/* String matching match for iptables
 *
 * (C) 2005 Pablo Neira Ayuso <pablo@eurodev.net>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/gfp.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/skbuff.h>
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter/xt_string.h>
#include <linux/textsearch.h>

MODULE_AUTHOR("Pablo Neira Ayuso <pablo@eurodev.net>");
MODULE_DESCRIPTION("Xtables: string-based matching");
MODULE_LICENSE("GPL");
MODULE_ALIAS("ipt_string");
MODULE_ALIAS("ip6t_string");

static bool
string_mt(const struct sk_buff *skb, struct xt_action_param *par)
{
	const struct xt_string_info *conf = par->matchinfo;
	bool invert;

	invert = conf->u.v1.flags & XT_STRING_FLAG_INVERT;

	return (skb_find_text((struct sk_buff *)skb, conf->from_offset,
			     conf->to_offset, conf->config)
			     != UINT_MAX) ^ invert;
}

#define STRING_TEXT_PRIV(m) ((struct xt_string_info *)(m))

static int string_mt_check(const struct xt_mtchk_param *par)
{
	struct xt_string_info *conf = par->matchinfo;
	struct ts_config *ts_conf;
	int flags = TS_AUTOLOAD;

	/* Damn, can't handle this case properly with iptables... */
	if (conf->from_offset > conf->to_offset)
		return -EINVAL;
	if (conf->algo[XT_STRING_MAX_ALGO_NAME_SIZE - 1] != '\0')
		return -EINVAL;
	if (conf->patlen > XT_STRING_MAX_PATTERN_SIZE)
		return -EINVAL;
	if (conf->u.v1.flags &
	    ~(XT_STRING_FLAG_IGNORECASE | XT_STRING_FLAG_INVERT))
		return -EINVAL;
	if (conf->u.v1.flags & XT_STRING_FLAG_IGNORECASE)
		flags |= TS_IGNORECASE;
	ts_conf = textsearch_prepare(conf->algo, conf->pattern, conf->patlen,
				     GFP_KERNEL, flags);
	if (IS_ERR(ts_conf))
		return PTR_ERR(ts_conf);

	conf->config = ts_conf;
	return 0;
}

static void string_mt_destroy(const struct xt_mtdtor_param *par)
{
	textsearch_destroy(STRING_TEXT_PRIV(par->matchinfo)->config);
}

static struct xt_match xt_string_mt_reg __read_mostly = {
	.name       = "string",
	.revision   = 1,
	.family     = NFPROTO_UNSPEC,
	.checkentry = string_mt_check,
	.match      = string_mt,
	.destroy    = string_mt_destroy,
	.matchsize  = sizeof(struct xt_string_info),
	.me         = THIS_MODULE,
};

static int __init string_mt_init(void)
{
	return xt_register_match(&xt_string_mt_reg);
}

static void __exit string_mt_exit(void)
{
	xt_unregister_match(&xt_string_mt_reg);
}

module_init(string_mt_init);
module_exit(string_mt_exit);
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<div class='path'>path: <a href='/cgit.cgi/linux/net-next.git/commit/?h=nds-private-remove&amp;id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>root</a>/<a href='/cgit.cgi/linux/net-next.git/commit/net?h=nds-private-remove&amp;id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>net</a>/<a href='/cgit.cgi/linux/net-next.git/commit/net/netfilter?h=nds-private-remove&amp;id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>netfilter</a>/<a href='/cgit.cgi/linux/net-next.git/commit/net/netfilter/nft_cmp.c?h=nds-private-remove&amp;id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>nft_cmp.c</a></div><div class='content'><div class='cgit-panel'><b>diff options</b><form method='get'><input type='hidden' name='h' value='nds-private-remove'/><input type='hidden' name='id' value='c8f325a59cfc718d13a50fbc746ed9b415c25e92'/><table><tr><td colspan='2'/></tr><tr><td class='label'>context:</td><td class='ctrl'><select name='context' onchange='this.form.submit();'><option value='1'>1</option><option value='2'>2</option><option value='3' selected='selected'>3</option><option value='4'>4</option><option value='5'>5</option><option value='6'>6</option><option value='7'>7</option><option value='8'>8</option><option value='9'>9</option><option value='10'>10</option><option value='15'>15</option><option value='20'>20</option><option value='25'>25</option><option value='30'>30</option><option value='35'>35</option><option value='40'>40</option></select></td></tr><tr><td class='label'>space:</td><td class='ctrl'><select name='ignorews' onchange='this.form.submit();'><option value='0' selected='selected'>include</option><option value='1'>ignore</option></select></td></tr><tr><td class='label'>mode:</td><td class='ctrl'><select name='dt' onchange='this.form.submit();'><option value='0' selected='selected'>unified</option><option value='1'>ssdiff</option><option value='2'>stat only</option></select></td></tr><tr><td/><td class='ctrl'><noscript><input type='submit' value='reload'/></noscript></td></tr></table></form></div><table summary='commit info' class='commit-info'>
<tr><th>author</th><td>Ard Biesheuvel &lt;ard.biesheuvel@linaro.org&gt;</td><td class='right'>2017-02-01 17:45:02 +0000</td></tr>
<tr><th>committer</th><td>Ingo Molnar &lt;mingo@kernel.org&gt;</td><td class='right'>2017-02-01 21:17:49 +0100</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/net/netfilter/nft_cmp.c?h=nds-private-remove&amp;id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>c8f325a59cfc718d13a50fbc746ed9b415c25e92</a> (<a href='/cgit.cgi/linux/net-next.git/patch/net/netfilter/nft_cmp.c?id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?h=nds-private-remove&amp;id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>d53fbdac9d0781e39a13b2ac6b2bd258cf3b4140</a> /<a href='/cgit.cgi/linux/net-next.git/tree/net/netfilter/nft_cmp.c?h=nds-private-remove&amp;id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>net/netfilter/nft_cmp.c</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/net/netfilter/nft_cmp.c?h=nds-private-remove&amp;id=bf29bddf0417a4783da3b24e8c9e017ac649326f'>bf29bddf0417a4783da3b24e8c9e017ac649326f</a> (<a href='/cgit.cgi/linux/net-next.git/diff/net/netfilter/nft_cmp.c?h=nds-private-remove&amp;id=c8f325a59cfc718d13a50fbc746ed9b415c25e92&amp;id2=bf29bddf0417a4783da3b24e8c9e017ac649326f'>diff</a>)</td></tr></table>
<div class='commit-subject'>efi/fdt: Avoid FDT manipulation after ExitBootServices()</div><div class='commit-msg'>Some AArch64 UEFI implementations disable the MMU in ExitBootServices(),
after which unaligned accesses to RAM are no longer supported.

Commit:

  abfb7b686a3e ("efi/libstub/arm*: Pass latest memory map to the kernel")

fixed an issue in the memory map handling of the stub FDT code, but
inadvertently created an issue with such firmware, by moving some
of the FDT manipulation to after the invocation of ExitBootServices().

Given that the stub's libfdt implementation uses the ordinary, accelerated
string functions, which rely on hardware handling of unaligned accesses,
manipulating the FDT with the MMU off may result in alignment faults.

So fix the situation by moving the update_fdt_memmap() call into the
callback function invoked by efi_exit_boot_services() right before it
calls the ExitBootServices() UEFI service (which is arguably a better
place for it anyway)

Note that disabling the MMU in ExitBootServices() is not compliant with
the UEFI spec, and carries great risk due to the fact that switching from
cached to uncached memory accesses halfway through compiler generated code
(i.e., involving a stack) can never be done in a way that is architecturally
safe.

Fixes: abfb7b686a3e ("efi/libstub/arm*: Pass latest memory map to the kernel")
Signed-off-by: Ard Biesheuvel &lt;ard.biesheuvel@linaro.org&gt;
Tested-by: Riku Voipio &lt;riku.voipio@linaro.org&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Cc: mark.rutland@arm.com
Cc: linux-efi@vger.kernel.org
Cc: matt@codeblueprint.co.uk
Cc: leif.lindholm@linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/1485971102-23330-2-git-send-email-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?h=nds-private-remove&amp;id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>Diffstat</a> (limited to 'net/netfilter/nft_cmp.c')</div><table summary='diffstat' class='diffstat'>