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-rw-r--r--drivers/virt/coco/sev-guest/sev-guest.c99
-rw-r--r--drivers/virt/fsl_hypervisor.c2
2 files changed, 63 insertions, 38 deletions
diff --git a/drivers/virt/coco/sev-guest/sev-guest.c b/drivers/virt/coco/sev-guest/sev-guest.c
index 46f1a8d558b0..97dbe715e96a 100644
--- a/drivers/virt/coco/sev-guest/sev-guest.c
+++ b/drivers/virt/coco/sev-guest/sev-guest.c
@@ -46,7 +46,15 @@ struct snp_guest_dev {
void *certs_data;
struct snp_guest_crypto *crypto;
+ /* request and response are in unencrypted memory */
struct snp_guest_msg *request, *response;
+
+ /*
+ * Avoid information leakage by double-buffering shared messages
+ * in fields that are in regular encrypted memory.
+ */
+ struct snp_guest_msg secret_request, secret_response;
+
struct snp_secrets_page_layout *layout;
struct snp_req_data input;
u32 *os_area_msg_seqno;
@@ -266,14 +274,17 @@ static int dec_payload(struct snp_guest_dev *snp_dev, struct snp_guest_msg *msg,
static int verify_and_dec_payload(struct snp_guest_dev *snp_dev, void *payload, u32 sz)
{
struct snp_guest_crypto *crypto = snp_dev->crypto;
- struct snp_guest_msg *resp = snp_dev->response;
- struct snp_guest_msg *req = snp_dev->request;
+ struct snp_guest_msg *resp = &snp_dev->secret_response;
+ struct snp_guest_msg *req = &snp_dev->secret_request;
struct snp_guest_msg_hdr *req_hdr = &req->hdr;
struct snp_guest_msg_hdr *resp_hdr = &resp->hdr;
dev_dbg(snp_dev->dev, "response [seqno %lld type %d version %d sz %d]\n",
resp_hdr->msg_seqno, resp_hdr->msg_type, resp_hdr->msg_version, resp_hdr->msg_sz);
+ /* Copy response from shared memory to encrypted memory. */
+ memcpy(resp, snp_dev->response, sizeof(*resp));
+
/* Verify that the sequence counter is incremented by 1 */
if (unlikely(resp_hdr->msg_seqno != (req_hdr->msg_seqno + 1)))
return -EBADMSG;
@@ -297,7 +308,7 @@ static int verify_and_dec_payload(struct snp_guest_dev *snp_dev, void *payload,
static int enc_payload(struct snp_guest_dev *snp_dev, u64 seqno, int version, u8 type,
void *payload, size_t sz)
{
- struct snp_guest_msg *req = snp_dev->request;
+ struct snp_guest_msg *req = &snp_dev->secret_request;
struct snp_guest_msg_hdr *hdr = &req->hdr;
memset(req, 0, sizeof(*req));
@@ -321,11 +332,12 @@ static int enc_payload(struct snp_guest_dev *snp_dev, u64 seqno, int version, u8
return __enc_payload(snp_dev, req, payload, sz);
}
-static int __handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, __u64 *fw_err)
+static int __handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code,
+ struct snp_guest_request_ioctl *rio)
{
- unsigned long err = 0xff, override_err = 0;
unsigned long req_start = jiffies;
unsigned int override_npages = 0;
+ u64 override_err = 0;
int rc;
retry_request:
@@ -335,7 +347,7 @@ retry_request:
* sequence number must be incremented or the VMPCK must be deleted to
* prevent reuse of the IV.
*/
- rc = snp_issue_guest_request(exit_code, &snp_dev->input, &err);
+ rc = snp_issue_guest_request(exit_code, &snp_dev->input, rio);
switch (rc) {
case -ENOSPC:
/*
@@ -353,7 +365,7 @@ retry_request:
* request buffer size was too small and give the caller the
* required buffer size.
*/
- override_err = SNP_GUEST_REQ_INVALID_LEN;
+ override_err = SNP_GUEST_VMM_ERR(SNP_GUEST_VMM_ERR_INVALID_LEN);
/*
* If this call to the firmware succeeds, the sequence number can
@@ -366,7 +378,7 @@ retry_request:
goto retry_request;
/*
- * The host may return SNP_GUEST_REQ_ERR_EBUSY if the request has been
+ * The host may return SNP_GUEST_VMM_ERR_BUSY if the request has been
* throttled. Retry in the driver to avoid returning and reusing the
* message sequence number on a different message.
*/
@@ -387,27 +399,29 @@ retry_request:
*/
snp_inc_msg_seqno(snp_dev);
- if (fw_err)
- *fw_err = override_err ?: err;
+ if (override_err) {
+ rio->exitinfo2 = override_err;
+
+ /*
+ * If an extended guest request was issued and the supplied certificate
+ * buffer was not large enough, a standard guest request was issued to
+ * prevent IV reuse. If the standard request was successful, return -EIO
+ * back to the caller as would have originally been returned.
+ */
+ if (!rc && override_err == SNP_GUEST_VMM_ERR(SNP_GUEST_VMM_ERR_INVALID_LEN))
+ rc = -EIO;
+ }
if (override_npages)
snp_dev->input.data_npages = override_npages;
- /*
- * If an extended guest request was issued and the supplied certificate
- * buffer was not large enough, a standard guest request was issued to
- * prevent IV reuse. If the standard request was successful, return -EIO
- * back to the caller as would have originally been returned.
- */
- if (!rc && override_err == SNP_GUEST_REQ_INVALID_LEN)
- return -EIO;
-
return rc;
}
-static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, int msg_ver,
- u8 type, void *req_buf, size_t req_sz, void *resp_buf,
- u32 resp_sz, __u64 *fw_err)
+static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code,
+ struct snp_guest_request_ioctl *rio, u8 type,
+ void *req_buf, size_t req_sz, void *resp_buf,
+ u32 resp_sz)
{
u64 seqno;
int rc;
@@ -417,19 +431,31 @@ static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code, in
if (!seqno)
return -EIO;
+ /* Clear shared memory's response for the host to populate. */
memset(snp_dev->response, 0, sizeof(struct snp_guest_msg));
- /* Encrypt the userspace provided payload */
- rc = enc_payload(snp_dev, seqno, msg_ver, type, req_buf, req_sz);
+ /* Encrypt the userspace provided payload in snp_dev->secret_request. */
+ rc = enc_payload(snp_dev, seqno, rio->msg_version, type, req_buf, req_sz);
if (rc)
return rc;
- rc = __handle_guest_request(snp_dev, exit_code, fw_err);
+ /*
+ * Write the fully encrypted request to the shared unencrypted
+ * request page.
+ */
+ memcpy(snp_dev->request, &snp_dev->secret_request,
+ sizeof(snp_dev->secret_request));
+
+ rc = __handle_guest_request(snp_dev, exit_code, rio);
if (rc) {
- if (rc == -EIO && *fw_err == SNP_GUEST_REQ_INVALID_LEN)
+ if (rc == -EIO &&
+ rio->exitinfo2 == SNP_GUEST_VMM_ERR(SNP_GUEST_VMM_ERR_INVALID_LEN))
return rc;
- dev_alert(snp_dev->dev, "Detected error from ASP request. rc: %d, fw_err: %llu\n", rc, *fw_err);
+ dev_alert(snp_dev->dev,
+ "Detected error from ASP request. rc: %d, exitinfo2: 0x%llx\n",
+ rc, rio->exitinfo2);
+
snp_disable_vmpck(snp_dev);
return rc;
}
@@ -469,9 +495,9 @@ static int get_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_io
if (!resp)
return -ENOMEM;
- rc = handle_guest_request(snp_dev, SVM_VMGEXIT_GUEST_REQUEST, arg->msg_version,
+ rc = handle_guest_request(snp_dev, SVM_VMGEXIT_GUEST_REQUEST, arg,
SNP_MSG_REPORT_REQ, &req, sizeof(req), resp->data,
- resp_len, &arg->fw_err);
+ resp_len);
if (rc)
goto e_free;
@@ -509,9 +535,8 @@ static int get_derived_key(struct snp_guest_dev *snp_dev, struct snp_guest_reque
if (copy_from_user(&req, (void __user *)arg->req_data, sizeof(req)))
return -EFAULT;
- rc = handle_guest_request(snp_dev, SVM_VMGEXIT_GUEST_REQUEST, arg->msg_version,
- SNP_MSG_KEY_REQ, &req, sizeof(req), buf, resp_len,
- &arg->fw_err);
+ rc = handle_guest_request(snp_dev, SVM_VMGEXIT_GUEST_REQUEST, arg,
+ SNP_MSG_KEY_REQ, &req, sizeof(req), buf, resp_len);
if (rc)
return rc;
@@ -571,12 +596,12 @@ cmd:
return -ENOMEM;
snp_dev->input.data_npages = npages;
- ret = handle_guest_request(snp_dev, SVM_VMGEXIT_EXT_GUEST_REQUEST, arg->msg_version,
+ ret = handle_guest_request(snp_dev, SVM_VMGEXIT_EXT_GUEST_REQUEST, arg,
SNP_MSG_REPORT_REQ, &req.data,
- sizeof(req.data), resp->data, resp_len, &arg->fw_err);
+ sizeof(req.data), resp->data, resp_len);
/* If certs length is invalid then copy the returned length */
- if (arg->fw_err == SNP_GUEST_REQ_INVALID_LEN) {
+ if (arg->vmm_error == SNP_GUEST_VMM_ERR_INVALID_LEN) {
req.certs_len = snp_dev->input.data_npages << PAGE_SHIFT;
if (copy_to_user((void __user *)arg->req_data, &req, sizeof(req)))
@@ -611,7 +636,7 @@ static long snp_guest_ioctl(struct file *file, unsigned int ioctl, unsigned long
if (copy_from_user(&input, argp, sizeof(input)))
return -EFAULT;
- input.fw_err = 0xff;
+ input.exitinfo2 = 0xff;
/* Message version must be non-zero */
if (!input.msg_version)
@@ -642,7 +667,7 @@ static long snp_guest_ioctl(struct file *file, unsigned int ioctl, unsigned long
mutex_unlock(&snp_cmd_mutex);
- if (input.fw_err && copy_to_user(argp, &input, sizeof(input)))
+ if (input.exitinfo2 && copy_to_user(argp, &input, sizeof(input)))
return -EFAULT;
return ret;
diff --git a/drivers/virt/fsl_hypervisor.c b/drivers/virt/fsl_hypervisor.c
index f8b4389d60d9..e92e2ceb12a4 100644
--- a/drivers/virt/fsl_hypervisor.c
+++ b/drivers/virt/fsl_hypervisor.c
@@ -796,7 +796,7 @@ static int has_fsl_hypervisor(void)
if (!node)
return 0;
- ret = of_find_property(node, "fsl,hv-version", NULL) != NULL;
+ ret = of_property_present(node, "fsl,hv-version");
of_node_put(node);
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