From 51d8d6d0f4bedb6a4e9afb20857bb592424de144 Mon Sep 17 00:00:00 2001
From: Herbert Xu <herbert@gondor.apana.org.au>
Date: Fri, 19 May 2023 16:28:35 +0800
Subject: [PATCH] crypto: cipher - Add crypto_clone_cipher
Allow simple ciphers to be cloned, if they don't have a cra_init
function. This basically rules out those ciphers that require a
fallback.
In future simple ciphers will be eliminated, and replaced with a
linear skcipher interface. When that happens this restriction will
disappear.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
---
crypto/cipher.c | 23 +++++++++++++++++++++++
include/crypto/internal/cipher.h | 2 ++
2 files changed, 25 insertions(+)
diff --git a/crypto/cipher.c b/crypto/cipher.c
index b47141ed4a9f3..d39ef5f72ab86 100644
--- a/crypto/cipher.c
+++ b/crypto/cipher.c
@@ -90,3 +90,26 @@ void crypto_cipher_decrypt_one(struct crypto_cipher *tfm,
cipher_crypt_one(tfm, dst, src, false);
}
EXPORT_SYMBOL_NS_GPL(crypto_cipher_decrypt_one, CRYPTO_INTERNAL);
+
+struct crypto_cipher *crypto_clone_cipher(struct crypto_cipher *cipher)
+{
+ struct crypto_tfm *tfm = crypto_cipher_tfm(cipher);
+ struct crypto_alg *alg = tfm->__crt_alg;
+ struct crypto_cipher *ncipher;
+ struct crypto_tfm *ntfm;
+
+ if (alg->cra_init)
+ return ERR_PTR(-ENOSYS);
+
+ ntfm = __crypto_alloc_tfm(alg, CRYPTO_ALG_TYPE_CIPHER,
+ CRYPTO_ALG_TYPE_MASK);
+ if (IS_ERR(ntfm))
+ return ERR_CAST(ntfm);
+
+ ntfm->crt_flags = tfm->crt_flags;
+
+ ncipher = __crypto_cipher_cast(ntfm);
+
+ return ncipher;
+}
+EXPORT_SYMBOL_GPL(crypto_clone_cipher);
diff --git a/include/crypto/internal/cipher.h b/include/crypto/internal/cipher.h
index a9174ba902500..5030f6d2df315 100644
--- a/include/crypto/internal/cipher.h
+++ b/include/crypto/internal/cipher.h
@@ -176,6 +176,8 @@ void crypto_cipher_encrypt_one(struct crypto_cipher *tfm,
void crypto_cipher_decrypt_one(struct crypto_cipher *tfm,
u8 *dst, const u8 *src);
+struct crypto_cipher *crypto_clone_cipher(struct crypto_cipher *cipher);
+
struct crypto_cipher_spawn {
struct crypto_spawn base;
};
--
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