Commit 0aeea21a authored by Reshetova, Elena's avatar Reshetova, Elena Committed by David S. Miller
Browse files

net, ipv6: convert ipv6_txoptions.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 25f4535a

include/net/ipv6.h

+4 −3
Original line number Diff line number Diff line
@@ -16,6 +16,7 @@ 
#include <linux/ipv6.h>

#include <linux/hardirq.h>

#include <linux/jhash.h>

#include <linux/refcount.h>

#include <net/if_inet6.h>

#include <net/ndisc.h>

#include <net/flow.h>
@@ -203,7 +204,7 @@ extern rwlock_t ip6_ra_lock; 
 */



struct ipv6_txoptions {

	atomic_t		refcnt;

	refcount_t		refcnt;

	/* Length of this structure */

	int			tot_len;
@@ -265,7 +266,7 @@ static inline struct ipv6_txoptions *txopt_get(const struct ipv6_pinfo *np) 
	rcu_read_lock();

	opt = rcu_dereference(np->opt);

	if (opt) {

		if (!atomic_inc_not_zero(&opt->refcnt))

		if (!refcount_inc_not_zero(&opt->refcnt))

			opt = NULL;

		else

			opt = rcu_pointer_handoff(opt);
@@ -276,7 +277,7 @@ static inline struct ipv6_txoptions *txopt_get(const struct ipv6_pinfo *np) 


static inline void txopt_put(struct ipv6_txoptions *opt)

{

	if (opt && atomic_dec_and_test(&opt->refcnt))

	if (opt && refcount_dec_and_test(&opt->refcnt))

		kfree_rcu(opt, rcu);

}

net/ipv6/exthdrs.c

+2 −2
Original line number Diff line number Diff line
@@ -971,7 +971,7 @@ ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt) 
			*((char **)&opt2->dst1opt) += dif;

		if (opt2->srcrt)

			*((char **)&opt2->srcrt) += dif;

		atomic_set(&opt2->refcnt, 1);

		refcount_set(&opt2->refcnt, 1);

	}

	return opt2;

}
@@ -1056,7 +1056,7 @@ ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt, 
		return ERR_PTR(-ENOBUFS);



	memset(opt2, 0, tot_len);

	atomic_set(&opt2->refcnt, 1);

	refcount_set(&opt2->refcnt, 1);

	opt2->tot_len = tot_len;

	p = (char *)(opt2 + 1);

net/ipv6/ipv6_sockglue.c

+1 −1
Original line number Diff line number Diff line
@@ -505,7 +505,7 @@ static int do_ipv6_setsockopt(struct sock *sk, int level, int optname, 
			break;



		memset(opt, 0, sizeof(*opt));

		atomic_set(&opt->refcnt, 1);

		refcount_set(&opt->refcnt, 1);

		opt->tot_len = sizeof(*opt) + optlen;

		retv = -EFAULT;

		if (copy_from_user(opt+1, optval, optlen))