Re: [PATCH] unix: escape all null bytes in abstract unix domain socket

From: Isaac Boukris
Date: Mon Oct 31 2016 - 20:57:47 EST


Hi David, thanks for looking at it.

On Mon, Oct 31, 2016 at 9:31 PM, David Miller <davem@xxxxxxxxxxxxx> wrote:
> From: Isaac Boukris <iboukris@xxxxxxxxx>
> Date: Sat, 29 Oct 2016 22:20:20 +0300
>
>> Abstract unix domain socket may embed null characters,
>> these should be translated to '@' when printed out to
>> proc the same way the null prefix is currently being
>> translated.
>>
>> This helps for tools such as netstat, lsof and the proc
>> based implementation in ss to show all the significant
>> bytes of the name (instead of getting cut at the first
>> null occurrence).
>>
>> Signed-off-by: Isaac Boukris <iboukris@xxxxxxxxx>
> ...
>> @@ -2805,14 +2805,19 @@ static int unix_seq_show(struct seq_file *seq, void *v)
>>
>> i = 0;
>> len = u->addr->len - sizeof(short);
>> - if (!UNIX_ABSTRACT(s))
>> + if (!UNIX_ABSTRACT(s)) {
>> len--;
>> - else {
>> + for ( ; i < len; i++)
>> + seq_putc(seq,
>> + u->addr->name->sun_path[i]);
>> + } else {
>> seq_putc(seq, '@');
>> i++;
>> + for ( ; i < len; i++)
>> + seq_putc(seq,
>> + u->addr->name->sun_path[i] ?:
>> + '@');
>> }
>> - for ( ; i < len; i++)
>> - seq_putc(seq, u->addr->name->sun_path[i]);
>
> I think this patch is simpler if you just do the "@" translation
> unconditionally, if it'll never trigger for the !UNIX_ABSTRACT case
> that is perfectly fine.

I've sent an updated patch.
Logically now, the 'else' block just above could be removed, but it
isn't obvious from the code that 'sun_path[0] == 0' so I left it as
is.