linux/kernel/seccomp.c
Eric Paris 85e7bac33b seccomp: audit abnormal end to a process due to seccomp
The audit system likes to collect information about processes that end
abnormally (SIGSEGV) as this may me useful intrusion detection information.
This patch adds audit support to collect information when seccomp forces a
task to exit because of misbehavior in a similar way.

Signed-off-by: Eric Paris <eparis@redhat.com>
2012-01-17 16:16:55 -05:00

88 lines
1.7 KiB
C

/*
* linux/kernel/seccomp.c
*
* Copyright 2004-2005 Andrea Arcangeli <andrea@cpushare.com>
*
* This defines a simple but solid secure-computing mode.
*/
#include <linux/audit.h>
#include <linux/seccomp.h>
#include <linux/sched.h>
#include <linux/compat.h>
/* #define SECCOMP_DEBUG 1 */
#define NR_SECCOMP_MODES 1
/*
* Secure computing mode 1 allows only read/write/exit/sigreturn.
* To be fully secure this must be combined with rlimit
* to limit the stack allocations too.
*/
static int mode1_syscalls[] = {
__NR_seccomp_read, __NR_seccomp_write, __NR_seccomp_exit, __NR_seccomp_sigreturn,
0, /* null terminated */
};
#ifdef CONFIG_COMPAT
static int mode1_syscalls_32[] = {
__NR_seccomp_read_32, __NR_seccomp_write_32, __NR_seccomp_exit_32, __NR_seccomp_sigreturn_32,
0, /* null terminated */
};
#endif
void __secure_computing(int this_syscall)
{
int mode = current->seccomp.mode;
int * syscall;
switch (mode) {
case 1:
syscall = mode1_syscalls;
#ifdef CONFIG_COMPAT
if (is_compat_task())
syscall = mode1_syscalls_32;
#endif
do {
if (*syscall == this_syscall)
return;
} while (*++syscall);
break;
default:
BUG();
}
#ifdef SECCOMP_DEBUG
dump_stack();
#endif
audit_seccomp(this_syscall);
do_exit(SIGKILL);
}
long prctl_get_seccomp(void)
{
return current->seccomp.mode;
}
long prctl_set_seccomp(unsigned long seccomp_mode)
{
long ret;
/* can set it only once to be even more secure */
ret = -EPERM;
if (unlikely(current->seccomp.mode))
goto out;
ret = -EINVAL;
if (seccomp_mode && seccomp_mode <= NR_SECCOMP_MODES) {
current->seccomp.mode = seccomp_mode;
set_thread_flag(TIF_SECCOMP);
#ifdef TIF_NOTSC
disable_TSC();
#endif
ret = 0;
}
out:
return ret;
}