neovim/runtime/autoload/gzip.vim
zeertzjq 7bf0963d48
vim-patch:9.0.1833: [security] runtime file fixes (#24969)
Problem:  runtime files may execute code in current dir
Solution: only execute, if not run from current directory

The perl, zig and ruby filetype plugins and the zip and gzip autoload
plugins may try to load malicious executable files from the current
working directory.  This is especially a problem on windows, where the
current directory is implicitly in your $PATH and windows may even run a
file with the extension `.bat` because of $PATHEXT.

So make sure that we are not trying to execute a file from the current
directory. If this would be the case, error out (for the zip and gzip)
plugins or silently do not run those commands (for the ftplugins).

This assumes, that only the current working directory is bad. For all
other directories, it is assumed that those directories were
intentionally set to the $PATH by the user.

816fbcc262

Co-authored-by: Christian Brabandt <cb@256bit.org>
2023-09-01 11:38:31 +08:00

227 lines
6.6 KiB
VimL

" Vim autoload file for editing compressed files.
" Maintainer: The Vim Project <https://github.com/vim/vim>
" Last Change: 2023 Aug 10
" Former Maintainer: Bram Moolenaar <Bram@vim.org>
" These functions are used by the gzip plugin.
" Function to check that executing "cmd [-f]" works.
" The result is cached in s:have_"cmd" for speed.
fun s:check(cmd)
let name = substitute(a:cmd, '\(\S*\).*', '\1', '')
if !exists("s:have_" . name)
" safety check, don't execute anything from the current directory
let f = fnamemodify(exepath(name), ":p:h") !=# getcwd()
if !f
echoerr "Warning: NOT executing " .. name .. " from current directory!"
endif
let e = executable(name)
if e < 0
let r = system(name . " --version")
let e = (r !~ "not found" && r != "")
endif
exe "let s:have_" . name . "=" . (e && f)
endif
exe "return s:have_" . name
endfun
" Set b:gzip_comp_arg to the gzip argument to be used for compression, based on
" the flags in the compressed file.
" The only compression methods that can be detected are max speed (-1) and max
" compression (-9).
fun s:set_compression(line)
" get the Compression Method
let l:cm = char2nr(a:line[2])
" if it's 8 (DEFLATE), we can check for the compression level
if l:cm == 8
" get the eXtra FLags
let l:xfl = char2nr(a:line[8])
" max compression
if l:xfl == 2
let b:gzip_comp_arg = "-9"
" min compression
elseif l:xfl == 4
let b:gzip_comp_arg = "-1"
endif
endif
endfun
" After reading compressed file: Uncompress text in buffer with "cmd"
fun gzip#read(cmd)
" don't do anything if the cmd is not supported
if !s:check(a:cmd)
return
endif
" for gzip check current compression level and set b:gzip_comp_arg.
silent! unlet b:gzip_comp_arg
if a:cmd[0] == 'g'
call s:set_compression(getline(1))
endif
" make 'patchmode' empty, we don't want a copy of the written file
let pm_save = &pm
set pm=
" remove 'a' and 'A' from 'cpo' to avoid the alternate file changes
let cpo_save = &cpo
set cpo-=a cpo-=A
" set 'modifiable'
let ma_save = &ma
setlocal ma
" set 'write'
let write_save = &write
set write
" Reset 'foldenable', otherwise line numbers get adjusted.
if has("folding")
let fen_save = &fen
setlocal nofen
endif
" when filtering the whole buffer, it will become empty
let empty = line("'[") == 1 && line("']") == line("$")
let tmp = tempname()
let tmpe = tmp . "." . expand("<afile>:e")
if exists('*fnameescape')
let tmp_esc = fnameescape(tmp)
let tmpe_esc = fnameescape(tmpe)
else
let tmp_esc = escape(tmp, ' ')
let tmpe_esc = escape(tmpe, ' ')
endif
" write the just read lines to a temp file "'[,']w tmp.gz"
execute "silent '[,']w " . tmpe_esc
" uncompress the temp file: call system("gzip -dn tmp.gz")
call system(a:cmd . " " . s:escape(tmpe))
if !filereadable(tmp)
" uncompress didn't work! Keep the compressed file then.
echoerr "Error: Could not read uncompressed file"
let ok = 0
else
let ok = 1
" delete the compressed lines; remember the line number
let l = line("'[") - 1
if exists(":lockmarks")
lockmarks '[,']d _
else
'[,']d _
endif
" read in the uncompressed lines "'[-1r tmp"
" Use ++edit if the buffer was empty, keep the 'ff' and 'fenc' options.
setlocal nobin
if exists(":lockmarks")
if empty
execute "silent lockmarks " . l . "r ++edit " . tmp_esc
else
execute "silent lockmarks " . l . "r " . tmp_esc
endif
else
execute "silent " . l . "r " . tmp_esc
endif
" if buffer became empty, delete trailing blank line
if empty
silent $delete _
1
endif
" delete the temp file and the used buffers
call delete(tmp)
silent! exe "bwipe " . tmp_esc
silent! exe "bwipe " . tmpe_esc
endif
" Store the OK flag, so that we can use it when writing.
let b:uncompressOk = ok
" Restore saved option values.
let &pm = pm_save
let &cpo = cpo_save
let &l:ma = ma_save
let &write = write_save
if has("folding")
let &l:fen = fen_save
endif
" When uncompressed the whole buffer, do autocommands
if ok && empty
if exists('*fnameescape')
let fname = fnameescape(expand("%:r"))
else
let fname = escape(expand("%:r"), " \t\n*?[{`$\\%#'\"|!<")
endif
if &verbose >= 8
execute "doau BufReadPost " . fname
else
execute "silent! doau BufReadPost " . fname
endif
endif
endfun
" After writing compressed file: Compress written file with "cmd"
fun gzip#write(cmd)
if exists('b:uncompressOk') && !b:uncompressOk
echomsg "Not compressing file because uncompress failed; reset b:uncompressOk to compress anyway"
" don't do anything if the cmd is not supported
elseif s:check(a:cmd)
" Rename the file before compressing it.
let nm = resolve(expand("<afile>"))
let nmt = s:tempname(nm)
if rename(nm, nmt) == 0
if exists("b:gzip_comp_arg")
call system(a:cmd . " " . b:gzip_comp_arg . " -- " . s:escape(nmt))
else
call system(a:cmd . " -- " . s:escape(nmt))
endif
call rename(nmt . "." . expand("<afile>:e"), nm)
endif
endif
endfun
" Before appending to compressed file: Uncompress file with "cmd"
fun gzip#appre(cmd)
" don't do anything if the cmd is not supported
if s:check(a:cmd)
let nm = expand("<afile>")
" for gzip check current compression level and set b:gzip_comp_arg.
silent! unlet b:gzip_comp_arg
if a:cmd[0] == 'g'
call s:set_compression(readfile(nm, "b", 1)[0])
endif
" Rename to a weird name to avoid the risk of overwriting another file
let nmt = expand("<afile>:p:h") . "/X~=@l9q5"
let nmte = nmt . "." . expand("<afile>:e")
if rename(nm, nmte) == 0
if &patchmode != "" && getfsize(nm . &patchmode) == -1
" Create patchmode file by creating the decompressed file new
call system(a:cmd . " -c -- " . s:escape(nmte) . " > " . s:escape(nmt))
call rename(nmte, nm . &patchmode)
else
call system(a:cmd . " -- " . s:escape(nmte))
endif
call rename(nmt, nm)
endif
endif
endfun
" find a file name for the file to be compressed. Use "name" without an
" extension if possible. Otherwise use a weird name to avoid overwriting an
" existing file.
fun s:tempname(name)
let fn = fnamemodify(a:name, ":r")
if !filereadable(fn) && !isdirectory(fn)
return fn
endif
return fnamemodify(a:name, ":p:h") . "/X~=@l9q5"
endfun
fun s:escape(name)
" shellescape() was added by patch 7.0.111
if exists("*shellescape")
return shellescape(a:name)
endif
return "'" . a:name . "'"
endfun
" vim: set sw=2 :