From 402edb44d5cf4b83a6d1faadec2234d3fdd4269c Mon Sep 17 00:00:00 2001
From: Pierre Hubert <pierre.git@communiquons.org>
Date: Sat, 27 Jul 2024 16:34:41 +0200
Subject: [PATCH] Start to generate private key

---
 esp32_device/main/crypto.c | 46 ++++++++++++++++++++++++++++++--------
 esp32_device/main/crypto.h |  2 ++
 esp32_device/main/main.c   | 12 +++++-----
 3 files changed, 45 insertions(+), 15 deletions(-)

diff --git a/esp32_device/main/crypto.c b/esp32_device/main/crypto.c
index d48997d..2890ff0 100644
--- a/esp32_device/main/crypto.c
+++ b/esp32_device/main/crypto.c
@@ -1,6 +1,7 @@
 #include "crypto.h"
 #include "system.h"
 
+#include <string.h>
 #include <mbedtls/build_info.h>
 #include <mbedtls/platform.h>
 #include <mbedtls/entropy.h>
@@ -16,6 +17,8 @@
 
 bool crypto_gen_priv_key()
 {
+    // TODO : check if key exists in memory
+
     int ret = 1;
 
     const char *pers = "ecdsa";
@@ -23,11 +26,13 @@ bool crypto_gen_priv_key()
     mbedtls_entropy_context entropy;
     mbedtls_entropy_init(&entropy);
 
-    mbedtls_ecdsa_context ctx_sign;
-    mbedtls_ecdsa_init(&ctx_sign);
+    mbedtls_pk_context key;
+    mbedtls_pk_init(&key);
 
     mbedtls_ctr_drbg_context ctr_drbg;
+    mbedtls_ctr_drbg_init(&ctr_drbg);
 
+    printf("Seed Mbedtls\n");
     if ((ret = mbedtls_ctr_drbg_seed(&ctr_drbg, mbedtls_entropy_func, &entropy,
                                      (const unsigned char *)pers,
                                      strlen(pers))) != 0)
@@ -36,16 +41,39 @@ bool crypto_gen_priv_key()
         reboot();
     }
 
-    // Generate private key
-    if ((ret = mbedtls_ecdsa_genkey(&ctx_sign, ECPARAMS,
-                                    mbedtls_ctr_drbg_random, &ctr_drbg)) != 0)
+    printf("PK info from type\n");
+    if ((ret = mbedtls_pk_setup(&key, mbedtls_pk_info_from_type(MBEDTLS_PK_ECKEY))) != 0)
     {
-        mbedtls_printf(" failed\n  ! mbedtls_ecdsa_genkey returned %d\n", ret);
+        mbedtls_printf(" failed\n  !  mbedtls_pk_setup returned -0x%04x", (unsigned int)-ret);
         reboot();
     }
 
-    mbedtls_pk_context key_ctx;
-    mbedtls_ecp_gen_keypair
+    // Generate private key
+    printf("Generate private key\n");
+    ret = mbedtls_ecp_gen_key(ECPARAMS,
+                              mbedtls_pk_ec(key),
+                              mbedtls_ctr_drbg_random, &ctr_drbg);
+    if (ret != 0)
+    {
+        mbedtls_printf(" failed\n  !  mbedtls_ecp_gen_key returned -0x%04x",
+                       (unsigned int)-ret);
+        reboot();
+    }
 
-    mbedtls_pk_write_key_pem()
+    // Show private key
+    printf("Show private key\n");
+    unsigned char *key_buff = malloc(16000);
+    memset(key_buff, 0, 16000);
+    if ((ret = mbedtls_pk_write_key_pem(&key, key_buff, 16000)) != 0)
+    {
+        mbedtls_printf(" failed\n  !  mbedtls_pk_write_key_pem returned -0x%04x",
+                       (unsigned int)-ret);
+        reboot();
+    }
+
+    printf("%s", key_buff);
+    free(key_buff);
+    printf("done\n");
+
+    return true;
 }
\ No newline at end of file
diff --git a/esp32_device/main/crypto.h b/esp32_device/main/crypto.h
index e53bc04..4f5950f 100644
--- a/esp32_device/main/crypto.h
+++ b/esp32_device/main/crypto.h
@@ -13,6 +13,8 @@ extern "C"
 
     /**
      * Generate device private key, if required
+     *
+     * @returns true if a key was generated, false otherwise
      */
     bool crypto_gen_priv_key();
 
diff --git a/esp32_device/main/main.c b/esp32_device/main/main.c
index 0041e0c..a0334b1 100755
--- a/esp32_device/main/main.c
+++ b/esp32_device/main/main.c
@@ -4,6 +4,7 @@
 #include "dev_name.h"
 #include "storage.h"
 #include "system.h"
+#include "crypto.h"
 
 void app_main(void)
 {
@@ -20,15 +21,14 @@ void app_main(void)
         printf("Generated a new device name\n");
     }
 
+    char *name = dev_name();
+    printf("Dev name: %s\n", name);
+    free(name);
+
     if (crypto_gen_priv_key())
     {
         printf("Generated device private key!\n");
     }
 
-    char *name = dev_name();
-    printf("Dev name: %s\n", name);
-    free(name);
-
-    fflush(stdout);
-    esp_restart();
+    reboot();
 }