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Revision 9c1c2b35f1d94de8325344c2777d7ee67492db3b authored by Jeff Layton on 03 April 2019, 17:16:01 UTC, committed by Ilya Dryomov on 21 January 2020, 18:02:37 UTC 
ceph: hold extra reference to r_parent over life of request
 
Currently, we just assume that it will stick around by virtue of the
submitter's reference, but later patches will allow the syscall to
return early and we can't rely on that reference at that point.

While I'm not aware of any reports of it, Xiubo pointed out that this
may fix a use-after-free.  If the wait for a reply times out or is
canceled via signal, and then the reply comes in after the syscall
returns, the client can end up trying to access r_parent without a
reference.

Take an extra reference to the inode when setting r_parent and release
it when releasing the request.

Cc: stable@vger.kernel.org
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: "Yan, Zheng" <zyan@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
1 parent def9d27
Raw File
ebt_802_3.c 
// SPDX-License-Identifier: GPL-2.0-only
/*
 * 802_3
 *
 * Author:
 * Chris Vitale csv@bluetail.com
 *
 * May 2003
 *
 */
#include <linux/module.h>
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter_bridge/ebtables.h>
#include <linux/skbuff.h>
#include <uapi/linux/netfilter_bridge/ebt_802_3.h>

static struct ebt_802_3_hdr *ebt_802_3_hdr(const struct sk_buff *skb)
{
	return (struct ebt_802_3_hdr *)skb_mac_header(skb);
}

static bool
ebt_802_3_mt(const struct sk_buff *skb, struct xt_action_param *par)
{
	const struct ebt_802_3_info *info = par->matchinfo;
	const struct ebt_802_3_hdr *hdr = ebt_802_3_hdr(skb);
	__be16 type = hdr->llc.ui.ctrl & IS_UI ? hdr->llc.ui.type : hdr->llc.ni.type;

	if (info->bitmask & EBT_802_3_SAP) {
		if (NF_INVF(info, EBT_802_3_SAP, info->sap != hdr->llc.ui.ssap))
			return false;
		if (NF_INVF(info, EBT_802_3_SAP, info->sap != hdr->llc.ui.dsap))
			return false;
	}

	if (info->bitmask & EBT_802_3_TYPE) {
		if (!(hdr->llc.ui.dsap == CHECK_TYPE && hdr->llc.ui.ssap == CHECK_TYPE))
			return false;
		if (NF_INVF(info, EBT_802_3_TYPE, info->type != type))
			return false;
	}

	return true;
}

static int ebt_802_3_mt_check(const struct xt_mtchk_param *par)
{
	const struct ebt_802_3_info *info = par->matchinfo;

	if (info->bitmask & ~EBT_802_3_MASK || info->invflags & ~EBT_802_3_MASK)
		return -EINVAL;

	return 0;
}

static struct xt_match ebt_802_3_mt_reg __read_mostly = {
	.name		= "802_3",
	.revision	= 0,
	.family		= NFPROTO_BRIDGE,
	.match		= ebt_802_3_mt,
	.checkentry	= ebt_802_3_mt_check,
	.matchsize	= sizeof(struct ebt_802_3_info),
	.me		= THIS_MODULE,
};

static int __init ebt_802_3_init(void)
{
	return xt_register_match(&ebt_802_3_mt_reg);
}

static void __exit ebt_802_3_fini(void)
{
	xt_unregister_match(&ebt_802_3_mt_reg);
}

module_init(ebt_802_3_init);
module_exit(ebt_802_3_fini);
MODULE_DESCRIPTION("Ebtables: DSAP/SSAP field and SNAP type matching");
MODULE_LICENSE("GPL");
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