[PATCH] ima: dynamically allocate shash_desc

[Mimi Zohar]

On Mon, 2019-06-17 at 11:55 -0400, Mimi Zohar wrote:
> On Mon, 2019-06-17 at 13:20 +0200, Arnd Bergmann wrote:
> > On 32-bit ARM, we get a warning about excessive stack usage when
> > building with clang.
> > 
> > security/integrity/ima/ima_crypto.c:504:5: error: stack frame size
> > of 1152 bytes in function 'ima_calc_field_array_hash' [-Werror,-
> > Wframe-larger-than=]
> 
> I'm definitely not seeing this.  Is this problem a result of non
> upstreamed patches?  For sha1, currently the only possible hash
> algorithm, I'm seeing 664.

Every time a measurement is added to the measurement list, the memory
would be allocated/freed.  The frequency of new measurements is policy
dependent.  For performance reasons, I'd prefer if the allocation
remains on the stack.

Mimi