[PATCH v4] nbd: null check for nla_nest_start
From: Navid Emamdoost <navid.emamdoost@gmail.com>
nla_nest_start() may fail and return NULL. Insert a check and set errno
based on other call sites within the same source code.
Signed-off-by: Navid Emamdoost <navid.emamdoost@gmail.com>
Reviewed-by: Michal Kubecek <mkubecek@suse.cz>
Fixes: 47d902b90a32 ("nbd: add a status netlink command")
Signed-off-by: Kees Cook <keescook@chromium.org>
---
v3- https://lore.kernel.org/lkml/20190911164013.27364-1-navid.emamdoost@gmail.com/
Resending on behalf of the author. This seems to have gotten lost and
has been getting tracked as CVE-2019-16089 ever since. For example:
https://ubuntu.com/security/CVE-2019-16089
---
drivers/block/nbd.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 33a8f37bb6a1..b7c332528ed7 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -2433,6 +2433,12 @@ 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) {
--
2.34.1
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