hv_netvsc: Copy packets sent by Hyper-V out of the receive buffer

Pointers to receive-buffer packets sent by Hyper-V are used within the
guest VM.  Hyper-V can send packets with erroneous values or modify
packet fields after they are processed by the guest.  To defend against
these scenarios, copy (sections of) the incoming packet after validating
their length and offset fields in netvsc_filter_receive().  In this way,
the packet can no longer be modified by the host.

Reported-by: Juan Vazquez <juvazq@microsoft.com>
Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com>
Link: https://lore.kernel.org/r/20210126162907.21056-1-parri.andrea@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 48 insertions, 45 deletions

diff --git a/drivers/net/hyperv/hyperv_net.h b/drivers/net/hyperv/hyperv_net.h
index 2a87cfa27ac0..e1a497d3c9ba 100644
--- a/drivers/net/hyperv/hyperv_net.h
+++ b/drivers/net/hyperv/hyperv_net.h
@@ -105,9 +105,43 @@ struct ndis_recv_scale_param { /* NDIS_RECEIVE_SCALE_PARAMETERS */
 	u32 processor_masks_entry_size;
 };
 
-/* Fwd declaration */
-struct ndis_tcp_ip_checksum_info;
-struct ndis_pkt_8021q_info;
+struct ndis_tcp_ip_checksum_info {
+	union {
+		struct {
+			u32 is_ipv4:1;
+			u32 is_ipv6:1;
+			u32 tcp_checksum:1;
+			u32 udp_checksum:1;
+			u32 ip_header_checksum:1;
+			u32 reserved:11;
+			u32 tcp_header_offset:10;
+		} transmit;
+		struct {
+			u32 tcp_checksum_failed:1;
+			u32 udp_checksum_failed:1;
+			u32 ip_checksum_failed:1;
+			u32 tcp_checksum_succeeded:1;
+			u32 udp_checksum_succeeded:1;
+			u32 ip_checksum_succeeded:1;
+			u32 loopback:1;
+			u32 tcp_checksum_value_invalid:1;
+			u32 ip_checksum_value_invalid:1;
+		} receive;
+		u32  value;
+	};
+};
+
+struct ndis_pkt_8021q_info {
+	union {
+		struct {
+			u32 pri:3; /* User Priority */
+			u32 cfi:1; /* Canonical Format ID */
+			u32 vlanid:12; /* VLAN ID */
+			u32 reserved:16;
+		};
+		u32 value;
+	};
+};
 
 /*
  * Represent netvsc packet which contains 1 RNDIS and 1 ethernet frame
@@ -194,7 +228,8 @@ int netvsc_send(struct net_device *net,
 		struct sk_buff *skb,
 		bool xdp_tx);
 void netvsc_linkstatus_callback(struct net_device *net,
-				struct rndis_message *resp);
+				struct rndis_message *resp,
+				void *data);
 int netvsc_recv_callback(struct net_device *net,
 			 struct netvsc_device *nvdev,
 			 struct netvsc_channel *nvchan);
@@ -884,9 +919,10 @@ struct multi_recv_comp {
 #define NVSP_RSC_MAX 562 /* Max #RSC frags in a vmbus xfer page pkt */
 
 struct nvsc_rsc {
-	const struct ndis_pkt_8021q_info *vlan;
-	const struct ndis_tcp_ip_checksum_info *csum_info;
-	const u32 *hash_info;
+	struct ndis_pkt_8021q_info vlan;
+	struct ndis_tcp_ip_checksum_info csum_info;
+	u32 hash_info;
+	u8 ppi_flags; /* valid/present bits for the above PPIs */
 	u8 is_last; /* last RNDIS msg in a vmtransfer_page */
 	u32 cnt; /* #fragments in an RSC packet */
 	u32 pktlen; /* Full packet length */
@@ -894,6 +930,10 @@ struct nvsc_rsc {
 	u32 len[NVSP_RSC_MAX];
 };
 
+#define NVSC_RSC_VLAN		BIT(0)	/* valid/present bit for 'vlan' */
+#define NVSC_RSC_CSUM_INFO	BIT(1)	/* valid/present bit for 'csum_info' */
+#define NVSC_RSC_HASH_INFO	BIT(2)	/* valid/present bit for 'hash_info' */
+
 struct netvsc_stats {
 	u64 packets;
 	u64 bytes;
@@ -1002,6 +1042,7 @@ struct net_device_context {
 struct netvsc_channel {
 	struct vmbus_channel *channel;
 	struct netvsc_device *net_device;
+	void *recv_buf; /* buffer to copy packets out from the receive buffer */
 	const struct vmpacket_descriptor *desc;
 	struct napi_struct napi;
 	struct multi_send_data msd;
@@ -1234,18 +1275,6 @@ struct rndis_pktinfo_id {
 	u16 pkt_id;
 };
 
-struct ndis_pkt_8021q_info {
-	union {
-		struct {
-			u32 pri:3; /* User Priority */
-			u32 cfi:1; /* Canonical Format ID */
-			u32 vlanid:12; /* VLAN ID */
-			u32 reserved:16;
-		};
-		u32 value;
-	};
-};
-
 struct ndis_object_header {
 	u8 type;
 	u8 revision;
@@ -1436,32 +1465,6 @@ struct ndis_offload_params {
 	};
 };
 
-struct ndis_tcp_ip_checksum_info {
-	union {
-		struct {
-			u32 is_ipv4:1;
-			u32 is_ipv6:1;
-			u32 tcp_checksum:1;
-			u32 udp_checksum:1;
-			u32 ip_header_checksum:1;
-			u32 reserved:11;
-			u32 tcp_header_offset:10;
-		} transmit;
-		struct {
-			u32 tcp_checksum_failed:1;
-			u32 udp_checksum_failed:1;
-			u32 ip_checksum_failed:1;
-			u32 tcp_checksum_succeeded:1;
-			u32 udp_checksum_succeeded:1;
-			u32 ip_checksum_succeeded:1;
-			u32 loopback:1;
-			u32 tcp_checksum_value_invalid:1;
-			u32 ip_checksum_value_invalid:1;
-		} receive;
-		u32  value;
-	};
-};
-
 struct ndis_tcp_lso_info {
 	union {
 		struct {