linux-kernel - [PATCH 4.19 82/91] binder: fix memory leak in error path

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20190712121626.177607735@linuxfoundation.org>
Date:   Fri, 12 Jul 2019 14:19:25 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        syzbot+182ce46596c3f2e1eb24@...kaller.appspotmail.com,
        Todd Kjos <tkjos@...gle.com>
Subject: [PATCH 4.19 82/91] binder: fix memory leak in error path

From: Todd Kjos <tkjos@...roid.com>

commit 1909a671dbc3606685b1daf8b22a16f65ea7edda upstream.

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@...kaller.appspotmail.com
Signed-off-by: Todd Kjos <tkjos@...gle.com>
Cc: stable <stable@...r.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/android/binder.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -3936,6 +3936,8 @@ retry:
 		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);
@@ -3944,8 +3946,6 @@ retry:
 			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);