Squashed 'lib/mbedtls/external/mbedtls/' content from commit 2ca6c285a0dd

git-subtree-dir: lib/mbedtls/external/mbedtls
git-subtree-split: 2ca6c285a0dd3f33982dd57299012dacab1ff206

1 files changed, 161 insertions, 0 deletions

diff --git a/library/hkdf.c b/library/hkdf.c
new file mode 100644
index 00000000000..631ac24e530
--- /dev/null
+++ b/library/hkdf.c
@@ -0,0 +1,161 @@
+/*
+ *  HKDF implementation -- RFC 5869
+ *
+ *  Copyright The Mbed TLS Contributors
+ *  SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
+ */
+#include "common.h"
+
+#if defined(MBEDTLS_HKDF_C)
+
+#include <string.h>
+#include "mbedtls/hkdf.h"
+#include "mbedtls/platform_util.h"
+#include "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 */