Re: CVS commit: src/sys/net

[Masanobu SAITOH <msaitoh%execsw.org@localhost>]

On 2022/10/25 14:55, Masanobu SAITOH wrote:
> 
> 
> On 2022/10/25 14:51, matthew green wrote:
>> "SAITOH Masanobu" writes:
>>> Module Name:	src
>>> Committed By:	msaitoh
>>> Date:		Mon Oct 24 07:45:44 UTC 2022
>>>
>>> Modified Files:
>>> 	src/sys/net: if_dl.h
>>>
>>> Log Message:
>>> Increase sdl_data so that more then IFNAMSIZ bytes are available.
>>>
>>>  - Increase the size of dl_data[] from 12 to 24.
>>>  - Same as OpenBSD.
>>
>> isn't this a binary compat issue?  eg, 'struct sockaddr_dl' changes,
>> and that, and things based upon it, are in user interfaces.  i had
>> a look and i believe it's a problem, but maybe i missed something.
>>
>> thanks.
>>
>>
>> .mrg.
> 
> struct dl_addr is at the end of struct sockaddr_dl.
> dl_data is at the end of struct dl_addr.
> So I think it's has no problem for old binaries.

I've roughly tested with old arp, ndp, ifconfig, ifmcstat and all /usr/tests
on a new kernel and I didn't saw any problem.

I think getifaddrs(3) has no problem. The routing message has no problem
because struct rtm_msglen has rtm_msglen and we can get the next message
using with it. I can't see any kernel data structure which has
struct sockaddr_dl foobadr[xxx] array.

One problem might be exist. An old userland program allocate buffer
with sizeof(struct sockaddr_dl), the size is smaller than the newer.
The old program might copy with memcpy(old_sized_buf, newdata, dla->sdl_len).

Should I backout the change until the COMPAT code is written?

-- 
-----------------------------------------------
                SAITOH Masanobu (msaitoh%execsw.org@localhost
                                 msaitoh%netbsd.org@localhost)