[PATCH 5.14 150/169] scsi: storvsc: Fix validation for unsolicited incoming packets

Greg Kroah-Hartman
2021-10-25T19:58:06Z

From: Andrea Parri (Microsoft) <parri.andrea@gmail.com>

[ Upstream commit 6fd13d699d24beaa28310848fe65fd898fbb9043 ]

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 for such unsolicited packets.

Link: https://lore.kernel.org/r/20211007122828.469289-1-parri.andrea@gmail.com
Fixes: 91b1b640b834b2 ("scsi: storvsc: Validate length of incoming packet in storvsc_on_channel_callback()")
Reported-by: Dexuan Cui <decui@microsoft.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/scsi/storvsc_drv.c | 32 +++++++++++++++++++++++---------
1 file changed, 23 insertions(+), 9 deletions(-)

diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c
index 37506b3fe5a9..5fa1120a87f7 100644
--- a/drivers/scsi/storvsc_drv.c
+++ b/drivers/scsi/storvsc_drv.c
@@ -1285,11 +1285,15 @@ 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;
+ u32 minlen = rqst_id ? sizeof(struct vstor_packet) -
+ stor_device->vmscsi_size_delta : sizeof(enum vstor_packet_operation);

- if (hv_pkt_datalen(desc) < sizeof(struct vstor_packet) -
- stor_device->vmscsi_size_delta) {
- dev_err(&device->device, "Invalid packet len\n");
+ if (pktlen < minlen) {
+ dev_err(&device->device,
+ "Invalid pkt: id=%llu, len=%u, minlen=%u\n",
+ rqst_id, pktlen, minlen);
continue;
}

@@ -1302,13 +1306,23 @@ static void storvsc_on_channel_callback(void *context)
if (rqst_id == 0) {
/*
* storvsc_on_receive() looks at the vstor_packet in the message
- * from the ring buffer. If the operation in the vstor_packet is
- * COMPLETE_IO, then we call storvsc_on_io_completion(), and
- * dereference the guest memory address. Make sure we don't call
- * storvsc_on_io_completion() with a guest memory address that is
- * zero if Hyper-V were to construct and send such a bogus packet.
+ * from the ring buffer.
+ *
+ * - If the operation in the vstor_packet is COMPLETE_IO, then
+ * we call storvsc_on_io_completion(), and dereference the
+ * guest memory address. Make sure we don't call
+ * storvsc_on_io_completion() with a guest memory address
+ * that is zero if Hyper-V were to construct and send such
+ * a bogus packet.
+ *
+ * - If the operation in the vstor_packet is FCHBA_DATA, then
+ * we call cache_wwn(), and access the data payload area of
+ * the packet (wwn_packet); however, there is no guarantee
+ * that the packet is big enough to contain such area.
+ * Future-proof the code by rejecting such a bogus packet.
*/
- if (packet->operation == VSTOR_OPERATION_COMPLETE_IO) {
+ if (packet->operation == VSTOR_OPERATION_COMPLETE_IO ||
+ packet->operation == VSTOR_OPERATION_FCHBA_DATA) {
dev_err(&device->device, "Invalid packet with ID of 0\n");
continue;
}
--
2.33.0