queue-4.4/s390-qeth-fix-use-after-free-in-error-path.patch

   1 From 7a52d6ee03c768885b211035c04a1de160575705 Mon Sep 17 00:00:00 2001
   2 From: Julian Wiedmann <jwi@linux.ibm.com>
   3 Date: Mon, 4 Feb 2019 17:40:07 +0100
   4 Subject: s390/qeth: fix use-after-free in error path
   5
   6 [ Upstream commit afa0c5904ba16d59b0454f7ee4c807dae350f432 ]
   7
   8 The error path in qeth_alloc_qdio_buffers() that takes care of
   9 cleaning up the Output Queues is buggy. It first frees the queue, but
  10 then calls qeth_clear_outq_buffers() with that very queue struct.
  11
  12 Make the call to qeth_clear_outq_buffers() part of the free action
  13 (in the correct order), and while at it fix the naming of the helper.
  14
  15 Fixes: 0da9581ddb0f ("qeth: exploit asynchronous delivery of storage blocks")
  16 Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
  17 Reviewed-by: Alexandra Winter <wintera@linux.ibm.com>
  18 Signed-off-by: David S. Miller <davem@davemloft.net>
  19 Signed-off-by: Sasha Levin <sashal@kernel.org>
  20 ---
  21  drivers/s390/net/qeth_core_main.c | 15 ++++++---------
  22  1 file changed, 6 insertions(+), 9 deletions(-)
  23
  24 diff --git a/drivers/s390/net/qeth_core_main.c b/drivers/s390/net/qeth_core_main.c
  25 index 533bd2467910..b40604d0126f 100644
  26 --- a/drivers/s390/net/qeth_core_main.c
  27 +++ b/drivers/s390/net/qeth_core_main.c
  28 @@ -2452,11 +2452,12 @@ static int qeth_init_qdio_out_buf(struct qeth_qdio_out_q *q, int bidx)
  29         return rc;
  30  }
  31
  32 -static void qeth_free_qdio_out_buf(struct qeth_qdio_out_q *q)
  33 +static void qeth_free_output_queue(struct qeth_qdio_out_q *q)
  34  {
  35         if (!q)
  36                 return;
  37
  38 +       qeth_clear_outq_buffers(q, 1);
  39         qdio_free_buffers(q->qdio_bufs, QDIO_MAX_BUFFERS_PER_Q);
  40         kfree(q);
  41  }
  42 @@ -2529,10 +2530,8 @@ static int qeth_alloc_qdio_buffers(struct qeth_card *card)
  43                 card->qdio.out_qs[i]->bufs[j] = NULL;
  44         }
  45  out_freeoutq:
  46 -       while (i > 0) {
  47 -               qeth_free_qdio_out_buf(card->qdio.out_qs[--i]);
  48 -               qeth_clear_outq_buffers(card->qdio.out_qs[i], 1);
  49 -       }
  50 +       while (i > 0)
  51 +               qeth_free_output_queue(card->qdio.out_qs[--i]);
  52         kfree(card->qdio.out_qs);
  53         card->qdio.out_qs = NULL;
  54  out_freepool:
  55 @@ -2565,10 +2564,8 @@ static void qeth_free_qdio_buffers(struct qeth_card *card)
  56         qeth_free_buffer_pool(card);
  57         /* free outbound qdio_qs */
  58         if (card->qdio.out_qs) {
  59 -               for (i = 0; i < card->qdio.no_out_queues; ++i) {
  60 -                       qeth_clear_outq_buffers(card->qdio.out_qs[i], 1);
  61 -                       qeth_free_qdio_out_buf(card->qdio.out_qs[i]);
  62 -               }
  63 +               for (i = 0; i < card->qdio.no_out_queues; i++)
  64 +                       qeth_free_output_queue(card->qdio.out_qs[i]);
  65                 kfree(card->qdio.out_qs);
  66                 card->qdio.out_qs = NULL;
  67         }
  68 --
  69 2.19.1
  70