releases/2.6.32.17/scsi-aacraid-eliminate-use-after-free.patch

   1 From 8a52da632ceb9d8b776494563df579e87b7b586b Mon Sep 17 00:00:00 2001
   2 From: Julia Lawall <julia@diku.dk>
   3 Date: Sat, 15 May 2010 11:46:12 +0200
   4 Subject: SCSI: aacraid: Eliminate use after free
   5
   6 From: Julia Lawall <julia@diku.dk>
   7
   8 commit 8a52da632ceb9d8b776494563df579e87b7b586b upstream.
   9
  10 The debugging code using the freed structure is moved before the kfree.
  11
  12 A simplified version of the semantic match that finds this problem is as
  13 follows: (http://coccinelle.lip6.fr/)
  14
  15 // <smpl>
  16 @free@
  17 expression E;
  18 position p;
  19 @@
  20 kfree@p(E)
  21
  22 @@
  23 expression free.E, subE<=free.E, E1;
  24 position free.p;
  25 @@
  26
  27   kfree@p(E)
  28   ...
  29 (
  30   subE = E1
  31 |
  32 * E
  33 )
  34 // </smpl>
  35
  36 Signed-off-by: Julia Lawall <julia@diku.dk>
  37 Signed-off-by: James Bottomley <James.Bottomley@suse.de>
  38
  39 ---
  40  drivers/scsi/aacraid/commctrl.c |    4 ++--
  41  1 file changed, 2 insertions(+), 2 deletions(-)
  42
  43 --- a/drivers/scsi/aacraid/commctrl.c
  44 +++ b/drivers/scsi/aacraid/commctrl.c
  45 @@ -655,9 +655,9 @@ static int aac_send_raw_srb(struct aac_d
  46                                 /* Does this really need to be GFP_DMA? */
  47                                 p = kmalloc(usg->sg[i].count,GFP_KERNEL|__GFP_DMA);
  48                                 if(!p) {
  49 -                                       kfree (usg);
  50 -                                       dprintk((KERN_DEBUG"aacraid: Could not allocate SG buffer - size = %d buffer number %d of %d\n",
  51 +                                       dprintk((KERN_DEBUG "aacraid: Could not allocate SG buffer - size = %d buffer number %d of %d\n",
  52                                           usg->sg[i].count,i,usg->count));
  53 +                                       kfree(usg);
  54                                         rcode = -ENOMEM;
  55                                         goto cleanup;
  56                                 }