diff --git a/libexif/exif-data.c b/libexif/exif-data.c

index 8b280d3..b495726 100644

--- a/libexif/exif-data.c

+++ b/libexif/exif-data.c

@@ -47,6 +47,8 @@

 #undef JPEG_MARKER_APP1

 #define JPEG_MARKER_APP1 0xe1

+#define CHECKOVERFLOW(offset,datasize,structsize) (( offset >= datasize) || (structsize > datasize) || (offset > datasize - structsize ))

+

 static const unsigned char ExifHeader[] = {0x45, 0x78, 0x69, 0x66, 0x00, 0x00};

 struct _ExifDataPrivate

@@ -327,7 +329,7 @@ exif_data_load_data_thumbnail (ExifData *data, const unsigned char *d,

 		exif_log (data->priv->log, EXIF_LOG_CODE_DEBUG, "ExifData", "Bogus thumbnail offset (%u).", o);

 		return;

 	}

-	if (s > ds - o) {

+	if (CHECKOVERFLOW(o,ds,s)) {

 		exif_log (data->priv->log, EXIF_LOG_CODE_DEBUG, "ExifData", "Bogus thumbnail size (%u), max would be %u.", s, ds-o);

 		return;

 	}

@@ -420,9 +422,9 @@ exif_data_load_data_content (ExifData *data, ExifIfd ifd,

 	}

 	/* Read the number of entries */

-	if ((offset + 2 < offset) || (offset + 2 < 2) || (offset + 2 > ds)) {

+	if (CHECKOVERFLOW(offset, ds, 2)) {

 		exif_log (data->priv->log, EXIF_LOG_CODE_CORRUPT_DATA, "ExifData",

-			  "Tag data past end of buffer (%u > %u)", offset+2, ds);

+			  "Tag data past end of buffer (%u+2 > %u)", offset, ds);

 		return;

 	}

 	n = exif_get_short (d + offset, data->priv->order);

@@ -431,7 +433,7 @@ exif_data_load_data_content (ExifData *data, ExifIfd ifd,

 	offset += 2;

 	/* Check if we have enough data. */

-	if (offset + 12 * n > ds) {

+	if (CHECKOVERFLOW(offset, ds, 12*n)) {

 		n = (ds - offset) / 12;

 		exif_log (data->priv->log, EXIF_LOG_CODE_DEBUG, "ExifData",

 				  "Short data; only loading %hu entries...", n);