[RFC PATCH 2/5] crypto: skcipher - disallow en/decrypt for non-task or non-softirq context
From: Ard Biesheuvel
Date: Fri Dec 18 2020 - 12:04:03 EST
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
skcipher encrypt and decrypt routines from outside of task or softirq
context.
Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx>
---
crypto/skcipher.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/crypto/skcipher.c b/crypto/skcipher.c
index b4dae640de9f..d1a656d7d498 100644
--- a/crypto/skcipher.c
+++ b/crypto/skcipher.c
@@ -628,6 +628,11 @@ int crypto_skcipher_encrypt(struct skcipher_request *req)
unsigned int cryptlen = req->cryptlen;
int ret;
+ if (!(alg->cra_flags & CRYPTO_ALG_ASYNC) &&
+ WARN_ONCE(!in_task() && !in_serving_softirq(),
+ "synchronous call from invalid context\n"))
+ return -EBUSY;
+
crypto_stats_get(alg);
if (crypto_skcipher_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
ret = -ENOKEY;
@@ -645,6 +650,11 @@ int crypto_skcipher_decrypt(struct skcipher_request *req)
unsigned int cryptlen = req->cryptlen;
int ret;
+ if (!(alg->cra_flags & CRYPTO_ALG_ASYNC) &&
+ WARN_ONCE(!in_task() && !in_serving_softirq(),
+ "synchronous call from invalid context\n"))
+ return -EBUSY;
+
crypto_stats_get(alg);
if (crypto_skcipher_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
ret = -ENOKEY;
--
2.17.1