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SubjectRe: [Part2 PATCH v5.1 12.7/31] crypto: ccp: Implement SEV_PEK_CSR ioctl command
On Fri, Oct 06, 2017 at 08:06:05PM -0500, Brijesh Singh wrote:
> 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@redhat.com>
> Cc: "Radim Krčmář" <rkrcmar@redhat.com>
> Cc: Borislav Petkov <bp@suse.de>
> Cc: Herbert Xu <herbert@gondor.apana.org.au>
> Cc: Gary Hook <gary.hook@amd.com>
> Cc: Tom Lendacky <thomas.lendacky@amd.com>
> Cc: linux-crypto@vger.kernel.org
> Cc: kvm@vger.kernel.org
> Cc: linux-kernel@vger.kernel.org
> Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
> ---
> drivers/crypto/ccp/psp-dev.c | 85 ++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 85 insertions(+)

Ok, a couple of things here:

* Move the checks first and the allocations second so that you allocate
memory only after all checks have been passed and you don't allocate
pointlessly.

* That:

if (state == SEV_STATE_WORKING) {
ret = -EBUSY;
goto e_free_blob;
} else if (state == SEV_STATE_UNINIT) {
ret = sev_firmware_init(&argp->error);
if (ret)
goto e_free_blob;
do_shutdown = 1;
}

is a repeating pattern. Perhaps it should be called
sev_firmware_reinit() and called by other functions.

* The rest is simplifications and streamlining.

---
diff --git a/drivers/crypto/ccp/psp-dev.c b/drivers/crypto/ccp/psp-dev.c
index e3ee68afd068..d41f5448a25b 100644
--- a/drivers/crypto/ccp/psp-dev.c
+++ b/drivers/crypto/ccp/psp-dev.c
@@ -302,33 +302,30 @@ static int sev_ioctl_pek_csr(struct sev_issue_cmd *argp)
int ret, state;
void *blob;

- if (copy_from_user(&input, (void __user *)(uintptr_t)argp->data,
- sizeof(struct sev_user_data_pek_csr)))
+ if (copy_from_user(&input, (void __user *)argp->data, sizeof(input)))
+ return -EFAULT;
+
+ if (!input.address)
+ return -EINVAL;
+
+ /* 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)
return -EFAULT;

data = kzalloc(sizeof(*data), GFP_KERNEL);
if (!data)
return -ENOMEM;

- /* allocate a temporary physical contigous buffer to store the CSR blob */
- blob = NULL;
- if (input.address) {
- 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;
+ blob = kmalloc(input.length, GFP_KERNEL);
+ if (!blob) {
+ ret = -ENOMEM;
+ goto e_free;
}

+ data->address = __psp_pa(blob);
+ data->len = input.length;
+
ret = sev_platform_get_state(&state, &argp->error);
if (ret)
goto e_free_blob;
@@ -349,25 +346,23 @@ static int sev_ioctl_pek_csr(struct sev_issue_cmd *argp)
do_shutdown = 1;
}

- ret = sev_handle_cmd(SEV_CMD_PEK_CSR, data, &argp->error);
+ ret = sev_do_cmd(SEV_CMD_PEK_CSR, data, &argp->error);

input.length = data->len;

/* copy blob to userspace */
- if (blob &&
- copy_to_user((void __user *)(uintptr_t)input.address,
- blob, input.length)) {
+ if (copy_to_user((void __user *)input.address, blob, input.length)) {
ret = -EFAULT;
goto e_shutdown;
}

- if (copy_to_user((void __user *)(uintptr_t)argp->data, &input,
- sizeof(struct sev_user_data_pek_csr)))
+ if (copy_to_user((void __user *)argp->data, &input, sizeof(input)))
ret = -EFAULT;

e_shutdown:
if (do_shutdown)
- sev_handle_cmd(SEV_CMD_SHUTDOWN, 0, NULL);
+ ret = sev_do_cmd(SEV_CMD_SHUTDOWN, 0, NULL);
+
e_free_blob:
kfree(blob);
e_free:
@@ -408,10 +403,10 @@ static long sev_ioctl(struct file *file, unsigned int ioctl, unsigned long arg)
ret = sev_ioctl_pdh_gen(&input);
break;

- case SEV_PEK_CSR: {
+ case SEV_PEK_CSR:
ret = sev_ioctl_pek_csr(&input);
break;
- }
+
default:
ret = -EINVAL;
goto out;
--
Regards/Gruss,
Boris.

SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
--

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