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libevil.c
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libevil.c
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/*
Copyright (c) 2011 Gluster, Inc. <http://www.gluster.com>
This file is part of GlusterFS.
GlusterFS is free software; you can redistribute it and/or modify
it under the terms of the GNU Affero General Public License as published
by the Free Software Foundation; either version 3 of the License,
or (at your option) any later version.
GlusterFS 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
Affero General Public License for more details.
You should have received a copy of the GNU Affero General Public License
along with this program. If not, see
<http://www.gnu.org/licenses/>.
*/
#include <dlfcn.h>
#include <sys/types.h>
#include <stdio.h>
#include <stdarg.h>
#include <stdlib.h>
#include <sys/time.h>
#include <utime.h>
#include <pthread.h>
#include <string.h>
#include <errno.h>
#include <fcntl.h>
#include <ftw.h>
#include <glob.h>
#include <ctype.h>
#include <sys/ptrace.h>
#include "libevil.h"
#include "md5.c"
static const char *protpatterns[] = {
EPOCH_FILE,
DEFAULT_FILE,
LICDIR,
LICDIR "/gpgv",
LICDIR "/pubring.gpg",
"/etc",
"/etc/ld.*.preload",
"/lib*",
"/lib*/libevil*.so",
NULL,
};
static const char *licensed_symbols[] = {
"iobuf_get",
"gf_log_init",
NULL,
};
static int le_debug = 0;
static long int default_timeout = 0;
static int
dbg (const char *fmt, ...)
{
int ret = 0;
va_list ap;
if (!le_debug)
return 0;
va_start (ap, fmt);
ret = vfprintf (stderr, fmt, ap);
va_end (ap);
return ret;
}
static int
err (const char *fmt, ...)
{
int ret = 0;
va_list ap;
va_start (ap, fmt);
ret = vfprintf (stderr, fmt, ap);
va_end (ap);
return ret;
}
static char *
strip_n (char *str)
{
char *n = NULL;
n = strchr (str, '\n');
if (n)
*n = '\0';
return str;
}
static void
dbg_init ()
{
if (getenv ("LE_DEBUG"))
le_debug = 1;
}
static int
globerr (const char *epath, int eerrno)
{
dbg ("%s: %s\n", epath, strerror (eerrno));
return 0;
}
struct permit_entry {
struct permit_entry *next;
unsigned char md5sum[16];
char *path;
};
static struct {
pthread_rwlock_t rwlock;
glob_t protglob;
struct stat *stats;
int permitcnt;
struct permit_entry *permits;
char macid[64];
pthread_t bigbro;
} protect;
static int is_signed_file (const char *filename);
static void
__rehash_glob (void)
{
int ret = 0;
int i = 0;
int globflags = GLOB_BRACE;
const char *pattern = NULL;
char **files = NULL;
struct stat *stats = NULL;
if (protect.protglob.gl_pathc) {
globfree (&protect.protglob);
protect.protglob.gl_pathc = 0;
if (protect.stats)
free (protect.stats);
protect.stats = NULL;
}
for (i = 0; (pattern = protpatterns[i]); i++) {
ret = glob (pattern, globflags, globerr, &protect.protglob);
if (ret && ret != GLOB_NOMATCH) {
globfree (&protect.protglob);
protect.protglob.gl_pathc = 0;
return;
}
globflags |= GLOB_APPEND;
}
files = protect.protglob.gl_pathv;
stats = calloc (protect.protglob.gl_pathc, sizeof (*stats));
if (!stats) {
globfree (&protect.protglob);
protect.protglob.gl_pathc = 0;
return;
}
for (i = 0; i < protect.protglob.gl_pathc; i++) {
ret = lstat (files[i], &stats[i]);
if (ret == 0) {
#if 0
dbg ("%s: %lld/%lld\n", files[i],
(long long) (stats[i].st_ino),
(long long) (stats[i].st_dev));
#endif
} else {
dbg ("%s: %s\n", files[i], strerror (errno));
}
}
protect.stats = stats;
return;
}
static void
rehash_glob (void)
{
pthread_rwlock_wrlock (&protect.rwlock);
{
__rehash_glob ();
}
pthread_rwlock_unlock (&protect.rwlock);
}
static void
prepare_glob (void)
{
pthread_rwlock_init (&protect.rwlock, NULL);
rehash_glob ();
}
static int
__is_protected_atpath (int dirfd, const char *path, int follow)
{
int i = 0;
int pathc = 0;
struct stat *stats = NULL;
struct stat mystat = {0, };
int ret = 0;
int flags = AT_SYMLINK_NOFOLLOW;
pathc = protect.protglob.gl_pathc;
stats = protect.stats;
if (follow)
flags = 0;
ret = fstatat (dirfd, path, &mystat, flags);
if (ret)
return NO;
for (i = 0; i < pathc; i++) {
if (stats[i].st_ino == mystat.st_ino
&& stats[i].st_dev == mystat.st_dev)
return YES;
}
return NO;
}
static int
__is_protected_atfile (int dirfd, const char *path)
{
return __is_protected_atpath (dirfd, path, 1);
}
static int
is_protected_atfile (int dirfd, const char *path)
{
int ret = 0;
pthread_rwlock_rdlock (&protect.rwlock);
{
ret = __is_protected_atfile (dirfd, path);
}
pthread_rwlock_unlock (&protect.rwlock);
return ret;
}
static int
__is_protected_atentry (int dirfd, const char *path)
{
return __is_protected_atpath (dirfd, path, 0);
}
static int
is_protected_atentry (int dirfd, const char *path)
{
int ret = 0;
pthread_rwlock_rdlock (&protect.rwlock);
{
ret = __is_protected_atentry (dirfd, path);
}
pthread_rwlock_unlock (&protect.rwlock);
return ret;
}
static int
is_protected_file (const char *path)
{
int ret = 0;
pthread_rwlock_rdlock (&protect.rwlock);
{
ret = __is_protected_atfile (AT_FDCWD, path);
}
pthread_rwlock_unlock (&protect.rwlock);
return ret;
}
static int
is_protected_entry (const char *path)
{
int ret = 0;
pthread_rwlock_rdlock (&protect.rwlock);
{
ret = __is_protected_atentry (AT_FDCWD, path);
}
pthread_rwlock_unlock (&protect.rwlock);
return ret;
}
static int
__is_protected_fd (int fd)
{
int i = 0;
int pathc = 0;
struct stat *stats = NULL;
struct stat mystat = {0, };
int ret = 0;
pathc = protect.protglob.gl_pathc;
stats = protect.stats;
ret = fstat (fd, &mystat);
if (ret)
return NO;
for (i = 0; i < pathc; i++) {
if (stats[i].st_ino == mystat.st_ino
&& stats[i].st_dev == mystat.st_dev)
return YES;
}
return NO;
}
static int
is_protected_fd (int fd)
{
int ret = 0;
pthread_rwlock_rdlock (&protect.rwlock);
{
ret = __is_protected_fd (fd);
}
pthread_rwlock_unlock (&protect.rwlock);
return ret;
}
static time_t
get_default_deadline (void)
{
struct stat epoch_stat = {0, };
int ret = 0;
time_t epoch = 0;
ret = lstat (EPOCH_FILE, &epoch_stat);
if (ret != 0)
return 0;
epoch = epoch_stat.st_ctime;
if (epoch_stat.st_mtime < epoch)
epoch = epoch_stat.st_mtime;
if (epoch_stat.st_atime < epoch)
epoch = epoch_stat.st_atime;
return (epoch + default_timeout);
}
static time_t
license_parse (FILE *fp)
{
char line[1024];
char *l = NULL;
char *saveptr = NULL;;
char *macid = NULL;
char *timestamp = NULL;
char *end = NULL;
time_t final_ts = 0;
time_t ts = 0;
char timebuf[64];
while ((l = fgets (line, 1024, fp))) {
macid = strtok_r (line, " \r\n\t", &saveptr);
if (!macid)
continue;
if (strcmp (macid, protect.macid) != 0) {
macid = NULL;
continue;
}
dbg ("found entry macid=%s\n", macid);
timestamp = strtok_r (NULL, " \r\n\t", &saveptr);
if (!timestamp) {
macid = NULL;
continue;
}
dbg ("found timestamp %s for macid=%s\n", timestamp, macid);
ts = strtoul (timestamp, &end, 10);
if (*end != '\0') {
macid = NULL;
timestamp = NULL;
continue;
}
if (ts > final_ts)
final_ts = ts;
}
dbg ("final timestamp = %llu (%s)\n", (unsigned long long) final_ts,
strip_n (ctime_r (&final_ts, timebuf)));
return final_ts;
}
static time_t
get_license_deadline (void)
{
int ret = 0;
struct stat lic_stat = {0, };
static struct stat lic_stat_prev = {0, };
static time_t lic_deadline = 0;
FILE *lfp = NULL;
/* be symlink friendly */
ret = stat (LICFILE, &lic_stat);
if (ret)
return 0;
if (lic_stat.st_mtime == lic_stat_prev.st_mtime &&
lic_stat.st_ctime == lic_stat_prev.st_ctime &&
lic_stat.st_ino == lic_stat_prev.st_ino &&
lic_stat.st_dev == lic_stat_prev.st_dev) {
/* nothing changed */
return lic_deadline;
}
lfp = fopen (LICFILE, "r");
if (!lfp)
return 0;
ret = is_signed_file (LICFILE);
if (ret != YES) {
fclose (lfp);
return 0;
}
lic_deadline = license_parse (lfp);
lic_stat_prev = lic_stat;
fclose (lfp);
return lic_deadline;
}
static time_t
get_latest_deadline (void)
{
time_t def_deadline = 0;
time_t lic_deadline = 0;
time_t deadline = 0;
char timebuf1[64];
char timebuf2[64];
def_deadline = get_default_deadline ();
lic_deadline = get_license_deadline ();
dbg ("def_deadline = %s lic_deadline=%s\n",
strip_n (ctime_r (&def_deadline, timebuf1)),
strip_n (ctime_r (&lic_deadline, timebuf2)));
deadline = MAX (def_deadline, lic_deadline);
return deadline;
}
static void *
bigbro_is_watching (void *data)
{
int can_live = YES;
time_t deadline = -1;
time_t new_deadline = 0;
time_t now = 0;
char timebuf1[64];
char timebuf2[64];
for (can_live = YES; can_live == YES; sleep (10)) {
new_deadline = get_latest_deadline ();
if (deadline != new_deadline) {
dbg ("updated deadline: %s\n",
strip_n (ctime_r (&new_deadline, timebuf1)));
}
deadline = new_deadline;
now = time (NULL);
if (deadline < now) {
err ("deadline was: %s, now is: %s\n",
strip_n (ctime_r (&deadline, timebuf1)),
strip_n (ctime_r (&now, timebuf2)));
/* >:) */
break;
}
}
exit (1);
return NULL;
}
static void
bb_child (void)
{
int ret = 0;
ret = pthread_create (&protect.bigbro, NULL, bigbro_is_watching, NULL);
if (ret != 0)
protect.bigbro = 0;
}
static void
big_brother_kickoff (void)
{
int ret = 0;
ret = pthread_atfork (NULL, NULL, bb_child);
if (ret != 0) {
dbg ("failed pthread_atfork (%s)\n", strerror (errno));
return;
}
ret = pthread_create (&protect.bigbro, NULL, bigbro_is_watching, NULL);
if (ret != 0)
protect.bigbro = 0;
}
static int is_licensed = -1;
static int
is_licensed_prog (void)
{
int i = 0;
const char *symbol = NULL;
if (is_licensed == -1) {
for (i = 0; (symbol = licensed_symbols[i]); i++) {
if (dlsym (RTLD_NEXT, symbol) != NULL) {
is_licensed = 1;
break;
}
}
if (!symbol)
is_licensed = 0;
if (is_licensed) {
dbg ("found symbol %s -- is a licensed program\n",
symbol);
big_brother_kickoff ();
}
}
return is_licensed;
}
static void
make_licensed_prog (void)
{
if (is_licensed == 1)
return;
is_licensed = 1;
big_brother_kickoff ();
}
static int
is_signed_file (const char *filename)
{
int len = 0;
int ret = 0;
int status = 0;
char cmdbuf[1024];
len = snprintf (cmdbuf, 1024, "%s/gpgv --keyring %s/pubring.gpg %s >/dev/null 2>&1",
LICDIR, LICDIR, filename);
if (len >= 1024) {
dbg ("cmd too long (%d)\n", len);
return NO;
}
status = system (cmdbuf);
ret = WEXITSTATUS(status);
dbg ("%s: %d\n", cmdbuf, status);
if (ret == 0)
return YES;
return NO;
}
static int
__line_has_md5str (const char *line)
{
int i = 0;
int ch = 0;
for (i = 0; i < 32; i++) {
ch = line[i];
if (!isxdigit (ch))
return NO;
}
ch = line[i];
if (!isspace (ch))
return NO;
for (ch = line[i]; (ch = line[i]) && (isspace (ch)); i++);
for (ch = line[i]; (ch = line[i]); i++)
if (!isascii (ch))
return NO;
return YES;
}
static int
xnum (char ch)
{
int n = 0;
if (isdigit (ch))
n = (ch - '0');
if (ch >= 'a' && ch <= 'f')
n = (ch - 'a' + 10);
if (ch >= 'A' && ch <= 'F')
n = (ch - 'A' + 10);
return n;
}
static void
md5str_to_md5sum (const char *str, unsigned char *sum)
{
int i = 0;
int j = 0;
int ch = 0;
for (i = 0; i < 32; i++) {
if (!(i % 2)) {
ch = xnum (str[i]);
continue;
}
ch <<= 4;
ch += xnum (str[i]);
sum[j] = ch;
j++;
}
}
static int
permits_parse (FILE *fp)
{
struct permit_entry *entry = NULL;
struct permit_entry *next = NULL;
struct permit_entry *head = NULL;
char line[1024];
char *l = NULL;
while ((l = fgets (line, 1024, fp))) {
if (strlen (l) < 35)
continue;
if (__line_has_md5str (l) != YES)
continue;
entry = calloc (1, sizeof (*entry));
if (!entry)
goto err;
entry->next = head;
head = entry;
md5str_to_md5sum (l, entry->md5sum);
for (l = &line[32]; *l; l++)
if (!isspace (*l))
break;
if (!(*l))
goto err;
entry->path = strdup (l);
if (!entry->path)
goto err;
l = strchr (entry->path, '\n');
if (l)
*l = '\0';
l = strchr (entry->path, '\r');
if (l)
*l = '\0';
}
protect.permits = head;
return YES;
err:
for (entry = head; entry; entry = next) {
next = entry->next;
if (entry->path)
free (entry->path);
free (entry);
}
return NO;
}
static int
permits_load (void)
{
const char *permitfile = NULL;
FILE *permitfp = NULL;
struct stat stbuf;
int ret = 0;
if (protect.permits)
return YES;
permitfile = getenv ("LE_PERMIT");
if (!permitfile)
permitfile = PERMITFILE;
ret = stat (permitfile, &stbuf);
/* don't care if it is symlink */
if (ret != 0) {
dbg ("%s: %s\n", permitfile, strerror (errno));
return NO;
}
if (!S_ISREG (stbuf.st_mode)) {
dbg ("%s: Not a regular file\n", permitfile);
return NO;
}
permitfp = fopen (permitfile, "r");
if (!permitfp) {
dbg ("%s: %s\n", permitfile, strerror (errno));
return NO;
}
ret = is_signed_file (permitfile);
/* TODO: provide is_signed_fd which uses is_signed_file with
/proc/getpid()/fd/%d as filename
*/
if (ret != YES) {
dbg ("%s: signature check failed\n", permitfile);
fclose (permitfp);
return NO;
}
ret = permits_parse (permitfp);
fclose (permitfp);
return ret;
}
const char *
get_permitted_path (unsigned char md5sum[16])
{
struct permit_entry *entry = NULL;
for (entry = protect.permits; entry; entry = entry->next) {
if (memcmp (md5sum, entry->md5sum, 16) == 0)
return entry->path;
}
return NULL;
}
static int
is_permitted_renameat (int olddirfd, const char *oldpath,
int newdirfd, const char *newpath)
{
struct stat attempted_dst_stat = {0,};
struct stat permitted_dst_stat = {0,};
struct stat src_stat = {0, };
int ret = 0;
unsigned char md5sum[16];
const char *permitted_path = NULL;
ret = fstatat (newdirfd, newpath, &attempted_dst_stat,
AT_SYMLINK_NOFOLLOW);
if (ret != 0)
return NO;
ret = fstatat (olddirfd, oldpath, &src_stat,
AT_SYMLINK_NOFOLLOW);
if (ret != 0)
return NO;
if (!S_ISREG (src_stat.st_mode))
return NO;
ret = libevil_md5sum_file (olddirfd, oldpath, md5sum);
if (ret != 0)
return NO;
ret = permits_load ();
if (ret != YES)
return NO;
permitted_path = get_permitted_path (md5sum);
if (!permitted_path)
return NO;
dbg ("permitted: %s\n", permitted_path);
ret = lstat (permitted_path, &permitted_dst_stat);
if (ret != 0) {
dbg ("%s: %s\n", permitted_path, strerror (errno));
return NO;
}
dbg ("cmp p_i=%llu,p_d=%llu a_i=%llu,a_d=%llu\n",
(unsigned long long) (permitted_dst_stat.st_ino),
(unsigned long long) (permitted_dst_stat.st_dev),
(unsigned long long) (attempted_dst_stat.st_ino),
(unsigned long long) (attempted_dst_stat.st_dev));
if (permitted_dst_stat.st_ino == attempted_dst_stat.st_ino &&
permitted_dst_stat.st_dev == attempted_dst_stat.st_dev)
return YES;
return NO;
}
static int
is_permitted_rename (const char *oldpath, const char *newpath)
{
return is_permitted_renameat (AT_FDCWD, oldpath, AT_FDCWD, newpath);
}
int
TRAP (rename, (const char *oldpath, const char *newpath))
{
int ret = 0;
if (is_licensed_prog ())
goto green;
if (is_protected_entry (oldpath))
goto red;
if (!is_protected_entry (newpath))
goto green;
if (!is_permitted_rename (oldpath, newpath))
goto red;
green:
ret = real_rename (oldpath, newpath);
return ret;
red:
errno = EPERM;
return -1;
}
int
TRAP (renameat, (int olddirfd, const char *oldpath,
int newdirfd, const char *newpath))
{
int ret = 0;
if (is_licensed_prog ())
goto green;
if (is_protected_atentry (olddirfd, oldpath))
goto red;
if (!is_protected_atentry (newdirfd, newpath))
goto green;
if (!is_permitted_renameat (olddirfd, oldpath, newdirfd, newpath))
goto red;
green:
ret = real_renameat (olddirfd, oldpath,
newdirfd, newpath);
return ret;
red:
errno = EPERM;
return -1;
}
int
TRAP (unlink, (const char *pathname))
{
int ret = 0;
if (is_licensed_prog ())
goto green;
if (is_protected_entry (pathname))
goto red;
green:
ret = real_unlink (pathname);
return ret;
red:
errno = EPERM;
return -1;
}
int
TRAP (unlinkat, (int dirfd, const const char *pathname, int flags))
{
int ret = 0;
if (is_licensed_prog ())
goto green;
if (is_protected_atentry (dirfd, pathname))
goto red;
green:
ret = real_unlinkat (dirfd, pathname, flags);
return ret;
red:
errno = EPERM;
return -1;
}
int
TRAP (remove, (const char *pathname))
{
int ret = 0;
if (is_licensed_prog ())
goto green;
if (is_protected_entry (pathname))