[Toybox] [PATCH] losetup: Wait for ueventd to create loop device on Android

[Rob Landley]

On 8/25/22 09:52, enh wrote:
> On Thu, Aug 25, 2022 at 1:05 AM Rob Landley <rob at landley.net> wrote:
>
>     What would have made SENSE was having the netlink hotplug interface (ala
>     nlmsg_type = RTM_GETLINK) register to say it's going to send back response
>     packets with credential info for each new node (something vaguely like
>     nlmsghdr.nlmsg_flags = BLAH|NLM_F_SETCRED;) then having device node creation
>     wait for the userspace credential request the same way it waits for a userspace
>     firmware load request. You could even watchdog it where a timeout causes the
>     device creation to return error and not make the node, and if the netlink
>     program exits without properly deregistering (and a new instance doesn't
>     restart) then that's gonna time out, meaning you can't do a security attack by
>     trying to kill the daemon. (DOS sure, but show me a daemon kill that doesn't
>     deny service.) And if you fire up the netlink daemon before mounting devtmpfs
>     for the first time, it gets to annotate all the initial device node creations in
>     a cleanish way so they're never exposed without credentials.
> 
> yeah, from what i remember, that's roughly what the people who actually know
> what they're talking about said that they'd need. but that's also what they
> thought they wouldn't be able to get upstream in any realistically-spendable
> amount of time.

I don't suppose anyone ever roughed up a kernel patch?

Rob