[PATCH v4 3/7] crypto: skcipher - disallow en/decrypt for non-task or non-softirq context
From: Ard Biesheuvel <ardb@kernel.org>
Date: 2021-05-19 11:23:00
Also in:
linux-arm-kernel
Subsystem:
crypto api, the rest · Maintainers:
Herbert Xu, "David S. Miller", Linus Torvalds
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@kernel.org> --- crypto/skcipher.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/crypto/skcipher.c b/crypto/skcipher.c
index ed2deb031742..f69492aab75d 100644
--- a/crypto/skcipher.c
+++ b/crypto/skcipher.c@@ -628,7 +628,11 @@ int crypto_skcipher_encrypt(struct skcipher_request *req) int ret; crypto_stats_get(alg); - if (crypto_skcipher_get_flags(tfm) & 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_skcipher_get_flags(tfm) & CRYPTO_TFM_NEED_KEY) ret = -ENOKEY; else ret = crypto_skcipher_alg(tfm)->encrypt(req);
@@ -645,7 +649,11 @@ int crypto_skcipher_decrypt(struct skcipher_request *req) int ret; crypto_stats_get(alg); - if (crypto_skcipher_get_flags(tfm) & 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_skcipher_get_flags(tfm) & CRYPTO_TFM_NEED_KEY) ret = -ENOKEY; else ret = crypto_skcipher_alg(tfm)->decrypt(req);
--
2.20.1