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Commit 93714912 authored by Reshetova, Elena's avatar Reshetova, Elena Committed by David S. Miller
Browse files

net, atm: convert in_cache_entry.use 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 78893664

net/atm/mpoa_caches.c

+6 −6
Original line number Diff line number Diff line
@@ -40,7 +40,7 @@ static in_cache_entry *in_cache_get(__be32 dst_ip, 
	entry = client->in_cache;

	while (entry != NULL) {

		if (entry->ctrl_info.in_dst_ip == dst_ip) {

			atomic_inc(&entry->use);

			refcount_inc(&entry->use);

			read_unlock_bh(&client->ingress_lock);

			return entry;

		}
@@ -61,7 +61,7 @@ static in_cache_entry *in_cache_get_with_mask(__be32 dst_ip, 
	entry = client->in_cache;

	while (entry != NULL) {

		if ((entry->ctrl_info.in_dst_ip & mask) == (dst_ip & mask)) {

			atomic_inc(&entry->use);

			refcount_inc(&entry->use);

			read_unlock_bh(&client->ingress_lock);

			return entry;

		}
@@ -82,7 +82,7 @@ static in_cache_entry *in_cache_get_by_vcc(struct atm_vcc *vcc, 
	entry = client->in_cache;

	while (entry != NULL) {

		if (entry->shortcut == vcc) {

			atomic_inc(&entry->use);

			refcount_inc(&entry->use);

			read_unlock_bh(&client->ingress_lock);

			return entry;

		}
@@ -105,7 +105,7 @@ static in_cache_entry *in_cache_add_entry(__be32 dst_ip, 


	dprintk("adding an ingress entry, ip = %pI4\n", &dst_ip);



	atomic_set(&entry->use, 1);

	refcount_set(&entry->use, 1);

	dprintk("new_in_cache_entry: about to lock\n");

	write_lock_bh(&client->ingress_lock);

	entry->next = client->in_cache;
@@ -121,7 +121,7 @@ static in_cache_entry *in_cache_add_entry(__be32 dst_ip, 
	entry->count = 1;

	entry->entry_state = INGRESS_INVALID;

	entry->ctrl_info.holding_time = HOLDING_TIME_DEFAULT;

	atomic_inc(&entry->use);

	refcount_inc(&entry->use);



	write_unlock_bh(&client->ingress_lock);

	dprintk("new_in_cache_entry: unlocked\n");
@@ -178,7 +178,7 @@ static int cache_hit(in_cache_entry *entry, struct mpoa_client *mpc) 


static void in_cache_put(in_cache_entry *entry)

{

	if (atomic_dec_and_test(&entry->use)) {

	if (refcount_dec_and_test(&entry->use)) {

		memset(entry, 0, sizeof(in_cache_entry));

		kfree(entry);

	}

net/atm/mpoa_caches.h

+2 −1
Original line number Diff line number Diff line
@@ -6,6 +6,7 @@ 
#include <linux/atm.h>

#include <linux/atmdev.h>

#include <linux/atmmpc.h>

#include <linux/refcount.h>



struct mpoa_client;
@@ -25,7 +26,7 @@ typedef struct in_cache_entry { 
	struct   atm_vcc *shortcut;

	uint8_t  MPS_ctrl_ATM_addr[ATM_ESA_LEN];

	struct   in_ctrl_info ctrl_info;

	atomic_t use;

	refcount_t use;

} in_cache_entry;



struct in_cache_ops{