view vimtutor.com @ 34454:f8fed6c8bb60 v9.1.0143

patch 9.1.0143: [security]: autocmd causes use-after-free in set_curbuf() Commit: https://github.com/vim/vim/commit/55f8bba73be5f9c3a5a4d0d6c5f56e65f2c7d3fc Author: Christian Brabandt <cb@256bit.org> Date: Wed Feb 28 23:32:00 2024 +0100 patch 9.1.0143: [security]: autocmd causes use-after-free in set_curbuf() Problem: [security]: autocmd cause use-after-free in set_curbuf() (kawarimidoll) Solution: check side-effect of BufLeave autocommand, when the number of windows changed, close windows containing buffers that will be wiped, if curbuf changed unexpectedly make sure b_nwindows is decremented otherwise it cannot be wiped set_curbuf() already makes some efforts to ensure the BufLeave autocommands do not cause issues. However there are still 2 issues that are not taken care of: 1) If a BufLeave autocommand opens a new window containing the same buffer as that is going got be closed in close_buffer() a bit later, we suddenly have another window open, containing a free'd buffer. So we must check if the number of windows changed and if it does (and the current buffer is going to be wiped (according to the 'bufhidden' setting), let's immediately close all windows containing the current buffer using close_windows() 2) If a BufLeave autocommand changes our current buffer (displays it in the current window), buf->b_nwindow will be incremented. As part of set_curbuf() we will however enter another buffer soon, which means, the newly created curbuf will have b_nwindows still have set, even so the buffer is no longer displayed in a window. This causes later problems, because it will no longer be possible to wipe such a buffer. So just before entering the final buffer, check if the curbuf changed when calling the BufLeave autocommand and if it does (and curbuf is still valid), decrement curbuf->b_nwindows. Both issues can be verified using the provided test (however the second issue only because such an impacted buffer won't be wiped, causing futher issues in later tests). fixes: #13839 closes: #14104 Signed-off-by: Christian Brabandt <cb@256bit.org>
author Christian Brabandt <cb@256bit.org>
date Wed, 28 Feb 2024 23:45:03 +0100
parents 6f55637de261
children
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$ !
$ !=====================================================================
$ !
$ !	VimTutor.com	version 29-Aug-2002
$ !
$ !	Author: Tom Wyant <Thomas.R.Wyant-III@usa.dupont.com>
$ !
$ !	This DCL command procedure executes the vimtutor command
$ !	(surprise, surprise!) which gives you a brief tutorial on the
$ !	VIM editor. Languages other than the default are supported in
$ !	the usual way, as are at least some of the command qualifiers,
$ !	though you'll need to play some fairly serious games with DCL
$ !	to specify ones that need quoting.
$ !
$ !	Copyright (c) 2002 E. I. DuPont de Nemours and Company, Inc
$ !
$ !	This program is free software; you can redistribute it and/or
$ !	modify it under the terms of the VIM license as available from
$ !	the vim 6.1 ":help license" command or (at your option) the
$ !	license from any later version of vim.
$ !
$ !	This program is distributed in the hope that it will be useful,
$ !	but WITHOUT ANY WARRANTY; without even the implied warranty of
$ !	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
$ !
$ !=====================================================================
$ !
$ !
$ !	Check for the existence of VIM, and die if it isn't there.
$ !
$	if f$search ("vim:vim.exe") .eqs. ""
$	then
$	    write sys$error "Error - Can't run tutorial. VIM not found."
$	    exit
$	endif
$ !
$ !
$ !	Pick up the argument, if any.
$ !
$	inx = 0
$ arg_loop:
$	inx = inx + 1
$	if f$type (p'inx') .nes. ""
$	then
$	    if p'inx' .nes. "" .and. f$locate ("-", p'inx') .ne. 0
$	    then
$		xx = p'inx'
$		assign/nolog "''xx'" xx
$		p'inx' = ""
$	    endif
$	    goto arg_loop
$	endif
$ !
$ !
$ !	Make sure we clean up our toys when we're through playing.
$ !
$	on error then goto exit
$ !
$ !
$ !	Create the VIM foreign command if needed
$ !
$	if f$type (vim) .eqs. "" then vim := $vim:vim
$ !
$ !
$ !	Build the name for our temp file.
$ !
$	tutfil = "sys$login:vimtutor_" + -
		f$edit (f$getjpi (0, "pid"), "trim") + "."
$	assign/nolog 'tutfil' TUTORCOPY
$ !
$ !
$ !	Copy the selected file to the temp file
$ !
$	assign/nolog/user nla0: sys$error
$	assign/nolog/user nla0: sys$output
$	vim -u "NONE" -c "so $VIMRUNTIME/tutor/tutor.vim"
$ !
$ !
$ !	Run the tutorial
$ !
$	assign/nolog/user sys$command sys$input
$	vim -u "NONE" -c "set nocp" 'p1' 'p2' 'p3' 'p4' 'p5' 'p6' 'p7' 'p8' 'tutfil'
$ !
$ !
$ !	Ditch the copy.
$ !
$ exit:
$	if f$type (tutfil) .nes. "" .and. f$search (tutfil) .nes. "" then -
$	    delete 'tutfil';*
$	if f$type (xx) .nes. "" then deassign xx
$	deassign TUTORCOPY
$	exit
$ !
$ !=====================================================================
$ !
$ !		Modification history
$ !
$ !	29-Aug-2002	T. R. Wyant
$ !		Changed license to vim.
$ !		Fix error "input is not from a terminal"
$ !		Juggle documentation (copyright and contact to front,
$ !			modification history to end).
$ !	25-Jul-2002	T. R. Wyant
$ !		Initial version