1 files changed, 52 insertions, 9 deletions

diff --git a/drivers/comedi/comedi_fops.c b/drivers/comedi/comedi_fops.c
index 3383a7ce27ff..23b7178522ae 100644
--- a/drivers/comedi/comedi_fops.c
+++ b/drivers/comedi/comedi_fops.c
@@ -787,6 +787,7 @@ static int is_device_busy(struct comedi_device *dev)
 	struct comedi_subdevice *s;
 	int i;
 
+	lockdep_assert_held_write(&dev->attach_lock);
 	lockdep_assert_held(&dev->mutex);
 	if (!dev->attached)
 		return 0;
@@ -795,7 +796,16 @@ static int is_device_busy(struct comedi_device *dev)
 		s = &dev->subdevices[i];
 		if (s->busy)
 			return 1;
-		if (s->async && comedi_buf_is_mmapped(s))
+		if (!s->async)
+			continue;
+		if (comedi_buf_is_mmapped(s))
+			return 1;
+		/*
+		 * There may be tasks still waiting on the subdevice's wait
+		 * queue, although they should already be about to be removed
+		 * from it since the subdevice has no active async command.
+		 */
+		if (wq_has_sleeper(&s->async->wait_head))
 			return 1;
 	}
 
@@ -825,15 +835,22 @@ static int do_devconfig_ioctl(struct comedi_device *dev,
 		return -EPERM;
 
 	if (!arg) {
-		if (is_device_busy(dev))
-			return -EBUSY;
+		int rc = 0;
+
 		if (dev->attached) {
-			struct module *driver_module = dev->driver->module;
+			down_write(&dev->attach_lock);
+			if (is_device_busy(dev)) {
+				rc = -EBUSY;
+			} else {
+				struct module *driver_module =
+					dev->driver->module;
 
-			comedi_device_detach(dev);
-			module_put(driver_module);
+				comedi_device_detach_locked(dev);
+				module_put(driver_module);
+			}
+			up_write(&dev->attach_lock);
 		}
-		return 0;
+		return rc;
 	}
 
 	if (copy_from_user(&it, arg, sizeof(it)))
@@ -1556,21 +1573,27 @@ static int do_insnlist_ioctl(struct comedi_device *dev,
 	}
 
 	for (i = 0; i < n_insns; ++i) {
+		unsigned int n = insns[i].n;
+
 		if (insns[i].insn & INSN_MASK_WRITE) {
 			if (copy_from_user(data, insns[i].data,
-					   insns[i].n * sizeof(unsigned int))) {
+					   n * sizeof(unsigned int))) {
 				dev_dbg(dev->class_dev,
 					"copy_from_user failed\n");
 				ret = -EFAULT;
 				goto error;
 			}
+			if (n < MIN_SAMPLES) {
+				memset(&data[n], 0, (MIN_SAMPLES - n) *
+						    sizeof(unsigned int));
+			}
 		}
 		ret = parse_insn(dev, insns + i, data, file);
 		if (ret < 0)
 			goto error;
 		if (insns[i].insn & INSN_MASK_READ) {
 			if (copy_to_user(insns[i].data, data,
-					 insns[i].n * sizeof(unsigned int))) {
+					 n * sizeof(unsigned int))) {
 				dev_dbg(dev->class_dev,
 					"copy_to_user failed\n");
 				ret = -EFAULT;
@@ -1589,6 +1612,16 @@ error:
 	return i;
 }
 
+#define MAX_INSNS   MAX_SAMPLES
+static int check_insnlist_len(struct comedi_device *dev, unsigned int n_insns)
+{
+	if (n_insns > MAX_INSNS) {
+		dev_dbg(dev->class_dev, "insnlist length too large\n");
+		return -EINVAL;
+	}
+	return 0;
+}
+
 /*
  * COMEDI_INSN ioctl
  * synchronous instruction
@@ -1633,6 +1666,10 @@ static int do_insn_ioctl(struct comedi_device *dev,
 			ret = -EFAULT;
 			goto error;
 		}
+		if (insn->n < MIN_SAMPLES) {
+			memset(&data[insn->n], 0,
+			       (MIN_SAMPLES - insn->n) * sizeof(unsigned int));
+		}
 	}
 	ret = parse_insn(dev, insn, data, file);
 	if (ret < 0)
@@ -2239,6 +2276,9 @@ static long comedi_unlocked_ioctl(struct file *file, unsigned int cmd,
 			rc = -EFAULT;
 			break;
 		}
+		rc = check_insnlist_len(dev, insnlist.n_insns);
+		if (rc)
+			break;
 		insns = kcalloc(insnlist.n_insns, sizeof(*insns), GFP_KERNEL);
 		if (!insns) {
 			rc = -ENOMEM;
@@ -3142,6 +3182,9 @@ static int compat_insnlist(struct file *file, unsigned long arg)
 	if (copy_from_user(&insnlist32, compat_ptr(arg), sizeof(insnlist32)))
 		return -EFAULT;
 
+	rc = check_insnlist_len(dev, insnlist32.n_insns);
+	if (rc)
+		return rc;
 	insns = kcalloc(insnlist32.n_insns, sizeof(*insns), GFP_KERNEL);
 	if (!insns)
 		return -ENOMEM;