Patchwork [2/3] drivers/mtd/maps: Eliminate use after free

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Submitter Julia Lawall
Date April 2, 2010, 12:47 p.m.
Message ID <Pine.LNX.4.64.1004021447160.17695@ask.diku.dk>
Download mbox | patch
Permalink /patch/49292/
State New
Headers show

Comments

Julia Lawall - April 2, 2010, 12:47 p.m.
From: Julia Lawall <julia@diku.dk>

Moved the debugging message before the call to map_destroy, which frees its
argument.  The message is also slightly changed to reflect its new
position.

A simplified version of the semantic patch that finds this problem is as
follows: (http://coccinelle.lip6.fr/)

// <smpl>
@@
expression E,E2;
@@

del_mtd_device(E)
...
(
  E = E2
|
* E
)
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>

---
 drivers/mtd/maps/pcmciamtd.c        |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
Artem Bityutskiy - April 27, 2010, 7:19 a.m.
On Fri, 2010-04-02 at 14:47 +0200, Julia Lawall wrote:
> From: Julia Lawall <julia@diku.dk>
> 
> Moved the debugging message before the call to map_destroy, which frees its
> argument.  The message is also slightly changed to reflect its new
> position.
> 
> A simplified version of the semantic patch that finds this problem is as
> follows: (http://coccinelle.lip6.fr/)

Pushed to l2-mtd-2.6.git, thanks.

Patch

diff --git a/drivers/mtd/maps/pcmciamtd.c b/drivers/mtd/maps/pcmciamtd.c
index 87b2b8f..3e339de 100644
--- a/drivers/mtd/maps/pcmciamtd.c
+++ b/drivers/mtd/maps/pcmciamtd.c
@@ -689,8 +689,8 @@  static void pcmciamtd_detach(struct pcmcia_device *link)
 
 	if(dev->mtd_info) {
 		del_mtd_device(dev->mtd_info);
+		info("mtd%d: Removing", dev->mtd_info->index);
 		map_destroy(dev->mtd_info);
-		info("mtd%d: Removed", dev->mtd_info->index);
 	}
 
 	pcmciamtd_release(link);