netdev - RE: [PATCH iproute2] ip xfrm: support 64bit kernel and 32bit userspace

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: <063D6719AE5E284EB5DD2968C1650D6D1C9FE52D@AcuExch.aculab.com>
Date:	Fri, 28 Nov 2014 10:47:59 +0000
From:	David Laight <David.Laight@...LAB.COM>
To:	"'roy.qing.li@...il.com'" <roy.qing.li@...il.com>,
	"netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: RE: [PATCH iproute2] ip xfrm: support 64bit kernel and 32bit
 userspace

From: roy.qing.li@...il.com
> From: Li RongQing <roy.qing.li@...il.com>
> 
> The size of struct xfrm_userpolicy_info is 168 bytes for 64bit kernel, and
> 164 bytes for 32bit userspace because of the different alignment. and lead
> to "ip xfrm" be unable to work.
> 
> add a pad in struct xfrm_userpolicy_info, and enable it by set
> KERNEL_64_USERSPACE_32 to y
...
> diff --git a/include/linux/xfrm.h b/include/linux/xfrm.h
> index fa2ecb2..009510c 100644
> --- a/include/linux/xfrm.h
> +++ b/include/linux/xfrm.h
> @@ -407,6 +407,9 @@ struct xfrm_userpolicy_info {
>  	/* Automatically expand selector to include matching ICMP payloads. */
>  #define XFRM_POLICY_ICMP	2
>  	__u8				share;
> +#ifdef KNL_64_US_32
> +	int				pad;
> +#endif
>  };

You could add __attribute__((aligned(8))) to the structure to pad it on
all systems.

Or find the 64bit member and add __attribute__((aligned(4))) to that member
so that the 64bit version doesn't get padded.
That will make the field more expensive to access on systems that can't
do misaligned memory transfers.

	David



--
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