In preparation for using the TSM key facility to convey attestation blobs
to userspace, add an argument to flag whether @arg is a user buffer or a
kernel buffer.
While TSM keys is meant to replace existing confidenital computing
ioctl() implementations for attestation report retrieval the old ioctl()
path needs to stick around for a deprecation period.
No behavior change intended, just introduce the copy wrappers and @type
argument.
Note that these wrappers are similar to copy_{to,from}_sockptr(). If
this approach moves forward that concept is something that can be
generalized into a helper with a generic name.
Cc: Borislav Petkov <[email protected]>
Cc: Tom Lendacky <[email protected]>
Cc: Dionna Glaze <[email protected]>
Cc: Brijesh Singh <[email protected]>
Signed-off-by: Dan Williams <[email protected]>
---
drivers/virt/coco/sev-guest/sev-guest.c | 48 ++++++++++++++++++++++++-------
1 file changed, 37 insertions(+), 11 deletions(-)
diff --git a/drivers/virt/coco/sev-guest/sev-guest.c b/drivers/virt/coco/sev-guest/sev-guest.c
index 97dbe715e96a..f48c4764a7a2 100644
--- a/drivers/virt/coco/sev-guest/sev-guest.c
+++ b/drivers/virt/coco/sev-guest/sev-guest.c
@@ -470,7 +470,32 @@ static int handle_guest_request(struct snp_guest_dev *snp_dev, u64 exit_code,
return 0;
}
-static int get_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_ioctl *arg)
+enum snp_arg_type {
+ SNP_UARG,
+ SNP_KARG,
+};
+
+static unsigned long copy_from(void *to, unsigned long from, unsigned long n,
+ enum snp_arg_type type)
+{
+ if (type == SNP_UARG)
+ return copy_from_user(to, (void __user *)from, n);
+ memcpy(to, (void *)from, n);
+ return 0;
+}
+
+static unsigned long copy_to(unsigned long to, const void *from,
+ unsigned long n, enum snp_arg_type type)
+{
+ if (type == SNP_UARG)
+ return copy_to_user((void __user *)to, from, n);
+ memcpy((void *)to, from, n);
+ return 0;
+}
+
+static int get_report(struct snp_guest_dev *snp_dev,
+ struct snp_guest_request_ioctl *arg,
+ enum snp_arg_type type)
{
struct snp_guest_crypto *crypto = snp_dev->crypto;
struct snp_report_resp *resp;
@@ -482,7 +507,7 @@ static int get_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_io
if (!arg->req_data || !arg->resp_data)
return -EINVAL;
- if (copy_from_user(&req, (void __user *)arg->req_data, sizeof(req)))
+ if (copy_from(&req, arg->req_data, sizeof(req), type))
return -EFAULT;
/*
@@ -501,7 +526,7 @@ static int get_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_io
if (rc)
goto e_free;
- if (copy_to_user((void __user *)arg->resp_data, resp, sizeof(*resp)))
+ if (copy_to(arg->resp_data, resp, sizeof(*resp), type))
rc = -EFAULT;
e_free:
@@ -550,7 +575,9 @@ static int get_derived_key(struct snp_guest_dev *snp_dev, struct snp_guest_reque
return rc;
}
-static int get_ext_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_ioctl *arg)
+static int get_ext_report(struct snp_guest_dev *snp_dev,
+ struct snp_guest_request_ioctl *arg,
+ enum snp_arg_type type)
{
struct snp_guest_crypto *crypto = snp_dev->crypto;
struct snp_ext_report_req req;
@@ -562,7 +589,7 @@ static int get_ext_report(struct snp_guest_dev *snp_dev, struct snp_guest_reques
if (!arg->req_data || !arg->resp_data)
return -EINVAL;
- if (copy_from_user(&req, (void __user *)arg->req_data, sizeof(req)))
+ if (copy_from(&req, arg->req_data, sizeof(req), type))
return -EFAULT;
/* userspace does not want certificate data */
@@ -611,14 +638,13 @@ static int get_ext_report(struct snp_guest_dev *snp_dev, struct snp_guest_reques
if (ret)
goto e_free;
- if (npages &&
- copy_to_user((void __user *)req.certs_address, snp_dev->certs_data,
- req.certs_len)) {
+ if (npages && copy_to(req.certs_address, snp_dev->certs_data,
+ req.certs_len, type)) {
ret = -EFAULT;
goto e_free;
}
- if (copy_to_user((void __user *)arg->resp_data, resp, sizeof(*resp)))
+ if (copy_to(arg->resp_data, resp, sizeof(*resp), type))
ret = -EFAULT;
e_free:
@@ -653,13 +679,13 @@ static long snp_guest_ioctl(struct file *file, unsigned int ioctl, unsigned long
switch (ioctl) {
case SNP_GET_REPORT:
- ret = get_report(snp_dev, &input);
+ ret = get_report(snp_dev, &input, SNP_UARG);
break;
case SNP_GET_DERIVED_KEY:
ret = get_derived_key(snp_dev, &input);
break;
case SNP_GET_EXT_REPORT:
- ret = get_ext_report(snp_dev, &input);
+ ret = get_ext_report(snp_dev, &input, SNP_UARG);
break;
default:
break;