From: Alice Ryhl <aliceryhl@google.com>
To: Carlos Llamas <cmllamas@google.com>
Cc: "Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
"Arve Hjønnevåg" <arve@android.com>,
"Todd Kjos" <tkjos@android.com>,
"Martijn Coenen" <maco@android.com>,
"Joel Fernandes" <joel@joelfernandes.org>,
"Christian Brauner" <brauner@kernel.org>,
"Suren Baghdasaryan" <surenb@google.com>,
"Li Li" <dualli@google.com>,
kernel-team@android.com, stable@vger.kernel.org,
syzbot+4af454407ec393de51d6@syzkaller.appspotmail.com,
"open list:ANDROID DRIVERS" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] binder: fix yet another UAF in binder_devices
Date: Tue, 27 May 2025 11:39:08 +0000 [thread overview]
Message-ID: <aDWkXI83EyznGG2M@google.com> (raw)
In-Reply-To: <20250524220758.915028-1-cmllamas@google.com>
On Sat, May 24, 2025 at 10:07:58PM +0000, Carlos Llamas wrote:
> Commit e77aff5528a18 ("binderfs: fix use-after-free in binder_devices")
> addressed a use-after-free where devices could be released without first
> being removed from the binder_devices list. However, there is a similar
> path in binder_free_proc() that was missed:
>
> ==================================================================
> BUG: KASAN: slab-use-after-free in binder_remove_device+0xd4/0x100
> Write of size 8 at addr ffff0000c773b900 by task umount/467
> CPU: 12 UID: 0 PID: 467 Comm: umount Not tainted 6.15.0-rc7-00138-g57483a362741 #9 PREEMPT
> Hardware name: linux,dummy-virt (DT)
> Call trace:
> binder_remove_device+0xd4/0x100
> binderfs_evict_inode+0x230/0x2f0
> evict+0x25c/0x5dc
> iput+0x304/0x480
> dentry_unlink_inode+0x208/0x46c
> __dentry_kill+0x154/0x530
> [...]
>
> Allocated by task 463:
> __kmalloc_cache_noprof+0x13c/0x324
> binderfs_binder_device_create.isra.0+0x138/0xa60
> binder_ctl_ioctl+0x1ac/0x230
> [...]
>
> Freed by task 215:
> kfree+0x184/0x31c
> binder_proc_dec_tmpref+0x33c/0x4ac
> binder_deferred_func+0xc10/0x1108
> process_one_work+0x520/0xba4
> [...]
> ==================================================================
>
> Call binder_remove_device() within binder_free_proc() to ensure the
> device is removed from the binder_devices list before being kfreed.
>
> Cc: stable@vger.kernel.org
> Fixes: 12d909cac1e1 ("binderfs: add new binder devices to binder_devices")
> Reported-by: syzbot+4af454407ec393de51d6@syzkaller.appspotmail.com
> Closes: https://syzkaller.appspot.com/bug?extid=4af454407ec393de51d6
> Tested-by: syzbot+4af454407ec393de51d6@syzkaller.appspotmail.com
> Signed-off-by: Carlos Llamas <cmllamas@google.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
next prev parent reply other threads:[~2025-05-27 11:39 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-05-24 22:07 [PATCH] binder: fix yet another UAF in binder_devices Carlos Llamas
2025-05-27 11:39 ` Alice Ryhl [this message]
2025-05-28 2:31 ` Tiffany Yang
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