linux-kernel - Re: [PATCH 1/4] ozwpan: Use proper check to prevent heap overflow

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Date:	Fri, 15 May 2015 20:04:47 +0200
From:	"Jason A. Donenfeld" <Jason@...c4.com>
To:	David Laight <David.Laight@...lab.com>
Cc:	linux-kernel@...r.kernel.org, shigekatsu.tateno@...el.com,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	devel@...verdev.osuosl.org
Subject: Re: [PATCH 1/4] ozwpan: Use proper check to prevent heap overflow

On May 15, 2015 4:10 PM, "David Laight" <David.Laight@...lab.com> wrote:
> Why not just check the length. eg:
>                         unsigned int data_len = elt->length;
>                         if (data_len < sizeof(struct oz_get_desc_rsp) + 1)
>                                 break;

Sure.

> >                       u16 offs = le16_to_cpu(get_unaligned(&body->offset));
> >                       u16 total_size =
> >                               le16_to_cpu(get_unaligned(&body->total_size));
>
> Don't put variable definitions after code.
>
> You don't really want to do arithmetic on local variables that are
> smaller than a machine word (eg u8 and u16), doing so can require
> the compiler generate a lot more code.

This is code is just part of the patch context. Care to submit a
follow up patch fixing this so the maintainer can incorporate it? FYI,
this is a common occurrence throughout the driver, and a patch set
should probably be posted that systematically fixes this problem.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/