[add] Fetch app name/version from env at startup then stick with it

src/bolos/os.c

@@ -4,14 +4,12 @@
 
 #include "emulate.h"
 #include "svc.h"
+#include "environment.h"
 
 #define OS_SETTING_PLANEMODE_OLD 5
 #define OS_SETTING_PLANEMODE_NEW 6
 #define OS_SETTING_SOUND         9
 
-#define BOLOS_TAG_APPNAME    0x01
-#define BOLOS_TAG_APPVERSION 0x02
-
 #undef PATH_MAX
 #define PATH_MAX 1024
 
@@ -69,56 +67,7 @@ unsigned long sys_os_registry_get_current_app_tag(unsigned int tag,
                                                   uint8_t *buffer,
                                                   size_t length)
 {
-  const char *name;
-  const char *version;
-  const char *str;
-  char *str_dup = NULL;
-
-  if (length < 1) {
-    return 0;
-  }
-
-  name = "app";
-  version = "1.33.7";
-
-  str = getenv("SPECULOS_APPNAME");
-  if (str == NULL) {
-    str = getenv("SPECULOS_DETECTED_APPNAME");
-  }
-
-  if (str != NULL) {
-    str_dup = strdup(str);
-    if (str_dup != NULL) {
-      char *p = strstr(str_dup, ":");
-      if (p != NULL) {
-        *p = '\x00';
-        name = str_dup;
-        version = p + 1;
-      }
-    }
-  }
-
-  switch (tag) {
-  case BOLOS_TAG_APPNAME:
-    strncpy((char *)buffer, name, length);
-    length = MIN(length, strlen(name));
-    break;
-  case BOLOS_TAG_APPVERSION:
-    strncpy((char *)buffer, version, length);
-    length = MIN(length, strlen(version));
-    break;
-  default:
-    length = 0;
-    break;
-  }
-
-  buffer[length] = '\x00';
-
-  if (str_dup != NULL) {
-    free(str_dup);
-  }
-
-  return length;
+    return env_get_app_tag((char *)buffer, length, tag);
 }
 
 unsigned long sys_os_lib_call(unsigned long *call_parameters)

src/environment.c

@@ -30,6 +30,13 @@ static struct {
   uint8_t seed[MAX_SEED_SIZE];
 } actual_seed = { 0 };
 
+/* APP NAME and VERSION */
+static const char *APP_NAME_VERSION_ENV_NAME = "SPECULOS_APPNAME";
+static const char *APP_NAME_VERSION_ENV_NAME_BKP = "SPECULOS_DETECTED_APPNAME";
+
+static env_sized_name_t app_name = { 4, "app\0" };
+static env_sized_name_t app_version = { 7, "1.33.7\0" };
+
 /* RNG VARIABLES */
 
 static const char *RNG_ENV_NAME = "RNG_SEED";
@@ -294,9 +301,66 @@ env_user_certificate_t* env_get_user_certificate(unsigned int index)
   }
 }
 
+static void env_init_app_name_version() {
+  char *str;
+
+  str = getenv(APP_NAME_VERSION_ENV_NAME);
+  if (str == NULL) {
+    str = getenv(APP_NAME_VERSION_ENV_NAME_BKP);
+  }
+
+  if (str == NULL) {
+    warnx("using default app name & version");
+    fprintf(stderr, "[*] Default app name: '%s'\n", app_name.name);
+    fprintf(stderr, "[*] Default app version: '%s'\n", app_version.name);
+    return;
+  }
+
+  char *char_ptr = strchr(str, ':');
+  if (char_ptr == NULL) {
+    warnx("Invalid '<name>:<version>' format in env variable '%s', falling back to default.", str);
+    fprintf(stderr, "[*] Default app name: '%s'\n", app_name.name);
+    fprintf(stderr, "[*] Default app version: '%s'\n", app_version.name);
+    return;
+  }
+
+  // + 1 to include trailing '\0'
+  app_name.length = (char_ptr - str) + 1;
+  app_version.length = (strlen(str) - (size_t)(app_name.length + 1)) + 1 + 1;
+  str[app_name.length - 1] = '\0';
+  strncpy(app_name.name, str, app_name.length);
+  strncpy(app_version.name, str + app_name.length, app_version.length);
+
+  fprintf(stderr, "[*] Env app name: '%s'\n", app_name.name);
+  fprintf(stderr, "[*] Env app version: '%s'\n", app_version.name);
+}
+
+size_t env_get_app_tag(char* dst, size_t length, BOLOS_TAG tag) {
+  env_sized_name_t *field;
+  switch (tag) {
+  case BOLOS_TAG_APPNAME:
+      field = &app_name;
+      break;
+  case BOLOS_TAG_APPVERSION:
+      field = &app_version;
+      break;
+  default:
+      return 0;
+  }
+  if (length < field->length) {
+      warnx("Providing length to copy env variable too small: asked for %u, needs %u",
+            length, field->length);
+      return 0;
+  }
+
+  strncpy(dst, field->name, length);
+  return field->length < length ? field->length : length;
+}
+
 void init_environment()
 {
-    env_init_seed();
-    env_init_rng();
-    env_init_endorsement();
+  env_init_seed();
+  env_init_rng();
+  env_init_endorsement();
+  env_init_app_name_version();
 }

src/environment.h

@@ -3,6 +3,17 @@
 #include <stdint.h>
 
 #define MAX_SEED_SIZE 64
+#define MAX_STRING_SIZE 128
+
+typedef enum {
+    BOLOS_TAG_APPNAME = 0x01,
+    BOLOS_TAG_APPVERSION = 0x02
+} BOLOS_TAG;
+
+typedef struct {
+    size_t length;
+    char name[MAX_STRING_SIZE];
+} env_sized_name_t;
 
 typedef struct {
     uint8_t length;
@@ -13,5 +24,6 @@ size_t env_get_seed(uint8_t *seed, size_t max_size);
 unsigned int env_get_rng();
 cx_ecfp_private_key_t* env_get_user_private_key(unsigned int index);
 env_user_certificate_t* env_get_user_certificate(unsigned int index);
+size_t env_get_app_tag(char* dst, size_t length, BOLOS_TAG tag);
 
 void init_environment();