On 1/25/2019 3:48 PM, Herbert Xu wrote:
> On Fri, Jan 25, 2019 at 12:43:21PM +0000, Horia Geanta wrote:
>>
>> Herbert, is there something we could do to avoid this?
>
> Async crypto requests cannot be allocated off the stack. So
> whoever is doing this needs to stop.
>
IIUC, the crypto request is allocated in ima_calc_file_hash_atfm() using
ahash_request_alloc(), so this seems to be fine.
However, further below the req->result pointer is set to a location on stack:
out2:
if (!rc) {
ahash_request_set_crypt(req, NULL, hash->digest, 0);
More exactly, the call sequence is:
ima_collect_measurement() -> ima_calc_file_hash() -> ima_calc_file_ahash() ->
ima_calc_file_hash_atfm()
and "hash" is allocated on stack in ima_collect_measurement().
Thus, it seems the problem lies in the fact that ahash_request structure defines
the digest buffer as "u8 *result" - thus the memory area might not be DMAable.
Thanks,
Horia
