[PATCH dash] [EXPAND] Free IFS state after here document expansion

[PATCH dash] [EXPAND] Free IFS state after here document expansion

[Jonathan Nieder]

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>
---
Hi,

Aurelien Jarno wrote[1]:

>   https://buildd.debian.org/fetch.cgi?pkg=tracker&arch=amd64&ver=0.10.3-1&stamp=1299968124&file=log&as=raw
[...]
> |  57145 dash     CALL  execve(0x806bf64,0x806ba64,0x806bef4)
> |  57145 dash     NAMI  "/usr/local/bincd$e,f4g<hDnLoTpu"

This patch seems to fix it.  Thoughts?

[1] http://bugs.debian.org/618023

 src/expand.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/src/expand.c b/src/expand.c
index 7a9b157..eac6c6d 100644
--- a/src/expand.c
+++ b/src/expand.c
@@ -194,6 +194,7 @@ expandarg(union node *arg, struct arglist *arglist, int flag)
 	p = _STPUTC('\0', expdest);
 	expdest = p - 1;
 	if (arglist == NULL) {
+		ifsfree();
 		return;			/* here document expanded */
 	}
 	p = grabstackstr(p);
-- 
1.7.4.1

Re: [PATCH dash] [EXPAND] Free IFS state after here document expansion

[Herbert Xu]

On Sun, Mar 13, 2011 at 01:48:58PM -0500, Jonathan Nieder wrote:
> 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>

Applied with minor rearrangement.  Thanks!
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
--
commit a58d301405d96fb8ff87cffa3cabe3b110214a31
Author: Jonathan Nieder <jrnieder@gmail.com>
Date:   Tue Mar 15 16:01:34 2011 +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>

diff --git a/ChangeLog b/ChangeLog
index 44e5bdf..5163479 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2011-03-15  Jonathan Nieder <jrnieder@gmail.com>
+
+	* Free IFS state after here document expansion.
+
 2011-03-15  Harald van Dijk <harald@gigawatt.nl>
 
 	* Let funcnode refer to a function definition, not its first command.
diff --git a/src/expand.c b/src/expand.c
index f155ea0..ce60fe9 100644
--- a/src/expand.c
+++ b/src/expand.c
@@ -194,7 +194,8 @@ expandarg(union node *arg, struct arglist *arglist, int flag)
 	p = _STPUTC('\0', expdest);
 	expdest = p - 1;
 	if (arglist == NULL) {
-		return;			/* here document expanded */
+		/* here document expanded */
+		goto out;
 	}
 	p = grabstackstr(p);
 	exparg.lastp = &exparg.list;
@@ -212,12 +213,14 @@ expandarg(union node *arg, struct arglist *arglist, int flag)
 		*exparg.lastp = sp;
 		exparg.lastp = &sp->next;
 	}
-	ifsfree();
 	*exparg.lastp = NULL;
 	if (exparg.list) {
 		*arglist->lastp = exparg.list;
 		arglist->lastp = exparg.lastp;
 	}
+
+out:
+	ifsfree();
 }