netdev - RE: [PATCH net 1/3] hv_netvsc: Correct the max receive buffer size

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: <CY4PR2101MB0867659182572388D7FFB34FCA300@CY4PR2101MB0867.namprd21.prod.outlook.com>
Date:   Fri, 8 Dec 2017 16:11:50 +0000
From:   Haiyang Zhang <haiyangz@...rosoft.com>
To:     Dan Carpenter <dan.carpenter@...cle.com>,
        Stephen Hemminger <stephen@...workplumber.org>
CC:     KY Srinivasan <kys@...rosoft.com>,
        Stephen Hemminger <sthemmin@...rosoft.com>,
        "devel@...uxdriverproject.org" <devel@...uxdriverproject.org>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: RE: [PATCH net 1/3] hv_netvsc: Correct the max receive buffer size



> -----Original Message-----
> From: Dan Carpenter [mailto:dan.carpenter@...cle.com]
> Sent: Friday, December 8, 2017 5:33 AM
> To: Stephen Hemminger <stephen@...workplumber.org>
> Cc: KY Srinivasan <kys@...rosoft.com>; Haiyang Zhang
> <haiyangz@...rosoft.com>; Stephen Hemminger
> <sthemmin@...rosoft.com>; devel@...uxdriverproject.org;
> netdev@...r.kernel.org
> Subject: Re: [PATCH net 1/3] hv_netvsc: Correct the max receive buffer size
> 
> On Thu, Dec 07, 2017 at 04:10:53PM -0800, Stephen Hemminger wrote:
> > From: Haiyang Zhang <haiyangz@...rosoft.com>
> >
> > It should be 31 MB on recent host versions.
> >
> > Signed-off-by: Haiyang Zhang <haiyangz@...rosoft.com>
> > Signed-off-by: Stephen Hemminger <sthemmin@...rosoft.com>
> 
> This is very vague.  What does "recent" mean in this context?  There are also
> some unrelated white space changes here which make the patch harder to
> read.
> 
> This patch kind of makes the bug fixed by patch 2 even worse because
> before the receive buffer was capped at around 16MB and now we can set
> the receive buffer to 31MB.  It might make sense to fold the two patches
> together.
> 
> Is patch 2 a memory corruption bug?  The changelog doesn't really say what
> the user visible effects of the bug are.  Basically if you make the buffer too
> small then it's a performance issue but if you make it too large what happens?
> It's not clear to me.

For NVSP v2, and earlier host, the limit is 15MB. Later hosts, the limit is 31MB.
Setting beyond it will be denied by the host, resulting the vNIC doesn't come up.

I will merge this one together with the patch 2.

Thanks,
- Haiyang