linux-kernel - Re: [PATCH v5 2/3] tpm: enhance read_log_of() to support Physical TPM event log

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Message-ID: <20161123193700.GA13927@obsidianresearch.com>
Date:   Wed, 23 Nov 2016 12:37:00 -0700
From:   Jason Gunthorpe <jgunthorpe@...idianresearch.com>
To:     Nayna Jain <nayna@...ux.vnet.ibm.com>
Cc:     tpmdd-devel@...ts.sourceforge.net, peterhuewe@....de,
        tpmdd@...horst.net, jarkko.sakkinen@...ux.intel.com,
        linux-security-module@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v5 2/3] tpm: enhance read_log_of() to support Physical
 TPM event log

On Wed, Nov 23, 2016 at 12:27:36PM -0500, Nayna Jain wrote:
>  	sizep = of_get_property(np, "linux,sml-size", NULL);
> +	if (of_property_match_string(np, "compatible", "IBM,vtpm") < 0)
> +		log_size = be32_to_cpup(sizep);
> +	else
> +		log_size = *sizep;
> +

Uh, no, sizep can be null at this point:

>  	basep = of_get_property(np, "linux,sml-base", NULL);
>  	if (sizep == NULL && basep == NULL)
>  		return -ENODEV;
>  	if (sizep == NULL || basep == NULL)
>  		return -EIO;

Move the if here.

> -	if (*sizep == 0) {
> +	if (log_size == 0) {
>  		dev_warn(&chip->dev, "%s: Event log area empty\n", __func__);
>  		return -EIO;
>  	}
>  
> -	log->bios_event_log = kmalloc(*sizep, GFP_KERNEL);
> +	log->bios_event_log = kmalloc(log_size, GFP_KERNEL);
>  	if (!log->bios_event_log)
>  		return -ENOMEM;
>  
> -	log->bios_event_log_end = log->bios_event_log + *sizep;
> +	log->bios_event_log_end = log->bios_event_log + log_size;
>  
> -	memcpy(log->bios_event_log, __va(*basep), *sizep);
> +	if (of_property_match_string(np, "compatible", "IBM,vtpm") < 0)
> +		memcpy(chip->log.bios_event_log, __va(be64_to_cpup(basep)),
> +		       log_size);
> +	else
> +		memcpy(chip->log.bios_event_log, __va(*basep),
> log_size);

And move the conditional swap of basep up to be along side sizep as
well (ie get rid of the second of_property_match_string)

Jason