Merge tag 'char-misc-5.6-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc

Pull char/misc fixes from Greg KH:
 "Here are four small char/misc driver fixes for reported issues for
  5.6-rc5.

  These fixes are:

   - binder fix for a potential use-after-free problem found (took two
     tries to get it right)

   - interconnect core fix

   - altera-stapl driver fix

  All four of these have been in linux-next for a while with no reported
  issues"

* tag 'char-misc-5.6-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc:
  binder: prevent UAF for binderfs devices II
  interconnect: Handle memory allocation errors
  altera-stapl: altera_get_note: prevent write beyond end of 'key'
  binder: prevent UAF for binderfs devices

1 files changed, 9 insertions, 0 deletions

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index a6b2082c24f8..e47c8a4c83db 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -5228,6 +5228,7 @@ static int binder_open(struct inode *nodp, struct file *filp)
 		binder_dev = container_of(filp->private_data,
 					  struct binder_device, miscdev);
 	}
+	refcount_inc(&binder_dev->ref);
 	proc->context = &binder_dev->context;
 	binder_alloc_init(&proc->alloc);
 
@@ -5405,6 +5406,7 @@ static int binder_node_release(struct binder_node *node, int refs)
 static void binder_deferred_release(struct binder_proc *proc)
 {
 	struct binder_context *context = proc->context;
+	struct binder_device *device;
 	struct rb_node *n;
 	int threads, nodes, incoming_refs, outgoing_refs, active_transactions;
 
@@ -5421,6 +5423,12 @@ static void binder_deferred_release(struct binder_proc *proc)
 		context->binder_context_mgr_node = NULL;
 	}
 	mutex_unlock(&context->context_mgr_node_lock);
+	device = container_of(proc->context, struct binder_device, context);
+	if (refcount_dec_and_test(&device->ref)) {
+		kfree(context->name);
+		kfree(device);
+	}
+	proc->context = NULL;
 	binder_inner_proc_lock(proc);
 	/*
 	 * Make sure proc stays alive after we
@@ -6077,6 +6085,7 @@ static int __init init_binder_device(const char *name)
 	binder_device->miscdev.minor = MISC_DYNAMIC_MINOR;
 	binder_device->miscdev.name = name;
 
+	refcount_set(&binder_device->ref, 1);
 	binder_device->context.binder_context_mgr_uid = INVALID_UID;
 	binder_device->context.name = name;
 	mutex_init(&binder_device->context.context_mgr_node_lock);