From: Dag Moxnes dag.moxnes@oracle.com
[ Upstream commit d8d9ec7dc5abbb3f11d866e983c4984f5c2de9d6 ]
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 dag.moxnes@oracle.com Signed-off-by: Håkon Bugge haakon.bugge@oracle.com Reviewed-by: Jason Gunthorpe jgg@mellanox.com Signed-off-by: Jason Gunthorpe jgg@mellanox.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/infiniband/core/addr.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/infiniband/core/addr.c b/drivers/infiniband/core/addr.c index d0b04b0d309f..4ca31ce29a29 100644 --- a/drivers/infiniband/core/addr.c +++ b/drivers/infiniband/core/addr.c @@ -336,7 +336,7 @@ 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);