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comedi: get rid of compat_alloc_user_space() mess in COMEDI_INSNLIST compat

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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2020-04-25 20:33:04 -04:00
parent aa332e6759
commit b8d47d8813
1 changed files with 48 additions and 90 deletions
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138
drivers/staging/comedi/comedi_fops.c
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@ -1520,34 +1520,19 @@ out:
#define MIN_SAMPLES 16
#define MAX_SAMPLES 65536
static int do_insnlist_ioctl(struct comedi_device *dev,
struct comedi_insnlist __user *arg, void *file)
struct comedi_insn *insns,
unsigned int n_insns,
void *file)
{
struct comedi_insnlist insnlist;
struct comedi_insn *insns = NULL;
unsigned int *data = NULL;
unsigned int max_n_data_required = MIN_SAMPLES;
int i = 0;
int ret = 0;
lockdep_assert_held(&dev->mutex);
if (copy_from_user(&insnlist, arg, sizeof(insnlist)))
return -EFAULT;
insns = kcalloc(insnlist.n_insns, sizeof(*insns), GFP_KERNEL);
if (!insns) {
ret = -ENOMEM;
goto error;
}
if (copy_from_user(insns, insnlist.insns,
sizeof(*insns) * insnlist.n_insns)) {
dev_dbg(dev->class_dev, "copy_from_user failed\n");
ret = -EFAULT;
goto error;
}
/* Determine maximum memory needed for all instructions. */
for (i = 0; i < insnlist.n_insns; ++i) {
for (i = 0; i < n_insns; ++i) {
if (insns[i].n > MAX_SAMPLES) {
dev_dbg(dev->class_dev,
"number of samples too large\n");
@ -1565,7 +1550,7 @@ static int do_insnlist_ioctl(struct comedi_device *dev,
goto error;
}
for (i = 0; i < insnlist.n_insns; ++i) {
for (i = 0; i < n_insns; ++i) {
if (insns[i].insn & INSN_MASK_WRITE) {
if (copy_from_user(data, insns[i].data,
insns[i].n * sizeof(unsigned int))) {
@ -1592,7 +1577,6 @@ static int do_insnlist_ioctl(struct comedi_device *dev,
}
error:
kfree(insns);
kfree(data);
if (ret < 0)
@ -2236,11 +2220,30 @@ static long comedi_unlocked_ioctl(struct file *file, unsigned int cmd,
rc = do_cmdtest_ioctl(dev, (struct comedi_cmd __user *)arg,
file);
break;
case COMEDI_INSNLIST:
rc = do_insnlist_ioctl(dev,
(struct comedi_insnlist __user *)arg,
file);
case COMEDI_INSNLIST: {
struct comedi_insnlist insnlist;
struct comedi_insn *insns = NULL;
if (copy_from_user(&insnlist, (void __user *)arg,
sizeof(insnlist))) {
rc = -EFAULT;
break;
}
insns = kcalloc(insnlist.n_insns, sizeof(*insns), GFP_KERNEL);
if (!insns) {
rc = -ENOMEM;
break;
}
if (copy_from_user(insns, insnlist.insns,
sizeof(*insns) * insnlist.n_insns)) {
rc = -EFAULT;
kfree(insns);
break;
}
rc = do_insnlist_ioctl(dev, insns, insnlist.n_insns, file);
kfree(insns);
break;
}
case COMEDI_INSN: {
struct comedi_insn insn;
if (copy_from_user(&insn, (void __user *)arg, sizeof(insn)))
@ -3095,83 +3098,38 @@ static int get_compat_insn(struct comedi_insn *insn,
return 0;
}
/* Copy 32-bit insn structure to native insn structure. */
static int __get_compat_insn(struct comedi_insn __user *insn,
struct comedi32_insn_struct __user *insn32)
{
int err;
union {
unsigned int uint;
compat_uptr_t uptr;
} temp;
/* Copy insn structure. Ignore the unused members. */
err = 0;
if (!access_ok(insn32, sizeof(*insn32)) ||
!access_ok(insn, sizeof(*insn)))
return -EFAULT;
err |= __get_user(temp.uint, &insn32->insn);
err |= __put_user(temp.uint, &insn->insn);
err |= __get_user(temp.uint, &insn32->n);
err |= __put_user(temp.uint, &insn->n);
err |= __get_user(temp.uptr, &insn32->data);
err |= __put_user(compat_ptr(temp.uptr), &insn->data);
err |= __get_user(temp.uint, &insn32->subdev);
err |= __put_user(temp.uint, &insn->subdev);
err |= __get_user(temp.uint, &insn32->chanspec);
err |= __put_user(temp.uint, &insn->chanspec);
return err ? -EFAULT : 0;
}
/* Handle 32-bit COMEDI_INSNLIST ioctl. */
static int compat_insnlist(struct file *file, unsigned long arg)
{
struct combined_insnlist {
struct comedi_insnlist insnlist;
struct comedi_insn insn[1];
} __user *s;
struct comedi32_insnlist_struct __user *insnlist32;
struct comedi_file *cfp = file->private_data;
struct comedi_device *dev = cfp->dev;
struct comedi32_insnlist_struct insnlist32;
struct comedi32_insn_struct __user *insn32;
compat_uptr_t uptr;
unsigned int n_insns, n;
int err, rc;
struct comedi_insn *insns;
unsigned int n;
int rc;
insnlist32 = compat_ptr(arg);
/* Get 32-bit insnlist structure. */
if (!access_ok(insnlist32, sizeof(*insnlist32)))
if (copy_from_user(&insnlist32, compat_ptr(arg), sizeof(insnlist32)))
return -EFAULT;
err = 0;
err |= __get_user(n_insns, &insnlist32->n_insns);
err |= __get_user(uptr, &insnlist32->insns);
insn32 = compat_ptr(uptr);
if (err)
return -EFAULT;
/* Allocate user memory to copy insnlist and insns into. */
s = compat_alloc_user_space(offsetof(struct combined_insnlist,
insn[n_insns]));
/* Set native insnlist structure. */
if (!access_ok(&s->insnlist, sizeof(s->insnlist)))
return -EFAULT;
err |= __put_user(n_insns, &s->insnlist.n_insns);
err |= __put_user(&s->insn[0], &s->insnlist.insns);
if (err)
return -EFAULT;
insns = kcalloc(insnlist32.n_insns, sizeof(*insns), GFP_KERNEL);
if (!insns)
return -ENOMEM;
/* Copy insn structures. */
for (n = 0; n < n_insns; n++) {
rc = __get_compat_insn(&s->insn[n], &insn32[n]);
if (rc)
insn32 = compat_ptr(insnlist32.insns);
for (n = 0; n < insnlist32.n_insns; n++) {
rc = get_compat_insn(insns + n, insn32 + n);
if (rc) {
kfree(insns);
return rc;
}
}
return comedi_unlocked_ioctl(file, COMEDI_INSNLIST,
(unsigned long)&s->insnlist);
mutex_lock(&dev->mutex);
rc = do_insnlist_ioctl(dev, insns, insnlist32.n_insns, file);
mutex_unlock(&dev->mutex);
return rc;
}
/* Handle 32-bit COMEDI_INSN ioctl. */