drivers/scsi/aacraid: eliminate use after free

PATCH New [email protected] 1 participant 1 message May 24, 2010

Subsystems (2)

SCSI Aacraid SCSI RAID driver

lore

Share & tools

lore

[email protected]

author

2010-05-24 19:12 UTC #0 lore raw

PATCH 1/1 drivers/scsi/aacraid: eliminate use after free

From: Julia Lawall <[email protected]>

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 <[email protected]>

Cc James Bottomley <[email protected]>

Cc <[email protected]>

Signed-off-by Andrew Morton <[email protected]>

---

 drivers/scsi/aacraid/commctrl.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

drivers/scsi/aacraid/commctrl.c renamed from drivers/scsi/aacraid/commctrl.c~drivers-scsi-aacraid-eliminate-use-after-free +2 -2

diff -puN drivers/scsi/aacraid/commctrl.c~drivers-scsi-aacraid-eliminate-use-after-free drivers/scsi/aacraid/commctrl.c
@@ -655,9 +655,9 @@ static int aac_send_raw_srb(struct aac_d
 				/* 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;
 				}