[PATCH] arm64/crypto: use crypto instructions for generating AES key schedule
Ard Biesheuvel
ard.biesheuvel at linaro.org
Wed Oct 22 00:15:32 PDT 2014
This patch implements the AES key schedule generation using ARMv8
Crypto Instructions. It replaces the table based C implementation
in aes_generic.ko, which means we can drop the dependency on that
module.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel at linaro.org>
---
arch/arm64/crypto/Kconfig | 5 +-
arch/arm64/crypto/aes-ce-ccm-glue.c | 4 +-
arch/arm64/crypto/aes-ce-cipher.c | 112 +++++++++++++++++++++++++++++++++++-
arch/arm64/crypto/aes-ce-setkey.h | 5 ++
arch/arm64/crypto/aes-glue.c | 18 ++++--
5 files changed, 133 insertions(+), 11 deletions(-)
create mode 100644 arch/arm64/crypto/aes-ce-setkey.h
diff --git a/arch/arm64/crypto/Kconfig b/arch/arm64/crypto/Kconfig
index 5562652c5316..a38b02ce5f9a 100644
--- a/arch/arm64/crypto/Kconfig
+++ b/arch/arm64/crypto/Kconfig
@@ -27,20 +27,19 @@ config CRYPTO_AES_ARM64_CE
tristate "AES core cipher using ARMv8 Crypto Extensions"
depends on ARM64 && KERNEL_MODE_NEON
select CRYPTO_ALGAPI
- select CRYPTO_AES
config CRYPTO_AES_ARM64_CE_CCM
tristate "AES in CCM mode using ARMv8 Crypto Extensions"
depends on ARM64 && KERNEL_MODE_NEON
select CRYPTO_ALGAPI
- select CRYPTO_AES
+ select CRYPTO_AES_ARM64_CE
select CRYPTO_AEAD
config CRYPTO_AES_ARM64_CE_BLK
tristate "AES in ECB/CBC/CTR/XTS modes using ARMv8 Crypto Extensions"
depends on ARM64 && KERNEL_MODE_NEON
select CRYPTO_BLKCIPHER
- select CRYPTO_AES
+ select CRYPTO_AES_ARM64_CE
select CRYPTO_ABLK_HELPER
config CRYPTO_AES_ARM64_NEON_BLK
diff --git a/arch/arm64/crypto/aes-ce-ccm-glue.c b/arch/arm64/crypto/aes-ce-ccm-glue.c
index 9e6cdde9b43d..0ac73b838fa3 100644
--- a/arch/arm64/crypto/aes-ce-ccm-glue.c
+++ b/arch/arm64/crypto/aes-ce-ccm-glue.c
@@ -16,6 +16,8 @@
#include <linux/crypto.h>
#include <linux/module.h>
+#include "aes-ce-setkey.h"
+
static int num_rounds(struct crypto_aes_ctx *ctx)
{
/*
@@ -48,7 +50,7 @@ static int ccm_setkey(struct crypto_aead *tfm, const u8 *in_key,
struct crypto_aes_ctx *ctx = crypto_aead_ctx(tfm);
int ret;
- ret = crypto_aes_expand_key(ctx, in_key, key_len);
+ ret = ce_aes_expandkey(ctx, in_key, key_len);
if (!ret)
return 0;
diff --git a/arch/arm64/crypto/aes-ce-cipher.c b/arch/arm64/crypto/aes-ce-cipher.c
index 2075e1acae6b..4207c83389d3 100644
--- a/arch/arm64/crypto/aes-ce-cipher.c
+++ b/arch/arm64/crypto/aes-ce-cipher.c
@@ -14,6 +14,8 @@
#include <linux/crypto.h>
#include <linux/module.h>
+#include "aes-ce-setkey.h"
+
MODULE_DESCRIPTION("Synchronous AES cipher using ARMv8 Crypto Extensions");
MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel at linaro.org>");
MODULE_LICENSE("GPL v2");
@@ -124,6 +126,114 @@ static void aes_cipher_decrypt(struct crypto_tfm *tfm, u8 dst[], u8 const src[])
kernel_neon_end();
}
+/*
+ * aes_sub() - use the aese instruction to perform the AES sbox substitution
+ * on each byte in 'input'
+ */
+static u32 aes_sub(u32 input)
+{
+ u32 ret;
+
+ __asm__("dup v1.4s, %w[in] ;"
+ "movi v0.16b, #0 ;"
+ "aese v0.16b, v1.16b ;"
+ "umov %w[out], v0.4s[0] ;"
+
+ : [out] "=r"(ret)
+ : [in] "r"(input)
+ : "v0","v1");
+
+ return ret;
+}
+
+int ce_aes_expandkey(struct crypto_aes_ctx *ctx, const u8 *in_key,
+ unsigned int key_len)
+{
+ /*
+ * The AES key schedule round constants
+ */
+ static u8 const rcon[] = {
+ 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36,
+ };
+
+ u32 kwords = key_len / sizeof(u32);
+ struct aes_block *key_enc, *key_dec;
+ int i, j;
+
+ if (key_len != AES_KEYSIZE_128 &&
+ key_len != AES_KEYSIZE_192 &&
+ key_len != AES_KEYSIZE_256)
+ return -EINVAL;
+
+ memcpy(ctx->key_enc, in_key, key_len);
+ ctx->key_length = key_len;
+
+ kernel_neon_begin_partial(2);
+ for (i = 0; i < sizeof(rcon); i++) {
+ u32 *rki = ctx->key_enc + (i * kwords);
+ u32 *rko = rki + kwords;
+
+ rko[0] = ror32(aes_sub(rki[kwords - 1]), 8) ^ rcon[i] ^ rki[0];
+ rko[1] = rko[0] ^ rki[1];
+ rko[2] = rko[1] ^ rki[2];
+ rko[3] = rko[2] ^ rki[3];
+
+ if (key_len == AES_KEYSIZE_192) {
+ if (i >= 7)
+ break;
+ rko[4] = rko[3] ^ rki[4];
+ rko[5] = rko[4] ^ rki[5];
+ } else if (key_len == AES_KEYSIZE_256) {
+ if (i >= 6)
+ break;
+ rko[4] = aes_sub(rko[3]) ^ rki[4];
+ rko[5] = rko[4] ^ rki[5];
+ rko[6] = rko[5] ^ rki[6];
+ rko[7] = rko[6] ^ rki[7];
+ }
+ }
+
+ /*
+ * Generate the decryption keys for the Inverse Equivalent Cipher.
+ * This involves reversing the order of the round keys, and applying
+ * the Inverse Mix Columns transformation on all but the first and
+ * the last one.
+ */
+ key_enc = (struct aes_block *)ctx->key_enc;
+ key_dec = (struct aes_block *)ctx->key_dec;
+ j = num_rounds(ctx);
+
+ key_dec[0] = key_enc[j];
+ for (i = 1, j--; j > 0; i++, j--)
+ __asm__("ld1 {v0.16b}, %[in] ;"
+ "aesimc v1.16b, v0.16b ;"
+ "st1 {v1.16b}, %[out] ;"
+
+ : [out] "=Q"(key_dec[i])
+ : [in] "Q"(key_enc[j])
+ : "v0","v1");
+ key_dec[i] = key_enc[0];
+
+ kernel_neon_end();
+ return 0;
+}
+EXPORT_SYMBOL(ce_aes_expandkey);
+
+int ce_aes_setkey(struct crypto_tfm *tfm, const u8 *in_key,
+ unsigned int key_len)
+{
+ struct crypto_aes_ctx *ctx = crypto_tfm_ctx(tfm);
+ int ret;
+
+ ret = ce_aes_expandkey(ctx, in_key, key_len);
+ if (!ret)
+ return 0;
+
+ tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
+ return -EINVAL;
+}
+EXPORT_SYMBOL(ce_aes_setkey);
+
static struct crypto_alg aes_alg = {
.cra_name = "aes",
.cra_driver_name = "aes-ce",
@@ -135,7 +245,7 @@ static struct crypto_alg aes_alg = {
.cra_cipher = {
.cia_min_keysize = AES_MIN_KEY_SIZE,
.cia_max_keysize = AES_MAX_KEY_SIZE,
- .cia_setkey = crypto_aes_set_key,
+ .cia_setkey = ce_aes_setkey,
.cia_encrypt = aes_cipher_encrypt,
.cia_decrypt = aes_cipher_decrypt
}
diff --git a/arch/arm64/crypto/aes-ce-setkey.h b/arch/arm64/crypto/aes-ce-setkey.h
new file mode 100644
index 000000000000..9d61e98ae347
--- /dev/null
+++ b/arch/arm64/crypto/aes-ce-setkey.h
@@ -0,0 +1,5 @@
+
+int ce_aes_setkey(struct crypto_tfm *tfm, const u8 *in_key,
+ unsigned int key_len);
+int ce_aes_expandkey(struct crypto_aes_ctx *ctx, const u8 *in_key,
+ unsigned int key_len);
diff --git a/arch/arm64/crypto/aes-glue.c b/arch/arm64/crypto/aes-glue.c
index 79cd911ef88c..801aae32841f 100644
--- a/arch/arm64/crypto/aes-glue.c
+++ b/arch/arm64/crypto/aes-glue.c
@@ -16,9 +16,13 @@
#include <linux/module.h>
#include <linux/cpufeature.h>
+#include "aes-ce-setkey.h"
+
#ifdef USE_V8_CRYPTO_EXTENSIONS
#define MODE "ce"
#define PRIO 300
+#define aes_setkey ce_aes_setkey
+#define aes_expandkey ce_aes_expandkey
#define aes_ecb_encrypt ce_aes_ecb_encrypt
#define aes_ecb_decrypt ce_aes_ecb_decrypt
#define aes_cbc_encrypt ce_aes_cbc_encrypt
@@ -30,6 +34,8 @@ MODULE_DESCRIPTION("AES-ECB/CBC/CTR/XTS using ARMv8 Crypto Extensions");
#else
#define MODE "neon"
#define PRIO 200
+#define aes_setkey crypto_aes_set_key
+#define aes_expandkey crypto_aes_expand_key
#define aes_ecb_encrypt neon_aes_ecb_encrypt
#define aes_ecb_decrypt neon_aes_ecb_decrypt
#define aes_cbc_encrypt neon_aes_cbc_encrypt
@@ -79,10 +85,10 @@ static int xts_set_key(struct crypto_tfm *tfm, const u8 *in_key,
struct crypto_aes_xts_ctx *ctx = crypto_tfm_ctx(tfm);
int ret;
- ret = crypto_aes_expand_key(&ctx->key1, in_key, key_len / 2);
+ ret = aes_expandkey(&ctx->key1, in_key, key_len / 2);
if (!ret)
- ret = crypto_aes_expand_key(&ctx->key2, &in_key[key_len / 2],
- key_len / 2);
+ ret = aes_expandkey(&ctx->key2, &in_key[key_len / 2],
+ key_len / 2);
if (!ret)
return 0;
@@ -288,7 +294,7 @@ static struct crypto_alg aes_algs[] = { {
.min_keysize = AES_MIN_KEY_SIZE,
.max_keysize = AES_MAX_KEY_SIZE,
.ivsize = AES_BLOCK_SIZE,
- .setkey = crypto_aes_set_key,
+ .setkey = aes_setkey,
.encrypt = ecb_encrypt,
.decrypt = ecb_decrypt,
},
@@ -306,7 +312,7 @@ static struct crypto_alg aes_algs[] = { {
.min_keysize = AES_MIN_KEY_SIZE,
.max_keysize = AES_MAX_KEY_SIZE,
.ivsize = AES_BLOCK_SIZE,
- .setkey = crypto_aes_set_key,
+ .setkey = aes_setkey,
.encrypt = cbc_encrypt,
.decrypt = cbc_decrypt,
},
@@ -324,7 +330,7 @@ static struct crypto_alg aes_algs[] = { {
.min_keysize = AES_MIN_KEY_SIZE,
.max_keysize = AES_MAX_KEY_SIZE,
.ivsize = AES_BLOCK_SIZE,
- .setkey = crypto_aes_set_key,
+ .setkey = aes_setkey,
.encrypt = ctr_encrypt,
.decrypt = ctr_encrypt,
},
--
1.8.3.2
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