linux-kernel - Re: [PATCHv2] ibmveth: Fix off-by-one error in ibmveth_change

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] [day] [month] [year] [list]

Message-Id: <20150423.114245.1826557896621397900.davem@davemloft.net>
Date:	Thu, 23 Apr 2015 11:42:45 -0400 (EDT)
From:	David Miller <davem@...emloft.net>
To:	david@...son.dropbear.id.au
Cc:	anton@....ibm.com, tlfalcon@...ux.vnet.ibm.com,
	michael@...erman.id.au, linux-kernel@...r.kernel.org,
	linuxppc-dev@...ts.ozlabs.org, netdev@...r.kernel.org
Subject: Re: [PATCHv2] ibmveth: Fix off-by-one error in ibmveth_change_mtu()

From: David Gibson <david@...son.dropbear.id.au>
Date: Thu, 23 Apr 2015 14:43:05 +1000

> AFAIK the PAPR document which defines the virtual device interface used by
> the ibmveth driver doesn't specify a specific maximum MTU.  So, in the
> ibmveth driver, the maximum allowed MTU is determined by the maximum
> allocated buffer size of 64k (corresponding to one page in the common case)
> minus the per-buffer overhead IBMVETH_BUFF_OH (which has value 22 for 14
> bytes of ethernet header, plus 8 bytes for an opaque handle).
> 
> This suggests a maximum allowable MTU of 65514 bytes, but in fact the
> driver only permits a maximum MTU of 65513.  This is because there is a <
> instead of an <= in ibmveth_change_mtu(), which only permits an MTU which
> is strictly smaller than the buffer size, rather than allowing the buffer
> to be completely filled.
> 
> This patch fixes the buglet.
> 
> Signed-off-by: David Gibson <david@...son.dropbear.id.au>
> Acked-by: Thomas Falcon <tlfalcon@...ux.vnet.ibm.com>

Applied, thank you.
--
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/