In the Linux kernel, the following vulnerability has been resolved:

binder: fix yet another UAF in binder_devices

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.

Affected Software

References

• https://git.kernel.org/stable/c/4a7694f499cae5b83412c5281bf2c961f34f2ed6
• https://git.kernel.org/stable/c/72a726fb5f25fbb31d6060acfb671c1955831245
• https://git.kernel.org/stable/c/9857af0fcff385c75433f2162c30c62eb912ef6d