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Revision dd48c085c1cdf9446f92826f1fd451167fb6c2fd authored by Akinobu Mita on 03 August 2011, 23:21:01 UTC, committed by Linus Torvalds on 04 August 2011, 00:25:20 UTC 
fault-injection: add ability to export fault_attr in arbitrary directory
 
init_fault_attr_dentries() is used to export fault_attr via debugfs.
But it can only export it in debugfs root directory.

Per Forlin is working on mmc_fail_request which adds support to inject
data errors after a completed host transfer in MMC subsystem.

The fault_attr for mmc_fail_request should be defined per mmc host and
export it in debugfs directory per mmc host like
/sys/kernel/debug/mmc0/mmc_fail_request.

init_fault_attr_dentries() doesn't help for mmc_fail_request.  So this
introduces fault_create_debugfs_attr() which is able to create a
directory in the arbitrary directory and replace
init_fault_attr_dentries().

[akpm@linux-foundation.org: extraneous semicolon, per Randy]
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Tested-by: Per Forlin <per.forlin@linaro.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Matt Mackall <mpm@selenic.com>
Cc: Randy Dunlap <rdunlap@xenotime.net>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent f48d191
Raw File
seccomp.c 
/*
 * linux/kernel/seccomp.c
 *
 * Copyright 2004-2005  Andrea Arcangeli <andrea@cpushare.com>
 *
 * This defines a simple but solid secure-computing mode.
 */

#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
	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;
}
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