releases/5.0.19/stm-class-fix-channel-bitmap-on-32-bit-systems.patch

   1 From 51e0f227812ed81a368de54157ebe14396b4be03 Mon Sep 17 00:00:00 2001
   2 From: Alexander Shishkin <alexander.shishkin@linux.intel.com>
   3 Date: Wed, 17 Apr 2019 10:35:35 +0300
   4 Subject: stm class: Fix channel bitmap on 32-bit systems
   5
   6 From: Alexander Shishkin <alexander.shishkin@linux.intel.com>
   7
   8 commit 51e0f227812ed81a368de54157ebe14396b4be03 upstream.
   9
  10 Commit 7bd1d4093c2f ("stm class: Introduce an abstraction for System Trace
  11 Module devices") naively calculates the channel bitmap size in 64-bit
  12 chunks regardless of the size of underlying unsigned long, making the
  13 bitmap half as big on a 32-bit system. This leads to an out of bounds
  14 access with the upper half of the bitmap.
  15
  16 Fix this by using BITS_TO_LONGS. While at it, convert to using
  17 struct_size() for the total size calculation of the master struct.
  18
  19 Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
  20 Fixes: 7bd1d4093c2f ("stm class: Introduce an abstraction for System Trace Module devices")
  21 Reported-by: Mulu He <muluhe@codeaurora.org>
  22 Cc: stable@vger.kernel.org # v4.4+
  23 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  24
  25 ---
  26  drivers/hwtracing/stm/core.c |    7 +++----
  27  1 file changed, 3 insertions(+), 4 deletions(-)
  28
  29 --- a/drivers/hwtracing/stm/core.c
  30 +++ b/drivers/hwtracing/stm/core.c
  31 @@ -166,11 +166,10 @@ stm_master(struct stm_device *stm, unsig
  32  static int stp_master_alloc(struct stm_device *stm, unsigned int idx)
  33  {
  34         struct stp_master *master;
  35 -       size_t size;
  36
  37 -       size = ALIGN(stm->data->sw_nchannels, 8) / 8;
  38 -       size += sizeof(struct stp_master);
  39 -       master = kzalloc(size, GFP_ATOMIC);
  40 +       master = kzalloc(struct_size(master, chan_map,
  41 +                                    BITS_TO_LONGS(stm->data->sw_nchannels)),
  42 +                        GFP_ATOMIC);
  43         if (!master)
  44                 return -ENOMEM;
  45