exec.c 1.0.4 is a kernel module which logs all the commands executed on the system. Extremely powerful stealth logging made easy!
47045736259814379eccdb697872f3a3b8d3da557a518d496ecce9188a64fe61
/* exec.c 1.0.4 by Pat Szuta <perly@xnet.com>
*
* exec.c is a kernel module which allows administrators to log all the
* commands executed by users. Although many have done this sort of
* thing, I haven't seen any public releases, so here it is.
* The basic output looks like this:
Nov 15 00:42:27 perly kernel: EXECVE(0)[4837]: /bin/ps uax
* The EXECVE()[] format is: EXECVE(UID)[PID].
* I suggest redirecting kern.info to your own file, because that's where
* exec.c will log its stuff. You can do this by adding this line to
* your /etc/sysconf.log, and restarting it:
kern.info /path/to/myfile
* Applaud gersh for catching a nasty little syslog thingy that caused
* the output to be printed twice.
* Do whatever you want with this code, just leave my name on it. If you
* have any comments/questions/mods, send them to perly@xnet.com
* Oh, and if you do use this module, drop me an email, so that if I
* update it, you'll be the first one to know. Good luck :)
* To compile and execute:
gcc exec.c -c
insmod exec.o
* Changelog:
dec 6, 99
I have just recieved an email from Pavel Urban (<urbanp@mlp.cz>) with
code to fix a major bug!! Thanks Pavel!!!!!!
He says that the accual person who found the bug is Belgarat
(svatopluk.dedic@netbeans.cz). Thanks a lot to him too!
nov 18, 99
Recieving not too many complaints, I have decided to make this into
a stable version.
I have noticed that if a user does 'ls *' in a big directory, the shell
will expand the * to all the files in the directory and pass them as
arguments. Thus I have limited the number of arguments logged to 10.
This should be enough for everyone, and enough to keep syslog from
bugging you about long prints :) (You can change the define if you want
to).
nov 18, 99
After a bug report, I have improved the pointer error checking routine.
Before it would not log any arguments, now it should. Note that this is
the beta version.
nov 15, 99
Gersh caught a rather nasty bug. If a user wrote a program which did
execl("some", "stuff"); without a NULL at the end, the kernel would
oops. So, I added a little pointer checking.
*/
#define MODULE
#define __KERNEL__
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/sched.h>
#include <linux/unistd.h>
#include <sys/syscall.h>
#include <linux/mm.h>
#include <linux/smp_lock.h>
#include <asm/ptrace.h>
#include <errno.h>
#define ARGS_LOGGED 10 /* Max number of arguments logged */
int (*orig_execve)(struct pt_regs);
void execve_log(char *, char **);
extern void *sys_call_table[];
int hacked_execve(struct pt_regs regs)
{
int error;
char * filename;
lock_kernel();
filename = getname((char *) regs.ebx);
error = PTR_ERR(filename);
if (IS_ERR(filename))
goto out;
execve_log(filename, (char **) regs.ecx);
error = do_execve(filename, (char **) regs.ecx, (char **) regs.edx, ®s);
if (error == 0)
current->flags &= ~PF_DTRACE;
putname(filename);
out:
unlock_kernel();
return error;
}
void execve_log(char *file, char **argv)
{
int args_logged = ARGS_LOGGED;
char *tmp; /* pavel/belgarat's fix */
printk(KERN_INFO "EXECVE(%d)[%d]: %s ", current->uid, current->pid,
file);
*argv++;
while(*argv && args_logged--)
{
if(IS_ERR(tmp = getname(*argv))) /* Pointer checking, changed dec 6, 99 */
break;
printk("%s ", tmp);
putname(tmp); /* (frees up what getname allocated) */
}
printk("\n");
}
int init_module(void)
{
orig_execve = sys_call_table[SYS_execve];
sys_call_table[SYS_execve] = hacked_execve;
printk(KERN_INFO "execve() backdoor version 1.0.4 by Perly loaded.\n");
return(0);
}
void cleanup_module(void)
{
sys_call_table[SYS_execve] = orig_execve;
printk(KERN_INFO "execve() backdoor version 1.0.4 by Perly unloaded.\n");
}