Add KRB5KDF from RFC 3961

Signed-off-by: Simo Sorce <simo@redhat.com>

Reviewed-by: Tomas Mraz <tmraz@fedoraproject.org>
Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/9949)

1 files changed, 432 insertions, 0 deletions

diff --git a/providers/implementations/kdfs/krb5kdf.c b/providers/implementations/kdfs/krb5kdf.c
new file mode 100644
index 0000000000..83dfa9c2dc
--- /dev/null
+++ b/providers/implementations/kdfs/krb5kdf.c
@@ -0,0 +1,432 @@
+/*
+ * Copyright 2018-2019 The OpenSSL Project Authors. All Rights Reserved.
+ *
+ * Licensed under the OpenSSL license (the "License").  You may not use
+ * this file except in compliance with the License.  You can obtain a copy
+ * in the file LICENSE in the source distribution or at
+ * https://www.openssl.org/source/license.html
+ */
+
+#include <stdlib.h>
+#include <stdarg.h>
+#include <string.h>
+
+#include <openssl/core_names.h>
+#include <openssl/des.h>
+#include <openssl/evp.h>
+#include <openssl/kdf.h>
+
+#include "internal/cryptlib.h"
+#include "crypto/evp.h"
+#include "internal/numbers.h"
+#include "prov/implementations.h"
+#include "prov/provider_ctx.h"
+#include "prov/provider_util.h"
+#include "prov/providercommonerr.h"
+
+/* KRB5 KDF defined in RFC 3961, Section 5.1 */
+
+static OSSL_OP_kdf_newctx_fn krb5kdf_new;
+static OSSL_OP_kdf_freectx_fn krb5kdf_free;
+static OSSL_OP_kdf_reset_fn krb5kdf_reset;
+static OSSL_OP_kdf_derive_fn krb5kdf_derive;
+static OSSL_OP_kdf_settable_ctx_params_fn krb5kdf_settable_ctx_params;
+static OSSL_OP_kdf_set_ctx_params_fn krb5kdf_set_ctx_params;
+static OSSL_OP_kdf_gettable_ctx_params_fn krb5kdf_gettable_ctx_params;
+static OSSL_OP_kdf_get_ctx_params_fn krb5kdf_get_ctx_params;
+
+static int KRB5KDF(const EVP_CIPHER *cipher, ENGINE *engine,
+                   const unsigned char *key, size_t key_len,
+                   const unsigned char *constant, size_t constant_len,
+                   unsigned char *okey, size_t okey_len);
+
+typedef struct {
+    void *provctx;
+    PROV_CIPHER cipher;
+    unsigned char *key;
+    size_t key_len;
+    unsigned char *constant;
+    size_t constant_len;
+} KRB5KDF_CTX;
+
+static void *krb5kdf_new(void *provctx)
+{
+    KRB5KDF_CTX *ctx;
+
+    if ((ctx = OPENSSL_zalloc(sizeof(*ctx))) == NULL)
+        ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
+    ctx->provctx = provctx;
+    return ctx;
+}
+
+static void krb5kdf_free(void *vctx)
+{
+    KRB5KDF_CTX *ctx = (KRB5KDF_CTX *)vctx;
+
+    krb5kdf_reset(ctx);
+    OPENSSL_free(ctx);
+}
+
+static void krb5kdf_reset(void *vctx)
+{
+    KRB5KDF_CTX *ctx = (KRB5KDF_CTX *)vctx;
+
+    ossl_prov_cipher_reset(&ctx->cipher);
+    OPENSSL_clear_free(ctx->key, ctx->key_len);
+    OPENSSL_clear_free(ctx->constant, ctx->constant_len);
+    memset(ctx, 0, sizeof(*ctx));
+}
+
+static int krb5kdf_set_membuf(unsigned char **dst, size_t *dst_len,
+                              const OSSL_PARAM *p)
+{
+    OPENSSL_clear_free(*dst, *dst_len);
+    *dst = NULL;
+    return OSSL_PARAM_get_octet_string(p, (void **)dst, 0, dst_len);
+}
+
+static int krb5kdf_derive(void *vctx, unsigned char *key,
+                              size_t keylen)
+{
+    KRB5KDF_CTX *ctx = (KRB5KDF_CTX *)vctx;
+    const EVP_CIPHER *cipher = ossl_prov_cipher_cipher(&ctx->cipher);
+    ENGINE *engine = ossl_prov_cipher_engine(&ctx->cipher);
+
+    if (cipher == NULL) {
+        ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_CIPHER);
+        return 0;
+    }
+    if (ctx->key == NULL) {
+        ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_KEY);
+        return 0;
+    }
+    if (ctx->constant == NULL) {
+        ERR_raise(ERR_LIB_PROV, PROV_R_MISSING_CONSTANT);
+        return 0;
+    }
+    return KRB5KDF(cipher, engine, ctx->key, ctx->key_len,
+                   ctx->constant, ctx->constant_len,
+                   key, keylen);
+}
+
+static int krb5kdf_set_ctx_params(void *vctx, const OSSL_PARAM params[])
+{
+    const OSSL_PARAM *p;
+    KRB5KDF_CTX *ctx = vctx;
+    OPENSSL_CTX *provctx = PROV_LIBRARY_CONTEXT_OF(ctx->provctx);
+
+    if (!ossl_prov_cipher_load_from_params(&ctx->cipher, params, provctx))
+        return 0;
+
+    if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_KEY)) != NULL)
+        if (!krb5kdf_set_membuf(&ctx->key, &ctx->key_len, p))
+            return 0;
+
+    if ((p = OSSL_PARAM_locate_const(params, OSSL_KDF_PARAM_CONSTANT))
+        != NULL)
+        if (!krb5kdf_set_membuf(&ctx->constant, &ctx->constant_len, p))
+            return 0;
+
+    return 1;
+}
+
+static const OSSL_PARAM *krb5kdf_settable_ctx_params(void)
+{
+    static const OSSL_PARAM known_settable_ctx_params[] = {
+        OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_PROPERTIES, NULL, 0),
+        OSSL_PARAM_utf8_string(OSSL_KDF_PARAM_CIPHER, NULL, 0),
+        OSSL_PARAM_octet_string(OSSL_KDF_PARAM_KEY, NULL, 0),
+        OSSL_PARAM_octet_string(OSSL_KDF_PARAM_CONSTANT, NULL, 0),
+        OSSL_PARAM_END
+    };
+    return known_settable_ctx_params;
+}
+
+static int krb5kdf_get_ctx_params(void *vctx, OSSL_PARAM params[])
+{
+    KRB5KDF_CTX *ctx = (KRB5KDF_CTX *)vctx;
+    const EVP_CIPHER *cipher;
+    size_t len;
+    OSSL_PARAM *p;
+
+    cipher = ossl_prov_cipher_cipher(&ctx->cipher);
+    if (cipher)
+        len = EVP_CIPHER_key_length(cipher);
+    else
+        len = EVP_MAX_KEY_LENGTH;
+
+    if ((p = OSSL_PARAM_locate(params, OSSL_KDF_PARAM_SIZE)) != NULL)
+        return OSSL_PARAM_set_size_t(p, len);
+    return -2;
+}
+
+static const OSSL_PARAM *krb5kdf_gettable_ctx_params(void)
+{
+    static const OSSL_PARAM known_gettable_ctx_params[] = {
+        OSSL_PARAM_size_t(OSSL_KDF_PARAM_SIZE, NULL),
+        OSSL_PARAM_END
+    };
+    return known_gettable_ctx_params;
+}
+
+const OSSL_DISPATCH kdf_krb5kdf_functions[] = {
+    { OSSL_FUNC_KDF_NEWCTX, (void(*)(void))krb5kdf_new },
+    { OSSL_FUNC_KDF_FREECTX, (void(*)(void))krb5kdf_free },
+    { OSSL_FUNC_KDF_RESET, (void(*)(void))krb5kdf_reset },
+    { OSSL_FUNC_KDF_DERIVE, (void(*)(void))krb5kdf_derive },
+    { OSSL_FUNC_KDF_SETTABLE_CTX_PARAMS,
+      (void(*)(void))krb5kdf_settable_ctx_params },
+    { OSSL_FUNC_KDF_SET_CTX_PARAMS,
+      (void(*)(void))krb5kdf_set_ctx_params },
+    { OSSL_FUNC_KDF_GETTABLE_CTX_PARAMS,
+      (void(*)(void))krb5kdf_gettable_ctx_params },
+    { OSSL_FUNC_KDF_GET_CTX_PARAMS,
+      (void(*)(void))krb5kdf_get_ctx_params },
+    { 0, NULL }
+};
+
+#ifndef OPENSSL_NO_DES
+/*
+ * DES3 is a special case, it requires a random-to-key function and its
+ * input truncated to 21 bytes of the 24 produced by the cipher.
+ * See RFC3961 6.3.1
+ */
+static int fixup_des3_key(unsigned char *key)
+{
+    unsigned char *cblock;
+    int i, j;
+
+    for (i = 2; i >= 0; i--) {
+        cblock = &key[i * 8];
+        memmove(cblock, &key[i * 7], 7);
+        cblock[7] = 0;
+        for (j = 0; j < 7; j++)
+            cblock[7] |= (cblock[j] & 1) << (j + 1);
+        DES_set_odd_parity((DES_cblock *)cblock);
+    }
+
+    /* fail if keys are such that triple des degrades to single des */
+    if (CRYPTO_memcmp(&key[0], &key[8], 8) == 0 ||
+        CRYPTO_memcmp(&key[8], &key[16], 8) == 0) {
+        return 0;
+    }
+
+    return 1;
+}
+#endif
+
+/*
+ * N-fold(K) where blocksize is N, and constant_len is K
+ * Note: Here |= denotes concatenation
+ *
+ * L = lcm(N,K)
+ * R = L/K
+ *
+ * for r: 1 -> R
+ *   s |= constant rot 13*(r-1))
+ *
+ * block = 0
+ * for k: 1 -> K
+ *   block += s[N(k-1)..(N-1)k] (one's complement addition)
+ *
+ * Optimizing for space we compute:
+ * for each l in L-1 -> 0:
+ *   s[l] = (constant rot 13*(l/K))[l%k]
+ *   block[l % N] += s[l] (with carry)
+ * finally add carry if any
+ */
+static void n_fold(unsigned char *block, unsigned int blocksize,
+                   const unsigned char *constant, size_t constant_len)
+{
+    unsigned int tmp, gcd, remainder, lcm, carry;
+    int b, l;
+
+    if (constant_len == blocksize) {
+        memcpy(block, constant, constant_len);
+        return;
+    }
+
+    /* Least Common Multiple of lengths: LCM(a,b)*/
+    gcd = blocksize;
+    remainder = constant_len;
+    /* Calculate Great Common Divisor first GCD(a,b) */
+    while (remainder != 0) {
+        tmp = gcd % remainder;
+        gcd = remainder;
+        remainder = tmp;
+    }
+    /* resulting a is the GCD, LCM(a,b) = |a*b|/GCD(a,b) */
+    lcm = blocksize * constant_len / gcd;
+
+    /* now spread out the bits */
+    memset(block, 0, blocksize);
+
+    /* last to first to be able to bring carry forward */
+    carry = 0;
+    for (l = lcm - 1; l >= 0; l--) {
+        unsigned int rotbits, rshift, rbyte;
+
+        /* destination byte in block is l % N */
+        b = l % blocksize;
+        /* Our virtual s buffer is R = L/K long (K = constant_len) */
+        /* So we rotate backwards from R-1 to 0 (none) rotations */
+        rotbits = 13 * (l / constant_len);
+        /* find the byte on s where rotbits falls onto */
+        rbyte = l - (rotbits / 8);
+        /* calculate how much shift on that byte */
+        rshift = rotbits & 0x07;
+        /* rbyte % constant_len gives us the unrotated byte in the
+         * constant buffer, get also the previous byte then
+         * appropriately shift them to get the rotated byte we need */
+        tmp = (constant[(rbyte-1) % constant_len] << (8 - rshift)
+               | constant[rbyte % constant_len] >> rshift)
+              & 0xff;
+        /* add with carry to any value placed by previous passes */
+        tmp += carry + block[b];
+        block[b] = tmp & 0xff;
+        /* save any carry that may be left */
+        carry = tmp >> 8;
+    }
+
+    /* if any carry is left at the end, add it through the number */
+    for (b = blocksize - 1; b >= 0 && carry != 0; b--) {
+        carry += block[b];
+        block[b] = carry & 0xff;
+        carry >>= 8;
+    }
+}
+
+static int cipher_init(EVP_CIPHER_CTX *ctx,
+                       const EVP_CIPHER *cipher, ENGINE *engine,
+                       const unsigned char *key, size_t key_len)
+{
+    int klen, ret;
+
+    ret = EVP_EncryptInit_ex(ctx, cipher, engine, key, NULL);
+    if (!ret)
+        goto out;
+    /* set the key len for the odd variable key len cipher */
+    klen = EVP_CIPHER_CTX_key_length(ctx);
+    if (key_len != (size_t)klen) {
+        ret = EVP_CIPHER_CTX_set_key_length(ctx, key_len);
+        if (!ret)
+            goto out;
+    }
+    /* we never want padding, either the length requested is a multiple of
+     * the cipher block size or we are passed a cipher that can cope with
+     * partial blocks via techniques like cipher text stealing */
+    ret = EVP_CIPHER_CTX_set_padding(ctx, 0);
+    if (!ret)
+        goto out;
+
+out:
+    return ret;
+}
+
+static int KRB5KDF(const EVP_CIPHER *cipher, ENGINE *engine,
+                   const unsigned char *key, size_t key_len,
+                   const unsigned char *constant, size_t constant_len,
+                   unsigned char *okey, size_t okey_len)
+{
+    EVP_CIPHER_CTX *ctx = NULL;
+    unsigned char block[EVP_MAX_BLOCK_LENGTH * 2];
+    unsigned char *plainblock, *cipherblock;
+    size_t blocksize;
+    size_t cipherlen;
+    size_t osize;
+    int des3_no_fixup = 0;
+    int ret;
+
+    if (key_len != okey_len) {
+        /* special case for 3des, where the caller may be requesting
+         * the random raw key, instead of the fixed up key  */
+        if (EVP_CIPHER_nid(cipher) == NID_des_ede3_cbc &&
+            key_len == 24 && okey_len == 21) {
+                des3_no_fixup = 1;
+        } else {
+            ERR_raise(ERR_LIB_PROV, PROV_R_WRONG_OUTPUT_BUFFER_SIZE);
+            return 0;
+        }
+    }
+
+    ctx = EVP_CIPHER_CTX_new();
+    if (ctx == NULL)
+        return 0;
+
+    ret = cipher_init(ctx, cipher, engine, key, key_len);
+    if (!ret)
+        goto out;
+
+    /* Initialize input block */
+    blocksize = EVP_CIPHER_CTX_block_size(ctx);
+
+    if (constant_len > blocksize) {
+        ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_CONSTANT_LENGTH);
+        ret = 0;
+        goto out;
+    }
+
+    n_fold(block, blocksize, constant, constant_len);
+    plainblock = block;
+    cipherblock = block + EVP_MAX_BLOCK_LENGTH;
+
+    for (osize = 0; osize < okey_len; osize += cipherlen) {
+        int olen;
+
+        ret = EVP_EncryptUpdate(ctx, cipherblock, &olen,
+                                plainblock, blocksize);
+        if (!ret)
+            goto out;
+        cipherlen = olen;
+        ret = EVP_EncryptFinal_ex(ctx, cipherblock, &olen);
+        if (!ret)
+            goto out;
+        if (olen != 0) {
+            ERR_raise(ERR_LIB_PROV, PROV_R_WRONG_FINAL_BLOCK_LENGTH);
+            ret = 0;
+            goto out;
+        }
+
+        /* write cipherblock out */
+        if (cipherlen > okey_len - osize)
+            cipherlen = okey_len - osize;
+        memcpy(okey + osize, cipherblock, cipherlen);
+
+        if (okey_len > osize + cipherlen) {
+            /* we need to reinitialize cipher context per spec */
+            ret = EVP_CIPHER_CTX_reset(ctx);
+            if (!ret)
+                goto out;
+            ret = cipher_init(ctx, cipher, engine, key, key_len);
+            if (!ret)
+                goto out;
+
+            /* also swap block offsets so last ciphertext becomes new
+             * plaintext */
+            plainblock = cipherblock;
+            if (cipherblock == block) {
+                cipherblock += EVP_MAX_BLOCK_LENGTH;
+            } else {
+                cipherblock = block;
+            }
+        }
+    }
+
+#ifndef OPENSSL_NO_DES
+    if (EVP_CIPHER_nid(cipher) == NID_des_ede3_cbc && !des3_no_fixup) {
+        ret = fixup_des3_key(okey);
+        if (!ret) {
+            ERR_raise(ERR_LIB_PROV, PROV_R_FAILED_TO_GENERATE_KEY);
+            goto out;
+        }
+    }
+#endif
+
+    ret = 1;
+
+out:
+    EVP_CIPHER_CTX_free(ctx);
+    OPENSSL_cleanse(block, EVP_MAX_BLOCK_LENGTH * 2);
+    return ret;
+}
+