From: Julia Lawall <julia@diku.dk>
Date: Sat, 15 May 2010 09:46:12 +0000 (+0200)
Subject: SCSI: aacraid: Eliminate use after free
X-Git-Tag: firefly_0821_release~10186^2~1391
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=de40885b3c038fb7934f798d3cab823cd5985955;p=firefly-linux-kernel-4.4.55.git

SCSI: aacraid: Eliminate use after free

commit 8a52da632ceb9d8b776494563df579e87b7b586b upstream.

The debugging code using the freed structure is moved before the kfree.

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

// <smpl>
@free@
expression E;
position p;
@@
kfree@p(E)

@@
expression free.E, subE<=free.E, E1;
position free.p;
@@

  kfree@p(E)
  ...
(
  subE = E1
|
* E
)
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
---

diff --git a/drivers/scsi/aacraid/commctrl.c b/drivers/scsi/aacraid/commctrl.c
index 0391d759dfdb..a5b8e7b92701 100644
--- a/drivers/scsi/aacraid/commctrl.c
+++ b/drivers/scsi/aacraid/commctrl.c
@@ -655,9 +655,9 @@ static int aac_send_raw_srb(struct aac_dev* dev, void __user * arg)
 				/* Does this really need to be GFP_DMA? */
 				p = kmalloc(usg->sg[i].count,GFP_KERNEL|__GFP_DMA);
 				if(!p) {
-					kfree (usg);
-					dprintk((KERN_DEBUG"aacraid: Could not allocate SG buffer - size = %d buffer number %d of %d\n",
+					dprintk((KERN_DEBUG "aacraid: Could not allocate SG buffer - size = %d buffer number %d of %d\n",
 					  usg->sg[i].count,i,usg->count));
+					kfree(usg);
 					rcode = -ENOMEM;
 					goto cleanup;
 				}