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
| ||
|
Date: Fri, 31 Jul 2020 10:00:30 +0300 From: Leon Romanovsky <leon@...nel.org> To: Andy Shevchenko <andy.shevchenko@...il.com> Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>, Peilin Ye <yepeilin.cs@...il.com>, Santosh Shilimkar <santosh.shilimkar@...cle.com>, "David S. Miller" <davem@...emloft.net>, Jakub Kicinski <kuba@...nel.org>, Dan Carpenter <dan.carpenter@...cle.com>, Arnd Bergmann <arnd@...db.de>, "linux-kernel-mentees@...ts.linuxfoundation.org" <linux-kernel-mentees@...ts.linuxfoundation.org>, "netdev@...r.kernel.org" <netdev@...r.kernel.org>, "linux-rdma@...r.kernel.org" <linux-rdma@...r.kernel.org>, "rds-devel@....oracle.com" <rds-devel@....oracle.com>, "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org> Subject: Re: [Linux-kernel-mentees] [PATCH net] rds: Prevent kernel-infoleak in rds_notify_queue_get() On Fri, Jul 31, 2020 at 09:29:27AM +0300, Andy Shevchenko wrote: > On Friday, July 31, 2020, Greg Kroah-Hartman <gregkh@...uxfoundation.org> > wrote: > > > On Fri, Jul 31, 2020 at 07:33:06AM +0200, Greg Kroah-Hartman wrote: > > > On Fri, Jul 31, 2020 at 07:53:01AM +0300, Leon Romanovsky wrote: > > > > On Thu, Jul 30, 2020 at 03:20:26PM -0400, Peilin Ye wrote: > > > > > rds_notify_queue_get() is potentially copying uninitialized kernel > > stack > > > > > memory to userspace since the compiler may leave a 4-byte hole at > > the end > > > > > of `cmsg`. > > > > > > > > > > In 2016 we tried to fix this issue by doing `= { 0 };` on `cmsg`, > > which > > > > > unfortunately does not always initialize that 4-byte hole. Fix it by > > using > > > > > memset() instead. > > > > > > > > Of course, this is the difference between "{ 0 }" and "{}" > > initializations. > > > > > > Really? Neither will handle structures with holes in it, try it and > > > see. > > > {} is a GCC extension, but I never thought it works differently. Yes, this is GCC extension and kernel relies on them very heavily. Thanks > > > > > > > And if true, where in the C spec does it say that? > > > > thanks, > > > > greg k-h > > > > > -- > With Best Regards, > Andy Shevchenko
Powered by blists - more mailing lists