linux-stable/drivers/android
Jann Horn af0174a63c binder: Handle start==NULL in binder_update_page_range()
commit 2a9edd056e upstream.

The old loop wouldn't stop when reaching `start` if `start==NULL`, instead
continuing backwards to index -1 and crashing.

Luckily you need to be highly privileged to map things at NULL, so it's not
a big problem.

Fix it by adjusting the loop so that the loop variable is always in bounds.

This patch is deliberately minimal to simplify backporting, but IMO this
function could use a refactor. The jump labels in the second loop body are
horrible (the error gotos should be jumping to free_range instead), and
both loops would look nicer if they just iterated upwards through indices.
And the up_read()+mmput() shouldn't be duplicated like that.

Cc: stable@vger.kernel.org
Fixes: 457b9a6f09 ("Staging: android: add binder driver")
Signed-off-by: Jann Horn <jannh@google.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Link: https://lore.kernel.org/r/20191018205631.248274-3-jannh@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-12-13 08:52:52 +01:00
..
Kconfig android: binder: Drop dependency on !M68K 2018-07-07 17:44:52 +02:00
Makefile android: binder: Add allocator selftest 2017-08-28 16:47:17 +02:00
binder.c android: binder: no outgoing transaction when thread todo has transaction 2019-11-20 18:46:42 +01:00
binder_alloc.c binder: Handle start==NULL in binder_update_page_range() 2019-12-13 08:52:52 +01:00
binder_alloc.h binder: fix race that allows malicious free of live buffer 2018-12-05 19:32:11 +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: Show extra_buffers_size in trace 2018-08-02 10:34:12 +02:00