linux-stable/drivers/android
Todd Kjos c2a035d782 binder: fix race between munmap() and direct reclaim
commit 5cec2d2e58 upstream.

An munmap() on a binder device causes binder_vma_close() to be called
which clears the alloc->vma pointer.

If direct reclaim causes binder_alloc_free_page() to be called, there
is a race where alloc->vma is read into a local vma pointer and then
used later after the mm->mmap_sem is acquired. This can result in
calling zap_page_range() with an invalid vma which manifests as a
use-after-free in zap_page_range().

The fix is to check alloc->vma after acquiring the mmap_sem (which we
were acquiring anyway) and skip zap_page_range() if it has changed
to NULL.

Cc: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Todd Kjos <tkjos@google.com>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Cc: stable <stable@vger.kernel.org> # 4.14
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-09 09:18:20 +02:00
..
binder.c binder: fix race that allows malicious free of live buffer 2018-12-05 19:41:26 +01:00
binder_alloc.c binder: fix race between munmap() and direct reclaim 2019-06-09 09:18:20 +02:00
binder_alloc.h binder: fix race that allows malicious free of live buffer 2018-12-05 19:41:26 +01:00
binder_alloc_selftest.c android: binder: Add global lru shrinker to binder 2017-08-28 16:47:17 +02:00
binder_trace.h android: binder: Add shrinker tracepoints 2017-08-28 16:47:17 +02:00
Kconfig License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
Makefile android: binder: Add allocator selftest 2017-08-28 16:47:17 +02:00