[Part2 PATCH v6.1 18/38] crypto: ccp: Implement SEV_PEK_CSR ioctl command

From: Brijesh Singh
Date: Mon Oct 23 2017 - 18:08:06 EST


The SEV_PEK_CSR command can be used to generate a PEK certificate
signing request. The command is defined in SEV spec section 5.7.

Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: "Radim KrÄmÃÅ" <rkrcmar@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxx>
Cc: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Cc: Gary Hook <gary.hook@xxxxxxx>
Cc: Tom Lendacky <thomas.lendacky@xxxxxxx>
Cc: linux-crypto@xxxxxxxxxxxxxxx
Cc: kvm@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: Brijesh Singh <brijesh.singh@xxxxxxx>
---

Changes since v6:
* when sev_do_cmd() and sev_platform_shutdown() fails then propogate
the error status code from sev_do_cmd() because it can give us
much better reason for the failure.

drivers/crypto/ccp/psp-dev.c | 81 ++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 81 insertions(+)

diff --git a/drivers/crypto/ccp/psp-dev.c b/drivers/crypto/ccp/psp-dev.c
index 3672435150cf..aaf1c5cf821d 100644
--- a/drivers/crypto/ccp/psp-dev.c
+++ b/drivers/crypto/ccp/psp-dev.c
@@ -223,6 +223,84 @@ static int sev_ioctl_do_pek_pdh_gen(int cmd, struct sev_issue_cmd *argp)
return ret;
}

+static int sev_ioctl_do_pek_csr(struct sev_issue_cmd *argp)
+{
+ struct sev_user_data_pek_csr input;
+ struct sev_data_pek_csr *data;
+ void *blob = NULL;
+ int ret, err;
+
+ if (copy_from_user(&input, (void __user *)argp->data, sizeof(input)))
+ return -EFAULT;
+
+ data = kzalloc(sizeof(*data), GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+
+ /* userspace wants to query CSR length */
+ if (!input.address || !input.length)
+ goto cmd;
+
+ /* allocate a physically contiguous buffer to store the CSR blob */
+ if (!access_ok(VERIFY_WRITE, input.address, input.length) ||
+ input.length > SEV_FW_BLOB_MAX_SIZE) {
+ ret = -EFAULT;
+ goto e_free;
+ }
+
+ blob = kmalloc(input.length, GFP_KERNEL);
+ if (!blob) {
+ ret = -ENOMEM;
+ goto e_free;
+ }
+
+ data->address = __psp_pa(blob);
+ data->len = input.length;
+
+cmd:
+ ret = sev_platform_init(NULL, &argp->error);
+ if (ret)
+ goto e_free_blob;
+
+ ret = sev_do_cmd(SEV_CMD_PEK_CSR, data, &argp->error);
+
+ /*
+ * If we query the CSR length, FW responded with expected data
+ */
+ input.length = data->len;
+
+ if (sev_platform_shutdown(&err)) {
+ /*
+ * If both sev_do_cmd() and sev_platform_shutdown() commands
+ * failed then propogate the error code from the sev_do_cmd()
+ * because it contains a useful status code for the command
+ * failure.
+ */
+ if (ret)
+ goto e_free_blob;
+
+ ret = -EIO;
+ argp->error = err;
+ goto e_free_blob;
+ }
+
+ if (copy_to_user((void __user *)argp->data, &input, sizeof(input))) {
+ ret = -EFAULT;
+ goto e_free_blob;
+ }
+
+ if (blob) {
+ if (copy_to_user((void __user *)input.address, blob, input.length))
+ ret = -EFAULT;
+ }
+
+e_free_blob:
+ kfree(blob);
+e_free:
+ kfree(data);
+ return ret;
+}
+
static long sev_ioctl(struct file *file, unsigned int ioctl, unsigned long arg)
{
void __user *argp = (void __user *)arg;
@@ -252,6 +330,9 @@ static long sev_ioctl(struct file *file, unsigned int ioctl, unsigned long arg)
case SEV_PDH_GEN:
ret = sev_ioctl_do_pek_pdh_gen(SEV_CMD_PDH_GEN, &input);
break;
+ case SEV_PEK_CSR:
+ ret = sev_ioctl_do_pek_csr(&input);
+ break;
default:
ret = -EINVAL;
goto out;
--
2.9.5