[2.2.x] Fixed CVE-2019-14235 -- Fixed potential memory exhaustion in django.utils.encoding.uri_to_iri().

Thanks to Guido Vranken for initial report.

1 files changed, 10 insertions, 7 deletions

diff --git a/django/utils/encoding.py b/django/utils/encoding.py
index 1a1a6d06b1..98da64730d 100644
--- a/django/utils/encoding.py
+++ b/django/utils/encoding.py
@@ -225,13 +225,16 @@ def repercent_broken_unicode(path):
     repercent-encode any octet produced that is not part of a strictly legal
     UTF-8 octet sequence.
     """
-    try:
-        path.decode()
-    except UnicodeDecodeError as e:
-        repercent = quote(path[e.start:e.end], safe=b"/#%[]=:;$&()+,!?*@'~")
-        path = repercent_broken_unicode(
-            path[:e.start] + force_bytes(repercent) + path[e.end:])
-    return path
+    while True:
+        try:
+            path.decode()
+        except UnicodeDecodeError as e:
+            # CVE-2019-14235: A recursion shouldn't be used since the exception
+            # handling uses massive amounts of memory
+            repercent = quote(path[e.start:e.end], safe=b"/#%[]=:;$&()+,!?*@'~")
+            path = path[:e.start] + force_bytes(repercent) + path[e.end:]
+        else:
+            return path
 
 
 def filepath_to_uri(path):