Messages in this thread | | | Date | Tue, 2 Nov 2021 09:50:05 +0100 | From | Eugene Syromiatnikov <> | Subject | Re: [PATCH net-next 0/2] MCTP sockaddr padding check/initialisation fixup |
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On Tue, Nov 02, 2021 at 09:57:34AM +0800, Jeremy Kerr wrote: > Hi Eugene, > > > Padding/reserved fields necessitate appropriate checks in order to be > > usable in the future. > > We don't have a foreseeable need for extra fields here; so this is a bit > hypothetical at the moment. However, I guess there may be something that > comes up in future - was there something you have in mind?
Not really, but reality suggests that many interfaces tend to extend over time (including socket addresses, see flags in sockaddr_vm as an example), so future-proofing padding allows extending into it with minimal implementation complication, comparing to other approaches.
> The requirements for the padding bytes to be zero on sendmsg() will > break the ABI for applications that are using the interface on 5.15; > there's a small, contained set of those at the moment though, so I'm OK > to handle the updates if this patch is accepted, but we'd need to make a > call on that soon.
Yeah, I regret I have not caught it earlier.
> Setting the pad bytes to zero on recvmsg() is a good plan though, I'm > happy for that change to go in regardless.
I can split it out in case there is hesitance with regards to applying padding checks.
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