/*************************************************************************
* (C) 2009 AITNET - Sofia/Bulgaria - <office@aitbg.com>
* by Michael Pounov <misho@aitbg.com>
*
* $Author: misho $
* $Id: cfexec.c,v 1.5.20.10 2021/03/21 01:30:19 misho Exp $
*
*************************************************************************
The ELWIX and AITNET software is distributed under the following
terms:
All of the documentation and software included in the ELWIX and AITNET
Releases is copyrighted by ELWIX - Sofia/Bulgaria <info@elwix.org>
Copyright 2004 - 2021
by Michael Pounov <misho@elwix.org>. All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
3. All advertising materials mentioning features or use of this software
must display the following acknowledgement:
This product includes software developed by Michael Pounov <misho@elwix.org>
ELWIX - Embedded LightWeight unIX and its contributors.
4. Neither the name of AITNET nor the names of its contributors
may be used to endorse or promote products derived from this software
without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY AITNET AND CONTRIBUTORS ``AS IS'' AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
SUCH DAMAGE.
*/
#include "global.h"
cfg_root_t cfg;
int Verbose, Timeout, kq;
ait_val_t User, Mount, Chroot;
char szSess[MAXPATHLEN], szSLCK[MAXPATHLEN], szConfig[MAXPATHLEN];
extern char compiled[], compiledby[], compilehost[];
static void
Usage()
{
printf( "CFExec is tool for managment R/W operation with CompactFlash\n"
"=== %s === %s@%s ===\n\n"
" Syntax: cfexec [options] [exec_file]\n\n"
"\t-v\t\tVerbose ...\n"
"\t-C <config>\tLoad config [default=/etc/cfexec.conf]\n"
"\t-c <dir>\tAfter execute chroot to dir [default=/]\n"
"\t-u <user>\tAfter execute suid to user [default=root]\n"
"\t-m <mnt>\tOther mount dir [default=/]\n"
"\t-t <sec>\tTimeout for autolock mount dir after seconds [default=300]\n"
"\t-L <reason>\tService lock and set RW state of device with reason\n"
"\t-U \t\tService unlock and set RO state of device\n"
"\n", compiled, compiledby, compilehost);
}
struct statfs *
getmntpt(const char *name)
{
struct statfs *mntbuf;
int i, mntsize;
mntsize = getmntinfo(&mntbuf, MNT_NOWAIT);
for (i = mntsize - 1; i >= 0; i--) {
if (!strcmp(mntbuf[i].f_mntfromname, name) ||
!strcmp(mntbuf[i].f_mntonname, name))
return &mntbuf[i];
}
return NULL;
}
static int
update(int flags)
{
struct statfs *mntfs = getmntpt(AIT_GET_STR(&Mount));
char errmsg[STRSIZ] = { [0 ... STRSIZ - 1] = 0 };
#ifdef __NetBSD__
struct ufs_args mnt;
memset(&mnt, 0, sizeof mnt);
mnt.fspec = mntfs->f_mntfromname;
if (mount(mntfs->f_fstypename, mntfs->f_mntonname, flags, &mnt, sizeof mnt) == -1) {
#else
iovec_t *iov;
int ret;
iov = iov_Init();
if (!iov)
return -1;
if (flags & MNT_RDONLY)
iov_PushPair(iov, "ro", "", 0);
else
iov_PushPair(iov, "noro", "", 0);
iov_PushPair(iov, "update", "", 0);
iov_PushPair(iov, "fstype", mntfs->f_fstypename, (size_t) -1);
iov_PushPair(iov, "fspath", mntfs->f_mntonname, (size_t) -1);
iov_PushPair(iov, "from", mntfs->f_mntfromname, (size_t) -1);
iov_PushPair(iov, "errmsg", errmsg, sizeof errmsg);
ret = nmount(iov_Array(iov), iov_Size(iov), flags);
iov_FreePairs(iov, 0);
iov_Destroy(&iov);
if (ret == -1) {
#endif
printf("Error:: can`t update mount %s %s #%d - %s\n", AIT_GET_STR(&Mount),
errmsg, errno, strerror(errno));
return -1;
}
VERB(5) printf("Info(5):: safe mount %s for device %s to %s operation (%s)\n",
mntfs->f_fstypename, mntfs->f_mntfromname, mntfs->f_mntonname,
(flags & MNT_RDONLY) ? "ro" : "rw");
return 0;
}
static void
setuser()
{
struct passwd *pw;
pw = getpwnam(AIT_GET_LIKE(&User, char*));
if (pw) {
setuid(pw->pw_uid);
setgid(pw->pw_gid);
endpwent();
VERB(5) printf("Info(5):: Suid to user %s.\n", AIT_GET_STR(&User));
} else
VERB(5) printf("Info(5):: Can`t suid to user %s !\n", AIT_GET_STR(&User));
}
static int
mkevent(struct kevent *chg, struct kevent *evt)
{
int f;
char szStr[STRSIZ];
f = open(szSess, O_CREAT | O_WRONLY | O_TRUNC, 0644);
if (f == -1) {
printf("Error:: can`t lock session #%d - %s\n", errno, strerror(errno));
return -1;
} else {
memset(szStr, 0, sizeof szStr);
snprintf(szStr, sizeof szStr, "%d", getpid());
write(f, szStr, strlen(szStr));
}
VERB(3) printf("Created lock file %s\n", szSess);
if (chg && evt) {
kq = kqueue();
if (kq == -1) {
printf("Error:: can`t execute safe mount #%d - %s\n", errno, strerror(errno));
close(f);
unlink(szSess);
return -1;
} else {
memset(chg, 0, sizeof(struct kevent));
memset(evt, 0, sizeof(struct kevent));
EV_SET(chg, f, EVFILT_VNODE, EV_ADD, NOTE_DELETE | NOTE_RENAME | NOTE_REVOKE,
0, NULL);
}
}
return f;
}
static void
cleanexit()
{
AIT_FREE_VAL(&User);
AIT_FREE_VAL(&Mount);
AIT_FREE_VAL(&Chroot);
}
static int
s_unlck()
{
if (access(szSLCK, F_OK))
return 2;
if (access(szSess, F_OK) && update(MNT_UPDATE | MNT_RDONLY) == -1)
return 8;
unlink(szSLCK);
VERB(3) printf("Unlock & deleted service lock file %s\n", szSLCK);
return 0;
}
static int
s_lck(const char *reason)
{
int f;
char szStr[STRSIZ];
if (!access(szSLCK, F_OK)) {
printf("cfexec already held service lock ...\n");
return 127;
}
f = open(szSLCK, O_CREAT | O_WRONLY | O_TRUNC, 0644);
if (f == -1) {
printf("Error:: can`t service lock session #%d - %s\n", errno, strerror(errno));
return 4;
} else {
memset(szStr, 0, sizeof szStr);
snprintf(szStr, sizeof szStr, "[%d] - %s", getpid(), reason);
write(f, szStr, strlen(szStr));
}
close(f);
if (update(MNT_UPDATE) == -1) {
unlink(szSLCK);
return 5;
}
VERB(3) printf("Lock & created service lock file %s\n", szSLCK);
return 0;
}
int
main(int argc, char **argv)
{
char ch, mod = 0, reason[STRSIZ];
const char *err = NULL;
struct kevent chg, evt;
struct timespec ts;
pid_t pid;
int f, ret = 0, stat = 0;
strlcpy(szConfig, DEFAULT_CONFIG, MAXPATHLEN);
/* Load variables from config if exists */
if (!cfgLoadConfig(szConfig, &cfg)) {
cfg_loadAttribute(&cfg, "cfexec", "timeout", &User, DEFAULT_TIMEOUT);
#ifndef HAVE_STRTONUM
Timeout = (int) strtol(szUser, NULL, 0);
#else
Timeout = strtonum(AIT_GET_STR(&User), 0, 3600, &err);
#endif
AIT_FREE_VAL(&User);
if (!Timeout && err) {
printf("Error:: in seconds for timeout %s - %s\n", optarg, err);
cfgUnloadConfig(&cfg);
return 1;
}
cfg_loadAttribute(&cfg, "cfexec", "suid", &User, DEFAULT_USER);
cfg_loadAttribute(&cfg, "cfexec", "mount", &Mount, DEFAULT_MOUNT);
cfg_loadAttribute(&cfg, "cfexec", "chroot", &Chroot, DEFAULT_CHROOT);
cfgUnloadConfig(&cfg);
} else {
Timeout = atoi(DEFAULT_TIMEOUT);
AIT_SET_STR(&User, DEFAULT_USER);
AIT_SET_STR(&Mount, DEFAULT_MOUNT);
AIT_SET_STR(&Chroot, DEFAULT_CHROOT);
}
atexit(cleanexit);
/* Load variables from arguments if exists */
while ((ch = getopt(argc, argv, "hvUC:u:c:m:t:L:")) != -1)
switch (ch) {
case 'C':
if (!cfgLoadConfig(optarg, &cfg)) {
cfg_loadAttribute(&cfg, "cfexec", "timeout", &User, DEFAULT_TIMEOUT);
#ifndef HAVE_STRTONUM
Timeout = (int) strtol(szUser, NULL, 0);
#else
Timeout = strtonum(AIT_GET_STR(&User), 0, 3600, &err);
#endif
AIT_FREE_VAL(&User);
if (!Timeout && err) {
printf("Error:: in seconds for timeout %s - %s\n", optarg, err);
cfgUnloadConfig(&cfg);
return 1;
}
cfg_loadAttribute(&cfg, "cfexec", "suid", &User, DEFAULT_USER);
cfg_loadAttribute(&cfg, "cfexec", "mount", &Mount, DEFAULT_MOUNT);
cfg_loadAttribute(&cfg, "cfexec", "chroot", &Chroot, DEFAULT_CHROOT);
cfgUnloadConfig(&cfg);
}
break;
case 'v':
Verbose++;
break;
case 'u':
AIT_SET_STR(&User, optarg);
break;
case 'c':
AIT_SET_STR(&Chroot, optarg);
break;
case 'm':
AIT_SET_STR(&Mount, optarg);
break;
case 'L':
strlcpy(reason, optarg, sizeof reason);
mod = 1;
break;
case 'U':
mod = -1;
break;
case 't':
#ifndef HAVE_STRTONUM
Timeout = (int) strtol(optarg, NULL, 0);
#else
Timeout = strtonum(optarg, 0, 3600, &err);
#endif
if (!Timeout && err) {
printf("Error:: in seconds for timeout %s - %s\n",
optarg, err);
return 1;
}
break;
case 'h':
default:
Usage();
return 1;
}
argc -= optind;
argv += optind;
memset(szSess, 0, MAXPATHLEN);
snprintf(szSess, MAXPATHLEN, "%s%s-cfexec.LCK", DEFAULT_TMP, AIT_GET_STR(&Mount));
memset(szSLCK, 0, MAXPATHLEN);
snprintf(szSLCK, MAXPATHLEN, "%s%s-SYS-cfexec.LCK", DEFAULT_TMP, AIT_GET_STR(&Mount));
/* we have request for service lock! */
if (mod) {
VERB(3) printf("Info(3):: mode=%hhd\n", mod);
if (mod == -1)
ret = s_unlck();
else
ret = s_lck(reason);
return ret;
}
VERB(3) printf("Info(3):: Chroot=%s SUID=%s Mount=%s Timeout=%d Session=%s\n",
AIT_GET_STR(&Chroot), AIT_GET_STR(&User),
AIT_GET_STR(&Mount), Timeout, szSess);
if (!access(szSess, F_OK)) {
printf("cfexec already running ...\n");
return 127;
}
if (!argc) {
switch (fork()) {
case -1:
printf("Error:: can`t execute safe mount #%d - %s\n",
errno, strerror(errno));
return 3;
case 0:
VERB(5) printf("Info(5):: Go safe mount.\n");
setsid();
if ((f = mkevent(&chg, &evt)) == -1)
return 4;
if (update(MNT_UPDATE) == -1) {
stat = 5;
goto skip;
}
if (Timeout) {
memset(&ts, 0, sizeof ts);
ts.tv_sec = Timeout;
}
switch (kevent(kq, &chg, 1, &evt, 1, !Timeout ? NULL : &ts)) {
case -1:
printf("Error:: can`t execute safe mount #%d - %s\n",
errno, strerror(errno));
stat = 7;
break;
case 0:
if (!access(szSLCK, F_OK)) {
VERB(1) printf("Timeout reached - service locked\n");
break;
}
VERB(1) printf("Timeout reached - secure mount\n");
default:
VERB(1) printf("Lock file is deleted - secure mount\n");
if (access(szSLCK, F_OK) && update(MNT_UPDATE | MNT_RDONLY) == -1)
stat = 8;
}
skip:
close(kq);
close(f);
unlink(szSess);
break;
}
} else {
/*
sigemptyset(&sig);
sigaddset(&sig, SIGINT);
sigaddset(&sig, SIGTSTP);
sigprocmask(SIG_BLOCK, &sig, &oldsig);
*/
if ((f = mkevent(NULL, NULL)) == -1)
return 4;
else
close(f);
if (update(MNT_UPDATE) == -1) {
unlink(szSess);
return 5;
}
switch ((pid = vfork())) {
case -1:
printf("Error:: can`t execute safe mount #%d - %s\n",
errno, strerror(errno));
stat = 3;
break;
case 0:
VERB(5) printf("Go to running process %s\n", *argv);
if (chroot(AIT_GET_STR(&Chroot)) == -1) {
printf("Error:: can`t chroot to dir %s #%d - %s\n",
AIT_GET_STR(&Chroot), errno, strerror(errno));
} else {
if (strncmp(AIT_GET_STR(&User), "root", 5))
setuser();
/* chdir("/"); */
execvp(*argv, argv);
}
_exit(127);
break;
default:
waitpid(pid, &stat, 0);
stat = WEXITSTATUS(stat);
VERB(3) printf("Return code: %d\n", stat);
if (access(szSLCK, F_OK) && update(MNT_UPDATE | MNT_RDONLY) == -1)
stat = 8;
break;
}
unlink(szSess);
}
return stat;
}
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