On 6 September 2018 at 10:51, Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> wrote: > On Thu, Sep 06, 2018 at 10:11:59AM +0200, Ard Biesheuvel wrote: >> >> That way, we will almost certainly oops on a NULL pointer dereference >> right after, but we at least the stack corruption. > > A crash is just as bad as a BUG_ON. > > Is this even a real problem? Do we have any users of this construct > that is using it on async algorithms? > Perhaps not, but it is not enforced atm. In any case, limiting the reqsize is going to break things, so that needs to occur based on the sync/async nature of the algo. That also means we'll corrupt the stack if we ever end up using SKCIPHER_REQUEST_ON_STACK() with an async algo whose reqsize is greater than the sync reqsize limit, so I do think some additional sanity check is appropriate.
