Messages in this thread | | | Date | Fri, 13 Oct 2017 11:14:37 +0200 | From | Borislav Petkov <> | Subject | Re: [Part2 PATCH v5.1 12.7/31] crypto: ccp: Implement SEV_PEK_CSR ioctl command |
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On Thu, Oct 12, 2017 at 09:24:01PM -0500, Brijesh Singh wrote: > I assume you mean performing the SEV state check before allocating the > memory for the CSR blob, right ?
I mean, do those first:
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;
Because if you allocate the memory first and some of those checks fail, you allocate in vain to free it immediately after. And you can save yourself all that.
-- Regards/Gruss, Boris.
SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg) --
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