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Message-Id: <1561711763-24705-1-git-send-email-dag.moxnes@oracle.com>
Date: Fri, 28 Jun 2019 10:49:23 +0200
From: Dag Moxnes <dag.moxnes@...cle.com>
To: dag.moxnes@...cle.com, dledford@...hat.com, jgg@...pe.ca,
leon@...nel.org, parav@...lanox.com
Cc: linux-rdma@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH v2] RDMA/core: Fix race when resolving IP address
Use neighbour lock when copying MAC address from 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 invalid MAC address.
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.
Signed-off-by: Dag Moxnes <dag.moxnes@...cle.com>
Signed-off-by: HÃ¥kon Bugge <haakon.bugge@...cle.com>
---
v1 -> v2:
* Modified implementation to improve readability
---
drivers/infiniband/core/addr.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/drivers/infiniband/core/addr.c b/drivers/infiniband/core/addr.c
index 2f7d141598..51323ffbc5 100644
--- a/drivers/infiniband/core/addr.c
+++ b/drivers/infiniband/core/addr.c
@@ -333,11 +333,14 @@ static int dst_fetch_ha(const struct dst_entry *dst,
if (!n)
return -ENODATA;
- if (!(n->nud_state & NUD_VALID)) {
+ read_lock_bh(&n->lock);
+ if (n->nud_state & NUD_VALID) {
+ memcpy(dev_addr->dst_dev_addr, n->ha, MAX_ADDR_LEN);
+ read_unlock_bh(&n->lock);
+ } else {
+ read_unlock_bh(&n->lock);
neigh_event_send(n, NULL);
ret = -ENODATA;
- } else {
- memcpy(dev_addr->dst_dev_addr, n->ha, MAX_ADDR_LEN);
}
neigh_release(n);
--
2.20.1
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