Re: [PATCH v3] nbd_genl_status: null check for nla_nest_start

[Mark-PK Tsai]

From: Michal Kubecek 

Hi,

I found that CVE-2019-16089 still exist in upstream kernel.
Does anyone know why this patch was not merged?

[PATCH v3] nbd_genl_status: null check for nla_nest_start

[Navid Emamdoost]

nla_nest_start may fail and return NULL. The check is inserted, and
errno is selected based on other call sites within the same source code.
Update: removed extra new line.
v3 Update: added release reply, thanks to Michal Kubecek for pointing
out.

Signed-off-by: Navid Emamdoost 
---
 drivers/block/nbd.c | 6 ++
 1 file changed, 6 insertions(+)

diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index e21d2ded732b..8a9712181c2a 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -2149,6 +2149,12 @@ static int nbd_genl_status(struct sk_buff *skb, struct 
genl_info *info)
}
 
dev_list = nla_nest_start_noflag(reply, NBD_ATTR_DEVICE_LIST);
+   if (!dev_list) {
+   nlmsg_free(reply);
+   ret = -EMSGSIZE;
+   goto out;
+   }
+
if (index == -1) {
ret = idr_for_each(&nbd_index_idr, &status_cb, reply);
if (ret) {
-- 
2.17.1