tor

commit beedf5fd81c25e67655432e009b047252cd0a970
parent c1be0cfdb45d702afa3c1883a5e436cef8115fcd
Author: teor <teor2345@gmail.com>
Date:   Sun, 24 Dec 2017 11:24:29 +1100

Remove commas and equals signs from external string inputs to the fallback list

This makes sure that list parsers only see one comma per fallback entry,
and only see one equals sign per field.

Implements ticket 24726.

Diffstat:
A
changes/ticket24726
 | 
4
++++
M
scripts/maint/updateFallbackDirs.py
 | 
8
++++++++

2 files changed, 12 insertions(+), 0 deletions(-)
diff --git a/changes/ticket24726 b/changes/ticket24726
@@ -0,0 +1,4 @@
+  o Minor features (fallback directory mirrors):
+    - Remove commas and equals signs from external string inputs to the
+      fallback list. This avoids format confusion attacks.
+      Implements ticket 24726.
diff --git a/scripts/maint/updateFallbackDirs.py b/scripts/maint/updateFallbackDirs.py
@@ -284,6 +284,10 @@ def cleanse_c_multiline_comment(raw_string):
   bad_char_list = '*/'
   # Prevent a malicious string from using C nulls
   bad_char_list += '\0'
+  # Avoid confusing parsers by making sure there is only one comma per fallback
+  bad_char_list += ','
+  # Avoid confusing parsers by making sure there is only one equals per field
+  bad_char_list += '='
   # Be safer by removing bad characters entirely
   cleansed_string = remove_bad_chars(cleansed_string, bad_char_list)
   # Some compilers may further process the content of comments
@@ -304,6 +308,10 @@ def cleanse_c_string(raw_string):
   bad_char_list += '\\'
   # Prevent a malicious string from using C nulls
   bad_char_list += '\0'
+  # Avoid confusing parsers by making sure there is only one comma per fallback
+  bad_char_list += ','
+  # Avoid confusing parsers by making sure there is only one equals per field
+  bad_char_list += '='
   # Be safer by removing bad characters entirely
   cleansed_string = remove_bad_chars(cleansed_string, bad_char_list)
   # Some compilers may further process the content of strings