* [PATCH v6 1/3] Drivers: hv: vmbus: Add vmbus_requestor data structure for VMBus hardening
2020-07-22 22:39 [PATCH v6 0/3] Drivers: hv: vmbus: vmbus_requestor data structure for VMBus hardening Andres Beltran
@ 2020-07-22 22:39 ` Andres Beltran
2020-07-23 1:24 ` Michael Kelley
2020-07-22 22:39 ` [PATCH v6 2/3] scsi: storvsc: Use vmbus_requestor to generate transaction IDs " Andres Beltran
2020-07-22 22:39 ` [PATCH v6 3/3] hv_netvsc: " Andres Beltran
2 siblings, 1 reply; 6+ messages in thread
From: Andres Beltran @ 2020-07-22 22:39 UTC (permalink / raw)
To: kys, haiyangz, sthemmin, wei.liu
Cc: linux-hyperv, linux-kernel, mikelley, parri.andrea, Andres Beltran
Currently, VMbus drivers use pointers into guest memory as request IDs
for interactions with Hyper-V. To be more robust in the face of errors
or malicious behavior from a compromised Hyper-V, avoid exposing
guest memory addresses to Hyper-V. Also avoid Hyper-V giving back a
bad request ID that is then treated as the address of a guest data
structure with no validation. Instead, encapsulate these memory
addresses and provide small integers as request IDs.
Signed-off-by: Andres Beltran <lkmlabelt@gmail.com>
---
Changes in v6:
- Offset request IDs by 1 keeping the original initialization
code.
Changes in v5:
- Add support for unsolicited messages sent by the host with a
request ID of 0.
Changes in v4:
- Use channel->rqstor_size to check if rqstor has been
initialized.
Changes in v3:
- Check that requestor has been initialized in
vmbus_next_request_id() and vmbus_request_addr().
Changes in v2:
- Get rid of "rqstor" variable in __vmbus_open().
drivers/hv/channel.c | 170 +++++++++++++++++++++++++++++++++++++++++
include/linux/hyperv.h | 21 +++++
2 files changed, 191 insertions(+)
diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c
index 3ebda7707e46..f12c388daad2 100644
--- a/drivers/hv/channel.c
+++ b/drivers/hv/channel.c
@@ -112,6 +112,70 @@ int vmbus_alloc_ring(struct vmbus_channel *newchannel,
}
EXPORT_SYMBOL_GPL(vmbus_alloc_ring);
+/**
+ * request_arr_init - Allocates memory for the requestor array. Each slot
+ * keeps track of the next available slot in the array. Initially, each
+ * slot points to the next one (as in a Linked List). The last slot
+ * does not point to anything, so its value is U64_MAX by default.
+ * @size The size of the array
+ */
+static u64 *request_arr_init(u32 size)
+{
+ int i;
+ u64 *req_arr;
+
+ req_arr = kcalloc(size, sizeof(u64), GFP_KERNEL);
+ if (!req_arr)
+ return NULL;
+
+ for (i = 0; i < size - 1; i++)
+ req_arr[i] = i + 1;
+
+ /* Last slot (no more available slots) */
+ req_arr[i] = U64_MAX;
+
+ return req_arr;
+}
+
+/*
+ * vmbus_alloc_requestor - Initializes @rqstor's fields.
+ * Index 0 is the first free slot
+ * @size: Size of the requestor array
+ */
+static int vmbus_alloc_requestor(struct vmbus_requestor *rqstor, u32 size)
+{
+ u64 *rqst_arr;
+ unsigned long *bitmap;
+
+ rqst_arr = request_arr_init(size);
+ if (!rqst_arr)
+ return -ENOMEM;
+
+ bitmap = bitmap_zalloc(size, GFP_KERNEL);
+ if (!bitmap) {
+ kfree(rqst_arr);
+ return -ENOMEM;
+ }
+
+ rqstor->req_arr = rqst_arr;
+ rqstor->req_bitmap = bitmap;
+ rqstor->size = size;
+ rqstor->next_request_id = 0;
+ spin_lock_init(&rqstor->req_lock);
+
+ return 0;
+}
+
+/*
+ * vmbus_free_requestor - Frees memory allocated for @rqstor
+ * @rqstor: Pointer to the requestor struct
+ */
+static void vmbus_free_requestor(struct vmbus_requestor *rqstor)
+{
+ kfree(rqstor->req_arr);
+ bitmap_free(rqstor->req_bitmap);
+}
+
static int __vmbus_open(struct vmbus_channel *newchannel,
void *userdata, u32 userdatalen,
void (*onchannelcallback)(void *context), void *context)
@@ -132,6 +196,12 @@ static int __vmbus_open(struct vmbus_channel *newchannel,
if (newchannel->state != CHANNEL_OPEN_STATE)
return -EINVAL;
+ /* Create and init requestor */
+ if (newchannel->rqstor_size) {
+ if (vmbus_alloc_requestor(&newchannel->requestor, newchannel->rqstor_size))
+ return -ENOMEM;
+ }
+
newchannel->state = CHANNEL_OPENING_STATE;
newchannel->onchannel_callback = onchannelcallback;
newchannel->channel_callback_context = context;
@@ -228,6 +298,7 @@ static int __vmbus_open(struct vmbus_channel *newchannel,
error_clean_ring:
hv_ringbuffer_cleanup(&newchannel->outbound);
hv_ringbuffer_cleanup(&newchannel->inbound);
+ vmbus_free_requestor(&newchannel->requestor);
newchannel->state = CHANNEL_OPEN_STATE;
return err;
}
@@ -703,6 +774,9 @@ static int vmbus_close_internal(struct vmbus_channel *channel)
channel->ringbuffer_gpadlhandle = 0;
}
+ if (!ret)
+ vmbus_free_requestor(&channel->requestor);
+
return ret;
}
@@ -937,3 +1011,99 @@ int vmbus_recvpacket_raw(struct vmbus_channel *channel, void *buffer,
buffer_actual_len, requestid, true);
}
EXPORT_SYMBOL_GPL(vmbus_recvpacket_raw);
+
+/*
+ * vmbus_next_request_id - Returns a new request id. It is also
+ * the index at which the guest memory address is stored.
+ * Uses a spin lock to avoid race conditions.
+ * @rqstor: Pointer to the requestor struct
+ * @rqst_add: Guest memory address to be stored in the array
+ */
+u64 vmbus_next_request_id(struct vmbus_requestor *rqstor, u64 rqst_addr)
+{
+ unsigned long flags;
+ u64 current_id;
+ const struct vmbus_channel *channel =
+ container_of(rqstor, const struct vmbus_channel, requestor);
+
+ /* Check rqstor has been initialized */
+ if (!channel->rqstor_size)
+ return VMBUS_RQST_ERROR;
+
+ spin_lock_irqsave(&rqstor->req_lock, flags);
+ current_id = rqstor->next_request_id;
+
+ /* Requestor array is full */
+ if (current_id >= rqstor->size) {
+ current_id = VMBUS_RQST_ERROR;
+ goto exit;
+ }
+
+ rqstor->next_request_id = rqstor->req_arr[current_id];
+ rqstor->req_arr[current_id] = rqst_addr;
+
+ /* The already held spin lock provides atomicity */
+ bitmap_set(rqstor->req_bitmap, current_id, 1);
+
+exit:
+ spin_unlock_irqrestore(&rqstor->req_lock, flags);
+
+ /*
+ * Cannot return an ID of 0, which is reserved for an unsolicited
+ * message from Hyper-V.
+ */
+ return current_id + 1;
+}
+EXPORT_SYMBOL_GPL(vmbus_next_request_id);
+
+/*
+ * vmbus_request_addr - Returns the memory address stored at @trans_id
+ * in @rqstor. Uses a spin lock to avoid race conditions.
+ * @rqstor: Pointer to the requestor struct
+ * @trans_id: Request id sent back from Hyper-V. Becomes the requestor's
+ * next request id.
+ */
+u64 vmbus_request_addr(struct vmbus_requestor *rqstor, u64 trans_id)
+{
+ unsigned long flags;
+ u64 req_addr;
+ const struct vmbus_channel *channel =
+ container_of(rqstor, const struct vmbus_channel, requestor);
+
+ /* Check rqstor has been initialized */
+ if (!channel->rqstor_size)
+ return VMBUS_RQST_ERROR;
+
+ /* Hyper-V can send an unsolicited message with ID of 0 */
+ if (!trans_id)
+ return trans_id;
+
+ spin_lock_irqsave(&rqstor->req_lock, flags);
+
+ /* Data corresponding to trans_id is stored at trans_id - 1 */
+ trans_id--;
+
+ /* Invalid trans_id */
+ if (trans_id >= rqstor->size) {
+ req_addr = VMBUS_RQST_ERROR;
+ goto exit;
+ }
+
+ /* Invalid trans_id: empty slot */
+ if (!test_bit(trans_id, rqstor->req_bitmap)) {
+ req_addr = VMBUS_RQST_ERROR;
+ goto exit;
+ }
+
+ req_addr = rqstor->req_arr[trans_id];
+ rqstor->req_arr[trans_id] = rqstor->next_request_id;
+ rqstor->next_request_id = trans_id;
+
+ /* The already held spin lock provides atomicity */
+ bitmap_clear(rqstor->req_bitmap, trans_id, 1);
+
+exit:
+ spin_unlock_irqrestore(&rqstor->req_lock, flags);
+ return req_addr;
+}
+EXPORT_SYMBOL_GPL(vmbus_request_addr);
diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index 38100e80360a..c509d20ab7db 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -716,6 +716,21 @@ enum vmbus_device_type {
HV_UNKNOWN,
};
+/*
+ * Provides request ids for VMBus. Encapsulates guest memory
+ * addresses and stores the next available slot in req_arr
+ * to generate new ids in constant time.
+ */
+struct vmbus_requestor {
+ u64 *req_arr;
+ unsigned long *req_bitmap; /* is a given slot available? */
+ u32 size;
+ u64 next_request_id;
+ spinlock_t req_lock; /* provides atomicity */
+};
+
+#define VMBUS_RQST_ERROR U64_MAX
+
struct vmbus_device {
u16 dev_type;
guid_t guid;
@@ -940,8 +955,14 @@ struct vmbus_channel {
u32 fuzz_testing_interrupt_delay;
u32 fuzz_testing_message_delay;
+ /* request/transaction ids for VMBus */
+ struct vmbus_requestor requestor;
+ u32 rqstor_size;
};
+u64 vmbus_next_request_id(struct vmbus_requestor *rqstor, u64 rqst_addr);
+u64 vmbus_request_addr(struct vmbus_requestor *rqstor, u64 trans_id);
+
static inline bool is_hvsock_channel(const struct vmbus_channel *c)
{
return !!(c->offermsg.offer.chn_flags &
--
2.25.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* RE: [PATCH v6 1/3] Drivers: hv: vmbus: Add vmbus_requestor data structure for VMBus hardening
2020-07-22 22:39 ` [PATCH v6 1/3] Drivers: hv: vmbus: Add " Andres Beltran
@ 2020-07-23 1:24 ` Michael Kelley
2020-07-23 17:58 ` Wei Liu
0 siblings, 1 reply; 6+ messages in thread
From: Michael Kelley @ 2020-07-23 1:24 UTC (permalink / raw)
To: Andres Beltran, KY Srinivasan, Haiyang Zhang, Stephen Hemminger, wei.liu
Cc: linux-hyperv, linux-kernel, parri.andrea
From: Andres Beltran <lkmlabelt@gmail.com> Sent: Wednesday, July 22, 2020 3:39 PM
>
> Currently, VMbus drivers use pointers into guest memory as request IDs
> for interactions with Hyper-V. To be more robust in the face of errors
> or malicious behavior from a compromised Hyper-V, avoid exposing
> guest memory addresses to Hyper-V. Also avoid Hyper-V giving back a
> bad request ID that is then treated as the address of a guest data
> structure with no validation. Instead, encapsulate these memory
> addresses and provide small integers as request IDs.
>
> Signed-off-by: Andres Beltran <lkmlabelt@gmail.com>
> ---
> Changes in v6:
> - Offset request IDs by 1 keeping the original initialization
> code.
> Changes in v5:
> - Add support for unsolicited messages sent by the host with a
> request ID of 0.
> Changes in v4:
> - Use channel->rqstor_size to check if rqstor has been
> initialized.
> Changes in v3:
> - Check that requestor has been initialized in
> vmbus_next_request_id() and vmbus_request_addr().
> Changes in v2:
> - Get rid of "rqstor" variable in __vmbus_open().
>
> drivers/hv/channel.c | 170 +++++++++++++++++++++++++++++++++++++++++
> include/linux/hyperv.h | 21 +++++
> 2 files changed, 191 insertions(+)
Tested-by: Michael Kelley <mikelley@microsoft.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v6 1/3] Drivers: hv: vmbus: Add vmbus_requestor data structure for VMBus hardening
2020-07-23 1:24 ` Michael Kelley
@ 2020-07-23 17:58 ` Wei Liu
0 siblings, 0 replies; 6+ messages in thread
From: Wei Liu @ 2020-07-23 17:58 UTC (permalink / raw)
To: Michael Kelley
Cc: Andres Beltran, KY Srinivasan, Haiyang Zhang, Stephen Hemminger,
wei.liu, linux-hyperv, linux-kernel, parri.andrea
On Thu, Jul 23, 2020 at 01:24:03AM +0000, Michael Kelley wrote:
> From: Andres Beltran <lkmlabelt@gmail.com> Sent: Wednesday, July 22, 2020 3:39 PM
> >
> > Currently, VMbus drivers use pointers into guest memory as request IDs
> > for interactions with Hyper-V. To be more robust in the face of errors
> > or malicious behavior from a compromised Hyper-V, avoid exposing
> > guest memory addresses to Hyper-V. Also avoid Hyper-V giving back a
> > bad request ID that is then treated as the address of a guest data
> > structure with no validation. Instead, encapsulate these memory
> > addresses and provide small integers as request IDs.
> >
> > Signed-off-by: Andres Beltran <lkmlabelt@gmail.com>
> > ---
> > Changes in v6:
> > - Offset request IDs by 1 keeping the original initialization
> > code.
> > Changes in v5:
> > - Add support for unsolicited messages sent by the host with a
> > request ID of 0.
> > Changes in v4:
> > - Use channel->rqstor_size to check if rqstor has been
> > initialized.
> > Changes in v3:
> > - Check that requestor has been initialized in
> > vmbus_next_request_id() and vmbus_request_addr().
> > Changes in v2:
> > - Get rid of "rqstor" variable in __vmbus_open().
> >
> > drivers/hv/channel.c | 170 +++++++++++++++++++++++++++++++++++++++++
> > include/linux/hyperv.h | 21 +++++
> > 2 files changed, 191 insertions(+)
>
> Tested-by: Michael Kelley <mikelley@microsoft.com>
> Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Applied to hyperv-next. Thanks.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH v6 2/3] scsi: storvsc: Use vmbus_requestor to generate transaction IDs for VMBus hardening
2020-07-22 22:39 [PATCH v6 0/3] Drivers: hv: vmbus: vmbus_requestor data structure for VMBus hardening Andres Beltran
2020-07-22 22:39 ` [PATCH v6 1/3] Drivers: hv: vmbus: Add " Andres Beltran
@ 2020-07-22 22:39 ` Andres Beltran
2020-07-22 22:39 ` [PATCH v6 3/3] hv_netvsc: " Andres Beltran
2 siblings, 0 replies; 6+ messages in thread
From: Andres Beltran @ 2020-07-22 22:39 UTC (permalink / raw)
To: kys, haiyangz, sthemmin, wei.liu
Cc: linux-hyperv, linux-kernel, mikelley, parri.andrea,
Andres Beltran, James E.J. Bottomley, Martin K. Petersen,
linux-scsi
Currently, pointers to guest memory are passed to Hyper-V as
transaction IDs in storvsc. In the face of errors or malicious
behavior in Hyper-V, storvsc should not expose or trust the transaction
IDs returned by Hyper-V to be valid guest memory addresses. Instead,
use small integers generated by vmbus_requestor as requests
(transaction) IDs.
Cc: "James E.J. Bottomley" <jejb@linux.ibm.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: linux-scsi@vger.kernel.org
Signed-off-by: Andres Beltran <lkmlabelt@gmail.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Andrea Parri <parri.andrea@gmail.com>
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20200701001221.2540-3-lkmlabelt@gmail.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
---
Changes in v2:
- Add casts to unsigned long to fix warnings on 32bit.
drivers/scsi/storvsc_drv.c | 85 +++++++++++++++++++++++++++++++++-----
1 file changed, 74 insertions(+), 11 deletions(-)
diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c
index 624467e2590a..6d2df1f0fe6d 100644
--- a/drivers/scsi/storvsc_drv.c
+++ b/drivers/scsi/storvsc_drv.c
@@ -399,6 +399,7 @@ static int storvsc_timeout = 180;
static struct scsi_transport_template *fc_transport_template;
#endif
+static struct scsi_host_template scsi_driver;
static void storvsc_on_channel_callback(void *context);
#define STORVSC_MAX_LUNS_PER_TARGET 255
@@ -698,6 +699,12 @@ static void handle_sc_creation(struct vmbus_channel *new_sc)
memset(&props, 0, sizeof(struct vmstorage_channel_properties));
+ /*
+ * The size of vmbus_requestor is an upper bound on the number of requests
+ * that can be in-progress at any one time across all channels.
+ */
+ new_sc->rqstor_size = scsi_driver.can_queue;
+
ret = vmbus_open(new_sc,
storvsc_ringbuffer_size,
storvsc_ringbuffer_size,
@@ -726,6 +733,7 @@ static void handle_multichannel_storage(struct hv_device *device, int max_chns)
struct storvsc_cmd_request *request;
struct vstor_packet *vstor_packet;
int ret, t;
+ u64 rqst_id;
/*
* If the number of CPUs is artificially restricted, such as
@@ -760,14 +768,23 @@ static void handle_multichannel_storage(struct hv_device *device, int max_chns)
vstor_packet->flags = REQUEST_COMPLETION_FLAG;
vstor_packet->sub_channel_count = num_sc;
+ rqst_id = vmbus_next_request_id(&device->channel->requestor,
+ (unsigned long)request);
+ if (rqst_id == VMBUS_RQST_ERROR) {
+ dev_err(dev, "No request id available\n");
+ return;
+ }
+
ret = vmbus_sendpacket(device->channel, vstor_packet,
(sizeof(struct vstor_packet) -
vmscsi_size_delta),
- (unsigned long)request,
+ rqst_id,
VM_PKT_DATA_INBAND,
VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
if (ret != 0) {
+ /* Reclaim request ID to avoid leak of IDs */
+ vmbus_request_addr(&device->channel->requestor, rqst_id);
dev_err(dev, "Failed to create sub-channel: err=%d\n", ret);
return;
}
@@ -818,20 +835,31 @@ static int storvsc_execute_vstor_op(struct hv_device *device,
{
struct vstor_packet *vstor_packet;
int ret, t;
+ u64 rqst_id;
vstor_packet = &request->vstor_packet;
init_completion(&request->wait_event);
vstor_packet->flags = REQUEST_COMPLETION_FLAG;
+ rqst_id = vmbus_next_request_id(&device->channel->requestor,
+ (unsigned long)request);
+ if (rqst_id == VMBUS_RQST_ERROR) {
+ dev_err(&device->device, "No request id available\n");
+ return -EAGAIN;
+ }
+
ret = vmbus_sendpacket(device->channel, vstor_packet,
(sizeof(struct vstor_packet) -
vmscsi_size_delta),
- (unsigned long)request,
+ rqst_id,
VM_PKT_DATA_INBAND,
VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
- if (ret != 0)
+ if (ret != 0) {
+ /* Reclaim request ID to avoid leak of IDs */
+ vmbus_request_addr(&device->channel->requestor, rqst_id);
return ret;
+ }
t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
if (t == 0)
@@ -1233,9 +1261,17 @@ static void storvsc_on_channel_callback(void *context)
foreach_vmbus_pkt(desc, channel) {
void *packet = hv_pkt_data(desc);
struct storvsc_cmd_request *request;
+ u64 cmd_rqst;
- request = (struct storvsc_cmd_request *)
- ((unsigned long)desc->trans_id);
+ cmd_rqst = vmbus_request_addr(&channel->requestor,
+ desc->trans_id);
+ if (cmd_rqst == VMBUS_RQST_ERROR) {
+ dev_err(&device->device,
+ "Incorrect transaction id\n");
+ continue;
+ }
+
+ request = (struct storvsc_cmd_request *)(unsigned long)cmd_rqst;
if (request == &stor_device->init_request ||
request == &stor_device->reset_request) {
@@ -1256,6 +1292,12 @@ static int storvsc_connect_to_vsp(struct hv_device *device, u32 ring_size,
memset(&props, 0, sizeof(struct vmstorage_channel_properties));
+ /*
+ * The size of vmbus_requestor is an upper bound on the number of requests
+ * that can be in-progress at any one time across all channels.
+ */
+ device->channel->rqstor_size = scsi_driver.can_queue;
+
ret = vmbus_open(device->channel,
ring_size,
ring_size,
@@ -1369,6 +1411,7 @@ static int storvsc_do_io(struct hv_device *device,
int ret = 0;
const struct cpumask *node_mask;
int tgt_cpu;
+ u64 rqst_id;
vstor_packet = &request->vstor_packet;
stor_device = get_out_stor_device(device);
@@ -1463,6 +1506,13 @@ static int storvsc_do_io(struct hv_device *device,
vstor_packet->operation = VSTOR_OPERATION_EXECUTE_SRB;
+ rqst_id = vmbus_next_request_id(&outgoing_channel->requestor,
+ (unsigned long)request);
+ if (rqst_id == VMBUS_RQST_ERROR) {
+ dev_err(&device->device, "No request id available\n");
+ return -EAGAIN;
+ }
+
if (request->payload->range.len) {
ret = vmbus_sendpacket_mpb_desc(outgoing_channel,
@@ -1470,18 +1520,21 @@ static int storvsc_do_io(struct hv_device *device,
vstor_packet,
(sizeof(struct vstor_packet) -
vmscsi_size_delta),
- (unsigned long)request);
+ rqst_id);
} else {
ret = vmbus_sendpacket(outgoing_channel, vstor_packet,
(sizeof(struct vstor_packet) -
vmscsi_size_delta),
- (unsigned long)request,
+ rqst_id,
VM_PKT_DATA_INBAND,
VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
}
- if (ret != 0)
+ if (ret != 0) {
+ /* Reclaim request ID to avoid leak of IDs */
+ vmbus_request_addr(&outgoing_channel->requestor, rqst_id);
return ret;
+ }
atomic_inc(&stor_device->num_outstanding_req);
@@ -1562,7 +1615,7 @@ static int storvsc_host_reset_handler(struct scsi_cmnd *scmnd)
struct storvsc_cmd_request *request;
struct vstor_packet *vstor_packet;
int ret, t;
-
+ u64 rqst_id;
stor_device = get_out_stor_device(device);
if (!stor_device)
@@ -1577,14 +1630,24 @@ static int storvsc_host_reset_handler(struct scsi_cmnd *scmnd)
vstor_packet->flags = REQUEST_COMPLETION_FLAG;
vstor_packet->vm_srb.path_id = stor_device->path_id;
+ rqst_id = vmbus_next_request_id(&device->channel->requestor,
+ (unsigned long)&stor_device->reset_request);
+ if (rqst_id == VMBUS_RQST_ERROR) {
+ dev_err(&device->device, "No request id available\n");
+ return FAILED;
+ }
+
ret = vmbus_sendpacket(device->channel, vstor_packet,
(sizeof(struct vstor_packet) -
vmscsi_size_delta),
- (unsigned long)&stor_device->reset_request,
+ rqst_id,
VM_PKT_DATA_INBAND,
VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
- if (ret != 0)
+ if (ret != 0) {
+ /* Reclaim request ID to avoid leak of IDs */
+ vmbus_request_addr(&device->channel->requestor, rqst_id);
return FAILED;
+ }
t = wait_for_completion_timeout(&request->wait_event, 5*HZ);
if (t == 0)
--
2.25.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH v6 3/3] hv_netvsc: Use vmbus_requestor to generate transaction IDs for VMBus hardening
2020-07-22 22:39 [PATCH v6 0/3] Drivers: hv: vmbus: vmbus_requestor data structure for VMBus hardening Andres Beltran
2020-07-22 22:39 ` [PATCH v6 1/3] Drivers: hv: vmbus: Add " Andres Beltran
2020-07-22 22:39 ` [PATCH v6 2/3] scsi: storvsc: Use vmbus_requestor to generate transaction IDs " Andres Beltran
@ 2020-07-22 22:39 ` Andres Beltran
2 siblings, 0 replies; 6+ messages in thread
From: Andres Beltran @ 2020-07-22 22:39 UTC (permalink / raw)
To: kys, haiyangz, sthemmin, wei.liu
Cc: linux-hyperv, linux-kernel, mikelley, parri.andrea,
Andres Beltran, David S . Miller, Jakub Kicinski, netdev
Currently, pointers to guest memory are passed to Hyper-V as
transaction IDs in netvsc. In the face of errors or malicious
behavior in Hyper-V, netvsc should not expose or trust the transaction
IDs returned by Hyper-V to be valid guest memory addresses. Instead,
use small integers generated by vmbus_requestor as requests
(transaction) IDs.
Cc: David S. Miller <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: netdev@vger.kernel.org
Signed-off-by: Andres Beltran <lkmlabelt@gmail.com>
Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>
Tested-by: Andrea Parri <parri.andrea@gmail.com>
Link: https://lore.kernel.org/r/20200701001221.2540-4-lkmlabelt@gmail.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
---
Changes in v2:
- Add casts to unsigned long to fix warnings on 32bit.
- Use an inline function to get the requestor size.
drivers/net/hyperv/hyperv_net.h | 13 +++++
drivers/net/hyperv/netvsc.c | 79 +++++++++++++++++++++++++------
drivers/net/hyperv/rndis_filter.c | 1 +
include/linux/hyperv.h | 1 +
4 files changed, 80 insertions(+), 14 deletions(-)
diff --git a/drivers/net/hyperv/hyperv_net.h b/drivers/net/hyperv/hyperv_net.h
index abda736e7c7d..f43b614f2345 100644
--- a/drivers/net/hyperv/hyperv_net.h
+++ b/drivers/net/hyperv/hyperv_net.h
@@ -847,6 +847,19 @@ struct nvsp_message {
#define NETVSC_XDP_HDRM 256
+#define NETVSC_MIN_OUT_MSG_SIZE (sizeof(struct vmpacket_descriptor) + \
+ sizeof(struct nvsp_message))
+#define NETVSC_MIN_IN_MSG_SIZE sizeof(struct vmpacket_descriptor)
+
+/* Estimated requestor size:
+ * out_ring_size/min_out_msg_size + in_ring_size/min_in_msg_size
+ */
+static inline u32 netvsc_rqstor_size(unsigned long ringbytes)
+{
+ return ringbytes / NETVSC_MIN_OUT_MSG_SIZE +
+ ringbytes / NETVSC_MIN_IN_MSG_SIZE;
+}
+
struct multi_send_data {
struct sk_buff *skb; /* skb containing the pkt */
struct hv_netvsc_packet *pkt; /* netvsc pkt pending */
diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
index 41f5cf0bb997..79b907a29433 100644
--- a/drivers/net/hyperv/netvsc.c
+++ b/drivers/net/hyperv/netvsc.c
@@ -50,7 +50,7 @@ void netvsc_switch_datapath(struct net_device *ndev, bool vf)
vmbus_sendpacket(dev->channel, init_pkt,
sizeof(struct nvsp_message),
- (unsigned long)init_pkt,
+ VMBUS_RQST_ID_NO_RESPONSE,
VM_PKT_DATA_INBAND, 0);
}
@@ -163,7 +163,7 @@ static void netvsc_revoke_recv_buf(struct hv_device *device,
ret = vmbus_sendpacket(device->channel,
revoke_packet,
sizeof(struct nvsp_message),
- (unsigned long)revoke_packet,
+ VMBUS_RQST_ID_NO_RESPONSE,
VM_PKT_DATA_INBAND, 0);
/* If the failure is because the channel is rescinded;
* ignore the failure since we cannot send on a rescinded
@@ -213,7 +213,7 @@ static void netvsc_revoke_send_buf(struct hv_device *device,
ret = vmbus_sendpacket(device->channel,
revoke_packet,
sizeof(struct nvsp_message),
- (unsigned long)revoke_packet,
+ VMBUS_RQST_ID_NO_RESPONSE,
VM_PKT_DATA_INBAND, 0);
/* If the failure is because the channel is rescinded;
@@ -304,6 +304,7 @@ static int netvsc_init_buf(struct hv_device *device,
unsigned int buf_size;
size_t map_words;
int ret = 0;
+ u64 rqst_id;
/* Get receive buffer area. */
buf_size = device_info->recv_sections * device_info->recv_section_size;
@@ -350,13 +351,22 @@ static int netvsc_init_buf(struct hv_device *device,
trace_nvsp_send(ndev, init_packet);
+ rqst_id = vmbus_next_request_id(&device->channel->requestor,
+ (unsigned long)init_packet);
+ if (rqst_id == VMBUS_RQST_ERROR) {
+ netdev_err(ndev, "No request id available\n");
+ goto cleanup;
+ }
+
/* Send the gpadl notification request */
ret = vmbus_sendpacket(device->channel, init_packet,
sizeof(struct nvsp_message),
- (unsigned long)init_packet,
+ rqst_id,
VM_PKT_DATA_INBAND,
VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
if (ret != 0) {
+ /* Reclaim request ID to avoid leak of IDs */
+ vmbus_request_addr(&device->channel->requestor, rqst_id);
netdev_err(ndev,
"unable to send receive buffer's gpadl to netvsp\n");
goto cleanup;
@@ -432,13 +442,22 @@ static int netvsc_init_buf(struct hv_device *device,
trace_nvsp_send(ndev, init_packet);
+ rqst_id = vmbus_next_request_id(&device->channel->requestor,
+ (unsigned long)init_packet);
+ if (rqst_id == VMBUS_RQST_ERROR) {
+ netdev_err(ndev, "No request id available\n");
+ goto cleanup;
+ }
+
/* Send the gpadl notification request */
ret = vmbus_sendpacket(device->channel, init_packet,
sizeof(struct nvsp_message),
- (unsigned long)init_packet,
+ rqst_id,
VM_PKT_DATA_INBAND,
VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
if (ret != 0) {
+ /* Reclaim request ID to avoid leak of IDs */
+ vmbus_request_addr(&device->channel->requestor, rqst_id);
netdev_err(ndev,
"unable to send send buffer's gpadl to netvsp\n");
goto cleanup;
@@ -496,6 +515,7 @@ static int negotiate_nvsp_ver(struct hv_device *device,
{
struct net_device *ndev = hv_get_drvdata(device);
int ret;
+ u64 rqst_id;
memset(init_packet, 0, sizeof(struct nvsp_message));
init_packet->hdr.msg_type = NVSP_MSG_TYPE_INIT;
@@ -503,15 +523,25 @@ static int negotiate_nvsp_ver(struct hv_device *device,
init_packet->msg.init_msg.init.max_protocol_ver = nvsp_ver;
trace_nvsp_send(ndev, init_packet);
+ rqst_id = vmbus_next_request_id(&device->channel->requestor,
+ (unsigned long)init_packet);
+ if (rqst_id == VMBUS_RQST_ERROR) {
+ netdev_err(ndev, "No request id available\n");
+ return -EAGAIN;
+ }
+
/* Send the init request */
ret = vmbus_sendpacket(device->channel, init_packet,
sizeof(struct nvsp_message),
- (unsigned long)init_packet,
+ rqst_id,
VM_PKT_DATA_INBAND,
VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
- if (ret != 0)
+ if (ret != 0) {
+ /* Reclaim request ID to avoid leak of IDs */
+ vmbus_request_addr(&device->channel->requestor, rqst_id);
return ret;
+ }
wait_for_completion(&net_device->channel_init_wait);
@@ -542,7 +572,7 @@ static int negotiate_nvsp_ver(struct hv_device *device,
ret = vmbus_sendpacket(device->channel, init_packet,
sizeof(struct nvsp_message),
- (unsigned long)init_packet,
+ VMBUS_RQST_ID_NO_RESPONSE,
VM_PKT_DATA_INBAND, 0);
return ret;
@@ -599,7 +629,7 @@ static int netvsc_connect_vsp(struct hv_device *device,
/* Send the init request */
ret = vmbus_sendpacket(device->channel, init_packet,
sizeof(struct nvsp_message),
- (unsigned long)init_packet,
+ VMBUS_RQST_ID_NO_RESPONSE,
VM_PKT_DATA_INBAND, 0);
if (ret != 0)
goto cleanup;
@@ -680,10 +710,19 @@ static void netvsc_send_tx_complete(struct net_device *ndev,
const struct vmpacket_descriptor *desc,
int budget)
{
- struct sk_buff *skb = (struct sk_buff *)(unsigned long)desc->trans_id;
+ struct sk_buff *skb;
struct net_device_context *ndev_ctx = netdev_priv(ndev);
u16 q_idx = 0;
int queue_sends;
+ u64 cmd_rqst;
+
+ cmd_rqst = vmbus_request_addr(&channel->requestor, (u64)desc->trans_id);
+ if (cmd_rqst == VMBUS_RQST_ERROR) {
+ netdev_err(ndev, "Incorrect transaction id\n");
+ return;
+ }
+
+ skb = (struct sk_buff *)(unsigned long)cmd_rqst;
/* Notify the layer above us */
if (likely(skb)) {
@@ -822,7 +861,7 @@ static inline int netvsc_send_pkt(
struct net_device *ndev = hv_get_drvdata(device);
struct net_device_context *ndev_ctx = netdev_priv(ndev);
struct netdev_queue *txq = netdev_get_tx_queue(ndev, packet->q_idx);
- u64 req_id;
+ u64 rqst_id;
int ret;
u32 ring_avail = hv_get_avail_to_write_percent(&out_channel->outbound);
@@ -838,13 +877,19 @@ static inline int netvsc_send_pkt(
else
rpkt->send_buf_section_size = packet->total_data_buflen;
- req_id = (ulong)skb;
if (out_channel->rescind)
return -ENODEV;
trace_nvsp_send_pkt(ndev, out_channel, rpkt);
+ rqst_id = vmbus_next_request_id(&out_channel->requestor,
+ (unsigned long)skb);
+ if (rqst_id == VMBUS_RQST_ERROR) {
+ ret = -EAGAIN;
+ goto ret_check;
+ }
+
if (packet->page_buf_cnt) {
if (packet->cp_partial)
pb += packet->rmsg_pgcnt;
@@ -852,14 +897,15 @@ static inline int netvsc_send_pkt(
ret = vmbus_sendpacket_pagebuffer(out_channel,
pb, packet->page_buf_cnt,
&nvmsg, sizeof(nvmsg),
- req_id);
+ rqst_id);
} else {
ret = vmbus_sendpacket(out_channel,
&nvmsg, sizeof(nvmsg),
- req_id, VM_PKT_DATA_INBAND,
+ rqst_id, VM_PKT_DATA_INBAND,
VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
}
+ret_check:
if (ret == 0) {
atomic_inc_return(&nvchan->queue_sends);
@@ -868,9 +914,13 @@ static inline int netvsc_send_pkt(
ndev_ctx->eth_stats.stop_queue++;
}
} else if (ret == -EAGAIN) {
+ /* Reclaim request ID to avoid leak of IDs */
+ vmbus_request_addr(&out_channel->requestor, rqst_id);
netif_tx_stop_queue(txq);
ndev_ctx->eth_stats.stop_queue++;
} else {
+ /* Reclaim request ID to avoid leak of IDs */
+ vmbus_request_addr(&out_channel->requestor, rqst_id);
netdev_err(ndev,
"Unable to send packet pages %u len %u, ret %d\n",
packet->page_buf_cnt, packet->total_data_buflen,
@@ -1422,6 +1472,7 @@ struct netvsc_device *netvsc_device_add(struct hv_device *device,
netvsc_poll, NAPI_POLL_WEIGHT);
/* Open the channel */
+ device->channel->rqstor_size = netvsc_rqstor_size(netvsc_ring_bytes);
ret = vmbus_open(device->channel, netvsc_ring_bytes,
netvsc_ring_bytes, NULL, 0,
netvsc_channel_cb, net_device->chan_table);
diff --git a/drivers/net/hyperv/rndis_filter.c b/drivers/net/hyperv/rndis_filter.c
index b81ceba38218..10489ba44a09 100644
--- a/drivers/net/hyperv/rndis_filter.c
+++ b/drivers/net/hyperv/rndis_filter.c
@@ -1114,6 +1114,7 @@ static void netvsc_sc_open(struct vmbus_channel *new_sc)
/* Set the channel before opening.*/
nvchan->channel = new_sc;
+ new_sc->rqstor_size = netvsc_rqstor_size(netvsc_ring_bytes);
ret = vmbus_open(new_sc, netvsc_ring_bytes,
netvsc_ring_bytes, NULL, 0,
netvsc_channel_cb, nvchan);
diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index c509d20ab7db..d8194924983d 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -730,6 +730,7 @@ struct vmbus_requestor {
};
#define VMBUS_RQST_ERROR U64_MAX
+#define VMBUS_RQST_ID_NO_RESPONSE (U64_MAX - 1)
struct vmbus_device {
u16 dev_type;
--
2.25.1
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