netdev - Re: [PATCH V2] rtnetlink: Fix problem with buffer allocation

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: <20120221.165750.2246668899195223381.davem@davemloft.net>
Date:	Tue, 21 Feb 2012 16:57:50 -0500 (EST)
From:	David Miller <davem@...emloft.net>
To:	gregory.v.rose@...el.com
Cc:	netdev@...r.kernel.org
Subject: Re: [PATCH V2] rtnetlink: Fix problem with buffer allocation

From: Greg Rose <gregory.v.rose@...el.com>
Date: Tue, 21 Feb 2012 13:51:28 -0800

> Implement a new netlink attribute type IFLA_EXT_MASK.  The mask
> is a 32 bit value that can be used to indicate to the kernel that
> certain extended ifinfo values are requested by the user application.
> At this time the only mask value defined is RTEXT_FILTER_VF to
> indicate that the user wants the ifinfo dump to send information
> about the VFs belonging to the interface.
> 
> This patch fixes a bug in which certain applications do not have
> large enough buffers to accommodate the extra information returned
> by the kernel with large numbers of SR-IOV virtual functions.
> Those applications will not send the new netlink attribute with
> the interface info dump request netlink messages so they will
> not get unexpectedly large request buffers returned by the kernel.
> 
> Modifies the rtnl_calcit function to traverse the list of net
> devices and compute the minimum buffer size that can hold the
> info dumps of all matching devices based upon the filter passed
> in via the new netlink attribute filter mask.  If no filter
> mask is sent then the buffer allocation defaults to NLMSG_GOODSIZE.
> 
> With this change it is possible to add yet to be defined netlink
> attributes to the dump request which should make it fairly extensible
> in the future.
> 
> CC: stable@...r.kernel.org
> Signed-off-by: Greg Rose <gregory.v.rose@...el.com>

Applied, with the minor change suggested by Eric in that we can
use the non-RCU list traversal in the calcit function because
we hold the RTNL always when this is invoked.

Thanks!
--
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