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

ANDROID: binder: prevent transactions into 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 7aa135fcf26377f92dc0680a57566b4c7f3e281b Mon Sep 17 00:00:00 2001

From: Martijn Coenen maco@android.com Date: Wed, 28 Mar 2018 11:14:50 +0200 Subject: ANDROID: binder: prevent transactions into own process.

This can't happen with normal nodes (because you can't get a ref to a node you own), but it could happen with the context manager; to make the behavior consistent with regular nodes, reject transactions into the context manager by the process owning it.

Reported-by: syzbot+09e05aba06723a94d43d@syzkaller.appspotmail.com Signed-off-by: Martijn Coenen maco@android.com Cc: stable stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/android/binder.c | 8 ++++++++ 1 file changed, 8 insertions(+)

diff --git a/drivers/android/binder.c b/drivers/android/binder.c index 764b63a5aade..e578eee31589 100644 --- a/drivers/android/binder.c +++ b/drivers/android/binder.c @@ -2839,6 +2839,14 @@ 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) { + binder_user_error("%d:%d got transaction to context manager from process owning it\n", + proc->pid, thread->pid); + return_error = BR_FAILED_REPLY; + return_error_param = -EINVAL; + return_error_line = __LINE__; + goto err_invalid_target_handle; + } } if (!target_node) { /*