Commit 6c5a1c4a authored by Reshetova, Elena's avatar Reshetova, Elena Committed by David S. Miller
Browse files

net, rds: convert rds_message.m_refcount 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 803ea850

net/rds/message.c

+6 −6
Original line number Diff line number Diff line
@@ -48,8 +48,8 @@ static unsigned int rds_exthdr_size[__RDS_EXTHDR_MAX] = { 


void rds_message_addref(struct rds_message *rm)

{

	rdsdebug("addref rm %p ref %d\n", rm, atomic_read(&rm->m_refcount));

	atomic_inc(&rm->m_refcount);

	rdsdebug("addref rm %p ref %d\n", rm, refcount_read(&rm->m_refcount));

	refcount_inc(&rm->m_refcount);

}

EXPORT_SYMBOL_GPL(rds_message_addref);
@@ -83,9 +83,9 @@ static void rds_message_purge(struct rds_message *rm) 


void rds_message_put(struct rds_message *rm)

{

	rdsdebug("put rm %p ref %d\n", rm, atomic_read(&rm->m_refcount));

	WARN(!atomic_read(&rm->m_refcount), "danger refcount zero on %p\n", rm);

	if (atomic_dec_and_test(&rm->m_refcount)) {

	rdsdebug("put rm %p ref %d\n", rm, refcount_read(&rm->m_refcount));

	WARN(!refcount_read(&rm->m_refcount), "danger refcount zero on %p\n", rm);

	if (refcount_dec_and_test(&rm->m_refcount)) {

		BUG_ON(!list_empty(&rm->m_sock_item));

		BUG_ON(!list_empty(&rm->m_conn_item));

		rds_message_purge(rm);
@@ -206,7 +206,7 @@ struct rds_message *rds_message_alloc(unsigned int extra_len, gfp_t gfp) 
	rm->m_used_sgs = 0;

	rm->m_total_sgs = extra_len / sizeof(struct scatterlist);



	atomic_set(&rm->m_refcount, 1);

	refcount_set(&rm->m_refcount, 1);

	INIT_LIST_HEAD(&rm->m_sock_item);

	INIT_LIST_HEAD(&rm->m_conn_item);

	spin_lock_init(&rm->m_rs_lock);

net/rds/rds.h

+1 −1
Original line number Diff line number Diff line
@@ -356,7 +356,7 @@ static inline u32 rds_rdma_cookie_offset(rds_rdma_cookie_t cookie) 
#define RDS_MSG_FLUSH		8



struct rds_message {

	atomic_t		m_refcount;

	refcount_t		m_refcount;

	struct list_head	m_sock_item;

	struct list_head	m_conn_item;

	struct rds_incoming	m_inc;

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