linux-kernel - Re: [PATCH] ima: avoid appraise error for hash calc interrupt

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Message-Id: <1573578841.17949.48.camel@linux.ibm.com>
Date:   Tue, 12 Nov 2019 12:14:01 -0500
From:   Mimi Zohar <zohar@...ux.ibm.com>
To:     Lakshmi Ramasubramanian <nramas@...ux.microsoft.com>,
        Patrick Callaghan <patrickc@...ux.ibm.com>,
        linux-integrity@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org, Sascha Hauer <s.hauer@...gutronix.de>
Subject: Re: [PATCH] ima: avoid appraise error for hash calc interrupt

On Mon, 2019-11-11 at 14:29 -0800, Lakshmi Ramasubramanian wrote:
> On 11/11/19 11:23 AM, Patrick Callaghan wrote:
> 
> > -		if (rbuf_len == 0)
> > +		if (rbuf_len == 0) {	/* unexpected EOF */
> > +			rc = -EINVAL;
> >   			break;
> > +		}
> >   		offset += rbuf_len;
> 
> Should there be an additional check to validate that (offset + rbuf_len) 
> is less than i_size before calling cypto_shash_update (since rbuf_len is 
> one of the parameters for this call)?

The "while" statement enforces that.

Mimi

> 
>                 if ((rbuf_len == 0) || (offset + rbuf_len >= i_size)) {
>                          rc = -EINVAL;
>                          break;
>                 }
>                 offset += rbuf_len;
> 
> >   	       rc = crypto_shash_update(shash, rbuf, rbuf_len);
> 
>   -lakshmi
>