From 3fbfd2223a271426509830e6340c386a1054cfad Mon Sep 17 00:00:00 2001 From: Al Viro Date: Sat, 25 Apr 2020 18:35:03 -0400 Subject: [PATCH] comedi: get rid of compat_alloc_user_space() mess in COMEDI_CHANINFO compat Just take copy_from_user() out of do_chaninfo_ioctl() into the caller and have compat_chaninfo() build a native version and pass it to do_chaninfo_ioctl() directly. Signed-off-by: Al Viro --- drivers/staging/comedi/comedi_fops.c | 68 ++++++++++++---------------- 1 file changed, 30 insertions(+), 38 deletions(-) diff --git a/drivers/staging/comedi/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c index ecd29f28673c..ab811735cd1b 100644 --- a/drivers/staging/comedi/comedi_fops.c +++ b/drivers/staging/comedi/comedi_fops.c @@ -1049,31 +1049,28 @@ static int do_subdinfo_ioctl(struct comedi_device *dev, * array of range table lengths to chaninfo->range_table_list if requested */ static int do_chaninfo_ioctl(struct comedi_device *dev, - struct comedi_chaninfo __user *arg) + struct comedi_chaninfo *it) { struct comedi_subdevice *s; - struct comedi_chaninfo it; lockdep_assert_held(&dev->mutex); - if (copy_from_user(&it, arg, sizeof(it))) - return -EFAULT; - if (it.subdev >= dev->n_subdevices) + if (it->subdev >= dev->n_subdevices) return -EINVAL; - s = &dev->subdevices[it.subdev]; + s = &dev->subdevices[it->subdev]; - if (it.maxdata_list) { + if (it->maxdata_list) { if (s->maxdata || !s->maxdata_list) return -EINVAL; - if (copy_to_user(it.maxdata_list, s->maxdata_list, + if (copy_to_user(it->maxdata_list, s->maxdata_list, s->n_chan * sizeof(unsigned int))) return -EFAULT; } - if (it.flaglist) + if (it->flaglist) return -EINVAL; /* flaglist not supported */ - if (it.rangelist) { + if (it->rangelist) { int i; if (!s->range_table_list) @@ -1081,9 +1078,9 @@ static int do_chaninfo_ioctl(struct comedi_device *dev, for (i = 0; i < s->n_chan; i++) { int x; - x = (dev->minor << 28) | (it.subdev << 24) | (i << 16) | + x = (dev->minor << 28) | (it->subdev << 24) | (i << 16) | (s->range_table_list[i]->length); - if (put_user(x, it.rangelist + i)) + if (put_user(x, it->rangelist + i)) return -EFAULT; } } @@ -2205,9 +2202,14 @@ static long comedi_unlocked_ioctl(struct file *file, unsigned int cmd, (struct comedi_subdinfo __user *)arg, file); break; - case COMEDI_CHANINFO: - rc = do_chaninfo_ioctl(dev, (void __user *)arg); + case COMEDI_CHANINFO: { + struct comedi_chaninfo it; + if (copy_from_user(&it, (void __user *)arg, sizeof(it))) + rc = -EFAULT; + else + rc = do_chaninfo_ioctl(dev, &it); break; + } case COMEDI_RANGEINFO: rc = do_rangeinfo_ioctl(dev, (void __user *)arg); break; @@ -2874,35 +2876,25 @@ struct comedi32_insnlist_struct { /* Handle 32-bit COMEDI_CHANINFO ioctl. */ static int compat_chaninfo(struct file *file, unsigned long arg) { - struct comedi_chaninfo __user *chaninfo; - struct comedi32_chaninfo_struct __user *chaninfo32; + struct comedi_file *cfp = file->private_data; + struct comedi_device *dev = cfp->dev; + struct comedi32_chaninfo_struct chaninfo32; + struct comedi_chaninfo chaninfo; int err; - union { - unsigned int uint; - compat_uptr_t uptr; - } temp; - chaninfo32 = compat_ptr(arg); - chaninfo = compat_alloc_user_space(sizeof(*chaninfo)); - - /* Copy chaninfo structure. Ignore unused members. */ - if (!access_ok(chaninfo32, sizeof(*chaninfo32)) || - !access_ok(chaninfo, sizeof(*chaninfo))) + if (copy_from_user(&chaninfo32, compat_ptr(arg), sizeof(chaninfo32))) return -EFAULT; - err = 0; - err |= __get_user(temp.uint, &chaninfo32->subdev); - err |= __put_user(temp.uint, &chaninfo->subdev); - err |= __get_user(temp.uptr, &chaninfo32->maxdata_list); - err |= __put_user(compat_ptr(temp.uptr), &chaninfo->maxdata_list); - err |= __get_user(temp.uptr, &chaninfo32->flaglist); - err |= __put_user(compat_ptr(temp.uptr), &chaninfo->flaglist); - err |= __get_user(temp.uptr, &chaninfo32->rangelist); - err |= __put_user(compat_ptr(temp.uptr), &chaninfo->rangelist); - if (err) - return -EFAULT; + memset(&chaninfo, 0, sizeof(chaninfo)); + chaninfo.subdev = chaninfo32.subdev; + chaninfo.maxdata_list = compat_ptr(chaninfo32.maxdata_list); + chaninfo.flaglist = compat_ptr(chaninfo32.flaglist); + chaninfo.rangelist = compat_ptr(chaninfo32.rangelist); - return comedi_unlocked_ioctl(file, COMEDI_CHANINFO, (unsigned long)chaninfo); + mutex_lock(&dev->mutex); + err = do_chaninfo_ioctl(dev, &chaninfo); + mutex_unlock(&dev->mutex); + return err; } /* Handle 32-bit COMEDI_RANGEINFO ioctl. */ -- 2.34.1