crypto: arm/aes - replace bit-sliced OpenSSL NEON code

This replaces the unwieldy generated implementation of bit-sliced AES
in CBC/CTR/XTS modes that originated in the OpenSSL project with a
new version that is heavily based on the OpenSSL implementation, but
has a number of advantages over the old version:
- it does not rely on the scalar AES cipher that also originated in the
  OpenSSL project and contains redundant lookup tables and key schedule
  generation routines (which we already have in crypto/aes_generic.)
- it uses the same expanded key schedule for encryption and decryption,
  reducing the size of the per-key data structure by 1696 bytes
- it adds an implementation of AES in ECB mode, which can be wrapped by
  other generic chaining mode implementations
- it moves the handling of corner cases that are non critical to performance
  to the glue layer written in C
- it was written directly in assembler rather than generated from a Perl
  script
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

arch/arm/crypto/Kconfig

@@ -73,6 +73,7 @@ config CRYPTO_AES_ARM_BS
 	depends on KERNEL_MODE_NEON
 	select CRYPTO_BLKCIPHER
 	select CRYPTO_SIMD
+	select CRYPTO_AES_ARM
 	help
 	  Use a faster and more secure NEON based implementation of AES in CBC,
 	  CTR and XTS modes

arch/arm/crypto/Makefile

@@ -28,7 +28,7 @@ endif
 endif
 
 aes-arm-y	:= aes-cipher-core.o aes-cipher-glue.o
-aes-arm-bs-y	:= aes-armv4.o aesbs-core.o aesbs-glue.o
+aes-arm-bs-y	:= aes-neonbs-core.o aes-neonbs-glue.o
 sha1-arm-y	:= sha1-armv4-large.o sha1_glue.o
 sha1-arm-neon-y	:= sha1-armv7-neon.o sha1_neon_glue.o
 sha256-arm-neon-$(CONFIG_KERNEL_MODE_NEON) := sha256_neon_glue.o
@@ -46,13 +46,10 @@ chacha20-neon-y := chacha20-neon-core.o chacha20-neon-glue.o
 quiet_cmd_perl = PERL    $@
       cmd_perl = $(PERL) $(<) > $(@)
 
-$(src)/aesbs-core.S_shipped: $(src)/bsaes-armv7.pl
-	$(call cmd,perl)
-
 $(src)/sha256-core.S_shipped: $(src)/sha256-armv4.pl
 	$(call cmd,perl)
 
 $(src)/sha512-core.S_shipped: $(src)/sha512-armv4.pl
 	$(call cmd,perl)
 
-.PRECIOUS: $(obj)/aesbs-core.S $(obj)/sha256-core.S $(obj)/sha512-core.S
+.PRECIOUS: $(obj)/sha256-core.S $(obj)/sha512-core.S

arch/arm/crypto/aes_glue.h

-
-#define AES_MAXNR 14
-
-struct AES_KEY {
-	unsigned int rd_key[4 * (AES_MAXNR + 1)];
-	int rounds;
-};
-
-struct AES_CTX {
-	struct AES_KEY enc_key;
-	struct AES_KEY dec_key;
-};
-
-asmlinkage void AES_encrypt(const u8 *in, u8 *out, struct AES_KEY *ctx);
-asmlinkage void AES_decrypt(const u8 *in, u8 *out, struct AES_KEY *ctx);
-asmlinkage int private_AES_set_decrypt_key(const unsigned char *userKey,
-					   const int bits, struct AES_KEY *key);
-asmlinkage int private_AES_set_encrypt_key(const unsigned char *userKey,
-					   const int bits, struct AES_KEY *key);

arch/arm/crypto/aesbs-glue.c

-/*
- * linux/arch/arm/crypto/aesbs-glue.c - glue code for NEON bit sliced AES
- *
- * Copyright (C) 2013 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
- * published by the Free Software Foundation.
- */
-
-#include <asm/neon.h>
-#include <crypto/aes.h>
-#include <crypto/cbc.h>
-#include <crypto/internal/simd.h>
-#include <crypto/internal/skcipher.h>
-#include <linux/module.h>
-#include <crypto/xts.h>
-
-#include "aes_glue.h"
-
-#define BIT_SLICED_KEY_MAXSIZE	(128 * (AES_MAXNR - 1) + 2 * AES_BLOCK_SIZE)
-
-struct BS_KEY {
-	struct AES_KEY	rk;
-	int		converted;
-	u8 __aligned(8)	bs[BIT_SLICED_KEY_MAXSIZE];
-} __aligned(8);
-
-asmlinkage void bsaes_enc_key_convert(u8 out[], struct AES_KEY const *in);
-asmlinkage void bsaes_dec_key_convert(u8 out[], struct AES_KEY const *in);
-
-asmlinkage void bsaes_cbc_encrypt(u8 const in[], u8 out[], u32 bytes,
-				  struct BS_KEY *key, u8 iv[]);
-
-asmlinkage void bsaes_ctr32_encrypt_blocks(u8 const in[], u8 out[], u32 blocks,
-					   struct BS_KEY *key, u8 const iv[]);
-
-asmlinkage void bsaes_xts_encrypt(u8 const in[], u8 out[], u32 bytes,
-				  struct BS_KEY *key, u8 tweak[]);
-
-asmlinkage void bsaes_xts_decrypt(u8 const in[], u8 out[], u32 bytes,
-				  struct BS_KEY *key, u8 tweak[]);
-
-struct aesbs_cbc_ctx {
-	struct AES_KEY	enc;
-	struct BS_KEY	dec;
-};
-
-struct aesbs_ctr_ctx {
-	struct BS_KEY	enc;
-};
-
-struct aesbs_xts_ctx {
-	struct BS_KEY	enc;
-	struct BS_KEY	dec;
-	struct AES_KEY	twkey;
-};
-
-static int aesbs_cbc_set_key(struct crypto_skcipher *tfm, const u8 *in_key,
-			     unsigned int key_len)
-{
-	struct aesbs_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
-	int bits = key_len * 8;
-
-	if (private_AES_set_encrypt_key(in_key, bits, &ctx->enc)) {
-		crypto_skcipher_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
-		return -EINVAL;
-	}
-	ctx->dec.rk = ctx->enc;
-	private_AES_set_decrypt_key(in_key, bits, &ctx->dec.rk);
-	ctx->dec.converted = 0;
-	return 0;
-}
-
-static int aesbs_ctr_set_key(struct crypto_skcipher *tfm, const u8 *in_key,
-			     unsigned int key_len)
-{
-	struct aesbs_ctr_ctx *ctx = crypto_skcipher_ctx(tfm);
-	int bits = key_len * 8;
-
-	if (private_AES_set_encrypt_key(in_key, bits, &ctx->enc.rk)) {
-		crypto_skcipher_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
-		return -EINVAL;
-	}
-	ctx->enc.converted = 0;
-	return 0;
-}
-
-static int aesbs_xts_set_key(struct crypto_skcipher *tfm, const u8 *in_key,
-			     unsigned int key_len)
-{
-	struct aesbs_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
-	int bits = key_len * 4;
-	int err;
-
-	err = xts_verify_key(tfm, in_key, key_len);
-	if (err)
-		return err;
-
-	if (private_AES_set_encrypt_key(in_key, bits, &ctx->enc.rk)) {
-		crypto_skcipher_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
-		return -EINVAL;
-	}
-	ctx->dec.rk = ctx->enc.rk;
-	private_AES_set_decrypt_key(in_key, bits, &ctx->dec.rk);
-	private_AES_set_encrypt_key(in_key + key_len / 2, bits, &ctx->twkey);
-	ctx->enc.converted = ctx->dec.converted = 0;
-	return 0;
-}
-
-static inline void aesbs_encrypt_one(struct crypto_skcipher *tfm,
-				     const u8 *src, u8 *dst)
-{
-	struct aesbs_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
-
-	AES_encrypt(src, dst, &ctx->enc);
-}
-
-static int aesbs_cbc_encrypt(struct skcipher_request *req)
-{
-	return crypto_cbc_encrypt_walk(req, aesbs_encrypt_one);
-}
-
-static inline void aesbs_decrypt_one(struct crypto_skcipher *tfm,
-				     const u8 *src, u8 *dst)
-{
-	struct aesbs_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
-
-	AES_decrypt(src, dst, &ctx->dec.rk);
-}
-
-static int aesbs_cbc_decrypt(struct skcipher_request *req)
-{
-	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
-	struct aesbs_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
-	struct skcipher_walk walk;
-	unsigned int nbytes;
-	int err;
-
-	for (err = skcipher_walk_virt(&walk, req, false);
-	     (nbytes = walk.nbytes); err = skcipher_walk_done(&walk, nbytes)) {
-		u32 blocks = nbytes / AES_BLOCK_SIZE;
-		u8 *dst = walk.dst.virt.addr;
-		u8 *src = walk.src.virt.addr;
-		u8 *iv = walk.iv;
-
-		if (blocks >= 8) {
-			kernel_neon_begin();
-			bsaes_cbc_encrypt(src, dst, nbytes, &ctx->dec, iv);
-			kernel_neon_end();
-			nbytes %= AES_BLOCK_SIZE;
-			continue;
-		}
-
-		nbytes = crypto_cbc_decrypt_blocks(&walk, tfm,
-						   aesbs_decrypt_one);
-	}
-	return err;
-}
-
-static void inc_be128_ctr(__be32 ctr[], u32 addend)
-{
-	int i;
-
-	for (i = 3; i >= 0; i--, addend = 1) {
-		u32 n = be32_to_cpu(ctr[i]) + addend;
-
-		ctr[i] = cpu_to_be32(n);
-		if (n >= addend)
-			break;
-	}
-}
-
-static int aesbs_ctr_encrypt(struct skcipher_request *req)
-{
-	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
-	struct aesbs_ctr_ctx *ctx = crypto_skcipher_ctx(tfm);
-	struct skcipher_walk walk;
-	u32 blocks;
-	int err;
-
-	err = skcipher_walk_virt(&walk, req, false);
-
-	while ((blocks = walk.nbytes / AES_BLOCK_SIZE)) {
-		u32 tail = walk.nbytes % AES_BLOCK_SIZE;
-		__be32 *ctr = (__be32 *)walk.iv;
-		u32 headroom = UINT_MAX - be32_to_cpu(ctr[3]);
-
-		/* avoid 32 bit counter overflow in the NEON code */
-		if (unlikely(headroom < blocks)) {
-			blocks = headroom + 1;
-			tail = walk.nbytes - blocks * AES_BLOCK_SIZE;
-		}
-		kernel_neon_begin();
-		bsaes_ctr32_encrypt_blocks(walk.src.virt.addr,
-					   walk.dst.virt.addr, blocks,
-					   &ctx->enc, walk.iv);
-		kernel_neon_end();
-		inc_be128_ctr(ctr, blocks);
-
-		err = skcipher_walk_done(&walk, tail);
-	}
-	if (walk.nbytes) {
-		u8 *tdst = walk.dst.virt.addr + blocks * AES_BLOCK_SIZE;
-		u8 *tsrc = walk.src.virt.addr + blocks * AES_BLOCK_SIZE;
-		u8 ks[AES_BLOCK_SIZE];
-
-		AES_encrypt(walk.iv, ks, &ctx->enc.rk);
-		if (tdst != tsrc)
-			memcpy(tdst, tsrc, walk.nbytes);
-		crypto_xor(tdst, ks, walk.nbytes);
-		err = skcipher_walk_done(&walk, 0);
-	}
-	return err;
-}
-
-static int aesbs_xts_encrypt(struct skcipher_request *req)
-{
-	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
-	struct aesbs_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
-	struct skcipher_walk walk;
-	int err;
-
-	err = skcipher_walk_virt(&walk, req, false);
-
-	/* generate the initial tweak */
-	AES_encrypt(walk.iv, walk.iv, &ctx->twkey);
-
-	while (walk.nbytes) {
-		kernel_neon_begin();
-		bsaes_xts_encrypt(walk.src.virt.addr, walk.dst.virt.addr,
-				  walk.nbytes, &ctx->enc, walk.iv);
-		kernel_neon_end();
-		err = skcipher_walk_done(&walk, walk.nbytes % AES_BLOCK_SIZE);
-	}
-	return err;
-}
-
-static int aesbs_xts_decrypt(struct skcipher_request *req)
-{
-	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
-	struct aesbs_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
-	struct skcipher_walk walk;
-	int err;
-
-	err = skcipher_walk_virt(&walk, req, false);
-
-	/* generate the initial tweak */
-	AES_encrypt(walk.iv, walk.iv, &ctx->twkey);
-
-	while (walk.nbytes) {
-		kernel_neon_begin();
-		bsaes_xts_decrypt(walk.src.virt.addr, walk.dst.virt.addr,
-				  walk.nbytes, &ctx->dec, walk.iv);
-		kernel_neon_end();
-		err = skcipher_walk_done(&walk, walk.nbytes % AES_BLOCK_SIZE);
-	}
-	return err;
-}
-
-static struct skcipher_alg aesbs_algs[] = { {
-	.base = {
-		.cra_name		= "__cbc(aes)",
-		.cra_driver_name	= "__cbc-aes-neonbs",
-		.cra_priority		= 300,
-		.cra_flags		= CRYPTO_ALG_INTERNAL,
-		.cra_blocksize		= AES_BLOCK_SIZE,
-		.cra_ctxsize		= sizeof(struct aesbs_cbc_ctx),
-		.cra_alignmask		= 7,
-		.cra_module		= THIS_MODULE,
-	},
-	.min_keysize	= AES_MIN_KEY_SIZE,
-	.max_keysize	= AES_MAX_KEY_SIZE,
-	.ivsize		= AES_BLOCK_SIZE,
-	.setkey		= aesbs_cbc_set_key,
-	.encrypt	= aesbs_cbc_encrypt,
-	.decrypt	= aesbs_cbc_decrypt,
-}, {
-	.base = {
-		.cra_name		= "__ctr(aes)",
-		.cra_driver_name	= "__ctr-aes-neonbs",
-		.cra_priority		= 300,
-		.cra_flags		= CRYPTO_ALG_INTERNAL,
-		.cra_blocksize		= 1,
-		.cra_ctxsize		= sizeof(struct aesbs_ctr_ctx),
-		.cra_alignmask		= 7,
-		.cra_module		= THIS_MODULE,
-	},
-	.min_keysize	= AES_MIN_KEY_SIZE,
-	.max_keysize	= AES_MAX_KEY_SIZE,
-	.ivsize		= AES_BLOCK_SIZE,
-	.chunksize	= AES_BLOCK_SIZE,
-	.setkey		= aesbs_ctr_set_key,
-	.encrypt	= aesbs_ctr_encrypt,
-	.decrypt	= aesbs_ctr_encrypt,
-}, {
-	.base = {
-		.cra_name		= "__xts(aes)",
-		.cra_driver_name	= "__xts-aes-neonbs",
-		.cra_priority		= 300,
-		.cra_flags		= CRYPTO_ALG_INTERNAL,
-		.cra_blocksize		= AES_BLOCK_SIZE,
-		.cra_ctxsize		= sizeof(struct aesbs_xts_ctx),
-		.cra_alignmask		= 7,
-		.cra_module		= THIS_MODULE,
-	},
-	.min_keysize	= 2 * AES_MIN_KEY_SIZE,
-	.max_keysize	= 2 * AES_MAX_KEY_SIZE,
-	.ivsize		= AES_BLOCK_SIZE,
-	.setkey		= aesbs_xts_set_key,
-	.encrypt	= aesbs_xts_encrypt,
-	.decrypt	= aesbs_xts_decrypt,
-} };
-
-struct simd_skcipher_alg *aesbs_simd_algs[ARRAY_SIZE(aesbs_algs)];
-
-static void aesbs_mod_exit(void)
-{
-	int i;
-
-	for (i = 0; i < ARRAY_SIZE(aesbs_simd_algs) && aesbs_simd_algs[i]; i++)
-		simd_skcipher_free(aesbs_simd_algs[i]);
-
-	crypto_unregister_skciphers(aesbs_algs, ARRAY_SIZE(aesbs_algs));
-}
-
-static int __init aesbs_mod_init(void)
-{
-	struct simd_skcipher_alg *simd;
-	const char *basename;
-	const char *algname;
-	const char *drvname;
-	int err;
-	int i;
-
-	if (!cpu_has_neon())
-		return -ENODEV;
-
-	err = crypto_register_skciphers(aesbs_algs, ARRAY_SIZE(aesbs_algs));
-	if (err)
-		return err;
-
-	for (i = 0; i < ARRAY_SIZE(aesbs_algs); i++) {
-		algname = aesbs_algs[i].base.cra_name + 2;
-		drvname = aesbs_algs[i].base.cra_driver_name + 2;
-		basename = aesbs_algs[i].base.cra_driver_name;
-		simd = simd_skcipher_create_compat(algname, drvname, basename);
-		err = PTR_ERR(simd);
-		if (IS_ERR(simd))
-			goto unregister_simds;
-
-		aesbs_simd_algs[i] = simd;
-	}
-
-	return 0;
-
-unregister_simds:
-	aesbs_mod_exit();
-	return err;
-}
-
-module_init(aesbs_mod_init);
-module_exit(aesbs_mod_exit);
-
-MODULE_DESCRIPTION("Bit sliced AES in CBC/CTR/XTS modes using NEON");
-MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
-MODULE_LICENSE("GPL");