Commit 0eb3a49d authored by Alexander Shishkin's avatar Alexander Shishkin Committed by Greg Kroah-Hartman

stm class: Fix channel bitmap on 32-bit systems

commit 51e0f227 upstream.

Commit 7bd1d409 ("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: default avatarAlexander Shishkin <alexander.shishkin@linux.intel.com>
Fixes: 7bd1d409 ("stm class: Introduce an abstraction for System Trace Module devices")
Reported-by: default avatarMulu He <muluhe@codeaurora.org>
Cc: stable@vger.kernel.org # v4.4+
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent ec1db100
......@@ -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;
......
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