From: Dan Carpenter <dan.carpenter@oracle.com>
To: Ian Abbott <abbotti@mev.co.uk>,
H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: devel@driverdev.osuosl.org,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
kernel-janitors@vger.kernel.org
Subject: [PATCH] staging: comedi: verify array index is correct before using it
Date: Thu, 09 Jul 2020 10:29:36 +0000 [thread overview]
Message-ID: <20200709102936.GA20875@mwanda> (raw)
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>
---
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 45ad4ba92f94..689acd69a1b9 100644
--- a/drivers/staging/comedi/drivers/addi_apci_1500.c
+++ b/drivers/staging/comedi/drivers/addi_apci_1500.c
@@ -456,9 +456,9 @@ 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,
@@ -471,6 +471,10 @@ 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 */
--
2.27.0
next reply other threads:[~2020-07-09 10:29 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-09 10:29 Dan Carpenter [this message]
2020-07-09 11:08 ` [PATCH] staging: comedi: verify array index is correct before using it Ian Abbott
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