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Date:   Thu, 26 Oct 2023 10:10:26 -0700
From:   Jerry Snitselaar <jsnitsel@redhat.com>
To:     Jarkko Sakkinen <jarkko@kernel.org>
Cc:     linux-integrity@vger.kernel.org, keyrings@vger.kernel.org,
        James Bottomley <James.Bottomley@hansenpartnership.com>,
        William Roberts <bill.c.roberts@gmail.com>,
        Stefan Berger <stefanb@linux.ibm.com>,
        David Howells <dhowells@redhat.com>,
        Jason Gunthorpe <jgg@ziepe.ca>,
        Mimi Zohar <zohar@linux.ibm.com>,
        Peter Huewe <peterhuewe@gmx.de>,
        Mario Limonciello <mario.limonciello@amd.com>,
        Julien Gomes <julien@arista.com>,
        open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v3 1/6] tpm: Move buffer handling from static inlines to
 real functions
Message-ID: <g6grxamrilogiy4vjrvwwn6iz2xm26oeq2y7redbskvcreil6w@seavf5djd4ph>
References: <20231024011531.442587-1-jarkko@kernel.org>
 <20231024011531.442587-2-jarkko@kernel.org>
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On Wed, Oct 25, 2023 at 08:35:55PM +0300, Jarkko Sakkinen wrote:
> On Wed Oct 25, 2023 at 12:03 PM EEST, Jerry Snitselaar wrote:
> > Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
> 
> On Wed, 2023-10-25 at 02:03 -0700, Jerry Snitselaar wrote:
> > Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
> >
> 
> Thanks I'll add it to the next round.
> 
> For the tpm_buf_read(), I was thinking along the lines of:
> 
> /**
>  * tpm_buf_read() - Read from a TPM buffer
>  * @buf:	&tpm_buf instance
>  * @pos:	position within the buffer
>  * @count:	the number of bytes to read
>  * @output:	the output buffer
>  *
>  * Read bytes from a TPM buffer, and update the position. Returns false when the
>  * amount of bytes requested would overflow the buffer, which is expected to
>  * only happen in the case of hardware failure.
>  */
> static bool tpm_buf_read(const struct tpm_buf *buf, off_t *pos, size_t count, void *output)
> {
> 	off_t next = *pos + count;
> 
> 	if (next >= buf->length) {
> 		pr_warn("%s: %lu >= %lu\n", __func__, next, *offset);
> 		return false;
> 	}
> 
> 	memcpy(output, &buf->data[*pos], count);
> 	*offset = next;
> 	return true;
> }
> 
> BR, Jarkko
> 

Then the callers will check, and return -EIO?