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

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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superseded by an accelerated arch-specific version in the future.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: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Ard Biesheuvel
2019-11-08 13:22:21 +01:00
committed by Herbert Xu
parent ad8f5b8838
commit a1d9306409
4 changed files with 138 additions and 22 deletions
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26
lib/crypto/Kconfig
View File

@@ -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

74
lib/crypto/poly1305.c
View File

@@ -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>");