On Thu, May 11, 2017 at 11:09 AM, Eric Biggers <ebiggers3@xxxxxxxxx> wrote: > On Thu, May 11, 2017 at 10:29:47AM +0300, Gilad Ben-Yossef wrote: >> > With regards to the wait being uninterruptible, I agree that this should be the >> > default behavior, because I think users waiting for specific crypto requests are >> > generally not prepared to handle the wait actually being interrupted. After >> > interruption the crypto operation will still proceed in the background, and it >> > will use buffers which the caller has in many cases already freed. However, I'd >> > suggest taking a close look at anything that was actually doing an interruptible >> > wait before, to see whether it was a bug or intentional (or "doesn't matter"). >> > >> > And yes there could always be a crypto_wait_req_interruptible() introduced if >> > some users need it. >> >> So this one was a bit of a shocker. I though the _interruptible use >> sites seemed >> wrong in the sense of being needless. However, after reading your feedback and >> reviewing the code I'm pretty sure every single one of them (including >> the one I've >> added in dm-verity-target.c this merge window) are down right dangerous and >> can cause random data corruption... so thanks for pointing this out! >> >> I though of this patch set as a "make the code pretty" for 4.13 kind >> of patch set. >> Looks like it's a bug fix now, maybe even stable material. >> >> Anyway, I'll roll a v2 and we'll see. >> > > Any that are called only by kernel threads would theoretically be safe since > kernel threads don't ordinarily receive signals. But I think that at least the > drbg and gcm waits can be reached by user threads, since they can be called via > algif_rng and algif_aead respectively. > > I recommend putting any important fixes first, so they can be backported without > depending on crypto_wait_req(). > OK, I'll send out a separate bug fix series first and rebase the crypto_wait one on top of it then. Thanks, Gilad -- Gilad Ben-Yossef Chief Coffee Drinker "If you take a class in large-scale robotics, can you end up in a situation where the homework eats your dog?" -- Jean-Baptiste Queru
