.

GreycLab · Aug 17, 2023 · 6583d2f · 6583d2f
2 parents dedd613 + 4e74663
commit 6583d2f
Showing 1 changed file with 41 additions and 16 deletions.
diff --git a/CImg.h b/CImg.h
@@ -7385,11 +7385,18 @@ namespace cimg_library {
        \param filename Specified filename to get size from.
        \return File size or '-1' if file does not exist.
     **/
-    inline cimg_int64 fsize(const char *const filename) {
-      std::FILE *const file = cimg::std_fopen(filename,"rb");
+    inline cimg_int64 fsize(std::FILE *const file) {
       if (!file) return (cimg_int64)-1;
+      const long pos = std::ftell(file);
       std::fseek(file,0,SEEK_END);
       const cimg_int64 siz = (cimg_int64)std::ftell(file);
+      std::fseek(file,pos,SEEK_SET);
+      return siz;
+    }
+
+    inline cimg_int64 fsize(const char *const filename) {
+      std::FILE *const file = cimg::std_fopen(filename,"rb");
+      const cimg_int64 siz = fsize(file);
       cimg::fclose(file);
       return siz;
     }
@@ -54417,7 +54424,7 @@ namespace cimg_library {
                                     "load_bmp(): Specified filename is (null).",
                                     cimg_instance);
 
-      const ulongT fsiz = file?(ulongT)cimg_max_buf_size:(ulongT)cimg::fsize(filename);
+      const ulongT fsiz = (ulongT)(file?cimg::fsize(file):cimg::fsize(filename));
       std::FILE *const nfile = file?file:cimg::fopen(filename,"rb");
       CImg<ucharT> header(54);
       cimg::fread(header._data,54,nfile);
@@ -54440,32 +54447,50 @@ namespace cimg_library {
         nb_colors = header[0x2E] + (header[0x2F]<<8) + (header[0x30]<<16) + (header[0x31]<<24),
         bpp = header[0x1C] + (header[0x1D]<<8);
 
-      if (!file_size || file_size==offset) {
-        cimg::fseek(nfile,0,SEEK_END);
-        file_size = (int)cimg::ftell(nfile);
-        cimg::fseek(nfile,54,SEEK_SET);
-      }
-      if (header_size>40) cimg::fseek(nfile,header_size - 40,SEEK_CUR);
+      if ((ulongT)file_size!=fsiz)
+        throw CImgIOException(_cimg_instance
+                              "load_bmp(): Invalid file_size %d specified in filename '%s' (expected %lu).",
+                              cimg_instance,
+                              file_size,filename?filename:"(FILE*)",fsiz);
+
+      if (header_size<0 || header_size>=file_size)
+        throw CImgIOException(_cimg_instance
+                              "load_bmp(): Invalid header size %d specified in filename '%s'.",
+                              cimg_instance,
+                              header_size,filename?filename:"(FILE*)");
 
+      if (offset<0 || offset>=file_size)
+        throw CImgIOException(_cimg_instance
+                              "load_bmp(): Invalid offset %d specified in filename '%s'.",
+                              cimg_instance,
+                              offset,filename?filename:"(FILE*)");
+
+      if (header_size>40) cimg::fseek(nfile,header_size - 40,SEEK_CUR);
       const int
         dx_bytes = (bpp==1)?(dx/8 + (dx%8?1:0)):((bpp==4)?(dx/2 + (dx%2)):(int)((longT)dx*bpp/8)),
         align_bytes = (4 - dx_bytes%4)%4;
       const ulongT
         cimg_iobuffer = (ulongT)24*1024*1024,
         buf_size = (ulongT)cimg::abs(dy)*(dx_bytes + align_bytes);
 
-      if (buf_size>fsiz)
-          throw CImgIOException(_cimg_instance
-                                "load_bmp(): File size %lu for filename '%s' does not match "
-                                "encoded image dimensions (%d,%d).",
-                                cimg_instance,
-                                (long)fsiz,filename?filename:"(FILE*)",dx,dy);
+      if (buf_size>=fsiz)
+        throw CImgIOException(_cimg_instance
+                              "load_bmp(): File size %lu for filename '%s' does not match "
+                              "encoded image dimensions (%d,%d).",
+                              cimg_instance,
+                              (long)fsiz,filename?filename:"(FILE*)",dx,dy);
 
       CImg<intT> colormap;
       if (bpp<16) { if (!nb_colors) nb_colors = 1<<bpp; } else nb_colors = 0;
       if (nb_colors) { colormap.assign(nb_colors); cimg::fread(colormap._data,nb_colors,nfile); }
+
       const int xoffset = offset - 14 - header_size - 4*nb_colors;
-      if (xoffset>0) cimg::fseek(nfile,xoffset,SEEK_CUR);
+      if (xoffset<0 || xoffset>=file_size)
+        throw CImgIOException(_cimg_instance
+                              "load_bmp(): Malformed header in filename '%s'.",
+                              cimg_instance,
+                              filename?filename:"(FILE*)");
+      cimg::fseek(nfile,xoffset,SEEK_CUR);
 
       CImg<ucharT> buffer;
       if (buf_size<cimg_iobuffer) {