From: Dan Williams <dan.j.williams@intel.com>
Date: Tue, 18 Jul 2023 17:55:50 -0700
Subject: virt: sevguest: Prep for kernel internal get_ext_report()
Git-commit: 2df2135366833c372f3a14ffcc655f9c5724d972
Patch-mainline: v6.7-rc1
References: jsc#PED-7167
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.
[ SLE15-SP5 backport: add the missing copy_to_sockptr() definition in sockptr.h
to avoid (partial) backport of 4ff09db1b79b98b4a2a7511571c640b76cab3beb ("bpf:
net: Change sk_getsockopt() to take the sockptr_t argument") ]
Cc: Borislav Petkov <bp@alien8.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Dionna Glaze <dionnaglaze@google.com>
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Tested-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
---
drivers/virt/coco/sev-guest/sev-guest.c | 44 +++++++++++++++++++++++---------
include/linux/sockptr.h | 5 +++
2 files changed, 37 insertions(+), 12 deletions(-)
--- 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>
@@ -475,6 +476,11 @@ static int handle_guest_request(struct s
return 0;
}
+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_guest_crypto *crypto = snp_dev->crypto;
@@ -555,22 +561,25 @@ static int get_derived_key(struct snp_gu
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_ext_report_req *req = &snp_dev->req.ext_report;
struct snp_guest_crypto *crypto = snp_dev->crypto;
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;
@@ -578,8 +587,13 @@ static int get_ext_report(struct snp_gue
!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
@@ -609,21 +623,19 @@ cmd:
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:
@@ -636,6 +648,7 @@ static long snp_guest_ioctl(struct file
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)))
@@ -664,7 +677,14 @@ static long snp_guest_ioctl(struct file
ret = get_derived_key(snp_dev, &input);
break;
case SNP_GET_EXT_REPORT:
- ret = get_ext_report(snp_dev, &input);
+ /*
+ * As get_ext_report() may be called from the ioctl() path and a
+ * kernel internal path (configfs-tsm), decorate the passed
+ * buffers as user pointers.
+ */
+ io.req_data = USER_SOCKPTR((void __user *)input.req_data);
+ io.resp_data = USER_SOCKPTR((void __user *)input.resp_data);
+ ret = get_ext_report(snp_dev, &input, &io);
break;
default:
break;
--- a/include/linux/sockptr.h
+++ b/include/linux/sockptr.h
@@ -64,6 +64,11 @@ static inline int copy_to_sockptr_offset
return 0;
}
+static inline int copy_to_sockptr(sockptr_t dst, const void *src, size_t size)
+{
+ return copy_to_sockptr_offset(dst, 0, src, size);
+}
+
static inline void *memdup_sockptr(sockptr_t src, size_t len)
{
void *p = kmalloc_track_caller(len, GFP_USER | __GFP_NOWARN);