Add X9.42 KDF.

Move the KDF code for CMS DH key agreement into an EVP_KDF object.
There are 2 specifications for X9.42 KDF. This implementation uses DER for
otherinfo which embeds the KDF loop counter inside the DER object.

Reviewed-by: Tomas Mraz <tmraz@fedoraproject.org>
Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Paul Dale <paul.dale@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/8898)

3 files changed, 419 insertions, 1 deletions

diff --git a/crypto/kdf/build.info b/crypto/kdf/build.info
index 52e40a4f2f..4fdaccddec 100644
--- a/crypto/kdf/build.info
+++ b/crypto/kdf/build.info
@@ -1,4 +1,4 @@
 LIBS=../../libcrypto
 SOURCE[../../libcrypto]=\
         tls1_prf.c kdf_err.c kdf_util.c hkdf.c scrypt.c pbkdf2.c sshkdf.c \
-        sskdf.c
+        sskdf.c x942kdf.c
diff --git a/crypto/kdf/kdf_err.c b/crypto/kdf/kdf_err.c
index 98dc271efc..1b6e7845eb 100644
--- a/crypto/kdf/kdf_err.c
+++ b/crypto/kdf/kdf_err.c
@@ -67,17 +67,26 @@ static const ERR_STRING_DATA KDF_str_functs[] = {
     {ERR_PACK(ERR_LIB_KDF, KDF_F_SSKDF_NEW, 0), "sskdf_new"},
     {ERR_PACK(ERR_LIB_KDF, KDF_F_SSKDF_SIZE, 0), "sskdf_size"},
     {ERR_PACK(ERR_LIB_KDF, KDF_F_TLS1_PRF_ALG, 0), "tls1_prf_alg"},
+    {ERR_PACK(ERR_LIB_KDF, KDF_F_X942KDF_CTRL, 0), "x942kdf_ctrl"},
+    {ERR_PACK(ERR_LIB_KDF, KDF_F_X942KDF_DERIVE, 0), "x942kdf_derive"},
+    {ERR_PACK(ERR_LIB_KDF, KDF_F_X942KDF_HASH_KDM, 0), "x942kdf_hash_kdm"},
+    {ERR_PACK(ERR_LIB_KDF, KDF_F_X942KDF_NEW, 0), "x942kdf_new"},
+    {ERR_PACK(ERR_LIB_KDF, KDF_F_X942KDF_SIZE, 0), "x942kdf_size"},
     {ERR_PACK(ERR_LIB_KDF, KDF_F_X963KDF_DERIVE, 0), "x963kdf_derive"},
     {0, NULL}
 };
 
 static const ERR_STRING_DATA KDF_str_reasons[] = {
+    {ERR_PACK(ERR_LIB_KDF, 0, KDF_R_BAD_ENCODING), "bad encoding"},
+    {ERR_PACK(ERR_LIB_KDF, 0, KDF_R_BAD_LENGTH), "bad length"},
+    {ERR_PACK(ERR_LIB_KDF, 0, KDF_R_INAVLID_UKM_LEN), "inavlid ukm len"},
     {ERR_PACK(ERR_LIB_KDF, 0, KDF_R_INVALID_DIGEST), "invalid digest"},
     {ERR_PACK(ERR_LIB_KDF, 0, KDF_R_INVALID_ITERATION_COUNT),
     "invalid iteration count"},
     {ERR_PACK(ERR_LIB_KDF, 0, KDF_R_INVALID_KEY_LEN), "invalid key len"},
     {ERR_PACK(ERR_LIB_KDF, 0, KDF_R_INVALID_MAC_TYPE), "invalid mac type"},
     {ERR_PACK(ERR_LIB_KDF, 0, KDF_R_INVALID_SALT_LEN), "invalid salt len"},
+    {ERR_PACK(ERR_LIB_KDF, 0, KDF_R_MISSING_CEK_ALG), "missing cek alg"},
     {ERR_PACK(ERR_LIB_KDF, 0, KDF_R_MISSING_ITERATION_COUNT),
     "missing iteration count"},
     {ERR_PACK(ERR_LIB_KDF, 0, KDF_R_MISSING_KEY), "missing key"},
@@ -94,6 +103,8 @@ static const ERR_STRING_DATA KDF_str_reasons[] = {
     {ERR_PACK(ERR_LIB_KDF, 0, KDF_R_NOT_SUPPORTED), "not supported"},
     {ERR_PACK(ERR_LIB_KDF, 0, KDF_R_UNKNOWN_PARAMETER_TYPE),
     "unknown parameter type"},
+    {ERR_PACK(ERR_LIB_KDF, 0, KDF_R_UNSUPPORTED_CEK_ALG),
+    "unsupported cek alg"},
     {ERR_PACK(ERR_LIB_KDF, 0, KDF_R_UNSUPPORTED_MAC_TYPE),
     "unsupported mac type"},
     {ERR_PACK(ERR_LIB_KDF, 0, KDF_R_VALUE_ERROR), "value error"},
diff --git a/crypto/kdf/x942kdf.c b/crypto/kdf/x942kdf.c
new file mode 100644
index 0000000000..ce9ad61035
--- /dev/null
+++ b/crypto/kdf/x942kdf.c
@@ -0,0 +1,407 @@
+/*
+ * Copyright 2019 The OpenSSL Project Authors. All Rights Reserved.
+ * Copyright (c) 2019, Oracle and/or its affiliates.  All rights reserved.
+ *
+ * Licensed under the Apache License 2.0 (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 "e_os.h"
+
+#ifndef OPENSSL_NO_CMS
+
+# include <stdlib.h>
+# include <stdarg.h>
+# include <string.h>
+# include <openssl/hmac.h>
+# include <openssl/cms.h>
+# include <openssl/evp.h>
+# include <openssl/kdf.h>
+# include <openssl/x509.h>
+# include <openssl/obj_mac.h>
+# include "internal/cryptlib.h"
+# include "internal/evp_int.h"
+# include "kdf_local.h"
+
+# define X942KDF_MAX_INLEN (1 << 30)
+
+struct evp_kdf_impl_st {
+    const EVP_MD *md;
+    unsigned char *secret;
+    size_t secret_len;
+    int cek_nid;
+    unsigned char *ukm;
+    size_t ukm_len;
+    size_t dkm_len;
+};
+
+/* A table of allowed wrapping algorithms and the associated output lengths */
+static const struct {
+    int nid;
+    size_t keklen; /* size in bytes */
+} kek_algs[] = {
+    { NID_id_smime_alg_CMS3DESwrap, 24 },
+    { NID_id_smime_alg_CMSRC2wrap, 16 },
+    { NID_id_aes128_wrap, 16 },
+    { NID_id_aes192_wrap, 24 },
+    { NID_id_aes256_wrap, 32 },
+    { NID_id_camellia128_wrap, 16 },
+    { NID_id_camellia192_wrap, 24 },
+    { NID_id_camellia256_wrap, 32 }
+};
+
+/* Skip past an ASN1 structure: for OBJECT skip content octets too */
+static int skip_asn1(unsigned char **pp, long *plen, int exptag)
+{
+    int i, tag, xclass;
+    long tmplen;
+    const unsigned char *q = *pp;
+
+    i = ASN1_get_object(&q, &tmplen, &tag, &xclass, *plen);
+    if ((i & 0x80) != 0 || tag != exptag || xclass != V_ASN1_UNIVERSAL)
+        return 0;
+    if (tag == V_ASN1_OBJECT)
+        q += tmplen;
+    *pp = (unsigned char *)q;
+    *plen -= q - *pp;
+    return 1;
+}
+
+/*
+ * Encode the other info structure.
+ *
+ *  RFC2631 Section 2.1.2 Contains the following definition for otherinfo
+ *
+ *  OtherInfo ::= SEQUENCE {
+ *      keyInfo KeySpecificInfo,
+ *      partyAInfo [0] OCTET STRING OPTIONAL,
+ *      suppPubInfo [2] OCTET STRING
+ *  }
+ *
+ *  KeySpecificInfo ::= SEQUENCE {
+ *      algorithm OBJECT IDENTIFIER,
+ *      counter OCTET STRING SIZE (4..4)
+ *  }
+ *
+ * |nid| is the algorithm object identifier.
+ * |keylen| is the length (in bytes) of the generated KEK. It is stored into
+ * suppPubInfo (in bits).
+ * |ukm| is the optional user keying material that is stored into partyAInfo. It
+ * can be NULL.
+ * |ukmlen| is the user keying material length (in bytes).
+ * |der| is the returned encoded data. It must be freed by the caller.
+ * |der_len| is the returned size of the encoded data.
+ * |out_ctr| returns a pointer to the counter data which is embedded inside the
+ * encoded data. This allows the counter bytes to be updated without re-encoding.
+ *
+ * Returns: 1 if successfully encoded, or 0 otherwise.
+ * Assumptions: |der|, |der_len| & |out_ctr| are not NULL.
+ */
+static int x942_encode_otherinfo(int nid, size_t keylen,
+                                 const unsigned char *ukm, size_t ukmlen,
+                                 unsigned char **der, size_t *der_len,
+                                 unsigned char **out_ctr)
+{
+    unsigned char *p, *encoded = NULL;
+    int ret = 0, encoded_len;
+    long tlen;
+    /* "magic" value to check offset is sane */
+    static unsigned char ctr[4] = { 0x00, 0x00, 0x00, 0x01 };
+    X509_ALGOR *ksi = NULL;
+    ASN1_OBJECT *alg_oid = NULL;
+    ASN1_OCTET_STRING *ctr_oct = NULL, *ukm_oct = NULL;
+
+    /* set the KeySpecificInfo - which contains an algorithm oid and counter */
+    ksi = X509_ALGOR_new();
+    alg_oid = OBJ_dup(OBJ_nid2obj(nid));
+    ctr_oct = ASN1_OCTET_STRING_new();
+    if (ksi == NULL
+        || alg_oid == NULL
+        || ctr_oct == NULL
+        || !ASN1_OCTET_STRING_set(ctr_oct, ctr, sizeof(ctr))
+        || !X509_ALGOR_set0(ksi, alg_oid, V_ASN1_OCTET_STRING, ctr_oct))
+        goto err;
+    /* NULL these as they now belong to ksi */
+    alg_oid = NULL;
+    ctr_oct = NULL;
+
+    /* Set the optional partyAInfo */
+    if (ukm != NULL) {
+        ukm_oct = ASN1_OCTET_STRING_new();
+        if (ukm_oct == NULL)
+            goto err;
+        ASN1_OCTET_STRING_set(ukm_oct, (unsigned char *)ukm, ukmlen);
+    }
+    /* Generate the OtherInfo DER data */
+    encoded_len = CMS_SharedInfo_encode(&encoded, ksi, ukm_oct, keylen);
+    if (encoded_len <= 0)
+        goto err;
+
+    /* Parse the encoded data to find the offset of the counter data */
+    p = encoded;
+    tlen = (long)encoded_len;
+    if (skip_asn1(&p, &tlen, V_ASN1_SEQUENCE)
+        && skip_asn1(&p, &tlen, V_ASN1_SEQUENCE)
+        && skip_asn1(&p, &tlen, V_ASN1_OBJECT)
+        && skip_asn1(&p, &tlen, V_ASN1_OCTET_STRING)
+        && CRYPTO_memcmp(p, ctr, 4) == 0) {
+        *out_ctr = p;
+        *der = encoded;
+        *der_len = (size_t)encoded_len;
+        ret = 1;
+    }
+err:
+    if (ret != 1)
+        OPENSSL_free(encoded);
+    ASN1_OCTET_STRING_free(ctr_oct);
+    ASN1_OCTET_STRING_free(ukm_oct);
+    ASN1_OBJECT_free(alg_oid);
+    X509_ALGOR_free(ksi);
+    return ret;
+}
+
+static int x942kdf_hash_kdm(const EVP_MD *kdf_md,
+                            const unsigned char *z, size_t z_len,
+                            const unsigned char *other, size_t other_len,
+                            unsigned char *ctr,
+                            unsigned char *derived_key, size_t derived_key_len)
+{
+    int ret = 0, hlen;
+    size_t counter, out_len, len = derived_key_len;
+    unsigned char mac[EVP_MAX_MD_SIZE];
+    unsigned char *out = derived_key;
+    EVP_MD_CTX *ctx = NULL, *ctx_init = NULL;
+
+    if (z_len > X942KDF_MAX_INLEN || other_len > X942KDF_MAX_INLEN
+            || derived_key_len > X942KDF_MAX_INLEN
+            || derived_key_len == 0) {
+        KDFerr(KDF_F_X942KDF_HASH_KDM, KDF_R_BAD_LENGTH);
+        return 0;
+    }
+
+    hlen = EVP_MD_size(kdf_md);
+    if (hlen <= 0)
+        return 0;
+    out_len = (size_t)hlen;
+
+    ctx = EVP_MD_CTX_create();
+    ctx_init = EVP_MD_CTX_create();
+    if (ctx == NULL || ctx_init == NULL)
+        goto end;
+
+    if (!EVP_DigestInit(ctx_init, kdf_md))
+        goto end;
+
+    for (counter = 1;; counter++) {
+        /* updating the ctr modifies 4 bytes in the 'other' buffer */
+        ctr[0] = (unsigned char)((counter >> 24) & 0xff);
+        ctr[1] = (unsigned char)((counter >> 16) & 0xff);
+        ctr[2] = (unsigned char)((counter >> 8) & 0xff);
+        ctr[3] = (unsigned char)(counter & 0xff);
+
+        if (!EVP_MD_CTX_copy_ex(ctx, ctx_init)
+            || !EVP_DigestUpdate(ctx, z, z_len)
+            || !EVP_DigestUpdate(ctx, other, other_len))
+            goto end;
+        if (len >= out_len) {
+            if (!EVP_DigestFinal_ex(ctx, out, NULL))
+                goto end;
+            out += out_len;
+            len -= out_len;
+            if (len == 0)
+                break;
+        } else {
+            if (!EVP_DigestFinal_ex(ctx, mac, NULL))
+                goto end;
+            memcpy(out, mac, len);
+            break;
+        }
+    }
+    ret = 1;
+end:
+    EVP_MD_CTX_free(ctx);
+    EVP_MD_CTX_free(ctx_init);
+    OPENSSL_cleanse(mac, sizeof(mac));
+    return ret;
+}
+
+static EVP_KDF_IMPL *x942kdf_new(void)
+{
+    EVP_KDF_IMPL *impl;
+
+    if ((impl = OPENSSL_zalloc(sizeof(*impl))) == NULL)
+        KDFerr(KDF_F_X942KDF_NEW, ERR_R_MALLOC_FAILURE);
+    return impl;
+}
+
+static void x942kdf_reset(EVP_KDF_IMPL *impl)
+{
+    OPENSSL_clear_free(impl->secret, impl->secret_len);
+    OPENSSL_clear_free(impl->ukm, impl->ukm_len);
+    memset(impl, 0, sizeof(*impl));
+}
+
+static void x942kdf_free(EVP_KDF_IMPL *impl)
+{
+    x942kdf_reset(impl);
+    OPENSSL_free(impl);
+}
+
+static int x942kdf_set_buffer(va_list args, unsigned char **out, size_t *out_len)
+{
+    const unsigned char *p;
+    size_t len;
+
+    p = va_arg(args, const unsigned char *);
+    len = va_arg(args, size_t);
+    if (len == 0 || p == NULL)
+        return 1;
+
+    OPENSSL_free(*out);
+    *out = OPENSSL_memdup(p, len);
+    if (*out == NULL)
+        return 0;
+
+    *out_len = len;
+    return 1;
+}
+
+static int x942kdf_ctrl(EVP_KDF_IMPL *impl, int cmd, va_list args)
+{
+    const EVP_MD *md;
+    char *alg_str = NULL;
+    size_t i;
+
+    switch (cmd) {
+    case EVP_KDF_CTRL_SET_MD:
+        md = va_arg(args, const EVP_MD *);
+        if (md == NULL)
+            return 0;
+
+        impl->md = md;
+        return 1;
+
+    case EVP_KDF_CTRL_SET_KEY:
+        return x942kdf_set_buffer(args, &impl->secret, &impl->secret_len);
+
+    case EVP_KDF_CTRL_SET_UKM:
+        return x942kdf_set_buffer(args, &impl->ukm, &impl->ukm_len);
+
+    case EVP_KDF_CTRL_SET_CEK_ALG:
+        alg_str = va_arg(args, char *);
+        if (alg_str == NULL)
+            return 0;
+        impl->cek_nid = OBJ_sn2nid(alg_str);
+        for (i = 0; i < (size_t)OSSL_NELEM(kek_algs); ++i) {
+            if (kek_algs[i].nid == impl->cek_nid) {
+                impl->dkm_len = kek_algs[i].keklen;
+                return 1;
+            }
+        }
+        KDFerr(KDF_F_X942KDF_CTRL, KDF_R_UNSUPPORTED_CEK_ALG);
+        return 0;
+
+    default:
+        return -2;
+    }
+}
+
+static int x942kdf_ctrl_str(EVP_KDF_IMPL *impl, const char *type,
+                            const char *value)
+{
+    if (strcmp(type, "digest") == 0)
+        return kdf_md2ctrl(impl, x942kdf_ctrl, EVP_KDF_CTRL_SET_MD, value);
+
+    if (strcmp(type, "secret") == 0 || strcmp(type, "key") == 0)
+         return kdf_str2ctrl(impl, x942kdf_ctrl, EVP_KDF_CTRL_SET_KEY,
+                             value);
+
+    if (strcmp(type, "hexsecret") == 0 || strcmp(type, "hexkey") == 0)
+        return kdf_hex2ctrl(impl, x942kdf_ctrl, EVP_KDF_CTRL_SET_KEY,
+                            value);
+
+    if (strcmp(type, "ukm") == 0)
+        return kdf_str2ctrl(impl, x942kdf_ctrl, EVP_KDF_CTRL_SET_UKM,
+                            value);
+
+    if (strcmp(type, "hexukm") == 0)
+        return kdf_hex2ctrl(impl, x942kdf_ctrl, EVP_KDF_CTRL_SET_UKM,
+                            value);
+
+    if (strcmp(type, "cekalg") == 0)
+        return kdf_str2ctrl(impl, x942kdf_ctrl, EVP_KDF_CTRL_SET_CEK_ALG,
+                            value);
+
+    return -2;
+}
+
+static size_t x942kdf_size(EVP_KDF_IMPL *impl)
+{
+    int len;
+
+    if (impl->md == NULL) {
+        KDFerr(KDF_F_X942KDF_SIZE, KDF_R_MISSING_MESSAGE_DIGEST);
+        return 0;
+    }
+    len = EVP_MD_size(impl->md);
+    return (len <= 0) ? 0 : (size_t)len;
+}
+
+static int x942kdf_derive(EVP_KDF_IMPL *impl, unsigned char *key, size_t keylen)
+{
+    int ret = 0;
+    unsigned char *ctr;
+    unsigned char *der = NULL;
+    size_t der_len = 0;
+
+    if (impl->secret == NULL) {
+        KDFerr(KDF_F_X942KDF_DERIVE, KDF_R_MISSING_SECRET);
+        return 0;
+    }
+    if (impl->md == NULL) {
+        KDFerr(KDF_F_X942KDF_DERIVE, KDF_R_MISSING_MESSAGE_DIGEST);
+        return 0;
+    }
+    if (impl->cek_nid == NID_undef) {
+        KDFerr(KDF_F_X942KDF_DERIVE, KDF_R_MISSING_CEK_ALG);
+        return 0;
+    }
+    if (impl->ukm != NULL && impl->ukm_len >= X942KDF_MAX_INLEN) {
+        /*
+         * Note the ukm length MUST be 512 bits.
+         * For backwards compatibility the old check is being done.
+         */
+        KDFerr(KDF_F_X942KDF_DERIVE, KDF_R_INAVLID_UKM_LEN);
+        return 0;
+    }
+    if (keylen != impl->dkm_len) {
+        KDFerr(KDF_F_X942KDF_DERIVE, KDF_R_MISSING_CEK_ALG);
+        return 0;
+    }
+    /* generate the otherinfo der */
+    if (!x942_encode_otherinfo(impl->cek_nid, impl->dkm_len,
+                               impl->ukm, impl->ukm_len,
+                               &der, &der_len, &ctr)) {
+        KDFerr(KDF_F_X942KDF_DERIVE, KDF_R_BAD_ENCODING);
+        return 0;
+    }
+    ret = x942kdf_hash_kdm(impl->md, impl->secret, impl->secret_len,
+                           der, der_len, ctr, key, keylen);
+    OPENSSL_free(der);
+    return ret;
+}
+
+const EVP_KDF x942_kdf_meth = {
+    EVP_KDF_X942,
+    x942kdf_new,
+    x942kdf_free,
+    x942kdf_reset,
+    x942kdf_ctrl,
+    x942kdf_ctrl_str,
+    x942kdf_size,
+    x942kdf_derive
+};
+
+#endif /* OPENSSL_NO_CMS */