fix signature check

Author: tobozo

src/esp32FOTA.cpp

@@ -441,23 +441,22 @@ bool esp32FOTA::execOTA( int partition, bool restart_after )
     mode_z = F_isZlibStream();
 
     log_d("compression: %s", mode_z ? "enabled" : "disabled" );
-    // If using compression, the size is implicitely unknown
-    size_t fwsize = mode_z ? UPDATE_SIZE_UNKNOWN : updateSize;       // fw_size is unknown if we have a compressed image
 
     if( _cfg.check_sig ) {
       if( mode_z ) {
         Serial.println("[ERROR] Compressed && signed image is not (yet) supported");
         return false;
       }
-      if( updateSize != UPDATE_SIZE_UNKNOWN ) {
-        if( updateSize <= FW_SIGNATURE_LENGTH ) {
+      if( updateSize == UPDATE_SIZE_UNKNOWN || updateSize <= FW_SIGNATURE_LENGTH ) {
           Serial.println("[ERROR] Malformed signature+fw combo");
           return false;
-        }
-        updateSize -= FW_SIGNATURE_LENGTH;
       }
+      updateSize -= FW_SIGNATURE_LENGTH;
     }
 
+    // If using compression, the size is implicitely unknown
+    size_t fwsize = mode_z ? UPDATE_SIZE_UNKNOWN : updateSize;       // fw_size is unknown if we have a compressed image
+
     bool canBegin = F_canBegin();
 
     if( !canBegin ) {

src/esp32FOTA.hpp

@@ -80,7 +80,7 @@ extern "C" {
   #define F_Update FlashZ::getInstance()
   #define F_hasZlib() true
   #define F_isZlibStream() (_stream->peek() == ZLIB_HEADER && ((partition == U_SPIFFS && _flashFileSystemUrl.indexOf("zz")>-1) || (partition == U_FLASH && _firmwareUrl.indexOf("zz")>-1)))
-  #define F_canBegin() (mode_z ? F_Update.beginz(UPDATE_SIZE_UNKNOWN, partition) : F_Update.begin(fwsize, partition))
+  #define F_canBegin() (mode_z ? F_Update.beginz(UPDATE_SIZE_UNKNOWN, partition) : F_Update.begin(updateSize, partition))
   #define F_UpdateEnd() (mode_z ? F_Update.endz() : F_Update.end())
   #define F_abort() if (mode_z) F_Update.abortz(); else F_Update.abort()
   #define F_writeStream() (mode_z ? F_Update.writezStream(*_stream, updateSize) : F_Update.writeStream(*_stream))
@@ -91,7 +91,7 @@ extern "C" {
   #define F_Update GzUpdateClass::getInstance()
   #define F_hasZlib() true
   #define F_isZlibStream() (_stream->peek() == 0x1f && ((partition == U_SPIFFS && _flashFileSystemUrl.indexOf("gz")>-1) || (partition == U_FLASH && _firmwareUrl.indexOf("gz")>-1)) )
-  #define F_canBegin() (mode_z ? F_Update.begingz(UPDATE_SIZE_UNKNOWN, partition) : F_Update.begin(fwsize, partition))
+  #define F_canBegin() (mode_z ? F_Update.begingz(UPDATE_SIZE_UNKNOWN, partition) : F_Update.begin(updateSize, partition))
   #define F_UpdateEnd() (mode_z ? F_Update.endgz() : F_Update.end())
   #define F_abort() if (mode_z) F_Update.abortgz(); else F_Update.abort()
   #define F_writeStream() (mode_z ? F_Update.writeGzStream(*_stream, updateSize) : F_Update.writeStream(*_stream))
@@ -100,7 +100,7 @@ extern "C" {
   #define F_Update Update
   #define F_hasZlib() false
   #define F_isZlibStream() false
-  #define F_canBegin() F_Update.begin(fwsize, partition)
+  #define F_canBegin() F_Update.begin(updateSize, partition)
   #define F_UpdateEnd() F_Update.end()
   #define F_abort() F_Update.abort()
   #define F_writeStream() F_Update.writeStream(*_stream);