Add audit system.

Signed-off-by: Pol Henarejos <pol.henarejos@cttc.es>

picokeys_sdk_import.cmake

@@ -342,6 +342,7 @@ list(APPEND PICOKEYS_SOURCES
     ${CMAKE_CURRENT_LIST_DIR}/src/button.c
     ${CMAKE_CURRENT_LIST_DIR}/src/led/led.c
     ${CMAKE_CURRENT_LIST_DIR}/src/signal.c
+    ${CMAKE_CURRENT_LIST_DIR}/src/audit.c
 )
 
 if(ESP_PLATFORM)

src/apdu.h

@@ -34,9 +34,16 @@ extern bool app_exists(const uint8_t *aid, size_t aid_len);
 extern int register_app(int (*)(app_t *, uint8_t), const uint8_t *);
 extern int select_app(const uint8_t *aid, size_t aid_len);
 
+typedef enum {
+    CMD_FLAG_NONE        = 0x00,
+    CMD_FLAG_AUDIT_LOG   = 0x01,
+    CMD_FLAG_CRITICAL    = 0x02,
+} cmd_flags_t;
+
 typedef struct cmd {
     uint8_t ins;
     int (*cmd_handler)(void);
+    cmd_flags_t flags;
 } cmd_t;
 
 extern uint8_t num_apps;

src/audit.c

@@ -0,0 +1,39 @@
+/*
+ * This file is part of the Pico Keys SDK distribution (https://github.com/polhenarejos/pico-keys-sdk).
+ * Copyright (c) 2022 Pol Henarejos.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include "picokeys.h"
+#include "signal.h"
+#include "audit.h"
+
+void audit_entry_set_current_event(uint16_t event) {
+    signal_audit_evt_data_t data = {.cmd = AUDIT_CMD_EVT, .value = event};
+    signal_emit_param(SIGNAL_AUDIT_EVT, &data);
+}
+
+void audit_log_current_entry_with_result(uint16_t result) {
+    signal_audit_evt_data_t data = {.cmd = AUDIT_CMD_LOG, .value = result};
+    signal_emit_param(SIGNAL_AUDIT_EVT, &data);
+}
+
+void audit_entry_set_current_flags(audit_entry_flags_t flags) {
+    signal_audit_evt_data_t data = {.cmd = AUDIT_CMD_SET_FLAGS, .value = flags};
+    signal_emit_param(SIGNAL_AUDIT_EVT, &data);
+}
+void audit_entry_set_current_object(uint16_t object_id) {
+    signal_audit_evt_data_t data = {.cmd = AUDIT_CMD_SET_OBJECT, .value = object_id};
+    signal_emit_param(SIGNAL_AUDIT_EVT, &data);
+}

src/audit.h

@@ -0,0 +1,64 @@
+/*
+ * This file is part of the Pico Keys SDK distribution (https://github.com/polhenarejos/pico-keys-sdk).
+ * Copyright (c) 2022 Pol Henarejos.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#ifndef _AUDIT_H_
+#define _AUDIT_H_
+
+#include <stdint.h>
+
+static const uint8_t SIGNAL_AUDIT_EVT = 10;
+#define AUDIT_EVT_APP_EVT   0x8000
+
+typedef enum {
+    AUDIT_EVT_LOG_READ = 0x0001,
+    AUDIT_EVT_LOG_CLEARED,
+    AUDIT_EVT_FIRMWARE_UPDATE,
+    AUDIT_EVT_INIT,
+    AUDIT_EVT_POWER_UP,
+    AUDIT_EVT_SET_RTC,
+} audit_evt_t;
+
+typedef enum {
+    AUDIT_EF_SUCCESS        = 0x0001,
+    AUDIT_EF_FAIL           = 0x0002,
+    AUDIT_EF_DENIED         = 0x0004,
+
+    AUDIT_EF_USER           = 0x0010,
+    AUDIT_EF_ADMIN          = 0x0020,
+
+    AUDIT_EF_CRITICAL       = 0x0100,
+    AUDIT_EF_TIME_UNSYNCED  = 0x0200,
+} audit_entry_flags_t;
+
+typedef enum {
+    AUDIT_CMD_EVT = 1,
+    AUDIT_CMD_SET_OBJECT = 2,
+    AUDIT_CMD_SET_FLAGS = 3,
+    AUDIT_CMD_LOG = 4
+} audit_cmd_t;
+
+typedef struct {
+    audit_cmd_t cmd;
+    uint16_t value;
+} signal_audit_evt_data_t;
+
+extern void audit_entry_set_current_event(uint16_t event);
+extern void audit_entry_set_current_flags(audit_entry_flags_t flags);
+extern void audit_entry_set_current_object(uint16_t object_id);
+extern void audit_log_current_entry_with_result(uint16_t res);
+
+#endif // _AUDIT_H_

src/main.c

@@ -42,6 +42,7 @@
 #include "pico_time.h"
 #include "serial.h"
 #include "mbedtls/sha256.h"
+#include "signal.h"
 
 app_t apps[16];
 uint8_t num_apps = 0;
@@ -222,6 +223,7 @@ int main(void) {
 #if defined(PICO_RP2350) || defined(ENABLE_EMULATION)
     plugin_init();
 #endif
+    signal_emit(SIGNAL_INIT);
 
 #ifdef ESP_PLATFORM
     xTaskCreatePinnedToCore(core0_loop, "core0", 4096*ITF_TOTAL*2, NULL, CONFIG_TINYUSB_TASK_PRIORITY - 1, &hcore0, ESP32_CORE0);

src/plugin/picokeys_plugin_api.h

@@ -1,16 +1,25 @@
 /*
  * This file is part of the Pico Keys SDK distribution (https://github.com/polhenarejos/pico-keys-sdk).
- * Copyright (c) 2026 Pol Henarejos.
+ * Copyright (c) 2022 Pol Henarejos.
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU Affero General Public License as published by
  * the Free Software Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <https://www.gnu.org/licenses/>.
  */
 
 #ifndef PICOKEYS_PLUGIN_API_H
 #define PICOKEYS_PLUGIN_API_H
 
 #include <stdint.h>
+#include "signal.h"
 
 #if defined(_WIN32)
 #define PICOKEYS_PLUGIN_EXPORT __declspec(dllexport)
@@ -47,16 +56,17 @@ typedef struct pk_plugin_imports {
     uint32_t abi_version;
     uint32_t struct_size;
     int (*printf)(const char *fmt, ...);
+    int (*signal_add)(uint8_t code, signal_flag_t flags, signal_handler_t handler);
 } pk_plugin_imports_t;
 
-typedef void (*pk_plugin_hello_fn)(const pk_plugin_imports_t *imports);
+typedef void (*pk_plugin_init_fn)(const pk_plugin_imports_t *imports);
 
 typedef struct pk_plugin_header {
     uint32_t magic;
     uint32_t abi_version;
     uint32_t header_size;
     uint32_t image_size;
-    pk_plugin_hello_fn hello;
+    pk_plugin_init_fn init;
 } pk_plugin_header_t;
 
 void plugin_init(void);

src/plugin/plugin_loader.c

@@ -1,13 +1,22 @@
 /*
  * This file is part of the Pico Keys SDK distribution (https://github.com/polhenarejos/pico-keys-sdk).
- * Copyright (c) 2026 Pol Henarejos.
+ * Copyright (c) 2022 Pol Henarejos.
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU Affero General Public License as published by
  * the Free Software Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <https://www.gnu.org/licenses/>.
  */
 
 #include "picokeys_plugin_api.h"
+#include "signal.h"
 
 #include <stddef.h>
 #include <stdio.h>
@@ -68,7 +77,7 @@ static const pk_plugin_header_t *pk_plugin_get_valid(void) {
            (unsigned long)plugin->abi_version,
            (unsigned long)plugin->header_size,
            (unsigned long)plugin->image_size,
-           (void *)plugin->hello);
+           (void *)plugin->init);
     if (plugin->magic != PICOKEYS_PLUGIN_MAGIC) {
         printf("Plugin rejected: bad magic\n");
         return NULL;
@@ -81,7 +90,7 @@ static const pk_plugin_header_t *pk_plugin_get_valid(void) {
         printf("Plugin rejected: short header\n");
         return NULL;
     }
-    if (!plugin->hello) {
+    if (!plugin->init) {
         printf("Plugin rejected: missing entry point\n");
         return NULL;
     }
@@ -108,7 +117,7 @@ static const pk_plugin_header_t *pk_plugin_get_valid(void) {
            (unsigned long)plugin->abi_version,
            (unsigned long)plugin->header_size,
            (unsigned long)plugin->image_size,
-           (unsigned long)(uintptr_t)plugin->hello);
+           (unsigned long)(uintptr_t)plugin->init);
     if (plugin->magic != PICOKEYS_PLUGIN_MAGIC) {
         printf("Plugin rejected: bad magic\n");
         return NULL;
@@ -126,8 +135,8 @@ static const pk_plugin_header_t *pk_plugin_get_valid(void) {
         printf("Plugin rejected: bad image size\n");
         return NULL;
     }
-    if (!plugin->hello || !pk_plugin_ptr_in_range((const void *)plugin->hello)) {
-        printf("Plugin rejected: hello pointer out of range\n");
+    if (!plugin->init || !pk_plugin_ptr_in_range((const void *)plugin->init)) {
+        printf("Plugin rejected: init pointer out of range\n");
         return NULL;
     }
     return plugin;
@@ -145,8 +154,7 @@ void plugin_init(void) {
         .abi_version = PICOKEYS_PLUGIN_ABI_VERSION,
         .struct_size = sizeof(imports),
         .printf = printf,
+        .signal_add = signal_add,
     };
-    printf("Calling plugin hello function\n");
-    plugin->hello(&imports);
-    printf("Plugin hello function returned\n");
+    plugin->init(&imports);
 }

src/rescue.c

@@ -31,6 +31,7 @@
 #include "random.h"
 #include "crypto_utils.h"
 #include "usb.h"
+#include "audit.h"
 
 #ifdef PICO_PLATFORM
 extern char __flash_binary_start;
@@ -257,6 +258,7 @@ static int cmd_write(void) {
 #endif
     }
     else if (p1 == 0x2) { // SET TIME
+        audit_entry_set_current_event(AUDIT_EVT_SET_RTC);
         time_t tv_sec = 0;
         if (p2 != 0x1 && p2 != 0x2) {
             return SW_INCORRECT_P1P2();
@@ -405,16 +407,17 @@ static int cmd_reboot_bootsel(void) {
 #define INS_REBOOT_BOOTSEL   0x1F
 
 static const cmd_t cmds[] = {
-    { INS_KEYDEV_SIGN, cmd_keydev_sign },
-    { INS_WRITE, cmd_write },
+    { INS_KEYDEV_SIGN, cmd_keydev_sign, CMD_FLAG_AUDIT_LOG },
+    { INS_WRITE, cmd_write, CMD_FLAG_AUDIT_LOG | CMD_FLAG_CRITICAL },
 #if defined(PICO_RP2350) || defined(ESP_PLATFORM)
-    { INS_SECURE, cmd_secure },
+    { INS_SECURE, cmd_secure, CMD_FLAG_AUDIT_LOG | CMD_FLAG_CRITICAL },
 #endif
-    { INS_READ, cmd_read },
+    { INS_READ, cmd_read, CMD_FLAG_NONE },
 #ifdef PICO_PLATFORM
-    { INS_REBOOT_BOOTSEL, cmd_reboot_bootsel },
+    { INS_REBOOT_BOOTSEL, cmd_reboot_bootsel, CMD_FLAG_NONE },
 #endif
-    { 0x00, 0x0 }
+
+    { 0x00, 0x00, CMD_FLAG_NONE } // End of table
 };
 
 static int rescue_process_apdu(void) {
@@ -423,9 +426,17 @@ static int rescue_process_apdu(void) {
     }
     for (const cmd_t *cmd = cmds; cmd->ins != 0x00; cmd++) {
         if (cmd->ins == INS(apdu)) {
+            audit_entry_set_current_event(AUDIT_EVT_APP_EVT | INS(apdu));
+            audit_entry_set_current_object(make_uint16_be(P1(apdu), P2(apdu)));
             int r = cmd->cmd_handler();
+            if (cmd->flags & CMD_FLAG_AUDIT_LOG) {
+                if (cmd->flags & CMD_FLAG_CRITICAL) {
+                    audit_entry_set_current_flags(AUDIT_EF_CRITICAL);
+                }
+                audit_log_current_entry_with_result(r);
+            }
             return r;
         }
     }
     return SW_INS_NOT_SUPPORTED();
-}
+}