[PATCH] Memory corruption in block2mtd.c

[PATCH] Memory corruption in block2mtd.c

[Ingo van Lil]

Hello everybody,

the block2mtd driver (drivers/mtd/devices/block2mtd.c) will kfree an
on-stack pointer when handling an invalid argument line (e.g.
block2mtd=/dev/loop0,xxx).

The kfree was added some time ago when "name" was dynamically
allocated.

Cheers,
Ingo

Signed-off-by: Ingo van Lil <inguin@gmx.de>
---

--- linux-2.6.23.1/drivers/mtd/devices/block2mtd.c.orig	2008-03-20 15:13:49.000000000 +0100
+++ linux-2.6.23.1/drivers/mtd/devices/block2mtd.c	2008-03-20 15:14:09.000000000 +0100
@@ -408,7 +408,6 @@
  	if (token[1]) {
  		ret = parse_num(&erase_size, token[1]);
  		if (ret) {
-			kfree(name);
  			parse_err("illegal erase size");
  		}
  	}

Re: [PATCH] Memory corruption in block2mtd.c

[Jörn Engel]

On Thu, 20 March 2008 15:36:48 +0100, Ingo van Lil wrote:
> 
> the block2mtd driver (drivers/mtd/devices/block2mtd.c) will kfree an
> on-stack pointer when handling an invalid argument line (e.g.
> block2mtd=/dev/loop0,xxx).
> 
> The kfree was added some time ago when "name" was dynamically
> allocated.

Good catch.

> Signed-off-by: Ingo van Lil <inguin@gmx.de>
Acked-by: Joern Engel <joern@lazybastard.org>

> ---
> 
> --- linux-2.6.23.1/drivers/mtd/devices/block2mtd.c.orig	2008-03-20 
> 15:13:49.000000000 +0100
> +++ linux-2.6.23.1/drivers/mtd/devices/block2mtd.c	2008-03-20 
> 15:14:09.000000000 +0100
> @@ -408,7 +408,6 @@
>  	if (token[1]) {
>  		ret = parse_num(&erase_size, token[1]);
>  		if (ret) {
> -			kfree(name);
>  			parse_err("illegal erase size");
>  		}
>  	}
> --
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Jörn

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