Merge pull request #27811 from Kumataro:fix27789

imgcodecs: bmp: relax decoding size limit to over 1GiB #27811

Close https://github.com/opencv/opencv/issues/27789
Close https://github.com/opencv/opencv/issues/23233

### Pull Request Readiness Checklist

See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request

- [x] I agree to contribute to the project under Apache 2 License.
- [x] To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV
- [x] The PR is proposed to the proper branch
- [x] There is a reference to the original bug report and related work
- [x] There is accuracy test, performance test and test data in opencv_extra repository, if applicable
      Patch to opencv_extra has the same branch name.
- [ ] The feature is well documented and sample code can be built with the project CMake

modules/imgcodecs/src/bitstrm.cpp

@@ -59,7 +59,17 @@ void  RBaseStream::readBlock()
         throw RBS_THROW_EOS;
     }
 
+#ifdef _WIN32
+    // See https://learn.microsoft.com/en-us/cpp/c-runtime-library/reference/fseek-fseeki64?view=msvc-170
+    // See https://en.wikipedia.org/wiki/64-bit_computing#64-bit_data_models
+    // - Windows uses LLP64 data model, sizeof long int = 32.
+    // - Linux   uses LP64  data model, sizeof long int = 64.
+    // So for Windows, we have to use _fseeki64() instead of fseek().
+    _fseeki64( m_file, m_block_pos, SEEK_SET );
+#else
     fseek( m_file, m_block_pos, SEEK_SET );
+#endif
+
     size_t readed = fread( m_start, 1, m_block_size, m_file );
     m_end = m_start + readed;
 
@@ -120,7 +130,7 @@ void  RBaseStream::release()
 }
 
 
-void  RBaseStream::setPos( int pos )
+void  RBaseStream::setPos( int64_t pos )
 {
     CV_Assert(isOpened() && pos >= 0);
 
@@ -132,7 +142,7 @@ void  RBaseStream::setPos( int pos )
     }
 
     int offset = pos % m_block_size;
-    int old_block_pos = m_block_pos;
+    int64_t old_block_pos = m_block_pos;
     m_block_pos = pos - offset;
     m_current = m_start + offset;
     if (old_block_pos != m_block_pos)
@@ -140,16 +150,16 @@ void  RBaseStream::setPos( int pos )
 }
 
 
-int  RBaseStream::getPos()
+int64_t RBaseStream::getPos()
 {
     CV_Assert(isOpened());
-    int pos = validateToInt((m_current - m_start) + m_block_pos);
+    int64_t pos = validateToInt64((m_current - m_start) + m_block_pos);
     CV_Assert(pos >= m_block_pos); // overflow check
     CV_Assert(pos >= 0); // overflow check
     return pos;
 }
 
-void  RBaseStream::skip( int bytes )
+void  RBaseStream::skip( int64_t bytes )
 {
     CV_Assert(bytes >= 0);
     uchar* old = m_current;

modules/imgcodecs/src/bitstrm.hpp

@@ -45,9 +45,9 @@ public:
     virtual bool  open( const Mat& buf );
     virtual void  close();
     bool          isOpened();
-    void          setPos( int pos );
-    int           getPos();
-    void          skip( int bytes );
+    void          setPos( int64_t pos );
+    int64_t       getPos();
+    void          skip( int64_t bytes );
 
 protected:
 
@@ -57,7 +57,7 @@ protected:
     uchar*  m_current;
     FILE*   m_file;
     int     m_block_size;
-    int     m_block_pos;
+    int64_t m_block_pos;
     bool    m_is_opened;
 
     virtual void  readBlock();

modules/imgcodecs/src/grfmt_bmp.cpp

@@ -237,9 +237,6 @@ bool  BmpDecoder::readData( Mat& img )
     int  nch = color ? 3 : 1;
     int  y, width3 = m_width*nch;
 
-    // FIXIT: use safe pointer arithmetic (avoid 'int'), use size_t, intptr_t, etc
-    CV_Assert(((uint64)m_height * m_width * nch < (CV_BIG_UINT(1) << 30)) && "BMP reader implementation doesn't support large images >= 1Gb");
-
     if( m_offset < 0 || !m_strm.isOpened())
         return false;
 

modules/imgcodecs/src/grfmt_bmp.hpp

@@ -87,7 +87,7 @@ protected:
     PaletteEntry    m_palette[256];
     Origin          m_origin;
     int             m_bpp;
-    int             m_offset;
+    int64_t         m_offset;
     BmpCompression  m_rle_code;
     uint            m_rgba_mask[4];
     int             m_rgba_bit_offset[4];

modules/imgcodecs/src/grfmt_pam.hpp

@@ -78,8 +78,8 @@ public:
 protected:
 
     RLByteStream    m_strm;
-    int m_maxval, m_channels, m_sampledepth, m_offset,
-        selected_fmt;
+    int64_t m_offset;
+    int m_maxval, m_channels, m_sampledepth, selected_fmt;
     bool bit_mode;
 };
 

modules/imgcodecs/src/grfmt_pxm.hpp

@@ -79,7 +79,7 @@ protected:
     RLByteStream    m_strm;
     PaletteEntry    m_palette[256];
     int             m_bpp;
-    int             m_offset;
+    int64_t         m_offset;
     bool            m_binary;
     int             m_maxval;
 };

modules/imgcodecs/src/grfmt_sunras.cpp

@@ -94,7 +94,7 @@ bool  SunRasterDecoder::readHeader()
                     m_type = IsColorPalette( m_palette, m_bpp ) ? CV_8UC3 : CV_8UC1;
                     m_offset = m_strm.getPos();
 
-                    CV_Assert(m_offset == 32 + m_maplength);
+                    CV_Assert(m_offset == static_cast<int64_t>(32 + m_maplength));
                     result = true;
                 }
             }
@@ -107,7 +107,7 @@ bool  SunRasterDecoder::readHeader()
 
                 m_offset = m_strm.getPos();
 
-                CV_Assert(m_offset == 32 + m_maplength);
+                CV_Assert(m_offset == static_cast<int64_t>(32 + m_maplength));
                 result = true;
             }
         }

modules/imgcodecs/src/grfmt_sunras.hpp

@@ -84,7 +84,7 @@ protected:
     RMByteStream    m_strm;
     PaletteEntry    m_palette[256];
     int             m_bpp;
-    int             m_offset;
+    int64_t         m_offset;
     SunRasType      m_encoding;
     SunRasMapType   m_maptype;
     int             m_maplength;

modules/imgcodecs/src/utils.cpp

@@ -51,6 +51,13 @@ int validateToInt(size_t sz)
     return valueInt;
 }
 
+int64_t validateToInt64(size_t sz)
+{
+    int64_t valueInt = static_cast<int64_t>(sz);
+    CV_Assert((size_t)valueInt == sz);
+    return valueInt;
+}
+
 #define  SCALE  14
 #define  cR  (int)(0.299*(1 << SCALE) + 0.5)
 #define  cG  (int)(0.587*(1 << SCALE) + 0.5)

modules/imgcodecs/src/utils.hpp

@@ -45,6 +45,7 @@
 namespace cv {
 
 int validateToInt(size_t step);
+int64_t validateToInt64(size_t step);
 
 template <typename _Tp> static inline
 size_t safeCastToSizeT(const _Tp v_origin, const char* msg)