Re: Apparent memory leak in libselinux

Re: Apparent memory leak in libselinux

[Stephen Smalley]

On Wed, 2009-12-30 at 16:32 -0800, Ed Swierk wrote:
> When I run the following on a F12 system booted with selinux=0, the
> tcmalloc heap checker complains about a leak somewhere in libselinux:
> 
> $ HEAPCHECK=normal LD_PRELOAD=/usr/lib64/libtcmalloc.so.0
> /usr/bin/python -c 'import _ssl'
> 
> Leak check _main_ detected leaks of 120 bytes in 1 objects
> The 1 largest leaks:
> Leak of 120 bytes in 1 objects allocated from:
>        @ 0x3bf9866589 _IO_getdelim
>        @ 0x3bfb40ca53 set_selinuxmnt
>        @ 0x3bfb414fe6 string_to_security_class
>        @ 0x3bfb404cdb _init
>        @ 0x7fff4bdfa8ed 0x00007fff4bdfa8ed
> 
> No leak is detected when I run this with selinux enabled. My system
> has libselinux-2.0.87-1.fc12 installed.

Likely introduced by Eric's short cut for checking /proc/filesystems and
bailing immediately in the non-selinux case.  Try this:

diff --git a/libselinux/src/init.c b/libselinux/src/init.c
index ecb3199..4d010dc 100644
--- a/libselinux/src/init.c
+++ b/libselinux/src/init.c
@@ -59,8 +59,10 @@ static void init_selinuxmnt(void)
 	}
 	fclose(fp);
 
-	if (!exists)
+	if (!exists) {
+		free(buf);
 		return;
+	}
 
 	/* At this point, the usual spot doesn't have an selinuxfs so
 	 * we look around for it */

-- 
Stephen Smalley
National Security Agency


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Re: Apparent memory leak in libselinux

[Joshua Brindle]

Ed Swierk wrote:
> On Mon, Jan 4, 2010 at 1:36 PM, Stephen Smalley<sds@tycho.nsa.gov>  wrote:
>> Likely introduced by Eric's short cut for checking /proc/filesystems and
>> bailing immediately in the non-selinux case.  Try this:
>
> There are a couple of other leakage cases to worry about. I submitted
> a patch here: http://userspace.selinuxproject.org/trac/ticket/10
>

Can you send the patch to the list please?

Guidelines on patch preparations are available at:
http://userspace.selinuxproject.org/trac/wiki/Contributing

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