crypto: x86/aes-ni-xts - rewrite and drop indirections via glue helper

The AES-NI driver implements XTS via the glue helper, which consumes
a struct with sets of function pointers which are invoked on chunks
of input data of the appropriate size, as annotated in the struct.

Let's get rid of this indirection, so that we can perform direct calls
to the assembler helpers. Instead, let's adopt the arm64 strategy, i.e.,
provide a helper which can consume inputs of any size, provided that the
penultimate, full block is passed via the last call if ciphertext stealing
needs to be applied.

This also allows us to enable the XTS mode for i386.

Tested-by: Eric Biggers <ebiggers@google.com> # x86_64
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 124 insertions, 96 deletions

diff --git a/arch/x86/crypto/aesni-intel_glue.c b/arch/x86/crypto/aesni-intel_glue.c
index 84e3ed49b35d..2116bc2b9507 100644
--- a/arch/x86/crypto/aesni-intel_glue.c
+++ b/arch/x86/crypto/aesni-intel_glue.c
@@ -33,9 +33,6 @@
 #include <crypto/internal/skcipher.h>
 #include <linux/workqueue.h>
 #include <linux/spinlock.h>
-#ifdef CONFIG_X86_64
-#include <asm/crypto/glue_helper.h>
-#endif
 
 
 #define AESNI_ALIGN	16
@@ -632,98 +629,6 @@ static int ctr_crypt(struct skcipher_request *req)
 	return err;
 }
 
-static int xts_aesni_setkey(struct crypto_skcipher *tfm, const u8 *key,
-			    unsigned int keylen)
-{
-	struct aesni_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
-	int err;
-
-	err = xts_verify_key(tfm, key, keylen);
-	if (err)
-		return err;
-
-	keylen /= 2;
-
-	/* first half of xts-key is for crypt */
-	err = aes_set_key_common(crypto_skcipher_tfm(tfm), ctx->raw_crypt_ctx,
-				 key, keylen);
-	if (err)
-		return err;
-
-	/* second half of xts-key is for tweak */
-	return aes_set_key_common(crypto_skcipher_tfm(tfm), ctx->raw_tweak_ctx,
-				  key + keylen, keylen);
-}
-
-
-static void aesni_xts_enc(const void *ctx, u8 *dst, const u8 *src, le128 *iv)
-{
-	glue_xts_crypt_128bit_one(ctx, dst, src, iv, aesni_enc);
-}
-
-static void aesni_xts_dec(const void *ctx, u8 *dst, const u8 *src, le128 *iv)
-{
-	glue_xts_crypt_128bit_one(ctx, dst, src, iv, aesni_dec);
-}
-
-static void aesni_xts_enc32(const void *ctx, u8 *dst, const u8 *src, le128 *iv)
-{
-	aesni_xts_encrypt(ctx, dst, src, 32 * AES_BLOCK_SIZE, (u8 *)iv);
-}
-
-static void aesni_xts_dec32(const void *ctx, u8 *dst, const u8 *src, le128 *iv)
-{
-	aesni_xts_decrypt(ctx, dst, src, 32 * AES_BLOCK_SIZE, (u8 *)iv);
-}
-
-static const struct common_glue_ctx aesni_enc_xts = {
-	.num_funcs = 2,
-	.fpu_blocks_limit = 1,
-
-	.funcs = { {
-		.num_blocks = 32,
-		.fn_u = { .xts = aesni_xts_enc32 }
-	}, {
-		.num_blocks = 1,
-		.fn_u = { .xts = aesni_xts_enc }
-	} }
-};
-
-static const struct common_glue_ctx aesni_dec_xts = {
-	.num_funcs = 2,
-	.fpu_blocks_limit = 1,
-
-	.funcs = { {
-		.num_blocks = 32,
-		.fn_u = { .xts = aesni_xts_dec32 }
-	}, {
-		.num_blocks = 1,
-		.fn_u = { .xts = aesni_xts_dec }
-	} }
-};
-
-static int xts_encrypt(struct skcipher_request *req)
-{
-	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
-	struct aesni_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
-
-	return glue_xts_req_128bit(&aesni_enc_xts, req, aesni_enc,
-				   aes_ctx(ctx->raw_tweak_ctx),
-				   aes_ctx(ctx->raw_crypt_ctx),
-				   false);
-}
-
-static int xts_decrypt(struct skcipher_request *req)
-{
-	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
-	struct aesni_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
-
-	return glue_xts_req_128bit(&aesni_dec_xts, req, aesni_enc,
-				   aes_ctx(ctx->raw_tweak_ctx),
-				   aes_ctx(ctx->raw_crypt_ctx),
-				   true);
-}
-
 static int
 rfc4106_set_hash_subkey(u8 *hash_subkey, const u8 *key, unsigned int key_len)
 {
@@ -996,6 +901,128 @@ static int helper_rfc4106_decrypt(struct aead_request *req)
 }
 #endif
 
+static int xts_aesni_setkey(struct crypto_skcipher *tfm, const u8 *key,
+			    unsigned int keylen)
+{
+	struct aesni_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
+	int err;
+
+	err = xts_verify_key(tfm, key, keylen);
+	if (err)
+		return err;
+
+	keylen /= 2;
+
+	/* first half of xts-key is for crypt */
+	err = aes_set_key_common(crypto_skcipher_tfm(tfm), ctx->raw_crypt_ctx,
+				 key, keylen);
+	if (err)
+		return err;
+
+	/* second half of xts-key is for tweak */
+	return aes_set_key_common(crypto_skcipher_tfm(tfm), ctx->raw_tweak_ctx,
+				  key + keylen, keylen);
+}
+
+static int xts_crypt(struct skcipher_request *req, bool encrypt)
+{
+	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
+	struct aesni_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
+	int tail = req->cryptlen % AES_BLOCK_SIZE;
+	struct skcipher_request subreq;
+	struct skcipher_walk walk;
+	int err;
+
+	if (req->cryptlen < AES_BLOCK_SIZE)
+		return -EINVAL;
+
+	err = skcipher_walk_virt(&walk, req, false);
+
+	if (unlikely(tail > 0 && walk.nbytes < walk.total)) {
+		int blocks = DIV_ROUND_UP(req->cryptlen, AES_BLOCK_SIZE) - 2;
+
+		skcipher_walk_abort(&walk);
+
+		skcipher_request_set_tfm(&subreq, tfm);
+		skcipher_request_set_callback(&subreq,
+					      skcipher_request_flags(req),
+					      NULL, NULL);
+		skcipher_request_set_crypt(&subreq, req->src, req->dst,
+					   blocks * AES_BLOCK_SIZE, req->iv);
+		req = &subreq;
+		err = skcipher_walk_virt(&walk, req, false);
+	} else {
+		tail = 0;
+	}
+
+	kernel_fpu_begin();
+
+	/* calculate first value of T */
+	aesni_enc(aes_ctx(ctx->raw_tweak_ctx), walk.iv, walk.iv);
+
+	while (walk.nbytes > 0) {
+		int nbytes = walk.nbytes;
+
+		if (nbytes < walk.total)
+			nbytes &= ~(AES_BLOCK_SIZE - 1);
+
+		if (encrypt)
+			aesni_xts_encrypt(aes_ctx(ctx->raw_crypt_ctx),
+					  walk.dst.virt.addr, walk.src.virt.addr,
+					  nbytes, walk.iv);
+		else
+			aesni_xts_decrypt(aes_ctx(ctx->raw_crypt_ctx),
+					  walk.dst.virt.addr, walk.src.virt.addr,
+					  nbytes, walk.iv);
+		kernel_fpu_end();
+
+		err = skcipher_walk_done(&walk, walk.nbytes - nbytes);
+
+		if (walk.nbytes > 0)
+			kernel_fpu_begin();
+	}
+
+	if (unlikely(tail > 0 && !err)) {
+		struct scatterlist sg_src[2], sg_dst[2];
+		struct scatterlist *src, *dst;
+
+		dst = src = scatterwalk_ffwd(sg_src, req->src, req->cryptlen);
+		if (req->dst != req->src)
+			dst = scatterwalk_ffwd(sg_dst, req->dst, req->cryptlen);
+
+		skcipher_request_set_crypt(req, src, dst, AES_BLOCK_SIZE + tail,
+					   req->iv);
+
+		err = skcipher_walk_virt(&walk, &subreq, false);
+		if (err)
+			return err;
+
+		kernel_fpu_begin();
+		if (encrypt)
+			aesni_xts_encrypt(aes_ctx(ctx->raw_crypt_ctx),
+					  walk.dst.virt.addr, walk.src.virt.addr,
+					  walk.nbytes, walk.iv);
+		else
+			aesni_xts_decrypt(aes_ctx(ctx->raw_crypt_ctx),
+					  walk.dst.virt.addr, walk.src.virt.addr,
+					  walk.nbytes, walk.iv);
+		kernel_fpu_end();
+
+		err = skcipher_walk_done(&walk, 0);
+	}
+	return err;
+}
+
+static int xts_encrypt(struct skcipher_request *req)
+{
+	return xts_crypt(req, true);
+}
+
+static int xts_decrypt(struct skcipher_request *req)
+{
+	return xts_crypt(req, false);
+}
+
 static struct crypto_alg aesni_cipher_alg = {
 	.cra_name		= "aes",
 	.cra_driver_name	= "aes-aesni",
@@ -1082,6 +1109,7 @@ static struct skcipher_alg aesni_skciphers[] = {
 		.setkey		= aesni_skcipher_setkey,
 		.encrypt	= ctr_crypt,
 		.decrypt	= ctr_crypt,
+#endif
 	}, {
 		.base = {
 			.cra_name		= "__xts(aes)",
@@ -1095,10 +1123,10 @@ static struct skcipher_alg aesni_skciphers[] = {
 		.min_keysize	= 2 * AES_MIN_KEY_SIZE,
 		.max_keysize	= 2 * AES_MAX_KEY_SIZE,
 		.ivsize		= AES_BLOCK_SIZE,
+		.walksize	= 2 * AES_BLOCK_SIZE,
 		.setkey		= xts_aesni_setkey,
 		.encrypt	= xts_encrypt,
 		.decrypt	= xts_decrypt,
-#endif
 	}
 };