Commit a1d93064 authored by Ard Biesheuvel's avatar Ard Biesheuvel Committed by Herbert Xu
Browse files

crypto: poly1305 - expose init/update/final library interface 



Expose the existing generic Poly1305 code via a init/update/final
library interface so that callers are not required to go through
the crypto API's shash abstraction to access it. At the same time,
make some preparations so that the library implementation can be
superseded by an accelerated arch-specific version in the future.

Signed-off-by: default avatarArd Biesheuvel <ardb@kernel.org>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent ad8f5b88

crypto/poly1305_generic.c

+1 −21
Original line number Diff line number Diff line
@@ -85,31 +85,11 @@ EXPORT_SYMBOL_GPL(crypto_poly1305_update); 
int crypto_poly1305_final(struct shash_desc *desc, u8 *dst)

{

	struct poly1305_desc_ctx *dctx = shash_desc_ctx(desc);

	__le32 digest[4];

	u64 f = 0;



	if (unlikely(!dctx->sset))

		return -ENOKEY;



	if (unlikely(dctx->buflen)) {

		dctx->buf[dctx->buflen++] = 1;

		memset(dctx->buf + dctx->buflen, 0,

		       POLY1305_BLOCK_SIZE - dctx->buflen);

		poly1305_core_blocks(&dctx->h, dctx->r, dctx->buf, 1, 0);

	}



	poly1305_core_emit(&dctx->h, digest);



	/* mac = (h + s) % (2^128) */

	f = (f >> 32) + le32_to_cpu(digest[0]) + dctx->s[0];

	put_unaligned_le32(f, dst + 0);

	f = (f >> 32) + le32_to_cpu(digest[1]) + dctx->s[1];

	put_unaligned_le32(f, dst + 4);

	f = (f >> 32) + le32_to_cpu(digest[2]) + dctx->s[2];

	put_unaligned_le32(f, dst + 8);

	f = (f >> 32) + le32_to_cpu(digest[3]) + dctx->s[3];

	put_unaligned_le32(f, dst + 12);



	poly1305_final_generic(dctx, dst);

	return 0;

}

EXPORT_SYMBOL_GPL(crypto_poly1305_final);

include/crypto/poly1305.h

+37 −1
Original line number Diff line number Diff line
@@ -35,7 +35,43 @@ struct poly1305_desc_ctx { 
	/* accumulator */

	struct poly1305_state h;

	/* key */

	struct poly1305_key r[1];

	struct poly1305_key r[CONFIG_CRYPTO_LIB_POLY1305_RSIZE];

};



void poly1305_init_arch(struct poly1305_desc_ctx *desc, const u8 *key);

void poly1305_init_generic(struct poly1305_desc_ctx *desc, const u8 *key);



static inline void poly1305_init(struct poly1305_desc_ctx *desc, const u8 *key)

{

	if (IS_ENABLED(CONFIG_CRYPTO_ARCH_HAVE_LIB_POLY1305))

		poly1305_init_arch(desc, key);

	else

		poly1305_init_generic(desc, key);

}



void poly1305_update_arch(struct poly1305_desc_ctx *desc, const u8 *src,

			  unsigned int nbytes);

void poly1305_update_generic(struct poly1305_desc_ctx *desc, const u8 *src,

			     unsigned int nbytes);



static inline void poly1305_update(struct poly1305_desc_ctx *desc,

				   const u8 *src, unsigned int nbytes)

{

	if (IS_ENABLED(CONFIG_CRYPTO_ARCH_HAVE_LIB_POLY1305))

		poly1305_update_arch(desc, src, nbytes);

	else

		poly1305_update_generic(desc, src, nbytes);

}



void poly1305_final_arch(struct poly1305_desc_ctx *desc, u8 *digest);

void poly1305_final_generic(struct poly1305_desc_ctx *desc, u8 *digest);



static inline void poly1305_final(struct poly1305_desc_ctx *desc, u8 *digest)

{

	if (IS_ENABLED(CONFIG_CRYPTO_ARCH_HAVE_LIB_POLY1305))

		poly1305_final_arch(desc, digest);

	else

		poly1305_final_generic(desc, digest);

}



#endif

lib/crypto/Kconfig

+26 −0
Original line number Diff line number Diff line
@@ -37,8 +37,34 @@ config CRYPTO_LIB_CHACHA 
config CRYPTO_LIB_DES

	tristate



config CRYPTO_LIB_POLY1305_RSIZE

	int

	default 1



config CRYPTO_ARCH_HAVE_LIB_POLY1305

	tristate

	help

	  Declares whether the architecture provides an arch-specific

	  accelerated implementation of the Poly1305 library interface,

	  either builtin or as a module.



config CRYPTO_LIB_POLY1305_GENERIC

	tristate

	help

	  This symbol can be depended upon by arch implementations of the

	  Poly1305 library interface that require the generic code as a

	  fallback, e.g., for SIMD implementations. If no arch specific

	  implementation is enabled, this implementation serves the users

	  of CRYPTO_LIB_POLY1305.



config CRYPTO_LIB_POLY1305

	tristate "Poly1305 library interface"

	depends on CRYPTO_ARCH_HAVE_LIB_POLY1305 || !CRYPTO_ARCH_HAVE_LIB_POLY1305

	select CRYPTO_LIB_POLY1305_GENERIC if CRYPTO_ARCH_HAVE_LIB_POLY1305=n

	help

	  Enable the Poly1305 library interface. This interface may be fulfilled

	  by either the generic implementation or an arch-specific one, if one

	  is available and enabled.



config CRYPTO_LIB_SHA256

	tristate

lib/crypto/poly1305.c

+74 −0
Original line number Diff line number Diff line
@@ -154,5 +154,79 @@ void poly1305_core_emit(const struct poly1305_state *state, void *dst) 
}

EXPORT_SYMBOL_GPL(poly1305_core_emit);



void poly1305_init_generic(struct poly1305_desc_ctx *desc, const u8 *key)

{

	poly1305_core_setkey(desc->r, key);

	desc->s[0] = get_unaligned_le32(key + 16);

	desc->s[1] = get_unaligned_le32(key + 20);

	desc->s[2] = get_unaligned_le32(key + 24);

	desc->s[3] = get_unaligned_le32(key + 28);

	poly1305_core_init(&desc->h);

	desc->buflen = 0;

	desc->sset = true;

	desc->rset = 1;

}

EXPORT_SYMBOL_GPL(poly1305_init_generic);



void poly1305_update_generic(struct poly1305_desc_ctx *desc, const u8 *src,

			     unsigned int nbytes)

{

	unsigned int bytes;



	if (unlikely(desc->buflen)) {

		bytes = min(nbytes, POLY1305_BLOCK_SIZE - desc->buflen);

		memcpy(desc->buf + desc->buflen, src, bytes);

		src += bytes;

		nbytes -= bytes;

		desc->buflen += bytes;



		if (desc->buflen == POLY1305_BLOCK_SIZE) {

			poly1305_core_blocks(&desc->h, desc->r, desc->buf, 1, 1);

			desc->buflen = 0;

		}

	}



	if (likely(nbytes >= POLY1305_BLOCK_SIZE)) {

		poly1305_core_blocks(&desc->h, desc->r, src,

				     nbytes / POLY1305_BLOCK_SIZE, 1);

		src += nbytes - (nbytes % POLY1305_BLOCK_SIZE);

		nbytes %= POLY1305_BLOCK_SIZE;

	}



	if (unlikely(nbytes)) {

		desc->buflen = nbytes;

		memcpy(desc->buf, src, nbytes);

	}

}

EXPORT_SYMBOL_GPL(poly1305_update_generic);



void poly1305_final_generic(struct poly1305_desc_ctx *desc, u8 *dst)

{

	__le32 digest[4];

	u64 f = 0;



	if (unlikely(desc->buflen)) {

		desc->buf[desc->buflen++] = 1;

		memset(desc->buf + desc->buflen, 0,

		       POLY1305_BLOCK_SIZE - desc->buflen);

		poly1305_core_blocks(&desc->h, desc->r, desc->buf, 1, 0);

	}



	poly1305_core_emit(&desc->h, digest);



	/* mac = (h + s) % (2^128) */

	f = (f >> 32) + le32_to_cpu(digest[0]) + desc->s[0];

	put_unaligned_le32(f, dst + 0);

	f = (f >> 32) + le32_to_cpu(digest[1]) + desc->s[1];

	put_unaligned_le32(f, dst + 4);

	f = (f >> 32) + le32_to_cpu(digest[2]) + desc->s[2];

	put_unaligned_le32(f, dst + 8);

	f = (f >> 32) + le32_to_cpu(digest[3]) + desc->s[3];

	put_unaligned_le32(f, dst + 12);



	*desc = (struct poly1305_desc_ctx){};

}

EXPORT_SYMBOL_GPL(poly1305_final_generic);



MODULE_LICENSE("GPL");

MODULE_AUTHOR("Martin Willi <martin@strongswan.org>");

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