lkml.org 
[lkml]   [2019]   [Jun]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH] RDMA/core: Fix race when resolving IP address
Date
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@oracle.com>
Change-Id: I3c5f982b304457f0a83ea7def2fac70315ed38b4
---
drivers/infiniband/core/addr.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/infiniband/core/addr.c b/drivers/infiniband/core/addr.c
index 2f7d141598..e4945fd1bb 100644
--- a/drivers/infiniband/core/addr.c
+++ b/drivers/infiniband/core/addr.c
@@ -333,12 +333,16 @@ static int dst_fetch_ha(const struct dst_entry *dst,
if (!n)
return -ENODATA;

+ read_lock_bh(&n->lock)
if (!(n->nud_state & NUD_VALID)) {
- neigh_event_send(n, NULL);
ret = -ENODATA;
} else {
memcpy(dev_addr->dst_dev_addr, n->ha, MAX_ADDR_LEN);
}
+ read_unlock_bh(&n->lock);
+
+ if (ret)
+ neigh_event_send(n, NULL);

neigh_release(n);

--
2.20.1
\
 
 \ /
  Last update: 2019-06-21 16:09    [W:0.055 / U:3.332 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site