/*
 * netsniff-ng - the packet sniffing beast
 * Copyright 2012 Markus Amend <markus@netsniff-ng.org>, Deutsche Flugsicherung GmbH
 * Subject to the GPL, version 2.
 *
 * IPv6 Destination Options Header described in RFC2460
 */

#include <stdio.h>
#include <stdint.h>
#include <netinet/in.h>    /* for ntohs() */

#include "proto.h"
#include "dissector_eth.h"
#include "built_in.h"
#include "pkt_buff.h"

struct dest_optshdr {
	uint8_t h_next_header;
	uint8_t hdr_len;
} __packed;


static void dissect_opt_dest(struct pkt_buff *pkt __maybe_unused,
			     ssize_t *opt_len)
{
	/* Have to been upgraded.
	 * http://tools.ietf.org/html/rfc2460#section-4.2
	 * Look also for proto_ipv6_hop_by_hop.h, it needs
	 * dissect_opt(), too.
	 */
	if (*opt_len)
		tprintf(", Option(s) recognized ");

	/* If adding dissector reduce opt_len for each using of pkt_pull
	 * to the same size.
	 */
}

static void dest_opts(struct pkt_buff *pkt)
{
	uint16_t hdr_ext_len;
	ssize_t opt_len;
	struct dest_optshdr *dest_ops;

	dest_ops = (struct dest_optshdr *) pkt_pull(pkt, sizeof(*dest_ops));
	if (dest_ops == NULL)
		return;

	/* Total Header Length in Bytes */
	hdr_ext_len = (dest_ops->hdr_len + 1) * 8;
	/* Options length in Bytes */
	opt_len = hdr_ext_len - sizeof(*dest_ops);

	tprintf("\t [ Destination Options ");
	tprintf("NextHdr (%u), ", dest_ops->h_next_header);
	if (opt_len > pkt_len(pkt) || opt_len < 0) {
	      tprintf("HdrExtLen (%u, %u Bytes, %s)", dest_ops->hdr_len,
		    hdr_ext_len, colorize_start_full(black, red)
		    "invalid" colorize_end());
		    return;
	}
	tprintf("HdrExtLen (%u, %u Bytes)", dest_ops->hdr_len,
		hdr_ext_len);

	dissect_opt_dest(pkt, &opt_len);

	tprintf(" ]\n");

	pkt_pull(pkt, opt_len);
	pkt_set_proto(pkt, &eth_lay3, dest_ops->h_next_header);
}

static void dest_opts_less(struct pkt_buff *pkt)
{
	uint16_t hdr_ext_len;
	ssize_t opt_len;
	struct dest_optshdr *dest_ops;

	dest_ops = (struct dest_optshdr *) pkt_pull(pkt, sizeof(*dest_ops));
	if (dest_ops == NULL)
		return;

	/* Total Header Length in Bytes */
	hdr_ext_len = (dest_ops->hdr_len + 1) * 8;
	/* Options length in Bytes */
	opt_len = hdr_ext_len - sizeof(*dest_ops);
	if (opt_len > pkt_len(pkt) || opt_len < 0)
		return;

	tprintf(" Dest Ops");

	pkt_pull(pkt, opt_len);
	pkt_set_proto(pkt, &eth_lay3, dest_ops->h_next_header);
}

struct protocol ipv6_dest_opts_ops = {
	.key = 0x3C,
	.print_full = dest_opts,
	.print_less = dest_opts_less,
};
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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/include?h=nds-private-remove&amp;id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>include</a>/<a href='/cgit.cgi/linux/net-next.git/commit/include/soc?h=nds-private-remove&amp;id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>soc</a>/<a href='/cgit.cgi/linux/net-next.git/commit/include/soc/arc?h=nds-private-remove&amp;id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>arc</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/include/soc/arc?h=nds-private-remove&amp;id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>c8f325a59cfc718d13a50fbc746ed9b415c25e92</a> (<a href='/cgit.cgi/linux/net-next.git/patch/include/soc/arc?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/include/soc/arc?h=nds-private-remove&amp;id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>include/soc/arc</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/include/soc/arc?h=nds-private-remove&amp;id=bf29bddf0417a4783da3b24e8c9e017ac649326f'>bf29bddf0417a4783da3b24e8c9e017ac649326f</a> (<a href='/cgit.cgi/linux/net-next.git/diff/include/soc/arc?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 'include/soc/arc')</div><table summary='diffstat' class='diffstat'>