patch "binder: fix memory leak in error path" added to char-misc-next

patch "binder: fix memory leak in error path" added to char-misc-next

[gregkh]

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

    binder: fix memory leak in error path

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-next 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 also be merged in the next major kernel release
during the merge window.

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


From 1909a671dbc3606685b1daf8b22a16f65ea7edda Mon Sep 17 00:00:00 2001
From: Todd Kjos <tkjos@android.com>
Date: Fri, 21 Jun 2019 10:54:15 -0700
Subject: binder: fix memory leak in error path

syzkallar found a 32-byte memory leak in a rarely executed error
case. The transaction complete work item was not freed if put_user()
failed when writing the BR_TRANSACTION_COMPLETE to the user command
buffer. Fixed by freeing it before put_user() is called.

Reported-by: syzbot+182ce46596c3f2e1eb24@syzkaller.appspotmail.com
Signed-off-by: Todd Kjos <tkjos@google.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/android/binder.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index 748ac489ef7e..8b108e9b31cc 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -4256,6 +4256,8 @@ static int binder_thread_read(struct binder_proc *proc,
 		case BINDER_WORK_TRANSACTION_COMPLETE: {
 			binder_inner_proc_unlock(proc);
 			cmd = BR_TRANSACTION_COMPLETE;
+			kfree(w);
+			binder_stats_deleted(BINDER_STAT_TRANSACTION_COMPLETE);
 			if (put_user(cmd, (uint32_t __user *)ptr))
 				return -EFAULT;
 			ptr += sizeof(uint32_t);
@@ -4264,8 +4266,6 @@ static int binder_thread_read(struct binder_proc *proc,
 			binder_debug(BINDER_DEBUG_TRANSACTION_COMPLETE,
 				     "%d:%d BR_TRANSACTION_COMPLETE\n",
 				     proc->pid, thread->pid);
-			kfree(w);
-			binder_stats_deleted(BINDER_STAT_TRANSACTION_COMPLETE);
 		} break;
 		case BINDER_WORK_NODE: {
 			struct binder_node *node = container_of(w, struct binder_node, work);
-- 
2.22.0