From: "Andrea Parri (Microsoft)" <parri.andrea@gmail.com>
To: linux-kernel@vger.kernel.org, linux-hyperv@vger.kernel.org
Cc: "K . Y . Srinivasan" <kys@microsoft.com>,
Haiyang Zhang <haiyangz@microsoft.com>,
Stephen Hemminger <sthemmin@microsoft.com>,
Wei Liu <wei.liu@kernel.org>,
Michael Kelley <mikelley@microsoft.com>,
Juan Vazquez <juvazq@microsoft.com>,
Saruhan Karademir <skarade@microsoft.com>,
"Andrea Parri (Microsoft)" <parri.andrea@gmail.com>
Subject: [PATCH v2 4/7] Drivers: hv: vmbus: Copy the hv_message object in vmbus_on_msg_dpc()
Date: Wed, 2 Dec 2020 10:22:11 +0100 [thread overview]
Message-ID: <20201202092214.13520-5-parri.andrea@gmail.com> (raw)
In-Reply-To: <20201202092214.13520-1-parri.andrea@gmail.com>
The hv_message object is in memory shared with the host. To prevent
an erroneous or a malicious host from 'corrupting' such object, copy
the object into private memory.
Suggested-by: Juan Vazquez <juvazq@microsoft.com>
Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com>
---
drivers/hv/vmbus_drv.c | 26 +++++++++++++++-----------
1 file changed, 15 insertions(+), 11 deletions(-)
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 0e39f1d6182e9..796202aa7f9b4 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -1054,14 +1054,24 @@ void vmbus_on_msg_dpc(unsigned long data)
{
struct hv_per_cpu_context *hv_cpu = (void *)data;
void *page_addr = hv_cpu->synic_message_page;
- struct hv_message *msg = (struct hv_message *)page_addr +
+ struct hv_message msg_copy, *msg = (struct hv_message *)page_addr +
VMBUS_MESSAGE_SINT;
- __u8 payload_size = msg->header.payload_size;
struct vmbus_channel_message_header *hdr;
enum vmbus_channel_message_type msgtype;
const struct vmbus_channel_message_table_entry *entry;
struct onmessage_work_context *ctx;
- u32 message_type = msg->header.message_type;
+ __u8 payload_size;
+ u32 message_type;
+
+ /*
+ * The hv_message object is in memory shared with the host. Prevent an
+ * erroneous or malicious host from 'corrupting' such object by copying
+ * the object to private memory.
+ */
+ memcpy(&msg_copy, msg, sizeof(struct hv_message));
+
+ payload_size = msg_copy.header.payload_size;
+ message_type = msg_copy.header.message_type;
/*
* 'enum vmbus_channel_message_type' is supposed to always be 'u32' as
@@ -1074,13 +1084,7 @@ void vmbus_on_msg_dpc(unsigned long data)
/* no msg */
return;
- /*
- * The hv_message object is in memory shared with the host. The host
- * could erroneously or maliciously modify such object. Make sure to
- * validate its fields and avoid double fetches whenever feasible.
- */
-
- hdr = (struct vmbus_channel_message_header *)msg->u.payload;
+ hdr = (struct vmbus_channel_message_header *)msg_copy.u.payload;
msgtype = hdr->msgtype;
trace_vmbus_on_msg_dpc(hdr);
@@ -1111,7 +1115,7 @@ void vmbus_on_msg_dpc(unsigned long data)
return;
INIT_WORK(&ctx->work, vmbus_onmessage_work);
- memcpy(&ctx->msg, msg, sizeof(msg->header) + payload_size);
+ memcpy(&ctx->msg, &msg_copy, sizeof(msg_copy.header) + payload_size);
/*
* The host can generate a rescind message while we
--
2.25.1
next prev parent reply other threads:[~2020-12-02 9:24 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-02 9:22 [PATCH v2 0/7] Drivers: hv: vmbus: More VMBus-hardening changes Andrea Parri (Microsoft)
2020-12-02 9:22 ` [PATCH v2 1/7] Drivers: hv: vmbus: Initialize memory to be sent to the host Andrea Parri (Microsoft)
2020-12-02 9:22 ` [PATCH v2 2/7] Drivers: hv: vmbus: Avoid double fetch of msgtype in vmbus_on_msg_dpc() Andrea Parri (Microsoft)
2020-12-02 12:22 ` Wei Liu
2020-12-02 13:37 ` Andrea Parri
2020-12-02 13:40 ` Wei Liu
2020-12-02 14:14 ` Andrea Parri
2020-12-02 9:22 ` [PATCH v2 3/7] Drivers: hv: vmbus: Avoid double fetch of payload_size " Andrea Parri (Microsoft)
2020-12-02 9:22 ` Andrea Parri (Microsoft) [this message]
2020-12-06 18:39 ` [PATCH v2 4/7] Drivers: hv: vmbus: Copy the hv_message object " Michael Kelley
2020-12-06 21:33 ` Andrea Parri
2020-12-02 9:22 ` [PATCH v2 5/7] Drivers: hv: vmbus: Avoid use-after-free in vmbus_onoffer_rescind() Andrea Parri (Microsoft)
2020-12-02 9:22 ` [PATCH v2 6/7] Drivers: hv: vmbus: Resolve race condition " Andrea Parri (Microsoft)
2020-12-02 9:22 ` [PATCH v2 7/7] Drivers: hv: vmbus: Do not allow overwriting vmbus_connection.channels[] Andrea Parri (Microsoft)
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