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author | Ard Biesheuvel <ardb@kernel.org> | 2019-11-08 13:22:34 +0100 |
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committer | Jason A. Donenfeld <Jason@zx2c4.com> | 2022-07-07 13:26:37 +0200 |
commit | 12d875454e14c46cc6a7593ea5c6dfc1945a317d (patch) | |
tree | 3f77eed14c7d2b7ea182927df60788e16f3d8c3f /crypto/curve25519-generic.c | |
parent | 7ea1fb5060412c35694d00270acced7fea5de933 (diff) | |
download | linux-crypto-12d875454e14c46cc6a7593ea5c6dfc1945a317d.tar.gz linux-crypto-12d875454e14c46cc6a7593ea5c6dfc1945a317d.zip |
crypto: curve25519 - implement generic KPP driver
commit 2a22f5c1440006ab3ec53111206094c1048410a2 upstream.
Expose the generic Curve25519 library via the crypto API KPP interface.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Diffstat (limited to '')
-rw-r--r-- | crypto/curve25519-generic.c | 90 |
1 files changed, 90 insertions, 0 deletions
diff --git a/crypto/curve25519-generic.c b/crypto/curve25519-generic.c new file mode 100644 index 00000000..bd88fd57 --- /dev/null +++ b/crypto/curve25519-generic.c @@ -0,0 +1,90 @@ +// SPDX-License-Identifier: GPL-2.0-or-later + +#include <crypto/curve25519.h> +#include <crypto/internal/kpp.h> +#include <crypto/kpp.h> +#include <linux/module.h> +#include <linux/scatterlist.h> + +static int curve25519_set_secret(struct crypto_kpp *tfm, const void *buf, + unsigned int len) +{ + u8 *secret = kpp_tfm_ctx(tfm); + + if (!len) + curve25519_generate_secret(secret); + else if (len == CURVE25519_KEY_SIZE && + crypto_memneq(buf, curve25519_null_point, CURVE25519_KEY_SIZE)) + memcpy(secret, buf, CURVE25519_KEY_SIZE); + else + return -EINVAL; + return 0; +} + +static int curve25519_compute_value(struct kpp_request *req) +{ + struct crypto_kpp *tfm = crypto_kpp_reqtfm(req); + const u8 *secret = kpp_tfm_ctx(tfm); + u8 public_key[CURVE25519_KEY_SIZE]; + u8 buf[CURVE25519_KEY_SIZE]; + int copied, nbytes; + u8 const *bp; + + if (req->src) { + copied = sg_copy_to_buffer(req->src, + sg_nents_for_len(req->src, + CURVE25519_KEY_SIZE), + public_key, CURVE25519_KEY_SIZE); + if (copied != CURVE25519_KEY_SIZE) + return -EINVAL; + bp = public_key; + } else { + bp = curve25519_base_point; + } + + curve25519_generic(buf, secret, bp); + + /* might want less than we've got */ + nbytes = min_t(size_t, CURVE25519_KEY_SIZE, req->dst_len); + copied = sg_copy_from_buffer(req->dst, sg_nents_for_len(req->dst, + nbytes), + buf, nbytes); + if (copied != nbytes) + return -EINVAL; + return 0; +} + +static unsigned int curve25519_max_size(struct crypto_kpp *tfm) +{ + return CURVE25519_KEY_SIZE; +} + +static struct kpp_alg curve25519_alg = { + .base.cra_name = "curve25519", + .base.cra_driver_name = "curve25519-generic", + .base.cra_priority = 100, + .base.cra_module = THIS_MODULE, + .base.cra_ctxsize = CURVE25519_KEY_SIZE, + + .set_secret = curve25519_set_secret, + .generate_public_key = curve25519_compute_value, + .compute_shared_secret = curve25519_compute_value, + .max_size = curve25519_max_size, +}; + +static int curve25519_init(void) +{ + return crypto_register_kpp(&curve25519_alg); +} + +static void curve25519_exit(void) +{ + crypto_unregister_kpp(&curve25519_alg); +} + +subsys_initcall(curve25519_init); +module_exit(curve25519_exit); + +MODULE_ALIAS_CRYPTO("curve25519"); +MODULE_ALIAS_CRYPTO("curve25519-generic"); +MODULE_LICENSE("GPL"); |