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Message-ID: <169570183602.596431.6477217304734993370.stgit@dwillia2-xfh.jf.intel.com>
Date: Mon, 25 Sep 2023 21:17:16 -0700
From: Dan Williams <dan.j.williams@...el.com>
To: linux-coco@...ts.linux.dev
Cc: Borislav Petkov <bp@...en8.de>,
Tom Lendacky <thomas.lendacky@....com>,
Dionna Glaze <dionnaglaze@...gle.com>,
Brijesh Singh <brijesh.singh@....com>, peterz@...radead.org,
linux-kernel@...r.kernel.org, x86@...nel.org,
dave.hansen@...ux.intel.com
Subject: [PATCH v4 3/6] virt: sevguest: Prep for kernel internal {get,
get_ext}_report()
In preparation for using the configs-tsm facility to convey attestation
blobs to userspace, switch to using the 'sockptr' api for copying
payloads to provided buffers where 'sockptr' handles user vs kernel
buffers.
While configfs-tsm is meant to replace existing confidential computing
ioctl() implementations for attestation report retrieval the old ioctl()
path needs to stick around for a deprecation period.
No behavior change intended.
Cc: Borislav Petkov <bp@...en8.de>
Cc: Tom Lendacky <thomas.lendacky@....com>
Cc: Dionna Glaze <dionnaglaze@...gle.com>
Cc: Brijesh Singh <brijesh.singh@....com>
Signed-off-by: Dan Williams <dan.j.williams@...el.com>
---
drivers/virt/coco/sev-guest/sev-guest.c | 50 ++++++++++++++++++++-----------
1 file changed, 33 insertions(+), 17 deletions(-)
diff --git a/drivers/virt/coco/sev-guest/sev-guest.c b/drivers/virt/coco/sev-guest/sev-guest.c
index 97dbe715e96a..c3c9e9ea691f 100644
--- a/drivers/virt/coco/sev-guest/sev-guest.c
+++ b/drivers/virt/coco/sev-guest/sev-guest.c
@@ -19,6 +19,7 @@
#include <crypto/aead.h>
#include <linux/scatterlist.h>
#include <linux/psp-sev.h>
+#include <linux/sockptr.h>
#include <uapi/linux/sev-guest.h>
#include <uapi/linux/psp-sev.h>
@@ -470,7 +471,13 @@ 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)
+struct snp_req_resp {
+ sockptr_t req_data;
+ sockptr_t resp_data;
+};
+
+static int get_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_ioctl *arg,
+ struct snp_req_resp *io)
{
struct snp_guest_crypto *crypto = snp_dev->crypto;
struct snp_report_resp *resp;
@@ -479,10 +486,10 @@ static int get_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_io
lockdep_assert_held(&snp_cmd_mutex);
- if (!arg->req_data || !arg->resp_data)
+ if (sockptr_is_null(io->req_data) || sockptr_is_null(io->resp_data))
return -EINVAL;
- if (copy_from_user(&req, (void __user *)arg->req_data, sizeof(req)))
+ if (copy_from_sockptr(&req, io->req_data, sizeof(req)))
return -EFAULT;
/*
@@ -501,7 +508,7 @@ 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_sockptr(io->resp_data, resp, sizeof(*resp)))
rc = -EFAULT;
e_free:
@@ -550,22 +557,25 @@ 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,
+ struct snp_req_resp *io)
+
{
struct snp_guest_crypto *crypto = snp_dev->crypto;
struct snp_ext_report_req req;
struct snp_report_resp *resp;
int ret, npages = 0, resp_len;
+ sockptr_t certs_address;
lockdep_assert_held(&snp_cmd_mutex);
- if (!arg->req_data || !arg->resp_data)
+ if (sockptr_is_null(io->req_data) || sockptr_is_null(io->resp_data))
return -EINVAL;
- if (copy_from_user(&req, (void __user *)arg->req_data, sizeof(req)))
+ if (copy_from_sockptr(&req, io->req_data, sizeof(req)))
return -EFAULT;
- /* userspace does not want certificate data */
+ /* caller does not want certificate data */
if (!req.certs_len || !req.certs_address)
goto cmd;
@@ -573,8 +583,13 @@ static int get_ext_report(struct snp_guest_dev *snp_dev, struct snp_guest_reques
!IS_ALIGNED(req.certs_len, PAGE_SIZE))
return -EINVAL;
- if (!access_ok((const void __user *)req.certs_address, req.certs_len))
- return -EFAULT;
+ if (sockptr_is_kernel(io->resp_data)) {
+ certs_address = KERNEL_SOCKPTR((void *)req.certs_address);
+ } else {
+ certs_address = USER_SOCKPTR((void __user *)req.certs_address);
+ if (!access_ok(certs_address.user, req.certs_len))
+ return -EFAULT;
+ }
/*
* Initialize the intermediate buffer with all zeros. This buffer
@@ -604,21 +619,19 @@ static int get_ext_report(struct snp_guest_dev *snp_dev, struct snp_guest_reques
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)))
+ if (copy_to_sockptr(io->req_data, &req, sizeof(req)))
ret = -EFAULT;
}
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_sockptr(certs_address, snp_dev->certs_data, req.certs_len)) {
ret = -EFAULT;
goto e_free;
}
- if (copy_to_user((void __user *)arg->resp_data, resp, sizeof(*resp)))
+ if (copy_to_sockptr(io->resp_data, resp, sizeof(*resp)))
ret = -EFAULT;
e_free:
@@ -631,6 +644,7 @@ static long snp_guest_ioctl(struct file *file, unsigned int ioctl, unsigned long
struct snp_guest_dev *snp_dev = to_snp_dev(file);
void __user *argp = (void __user *)arg;
struct snp_guest_request_ioctl input;
+ struct snp_req_resp io;
int ret = -ENOTTY;
if (copy_from_user(&input, argp, sizeof(input)))
@@ -651,15 +665,17 @@ static long snp_guest_ioctl(struct file *file, unsigned int ioctl, unsigned long
return -ENOTTY;
}
+ io.req_data = USER_SOCKPTR((void __user *)input.req_data);
+ io.resp_data = USER_SOCKPTR((void __user *)input.resp_data);
switch (ioctl) {
case SNP_GET_REPORT:
- ret = get_report(snp_dev, &input);
+ ret = get_report(snp_dev, &input, &io);
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, &io);
break;
default:
break;
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