[PATCH v1] RDMA/nldev: Add length check for IFLA_BOND_ARP_IP_TARGET parsing

[Lin Ma]

The nla_for_each_nested parsing in function
nldev_stat_set_counter_dynamic_doit() does not check the length of the
attribute. This can lead to an out-of-attribute read and allow a
malformed nlattr (e.g., length 0) to be viewed as a 4 byte integer.

This patch adds the check based on nla_len() just as other code does,
see how bond_changelink (drivers/net/bonding/bond_netlink.c) parses
IFLA_BOND_NS_IP6_TARGET.

Fixes: 3c3c1f141639 ("RDMA/nldev: Allow optional-counter status configuration through RDMA netlink")
Signed-off-by: Lin Ma <linma@xxxxxxxxxx>
---
 drivers/infiniband/core/nldev.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/infiniband/core/nldev.c b/drivers/infiniband/core/nldev.c
index d5d3e4f0de77..74635c23b371 100644
--- a/drivers/infiniband/core/nldev.c
+++ b/drivers/infiniband/core/nldev.c
@@ -1989,6 +1989,11 @@ static int nldev_stat_set_counter_dynamic_doit(struct nlattr *tb[],
 
 	nla_for_each_nested(entry_attr, tb[RDMA_NLDEV_ATTR_STAT_HWCOUNTERS],
 			    rem) {
+		if (nla_len(entry_attr) < sizeof(index)) {
+			ret = -EINVAL;
+			goto out;
+		}
+
 		index = nla_get_u32(entry_attr);
 		if ((index >= stats->num_counters) ||
 		    !(stats->descs[index].flags & IB_STAT_FLAG_OPTIONAL)) {
-- 
2.17.1