On Wed, Nov 01, 2017 at 04:16:05PM -0500, Brijesh Singh wrote:
> The SEV_PDH_CERT_EXPORT command can be used to export the PDH and its
> certificate chain. The command is defined in SEV spec section 5.10.

...

> ---
>  drivers/crypto/ccp/psp-dev.c | 98 
> ++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 98 insertions(+)

Fixes ontop:

* !input.cert_chain_address test was repeated. I saw that by aligning
them vertically, i.e., after making it more readable, the repetition
became obvious.

* Do the lengths checks first and the access_ok after, in each PDH and
cert chain test.

* Do the checks first and the allocations after, not interleaved.

* Comments are sentences which should end with a '.'

(hunk below contains also that &psp_master->cmd_buf change but you're going to
 remove that arg anyway).

---
diff --git a/drivers/crypto/ccp/psp-dev.c b/drivers/crypto/ccp/psp-dev.c
index 09f69e573d00..d3fdcce61e6d 100644
--- a/drivers/crypto/ccp/psp-dev.c
+++ b/drivers/crypto/ccp/psp-dev.c
@@ -455,14 +455,22 @@ static int sev_ioctl_do_pdh_export(struct sev_issue_cmd 
*argp)
        if (!data)
                return -ENOMEM;
 
-       /* Userspace wants to query the certificate length */
-       if (!input.pdh_cert_address || !input.pdh_cert_len ||
-           !input.cert_chain_address || !input.cert_chain_address)
+       /* Userspace wants to query the certificate length. */
+       if (!input.pdh_cert_address ||
+           !input.pdh_cert_len ||
+           !input.cert_chain_address)
                goto cmd;
 
-       /* allocate a physically contiguous buffer to store the PDH blob */
-       if (!access_ok(VERIFY_WRITE, input.pdh_cert_address, 
input.pdh_cert_len) ||
-           (input.pdh_cert_len > SEV_FW_BLOB_MAX_SIZE)) {
+       /* allocate a physically contiguous buffer to store the PDH blob. */
+       if ((input.pdh_cert_len > SEV_FW_BLOB_MAX_SIZE) ||
+           !access_ok(VERIFY_WRITE, input.pdh_cert_address, 
input.pdh_cert_len)) {
+               ret = -EFAULT;
+               goto e_free;
+       }
+
+       /* allocate a physically contiguous buffer to store the cert chain 
blob. */
+       if ((input.cert_chain_len > SEV_FW_BLOB_MAX_SIZE) ||
+           !access_ok(VERIFY_WRITE, input.cert_chain_address, 
input.cert_chain_len)) {
                ret = -EFAULT;
                goto e_free;
        }
@@ -476,13 +484,6 @@ static int sev_ioctl_do_pdh_export(struct sev_issue_cmd 
*argp)
        data->pdh_cert_address = __psp_pa(pdh_blob);
        data->pdh_cert_len = input.pdh_cert_len;
 
-       /* allocate a physically contiguous buffer to store the cert chain blob 
*/
-       if (!access_ok(VERIFY_WRITE, input.cert_chain_address, 
input.cert_chain_len) ||
-           (input.cert_chain_len > SEV_FW_BLOB_MAX_SIZE)) {
-               ret = -EFAULT;
-               goto e_free_pdh;
-       }
-
        cert_blob = kmalloc(input.cert_chain_len, GFP_KERNEL);
        if (!cert_blob) {
                ret = -ENOMEM;
@@ -493,18 +494,16 @@ static int sev_ioctl_do_pdh_export(struct sev_issue_cmd 
*argp)
        data->cert_chain_len = input.cert_chain_len;
 
 cmd:
-       /* If platform is not in INIT state then transition it to INIT */
+       /* If platform is not in INIT state then transition it to INIT. */
        if (psp_master->sev_state != SEV_STATE_INIT) {
-               ret = __sev_platform_init_locked(psp_master->sev_init, 
&argp->error);
+               ret = __sev_platform_init_locked(&psp_master->cmd_buf, 
&argp->error);
                if (ret)
                        goto e_free_cert;
        }
 
        ret = __sev_do_cmd_locked(SEV_CMD_PDH_CERT_EXPORT, data, &argp->error);
 
-       /*
-        * If we query the length, FW responded with expected data
-        */
+       /* If we query the length, FW responded with expected data. */
        input.cert_chain_len = data->cert_chain_len;
        input.pdh_cert_len = data->pdh_cert_len;
 

-- 
Regards/Gruss,
    Boris.

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