Re: [PATCH] wireless: wext: allocate space for NULL-terminationfor 32byte SSIDs

From: Johannes Berg
Date: Wed Dec 16 2009 - 03:56:21 EST


On Wed, 2009-12-16 at 11:58 +0800, Daniel Mack wrote:

> > If this is used in a GET, then it will be filled up to 32 bytes by the
> > get handler, and the trailing \0 your patch reserves will never be
> > copied into userspace.
>
> The problem is the GET case. The libertas driver copies ssid_len
> characters here and appends a trailing \0, which my patch caught now and
> which caused memory corruption in before.
>
> From what I've seen, libertas _does_ treat the extra data correctly
> at all places, I checked it several times now. (Btw, the %s format
> string you pointed out all use print_ssid() to properly escape all
> non-printable characters, so they're rules out, too).

Oh, ok, print_ssid() is correct of course, it gets the length.

> I'll send a patch to fix the flaw in libertas.

Thanks.

johannes

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