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view src/testdir/test_windows_home.vim @ 33811:06219b3bdaf3 v9.0.2121

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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 08940efa6b4e
children
line wrap: on
line source

" Test for $HOME on Windows.

source check.vim
CheckMSWindows

let s:env = {}

func s:restore_env()
  for i in keys(s:env)
    exe 'let ' . i . '=s:env["' . i . '"]'
  endfor
endfunc

func s:save_env(...)
  for i in a:000
    exe 'let s:env["' . i . '"]=' . i
  endfor
endfunc

func s:unlet_env(...)
  for i in a:000
    exe 'let ' . i . '=""'
  endfor
endfunc

func CheckHomeIsMissingFromSubprocessEnvironment()
  silent! let out = system('set')
  let env = filter(split(out, "\n"), 'v:val=~"^HOME="')
  call assert_equal(0, len(env))
endfunc

func CheckHomeIsInSubprocessEnvironment(exp)
  silent! let out = system('set')
  let env = filter(split(out, "\n"), 'v:val=~"^HOME="')
  let home = len(env) == 0 ? "" : substitute(env[0], '[^=]\+=', '', '')
  call assert_equal(a:exp, home)
endfunc

func CheckHome(exp, ...)
  call assert_equal(a:exp, $HOME)
  call assert_equal(a:exp, expand('~', ':p'))
  if !a:0
    call CheckHomeIsMissingFromSubprocessEnvironment()
  else
    call CheckHomeIsInSubprocessEnvironment(a:1)
  endif
endfunc

func Test_WindowsHome()
  command! -nargs=* SaveEnv call <SID>save_env(<f-args>)
  command! -nargs=* RestoreEnv call <SID>restore_env()
  command! -nargs=* UnletEnv call <SID>unlet_env(<f-args>)
  set noshellslash

  let save_home = $HOME
  SaveEnv $USERPROFILE $HOMEDRIVE $HOMEPATH
  try
    " Normal behavior: use $HOMEDRIVE and $HOMEPATH, ignore $USERPROFILE
    let $USERPROFILE = 'unused'
    let $HOMEDRIVE = 'C:'
    let $HOMEPATH = '\foobar'
    let $HOME = ''  " Force recomputing "homedir"
    call CheckHome('C:\foobar')

    " Same, but with $HOMEPATH not set
    UnletEnv $HOMEPATH
    let $HOME = ''  " Force recomputing "homedir"
    call CheckHome('C:\')

    " Use $USERPROFILE if $HOMEPATH and $HOMEDRIVE are empty
    UnletEnv $HOMEDRIVE $HOMEPATH
    let $USERPROFILE = 'C:\foo'
    let $HOME = ''  " Force recomputing "homedir"
    call CheckHome('C:\foo')

    " If $HOME is set the others don't matter
    let $HOME = 'C:\bar'
    let $USERPROFILE = 'unused'
    let $HOMEDRIVE = 'unused'
    let $HOMEPATH = 'unused'
    call CheckHome('C:\bar', 'C:\bar')

    " If $HOME contains %USERPROFILE% it is expanded
    let $USERPROFILE = 'C:\foo'
    let $HOME = '%USERPROFILE%\bar'
    let $HOMEDRIVE = 'unused'
    let $HOMEPATH = 'unused'
    call CheckHome('C:\foo\bar', '%USERPROFILE%\bar')

    " Invalid $HOME is kept
    let $USERPROFILE = 'C:\foo'
    let $HOME = '%USERPROFILE'
    let $HOMEDRIVE = 'unused'
    let $HOMEPATH = 'unused'
    call CheckHome('%USERPROFILE', '%USERPROFILE')

    " %USERPROFILE% not at start of $HOME is not expanded
    let $USERPROFILE = 'unused'
    let $HOME = 'C:\%USERPROFILE%'
    let $HOMEDRIVE = 'unused'
    let $HOMEPATH = 'unused'
    call CheckHome('C:\%USERPROFILE%', 'C:\%USERPROFILE%')

    if has('channel')
      RestoreEnv
      let $HOME = save_home
      let env = ''
      let job = job_start('cmd /c set', {'out_cb': {ch,x->[env,execute('let env=x')]}})
      sleep 1
      let env = filter(split(env, "\n"), 'v:val=="HOME"')
      let home = len(env) == 0 ? "" : env[0]
      call assert_equal('', home)
    endif
  finally
    RestoreEnv
    delcommand SaveEnv
    delcommand RestoreEnv
    delcommand UnletEnv
  endtry
endfunc

" vim: shiftwidth=2 sts=2 expandtab