Add an accelerated version of the 'essiv(cbc(aes),aes,sha256'
skcipher, which is used by fscrypt or dm-crypt on systems where
CBC mode is signficantly more performant than XTS mode (e.g., when
using a h/w accelerator which supports the former but not the latter)
This avoids a separate call into the AES cipher for every invocation.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
---
arch/arm64/crypto/aes-glue.c | 123 ++++++++++++++++++++
arch/arm64/crypto/aes-modes.S | 29 ++++-
2 files changed, 151 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/crypto/aes-glue.c b/arch/arm64/crypto/aes-glue.c
index 11b85ce02d7a..7097739e7cd9 100644
--- a/arch/arm64/crypto/aes-glue.c
+++ b/arch/arm64/crypto/aes-glue.c
@@ -12,6 +12,7 @@
#include <asm/hwcap.h>
#include <asm/simd.h>
#include <crypto/aes.h>
+#include <crypto/sha.h>
#include <crypto/internal/hash.h>
#include <crypto/internal/simd.h>
#include <crypto/internal/skcipher.h>
@@ -34,6 +35,8 @@
#define aes_cbc_decrypt ce_aes_cbc_decrypt
#define aes_cbc_cts_encrypt ce_aes_cbc_cts_encrypt
#define aes_cbc_cts_decrypt ce_aes_cbc_cts_decrypt
+#define aes_essiv_cbc_encrypt ce_aes_essiv_cbc_encrypt
+#define aes_essiv_cbc_decrypt ce_aes_essiv_cbc_decrypt
#define aes_ctr_encrypt ce_aes_ctr_encrypt
#define aes_xts_encrypt ce_aes_xts_encrypt
#define aes_xts_decrypt ce_aes_xts_decrypt
@@ -50,6 +53,8 @@ MODULE_DESCRIPTION("AES-ECB/CBC/CTR/XTS using ARMv8 Crypto Extensions");
#define aes_cbc_decrypt neon_aes_cbc_decrypt
#define aes_cbc_cts_encrypt neon_aes_cbc_cts_encrypt
#define aes_cbc_cts_decrypt neon_aes_cbc_cts_decrypt
+#define aes_essiv_cbc_encrypt neon_aes_essiv_cbc_encrypt
+#define aes_essiv_cbc_decrypt neon_aes_essiv_cbc_decrypt
#define aes_ctr_encrypt neon_aes_ctr_encrypt
#define aes_xts_encrypt neon_aes_xts_encrypt
#define aes_xts_decrypt neon_aes_xts_decrypt
@@ -93,6 +98,13 @@ asmlinkage void aes_xts_decrypt(u8 out[], u8 const in[], u32 const rk1[],
int rounds, int blocks, u32 const rk2[], u8 iv[],
int first);
+asmlinkage void aes_essiv_cbc_encrypt(u8 out[], u8 const in[], u32 const rk1[],
+ int rounds, int blocks, u8 iv[],
+ u32 const rk2[]);
+asmlinkage void aes_essiv_cbc_decrypt(u8 out[], u8 const in[], u32 const rk1[],
+ int rounds, int blocks, u8 iv[],
+ u32 const rk2[]);
+
asmlinkage void aes_mac_update(u8 const in[], u32 const rk[], int rounds,
int blocks, u8 dg[], int enc_before,
int enc_after);
@@ -108,6 +120,12 @@ struct crypto_aes_xts_ctx {
struct crypto_aes_ctx __aligned(8) key2;
};
+struct crypto_aes_essiv_cbc_ctx {
+ struct crypto_aes_ctx key1;
+ struct crypto_aes_ctx __aligned(8) key2;
+ struct crypto_shash *hash;
+};
+
struct mac_tfm_ctx {
struct crypto_aes_ctx key;
u8 __aligned(8) consts[];
@@ -145,6 +163,31 @@ static int xts_set_key(struct crypto_skcipher *tfm, const u8 *in_key,
return -EINVAL;
}
+static int essiv_cbc_set_key(struct crypto_skcipher *tfm, const u8 *in_key,
+ unsigned int key_len)
+{
+ struct crypto_aes_essiv_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
+ SHASH_DESC_ON_STACK(desc, ctx->hash);
+ u8 digest[SHA256_DIGEST_SIZE];
+ int ret;
+
+ ret = aes_expandkey(&ctx->key1, in_key, key_len);
+ if (ret)
+ goto out;
+
+ desc->tfm = ctx->hash;
+ crypto_shash_digest(desc, in_key, key_len, digest);
+
+ ret = aes_expandkey(&ctx->key2, digest, sizeof(digest));
+ if (ret)
+ goto out;
+
+ return 0;
+out:
+ crypto_skcipher_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
+ return -EINVAL;
+}
+
static int ecb_encrypt(struct skcipher_request *req)
{
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
@@ -359,6 +402,68 @@ static int cts_cbc_decrypt(struct skcipher_request *req)
return skcipher_walk_done(&walk, 0);
}
+static int essiv_cbc_init_tfm(struct crypto_skcipher *tfm)
+{
+ struct crypto_aes_essiv_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
+
+ ctx->hash = crypto_alloc_shash("sha256", 0, 0);
+ if (IS_ERR(ctx->hash))
+ return PTR_ERR(ctx->hash);
+
+ return 0;
+}
+
+static void essiv_cbc_exit_tfm(struct crypto_skcipher *tfm)
+{
+ struct crypto_aes_essiv_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
+
+ crypto_free_shash(ctx->hash);
+}
+
+static int essiv_cbc_encrypt(struct skcipher_request *req)
+{
+ struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
+ struct crypto_aes_essiv_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
+ int err, rounds = 6 + ctx->key1.key_length / 4;
+ struct skcipher_walk walk;
+ unsigned int blocks;
+
+ err = skcipher_walk_virt(&walk, req, false);
+
+ blocks = walk.nbytes / AES_BLOCK_SIZE;
+ if (blocks) {
+ kernel_neon_begin();
+ aes_essiv_cbc_encrypt(walk.dst.virt.addr, walk.src.virt.addr,
+ ctx->key1.key_enc, rounds, blocks,
+ req->iv, ctx->key2.key_enc);
+ kernel_neon_end();
+ err = skcipher_walk_done(&walk, walk.nbytes % AES_BLOCK_SIZE);
+ }
+ return err ?: cbc_encrypt_walk(req, &walk);
+}
+
+static int essiv_cbc_decrypt(struct skcipher_request *req)
+{
+ struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
+ struct crypto_aes_essiv_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
+ int err, rounds = 6 + ctx->key1.key_length / 4;
+ struct skcipher_walk walk;
+ unsigned int blocks;
+
+ err = skcipher_walk_virt(&walk, req, false);
+
+ blocks = walk.nbytes / AES_BLOCK_SIZE;
+ if (blocks) {
+ kernel_neon_begin();
+ aes_essiv_cbc_decrypt(walk.dst.virt.addr, walk.src.virt.addr,
+ ctx->key1.key_dec, rounds, blocks,
+ req->iv, ctx->key2.key_enc);
+ kernel_neon_end();
+ err = skcipher_walk_done(&walk, walk.nbytes % AES_BLOCK_SIZE);
+ }
+ return err ?: cbc_decrypt_walk(req, &walk);
+}
+
static int ctr_encrypt(struct skcipher_request *req)
{
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
@@ -502,6 +607,24 @@ static struct skcipher_alg aes_algs[] = { {
.encrypt = cts_cbc_encrypt,
.decrypt = cts_cbc_decrypt,
.init = cts_cbc_init_tfm,
+}, {
+ .base = {
+ .cra_name = "__essiv(cbc(aes),aes,sha256)",
+ .cra_driver_name = "__essiv-cbc-aes-sha256-" MODE,
+ .cra_priority = PRIO + 1,
+ .cra_flags = CRYPTO_ALG_INTERNAL,
+ .cra_blocksize = AES_BLOCK_SIZE,
+ .cra_ctxsize = sizeof(struct crypto_aes_essiv_cbc_ctx),
+ .cra_module = THIS_MODULE,
+ },
+ .min_keysize = AES_MIN_KEY_SIZE,
+ .max_keysize = AES_MAX_KEY_SIZE,
+ .ivsize = AES_BLOCK_SIZE,
+ .setkey = essiv_cbc_set_key,
+ .encrypt = essiv_cbc_encrypt,
+ .decrypt = essiv_cbc_decrypt,
+ .init = essiv_cbc_init_tfm,
+ .exit = essiv_cbc_exit_tfm,
}, {
.base = {
.cra_name = "__ctr(aes)",
diff --git a/arch/arm64/crypto/aes-modes.S b/arch/arm64/crypto/aes-modes.S
index 4c7ce231963c..2ef3d7244ea8 100644
--- a/arch/arm64/crypto/aes-modes.S
+++ b/arch/arm64/crypto/aes-modes.S
@@ -91,10 +91,25 @@ AES_ENDPROC(aes_ecb_decrypt)
* int blocks, u8 iv[])
* aes_cbc_decrypt(u8 out[], u8 const in[], u8 const rk[], int rounds,
* int blocks, u8 iv[])
+ * aes_essiv_cbc_encrypt(u8 out[], u8 const in[], u32 const rk1[],
+ * int rounds, int blocks, u8 iv[],
+ * u32 const rk2[]);
+ * aes_essiv_cbc_decrypt(u8 out[], u8 const in[], u32 const rk1[],
+ * int rounds, int blocks, u8 iv[],
+ * u32 const rk2[]);
*/
+AES_ENTRY(aes_essiv_cbc_encrypt)
+ ld1 {v4.16b}, [x5] /* get iv */
+
+ mov w8, #14 /* AES-256: 14 rounds */
+ enc_prepare w8, x6, x7
+ encrypt_block v4, w8, x6, x7, w9
+ b .Lessivcbcencstart
+
AES_ENTRY(aes_cbc_encrypt)
ld1 {v4.16b}, [x5] /* get iv */
+.Lessivcbcencstart:
enc_prepare w3, x2, x6
.Lcbcencloop4x:
@@ -126,13 +141,25 @@ AES_ENTRY(aes_cbc_encrypt)
st1 {v4.16b}, [x5] /* return iv */
ret
AES_ENDPROC(aes_cbc_encrypt)
+AES_ENDPROC(aes_essiv_cbc_encrypt)
+AES_ENTRY(aes_essiv_cbc_decrypt)
+ stp x29, x30, [sp, #-16]!
+ mov x29, sp
+
+ ld1 {v7.16b}, [x5] /* get iv */
+
+ mov w8, #14 /* AES-256: 14 rounds */
+ enc_prepare w8, x6, x7
+ encrypt_block v7, w8, x6, x7, w9
+ b .Lessivcbcdecstart
AES_ENTRY(aes_cbc_decrypt)
stp x29, x30, [sp, #-16]!
mov x29, sp
ld1 {v7.16b}, [x5] /* get iv */
+.Lessivcbcdecstart:
dec_prepare w3, x2, x6
.LcbcdecloopNx:
@@ -168,6 +195,7 @@ AES_ENTRY(aes_cbc_decrypt)
ldp x29, x30, [sp], #16
ret
AES_ENDPROC(aes_cbc_decrypt)
+AES_ENDPROC(aes_essiv_cbc_decrypt)
/*
@@ -247,7 +275,6 @@ AES_ENDPROC(aes_cbc_cts_decrypt)
.byte 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff
.previous
-
/*
* aes_ctr_encrypt(u8 out[], u8 const in[], u8 const rk[], int rounds,
* int blocks, u8 ctr[])
--
2.17.1
