[PATCH 5.15 039/317] nbd: null check for nla_nest_start

Sasha Levin
2024-03-24T23:35:39Z

From: Navid Emamdoost <navid.emamdoost@gmail.com>

[ Upstream commit 31edf4bbe0ba27fd03ac7d87eb2ee3d2a231af6d ]

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>
Link: https://lore.kernel.org/r/20240218042534.it.206-kees@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/block/nbd.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index d379a047d4273..d12e9f1721c8e 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -2344,6 +2344,12 @@ 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) {
--
2.43.0