The validation on the length of incoming packets performed in
storvsc_on_channel_callback() does not apply to "unsolicited"
packets with ID of 0 sent by Hyper-V. Adjust the validation
by handling such unsolicited packets separately.
Fixes: 91b1b640b834b2 ("scsi: storvsc: Validate length of incoming packet in storvsc_on_channel_callback()")
Reported-by: Dexuan Cui <decui@xxxxxxxxxxxxx>
Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@xxxxxxxxx>
---
The (new) bound, VSTOR_MIN_UNSOL_PKT_SIZE, was "empirically
derived" based on testing and code auditing. This explains
the RFC tag...
drivers/scsi/storvsc_drv.c | 17 ++++++++++++++---
1 file changed, 14 insertions(+), 3 deletions(-)
diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c
index ebbbc1299c625..a9bbcbbfb54ee 100644
--- a/drivers/scsi/storvsc_drv.c
+++ b/drivers/scsi/storvsc_drv.c
@@ -292,6 +292,9 @@ struct vmstorage_protocol_version {
#define STORAGE_CHANNEL_REMOVABLE_FLAG 0x1
#define STORAGE_CHANNEL_EMULATED_IDE_FLAG 0x2
+/* Lower bound on the size of unsolicited packets with ID of 0 */
+#define VSTOR_MIN_UNSOL_PKT_SIZE 48
+
struct vstor_packet {
/* Requested operation type */
enum vstor_packet_operation operation;
@@ -1285,11 +1288,13 @@ static void storvsc_on_channel_callback(void *context)
foreach_vmbus_pkt(desc, channel) {
struct vstor_packet *packet = hv_pkt_data(desc);
struct storvsc_cmd_request *request = NULL;
+ u32 pktlen = hv_pkt_datalen(desc);
u64 rqst_id = desc->trans_id;
- if (hv_pkt_datalen(desc) < sizeof(struct vstor_packet) -
+ /* Unsolicited packets with ID of 0 are validated separately below */
+ if (rqst_id != 0 && pktlen < sizeof(struct vstor_packet) -
stor_device->vmscsi_size_delta) {
- dev_err(&device->device, "Invalid packet len\n");
+ dev_err(&device->device, "Invalid packet: length=%u\n", pktlen);
continue;
}
@@ -1298,8 +1303,14 @@ static void storvsc_on_channel_callback(void *context)
} else if (rqst_id == VMBUS_RQST_RESET) {
request = &stor_device->reset_request;
} else {
- /* Hyper-V can send an unsolicited message with ID of 0 */
if (rqst_id == 0) {
+ if (pktlen < VSTOR_MIN_UNSOL_PKT_SIZE) {
+ dev_err(&device->device,
+ "Invalid packet with ID of 0: length=%u\n",
+ pktlen);
+ continue;
+ }
+
/*
* storvsc_on_receive() looks at the vstor_packet in the message
* from the ring buffer. If the operation in the vstor_packet is
--
2.25.1
