2019-03-15 06:32:45

by Kangjie Lu

Subject: [PATCH] block: nbd: fix a missing check for nla_nest_start

nla_nest_start may fail and thus deserves a check.

The fix inserts such a check and exits gracefully in case it
fails.

Signed-off-by: Kangjie Lu <[email protected]>
---
drivers/block/nbd.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 7c9a949e876b..810c8c20b142 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -2099,6 +2099,10 @@ static int nbd_genl_status(struct sk_buff *skb, struct genl_info *info)
}

dev_list = nla_nest_start(reply, NBD_ATTR_DEVICE_LIST);
+ if (!dev_list) {
+ nlmsg_free(reply);
+ goto out;
+ }
if (index == -1) {
ret = idr_for_each(&nbd_index_idr, &status_cb, reply);
if (ret) {
--
2.17.1

2019-03-15 13:28:57

by Josef Bacik

Subject: Re: [PATCH] block: nbd: fix a missing check for nla_nest_start

On Fri, Mar 15, 2019 at 01:31:38AM -0500, Kangjie Lu wrote:
> nla_nest_start may fail and thus deserves a check.
>
> The fix inserts such a check and exits gracefully in case it
> fails.
>

Except it won't because we pre-reserve enough space for that attr. Subsequent
calls could fail, and those are checked properly, but this one won't. Thanks,

Josef