From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: mst@redhat.com, jasowang@redhat.com,
virtualization@lists.linux-foundation.org,
linux-kernel@vger.kernel.org, elena.reshetova@intel.com,
kirill.shutemov@linux.intel.com, Andi Kleen <ak@linux.intel.com>,
Amit Shah <amit@kernel.org>, Arnd Bergmann <arnd@arndb.de>
Subject: Re: [PATCH v1 2/6] virtio console: Harden port adding
Date: Fri, 20 Jan 2023 08:15:15 +0100 [thread overview]
Message-ID: <Y8o/g9cDZCxmL6yR@kroah.com> (raw)
In-Reply-To: <87a62eqo4h.fsf@ubik.fi.intel.com>
On Thu, Jan 19, 2023 at 10:13:18PM +0200, Alexander Shishkin wrote:
> Greg Kroah-Hartman <gregkh@linuxfoundation.org> writes:
>
> > Then you need to copy it out once, and then only deal with the local
> > copy. Otherwise you have an incomplete snapshot.
>
> Ok, would you be partial to something like this:
>
> >From 1bc9bb84004154376c2a0cf643d53257da6d1cd7 Mon Sep 17 00:00:00 2001
> From: Alexander Shishkin <alexander.shishkin@linux.intel.com>
> Date: Thu, 19 Jan 2023 21:59:02 +0200
> Subject: [PATCH] virtio console: Keep a local copy of the control structure
>
> When handling control messages, instead of peeking at the device memory
> to obtain bits of the control structure, take a snapshot of it once and
> use it instead, to prevent it from changing under us. This avoids races
> between port id validation and control event decoding, which can lead
> to, for example, a NULL dereference in port removal of a nonexistent
> port.
>
> The control structure is small enough (8 bytes) that it can be cached
> directly on the stack.
>
> Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: Arnd Bergmann <arnd@arndb.de>
> Cc: Amit Shah <amit@kernel.org>
> ---
> drivers/char/virtio_console.c | 29 +++++++++++++++--------------
> 1 file changed, 15 insertions(+), 14 deletions(-)
Yes, this looks much better, thanks!
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
next prev parent reply other threads:[~2023-01-20 7:15 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-19 13:57 [PATCH v1 0/6] Harden a few virtio bits Alexander Shishkin
2023-01-19 13:57 ` [PATCH v1 1/6] virtio console: Harden multiport against invalid host input Alexander Shishkin
2023-01-19 15:17 ` Greg Kroah-Hartman
2023-01-19 18:52 ` Alexander Shishkin
2023-01-19 19:18 ` Greg Kroah-Hartman
2023-01-19 19:34 ` Alexander Shishkin
2023-01-20 13:01 ` Michael S. Tsirkin
2023-01-20 15:51 ` Alexander Shishkin
2023-01-19 13:57 ` [PATCH v1 2/6] virtio console: Harden port adding Alexander Shishkin
2023-01-19 15:20 ` Greg Kroah-Hartman
2023-01-19 17:48 ` Alexander Shishkin
2023-01-19 18:57 ` Greg Kroah-Hartman
2023-01-19 20:13 ` Alexander Shishkin
2023-01-20 7:15 ` Greg Kroah-Hartman [this message]
2023-01-27 11:02 ` Michael S. Tsirkin
2023-01-27 11:55 ` Alexander Shishkin
2023-01-27 12:12 ` Michael S. Tsirkin
2023-01-27 12:47 ` Alexander Shishkin
2023-01-27 13:31 ` Greg Kroah-Hartman
2023-01-27 14:17 ` Alexander Shishkin
2023-01-27 14:37 ` Greg Kroah-Hartman
2023-01-27 14:46 ` Michael S. Tsirkin
2023-02-02 12:02 ` Reshetova, Elena
2023-01-27 13:52 ` Michael S. Tsirkin
2023-01-20 12:59 ` Michael S. Tsirkin
2023-01-19 13:57 ` [PATCH v1 3/6] virtio 9p: Fix an overflow Alexander Shishkin
2023-01-20 12:54 ` Michael S. Tsirkin
2023-01-20 16:29 ` Alexander Shishkin
2023-01-19 13:57 ` [PATCH v1 4/6] virtio console: Harden control message handling Alexander Shishkin
2023-01-19 15:22 ` Greg Kroah-Hartman
2023-01-20 12:45 ` Michael S. Tsirkin
2023-01-20 16:41 ` Alexander Shishkin
2023-01-27 10:58 ` Michael S. Tsirkin
2023-01-27 12:04 ` Alexander Shishkin
2023-01-19 13:57 ` [PATCH v1 5/6] virtio_net: Guard against buffer length overflow in xdp_linearize_page() Alexander Shishkin
2023-01-20 13:09 ` Michael S. Tsirkin
2023-01-19 13:57 ` [PATCH v1 6/6] virtio_ring: Prevent bounds check bypass on descriptor index Alexander Shishkin
2023-01-20 12:56 ` Michael S. Tsirkin
2023-01-20 11:55 ` [PATCH v1 0/6] Harden a few virtio bits Michael S. Tsirkin
2023-01-20 12:32 ` Alexander Shishkin
2023-01-20 12:40 ` Michael S. Tsirkin
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