netdev - Re: [B.A.T.M.A.N.] [PATCH] Fix ARM BUILD_BUG

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

Message-ID: <529B9EB8.8080306@meshcoding.com>
Date:	Sun, 01 Dec 2013 21:40:24 +0100
From:	Antonio Quartulli <antonio@...hcoding.com>
To:	The list for a Better Approach To Mobile Ad-hoc
	 Networking <b.a.t.m.a.n@...ts.open-mesh.org>
CC:	netdev@...r.kernel.org, linux@....linux.org.uk
Subject: Re: [B.A.T.M.A.N.] [PATCH] Fix ARM BUILD_BUG_ON() errors with batman-adv

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

On 01/12/13 20:21, David Miller wrote:
> From: Antonio Quartulli <antonio@...hcoding.com> Date: Sun, 01 Dec
> 2013 15:28:58 +0100
> 
>> Am I wrong or this is a problem in the ARM compiler not doing
>> the right assumption? On x86 and x86_64 offset_of dest is 4, as
>> expected.
> 
> These alignment behaviors are defined by the processor ABI, there
> is no set of global rules that apply, so it behaves differently on 
> different CPUs.  What you observe is correct behavior for
> compilation on ARM processors.
> 

Ok. So, as far as I understand from your and Russell's explanation,
the only way to allow ARM to support batman-adv is to ensure that all
the _structures_ (no matter if it is a parent structure or not) sent
over the wire have a size multiple of 32bits.

If we want to fix this, I think we have to re-work a little more the
packet layout before 3.13 is released.


People using batman-adv on ARM-equipped smartphones (and similar) will
be happy about this :)



Thanks to both for the hints and for the explanations.


- -- 
Antonio Quartulli
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2.0.22 (GNU/Linux)

iEYEARECAAYFAlKbnrgACgkQpGgxIkP9cwc0ygCdHPgWg1SxUmyQOyC1xR+uNzkr
zfYAn3cEXLSMfxTCkP3CYibehI7D66tA
=AYNJ
-----END PGP SIGNATURE-----
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html