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From: Jason Gunthorpe <jgg@ziepe.ca>
To: Jack Leadford <leadford.jack@gmail.com>
Cc: Joe Perches <joe@perches.com>, Leon Romanovsky <leon@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Peilin Ye <yepeilin.cs@gmail.com>,
	Santosh Shilimkar <santosh.shilimkar@oracle.com>,
	"David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	Dan Carpenter <dan.carpenter@oracle.com>,
	Arnd Bergmann <arnd@arndb.de>,
	linux-kernel-mentees@lists.linuxfoundation.org,
	netdev@vger.kernel.org, linux-rdma@vger.kernel.org,
	rds-devel@oss.oracle.com, linux-kernel@vger.kernel.org
Subject: Re: [Linux-kernel-mentees] [PATCH net] rds: Prevent kernel-infoleak in rds_notify_queue_get()
Date: Fri, 14 Aug 2020 14:07:07 -0300	[thread overview]
Message-ID: <20200814170707.GV24045@ziepe.ca> (raw)
In-Reply-To: <ff066616-3bb8-b6c8-d329-7de5ab8ee982@gmail.com>

On Sat, Aug 08, 2020 at 03:57:33PM -0700, Jack Leadford wrote:
> Hello!
> 
> Thanks to Jason for getting this conversation back on track.
> 
> Yes: in general, {} or a partial initializer /will/ zero padding bits.
> 
> However, there is a bug in some versions of GCC where {} will /not/ zero
> padding bits; actually, Jason's test program in this mail
> https://lore.kernel.org/lkml/20200731143604.GF24045@ziepe.ca/
> has the right ingredients to trigger the bug, but the GCC
> versions used are outside of the bug window. :)

It seems fine, at least Godbolt doesn't show a bug with that code.

Can you share the test that does fail?

This seems like the sort of security sensitive bug that should be
addressed in gcc, not worked around in the kernel code :\

Jason

WARNING: multiple messages have this Message-ID (diff)
From: Jason Gunthorpe <jgg@ziepe.ca>
To: Jack Leadford <leadford.jack@gmail.com>
Cc: rds-devel@oss.oracle.com, Arnd Bergmann <arnd@arndb.de>,
	Leon Romanovsky <leon@kernel.org>,
	linux-rdma@vger.kernel.org,
	Santosh Shilimkar <santosh.shilimkar@oracle.com>,
	linux-kernel@vger.kernel.org,
	"David S. Miller" <davem@davemloft.net>,
	netdev@vger.kernel.org, Joe Perches <joe@perches.com>,
	Jakub Kicinski <kuba@kernel.org>,
	linux-kernel-mentees@lists.linuxfoundation.org,
	Peilin Ye <yepeilin.cs@gmail.com>,
	Dan Carpenter <dan.carpenter@oracle.com>
Subject: Re: [Linux-kernel-mentees] [PATCH net] rds: Prevent kernel-infoleak in rds_notify_queue_get()
Date: Fri, 14 Aug 2020 14:07:07 -0300	[thread overview]
Message-ID: <20200814170707.GV24045@ziepe.ca> (raw)
In-Reply-To: <ff066616-3bb8-b6c8-d329-7de5ab8ee982@gmail.com>

On Sat, Aug 08, 2020 at 03:57:33PM -0700, Jack Leadford wrote:
> Hello!
> 
> Thanks to Jason for getting this conversation back on track.
> 
> Yes: in general, {} or a partial initializer /will/ zero padding bits.
> 
> However, there is a bug in some versions of GCC where {} will /not/ zero
> padding bits; actually, Jason's test program in this mail
> https://lore.kernel.org/lkml/20200731143604.GF24045@ziepe.ca/
> has the right ingredients to trigger the bug, but the GCC
> versions used are outside of the bug window. :)

It seems fine, at least Godbolt doesn't show a bug with that code.

Can you share the test that does fail?

This seems like the sort of security sensitive bug that should be
addressed in gcc, not worked around in the kernel code :\

Jason
_______________________________________________
Linux-kernel-mentees mailing list
Linux-kernel-mentees@lists.linuxfoundation.org
https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees

  parent reply	other threads:[~2020-08-14 17:07 UTC|newest]

Thread overview: 62+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-30 19:20 [Linux-kernel-mentees] [PATCH net] rds: Prevent kernel-infoleak in rds_notify_queue_get() Peilin Ye
2020-07-30 19:20 ` Peilin Ye
2020-07-30 19:29 ` santosh.shilimkar
2020-07-30 19:29   ` santosh.shilimkar
2020-07-31  4:53 ` Leon Romanovsky
2020-07-31  4:53   ` Leon Romanovsky
2020-07-31  5:33   ` Greg Kroah-Hartman
2020-07-31  5:33     ` Greg Kroah-Hartman
2020-07-31  5:33     ` Greg Kroah-Hartman
2020-07-31  5:33       ` Greg Kroah-Hartman
2020-07-31  6:29       ` Andy Shevchenko
2020-07-31  7:00         ` Leon Romanovsky
2020-07-31  7:00           ` Leon Romanovsky
2020-07-31  7:05           ` Andy Shevchenko
2020-07-31  7:05             ` Andy Shevchenko
2020-07-31 14:04       ` Jason Gunthorpe
2020-07-31 14:04         ` Jason Gunthorpe
2020-07-31 14:21         ` Greg Kroah-Hartman
2020-07-31 14:21           ` Greg Kroah-Hartman
2020-07-31 14:36           ` Jason Gunthorpe
2020-07-31 14:36             ` Jason Gunthorpe
2020-07-31 17:19             ` Greg Kroah-Hartman
2020-07-31 17:19               ` Greg Kroah-Hartman
2020-07-31 18:27               ` Jason Gunthorpe
2020-07-31 18:27                 ` Jason Gunthorpe
2020-08-01  8:00                 ` Dan Carpenter
2020-08-01  8:00                   ` Dan Carpenter
2020-08-01 14:40                   ` Jason Gunthorpe
2020-08-01 14:40                     ` Jason Gunthorpe
2020-08-03  9:34                     ` Dan Carpenter
2020-08-03  9:34                       ` Dan Carpenter
2020-08-01  5:38               ` Leon Romanovsky
2020-08-01  5:38                 ` Leon Romanovsky
2020-08-02 22:10                 ` Jason Gunthorpe
2020-08-02 22:10                   ` Jason Gunthorpe
2020-08-02 22:23                   ` Joe Perches
2020-08-02 22:23                     ` Joe Perches
2020-08-02 22:28                     ` Jason Gunthorpe
2020-08-02 22:28                       ` Jason Gunthorpe
2020-08-02 22:45                       ` Joe Perches
2020-08-02 22:45                         ` Joe Perches
2020-08-03  4:58                         ` Leon Romanovsky
2020-08-03  4:58                           ` Leon Romanovsky
2020-08-03 23:06                         ` Jason Gunthorpe
2020-08-03 23:06                           ` Jason Gunthorpe
2020-08-08 22:57                           ` Jack Leadford
2020-08-08 22:57                             ` Jack Leadford
2020-08-09  7:04                             ` Leon Romanovsky
2020-08-09  7:04                               ` Leon Romanovsky
2020-08-14 17:07                             ` Jason Gunthorpe [this message]
2020-08-14 17:07                               ` Jason Gunthorpe
2020-07-31  6:31   ` Andy Shevchenko
2020-07-31  9:59   ` Dan Carpenter
2020-07-31  9:59     ` Dan Carpenter
2020-07-31 11:14     ` Håkon Bugge
2020-07-31 11:14       ` Håkon Bugge
2020-07-31 11:59       ` Greg Kroah-Hartman
2020-07-31 11:59         ` Greg Kroah-Hartman
2020-07-31 12:03         ` Håkon Bugge
2020-07-31 12:03           ` Håkon Bugge
2020-07-31 23:54 ` David Miller
2020-07-31 23:54   ` David Miller

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