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From: Peilin Ye <yepeilin.cs@gmail.com>
To: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Arnd Bergmann <arnd@arndb.de>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	linux-kernel-mentees@lists.linuxfoundation.org,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [Linux-kernel-mentees] [PATCH v3] media/v4l2-core: Fix kernel-infoleak in video_put_user()
Date: Sun, 2 Aug 2020 12:55:35 -0400	[thread overview]
Message-ID: <20200802165535.GA270694@PWN> (raw)
In-Reply-To: <20200727131608.GD1913@kadam>

On Mon, Jul 27, 2020 at 04:16:08PM +0300, Dan Carpenter wrote:
> kernel/signal.c:3524 __do_sys_rt_sigtimedwait() warn: check that 'info' doesn't leak information (struct has a hole after 'si_code')
> kernel/signal.c:3524 __do_sys_rt_sigtimedwait() warn: check that 'info' doesn't leak information (struct has a hole after 'si_code')
> kernel/signal.c:3556 __do_sys_rt_sigtimedwait_time32() warn: check that 'info' doesn't leak information (struct has a hole after 'si_code')
> kernel/signal.c:3556 __do_sys_rt_sigtimedwait_time32() warn: check that 'info' doesn't leak information (struct has a hole after 'si_code')

I think these are safe. Before getting to copy_siginfo_to_user(), all
`info` run through:

	do_sigtimedwait()
		V
	dequeue_signal()
		V
       __dequeue_signal()
		V
	collect_signal()

Where it either gets memcpy()'d by copy_siginfo(), or memset()'d by
clear_siginfo().

The only exception is when next_signal() fails in __dequeue_signal(),
but that will cause do_sigtimedwait() to return an error, and we never
reach copy_siginfo_to_user() in such a case.

Thank you,
Peilin Ye

WARNING: multiple messages have this Message-ID (diff)
From: Peilin Ye <yepeilin.cs@gmail.com>
To: Dan Carpenter <dan.carpenter@oracle.com>
Cc: linux-kernel-mentees@lists.linuxfoundation.org,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Arnd Bergmann <arnd@arndb.de>
Subject: Re: [Linux-kernel-mentees] [PATCH v3] media/v4l2-core: Fix kernel-infoleak in video_put_user()
Date: Sun, 2 Aug 2020 12:55:35 -0400	[thread overview]
Message-ID: <20200802165535.GA270694@PWN> (raw)
In-Reply-To: <20200727131608.GD1913@kadam>

On Mon, Jul 27, 2020 at 04:16:08PM +0300, Dan Carpenter wrote:
> kernel/signal.c:3524 __do_sys_rt_sigtimedwait() warn: check that 'info' doesn't leak information (struct has a hole after 'si_code')
> kernel/signal.c:3524 __do_sys_rt_sigtimedwait() warn: check that 'info' doesn't leak information (struct has a hole after 'si_code')
> kernel/signal.c:3556 __do_sys_rt_sigtimedwait_time32() warn: check that 'info' doesn't leak information (struct has a hole after 'si_code')
> kernel/signal.c:3556 __do_sys_rt_sigtimedwait_time32() warn: check that 'info' doesn't leak information (struct has a hole after 'si_code')

I think these are safe. Before getting to copy_siginfo_to_user(), all
`info` run through:

	do_sigtimedwait()
		V
	dequeue_signal()
		V
       __dequeue_signal()
		V
	collect_signal()

Where it either gets memcpy()'d by copy_siginfo(), or memset()'d by
clear_siginfo().

The only exception is when next_signal() fails in __dequeue_signal(),
but that will cause do_sigtimedwait() to return an error, and we never
reach copy_siginfo_to_user() in such a case.

Thank you,
Peilin Ye
_______________________________________________
Linux-kernel-mentees mailing list
Linux-kernel-mentees@lists.linuxfoundation.org
https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees

  parent reply	other threads:[~2020-08-02 16:55 UTC|newest]

Thread overview: 76+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-26 16:44 [Linux-kernel-mentees] [PATCH] media/v4l2-core: Fix kernel-infoleak in video_put_user() Peilin Ye
2020-07-26 16:44 ` Peilin Ye
2020-07-26 17:30 ` Laurent Pinchart
2020-07-26 17:30   ` Laurent Pinchart
2020-07-26 18:07   ` Peilin Ye
2020-07-26 18:07     ` Peilin Ye
2020-07-26 22:08     ` Laurent Pinchart
2020-07-26 22:08       ` Laurent Pinchart
2020-07-26 22:15       ` Peilin Ye
2020-07-26 22:15         ` Peilin Ye
2020-07-26 18:12   ` Peilin Ye
2020-07-26 18:12     ` Peilin Ye
2020-07-26 22:05 ` [Linux-kernel-mentees] [PATCH v2] " Peilin Ye
2020-07-26 22:05   ` Peilin Ye
2020-07-26 22:10   ` Laurent Pinchart
2020-07-26 22:10     ` Laurent Pinchart
2020-07-26 22:16     ` Peilin Ye
2020-07-26 22:16       ` Peilin Ye
2020-07-26 22:27   ` [Linux-kernel-mentees] [PATCH v3] " Peilin Ye
2020-07-26 22:27     ` Peilin Ye
2020-07-27  7:25     ` Arnd Bergmann
2020-07-27  7:25       ` Arnd Bergmann
2020-07-27  7:56       ` Peilin Ye
2020-07-27  7:56         ` Peilin Ye
2020-07-27 13:16       ` Dan Carpenter
2020-07-27 13:16         ` Dan Carpenter
2020-07-27 14:05         ` Arnd Bergmann
2020-07-27 14:05           ` Arnd Bergmann
2020-07-27 14:14           ` Peilin Ye
2020-07-27 14:14             ` Peilin Ye
2020-07-27 14:20             ` Arnd Bergmann
2020-07-27 14:20               ` Arnd Bergmann
2020-07-27 14:46             ` Dan Carpenter
2020-07-27 14:46               ` Dan Carpenter
2020-07-27 15:30               ` Peilin Ye
2020-07-27 15:30                 ` Peilin Ye
2020-07-27 14:43           ` Dan Carpenter
2020-07-27 14:43             ` Dan Carpenter
2020-07-27 14:55             ` Arnd Bergmann
2020-07-27 14:55               ` Arnd Bergmann
2020-07-27 22:04         ` Peilin Ye
2020-07-27 22:04           ` Peilin Ye
2020-07-28  9:00           ` Arnd Bergmann
2020-07-28  9:00             ` Arnd Bergmann
2020-07-28 10:02           ` Dan Carpenter
2020-07-28 10:02             ` Dan Carpenter
2020-07-27 22:33         ` Peilin Ye
2020-07-27 22:33           ` Peilin Ye
2020-07-28  9:10           ` Arnd Bergmann
2020-07-28  9:10             ` Arnd Bergmann
2020-07-28  9:47           ` Dan Carpenter
2020-07-28  9:47             ` Dan Carpenter
2020-07-28 13:13             ` Peilin Ye
2020-07-28 13:13               ` Peilin Ye
2020-07-28 12:22         ` Linus Walleij
2020-07-28 12:22           ` Linus Walleij
2020-07-28 13:06           ` Dan Carpenter
2020-07-28 13:06             ` Dan Carpenter
2020-07-28 13:58             ` Arnd Bergmann
2020-07-28 13:58               ` Arnd Bergmann
2020-07-30  8:07               ` Bartosz Golaszewski
2020-07-30  8:07                 ` Bartosz Golaszewski
2020-07-30  8:15                 ` Arnd Bergmann
2020-07-30  8:15                   ` Arnd Bergmann
2020-07-30  8:38                   ` Andy Shevchenko
2020-07-30  8:38                     ` Andy Shevchenko
2020-07-30  9:18                     ` Arnd Bergmann
2020-07-30  9:18                       ` Arnd Bergmann
2020-07-30 11:48                       ` Andy Shevchenko
2020-07-30 11:48                         ` Andy Shevchenko
2020-07-30 13:49                         ` Arnd Bergmann
2020-07-30 13:49                           ` Arnd Bergmann
2020-08-02 16:55         ` Peilin Ye [this message]
2020-08-02 16:55           ` Peilin Ye
2020-07-27  8:00     ` [Linux-kernel-mentees] [PATCH v4] " Peilin Ye
2020-07-27  8:00       ` Peilin Ye

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