Commit f862e07c authored by Arnd Bergmann's avatar Arnd Bergmann Committed by David S. Miller
Browse files

rds: avoid potential stack overflow 



The rds_iw_update_cm_id function stores a large 'struct rds_sock' object
on the stack in order to pass a pair of addresses. This happens to just
fit withint the 1024 byte stack size warning limit on x86, but just
exceed that limit on ARM, which gives us this warning:

net/rds/iw_rdma.c:200:1: warning: the frame size of 1056 bytes is larger than 1024 bytes [-Wframe-larger-than=]

As the use of this large variable is basically bogus, we can rearrange
the code to not do that. Instead of passing an rds socket into
rds_iw_get_device, we now just pass the two addresses that we have
available in rds_iw_update_cm_id, and we change rds_iw_get_mr accordingly,
to create two address structures on the stack there.

Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
Acked-by: default avatarSowmini Varadhan <sowmini.varadhan@oracle.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 3a8dd971

net/rds/iw_rdma.c

+22 −18
Original line number Diff line number Diff line
@@ -88,7 +88,9 @@ static unsigned int rds_iw_unmap_fastreg_list(struct rds_iw_mr_pool *pool, 
			int *unpinned);

static void rds_iw_destroy_fastreg(struct rds_iw_mr_pool *pool, struct rds_iw_mr *ibmr);



static int rds_iw_get_device(struct rds_sock *rs, struct rds_iw_device **rds_iwdev, struct rdma_cm_id **cm_id)

static int rds_iw_get_device(struct sockaddr_in *src, struct sockaddr_in *dst,

			     struct rds_iw_device **rds_iwdev,

			     struct rdma_cm_id **cm_id)

{

	struct rds_iw_device *iwdev;

	struct rds_iw_cm_id *i_cm_id;
@@ -112,15 +114,15 @@ static int rds_iw_get_device(struct rds_sock *rs, struct rds_iw_device **rds_iwd 
				src_addr->sin_port,

				dst_addr->sin_addr.s_addr,

				dst_addr->sin_port,

				rs->rs_bound_addr,

				rs->rs_bound_port,

				rs->rs_conn_addr,

				rs->rs_conn_port);

				src->sin_addr.s_addr,

				src->sin_port,

				dst->sin_addr.s_addr,

				dst->sin_port);

#ifdef WORKING_TUPLE_DETECTION

			if (src_addr->sin_addr.s_addr == rs->rs_bound_addr &&

			    src_addr->sin_port == rs->rs_bound_port &&

			    dst_addr->sin_addr.s_addr == rs->rs_conn_addr &&

			    dst_addr->sin_port == rs->rs_conn_port) {

			if (src_addr->sin_addr.s_addr == src->sin_addr.s_addr &&

			    src_addr->sin_port == src->sin_port &&

			    dst_addr->sin_addr.s_addr == dst->sin_addr.s_addr &&

			    dst_addr->sin_port == dst->sin_port) {

#else

			/* FIXME - needs to compare the local and remote

			 * ipaddr/port tuple, but the ipaddr is the only
@@ -128,7 +130,7 @@ static int rds_iw_get_device(struct rds_sock *rs, struct rds_iw_device **rds_iwd 
			 * zero'ed.  It doesn't appear to be properly populated

			 * during connection setup...

			 */

			if (src_addr->sin_addr.s_addr == rs->rs_bound_addr) {

			if (src_addr->sin_addr.s_addr == src->sin_addr.s_addr) {

#endif

				spin_unlock_irq(&iwdev->spinlock);

				*rds_iwdev = iwdev;
@@ -180,19 +182,13 @@ int rds_iw_update_cm_id(struct rds_iw_device *rds_iwdev, struct rdma_cm_id *cm_i 
{

	struct sockaddr_in *src_addr, *dst_addr;

	struct rds_iw_device *rds_iwdev_old;

	struct rds_sock rs;

	struct rdma_cm_id *pcm_id;

	int rc;



	src_addr = (struct sockaddr_in *)&cm_id->route.addr.src_addr;

	dst_addr = (struct sockaddr_in *)&cm_id->route.addr.dst_addr;



	rs.rs_bound_addr = src_addr->sin_addr.s_addr;

	rs.rs_bound_port = src_addr->sin_port;

	rs.rs_conn_addr = dst_addr->sin_addr.s_addr;

	rs.rs_conn_port = dst_addr->sin_port;



	rc = rds_iw_get_device(&rs, &rds_iwdev_old, &pcm_id);

	rc = rds_iw_get_device(src_addr, dst_addr, &rds_iwdev_old, &pcm_id);

	if (rc)

		rds_iw_remove_cm_id(rds_iwdev, cm_id);
@@ -598,9 +594,17 @@ void *rds_iw_get_mr(struct scatterlist *sg, unsigned long nents, 
	struct rds_iw_device *rds_iwdev;

	struct rds_iw_mr *ibmr = NULL;

	struct rdma_cm_id *cm_id;

	struct sockaddr_in src = {

		.sin_addr.s_addr = rs->rs_bound_addr,

		.sin_port = rs->rs_bound_port,

	};

	struct sockaddr_in dst = {

		.sin_addr.s_addr = rs->rs_conn_addr,

		.sin_port = rs->rs_conn_port,

	};

	int ret;



	ret = rds_iw_get_device(rs, &rds_iwdev, &cm_id);

	ret = rds_iw_get_device(&src, &dst, &rds_iwdev, &cm_id);

	if (ret || !cm_id) {

		ret = -ENODEV;

		goto out;

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