From 87ece583310d47bcf0027e4a77c990bbb010fc5e Mon Sep 17 00:00:00 2001 From: H Hartley Sweeten Date: Thu, 6 Mar 2014 12:02:56 -0700 Subject: [PATCH] staging: comedi: comedi_fops: introduce __comedi_get_user_cmd() The COMEDI_CMD and COMEDI_CMDTEST ioctl functions both copy the comedi_cmd passed by the user from __user memory space to kernel memory space. They then do some basic sanity checking of the cmd before the subdevice (*do_cmdtest) and (*do_cmd) operations are called. Introduce a helper function to handle the copy_from_user() and do the basic sanity checking. Signed-off-by: H Hartley Sweeten Cc: Ian Abbott Signed-off-by: Greg Kroah-Hartman --- drivers/staging/comedi/comedi_fops.c | 95 +++++++++++++--------------- 1 file changed, 45 insertions(+), 50 deletions(-) diff --git a/drivers/staging/comedi/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c index a819e543ed30..bf5265a083f6 100644 --- a/drivers/staging/comedi/comedi_fops.c +++ b/drivers/staging/comedi/comedi_fops.c @@ -1416,41 +1416,65 @@ error: return ret; } -static int do_cmd_ioctl(struct comedi_device *dev, - struct comedi_cmd __user *arg, void *file) +static int __comedi_get_user_cmd(struct comedi_device *dev, + struct comedi_cmd __user *arg, + struct comedi_cmd *cmd) { - struct comedi_cmd cmd; struct comedi_subdevice *s; - struct comedi_async *async; - int ret = 0; - unsigned int __user *user_chanlist; - if (copy_from_user(&cmd, arg, sizeof(cmd))) { + if (copy_from_user(cmd, arg, sizeof(*cmd))) { dev_dbg(dev->class_dev, "bad cmd address\n"); return -EFAULT; } - /* save user's chanlist pointer so it can be restored later */ - user_chanlist = (unsigned int __user *)cmd.chanlist; - if (cmd.subdev >= dev->n_subdevices) { - dev_dbg(dev->class_dev, "%d no such subdevice\n", cmd.subdev); + if (cmd->subdev >= dev->n_subdevices) { + dev_dbg(dev->class_dev, "%d no such subdevice\n", cmd->subdev); return -ENODEV; } - s = &dev->subdevices[cmd.subdev]; - async = s->async; + s = &dev->subdevices[cmd->subdev]; if (s->type == COMEDI_SUBD_UNUSED) { - dev_dbg(dev->class_dev, "%d not valid subdevice\n", cmd.subdev); + dev_dbg(dev->class_dev, "%d not valid subdevice\n", cmd->subdev); return -EIO; } if (!s->do_cmd || !s->do_cmdtest || !s->async) { dev_dbg(dev->class_dev, - "subdevice %i does not support commands\n", cmd.subdev); + "subdevice %d does not support commands\n", cmd->subdev); return -EIO; } + /* make sure channel/gain list isn't too long */ + if (cmd->chanlist_len > s->len_chanlist) { + dev_dbg(dev->class_dev, "channel/gain list too long %d > %d\n", + cmd->chanlist_len, s->len_chanlist); + return -EINVAL; + } + + return 0; +} + +static int do_cmd_ioctl(struct comedi_device *dev, + struct comedi_cmd __user *arg, void *file) +{ + struct comedi_cmd cmd; + struct comedi_subdevice *s; + struct comedi_async *async; + unsigned int __user *user_chanlist; + int ret; + + /* get the user's cmd and do some simple validation */ + ret = __comedi_get_user_cmd(dev, arg, &cmd); + if (ret) + return ret; + + /* save user's chanlist pointer so it can be restored later */ + user_chanlist = (unsigned int __user *)cmd.chanlist; + + s = &dev->subdevices[cmd.subdev]; + async = s->async; + /* are we locked? (ioctl lock) */ if (s->lock && s->lock != file) { dev_dbg(dev->class_dev, "subdevice locked\n"); @@ -1463,13 +1487,6 @@ static int do_cmd_ioctl(struct comedi_device *dev, return -EBUSY; } - /* make sure channel/gain list isn't too long */ - if (cmd.chanlist_len > s->len_chanlist) { - dev_dbg(dev->class_dev, "channel/gain list too long %u > %d\n", - cmd.chanlist_len, s->len_chanlist); - return -EINVAL; - } - /* make sure channel/gain list isn't too short */ if (cmd.chanlist_len < 1) { dev_dbg(dev->class_dev, "channel/gain list too short %u < 1\n", @@ -1566,41 +1583,19 @@ static int do_cmdtest_ioctl(struct comedi_device *dev, { struct comedi_cmd cmd; struct comedi_subdevice *s; - int ret = 0; unsigned int *chanlist = NULL; unsigned int __user *user_chanlist; + int ret; + + /* get the user's cmd and do some simple validation */ + ret = __comedi_get_user_cmd(dev, arg, &cmd); + if (ret) + return ret; - if (copy_from_user(&cmd, arg, sizeof(cmd))) { - dev_dbg(dev->class_dev, "bad cmd address\n"); - return -EFAULT; - } /* save user's chanlist pointer so it can be restored later */ user_chanlist = (unsigned int __user *)cmd.chanlist; - if (cmd.subdev >= dev->n_subdevices) { - dev_dbg(dev->class_dev, "%d no such subdevice\n", cmd.subdev); - return -ENODEV; - } - s = &dev->subdevices[cmd.subdev]; - if (s->type == COMEDI_SUBD_UNUSED) { - dev_dbg(dev->class_dev, "%d not valid subdevice\n", cmd.subdev); - return -EIO; - } - - if (!s->do_cmd || !s->do_cmdtest) { - dev_dbg(dev->class_dev, - "subdevice %i does not support commands\n", cmd.subdev); - return -EIO; - } - - /* make sure channel/gain list isn't too long */ - if (cmd.chanlist_len > s->len_chanlist) { - dev_dbg(dev->class_dev, "channel/gain list too long %d > %d\n", - cmd.chanlist_len, s->len_chanlist); - ret = -EINVAL; - goto cleanup; - } /* load channel/gain list */ if (cmd.chanlist) { -- 2.20.1