| Message ID | 20230323193032.28483-1-mkoutny@suse.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [RESEND,v3] nbd_genl_status: null check for nla_nest_start | expand |
On 3/23/23 1:30 PM, Michal Koutný wrote: > From: Navid Emamdoost <navid.emamdoost@gmail.com> > > 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. Josef? Looks straight forward to me, though it's not clear (to me) how this can be triggered and hence how important it is. > Signed-off-by: Navid Emamdoost <navid.emamdoost@gmail.com> > Reviewed-by: Michal Kubecek <mkubecek@suse.cz> > Link: https://lore.kernel.org/r/20190911164013.27364-1-navid.emamdoost@gmail.com/ > --- > > I'm resending the patch because there was apparent consensus of its > inclusion and it seems it was only overlooked. Some people may care > about this because of CVE-2019-16089. Anyone can file a CVE, and in fact they are often filed as some kind of silly trophy. Whether a CVE exists or not has ZERO bearing on whether a bug is worth fixing. So please don't mix CVEs into any of this, they don't matter one bit. Never have, and never will. What's important is how the bug can be triggered.
Thanks for the reply. On Thu, Mar 23, 2023 at 04:51:17PM -0600, Jens Axboe <axboe@kernel.dk> wrote: > So please don't mix CVEs into any of this, they don't matter one bit. Do not shoot the messenger. (But I'll refrain from that numeric reference to disincentivize such trophy collecting.) > Never have, and never will. What's important is how the bug can be > triggered. From my perspective it's pragmatic better-safe-than-sorry -- a proof may be conceived that rules out any triggering condition, it's less work to put the guard in though. My .02€, Michal
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index 592cfa8b765a..109dccd9a515 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -2394,6 +2394,12 @@ 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) {