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 --- drivers/android/binder.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/drivers/android/binder.c b/drivers/android/binder.c index 682bbe4ad550..c463ca4a8fff 100644 --- a/drivers/android/binder.c +++ b/drivers/android/binder.c @@ -5241,6 +5241,7 @@ static void binder_free_proc(struct binder_proc *proc) __func__, proc->outstanding_txns); device = container_of(proc->context, struct binder_device, context); if (refcount_dec_and_test(&device->ref)) { + binder_remove_device(device); kfree(proc->context->name); kfree(device); }
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
"'Carlos Llamas' via kernel-team" kernel-team@android.com writes:
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
drivers/android/binder.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/drivers/android/binder.c b/drivers/android/binder.c index 682bbe4ad550..c463ca4a8fff 100644 --- a/drivers/android/binder.c +++ b/drivers/android/binder.c @@ -5241,6 +5241,7 @@ static void binder_free_proc(struct binder_proc *proc) __func__, proc->outstanding_txns); device = container_of(proc->context, struct binder_device, context); if (refcount_dec_and_test(&device->ref)) {
binder_remove_device(device);
Reviewed-by: Tiffany Yang ynaffit@google.com
linux-stable-mirror@lists.linaro.org
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Alice Ryhl -
Carlos Llamas -
Tiffany Yang