[PATCH v7 3/3] hv_netvsc: Use vmbus_requestor to generate transaction IDs for VMBus hardening
From: "Andrea Parri (Microsoft)" <parri.andrea@gmail.com>
Date: 2020-09-07 16:20:49
Also in:
linux-hyperv, lkml
Subsystem:
hyper-v/azure core and drivers, networking drivers, the rest · Maintainers:
"K. Y. Srinivasan", Haiyang Zhang, Wei Liu, Dexuan Cui, Long Li, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
From: Andres Beltran <redacted>
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.
Signed-off-by: Andres Beltran <redacted>
Co-developed-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com>
Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: netdev@vger.kernel.org
---
Changes in v7:
- Move the allocation of the request ID after the data has been
copied into the ring buffer (cf. 1/3).
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 | 22 ++++++++++++++++------
drivers/net/hyperv/rndis_filter.c | 1 +
include/linux/hyperv.h | 1 +
4 files changed, 31 insertions(+), 6 deletions(-)
diff --git a/drivers/net/hyperv/hyperv_net.h b/drivers/net/hyperv/hyperv_net.h
index 2181d4538ab70..4d2b2d48ff2a1 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 41f5cf0bb9971..03e93e3ddbad8 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;
@@ -542,7 +542,7 @@ 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 +599,7 @@ 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 +680,19 @@ 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)) {
@@ -1422,6 +1431,7 @@ 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 b81ceba38218c..10489ba44a090 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 45c7831ba0ef1..32c03643577b4 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h@@ -731,6 +731,7 @@ struct vmbus_requestor { #define VMBUS_NO_RQSTOR U64_MAX #define VMBUS_RQST_ERROR (U64_MAX - 1) +#define VMBUS_RQST_ID_NO_RESPONSE (U64_MAX - 2) struct vmbus_device { u16 dev_type;
--
2.25.1