Mercurial > vim
view vimtutor.com @ 33811:06219b3bdaf3 v9.0.2121
patch 9.0.2121: [security]: use-after-free in ex_substitute
Commit: https://github.com/vim/vim/commit/26c11c56888d01e298cd8044caf860f3c26f57bb
Author: Christian Brabandt <cb@256bit.org>
Date: Wed Nov 22 21:26:41 2023 +0100
patch 9.0.2121: [security]: use-after-free in ex_substitute
Problem: [security]: use-after-free in ex_substitute
Solution: always allocate memory
closes: #13552
A recursive :substitute command could cause a heap-use-after free in Vim
(CVE-2023-48706).
The whole reproducible test is a bit tricky, I can only reproduce this
reliably when no previous substitution command has been used yet
(which is the reason, the test needs to run as first one in the
test_substitute.vim file) and as a combination of the `:~` command
together with a :s command that contains the special substitution atom `~\=`
which will make use of a sub-replace special atom and calls a vim script
function.
There was a comment in the existing :s code, that already makes the
`sub` variable allocate memory so that a recursive :s call won't be able
to cause any issues here, so this was known as a potential problem
already. But for the current test-case that one does not work, because
the substitution does not start with `\=` but with `~\=` (and since
there does not yet exist a previous substitution atom, Vim will simply
increment the `sub` pointer (which then was not allocated dynamically)
and later one happily use a sub-replace special expression (which could
then free the `sub` var).
The following commit fixes this, by making the sub var always using
allocated memory, which also means we need to free the pointer whenever
we leave the function. Since sub is now always an allocated variable,
we also do no longer need the sub_copy variable anymore, since this one
was used to indicated when sub pointed to allocated memory (and had
therefore to be freed on exit) and when not.
Github Security Advisory:
https://github.com/vim/vim/security/advisories/GHSA-c8qm-x72m-q53q
Signed-off-by: Christian Brabandt <cb@256bit.org>
author | Christian Brabandt <cb@256bit.org> |
---|---|
date | Wed, 22 Nov 2023 22:15:05 +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