api: Add global attribute imageinput:strict

src/include/OpenImageIO/imageio.h

@@ -2981,6 +2981,17 @@ OIIO_API std::string geterror(bool clear = true);
 ///   If nonzero, an `ImageBuf` that references a file but is not given an
 ///   ImageCache will read the image through the default ImageCache.
 ///
+/// - `imageinput:strict` (int: 0)
+///
+///   If zero (the default), ImageInput readers will try to be very tolerant
+///   of minor flaws or invalidity in image files being read, if possible just
+///   skipping something erroneous it encounters in the hopes that the rest of
+///   the file's data will be usable. If nonzero, anything clearly invalid in
+///   the file will be understood to be a corrupt file with unreliable data at
+///   best, and possibly malicious construction, and so will not attempt to
+///   further decode anything in the file. This may be a better choice to
+///   enable globally in an environment where security is a higher priority
+///   than being tolerant of partially broken image files.
 OIIO_API bool attribute(string_view name, TypeDesc type, const void* val);
 
 /// Shortcut attribute() for setting a single integer.

src/include/imageio_pvt.h

@@ -47,6 +47,7 @@ extern int limit_channels;
 extern int limit_imagesize_MB;
 extern int imagebuf_print_uncaught_errors;
 extern int imagebuf_use_imagecache;
+extern int imageinput_strict;
 extern atomic_ll IB_local_mem_current;
 extern atomic_ll IB_local_mem_peak;
 extern std::atomic<float> IB_total_open_time;

src/libOpenImageIO/imageio.cpp

@@ -55,6 +55,7 @@ int dds_bc5normal(0);
 int limit_channels(1024);
 int limit_imagesize_MB(std::min(32 * 1024,
                                 int(Sysutil::physical_memory() >> 20)));
+int imageinput_strict(0);
 ustring font_searchpath(Sysutil::getenv("OPENIMAGEIO_FONTS"));
 ustring plugin_searchpath(OIIO_DEFAULT_PLUGIN_SEARCHPATH);
 std::string format_list;         // comma-separated list of all formats
@@ -403,6 +404,10 @@ attribute(string_view name, TypeDesc type, const void* val)
         imagebuf_use_imagecache = *(const int*)val;
         return true;
     }
+    if (name == "imageinput:strict" && type == TypeInt) {
+        imageinput_strict = *(const int*)val;
+        return true;
+    }
     if (name == "use_tbb" && type == TypeInt) {
         oiio_use_tbb = *(const int*)val;
         return true;
@@ -578,6 +583,10 @@ getattribute(string_view name, TypeDesc type, void* val)
         *(int*)val = imagebuf_use_imagecache;
         return true;
     }
+    if (name == "imageinput:strict" && type == TypeInt) {
+        *(int*)val = imageinput_strict;
+        return true;
+    }
     if (name == "use_tbb" && type == TypeInt) {
         *(int*)val = oiio_use_tbb;
         return true;