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From: hridya@google.com (Hridya Valsaraju)
Subject: [PATCH] binder: prevent transactions to context manager from its own process.
Date: Mon, 15 Jul 2019 12:18:04 -0700
Message-ID: <20190715191804.112933-1-hridya@google.com> (raw)

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 at syzkaller.appspotmail.com
Signed-off-by: Hridya Valsaraju <hridya at google.com>
---
 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 e4d25ebec5be..89b9cedae088 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -3138,7 +3138,7 @@ 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;
-- 
2.22.0.510.g264f2c817a-goog

             reply index

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-15 19:18 hridya [this message]
2019-07-15 20:36 ` Todd Kjos
2019-10-11 21:59 ` Jann Horn
2019-10-11 22:11   ` Jann Horn
2019-10-14 17:37     ` Hridya Valsaraju
2019-10-14 19:35       ` Jann Horn

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