[PATCH 4.9 085/116] IB/cma: Fix a race condition in iboe_addr_get_sgid()

From: Greg Kroah-Hartman
Date: Fri Jan 06 2017 - 17:33:35 EST


4.9-stable review patch. If anyone has any objections, please let me know.

------------------

From: Bart Van Assche <bart.vanassche@xxxxxxxxxxx>

commit fba332b079029c2f4f7e84c1c1cd8e3867310c90 upstream.

Code that dereferences the struct net_device ip_ptr member must be
protected with an in_dev_get() / in_dev_put() pair. Hence insert
calls to these functions.

Fixes: commit 7b85627b9f02 ("IB/cma: IBoE (RoCE) IP-based GID addressing")
Signed-off-by: Bart Van Assche <bart.vanassche@xxxxxxxxxxx>
Reviewed-by: Moni Shoua <monis@xxxxxxxxxxxx>
Cc: Or Gerlitz <ogerlitz@xxxxxxxxxxxx>
Cc: Roland Dreier <roland@xxxxxxxxxxxxxxx>
Signed-off-by: Doug Ledford <dledford@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
include/rdma/ib_addr.h | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

--- a/include/rdma/ib_addr.h
+++ b/include/rdma/ib_addr.h
@@ -205,10 +205,12 @@ static inline void iboe_addr_get_sgid(st

dev = dev_get_by_index(&init_net, dev_addr->bound_dev_if);
if (dev) {
- ip4 = (struct in_device *)dev->ip_ptr;
- if (ip4 && ip4->ifa_list && ip4->ifa_list->ifa_address)
+ ip4 = in_dev_get(dev);
+ if (ip4 && ip4->ifa_list && ip4->ifa_list->ifa_address) {
ipv6_addr_set_v4mapped(ip4->ifa_list->ifa_address,
(struct in6_addr *)gid);
+ in_dev_put(ip4);
+ }
dev_put(dev);
}
}