crypto: arm64/aes-bs - implement non-SIMD fallback for AES-CTR

Of the various chaining modes implemented by the bit sliced AES driver,
only CTR is exposed as a synchronous cipher, and requires a fallback in
order to remain usable once we update the kernel mode NEON handling logic
to disallow nested use. So wire up the existing CTR fallback C code.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/arch/arm64/crypto/Kconfig b/arch/arm64/crypto/Kconfig
index a068dcbe25187996ca28c2c36db48a77f9f195d8..f9e264b8336642cbaddbcfdb2b14b40e2b39d34f 100644 (file)
--- a/arch/arm64/crypto/Kconfig
+++ b/arch/arm64/crypto/Kconfig
@@ -89,6 +89,7 @@ config CRYPTO_AES_ARM64_BS
        depends on KERNEL_MODE_NEON
        select CRYPTO_BLKCIPHER
        select CRYPTO_AES_ARM64_NEON_BLK
+       select CRYPTO_AES_ARM64
        select CRYPTO_SIMD
 
 endif

diff --git a/arch/arm64/crypto/aes-neonbs-glue.c b/arch/arm64/crypto/aes-neonbs-glue.c
index 9001aec16007bedb5212af86a2cb4f753a296df4..c55d68ccb89f804a7db201ae23abe49ace0a1188 100644 (file)
--- a/arch/arm64/crypto/aes-neonbs-glue.c
+++ b/arch/arm64/crypto/aes-neonbs-glue.c
@@ -1,7 +1,7 @@
 /*
  * Bit sliced AES using NEON instructions
  *
- * Copyright (C) 2016 Linaro Ltd <ard.biesheuvel@linaro.org>
+ * Copyright (C) 2016 - 2017 Linaro Ltd <ard.biesheuvel@linaro.org>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
@@ -9,12 +9,15 @@
  */
 
 #include <asm/neon.h>
+#include <asm/simd.h>
 #include <crypto/aes.h>
 #include <crypto/internal/simd.h>
 #include <crypto/internal/skcipher.h>
 #include <crypto/xts.h>
 #include <linux/module.h>
 
+#include "aes-ctr-fallback.h"
+
 MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
 MODULE_LICENSE("GPL v2");
 
@@ -58,6 +61,11 @@ struct aesbs_cbc_ctx {
        u32                     enc[AES_MAX_KEYLENGTH_U32];
 };
 
+struct aesbs_ctr_ctx {
+       struct aesbs_ctx        key;            /* must be first member */
+       struct crypto_aes_ctx   fallback;
+};
+
 struct aesbs_xts_ctx {
        struct aesbs_ctx        key;
        u32                     twkey[AES_MAX_KEYLENGTH_U32];
@@ -196,6 +204,25 @@ static int cbc_decrypt(struct skcipher_request *req)
        return err;
 }
 
+static int aesbs_ctr_setkey_sync(struct crypto_skcipher *tfm, const u8 *in_key,
+                                unsigned int key_len)
+{
+       struct aesbs_ctr_ctx *ctx = crypto_skcipher_ctx(tfm);
+       int err;
+
+       err = crypto_aes_expand_key(&ctx->fallback, in_key, key_len);
+       if (err)
+               return err;
+
+       ctx->key.rounds = 6 + key_len / 4;
+
+       kernel_neon_begin();
+       aesbs_convert_key(ctx->key.rk, ctx->fallback.key_enc, ctx->key.rounds);
+       kernel_neon_end();
+
+       return 0;
+}
+
 static int ctr_encrypt(struct skcipher_request *req)
 {
        struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
@@ -259,6 +286,17 @@ static int aesbs_xts_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
        return aesbs_setkey(tfm, in_key, key_len);
 }
 
+static int ctr_encrypt_sync(struct skcipher_request *req)
+{
+       struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
+       struct aesbs_ctr_ctx *ctx = crypto_skcipher_ctx(tfm);
+
+       if (!may_use_simd())
+               return aes_ctr_encrypt_fallback(&ctx->fallback, req);
+
+       return ctr_encrypt(req);
+}
+
 static int __xts_crypt(struct skcipher_request *req,
                       void (*fn)(u8 out[], u8 const in[], u8 const rk[],
                                  int rounds, int blocks, u8 iv[]))
@@ -355,7 +393,7 @@ static struct skcipher_alg aes_algs[] = { {
        .base.cra_driver_name   = "ctr-aes-neonbs",
        .base.cra_priority      = 250 - 1,
        .base.cra_blocksize     = 1,
-       .base.cra_ctxsize       = sizeof(struct aesbs_ctx),
+       .base.cra_ctxsize       = sizeof(struct aesbs_ctr_ctx),
        .base.cra_module        = THIS_MODULE,
 
        .min_keysize            = AES_MIN_KEY_SIZE,
@@ -363,9 +401,9 @@ static struct skcipher_alg aes_algs[] = { {
        .chunksize              = AES_BLOCK_SIZE,
        .walksize               = 8 * AES_BLOCK_SIZE,
        .ivsize                 = AES_BLOCK_SIZE,
-       .setkey                 = aesbs_setkey,
-       .encrypt                = ctr_encrypt,
-       .decrypt                = ctr_encrypt,
+       .setkey                 = aesbs_ctr_setkey_sync,
+       .encrypt                = ctr_encrypt_sync,
+       .decrypt                = ctr_encrypt_sync,
 }, {
        .base.cra_name          = "__xts(aes)",
        .base.cra_driver_name   = "__xts-aes-neonbs",