Use exiftool to strip image EXIF data (preserving orientation)

README.rst

@@ -36,6 +36,15 @@ the following:
 * ``ffmpegthumbnailer`` executable in ``$PATH``
 
 
+EXIF Stripping
+--------------
+
+When ``STRIP_IMAGE_EXIF`` is enabled, all images uploaded will be
+processed through exiftool to strip all EXIF data except the orientation
+tag.
+Requires the ``exiftool`` script in ``$PATH``.
+
+
 INSTALL
 -------
 ::

fhost.py

@@ -68,6 +68,11 @@ app.config["FHOST_UPLOAD_BLACKLIST"] = "tornodes.txt"
 app.config["NSFW_DETECT"] = False
 app.config["NSFW_THRESHOLD"] = 0.608
 
+app.config["STRIP_IMAGE_EXIF"] = True
+
+if app.config["STRIP_IMAGE_EXIF"]:
+    import subprocess
+
 if app.config["NSFW_DETECT"]:
     from nsfw_detect import NSFWDetector
     nsfw = NSFWDetector()
@@ -185,12 +190,7 @@ def in_upload_bl(addr):
 
     return False
 
-def store_file(f, addr):
-    if in_upload_bl(addr):
-        return "Your host is blocked from uploading files.\n", 451
-
-    data = f.stream.read()
-    digest = sha256(data).hexdigest()
+def check_existing(digest, data, addr):
     existing = File.query.filter_by(sha256=digest).first()
 
     if existing:
@@ -212,7 +212,20 @@ def store_file(f, addr):
         db.session.commit()
 
         return existing.geturl()
-    else:
+
+    return None
+
+def store_file(f, addr):
+    if in_upload_bl(addr):
+        return "Your host is blocked from uploading files.\n", 451
+
+    data = f.stream.read()
+    digest = sha256(data).hexdigest()
+
+    exists = check_existing(digest, data, addr)
+    if exists != None:
+        return exists
+
     guessmime = mimedetect.from_buffer(data)
 
     if not f.content_type or not "/" in f.content_type or f.content_type == "application/octet-stream":
@@ -241,6 +254,21 @@ def store_file(f, addr):
     if not ext:
         ext = ".bin"
 
+    if app.config["STRIP_IMAGE_EXIF"] and mime.startswith("image/"):
+        p = subprocess.Popen(["exiftool",
+            "-stay_open", "true",
+            "-all=",
+            "-tagsfromfile", "@",
+            "-Orientation",
+            "-" ], stdout = subprocess.PIPE, stdin = subprocess.PIPE)
+        p.stdin.write(data)
+        p.stdin.close()
+        data = p.stdout.read()
+        digest = sha256(data).hexdigest()
+        exists = check_existing(digest, data, addr)
+        if exists != None:
+            return exists
+
     spath = getpath(digest)
 
     with open(spath, "wb") as of: