From d8d9ec7dc5abbb3f11d866e983c4984f5c2de9d6 Mon Sep 17 00:00:00 2001 From: Dag Moxnes Date: Tue, 9 Jul 2019 13:50:26 +0200 Subject: RDMA/core: Fix race when resolving IP address MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Use the neighbour lock when copying the MAC address from the neighbour data struct in dst_fetch_ha. When not using the lock, it is possible for the function to race with neigh_update(), causing it to copy an torn MAC address: rdma_resolve_addr() rdma_resolve_ip() addr_resolve() addr_resolve_neigh() fetch_ha() dst_fetch_ha() memcpy(dev_addr->dst_dev_addr, n->ha, MAX_ADDR_LEN) and net_ioctl() arp_ioctl() arp_rec_delete() arp_invalidate() neigh_update() __neigh_update() memcpy(&neigh->ha, lladdr, dev->addr_len) It is possible to provoke this error by calling rdma_resolve_addr() in a tight loop, while deleting the corresponding ARP entry in another tight loop. Fixes: 51d45974515c ("infiniband: addr: Consolidate code to fetch neighbour hardware address from dst.") Signed-off-by: Dag Moxnes Signed-off-by: Håkon Bugge Reviewed-by: Jason Gunthorpe Signed-off-by: Jason Gunthorpe --- drivers/infiniband/core/addr.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/infiniband/core') diff --git a/drivers/infiniband/core/addr.c b/drivers/infiniband/core/addr.c index 2f7d14159841..9b76a8fcdd24 100644 --- a/drivers/infiniband/core/addr.c +++ b/drivers/infiniband/core/addr.c @@ -337,7 +337,7 @@ static int dst_fetch_ha(const struct dst_entry *dst, neigh_event_send(n, NULL); ret = -ENODATA; } else { - memcpy(dev_addr->dst_dev_addr, n->ha, MAX_ADDR_LEN); + neigh_ha_snapshot(dev_addr->dst_dev_addr, n, dst->dev); } neigh_release(n); -- cgit v1.2.3-59-g8ed1b