Commit d0b9007a authored by Herbert Xu's avatar Herbert Xu
Browse files

[CRYPTO] pcbc: Use crypto_xor 



This patch replaces the custom xor in CBC with the generic crypto_xor.

It changes the operations for in-place encryption slightly to avoid
calling crypto_xor with tmpbuf since it is not necessarily aligned.

Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent 50b6544e

crypto/pcbc.c

+24 −81
Original line number Diff line number Diff line
@@ -24,7 +24,6 @@ 


struct crypto_pcbc_ctx {

	struct crypto_cipher *child;

	void (*xor)(u8 *dst, const u8 *src, unsigned int bs);

};



static int crypto_pcbc_setkey(struct crypto_tfm *parent, const u8 *key,
@@ -45,9 +44,7 @@ static int crypto_pcbc_setkey(struct crypto_tfm *parent, const u8 *key, 


static int crypto_pcbc_encrypt_segment(struct blkcipher_desc *desc,

				       struct blkcipher_walk *walk,

				       struct crypto_cipher *tfm,

				       void (*xor)(u8 *, const u8 *,

						   unsigned int))

				       struct crypto_cipher *tfm)

{

	void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =

		crypto_cipher_alg(tfm)->cia_encrypt;
@@ -58,10 +55,10 @@ static int crypto_pcbc_encrypt_segment(struct blkcipher_desc *desc, 
	u8 *iv = walk->iv;



	do {

		xor(iv, src, bsize);

		crypto_xor(iv, src, bsize);

		fn(crypto_cipher_tfm(tfm), dst, iv);

		memcpy(iv, dst, bsize);

		xor(iv, src, bsize);

		crypto_xor(iv, src, bsize);



		src += bsize;

		dst += bsize;
@@ -72,9 +69,7 @@ static int crypto_pcbc_encrypt_segment(struct blkcipher_desc *desc, 


static int crypto_pcbc_encrypt_inplace(struct blkcipher_desc *desc,

				       struct blkcipher_walk *walk,

				       struct crypto_cipher *tfm,

				       void (*xor)(u8 *, const u8 *,

						   unsigned int))

				       struct crypto_cipher *tfm)

{

	void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =

		crypto_cipher_alg(tfm)->cia_encrypt;
@@ -86,10 +81,10 @@ static int crypto_pcbc_encrypt_inplace(struct blkcipher_desc *desc, 


	do {

		memcpy(tmpbuf, src, bsize);

		xor(iv, tmpbuf, bsize);

		crypto_xor(iv, src, bsize);

		fn(crypto_cipher_tfm(tfm), src, iv);

		memcpy(iv, src, bsize);

		xor(iv, tmpbuf, bsize);

		memcpy(iv, tmpbuf, bsize);

		crypto_xor(iv, src, bsize);



		src += bsize;

	} while ((nbytes -= bsize) >= bsize);
@@ -107,7 +102,6 @@ static int crypto_pcbc_encrypt(struct blkcipher_desc *desc, 
	struct crypto_blkcipher *tfm = desc->tfm;

	struct crypto_pcbc_ctx *ctx = crypto_blkcipher_ctx(tfm);

	struct crypto_cipher *child = ctx->child;

	void (*xor)(u8 *, const u8 *, unsigned int bs) = ctx->xor;

	int err;



	blkcipher_walk_init(&walk, dst, src, nbytes);
@@ -115,11 +109,11 @@ static int crypto_pcbc_encrypt(struct blkcipher_desc *desc, 


	while ((nbytes = walk.nbytes)) {

		if (walk.src.virt.addr == walk.dst.virt.addr)

			nbytes = crypto_pcbc_encrypt_inplace(desc, &walk, child,

							     xor);

			nbytes = crypto_pcbc_encrypt_inplace(desc, &walk,

							     child);

		else

			nbytes = crypto_pcbc_encrypt_segment(desc, &walk, child,

							     xor);

			nbytes = crypto_pcbc_encrypt_segment(desc, &walk,

							     child);

		err = blkcipher_walk_done(desc, &walk, nbytes);

	}
@@ -128,9 +122,7 @@ static int crypto_pcbc_encrypt(struct blkcipher_desc *desc, 


static int crypto_pcbc_decrypt_segment(struct blkcipher_desc *desc,

				       struct blkcipher_walk *walk,

				       struct crypto_cipher *tfm,

				       void (*xor)(u8 *, const u8 *,

						   unsigned int))

				       struct crypto_cipher *tfm)

{

	void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =

		crypto_cipher_alg(tfm)->cia_decrypt;
@@ -142,9 +134,9 @@ static int crypto_pcbc_decrypt_segment(struct blkcipher_desc *desc, 


	do {

		fn(crypto_cipher_tfm(tfm), dst, src);

		xor(dst, iv, bsize);

		crypto_xor(dst, iv, bsize);

		memcpy(iv, src, bsize);

		xor(iv, dst, bsize);

		crypto_xor(iv, dst, bsize);



		src += bsize;

		dst += bsize;
@@ -157,9 +149,7 @@ static int crypto_pcbc_decrypt_segment(struct blkcipher_desc *desc, 


static int crypto_pcbc_decrypt_inplace(struct blkcipher_desc *desc,

				       struct blkcipher_walk *walk,

				       struct crypto_cipher *tfm,

				       void (*xor)(u8 *, const u8 *,

						   unsigned int))

				       struct crypto_cipher *tfm)

{

	void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =

		crypto_cipher_alg(tfm)->cia_decrypt;
@@ -172,9 +162,9 @@ static int crypto_pcbc_decrypt_inplace(struct blkcipher_desc *desc, 
	do {

		memcpy(tmpbuf, src, bsize);

		fn(crypto_cipher_tfm(tfm), src, src);

		xor(src, iv, bsize);

		crypto_xor(src, iv, bsize);

		memcpy(iv, tmpbuf, bsize);

		xor(iv, src, bsize);

		crypto_xor(iv, src, bsize);



		src += bsize;

	} while ((nbytes -= bsize) >= bsize);
@@ -192,7 +182,6 @@ static int crypto_pcbc_decrypt(struct blkcipher_desc *desc, 
	struct crypto_blkcipher *tfm = desc->tfm;

	struct crypto_pcbc_ctx *ctx = crypto_blkcipher_ctx(tfm);

	struct crypto_cipher *child = ctx->child;

	void (*xor)(u8 *, const u8 *, unsigned int bs) = ctx->xor;

	int err;



	blkcipher_walk_init(&walk, dst, src, nbytes);
@@ -200,48 +189,17 @@ static int crypto_pcbc_decrypt(struct blkcipher_desc *desc, 


	while ((nbytes = walk.nbytes)) {

		if (walk.src.virt.addr == walk.dst.virt.addr)

			nbytes = crypto_pcbc_decrypt_inplace(desc, &walk, child,

							     xor);

			nbytes = crypto_pcbc_decrypt_inplace(desc, &walk,

							     child);

		else

			nbytes = crypto_pcbc_decrypt_segment(desc, &walk, child,

							     xor);

			nbytes = crypto_pcbc_decrypt_segment(desc, &walk,

							     child);

		err = blkcipher_walk_done(desc, &walk, nbytes);

	}



	return err;

}



static void xor_byte(u8 *a, const u8 *b, unsigned int bs)

{

	do {

		*a++ ^= *b++;

	} while (--bs);

}



static void xor_quad(u8 *dst, const u8 *src, unsigned int bs)

{

	u32 *a = (u32 *)dst;

	u32 *b = (u32 *)src;



	do {

		*a++ ^= *b++;

	} while ((bs -= 4));

}



static void xor_64(u8 *a, const u8 *b, unsigned int bs)

{

	((u32 *)a)[0] ^= ((u32 *)b)[0];

	((u32 *)a)[1] ^= ((u32 *)b)[1];

}



static void xor_128(u8 *a, const u8 *b, unsigned int bs)

{

	((u32 *)a)[0] ^= ((u32 *)b)[0];

	((u32 *)a)[1] ^= ((u32 *)b)[1];

	((u32 *)a)[2] ^= ((u32 *)b)[2];

	((u32 *)a)[3] ^= ((u32 *)b)[3];

}



static int crypto_pcbc_init_tfm(struct crypto_tfm *tfm)

{

	struct crypto_instance *inst = (void *)tfm->__crt_alg;
@@ -249,22 +207,6 @@ static int crypto_pcbc_init_tfm(struct crypto_tfm *tfm) 
	struct crypto_pcbc_ctx *ctx = crypto_tfm_ctx(tfm);

	struct crypto_cipher *cipher;



	switch (crypto_tfm_alg_blocksize(tfm)) {

	case 8:

		ctx->xor = xor_64;

		break;



	case 16:

		ctx->xor = xor_128;

		break;



	default:

		if (crypto_tfm_alg_blocksize(tfm) % 4)

			ctx->xor = xor_byte;

		else

			ctx->xor = xor_quad;

	}



	cipher = crypto_spawn_cipher(spawn);

	if (IS_ERR(cipher))

		return PTR_ERR(cipher);
@@ -304,8 +246,9 @@ static struct crypto_instance *crypto_pcbc_alloc(struct rtattr **tb) 
	inst->alg.cra_alignmask = alg->cra_alignmask;

	inst->alg.cra_type = &crypto_blkcipher_type;



	if (!(alg->cra_blocksize % 4))

		inst->alg.cra_alignmask |= 3;

	/* We access the data as u32s when xoring. */

	inst->alg.cra_alignmask |= __alignof__(u32) - 1;



	inst->alg.cra_blkcipher.ivsize = alg->cra_blocksize;

	inst->alg.cra_blkcipher.min_keysize = alg->cra_cipher.cia_min_keysize;

	inst->alg.cra_blkcipher.max_keysize = alg->cra_cipher.cia_max_keysize;

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