From: Mattias Engdegård <mattiase@acm.org>
Date: Fri, 13 Mar 2020 18:51:02 +0000 (+0100)
Subject: Avoid regexp stack overflow in GDB string matching (bug#22149)
X-Git-Tag: emacs-28.0.90~7761
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=7195ea7532f4b2e05f168da823d9aed2401267cf;p=emacs.git

Avoid regexp stack overflow in GDB string matching (bug#22149)

* lisp/progmodes/gdb-mi.el (gdb--string-regexp):
Swap the or-clauses so that the rarely matching one comes first.
This avoids a build-up of backtrack points on the regexp stack.
---

diff --git a/lisp/progmodes/gdb-mi.el b/lisp/progmodes/gdb-mi.el
index da5a2a503a6..c2622327967 100644
--- a/lisp/progmodes/gdb-mi.el
+++ b/lisp/progmodes/gdb-mi.el
@@ -1046,7 +1046,10 @@ no input, and GDB is waiting for input."
 
 (declare-function tooltip-show "tooltip" (text &optional use-echo-area))
 
-(defconst gdb--string-regexp "\"\\(?:[^\\\"]\\|\\\\.\\)*\"")
+(defconst gdb--string-regexp (rx "\""
+                                 (* (or (seq "\\" nonl)
+                                        (not (any "\"\\"))))
+                                 "\""))
 
 (defun gdb-tooltip-print (expr)
   (with-current-buffer (gdb-get-buffer 'gdb-partial-output-buffer)