From 169315d33d6bba6907346cde3628ea6fa459ed33 Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Sat, 4 Nov 2023 07:23:59 +0530
Subject: [PATCH] Improve paste sanitization

Replace C0 chars with their graphical equivalents and \n with \eE
which has the same visual effect. C1 chars are replaced by reverse
question mark.
---
 kitty/utils.py  |  2 +-
 kitty/window.py | 20 +++++++++++++++++---
 2 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/kitty/utils.py b/kitty/utils.py
index dbd4444b3..2c0127afd 100644
--- a/kitty/utils.py
+++ b/kitty/utils.py
@@ -1022,7 +1022,7 @@ def reload_conf_in_all_kitties() -> None:
 
 @run_once
 def control_codes_pat() -> 'Pattern[str]':
-    return re.compile('[\x00-\x09\x0b-\x1f\x7f\x80-\x9f]')
+    return re.compile('[\x00-\x09\x0b-\x1f\x7f-\x9f]')
 
 
 def sanitize_control_codes(text: str, replace_with: str = '') -> str:
diff --git a/kitty/window.py b/kitty/window.py
index 1029f8ead..f8747e9d0 100644
--- a/kitty/window.py
+++ b/kitty/window.py
@@ -479,6 +479,18 @@ class GlobalWatchers:
 global_watchers = GlobalWatchers()
 
 
+def replace_control_codes(text: str) -> str:
+    # Replace all control codes other than tab, newline and space with their graphical counterparts
+    def sub(m: re.Match[str]) -> str:
+        c = ord(m.group())
+        if c < 0x20:
+            return chr(0x2400 + c)
+        if c == 0x7f:
+            return '\u2421'
+        return '\u2426'
+    return re.sub(r'[\0-\x08\x0b-\x19\x7f-\x9f]', sub, text)
+
+
 class Window:
 
     window_custom_type: str = ''
@@ -1499,12 +1511,14 @@ class Window:
                     text = shlex.quote(text)
         btext = text.encode('utf-8')
         if 'confirm' in opts.paste_actions:
-            sanitized = sanitize_control_codes(text)
+            sanitized = replace_control_codes(text)
             if not self.screen.in_bracketed_paste_mode:
                 # \n is converted to \r and \r is interpreted as the enter key
                 # by legacy programs that dont support the full kitty keyboard protocol,
-                # which in the case of shells can lead to command execution
-                sanitized = re.sub(r'[\r\n]', ' ', sanitized)
+                # which in the case of shells can lead to command execution.
+                # \eE has the same visual effect as \r\n but without the
+                # command execution risk.
+                sanitized = sanitized.replace('\n', '\x1bE')
             if sanitized != text:
                 msg = _('The text to be pasted contains terminal control codes.\n\nIf the terminal program you are pasting into does not properly'
                         ' sanitize pasted text, this can lead to \x1b[31mcode execution vulnerabilities\x1b[39m.\n\nHow would you like to proceed?')