fix(blufi): Enhance security in BLUFI example

Author: esp-zhp

examples/bluetooth/blufi/main/blufi_example_main.c

@@ -417,7 +417,7 @@ static void example_event_callback(esp_blufi_cb_event_t event, esp_blufi_cb_para
         BLUFI_INFO("Recv SOFTAP SSID %s, ssid len %d\n", ap_config.ap.ssid, ap_config.ap.ssid_len);
         break;
 	case ESP_BLUFI_EVENT_RECV_SOFTAP_PASSWD:
-        if (param->softap_passwd.passwd_len >= sizeof(ap_config.sta.ssid)/sizeof(ap_config.sta.ssid[0])) {
+        if (param->softap_passwd.passwd_len >= sizeof(ap_config.ap.password)/sizeof(ap_config.ap.password[0])) {
             esp_blufi_send_error_info(ESP_BLUFI_DATA_FORMAT_ERROR);
             BLUFI_INFO("Invalid SOFTAP PASSWD\n");
             break;

examples/bluetooth/blufi/main/blufi_security.c

@@ -41,10 +41,8 @@
 
 struct blufi_security {
 #define DH_SELF_PUB_KEY_LEN     128
-#define DH_SELF_PUB_KEY_BIT_LEN (DH_SELF_PUB_KEY_LEN * 8)
     uint8_t  self_public_key[DH_SELF_PUB_KEY_LEN];
 #define SHARE_KEY_LEN           128
-#define SHARE_KEY_BIT_LEN       (SHARE_KEY_LEN * 8)
     uint8_t  share_key[SHARE_KEY_LEN];
     size_t   share_len;
 #define PSK_LEN                 16
@@ -91,6 +89,7 @@ void blufi_dh_negotiate_data_handler(uint8_t *data, int len, uint8_t **output_da
         }
         blufi_sec->dh_param = (uint8_t *)malloc(blufi_sec->dh_param_len);
         if (blufi_sec->dh_param == NULL) {
+            blufi_sec->dh_param_len = 0;  /* Reset length to avoid using unallocated memory */
             btc_blufi_report_error(ESP_BLUFI_DH_MALLOC_ERROR);
             BLUFI_ERROR("%s, malloc failed\n", __func__);
             return;
@@ -125,9 +124,10 @@ void blufi_dh_negotiate_data_handler(uint8_t *data, int len, uint8_t **output_da
         if (dhm_len > DH_SELF_PUB_KEY_LEN) {
             BLUFI_ERROR("%s dhm len not support %d\n", __func__, dhm_len);
             btc_blufi_report_error(ESP_BLUFI_DH_PARAM_ERROR);
+            return;
         }
 
-        ret = mbedtls_dhm_make_public(&blufi_sec->dhm, dhm_len, blufi_sec->self_public_key, dhm_len, myrand, NULL);
+        ret = mbedtls_dhm_make_public(&blufi_sec->dhm, dhm_len, blufi_sec->self_public_key, DH_SELF_PUB_KEY_LEN, myrand, NULL);
         if (ret) {
             BLUFI_ERROR("%s make public failed %d\n", __func__, ret);
             btc_blufi_report_error(ESP_BLUFI_MAKE_PUBLIC_ERROR);
@@ -136,7 +136,7 @@ void blufi_dh_negotiate_data_handler(uint8_t *data, int len, uint8_t **output_da
 
         ret = mbedtls_dhm_calc_secret( &blufi_sec->dhm,
                 blufi_sec->share_key,
-                SHARE_KEY_BIT_LEN,
+                SHARE_KEY_LEN,
                 &blufi_sec->share_len,
                 myrand, NULL);
         if (ret) {
@@ -153,7 +153,7 @@ void blufi_dh_negotiate_data_handler(uint8_t *data, int len, uint8_t **output_da
             return;
         }
 
-        mbedtls_aes_setkey_enc(&blufi_sec->aes, blufi_sec->psk, 128);
+        mbedtls_aes_setkey_enc(&blufi_sec->aes, blufi_sec->psk, PSK_LEN * 8);
 
         /* alloc output data */
         *output_data = &blufi_sec->self_public_key[0];
@@ -177,6 +177,10 @@ int blufi_aes_encrypt(uint8_t iv8, uint8_t *crypt_data, int crypt_len)
     size_t iv_offset = 0;
     uint8_t iv0[16];
 
+    if (!blufi_sec) {
+        return -1;
+    }
+
     memcpy(iv0, blufi_sec->iv, sizeof(blufi_sec->iv));
     iv0[0] = iv8;   /* set iv8 as the iv0[0] */
 
@@ -194,6 +198,10 @@ int blufi_aes_decrypt(uint8_t iv8, uint8_t *crypt_data, int crypt_len)
     size_t iv_offset = 0;
     uint8_t iv0[16];
 
+    if (!blufi_sec) {
+        return -1;
+    }
+
     memcpy(iv0, blufi_sec->iv, sizeof(blufi_sec->iv));
     iv0[0] = iv8;   /* set iv8 as the iv0[0] */
 
@@ -223,7 +231,7 @@ esp_err_t blufi_security_init(void)
     mbedtls_dhm_init(&blufi_sec->dhm);
     mbedtls_aes_init(&blufi_sec->aes);
 
-    memset(blufi_sec->iv, 0x0, 16);
+    memset(blufi_sec->iv, 0x0, sizeof(blufi_sec->iv));
     return 0;
 }
 
@@ -242,5 +250,5 @@ void blufi_security_deinit(void)
     memset(blufi_sec, 0x0, sizeof(struct blufi_security));
 
     free(blufi_sec);
-    blufi_sec =  NULL;
+    blufi_sec = NULL;
 }