| From | Ben Hutchings <> | Date | Thu, 07 Jun 2018 15:05:21 +0100 | Subject | [PATCH 3.16 246/410] binder: check for binder_thread allocation failure in binder_poll() |
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3.16.57-rc1 review patch. If anyone has any objections, please let me know.
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From: Eric Biggers <ebiggers@google.com>
commit f88982679f54f75daa5b8eff3da72508f1e7422f upstream.
If the kzalloc() in binder_get_thread() fails, binder_poll() dereferences the resulting NULL pointer.
Fix it by returning POLLERR if the memory allocation failed.
This bug was found by syzkaller using fault injection.
Reported-by: syzbot <syzkaller@googlegroups.com> Fixes: 457b9a6f09f0 ("Staging: android: add binder driver") Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> [bwh: Backported to 3.16: - Drop the binder global lock before returning - Adjust filename] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> --- --- a/drivers/staging/android/binder.c +++ b/drivers/staging/android/binder.c @@ -2572,6 +2572,10 @@ static unsigned int binder_poll(struct f binder_lock(__func__); thread = binder_get_thread(proc); + if (!thread) { + binder_unlock(__func__); + return POLLERR; + } wait_for_proc_work = thread->transaction_stack == NULL && list_empty(&thread->todo) && thread->return_error == BR_OK;
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