handle Photoshop chunks which can't be processed

python-pillow · Jan 19, 2020 · f55eb73 · f55eb73
1 parent 3841c96
commit f55eb73
Showing 1 changed file with 33 additions and 31 deletions.
diff --git a/src/PIL/JpegImagePlugin.py b/src/PIL/JpegImagePlugin.py
@@ -101,37 +101,39 @@ def APP(self, marker):
         # markers appear in the correct sequence.
         self.icclist.append(s)
     elif marker == 0xFFED and s[:14] == b"Photoshop 3.0\x00":
-        # parse the image resource block
-        offset = 14
-        photoshop = {}
-        while s[offset : offset + 4] == b"8BIM":
-            offset += 4
-            # resource code
-            try:
-                code = i16(s, offset)
-            except struct.error:
-                break
-            offset += 2
-            # resource name (usually empty)
-            name_len = i8(s[offset])
-            # name = s[offset+1:offset+1+name_len]
-            offset += 1 + name_len
-            offset += offset & 1  # align
-            # resource data block
-            size = i32(s, offset)
-            offset += 4
-            data = s[offset : offset + size]
-            if code == 0x03ED:  # ResolutionInfo
-                data = {
-                    "XResolution": i32(data[:4]) / 65536,
-                    "DisplayedUnitsX": i16(data[4:8]),
-                    "YResolution": i32(data[8:12]) / 65536,
-                    "DisplayedUnitsY": i16(data[12:]),
-                }
-            photoshop[code] = data
-            offset += size
-            offset += offset & 1  # align
-        self.info["photoshop"] = photoshop
+        # Process this marker only if previous were empty
+        if not self.info.get("photoshop"):
+            # parse the image resource block
+            offset = 14
+            photoshop = {}
+            while s[offset : offset + 4] == b"8BIM":
+                try:
+                    offset += 4
+                    # resource code
+                    code = i16(s, offset)
+                    offset += 2
+                    # resource name (usually empty)
+                    name_len = i8(s[offset])
+                    # name = s[offset+1:offset+1+name_len]
+                    offset += 1 + name_len
+                    offset += offset & 1  # align
+                    # resource data block
+                    size = i32(s, offset)
+                    offset += 4
+                    data = s[offset : offset + size]
+                    if code == 0x03ED:  # ResolutionInfo
+                        data = {
+                            "XResolution": i32(data[:4]) / 65536,
+                            "DisplayedUnitsX": i16(data[4:8]),
+                            "YResolution": i32(data[8:12]) / 65536,
+                            "DisplayedUnitsY": i16(data[12:]),
+                        }
+                    photoshop[code] = data
+                    offset += size
+                    offset += offset & 1  # align
+                except struct.error:
+                    break  # no sufficient data
+            self.info["photoshop"] = photoshop
 
     elif marker == 0xFFEE and s[:5] == b"Adobe":
         self.info["adobe"] = i16(s, 5)