[PATCH 4/4] ntdll: Fixup ICMP packet id if SOCK_DGRAM fallback is used.

[Paul Gofman]

On 7/8/22 17:24, Zebediah Figura wrote:
>
> This is awfully complicated. Would it be possible to just get the 
> kernel to give us the right ID back, perhaps by adding a new socket 
> option?

I honestly have no idea how easy is to change anything in Linux kernel 
in this regard but my guess is that not easy at all. I think kernel does 
not have that ID when receiving the reply packet. It fixes up the ID in 
the sent ICMP packet. And I guess it does it for security reasons, 
probably to make sure the unprivileged user can't interfere with other 
ping users (including root) by spoofing the ICMP ID which might 
interefere with them. So given how that was done already I doubt the 
change allowing to do what we want in a straightforward way can be accepted.

>
> For that matter, I guess the same goes for the first part of the 
> series—if we could get a way to get a SOCK_RAW + IPPROTO_ICMP socket, 
> presumably one where the kernel filters out anything unsafe, that'd be 
> a lot nicer than fixing things up in Wine...
>
Same here. For some reason that was made on top of DGRAM instead of 
allowing ICMP on RAW. I guess that probably to hide raw IP header 
instead of screening / fixing up it for security reasons (and maybe 
something else to it which I not immediately know of).