Messages in this thread Patch in this message | | | Subject | [PATCH 2/4] virt: sevguest: Prep for kernel internal {get, get_ext}_report() | From | Dan Williams <> | Date | Fri, 28 Jul 2023 12:31:04 -0700 |
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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 <bp@alien8.de> Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: Dionna Glaze <dionnaglaze@google.com> Cc: Brijesh Singh <brijesh.singh@amd.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com> --- 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;
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