linux

iv/linux

History

Tom Rix fe0278843b soundwire: fix double free of dangling pointer

[ Upstream commit 3fbbf2148a406b3e350fe91e6fdd78eb42ecad24 ]

clang static analysis flags this problem

stream.c:844:9: warning: Use of memory after
  it is freed
        kfree(bus->defer_msg.msg->buf);
              ^~~~~~~~~~~~~~~~~~~~~~~

This happens in an error handler cleaning up memory
allocated for elements in a list.

	list_for_each_entry(m_rt, &stream->master_list, stream_node) {
		bus = m_rt->bus;

		kfree(bus->defer_msg.msg->buf);
		kfree(bus->defer_msg.msg);
	}

And is triggered when the call to sdw_bank_switch() fails.
There are a two problems.

First, when sdw_bank_switch() fails, though it frees memory it
does not clear bus's reference 'defer_msg.msg' to that memory.

The second problem is the freeing msg->buf. In some cases
msg will be NULL so this will dereference a null pointer.
Need to check before freeing.

Fixes: 99b8a5d608a6 ("soundwire: Add bank switch routine")
Signed-off-by: Tom Rix <trix@redhat.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20200902202650.14189-1-trix@redhat.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

2020-09-17 13:47:43 +02:00

bus_type.c

soundwire: add debugfs support

2019-08-23 12:01:02 +05:30

bus.c

soundwire: core: add device tree support for slave devices

2019-09-04 13:12:31 +05:30

bus.h

soundwire: core: add device tree support for slave devices

2019-09-04 13:12:31 +05:30

cadence_master.c

soundwire updates for v5.4-rc1