From aacfb134be2a88211b79dc53bb5bd0e422dbb60d Mon Sep 17 00:00:00 2001 From: Alessandro Ghedini Date: Wed, 2 Mar 2016 23:58:27 +0000 Subject: GH355: Implement HKDF This patch implements the HMAC-based Extract-and-Expand Key Derivation Function (HKDF) as defined in RFC 5869. It is required to implement the QUIC and TLS 1.3 protocols (among others). Signed-off-by: Rich Salz Reviewed-by: Dr. Stephen Henson --- crypto/kdf/Makefile.in | 4 +- crypto/kdf/build.info | 2 +- crypto/kdf/hkdf.c | 332 +++++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 335 insertions(+), 3 deletions(-) create mode 100644 crypto/kdf/hkdf.c (limited to 'crypto/kdf') diff --git a/crypto/kdf/Makefile.in b/crypto/kdf/Makefile.in index 44d57622e0..a1e9584435 100644 --- a/crypto/kdf/Makefile.in +++ b/crypto/kdf/Makefile.in @@ -15,8 +15,8 @@ CFLAGS= $(INCLUDES) $(CFLAG) $(SHARED_CFLAG) GENERAL=Makefile LIB=$(TOP)/libcrypto.a -LIBSRC=tls1_prf.c kdf_err.c -LIBOBJ=tls1_prf.o kdf_err.o +LIBSRC=tls1_prf.c kdf_err.c hkdf.c +LIBOBJ=tls1_prf.o kdf_err.o hkdf.o SRC= $(LIBSRC) diff --git a/crypto/kdf/build.info b/crypto/kdf/build.info index 320f534055..cbe2080ed7 100644 --- a/crypto/kdf/build.info +++ b/crypto/kdf/build.info @@ -1,3 +1,3 @@ LIBS=../../libcrypto SOURCE[../../libcrypto]=\ - tls1_prf.c kdf_err.c + tls1_prf.c kdf_err.c hkdf.c diff --git a/crypto/kdf/hkdf.c b/crypto/kdf/hkdf.c new file mode 100644 index 0000000000..bbe4334fa5 --- /dev/null +++ b/crypto/kdf/hkdf.c @@ -0,0 +1,332 @@ +/* ==================================================================== + * Copyright (c) 2016 The OpenSSL Project. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in + * the documentation and/or other materials provided with the + * distribution. + * + * 3. All advertising materials mentioning features or use of this + * software must display the following acknowledgment: + * "This product includes software developed by the OpenSSL Project + * for use in the OpenSSL Toolkit. (http://www.openssl.org/)" + * + * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to + * endorse or promote products derived from this software without + * prior written permission. For written permission, please contact + * openssl-core@openssl.org. + * + * 5. Products derived from this software may not be called "OpenSSL" + * nor may "OpenSSL" appear in their names without prior written + * permission of the OpenSSL Project. + * + * 6. Redistributions of any form whatsoever must retain the following + * acknowledgment: + * "This product includes software developed by the OpenSSL Project + * for use in the OpenSSL Toolkit (http://www.openssl.org/)" + * + * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY + * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR + * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR + * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; + * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, + * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED + * OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#include +#include +#include +#include +#include +#include "internal/cryptlib.h" +#include "internal/evp_int.h" + +#define HKDF_MAXBUF 1024 + +static unsigned char *HKDF(const EVP_MD *evp_md, + const unsigned char *salt, size_t salt_len, + const unsigned char *key, size_t key_len, + const unsigned char *info, size_t info_len, + unsigned char *okm, size_t okm_len); + +static unsigned char *HKDF_Extract(const EVP_MD *evp_md, + const unsigned char *salt, size_t salt_len, + const unsigned char *key, size_t key_len, + unsigned char *prk, size_t *prk_len); + +static unsigned char *HKDF_Expand(const EVP_MD *evp_md, + const unsigned char *prk, size_t prk_len, + const unsigned char *info, size_t info_len, + unsigned char *okm, size_t okm_len); + +typedef struct { + const EVP_MD *md; + unsigned char *salt; + size_t salt_len; + unsigned char *key; + size_t key_len; + unsigned char info[HKDF_MAXBUF]; + size_t info_len; +} HKDF_PKEY_CTX; + +static int pkey_hkdf_init(EVP_PKEY_CTX *ctx) +{ + HKDF_PKEY_CTX *kctx; + + kctx = OPENSSL_zalloc(sizeof(*kctx)); + if (kctx == NULL) + return 0; + + ctx->data = kctx; + + return 1; +} + +static void pkey_hkdf_cleanup(EVP_PKEY_CTX *ctx) +{ + HKDF_PKEY_CTX *kctx = ctx->data; + OPENSSL_clear_free(kctx->salt, kctx->salt_len); + OPENSSL_clear_free(kctx->key, kctx->key_len); + OPENSSL_cleanse(kctx->info, kctx->info_len); + OPENSSL_free(kctx); +} + +static int pkey_hkdf_ctrl(EVP_PKEY_CTX *ctx, int type, int p1, void *p2) +{ + HKDF_PKEY_CTX *kctx = ctx->data; + + switch (type) { + case EVP_PKEY_CTRL_HKDF_MD: + if (p2 == NULL) + return 0; + + kctx->md = p2; + return 1; + + case EVP_PKEY_CTRL_HKDF_SALT: + if (p1 == 0 || p2 == NULL) + return 1; + + if (p1 < 0) + return 0; + + if (kctx->salt != NULL) + OPENSSL_clear_free(kctx->salt, kctx->salt_len); + + kctx->salt = OPENSSL_memdup(p2, p1); + if (kctx->salt == NULL) + return 0; + + kctx->salt_len = p1; + return 1; + + case EVP_PKEY_CTRL_HKDF_KEY: + if (p1 < 0) + return 0; + + if (kctx->key != NULL) + OPENSSL_clear_free(kctx->key, kctx->key_len); + + kctx->key = OPENSSL_memdup(p2, p1); + if (kctx->key == NULL) + return 0; + + kctx->key_len = p1; + return 1; + + case EVP_PKEY_CTRL_HKDF_INFO: + if (p1 == 0 || p2 == NULL) + return 1; + + if (p1 < 0 || p1 > (int)(HKDF_MAXBUF - kctx->info_len)) + return 0; + + memcpy(kctx->info + kctx->info_len, p2, p1); + kctx->info_len += p1; + return 1; + + default: + return -2; + + } +} + +static int pkey_hkdf_ctrl_str(EVP_PKEY_CTX *ctx, const char *type, + const char *value) +{ + if (strcmp(type, "md") == 0) + return EVP_PKEY_CTX_set_hkdf_md(ctx, EVP_get_digestbyname(value)); + + if (strcmp(type, "salt") == 0) + return EVP_PKEY_CTX_str2ctrl(ctx, EVP_PKEY_CTRL_HKDF_SALT, value); + + if (strcmp(type, "hexsalt") == 0) + return EVP_PKEY_CTX_hex2ctrl(ctx, EVP_PKEY_CTRL_HKDF_SALT, value); + + if (strcmp(type, "key") == 0) + return EVP_PKEY_CTX_str2ctrl(ctx, EVP_PKEY_CTRL_HKDF_KEY, value); + + if (strcmp(type, "hexkey") == 0) + return EVP_PKEY_CTX_hex2ctrl(ctx, EVP_PKEY_CTRL_HKDF_KEY, value); + + if (strcmp(type, "info") == 0) + return EVP_PKEY_CTX_str2ctrl(ctx, EVP_PKEY_CTRL_HKDF_INFO, value); + + if (strcmp(type, "hexinfo") == 0) + return EVP_PKEY_CTX_hex2ctrl(ctx, EVP_PKEY_CTRL_HKDF_INFO, value); + + return -2; +} + +static int pkey_hkdf_derive(EVP_PKEY_CTX *ctx, unsigned char *key, + size_t *keylen) +{ + HKDF_PKEY_CTX *kctx = ctx->data; + + if (kctx->md == NULL || kctx->key == NULL) + return 0; + + if (HKDF(kctx->md, kctx->salt, kctx->salt_len, kctx->key, kctx->key_len, + kctx->info, kctx->info_len, key, *keylen) == NULL) + { + return 0; + } + + return 1; +} + +const EVP_PKEY_METHOD hkdf_pkey_meth = { + EVP_PKEY_HKDF, + 0, + pkey_hkdf_init, + 0, + pkey_hkdf_cleanup, + + 0, 0, + 0, 0, + + 0, + 0, + + 0, + 0, + + 0, 0, + + 0, 0, 0, 0, + + 0, 0, + + 0, 0, + + 0, + pkey_hkdf_derive, + pkey_hkdf_ctrl, + pkey_hkdf_ctrl_str +}; + +static unsigned char *HKDF(const EVP_MD *evp_md, + const unsigned char *salt, size_t salt_len, + const unsigned char *key, size_t key_len, + const unsigned char *info, size_t info_len, + unsigned char *okm, size_t okm_len) +{ + unsigned char prk[EVP_MAX_MD_SIZE]; + size_t prk_len; + + if (!HKDF_Extract(evp_md, salt, salt_len, key, key_len, prk, &prk_len)) + return NULL; + + return HKDF_Expand(evp_md, prk, prk_len, info, info_len, okm, okm_len); +} + +static unsigned char *HKDF_Extract(const EVP_MD *evp_md, + const unsigned char *salt, size_t salt_len, + const unsigned char *key, size_t key_len, + unsigned char *prk, size_t *prk_len) +{ + unsigned int tmp_len; + + if (!HMAC(evp_md, salt, salt_len, key, key_len, prk, &tmp_len)) + return NULL; + + *prk_len = tmp_len; + return prk; +} + +static unsigned char *HKDF_Expand(const EVP_MD *evp_md, + const unsigned char *prk, size_t prk_len, + const unsigned char *info, size_t info_len, + unsigned char *okm, size_t okm_len) +{ + HMAC_CTX *hmac; + + unsigned int i; + + unsigned char prev[EVP_MAX_MD_SIZE]; + + size_t done_len = 0, dig_len = EVP_MD_size(evp_md); + + size_t n = okm_len / dig_len; + if (okm_len % dig_len) + n++; + + if (n > 255) + return NULL; + + if ((hmac = HMAC_CTX_new()) == NULL) + return NULL; + + if (!HMAC_Init_ex(hmac, prk, prk_len, evp_md, NULL)) + goto err; + + for (i = 1; i <= n; i++) { + size_t copy_len; + const unsigned char ctr = i; + + if (i > 1) { + if (!HMAC_Init_ex(hmac, NULL, 0, NULL, NULL)) + goto err; + + if (!HMAC_Update(hmac, prev, dig_len)) + goto err; + } + + if (!HMAC_Update(hmac, info, info_len)) + goto err; + + if (!HMAC_Update(hmac, &ctr, 1)) + goto err; + + if (!HMAC_Final(hmac, prev, NULL)) + goto err; + + copy_len = (done_len + dig_len > okm_len) ? + okm_len - done_len : + dig_len; + + memcpy(okm + done_len, prev, copy_len); + + done_len += copy_len; + } + + HMAC_CTX_free(hmac); + return okm; + + err: + HMAC_CTX_free(hmac); + return NULL; +} -- cgit v1.2.3