Flatten Mbed TLS directory structure

third_party/mbedtls/hkdf.c

@@ -0,0 +1,196 @@
+/* clang-format off */
+
+asm(".ident\t\"\\n\\n\
+Mbed TLS (Apache 2.0)\\n\
+Copyright The Mbed TLS Contributors\"");
+asm(".include \"libc/disclaimer.inc\"");
+
+/*
+ *  HKDF implementation -- RFC 5869
+ *
+ *  Copyright The Mbed TLS Contributors
+ *  SPDX-License-Identifier: Apache-2.0
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License"); you may
+ *  not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+#include "libc/str/str.h"
+#include "third_party/mbedtls/common.h"
+
+#if defined(MBEDTLS_HKDF_C)
+
+#include "third_party/mbedtls/hkdf.h"
+#include "third_party/mbedtls/platform_util.h"
+#include "third_party/mbedtls/error.h"
+
+int mbedtls_hkdf( const mbedtls_md_info_t *md, const unsigned char *salt,
+                  size_t salt_len, const unsigned char *ikm, size_t ikm_len,
+                  const unsigned char *info, size_t info_len,
+                  unsigned char *okm, size_t okm_len )
+{
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
+    unsigned char prk[MBEDTLS_MD_MAX_SIZE];
+
+    ret = mbedtls_hkdf_extract( md, salt, salt_len, ikm, ikm_len, prk );
+
+    if( ret == 0 )
+    {
+        ret = mbedtls_hkdf_expand( md, prk, mbedtls_md_get_size( md ),
+                                   info, info_len, okm, okm_len );
+    }
+
+    mbedtls_platform_zeroize( prk, sizeof( prk ) );
+
+    return( ret );
+}
+
+int mbedtls_hkdf_extract( const mbedtls_md_info_t *md,
+                          const unsigned char *salt, size_t salt_len,
+                          const unsigned char *ikm, size_t ikm_len,
+                          unsigned char *prk )
+{
+    unsigned char null_salt[MBEDTLS_MD_MAX_SIZE] = { '\0' };
+
+    if( salt == NULL )
+    {
+        size_t hash_len;
+
+        if( salt_len != 0 )
+        {
+            return MBEDTLS_ERR_HKDF_BAD_INPUT_DATA;
+        }
+
+        hash_len = mbedtls_md_get_size( md );
+
+        if( hash_len == 0 )
+        {
+            return MBEDTLS_ERR_HKDF_BAD_INPUT_DATA;
+        }
+
+        salt = null_salt;
+        salt_len = hash_len;
+    }
+
+    return( mbedtls_md_hmac( md, salt, salt_len, ikm, ikm_len, prk ) );
+}
+
+int mbedtls_hkdf_expand( const mbedtls_md_info_t *md, const unsigned char *prk,
+                         size_t prk_len, const unsigned char *info,
+                         size_t info_len, unsigned char *okm, size_t okm_len )
+{
+    size_t hash_len;
+    size_t where = 0;
+    size_t n;
+    size_t t_len = 0;
+    size_t i;
+    int ret = 0;
+    mbedtls_md_context_t ctx;
+    unsigned char t[MBEDTLS_MD_MAX_SIZE];
+
+    if( okm == NULL )
+    {
+        return( MBEDTLS_ERR_HKDF_BAD_INPUT_DATA );
+    }
+
+    hash_len = mbedtls_md_get_size( md );
+
+    if( prk_len < hash_len || hash_len == 0 )
+    {
+        return( MBEDTLS_ERR_HKDF_BAD_INPUT_DATA );
+    }
+
+    if( info == NULL )
+    {
+        info = (const unsigned char *) "";
+        info_len = 0;
+    }
+
+    n = okm_len / hash_len;
+
+    if( okm_len % hash_len != 0 )
+    {
+        n++;
+    }
+
+    /*
+     * Per RFC 5869 Section 2.3, okm_len must not exceed
+     * 255 times the hash length
+     */
+    if( n > 255 )
+    {
+        return( MBEDTLS_ERR_HKDF_BAD_INPUT_DATA );
+    }
+
+    mbedtls_md_init( &ctx );
+
+    if( ( ret = mbedtls_md_setup( &ctx, md, 1 ) ) != 0 )
+    {
+        goto exit;
+    }
+
+    memset( t, 0, hash_len );
+
+    /*
+     * Compute T = T(1) | T(2) | T(3) | ... | T(N)
+     * Where T(N) is defined in RFC 5869 Section 2.3
+     */
+    for( i = 1; i <= n; i++ )
+    {
+        size_t num_to_copy;
+        unsigned char c = i & 0xff;
+
+        ret = mbedtls_md_hmac_starts( &ctx, prk, prk_len );
+        if( ret != 0 )
+        {
+            goto exit;
+        }
+
+        ret = mbedtls_md_hmac_update( &ctx, t, t_len );
+        if( ret != 0 )
+        {
+            goto exit;
+        }
+
+        ret = mbedtls_md_hmac_update( &ctx, info, info_len );
+        if( ret != 0 )
+        {
+            goto exit;
+        }
+
+        /* The constant concatenated to the end of each T(n) is a single octet.
+         * */
+        ret = mbedtls_md_hmac_update( &ctx, &c, 1 );
+        if( ret != 0 )
+        {
+            goto exit;
+        }
+
+        ret = mbedtls_md_hmac_finish( &ctx, t );
+        if( ret != 0 )
+        {
+            goto exit;
+        }
+
+        num_to_copy = i != n ? hash_len : okm_len - where;
+        memcpy( okm + where, t, num_to_copy );
+        where += hash_len;
+        t_len = hash_len;
+    }
+
+exit:
+    mbedtls_md_free( &ctx );
+    mbedtls_platform_zeroize( t, sizeof( t ) );
+
+    return( ret );
+}
+
+#endif /* MBEDTLS_HKDF_C */