Commit 926234f1 authored by Ian Abbott's avatar Ian Abbott Committed by Greg Kroah-Hartman

staging: comedi: addi_apci_1564: check INSN_CONFIG_DIGITAL_TRIG shift

The `INSN_CONFIG` comedi instruction with sub-instruction code
`INSN_CONFIG_DIGITAL_TRIG` includes a base channel in `data[3]`. This is
used as a right shift amount for other bitmask values without being
checked.  Shift amounts greater than or equal to 32 will result in
undefined behavior.  Add code to deal with this.

Fixes: 1e15687e ("staging: comedi: addi_apci_1564: add Change-of-State interrupt subdevice and required functions")
Cc: <stable@vger.kernel.org> #3.17+
Signed-off-by: default avatarIan Abbott <abbotti@mev.co.uk>
Link: https://lore.kernel.org/r/20200717145257.112660-4-abbotti@mev.co.ukSigned-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent fc846e9d
...@@ -331,14 +331,22 @@ static int apci1564_cos_insn_config(struct comedi_device *dev, ...@@ -331,14 +331,22 @@ static int apci1564_cos_insn_config(struct comedi_device *dev,
unsigned int *data) unsigned int *data)
{ {
struct apci1564_private *devpriv = dev->private; struct apci1564_private *devpriv = dev->private;
unsigned int shift, oldmask; unsigned int shift, oldmask, himask, lomask;
switch (data[0]) { switch (data[0]) {
case INSN_CONFIG_DIGITAL_TRIG: case INSN_CONFIG_DIGITAL_TRIG:
if (data[1] != 0) if (data[1] != 0)
return -EINVAL; return -EINVAL;
shift = data[3]; shift = data[3];
oldmask = (1U << shift) - 1; if (shift < 32) {
oldmask = (1U << shift) - 1;
himask = data[4] << shift;
lomask = data[5] << shift;
} else {
oldmask = 0xffffffffu;
himask = 0;
lomask = 0;
}
switch (data[2]) { switch (data[2]) {
case COMEDI_DIGITAL_TRIG_DISABLE: case COMEDI_DIGITAL_TRIG_DISABLE:
devpriv->ctrl = 0; devpriv->ctrl = 0;
...@@ -362,8 +370,8 @@ static int apci1564_cos_insn_config(struct comedi_device *dev, ...@@ -362,8 +370,8 @@ static int apci1564_cos_insn_config(struct comedi_device *dev,
devpriv->mode2 &= oldmask; devpriv->mode2 &= oldmask;
} }
/* configure specified channels */ /* configure specified channels */
devpriv->mode1 |= data[4] << shift; devpriv->mode1 |= himask;
devpriv->mode2 |= data[5] << shift; devpriv->mode2 |= lomask;
break; break;
case COMEDI_DIGITAL_TRIG_ENABLE_LEVELS: case COMEDI_DIGITAL_TRIG_ENABLE_LEVELS:
if (devpriv->ctrl != (APCI1564_DI_IRQ_ENA | if (devpriv->ctrl != (APCI1564_DI_IRQ_ENA |
...@@ -380,8 +388,8 @@ static int apci1564_cos_insn_config(struct comedi_device *dev, ...@@ -380,8 +388,8 @@ static int apci1564_cos_insn_config(struct comedi_device *dev,
devpriv->mode2 &= oldmask; devpriv->mode2 &= oldmask;
} }
/* configure specified channels */ /* configure specified channels */
devpriv->mode1 |= data[4] << shift; devpriv->mode1 |= himask;
devpriv->mode2 |= data[5] << shift; devpriv->mode2 |= lomask;
break; break;
default: default:
return -EINVAL; return -EINVAL;
......
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