| Message ID | 20210519112239.33664-3-ardb@kernel.org |
|---|---|
| State | New |
| Headers | show |
| Series | running kernel mode SIMD with softirqs disabled | expand |
On Wed, May 19, 2021 at 01:22:34PM +0200, Ard Biesheuvel wrote: > > crypto_stats_get(alg); > - if (crypto_aead_get_flags(aead) & CRYPTO_TFM_NEED_KEY) > + if (!(alg->cra_flags & CRYPTO_ALG_ASYNC) && > + WARN_ONCE(!in_task() && !in_serving_softirq(), > + "synchronous call from invalid context\n")) > + ret = -EBUSY; I don't think we've ever supported crypto in hard IRQ contexts. So this should be done regardless of ASYNC. Then again, do we really need this since the assumption has always been that the crypto API can only be invoked in user or softirq context? Cheers,
On Wed, May 19, 2021 at 01:36:37PM +0200, Ard Biesheuvel wrote: > > So if we do need to check this, we should check it here. If we don't, > then we can drop these patches. Historically other things would break in nasty ways if you tried to do crypto in hard IRQ contexts, e.g., overwritten kmap slots back when we had individual slots for each context, but I don't think we've ever found anyone crazy enough to do that to warrant a run-time check. I'd just leave it out for now. Thanks,
On Wed, 19 May 2021 at 13:51, Herbert Xu <herbert@gondor.apana.org.au> wrote: > > On Wed, May 19, 2021 at 01:36:37PM +0200, Ard Biesheuvel wrote: > > > > So if we do need to check this, we should check it here. If we don't, > > then we can drop these patches. > > Historically other things would break in nasty ways if you tried > to do crypto in hard IRQ contexts, e.g., overwritten kmap slots > back when we had individual slots for each context, but I don't > think we've ever found anyone crazy enough to do that to warrant > a run-time check. > > I'd just leave it out for now. > Fair enough. Would you like me to resend the series with these patches left out Or are you ok to just take the remaining ones (assuming there are no issues reported with those)?
diff --git a/crypto/aead.c b/crypto/aead.c index 16991095270d..141c9369b02a 100644 --- a/crypto/aead.c +++ b/crypto/aead.c @@ -88,7 +88,11 @@ int crypto_aead_encrypt(struct aead_request *req) int ret; crypto_stats_get(alg); - if (crypto_aead_get_flags(aead) & CRYPTO_TFM_NEED_KEY) + if (!(alg->cra_flags & CRYPTO_ALG_ASYNC) && + WARN_ONCE(!in_task() && !in_serving_softirq(), + "synchronous call from invalid context\n")) + ret = -EBUSY; + else if (crypto_aead_get_flags(aead) & CRYPTO_TFM_NEED_KEY) ret = -ENOKEY; else ret = crypto_aead_alg(aead)->encrypt(req); @@ -105,7 +109,11 @@ int crypto_aead_decrypt(struct aead_request *req) int ret; crypto_stats_get(alg); - if (crypto_aead_get_flags(aead) & CRYPTO_TFM_NEED_KEY) + if (!(alg->cra_flags & CRYPTO_ALG_ASYNC) && + WARN_ONCE(!in_task() && !in_serving_softirq(), + "synchronous call from invalid context\n")) + ret = -EBUSY; + else if (crypto_aead_get_flags(aead) & CRYPTO_TFM_NEED_KEY) ret = -ENOKEY; else if (req->cryptlen < crypto_aead_authsize(aead)) ret = -EINVAL;
In order to ensure that kernel mode SIMD routines will not need a scalar fallback if they run with softirqs disabled, disallow any use of the AEAD encrypt and decrypt routines from outside of task or softirq context. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> --- crypto/aead.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-)