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PCI: hv: Use vmbus_requestor to generate transaction IDs for VMbus hardening 

Currently, pointers to guest memory are passed to Hyper-V as transaction
IDs in hv_pci.  In the face of errors or malicious behavior in Hyper-V,
hv_pci 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 request (transaction) IDs.

Suggested-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@gmail.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20220419122325.10078-3-parri.andrea@gmail.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
This commit is contained in:
Andrea Parri (Microsoft) 2022-04-19 14:23:21 +02:00 committed by Wei Liu
parent 82cd4bacff
commit de5ddb7d44
1 changed files with 29 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

39
drivers/pci/controller/pci-hyperv.c
View File

@ -91,6 +91,13 @@ static enum pci_protocol_version_t pci_protocol_versions[] = {
/* space for 32bit serial number as string */ /* space for 32bit serial number as string */
#define SLOT_NAME_SIZE 11 #define SLOT_NAME_SIZE 11
/*
* Size of requestor for VMbus; the value is based on the observation
* that having more than one request outstanding is 'rare', and so 64
* should be generous in ensuring that we don't ever run out.
*/
#define HV_PCI_RQSTOR_SIZE 64
/* /*
* Message Types * Message Types
*/ */
@ -1529,7 +1536,7 @@ static void hv_int_desc_free(struct hv_pci_dev *hpdev,
int_pkt->wslot.slot = hpdev->desc.win_slot.slot; int_pkt->wslot.slot = hpdev->desc.win_slot.slot;
int_pkt->int_desc = *int_desc; int_pkt->int_desc = *int_desc;
vmbus_sendpacket(hpdev->hbus->hdev->channel, int_pkt, sizeof(*int_pkt), vmbus_sendpacket(hpdev->hbus->hdev->channel, int_pkt, sizeof(*int_pkt),
(unsigned long)&ctxt.pkt, VM_PKT_DATA_INBAND, 0); 0, VM_PKT_DATA_INBAND, 0);
kfree(int_desc); kfree(int_desc);
} }
@ -2661,7 +2668,7 @@ static void hv_eject_device_work(struct work_struct *work)
ejct_pkt->message_type.type = PCI_EJECTION_COMPLETE; ejct_pkt->message_type.type = PCI_EJECTION_COMPLETE;
ejct_pkt->wslot.slot = hpdev->desc.win_slot.slot; ejct_pkt->wslot.slot = hpdev->desc.win_slot.slot;
vmbus_sendpacket(hbus->hdev->channel, ejct_pkt, vmbus_sendpacket(hbus->hdev->channel, ejct_pkt,
sizeof(*ejct_pkt), (unsigned long)&ctxt.pkt, sizeof(*ejct_pkt), 0,
VM_PKT_DATA_INBAND, 0); VM_PKT_DATA_INBAND, 0);
/* For the get_pcichild() in hv_pci_eject_device() */ /* For the get_pcichild() in hv_pci_eject_device() */
@ -2708,8 +2715,9 @@ static void hv_pci_onchannelcallback(void *context)
const int packet_size = 0x100; const int packet_size = 0x100;
int ret; int ret;
struct hv_pcibus_device *hbus = context; struct hv_pcibus_device *hbus = context;
struct vmbus_channel *chan = hbus->hdev->channel;
u32 bytes_recvd; u32 bytes_recvd;
u64 req_id; u64 req_id, req_addr;
struct vmpacket_descriptor *desc; struct vmpacket_descriptor *desc;
unsigned char *buffer; unsigned char *buffer;
int bufferlen = packet_size; int bufferlen = packet_size;
@ -2727,8 +2735,8 @@ static void hv_pci_onchannelcallback(void *context)
return; return;
while (1) { while (1) {
ret = vmbus_recvpacket_raw(hbus->hdev->channel, buffer, ret = vmbus_recvpacket_raw(chan, buffer, bufferlen,
bufferlen, &bytes_recvd, &req_id); &bytes_recvd, &req_id);
if (ret == -ENOBUFS) { if (ret == -ENOBUFS) {
kfree(buffer); kfree(buffer);
@ -2755,11 +2763,14 @@ static void hv_pci_onchannelcallback(void *context)
switch (desc->type) { switch (desc->type) {
case VM_PKT_COMP: case VM_PKT_COMP:
/* req_addr = chan->request_addr_callback(chan, req_id);
* The host is trusted, and thus it's safe to interpret if (req_addr == VMBUS_RQST_ERROR) {
* this transaction ID as a pointer. dev_err(&hbus->hdev->device,
*/ "Invalid transaction ID %llx\n",
comp_packet = (struct pci_packet *)req_id; req_id);
break;
}
comp_packet = (struct pci_packet *)req_addr;
response = (struct pci_response *)buffer; response = (struct pci_response *)buffer;
comp_packet->completion_func(comp_packet->compl_ctxt, comp_packet->completion_func(comp_packet->compl_ctxt,
response, response,
@ -3440,6 +3451,10 @@ static int hv_pci_probe(struct hv_device *hdev,
goto free_dom; goto free_dom;
} }
hdev->channel->next_request_id_callback = vmbus_next_request_id;
hdev->channel->request_addr_callback = vmbus_request_addr;
hdev->channel->rqstor_size = HV_PCI_RQSTOR_SIZE;
ret = vmbus_open(hdev->channel, pci_ring_size, pci_ring_size, NULL, 0, ret = vmbus_open(hdev->channel, pci_ring_size, pci_ring_size, NULL, 0,
hv_pci_onchannelcallback, hbus); hv_pci_onchannelcallback, hbus);
if (ret) if (ret)
@ -3770,6 +3785,10 @@ static int hv_pci_resume(struct hv_device *hdev)
hbus->state = hv_pcibus_init; hbus->state = hv_pcibus_init;
hdev->channel->next_request_id_callback = vmbus_next_request_id;
hdev->channel->request_addr_callback = vmbus_request_addr;
hdev->channel->rqstor_size = HV_PCI_RQSTOR_SIZE;
ret = vmbus_open(hdev->channel, pci_ring_size, pci_ring_size, NULL, 0, ret = vmbus_open(hdev->channel, pci_ring_size, pci_ring_size, NULL, 0,
hv_pci_onchannelcallback, hbus); hv_pci_onchannelcallback, hbus);
if (ret) if (ret)