Hacker News Reader

Comment by joncfoo | Hacker News Reader

Doesn't seem to be up =\

Found the issue - a use after free in send_response() if I close the session early due to an error. Was continuing to the next bit. Put a temp fix in place, will push a proper one later.

Still seems to have an issue, but no output before the crash. Will have to do some more debugging. Thanks for the test HN!

Source is here btw: https://github.com/GSGBen/unsafehttp/blob/main/src/main.c

hotfixing httpd UAFs is peak HN spirit :)

Whoops, should be back up now. I'll have to check logs later to see why it went down.

You're going to need a bigger host to support HN traffic :)

What is it about HN that overwhelms small servers like this? It was a small static page so I wouldn't think it'd be that much load on the server itself, even for an OrangePi like this one.

Too many simultaneous connections for his router maybe? Or too much bandwidth for his internet connection?

If they are behind a NAT/ stateful firewall there is just so much connections it will handle at once. I think OpenWRT has like 16K max by default, f.ex. So for less than 16K requests by different users/IPs… each is kept for about 1 minute I think… it quickly will go down, I guess. :)

cat /proc/sys/net/netfilter/nf_conntrack_max

Should give some details.

Do you know if using the DMZ feature on most routers instead of port forwarding would get around this limit, or if there's any other way?

With OpenWRT we can increase the limit, if needed. But it's a delicate process you need to balance out carefully depending on your router. I doubled my slots and it works fine:

It's done via /etc/sysctl.conf

> net.netfilter.nf_conntrack_max=32768

Afterwards "sysctl -p" to apply/ reload the config file. But increasing blindly is a bad idea… it needs to be done with ip_conntrack_buckets in sync for proper balance (memory use, CPU usage). Best to read upon it.

But just going from 16K to 32K shouldn't be any problem for most routers these days.

I wish submitters would try using .onion sites for small static pages, for example as an alternative URL

Fewer source IPs

Reply on news.ycombinator.com