From: Dan Carpenter dan.carpenter@oracle.com
[ Upstream commit ef75e14a6c935eec82abac07ab68e388514e39bc ]
This code reads from the array before verifying that "trig" is a valid index. If the index is wildly out of bounds then reading from an invalid address could lead to an Oops.
Fixes: a8c66b684efa ("staging: comedi: addi_apci_1500: rewrite the subdevice support functions") Signed-off-by: Dan Carpenter dan.carpenter@oracle.com Reviewed-by: Ian Abbott abbotti@mev.co.uk Link: https://lore.kernel.org/r/20200709102936.GA20875@mwanda Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/staging/comedi/drivers/addi_apci_1500.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/drivers/staging/comedi/drivers/addi_apci_1500.c b/drivers/staging/comedi/drivers/addi_apci_1500.c index 63991c49ff230..79a8799b12628 100644 --- a/drivers/staging/comedi/drivers/addi_apci_1500.c +++ b/drivers/staging/comedi/drivers/addi_apci_1500.c @@ -465,9 +465,9 @@ static int apci1500_di_cfg_trig(struct comedi_device *dev, unsigned int lo_mask = data[5] << shift; unsigned int chan_mask = hi_mask | lo_mask; unsigned int old_mask = (1 << shift) - 1; - unsigned int pm = devpriv->pm[trig] & old_mask; - unsigned int pt = devpriv->pt[trig] & old_mask; - unsigned int pp = devpriv->pp[trig] & old_mask; + unsigned int pm; + unsigned int pt; + unsigned int pp;
if (trig > 1) { dev_dbg(dev->class_dev, @@ -480,6 +480,10 @@ static int apci1500_di_cfg_trig(struct comedi_device *dev, return -EINVAL; }
+ pm = devpriv->pm[trig] & old_mask; + pt = devpriv->pt[trig] & old_mask; + pp = devpriv->pp[trig] & old_mask; + switch (data[2]) { case COMEDI_DIGITAL_TRIG_DISABLE: /* clear trigger configuration */