From: Hridya Valsaraju Date: Mon, 15 Jul 2019 19:18:04 +0000 (-0700) Subject: binder: prevent transactions to context manager from its own process. X-Git-Tag: v4.14.135~8 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=74402b5c3f829dcfce4f5a49d49e77dc3bed82c9;p=thirdparty%2Fkernel%2Fstable.git binder: prevent transactions to context manager from its own process. commit 49ed96943a8e0c62cc5a9b0a6cfc88be87d1fcec upstream. 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 Acked-by: Todd Kjos Cc: stable Link: https://lore.kernel.org/r/20190715191804.112933-1-hridya@google.com Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/android/binder.c b/drivers/android/binder.c index 1af9f36f89cfb..e694fd2c4ed0f 100644 --- a/drivers/android/binder.c +++ b/drivers/android/binder.c @@ -2785,7 +2785,7 @@ 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;