SolarEnergy/esp32_device/main/jwt.c

115 lines
2.7 KiB
C

#include <string.h>
#include <stdio.h>
#include "jwt.h"
#include "dev_name.h"
#include "crypto.h"
#include "esp_log.h"
static const char *TAG = "jwt";
char *jwt_gen(cJSON *payload)
{
// Generate header
char *kid = dev_name();
if (!kid)
{
ESP_LOGE(TAG, "Failed to allocated memory to store device name!");
return NULL;
}
cJSON *header_json = cJSON_CreateObject();
if (!header_json)
return NULL;
cJSON_AddStringToObject(header_json, "alg", "ES256");
cJSON_AddStringToObject(header_json, "typ", "JWT");
cJSON_AddStringToObject(header_json, "kid", kid);
char *header = cJSON_PrintUnformatted(header_json);
free(kid);
cJSON_Delete(header_json);
if (!header)
{
ESP_LOGE(TAG, "Failed to generate JSON header!");
return NULL;
}
char *header_b64 = crypto_encode_base64_safe_url(header, strlen(header));
free(header);
if (!header_b64)
{
ESP_LOGE(TAG, "Failed to encode header to base64!");
return NULL;
}
// Encode body to JSON
char *body_json = cJSON_PrintUnformatted(payload);
if (!body_json)
{
ESP_LOGE(TAG, "Failed to encode body to JSON!");
free(header_b64);
return NULL;
}
char *body_b64 = crypto_encode_base64_safe_url(body_json, strlen(body_json));
free(body_json);
if (!body_b64)
{
ESP_LOGE(TAG, "Failed to encode body to base64!");
free(header_b64);
return NULL;
}
// Assemble unsigned JWT parts
char *unsigned_jwt = calloc(1, strlen(header_b64) + strlen(body_b64) + 2);
if (!unsigned_jwt)
{
ESP_LOGE(TAG, "Failed to allocate memory to store unsigned JWT!");
free(header_b64);
free(body_b64);
return NULL;
}
sprintf(unsigned_jwt, "%s.%s", header_b64, body_b64);
free(header_b64);
free(body_b64);
size_t sig_len = 0;
char *sig = crypto_sign_sha256_payload(unsigned_jwt, strlen(unsigned_jwt), &sig_len);
if (!sig || sig_len == 0)
{
ESP_LOGE(TAG, "Failed to sign JWT!");
if (sig)
free(sig);
free(unsigned_jwt);
return NULL;
}
char *sig_b64 = crypto_encode_base64_safe_url(sig, sig_len);
free(sig);
if (!sig_b64)
{
ESP_LOGE(TAG, "Failed to encode base64 signature to base64!");
free(unsigned_jwt);
return NULL;
}
char *jwt = calloc(1, 1 + strlen(unsigned_jwt) + 1 + strlen(sig_b64));
if (!jwt)
{
ESP_LOGE(TAG, "Failed to allocate memory to store final JWT!");
free(unsigned_jwt);
free(sig_b64);
return NULL;
}
sprintf(jwt, "%s.%s", unsigned_jwt, sig_b64);
free(unsigned_jwt);
free(sig_b64);
return jwt;
}