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SubjectRe: [PATCH] ima: avoid appraise error for hash calc interrupt
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On Tue, 2019-11-12 at 09:33 -0800, Lakshmi Ramasubramanian wrote:
> On 11/12/2019 9:14 AM, Mimi Zohar wrote:
>
> > 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
>
> Yes - but that check happens after the call to crypto_shash_update().
>
> Perhaps integrity_kernel_read() will never return (rbuf_len) that will
> => violate the check in the "while" statement.
> => number of bytes read that is greater than the memory allocated for
> rbuf even in error conditions.
>
> Just making sure.

integrity_kernel_read() returns an error (< 0) or the number of bytes
read.  The while statement ensures that there is more data to read, so
returning 0 is always an error.

Mimi

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