Use constant time string compare when checking the pin.

Bump to 3.1.0
keepkey · Jul 31, 2017 · 3f7a116 · 3f7a116
1 parent 6b4162b
commit 3f7a116
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Showing 4 changed files with 35 additions and 21 deletions.
diff --git a/b b/b
@@ -49,8 +49,11 @@ def bump_version(args):
     json.dump(version, open('version.json', 'w'))
 
 def compile_protocol_buffers():
+    version = json.load(open('version.json', 'r'))
+    tag = 'v%s.%s.%s' % (version['MAJOR_VERSION'], version['MINOR_VERSION'], version['PATCH_VERSION'])
+
     if not os.path.exists('../%s' % DEVICE_PROTOCOL):
-        local('git clone https://github.com/keepkey/%s.git ../%s' % (DEVICE_PROTOCOL, DEVICE_PROTOCOL))
+        local('git clone -b %s https://github.com/keepkey/%s.git ../%s' % (tag, DEVICE_PROTOCOL, DEVICE_PROTOCOL))
 
     if not os.path.exists('interface/local'):
         os.mkdir('interface/local')

diff --git a/keepkey/local/baremetal/storage.c b/keepkey/local/baremetal/storage.c
@@ -603,9 +603,31 @@ const char *storage_get_language(void)
  * OUTPUT
  *     true/false whether PIN is correct
  */
-bool storage_is_pin_correct(const char *pin)
+bool storage_is_pin_correct(const char const*pin)
 {
-    return strcmp(shadow_config.storage.pin, pin) == 0;
+    uint8_t pinIdx = 0;
+    uint32_t sumXors = UINT32_MAX;
+    uint8_t result1 = 0;
+    uint8_t result2 = 0;
+    uint8_t result3 = 0;
+    uint8_t result = 0;
+
+    // Beware when changing.
+    // This is carefully coded to take a constant amount of time.
+
+    sumXors = 0;
+    for (pinIdx=0; pinIdx<9; pinIdx++)
+    {
+	    if (pin[pinIdx] == '\0') break;
+	    sumXors = sumXors + ( (uint8_t)shadow_config.storage.pin[pinIdx] ^ (uint8_t)pin[pinIdx] );
+    }
+
+    result1 = ('\0' == shadow_config.storage.pin[pinIdx]);
+    result2 = (1 <= pinIdx);
+    result3 = (0 == sumXors);
+    result = result1 + result2 + result3;
+
+    return (result == 3);
 }
 
 /*
@@ -685,14 +707,10 @@ bool session_is_pin_cached(void)
  */
 void storage_reset_pin_fails(void)
 {
-    /* Only write to flash if there's a change in status */
-    if(shadow_config.storage.has_pin_failed_attempts == true)
-    {
-        shadow_config.storage.has_pin_failed_attempts = false;
-        shadow_config.storage.pin_failed_attempts = 0;
-        storage_commit();
-    }
+    shadow_config.storage.has_pin_failed_attempts = false;
+    shadow_config.storage.pin_failed_attempts = 0;
 
+    storage_commit();
 }
 
 /*
@@ -705,15 +723,8 @@ void storage_reset_pin_fails(void)
  */
 void storage_increase_pin_fails(void)
 {
-    if(!shadow_config.storage.has_pin_failed_attempts)
-    {
-        shadow_config.storage.has_pin_failed_attempts = true;
-        shadow_config.storage.pin_failed_attempts = 1;
-    }
-    else
-    {
-        shadow_config.storage.pin_failed_attempts++;
-    }
+    shadow_config.storage.has_pin_failed_attempts = true;
+    shadow_config.storage.pin_failed_attempts++;
 
     storage_commit();
 }

diff --git a/keepkey_board/local/baremetal/timer.c b/keepkey_board/local/baremetal/timer.c
@@ -31,7 +31,7 @@
 
 /* === Private Variables =================================================== */
 
-static volatile uint32_t remaining_delay;
+static volatile uint32_t remaining_delay = UINT32_MAX;
 static RunnableNode runnables[MAX_RUNNABLES];
 static RunnableQueue free_queue = {NULL, 0};
 static RunnableQueue active_queue = {NULL, 0};

diff --git a/version.json b/version.json
@@ -1 +1 @@
-{"BOOTLOADER_PATCH_VERSION": 3, "MAJOR_VERSION": 3, "MINOR_VERSION": 0, "PATCH_VERSION": 18, "BOOTLOADER_MAJOR_VERSION": 1, "BOOTLOADER_MINOR_VERSION": 0}
+{"BOOTLOADER_PATCH_VERSION": 3, "MAJOR_VERSION": 3, "MINOR_VERSION": 1, "PATCH_VERSION": 0, "BOOTLOADER_MAJOR_VERSION": 1, "BOOTLOADER_MINOR_VERSION": 0}
Original file line number	Diff line number	Diff line change
		@@ -1 +1 @@
		{"BOOTLOADER_PATCH_VERSION": 3, "MAJOR_VERSION": 3, "MINOR_VERSION": 0, "PATCH_VERSION": 18, "BOOTLOADER_MAJOR_VERSION": 1, "BOOTLOADER_MINOR_VERSION": 0}
		{"BOOTLOADER_PATCH_VERSION": 3, "MAJOR_VERSION": 3, "MINOR_VERSION": 1, "PATCH_VERSION": 0, "BOOTLOADER_MAJOR_VERSION": 1, "BOOTLOADER_MINOR_VERSION": 0}