linux-kernel - Re: [PATCH v2 8/8] FS: proc, make limits writable

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Message-ID: <4ACE51A8.3030406@gmail.com>
Date:	Thu, 08 Oct 2009 22:55:04 +0200
From:	Jiri Slaby <jirislaby@...il.com>
To:	Oleg Nesterov <oleg@...hat.com>
CC:	akpm@...ux-foundation.org, mingo@...hat.com,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 8/8] FS: proc, make limits writable

On 09/04/2009 04:26 PM, Oleg Nesterov wrote:
> One small nit, just to suggest the further 9/8 cleanup,
> 
>> +static const struct file_operations proc_pid_limits_operations = {
>> +	.read		= proc_info_read,
>> +	.write		= limits_write,
>> +};
> 
> I think it makes sense to tweak proc_pid_limits() a little bit (and
> rename it), so that we can do
> 
> 	.read = limits_read,
> 	.write = limits_write
> 
> Then,
> 
>> @@ -2501,7 +2571,9 @@ static const struct pid_entry tgid_base_stuff[] = {
>> +	NOD("limits",	  S_IFREG|S_IRUSR|S_IWUSR, NULL,
>> +			&proc_pid_limits_operations,
>> +			{ .proc_read = proc_pid_limits }),
> 
> We could use
> 
> 	REG("limits", S_IRUSR|S_IWUSR, &proc_pid_limits_operations),
> 
> instead, this looks a bit cleaner to me.

Hi again, nobody picked them up yet, I waited till the end of the merge
window and now I'll repost.

Did you mean here to do the proc_info_read work (get/put task, alloc
buf, simple_read) directly in limits_read?

> And another minor nit (just in case you will re-submit this series for
> some reason). Perhaps the changelog in 6/8 should mention that we do
> not do any security checks when tsk != current (without selinux). We
> assume that either the caller is sys_setrlimit(), or the caller should
> verify it has rights to change the limits: in case of limits_write()
> we rely on ->mode = S_IRUSR|S_IWUSR.

I did it as a comment by the setrlimit. I think nobody would care about
a changelog note ;).
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