RDMA/addr: Be strict with gid size

stable inclusion
from stable-5.10.30
commit 5700c3d4abb2084aea0ff5b0ae69c32f8142db3a
bugzilla: 51791

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

[ Upstream commit d1c803a9 ]

The nla_len() is less than or equal to 16.  If it's less than 16 then end
of the "gid" buffer is uninitialized.

Fixes: ae43f828 ("IB/core: Add IP to GID netlink offload")
Link: https://lore.kernel.org/r/20210405074434.264221-1-leon@kernel.orgReported-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NMark Bloch <mbloch@nvidia.com>
Signed-off-by: NLeon Romanovsky <leonro@nvidia.com>
Signed-off-by: NJason Gunthorpe <jgg@nvidia.com>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Acked-by: N  Weilong Chen <chenweilong@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

drivers/infiniband/core/addr.c

@@ -76,7 +76,9 @@ static struct workqueue_struct *addr_wq;
 
 static const struct nla_policy ib_nl_addr_policy[LS_NLA_TYPE_MAX] = {
 	[LS_NLA_TYPE_DGID] = {.type = NLA_BINARY,
-		.len = sizeof(struct rdma_nla_ls_gid)},
+		.len = sizeof(struct rdma_nla_ls_gid),
+		.validation_type = NLA_VALIDATE_MIN,
+		.min = sizeof(struct rdma_nla_ls_gid)},
 };
 
 static inline bool ib_nl_is_good_ip_resp(const struct nlmsghdr *nlh)