git.ipfire.org Git - thirdparty/kernel/stable-queue.git/blob

   1 From foo@baz Fri Feb 23 11:48:40 CET 2018
   2 From: "Gustavo A. R. Silva" <garsilva@embeddedor.com>
   3 Date: Mon, 20 Nov 2017 08:28:14 -0600
   4 Subject: dmaengine: at_hdmac: fix potential NULL pointer dereference in atc_prep_dma_interleaved
   5
   6 From: "Gustavo A. R. Silva" <garsilva@embeddedor.com>
   7
   8
   9 [ Upstream commit 62a277d43d47e74972de44d33bd3763e31992414 ]
  10
  11 _xt_ is being dereferenced before it is null checked, hence there is a
  12 potential null pointer dereference.
  13
  14 Fix this by moving the pointer dereference after _xt_ has been null
  15 checked.
  16
  17 This issue was detected with the help of Coccinelle.
  18
  19 Fixes: 4483320e241c ("dmaengine: Use Pointer xt after NULL check.")
  20 Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
  21 Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com>
  22 Signed-off-by: Vinod Koul <vinod.koul@intel.com>
  23 Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
  24 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  25 ---
  26  drivers/dma/at_hdmac.c |    4 +++-
  27  1 file changed, 3 insertions(+), 1 deletion(-)
  28
  29 --- a/drivers/dma/at_hdmac.c
  30 +++ b/drivers/dma/at_hdmac.c
  31 @@ -709,7 +709,7 @@ atc_prep_dma_interleaved(struct dma_chan
  32                          unsigned long flags)
  33  {
  34         struct at_dma_chan      *atchan = to_at_dma_chan(chan);
  35 -       struct data_chunk       *first = xt->sgl;
  36 +       struct data_chunk       *first;
  37         struct at_desc          *desc = NULL;
  38         size_t                  xfer_count;
  39         unsigned int            dwidth;
  40 @@ -721,6 +721,8 @@ atc_prep_dma_interleaved(struct dma_chan
  41         if (unlikely(!xt || xt->numf != 1 || !xt->frame_size))
  42                 return NULL;
  43
  44 +       first = xt->sgl;
  45 +
  46         dev_info(chan2dev(chan),
  47                  "%s: src=%pad, dest=%pad, numf=%d, frame_size=%d, flags=0x%lx\n",
  48                 __func__, &xt->src_start, &xt->dst_start, xt->numf,