function\n"
#define LOG_FMT_APATH "FORMAT: A - Absolute Path (not canonical)\n"
#define LOG_FMT_RPATH "FORMAT: R - Canonical Path\n"
#define LOG_FMT_CMDLINE "FORMAT: C - Command Line\n"
#define PROC_DIR "/proc"
#define PROC_SELF_FD PROC_DIR "/self/fd"
#define PROC_SELF_CMDLINE PROC_DIR "/self/cmdline"
char sandbox_lib[SB_PATH_MAX];
typedef struct {
bool show_access_violation;
char **prefixes[5];
int num_prefixes[5];
#define deny_prefixes prefixes[0]
#define num_deny_prefixes num_prefixes[0]
#define read_prefixes prefixes[1]
#define num_read_prefixes num_prefixes[1]
#define write_prefixes prefixes[2]
#define num_write_prefixes num_prefixes[2]
#define predict_prefixes prefixes[3]
#define num_predict_prefixes num_prefixes[3]
#define write_denied_prefixes prefixes[4]
#define num_write_denied_prefixes num_prefixes[4]
#define MAX_DYN_PREFIXES 4 /* the first 4 are dynamic */
} sbcontext_t;
static sbcontext_t sbcontext;
static char *cached_env_vars[MAX_DYN_PREFIXES];
volatile bool sandbox_on = true;
static bool sb_init = false;
static char *resolve_path(const char *, int);
static int check_prefixes(char **, int, const char *);
static void clean_env_entries(char ***, int *);
static void init_context(sbcontext_t *);
static void init_env_entries(char ***, int *, const char *, const char *, int);
/*
* Initialize the shabang
*/
__attribute__((destructor))
void libsb_fini(void)
{
int x;
sb_init = false;
for (x = 0; x < MAX_DYN_PREFIXES; ++x) {
if (NULL != cached_env_vars[x]) {
free(cached_env_vars[x]);
cached_env_vars[x] = NULL;
}
}
for (x = 0; x < MAX_DYN_PREFIXES; ++x)
clean_env_entries(&(sbcontext.prefixes[x]),
&(sbcontext.num_prefixes[x]));
}
__attribute__((constructor))
void libsb_init(void)
{
int old_errno = errno;
#ifdef SB_MEM_DEBUG
mtrace();
#endif
sb_set_open(sb_unwrapped_open);
/* Get the path and name to this library */
get_sandbox_lib(sandbox_lib);
// sb_init = true;
errno = old_errno;
}
int canonicalize(const char *path, char *resolved_path)
{
int old_errno = errno;
char *retval;
*resolved_path = '\0';
/* If path == NULL, return or we get a segfault */
if (NULL == path) {
errno = EINVAL;
return -1;
}
/* Do not try to resolve an empty path */
if ('\0' == path[0]) {
errno = old_errno;
return 0;
}
retval = erealpath(path, resolved_path);
if ((NULL == retval) && (path[0] != '/')) {
/* The path could not be canonicalized, append it
* to the current working directory if it was not
* an absolute path
*/
if (ENAMETOOLONG == errno)
return -1;
if (NULL == egetcwd(resolved_path, SB_PATH_MAX - 2))
return -1;
size_t len = strlen(resolved_path);
snprintf(resolved_path + len, SB_PATH_MAX - len, "/%s", path);
if (NULL == erealpath(resolved_path, resolved_path)) {
if (errno == ENAMETOOLONG) {
/* The resolved path is too long for the buffer to hold */
return -1;
} else {
/* Whatever it resolved, is not a valid path */
errno = ENOENT;
return -1;
}
}
} else if ((NULL == retval) && (path[0] == '/')) {
/* Whatever it resolved, is not a valid path */
errno = ENOENT;
return -1;
}
errno = old_errno;
return 0;
}
static char *resolve_path(const char *path, int follow_link)
{
char *dname, *bname;
char *filtered_path;
if (NULL == path)
return NULL;
save_errno();
filtered_path = xmalloc(SB_PATH_MAX * sizeof(char));
if (0 == follow_link) {
if (-1 == canonicalize(path, filtered_path)) {
free(filtered_path);
filtered_path = NULL;
}
} else {
/* Basically we get the realpath which should resolve symlinks,
* etc. If that fails (might not exist), we try to get the
* realpath of the parent directory, as that should hopefully
* exist. If all else fails, just go with canonicalize */
if (NULL == realpath(path, filtered_path)) {
char tmp_str1[SB_PATH_MAX];
snprintf(tmp_str1, SB_PATH_MAX, "%s", path);
dname = dirname(tmp_str1);
/* If not, then check if we can resolve the
* parent directory */
if (NULL == realpath(dname, filtered_path)) {
/* Fall back to canonicalize */
if (-1 == canonicalize(path, filtered_path)) {
free(filtered_path);
filtered_path = NULL;
}
} else {
char tmp_str2[SB_PATH_MAX];
/* OK, now add the basename to keep our access
* checking happy (don't want '/usr/lib' if we
* tried to do something with non-existing
* file '/usr/lib/cf*' ...) */
snprintf(tmp_str2, SB_PATH_MAX, "%s", path);
bname = basename(tmp_str2);
size_t len = strlen(filtered_path);
snprintf(filtered_path + len, SB_PATH_MAX - len, "%s%s",
(filtered_path[len - 1] != '/') ? "/" : "",
bname);
}
}
}
restore_errno();
return filtered_path;
}
/*
* Internal Functions
*/
char *egetcwd(char *buf, size_t size)
{
struct stat st;
char *tmpbuf, *oldbuf = buf;
/* Need to disable sandbox, as on non-linux libc's, opendir() is
* used by some getcwd() implementations and resolves to the sandbox
* opendir() wrapper, causing infinit recursion and finially crashes.
*/
sandbox_on = false;
errno = 0;
tmpbuf = sb_unwrapped_getcwd(buf, size);
sandbox_on = true;
/* We basically try to figure out if we can trust what getcwd()
* returned. If one of the following happens kernel/libc side,
* bad things will happen, but not much we can do about it:
* - Invalid pointer with errno = 0
* - Truncated path with errno = 0
* - Whatever I forgot about
*/
if ((tmpbuf) && (errno == 0)) {
save_errno();
if (!lstat(buf, &st))
/* errno is set only on failure */
errno = 0;
if (errno == ENOENT)
/* If lstat() failed with eerror = ENOENT, then its
* possible that we are running on an older kernel
* which had issues with returning invalid paths if
* they got too long. Return with errno = ENAMETOOLONG,
* so that canonicalize() and check_syscall() know
* what the issue is.
*/
errno = ENAMETOOLONG;
if (errno) {
/* If getcwd() allocated the buffer, free it. */
if (NULL == oldbuf)
free(tmpbuf);
/* Not sure if we should quit here, but I guess if
* lstat() fails, getcwd could have messed up. Not
* sure what to do about errno - use lstat()'s for
* now.
*/
return NULL;
}
restore_errno();
} else if (errno != 0) {
/* Make sure we do not return garbage if the current libc or
* kernel's getcwd() is buggy.
*/
return NULL;
}
return tmpbuf;
}
#define _SB_WRITE_STR(str) SB_WRITE(logfd, str, strlen(str), error)
static bool write_logfile(const char *logfile, const char *func, const char *path,
const char *apath, const char *rpath, bool access)
{
struct stat log_stat;
int stat_ret;
int logfd;
stat_ret = lstat(logfile, &log_stat);
/* Do not care about failure */
errno = 0;
if ((0 == stat_ret) &&
(0 == S_ISREG(log_stat.st_mode))) {
SB_EERROR("SECURITY BREACH", " '%s' %s\n", logfile,
"already exists and is not a regular file!");
abort();
}
logfd = sb_open(logfile,
O_APPEND | O_WRONLY | O_CREAT,
S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
if (logfd == -1) {
SB_EERROR("ISE:write_logfile ", "unable to append logfile\n");
goto error;
}
if (0 != stat_ret)
_SB_WRITE_STR(
LOG_STRING
LOG_FMT_FUNC
LOG_FMT_ACCESS
LOG_FMT_PATH
LOG_FMT_APATH
LOG_FMT_RPATH
LOG_FMT_CMDLINE
);
/* Already have data in the log, so add a newline to space the
* log entries.
*/
_SB_WRITE_STR("\nF: ");
_SB_WRITE_STR(func);
_SB_WRITE_STR("\nS: ");
if (access)
_SB_WRITE_STR("allow");
else
_SB_WRITE_STR("deny");
_SB_WRITE_STR("\nP: ");
_SB_WRITE_STR(path);
_SB_WRITE_STR("\nA: ");
_SB_WRITE_STR(apath);
_SB_WRITE_STR("\nR: ");
_SB_WRITE_STR(rpath);
_SB_WRITE_STR("\nC: ");
int cmdlinefd = sb_open(PROC_SELF_CMDLINE, O_RDONLY, 0);
if (cmdlinefd != -1) {
size_t pagesz = getpagesize();
char *buf = xmalloc(pagesz);
while (1) {
size_t len = sb_read(cmdlinefd, buf, pagesz);
if (len == -1) {
SB_EERROR("ISE:write_logfile ", "cmdlinefd read error\n");
break;
} else if (!len)
break;
size_t i;
for (i = 0; i < len; ++i)
if (!buf[i])
buf[i] = ' ';
SB_WRITE(logfd, buf, len, error);
}
sb_close(cmdlinefd);
free(buf);
} else
_SB_WRITE_STR("");
_SB_WRITE_STR("\n");
return true;
error:
return false;
}
static void init_context(sbcontext_t *context)
{
memset(context, 0x00, sizeof(*context));
context->show_access_violation = true;
}
static void clean_env_entries(char ***prefixes_array, int *prefixes_num)
{
if (*prefixes_array == NULL)
return;
size_t i;
save_errno();
for (i = 0; i < *prefixes_num; ++i) {
if (NULL != (*prefixes_array)[i]) {
free((*prefixes_array)[i]);
(*prefixes_array)[i] = NULL;
}
}
if (NULL != *prefixes_array)
free(*prefixes_array);
*prefixes_array = NULL;
*prefixes_num = 0;
restore_errno();
}
#define pfx_num (*prefixes_num)
#define pfx_array (*prefixes_array)
#define pfx_item ((*prefixes_array)[(*prefixes_num)])
static void init_env_entries(char ***prefixes_array, int *prefixes_num, const char *env, const char *prefixes_env, int warn)
{
char *token = NULL;
char *rpath = NULL;
char *buffer = NULL;
char *buffer_ptr = NULL;
int prefixes_env_length = strlen(prefixes_env);
int num_delimiters = 0;
int i = 0;
int old_errno = errno;
if (NULL == prefixes_env) {
/* Do not warn if this is in init stage, as we might get
* issues due to LD_PRELOAD already set (bug #91431). */
if (sb_init)
fprintf(stderr,
"libsandbox: The '%s' env variable is not defined!\n",
env);
if (pfx_array) {
for (i = 0; i < pfx_num; i++)
free(pfx_item);
free(pfx_array);
}
pfx_num = 0;
goto done;
}
for (i = 0; i < prefixes_env_length; i++) {
if (':' == prefixes_env[i])
num_delimiters++;
}
/* num_delimiters might be 0, and we need 2 entries at least */
pfx_array = xmalloc(((num_delimiters * 2) + 2) * sizeof(char *));
buffer = strdup(prefixes_env);
buffer_ptr = buffer;
#ifdef HAVE_STRTOK_R
token = strtok_r(buffer_ptr, ":", &buffer_ptr);
#else
token = strtok(buffer_ptr, ":");
#endif
while ((NULL != token) && (strlen(token) > 0)) {
pfx_item = resolve_path(token, 0);
/* We do not care about errno here */
errno = 0;
if (NULL != pfx_item) {
pfx_num++;
/* Now add the realpath if it exists and
* are not a duplicate */
rpath = xmalloc(SB_PATH_MAX * sizeof(char));
pfx_item = realpath(*(&(pfx_item) - 1), rpath);
if ((NULL != pfx_item) &&
(0 != strcmp(*(&(pfx_item) - 1), pfx_item))) {
pfx_num++;
} else {
free(rpath);
pfx_item = NULL;
}
}
#ifdef HAVE_STRTOK_R
token = strtok_r(NULL, ":", &buffer_ptr);
#else
token = strtok(NULL, ":");
#endif
}
free(buffer);
done:
errno = old_errno;
return;
}
static int check_prefixes(char **prefixes, int num_prefixes, const char *path)
{
if (!prefixes)
return 0;
size_t i;
for (i = 0; i < num_prefixes; ++i)
if (prefixes[i] && !strncmp(path, prefixes[i], strlen(prefixes[i])))
return 1;
return 0;
}
static int check_access(sbcontext_t *sbcontext, int sb_nr, const char *func, const char *abs_path, const char *resolv_path)
{
int old_errno = errno;
int result = 0;
int retval;
retval = check_prefixes(sbcontext->deny_prefixes,
sbcontext->num_deny_prefixes, resolv_path);
if (1 == retval)
/* Fall in a read/write denied path, Deny Access */
goto out;
/* Hardcode denying write to the whole log dir. While this is a
* parial match and so rejects paths that also start with this
* string, that isn't going to happen in real life so live with
* it. We can't append a slash to this path either as that would
* allow people to open the dir itself for writing.
*/
if (!strncmp(resolv_path, SANDBOX_LOG_LOCATION, strlen(SANDBOX_LOG_LOCATION)))
goto out;
if (sbcontext->read_prefixes &&
(sb_nr == SB_NR_ACCESS_RD ||
sb_nr == SB_NR_OPEN_RD ||
/*sb_nr == SB_NR_POPEN ||*/
sb_nr == SB_NR_OPENDIR ||
/*sb_nr == SB_NR_SYSTEM ||
sb_nr == SB_NR_EXECL ||
sb_nr == SB_NR_EXECLP ||
sb_nr == SB_NR_EXECLE ||
sb_nr == SB_NR_EXECV ||
sb_nr == SB_NR_EXECVP ||*/
sb_nr == SB_NR_EXECVE))
{
retval = check_prefixes(sbcontext->read_prefixes,
sbcontext->num_read_prefixes, resolv_path);
if (1 == retval) {
/* Fall in a readable path, Grant Access */
result = 1;
goto out;
}
/* If we are here, and still no joy, and its the access() call,
* do not log it, but just return -1 */
if (sb_nr == SB_NR_ACCESS_RD) {
sbcontext->show_access_violation = false;
goto out;
}
}
if (sb_nr == SB_NR_ACCESS_WR ||
sb_nr == SB_NR_OPEN_WR ||
sb_nr == SB_NR_CREAT ||
sb_nr == SB_NR_CREAT64 ||
sb_nr == SB_NR_MKDIR ||
sb_nr == SB_NR_MKNOD ||
sb_nr == SB_NR_MKNODAT ||
sb_nr == SB_NR__XMKNOD ||
sb_nr == SB_NR___XMKNOD ||
sb_nr == SB_NR___XMKNODAT ||
sb_nr == SB_NR_MKFIFO ||
sb_nr == SB_NR_LINK ||
sb_nr == SB_NR_SYMLINK ||
sb_nr == SB_NR_RENAME ||
sb_nr == SB_NR_LUTIMES ||
sb_nr == SB_NR_UTIMENSAT ||
sb_nr == SB_NR_UTIME ||
sb_nr == SB_NR_UTIMES ||
sb_nr == SB_NR_FUTIMESAT ||
sb_nr == SB_NR_UNLINK ||
sb_nr == SB_NR_UNLINKAT ||
sb_nr == SB_NR_RMDIR ||
sb_nr == SB_NR_CHOWN ||
sb_nr == SB_NR_FCHOWNAT ||
sb_nr == SB_NR_LCHOWN ||
sb_nr == SB_NR_CHMOD ||
sb_nr == SB_NR_FCHMODAT ||
sb_nr == SB_NR_TRUNCATE ||
/*sb_nr == SB_NR_FTRUNCATE ||*/
sb_nr == SB_NR_TRUNCATE64/*||
sb_nr == SB_NR_FTRUNCATE64*/)
{
retval = check_prefixes(sbcontext->write_denied_prefixes,
sbcontext->num_write_denied_prefixes,
resolv_path);
if (1 == retval)
/* Falls in a write denied path, Deny Access */
goto out;
retval = check_prefixes(sbcontext->write_prefixes,
sbcontext->num_write_prefixes, resolv_path);
if (1 == retval) {
/* Falls in a writable path, Grant Access */
result = 1;
goto out;
}
/* XXX: Hack to enable us to remove symlinks pointing
* to protected stuff. First we make sure that the
* passed path is writable, and if so, check if its a
* symlink, and give access only if the resolved path
* of the symlink's parent also have write access. */
struct stat st;
if ((sb_nr == SB_NR_UNLINK ||
sb_nr == SB_NR_UNLINKAT ||
sb_nr == SB_NR_LCHOWN ||
sb_nr == SB_NR_RENAME ||
sb_nr == SB_NR_SYMLINK) &&
((-1 != lstat(abs_path, &st)) && (S_ISLNK(st.st_mode))))
{
/* Check if the symlink unresolved path have access */
retval = check_prefixes(sbcontext->write_prefixes,
sbcontext->num_write_prefixes, abs_path);
if (1 == retval) { /* Does have write access on path */
char *dname, *dname_buf, *rpath;
dname_buf = strdup(abs_path);
dname = dirname(dname_buf);
/* Get symlink resolved path */
rpath = resolve_path(dname, 1);
free(dname_buf);
if (NULL == rpath)
/* Don't really worry here about
* memory issues */
goto unlink_hack_end;
/* Now check if the symlink resolved path have access */
retval = check_prefixes(sbcontext->write_prefixes,
sbcontext->num_write_prefixes,
rpath);
free(rpath);
if (1 == retval) {
/* Does have write access on path, so
* enable the hack as it is a symlink */
result = 1;
goto out;
}
}
}
unlink_hack_end: ;
/* Hack to allow writing to '/proc/self/fd' #91516. It needs
* to be here as for each process, the '/proc/self' symlink
* will differ ...
*/
char proc_self_fd[SB_PATH_MAX];
if (!strncmp(resolv_path, PROC_DIR, strlen(PROC_DIR)) &&
NULL != realpath(PROC_SELF_FD, proc_self_fd) &&
!strncmp(resolv_path, proc_self_fd, strlen(proc_self_fd)))
{
result = 1;
goto out;
}
/* If operating on a location those parent dirs do not exist,
* then let it through as the OS itself will trigger a fail.
* This is like fopen("/foo/bar", "w") and /foo/ does not
* exist. All the functions filtered thus far fall into that
* behavior category, so no need to check the syscall.
*/
char *dname_buf = strdup(resolv_path);
int aret = sb_unwrapped_access(dirname(dname_buf), F_OK);
free(dname_buf);
if (aret) {
result = 1;
goto out;
}
retval = check_prefixes(sbcontext->predict_prefixes,
sbcontext->num_predict_prefixes, resolv_path);
if (1 == retval) {
/* Is a known access violation, so deny access,
* and do not log it */
sbcontext->show_access_violation = false;
goto out;
}
/* A very common bug (apparently) is for .py[co] files to fall out
* of sync with their .py source files. Rather than trigger a hard
* failure, let's just whine about it. Once python itself gets
* sorted out, we can drop this #256953.
*/
size_t len = strlen(resolv_path);
if (len > 4) {
const char *py = resolv_path + len - 4;
if (!strcmp(py, ".pyc") || !strcmp(py, ".pyo")) {
sbcontext->show_access_violation = false;
goto out;
}
}
/* If we are here, and still no joy, and its the access() call,
* do not log it, but just return -1 */
if (sb_nr == SB_NR_ACCESS_WR) {
sbcontext->show_access_violation = false;
goto out;
}
}
out:
errno = old_errno;
return result;
}
/* Return values:
* 0: failure, caller should abort
* 1: things worked out fine
* 2: things worked out fine, but the errno should not be restored
*/
static int check_syscall(sbcontext_t *sbcontext, int sb_nr, const char *func, const char *file)
{
char *absolute_path = NULL;
char *resolved_path = NULL;
char *log_path, *debug_log_path;
int old_errno = errno;
int result;
bool access, debug, verbose;
absolute_path = resolve_path(file, 0);
if (NULL == absolute_path)
goto error;
resolved_path = resolve_path(file, 1);
if (NULL == resolved_path)
goto error;
verbose = is_env_on(ENV_SANDBOX_VERBOSE);
log_path = getenv(ENV_SANDBOX_LOG);
debug = is_env_on(ENV_SANDBOX_DEBUG);
if (debug)
debug_log_path = getenv(ENV_SANDBOX_DEBUG_LOG);
result = check_access(sbcontext, sb_nr, func, absolute_path, resolved_path);
if (verbose) {
int sym_len = SB_MAX_STRING_LEN + 1 - strlen(func);
if (!result && sbcontext->show_access_violation)
SB_EERROR("ACCESS DENIED", " %s:%*s%s\n", func, sym_len, "", absolute_path);
else if (debug && sbcontext->show_access_violation)
SB_EINFO("ACCESS ALLOWED", " %s:%*s%s\n", func, sym_len, "", absolute_path);
else if (debug && !sbcontext->show_access_violation)
SB_EWARN("ACCESS PREDICTED", " %s:%*s%s\n", func, sym_len, "", absolute_path);
}
if ((0 == result) && sbcontext->show_access_violation)
access = false;
else
access = true;
if (log_path && !access) {
bool worked = write_logfile(log_path, func, file, absolute_path, resolved_path, access);
if (!worked && errno)
goto error;
}
if (debug_log_path && debug) {
bool worked = write_logfile(debug_log_path, func, file, absolute_path, resolved_path, access);
if (!worked && errno)
goto error;
}
if (NULL != absolute_path)
free(absolute_path);
if (NULL != resolved_path)
free(resolved_path);
errno = old_errno;
return result;
error:
if (NULL != absolute_path)
free(absolute_path);
if (NULL != resolved_path)
free(resolved_path);
/* The path is too long to be canonicalized, so just warn and let the
* function handle it (see bugs #21766 #94630 #101728 #227947)
*/
if (ENAMETOOLONG == errno)
return 2;
/* If we get here, something bad happened */
SB_EERROR("ISE ", "Unrecoverable error: %s\n", strerror(errno));
abort();
}
bool is_sandbox_on(void)
{
bool result;
save_errno();
/* $SANDBOX_ACTIVE is an env variable that should ONLY
* be used internal by sandbox.c and libsanbox.c. External
* sources should NEVER set it, else the sandbox is enabled
* in some cases when run in parallel with another sandbox,
* but not even in the sandbox shell.
*/
char *sb_env_active = getenv(ENV_SANDBOX_ACTIVE);
if (sandbox_on &&
sb_env_active &&
is_env_on(ENV_SANDBOX_ON) &&
(0 == strcmp(sb_env_active, SANDBOX_ACTIVE)))
result = true;
else
result = false;
restore_errno();
return result;
}
/* Need to protect the global sbcontext structure */
static pthread_mutex_t sb_syscall_lock = PTHREAD_MUTEX_INITIALIZER;
bool before_syscall(int dirfd, int sb_nr, const char *func, const char *file)
{
int old_errno = errno;
int result;
// static sbcontext_t sbcontext;
char *at_file_buf = NULL;
if (file == NULL || file[0] == '\0') {
/* The file/directory does not exist */
errno = ENOENT;
return false;
}
/* The *at style functions have the following semantics:
* - dirfd = AT_FDCWD: same as non-at func: file is based on CWD
* - file is absolute: dirfd is ignored
* - otherwise, file is relative to dirfd
* Since maintaining fd state based on open's, we'll just utilize
* the kernel doing it for us with /proc//fd/ ...
*/
if (dirfd != AT_FDCWD && file[0] != '/') {
at_file_buf = xmalloc(50 + strlen(file));
sprintf(at_file_buf, "/proc/%i/fd/%i/%s", getpid(), dirfd, file);
file = at_file_buf;
}
pthread_mutex_lock(&sb_syscall_lock);
if (!sb_init) {
init_context(&sbcontext);
sb_init = true;
}
char *sb_env_names[4] = {
ENV_SANDBOX_DENY,
ENV_SANDBOX_READ,
ENV_SANDBOX_WRITE,
ENV_SANDBOX_PREDICT,
};
size_t i;
for (i = 0; i < ARRAY_SIZE(sb_env_names); ++i) {
char *sb_env = getenv(sb_env_names[i]);
if ((!sb_env && cached_env_vars[i]) ||
!cached_env_vars[i] ||
strcmp(cached_env_vars[i], sb_env) != 0)
{
clean_env_entries(&(sbcontext.prefixes[i]),
&(sbcontext.num_prefixes[i]));
if (cached_env_vars[i])
free(cached_env_vars[i]);
if (sb_env) {
init_env_entries(&(sbcontext.prefixes[i]),
&(sbcontext.num_prefixes[i]), sb_env_names[i], sb_env, 1);
cached_env_vars[i] = strdup(sb_env);
} else
cached_env_vars[i] = NULL;
}
}
/* Might have been reset in check_access() */
sbcontext.show_access_violation = true;
result = check_syscall(&sbcontext, sb_nr, func, file);
pthread_mutex_unlock(&sb_syscall_lock);
if (at_file_buf)
free(at_file_buf);
if (0 == result) {
if ((NULL != getenv(ENV_SANDBOX_PID)) && (is_env_on(ENV_SANDBOX_ABORT)))
kill(atoi(getenv(ENV_SANDBOX_PID)), SIGUSR1);
/* FIXME: Should probably audit errno, and enable some other
* error to be returned (EINVAL for invalid mode for
* fopen() and co, ETOOLONG, etc). */
errno = EACCES;
} else if (result == 1)
errno = old_errno;
return result ? true : false;
}
bool before_syscall_access(int dirfd, int sb_nr, const char *func, const char *file, int flags)
{
const char *ext_func;
if (flags & W_OK)
sb_nr = SB_NR_ACCESS_WR, ext_func = "access_wr";
else
sb_nr = SB_NR_ACCESS_RD, ext_func = "access_rd";
return before_syscall(dirfd, sb_nr, ext_func, file);
}
bool before_syscall_open_int(int dirfd, int sb_nr, const char *func, const char *file, int flags)
{
const char *ext_func;
if ((flags & O_WRONLY) || (flags & O_RDWR))
sb_nr = SB_NR_OPEN_WR, ext_func = "open_wr";
else
sb_nr = SB_NR_OPEN_RD, ext_func = "open_rd";
return before_syscall(dirfd, sb_nr, ext_func, file);
}
bool before_syscall_open_char(int dirfd, int sb_nr, const char *func, const char *file, const char *mode)
{
if (NULL == mode)
return false;
const char *ext_func;
if ((*mode == 'r') && ((0 == (strcmp(mode, "r"))) ||
/* The strspn accept args are known non-writable modifiers */
(strlen(++mode) == strspn(mode, "xbtmce"))))
sb_nr = SB_NR_OPEN_RD, ext_func = "open_rd";
else
sb_nr = SB_NR_OPEN_WR, ext_func = "open_wr";
return before_syscall(dirfd, sb_nr, ext_func, file);
}