5ac04f2f02
Upstream commit:
Date: Wed, 8 Sep 2010 20:07:26 +0800
[EXPAND] Fix ifsfirst/ifslastp leak
As it stands expandarg may return with a non-NULL ifslastp which
then confuses any subsequent ifsbreakup user that doesn't clear
it directly.
What's worse, if we get interrupted before we hit ifsfree in
expandarg we will leak memory.
This patch fixes this by always calling ifsfree in expandarg
thus ensuring that ifslastp is always NULL on the normal path.
It also adds an ifsfree call to the RESET path to ensure that
memory isn't leaked.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Fallout 1:
Date: Mon, 18 Oct 2010 10:55:42 +0800
[EXPAND] Fix ifsfirst/ifslastp leak in casematch
The commit f42e443bb511ed3224f09b4fcf0772438ebdbbfa
[EXPAND] Fix ifsfirst/ifslastp leak
revealed yet another ifsfirst/ifslastp leak in casematch.
Previously it was hidden because ifsfirst/ifslastp was cleared
unconditionally on entry (which caused the leakage of those
entries).
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Fallout 2:
Date: Sun, 28 Nov 2010 21:09:51 +0800
[EXPAND] Free IFS state in evalbackcmd
On Sun, Nov 07, 2010 at 04:04:20PM -0600, Jonathan Nieder wrote:
> Herbert Xu wrote:
> > commit f42e443bb511ed3224f09b4fcf0772438ebdbbfa
> > Author: Herbert Xu <herbert@gondor.apana.org.au>
> > Date: Wed Sep 8 20:07:26 2010 +0800
> >
> > [EXPAND] Fix ifsfirst/ifslastp leak
>
> Another puzzle bisecting to f42e443bb. This one comes from the
> grub-mkconfig script:
>
> $ sh -c 'datadir=/usr/share; pkgdatadir=${datadir}/`cat`' 2>&1 | cat -A
> cat: M-^\^M^F^HM-4^M^F^HM-(^M^F^H: No such file or directory$
> cat: M-(^M^F^H: No such file or directory$
>
> Still reproducible with 016b529. I'll try to find time to look into
> it, but thought you might like to know nevertheless.
This is the symptom of another leak. In this case evalbackcmd
occurs in the middle of an expansion (as it should) but the forked
child never clears the previous IFS state.
This patch adds the missing ifsfree call.
This wasn't as much of a problem as the previously discovered leaks
since all it means is that the child gets to carry around the parent's
expansion state and the child is usually short-lived.
Reported-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Fallout 3:
Date: Tue, 15 Mar 2011 16:01:34 +0800
[EXPAND] Free IFS state after here document expansion
Here's another bug bisecting to f42e443bb ([EXPAND] Fix
ifsfirst/ifslastp leak, 2010-09-08). It was found with the following
test case, based on the configure script for Tracker:
dash -x -c '
<<-_ACEOF
$@
_ACEOF
exec
' - abcdefgh
+
+ exec ?a
exec: 1: : Permission denied
The missing ifsfree call is in expandarg when it returns to openhere
during here document expansion.
Reported-by: Aurelien Jarno <aurel32@debian.org>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
function old new delta
ifsfree - 66 +66
ash_main 1490 1495 +5
argstr 1154 1159 +5
evalcase 275 270 -5
expandarg 972 888 -84
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 2/2 up/down: 76/-89) Total: -13 bytes
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
http://www.opengroup.org/onlinepubs/9699919799/ Open Group Base Specifications Issue 7 http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap01.html Shell & Utilities It says that any of the standard utilities may be implemented as a regular shell built-in. It gives a list of utilities which are usually implemented that way (and some of them can only be implemented as built-ins, like "alias"): alias bg cd command false fc fg getopts jobs kill newgrp pwd read true umask unalias wait http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html Shell Command Language It says that shell must implement special built-ins. Special built-ins differ from regular ones by the fact that variable assignments done on special builtin are *PRESERVED*. That is, VAR=VAL special_builtin; echo $VAR should print VAL. (Another distinction is that an error in special built-in should abort the shell, but this is not such a critical difference, and moreover, at least bash's "set" does not follow this rule, which is even codified in autoconf configure logic now...) List of special builtins: . file : [argument...] break [n] continue [n] eval [argument...] exec [command [argument...]] exit [n] export name[=word]... export -p readonly name[=word]... readonly -p return [n] set [-abCefhmnuvx] [-o option] [argument...] set [+abCefhmnuvx] [+o option] [argument...] set -- [argument...] set -o set +o shift [n] times trap n [condition...] trap [action condition...] unset [-fv] name... In practice, no one uses this obscure feature - none of these builtins gives any special reasons to play such dirty tricks. However. This section also says that *function invocation* should act similar to special built-in. That is, variable assignments done on function invocation should be preserved after function invocation. This is significant: it is not unthinkable to want to run a function with some variables set to special values. But because of the above, it does not work: variable will "leak" out of the function.