Re: [PATCH -next] x86, fs: add sys_compat_write for net/socket.c

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On 03/30/2010 10:51 AM, Florian Westphal wrote:
> On some configurations, e.g. x86_64 with 32bit userspace, netlink/xfrm
> misinterprets messages from userspace due to different structure
> layout (u64 has different alignment requirements on x86 vs. x86_64).
> 
> As long as messages are sent via sendmsg(), this could be handled via
> net/compat.c; it will set the CMSG_MSG_COMPAT flag in struct msghdr
> for compat tasks, which would allow to the xfrm_user code to detect
> when messages need compat fixups.
> 
> Unfortunately, some programs (e.g. pluto ike daemon), send netlink data
> to the kernel using write().
> 
> Thus, introduce f_ops->compat_aio_write and compat_sys_write to treat
> writes on sockets specially.
> 
> This only wires up compat_sys_write for x86/x86_64 -- at the moment this
> is only required to parse xfrm netlink messages, which happen to only
> need special treatment in case of COMPAT_FOR_U64_ALIGNMENT=y.
> 
> Setting CMSG_MSG_COMPAT depending on plain is_compat_task() in net/socket.c
> was not done due to concerns regarding the kernel doing socket
> writes in response to a user event (which might set MSG_COMPAT erronously).
> 

OK... I have to ask the question:

This only applies if you're using unpacked structures with
non-naturally-aligned objects in them.  Where to we have those, and can
we shoot the authors?

	-hpa
--
To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[Index of Archives]     [Linux Ext4 Filesystem]     [Union Filesystem]     [Filesystem Testing]     [Ceph Users]     [Ecryptfs]     [AutoFS]     [Kernel Newbies]     [Share Photos]     [Security]     [Netfilter]     [Bugtraq]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux Cachefs]     [Reiser Filesystem]     [Linux RAID]     [Samba]     [Device Mapper]     [CEPH Development]
  Powered by Linux