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stm class: Fix channel bitmap on 32-bit systems 

Commit 7bd1d4093c ("stm class: Introduce an abstraction for System Trace
Module devices") naively calculates the channel bitmap size in 64-bit
chunks regardless of the size of underlying unsigned long, making the
bitmap half as big on a 32-bit system. This leads to an out of bounds
access with the upper half of the bitmap.

Fix this by using BITS_TO_LONGS. While at it, convert to using
struct_size() for the total size calculation of the master struct.

Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Fixes: 7bd1d4093c ("stm class: Introduce an abstraction for System Trace Module devices")
Reported-by: Mulu He <muluhe@codeaurora.org>
Cc: stable@vger.kernel.org # v4.4+
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Alexander Shishkin 2019-04-17 10:35:35 +03:00 committed by Greg Kroah-Hartman
parent ee496da4c3
commit 51e0f22781
1 changed files with 3 additions and 4 deletions
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7
drivers/hwtracing/stm/core.c
View File

@ -166,11 +166,10 @@ stm_master(struct stm_device *stm, unsigned int idx)
static int stp_master_alloc(struct stm_device *stm, unsigned int idx)
{
struct stp_master *master;
size_t size;
size = ALIGN(stm->data->sw_nchannels, 8) / 8;
size += sizeof(struct stp_master);
master = kzalloc(size, GFP_ATOMIC);
master = kzalloc(struct_size(master, chan_map,
BITS_TO_LONGS(stm->data->sw_nchannels)),
GFP_ATOMIC);
if (!master)
return -ENOMEM;