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: Elena Reshetova <elena.reshetova@intel.com> Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com> Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: David Windsor <dwindsor@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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				| @ -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); | ||||
| } | ||||
| 
 | ||||
|  | ||||
| @ -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 @@ jumped: | ||||
| 
 | ||||
| 		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; | ||||
| 			} | ||||
|  | ||||
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