linux-kernel - Re: [PATCH] kmsg: Use vmalloc instead of kmalloc when writing

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Date:	Fri, 30 Mar 2012 08:30:13 -0700
From:	Greg KH <gregkh@...uxfoundation.org>
To:	Sasha Levin <levinsasha928@...il.com>
Cc:	arnd@...db.de, viro@...iv.linux.org.uk, davej@...hat.com,
	tglx@...utronix.de, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] kmsg: Use vmalloc instead of kmalloc when writing

On Fri, Mar 30, 2012 at 01:04:27PM -0400, Sasha Levin wrote:
> There are no size checks in kmsg_write(), and we try allocating enough
> memory to store everything userspace gave us, which may be too much for
> kmalloc to allocate.

Really?  Have you seen this fail?  As only root can do this, is this
really a problem?

> One option would be to limit it to something, but we can't come up with
> a number that would make sense.
> 
> Instead, just use vmalloc so that nothing would break with large amounts
> of data.

Are you sure this will work properly?  Have you tested it with large
amounts of data?

thanks,

greg k-h
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