Re: [Part2 PATCH v6 16/38] crypto: ccp: Implement SEV_PEK_GEN ioctl command

[Brijesh Singh <brijesh.singh@amd.com>]

On 10/23/17 4:32 AM, Borislav Petkov wrote:
...
>> +static int sev_ioctl_do_pek_pdh_gen(int cmd, struct sev_issue_cmd *argp)
>> +{
>> +	int ret, err;
>> +
>> +	ret = sev_platform_init(NULL, &argp->error);
>> +	if (ret)
>> +		return ret;
>> +
>> +	ret = sev_do_cmd(cmd, 0, &argp->error);
> So this ret value gets potentially overwritten here. You need
> to either handle the case properly when sev_do_cmd() fails and
> sev_platform_shutdown() gets to issue SEV_CMD_SHUTDOWN (i.e., when it
> gets overwritten), or not write into ret at all by initializing it to 0
> at function entry.
>

I am not sure if I am able to understand your feedback. The
sev_platform_shutdown() is called unconditionally.

1) if sev_do_cmd() fails and sev_platform_shutdown() was success then
'ret' will contain the  error code from sev_do_cmd().
2) if sev_do_cmd() was success but sev_platform_shutdown() fails then
'ret' will contain the error code from sev_platform_shutdown()
3) if both sev_do_cmd() and sev_platform_shutdown() fails then 'ret'
will contain error code from the sev_platform_shutdown().