Re: [PATCH v2 2/6] crypto: lib/sha256 - Don't clear temporary variables

2020-10-22 Thread Arvind Sankar
On Wed, Oct 21, 2020 at 09:58:50PM -0700, Eric Biggers wrote: > On Tue, Oct 20, 2020 at 04:39:53PM -0400, Arvind Sankar wrote: > > The assignments to clear a through h and t1/t2 are optimized out by the > > compiler because they are unused after the assignments. > > > > These variables shouldn't

Re: [PATCH v2 2/6] crypto: lib/sha256 - Don't clear temporary variables

2020-10-21 Thread Eric Biggers
On Tue, Oct 20, 2020 at 04:39:53PM -0400, Arvind Sankar wrote: > The assignments to clear a through h and t1/t2 are optimized out by the > compiler because they are unused after the assignments. > > These variables shouldn't be very sensitive: t1/t2 can be calculated > from a through h, so they

[PATCH v2 2/6] crypto: lib/sha256 - Don't clear temporary variables

2020-10-20 Thread Arvind Sankar
The assignments to clear a through h and t1/t2 are optimized out by the compiler because they are unused after the assignments. These variables shouldn't be very sensitive: t1/t2 can be calculated from a through h, so they don't reveal any additional information. Knowing a through h is equivalent