platform/chrome: cros_ec_dev - double fetch bug in ioctl

[cascardo/linux.git] / drivers / platform / chrome / cros_ec_dev.c

diff --git a/drivers/platform/chrome/cros_ec_dev.c b/drivers/platform/chrome/cros_ec_dev.c
index d45cd25..8abd80d 100644 (file)
--- a/drivers/platform/chrome/cros_ec_dev.c
+++ b/drivers/platform/chrome/cros_ec_dev.c
@@ -137,6 +137,10 @@ static long ec_device_ioctl_xcmd(struct cros_ec_dev *ec, void __user *arg)
        if (copy_from_user(&u_cmd, arg, sizeof(u_cmd)))
                return -EFAULT;
 
+       if ((u_cmd.outsize > EC_MAX_MSG_BYTES) ||
+           (u_cmd.insize > EC_MAX_MSG_BYTES))
+               return -EINVAL;
+
        s_cmd = kmalloc(sizeof(*s_cmd) + max(u_cmd.outsize, u_cmd.insize),
                        GFP_KERNEL);
        if (!s_cmd)
@@ -147,13 +151,19 @@ static long ec_device_ioctl_xcmd(struct cros_ec_dev *ec, void __user *arg)
                goto exit;
        }
 
+       if (u_cmd.outsize != s_cmd->outsize ||
+           u_cmd.insize != s_cmd->insize) {
+               ret = -EINVAL;
+               goto exit;
+       }
+
        s_cmd->command += ec->cmd_offset;
        ret = cros_ec_cmd_xfer(ec->ec_dev, s_cmd);
        /* Only copy data to userland if data was received. */
        if (ret < 0)
                goto exit;
 
-       if (copy_to_user(arg, s_cmd, sizeof(*s_cmd) + u_cmd.insize))
+       if (copy_to_user(arg, s_cmd, sizeof(*s_cmd) + s_cmd->insize))
                ret = -EFAULT;
 exit:
        kfree(s_cmd);
@@ -208,6 +218,9 @@ static const struct file_operations fops = {
        .release = ec_device_release,
        .read = ec_device_read,
        .unlocked_ioctl = ec_device_ioctl,
+#ifdef CONFIG_COMPAT
+       .compat_ioctl = ec_device_ioctl,
+#endif
 };
 
 static void __remove(struct device *dev)