Thread (18 messages) 18 messages, 3 authors, 2021-05-21
STALE1848d
Revisions (7)
  1. rfc [diff vs current]
  2. v2 [diff vs current]
  3. v3 current
  4. v4 [diff vs current]
  5. v5 [diff vs current]
  6. v6 [diff vs current]
  7. v7 [diff vs current]

[PATCH v3 3/7] crypto: skcipher - disallow en/decrypt for non-task or non-softirq context

From: Ard Biesheuvel <ardb@kernel.org>
Date: 2021-05-12 21:08:10
Also in: linux-crypto
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 | 10 ++++++++++
 1 file changed, 10 insertions(+)
diff --git a/crypto/skcipher.c b/crypto/skcipher.c
index 93fdacf49697..9bce5350008b 100644
--- a/crypto/skcipher.c
+++ b/crypto/skcipher.c
@@ -625,6 +625,11 @@ 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;
@@ -642,6 +647,11 @@ 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;
-- 
2.20.1


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