Skip to main content

Browse the archive

Revision 4de8ebeff8ddefaceeb7fc6a9b1a514fc9624509 authored by Linus Torvalds on 22 February 2016, 22:09:18 UTC, committed by Linus Torvalds on 22 February 2016, 22:09:18 UTC 
Merge tag 'trace-fixes-v4.5-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
 
Pull tracing fixes from Steven Rostedt:
 "Two more small fixes.

  One is by Yang Shi who added a READ_ONCE_NOCHECK() to the scan of the
  stack made by the stack tracer.  As the stack tracer scans the entire
  kernel stack, KASAN triggers seeing it as a "stack out of bounds"
  error.  As the scan is looking at the contents of the stack from
  parent functions.  The NOCHECK() tells KASAN that this is done on
  purpose, and is not some kind of stack overflow.

  The second fix is to the ftrace selftests, to retrieve the PID of
  executed commands from the shell with '$!' and not by parsing 'jobs'"

* tag 'trace-fixes-v4.5-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing, kasan: Silence Kasan warning in check_stack of stack_tracer
  ftracetest: Fix instance test to use proper shell command for pids
2 parent s 692b8c6 + 6e22c83
Raw File
xt_u32.c 
/*
 *	xt_u32 - kernel module to match u32 packet content
 *
 *	Original author: Don Cohen <don@isis.cs3-inc.com>
 *	(C) CC Computer Consultants GmbH, 2007
 */

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/spinlock.h>
#include <linux/skbuff.h>
#include <linux/types.h>
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter/xt_u32.h>

static bool u32_match_it(const struct xt_u32 *data,
			 const struct sk_buff *skb)
{
	const struct xt_u32_test *ct;
	unsigned int testind;
	unsigned int nnums;
	unsigned int nvals;
	unsigned int i;
	__be32 n;
	u_int32_t pos;
	u_int32_t val;
	u_int32_t at;

	/*
	 * Small example: "0 >> 28 == 4 && 8 & 0xFF0000 >> 16 = 6, 17"
	 * (=IPv4 and (TCP or UDP)). Outer loop runs over the "&&" operands.
	 */
	for (testind = 0; testind < data->ntests; ++testind) {
		ct  = &data->tests[testind];
		at  = 0;
		pos = ct->location[0].number;

		if (skb->len < 4 || pos > skb->len - 4)
			return false;

		if (skb_copy_bits(skb, pos, &n, sizeof(n)) < 0)
			BUG();
		val   = ntohl(n);
		nnums = ct->nnums;

		/* Inner loop runs over "&", "<<", ">>" and "@" operands */
		for (i = 1; i < nnums; ++i) {
			u_int32_t number = ct->location[i].number;
			switch (ct->location[i].nextop) {
			case XT_U32_AND:
				val &= number;
				break;
			case XT_U32_LEFTSH:
				val <<= number;
				break;
			case XT_U32_RIGHTSH:
				val >>= number;
				break;
			case XT_U32_AT:
				if (at + val < at)
					return false;
				at += val;
				pos = number;
				if (at + 4 < at || skb->len < at + 4 ||
				    pos > skb->len - at - 4)
					return false;

				if (skb_copy_bits(skb, at + pos, &n,
						    sizeof(n)) < 0)
					BUG();
				val = ntohl(n);
				break;
			}
		}

		/* Run over the "," and ":" operands */
		nvals = ct->nvalues;
		for (i = 0; i < nvals; ++i)
			if (ct->value[i].min <= val && val <= ct->value[i].max)
				break;

		if (i >= ct->nvalues)
			return false;
	}

	return true;
}

static bool u32_mt(const struct sk_buff *skb, struct xt_action_param *par)
{
	const struct xt_u32 *data = par->matchinfo;
	bool ret;

	ret = u32_match_it(data, skb);
	return ret ^ data->invert;
}

static struct xt_match xt_u32_mt_reg __read_mostly = {
	.name       = "u32",
	.revision   = 0,
	.family     = NFPROTO_UNSPEC,
	.match      = u32_mt,
	.matchsize  = sizeof(struct xt_u32),
	.me         = THIS_MODULE,
};

static int __init u32_mt_init(void)
{
	return xt_register_match(&xt_u32_mt_reg);
}

static void __exit u32_mt_exit(void)
{
	xt_unregister_match(&xt_u32_mt_reg);
}

module_init(u32_mt_init);
module_exit(u32_mt_exit);
MODULE_AUTHOR("Jan Engelhardt <jengelh@medozas.de>");
MODULE_DESCRIPTION("Xtables: arbitrary byte matching");
MODULE_LICENSE("GPL");
MODULE_ALIAS("ipt_u32");
MODULE_ALIAS("ip6t_u32");
back to top