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Commit 717d1e99 authored by Reshetova, Elena's avatar Reshetova, Elena Committed by David S. Miller
Browse files

net: convert fib_rule.refcnt from atomic_t to refcount_t 



refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.

Signed-off-by: default avatarElena Reshetova <elena.reshetova@intel.com>
Signed-off-by: default avatarHans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Signed-off-by: default avatarDavid Windsor <dwindsor@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 8c9814b9

include/net/fib_rules.h

+4 −3
Original line number Diff line number Diff line
@@ -5,6 +5,7 @@ 
#include <linux/slab.h>

#include <linux/netdevice.h>

#include <linux/fib_rules.h>

#include <linux/refcount.h>

#include <net/flow.h>

#include <net/rtnetlink.h>
@@ -29,7 +30,7 @@ struct fib_rule { 
	struct fib_rule __rcu	*ctarget;

	struct net		*fr_net;



	atomic_t		refcnt;

	refcount_t		refcnt;

	u32			pref;

	int			suppress_ifgroup;

	int			suppress_prefixlen;
@@ -103,12 +104,12 @@ struct fib_rules_ops { 


static inline void fib_rule_get(struct fib_rule *rule)

{

	atomic_inc(&rule->refcnt);

	refcount_inc(&rule->refcnt);

}



static inline void fib_rule_put(struct fib_rule *rule)

{

	if (atomic_dec_and_test(&rule->refcnt))

	if (refcount_dec_and_test(&rule->refcnt))

		kfree_rcu(rule, rcu);

}

net/core/fib_rules.c

+2 −2
Original line number Diff line number Diff line
@@ -46,7 +46,7 @@ int fib_default_rule_add(struct fib_rules_ops *ops, 
	if (r == NULL)

		return -ENOMEM;



	atomic_set(&r->refcnt, 1);

	refcount_set(&r->refcnt, 1);

	r->action = FR_ACT_TO_TBL;

	r->pref = pref;

	r->table = table;
@@ -283,7 +283,7 @@ int fib_rules_lookup(struct fib_rules_ops *ops, struct flowi *fl, 


		if (err != -EAGAIN) {

			if ((arg->flags & FIB_LOOKUP_NOREF) ||

			    likely(atomic_inc_not_zero(&rule->refcnt))) {

			    likely(refcount_inc_not_zero(&rule->refcnt))) {

				arg->rule = rule;

				goto out;

			}