linux-kernel - Re: [PATCH kobjects] Fix a rare memory leak in kobject_set_name

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <alpine.LFD.2.00.1003130752001.8523@localhost>
Date:	Sat, 13 Mar 2010 07:53:59 -0500 (EST)
From:	"Robert P. J. Day" <rpjday@...shcourse.ca>
To:	Philippe De Muyter <phdm@...qel.be>
cc:	gregkh@...e.de, linux-kernel@...r.kernel.org
Subject: Re: [PATCH kobjects] Fix a rare memory leak in
 kobject_set_name_vargs

On Sat, 13 Mar 2010, Philippe De Muyter wrote:

> Hello Greg,
>
> This is a possible memory leak that I discovered only by accidental code
> reading.
>
> --
>
> If kvasprintf fails in kobject_set_name_vargs, the memory used by
> the original kobj->name is leaked.  Fix that.  I also avoid useless
> memory accesses to kobj->name by using the local variables old_name
> and new_name instead.
>
> Signed-off-by: Philippe De Muyter <phdm@...qel.be>
>
> diff -r 373fdd3df333 linux-2.6.x/lib/kobject.c
> --- a/linux-2.6.x/lib/kobject.c	Wed Aug 19 23:26:44 2009 +0200
> +++ b/linux-2.6.x/lib/kobject.c	Sat Mar 13 13:35:43 2010 +0100
> @@ -216,20 +216,22 @@ int kobject_set_name_vargs(struct kobjec
>  				  va_list vargs)
>  {
>  	const char *old_name = kobj->name;
> +	char *new_name;
>  	char *s;
>
> -	if (kobj->name && !fmt)
> +	if (old_name && !fmt)
>  		return 0;
>
> -	kobj->name = kvasprintf(GFP_KERNEL, fmt, vargs);
> -	if (!kobj->name)
> +	new_name = kvasprintf(GFP_KERNEL, fmt, vargs);
> +	if (!new_name)
>  		return -ENOMEM;
>
>  	/* ewww... some of these buggers have '/' in the name ... */
> -	while ((s = strchr(kobj->name, '/')))
> +	while ((s = strchr(new_name, '/')))
>  		s[0] = '!';
>
>  	kfree(old_name);
> +	kobj->name = new_name;
>  	return 0;
>  }

  the routine kobject_set_name_vargs() is described in
Documentation/kobject.txt as "legacy cruft" to be removed at some
point, so it's not clear there's any value in "fixing" it.

rday
--

========================================================================
Robert P. J. Day                               Waterloo, Ontario, CANADA

            Linux Consulting, Training and Kernel Pedantry.

Web page:                                          http://crashcourse.ca
Twitter:                                       http://twitter.com/rpjday
========================================================================
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/