From: Michael Kelley <mikelley@microsoft.com>
To: "Andrea Parri (Microsoft)" <parri.andrea@gmail.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Cc: KY Srinivasan <kys@microsoft.com>,
Haiyang Zhang <haiyangz@microsoft.com>,
Stephen Hemminger <sthemmin@microsoft.com>,
Wei Liu <wei.liu@kernel.org>,
"linux-hyperv@vger.kernel.org" <linux-hyperv@vger.kernel.org>,
Juan Vazquez <juvazq@microsoft.com>,
Saruhan Karademir <skarade@microsoft.com>
Subject: RE: [PATCH 1/6] Drivers: hv: vmbus: Initialize memory to be sent to the host
Date: Sun, 6 Dec 2020 16:59:32 +0000 [thread overview]
Message-ID: <MW2PR2101MB1052B9BAFF7876427746F596D7CF1@MW2PR2101MB1052.namprd21.prod.outlook.com> (raw)
In-Reply-To: <20201118143649.108465-2-parri.andrea@gmail.com>
From: Andrea Parri (Microsoft) <parri.andrea@gmail.com> Sent: Wednesday, November 18, 2020 6:37 AM
>
> __vmbus_open() and vmbus_teardown_gpadl() do not inizialite the memory
> for the vmbus_channel_open_channel and the vmbus_channel_gpadl_teardown
> objects they allocate respectively. These objects contain padding bytes
> and fields that are left uninitialized and that are later sent to the
> host, potentially leaking guest data. Zero initialize such fields to
> avoid leaking sensitive information to the host.
>
> Reported-by: Juan Vazquez <juvazq@microsoft.com>
> Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com>
> ---
> drivers/hv/channel.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c
> index 0d63862d65518..9aa789e5f22bb 100644
> --- a/drivers/hv/channel.c
> +++ b/drivers/hv/channel.c
> @@ -621,7 +621,7 @@ static int __vmbus_open(struct vmbus_channel *newchannel,
> goto error_clean_ring;
>
> /* Create and init the channel open message */
> - open_info = kmalloc(sizeof(*open_info) +
> + open_info = kzalloc(sizeof(*open_info) +
> sizeof(struct vmbus_channel_open_channel),
> GFP_KERNEL);
> if (!open_info) {
> @@ -748,7 +748,7 @@ int vmbus_teardown_gpadl(struct vmbus_channel *channel, u32
> gpadl_handle)
> unsigned long flags;
> int ret;
>
> - info = kmalloc(sizeof(*info) +
> + info = kzalloc(sizeof(*info) +
> sizeof(struct vmbus_channel_gpadl_teardown), GFP_KERNEL);
> if (!info)
> return -ENOMEM;
> --
> 2.25.1
This change is actually zero'ing more memory than is necessary. Only the
'msg' portion is sent to Hyper-V, so that's all that needs to be zero'ed.
But this code is not performance sensitive, and doing the tighter zero'ing
would add lines of code with no real value. So,
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
next prev parent reply other threads:[~2020-12-06 17:00 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-18 14:36 [PATCH 0/6] Drivers: hv: vmbus: More VMBus-hardening changes Andrea Parri (Microsoft)
2020-11-18 14:36 ` [PATCH 1/6] Drivers: hv: vmbus: Initialize memory to be sent to the host Andrea Parri (Microsoft)
2020-12-06 16:59 ` Michael Kelley [this message]
2020-12-06 17:54 ` Andrea Parri
2020-11-18 14:36 ` [PATCH 2/6] Drivers: hv: vmbus: Avoid double fetch of msgtype in vmbus_on_msg_dpc() Andrea Parri (Microsoft)
2020-12-06 17:10 ` Michael Kelley
2020-12-06 18:05 ` Andrea Parri
2020-11-18 14:36 ` [PATCH 3/6] Drivers: hv: vmbus: Avoid double fetch of payload_size " Andrea Parri (Microsoft)
2020-12-06 17:14 ` Michael Kelley
2020-12-06 18:20 ` Andrea Parri
2020-11-18 14:36 ` [PATCH 4/6] Drivers: hv: vmbus: Avoid use-after-free in vmbus_onoffer_rescind() Andrea Parri (Microsoft)
2020-11-24 16:26 ` Wei Liu
2020-11-24 19:54 ` Andrea Parri
2020-12-06 17:23 ` Michael Kelley
2020-11-18 14:36 ` [PATCH 5/6] Drivers: hv: vmbus: Resolve race condition " Andrea Parri (Microsoft)
2020-11-18 14:36 ` [PATCH 6/6] Drivers: hv: vmbus: Do not allow overwriting vmbus_connection.channels[] Andrea Parri (Microsoft)
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