This is a note to let you know that I've just added the patch titled

binder: prevent transactions to context manager from its own process.

to my char-misc git tree which can be found at git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git in the char-misc-linus branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the next -rc kernel release.

If you have any questions about this process, please let me know.

From 49ed96943a8e0c62cc5a9b0a6cfc88be87d1fcec Mon Sep 17 00:00:00 2001

From: Hridya Valsaraju hridya@google.com Date: Mon, 15 Jul 2019 12:18:04 -0700 Subject: binder: prevent transactions to context manager from its own process.

Currently, a transaction to context manager from its own process is prevented by checking if its binder_proc struct is the same as that of the sender. However, this would not catch cases where the process opens the binder device again and uses the new fd to send a transaction to the context manager.

Reported-by: syzbot+8b3c354d33c4ac78bfad@syzkaller.appspotmail.com Signed-off-by: Hridya Valsaraju hridya@google.com Acked-by: Todd Kjos tkjos@google.com Cc: stable stable@vger.kernel.org Link: https://lore.kernel.org/r/20190715191804.112933-1-hridya@google.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/android/binder.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/android/binder.c b/drivers/android/binder.c index 5bde08603fbc..dc1c83eafc22 100644 --- a/drivers/android/binder.c +++ b/drivers/android/binder.c @@ -2988,7 +2988,7 @@ static void binder_transaction(struct binder_proc *proc, else return_error = BR_DEAD_REPLY; mutex_unlock(&context->context_mgr_node_lock); - if (target_node && target_proc == proc) { + if (target_node && target_proc->pid == proc->pid) { binder_user_error("%d:%d got transaction to context manager from process owning it\n", proc->pid, thread->pid); return_error = BR_FAILED_REPLY;