From: Markus Elfring <elfring@xxxxxxxxxxxxxxxxxxxxx>
Date: Tue, 13 Sep 2016 21:00:44 +0200
* Reuse existing functionality from memdup_user() instead of keeping
duplicate source code.
* Try this copy operation before allocating memory for the local
variable "ksegment".
Signed-off-by: Markus Elfring <elfring@xxxxxxxxxxxxxxxxxxxxx>
---
drivers/char/agp/compat_ioctl.c | 16 ++++------------
1 file changed, 4 insertions(+), 12 deletions(-)
diff --git a/drivers/char/agp/compat_ioctl.c b/drivers/char/agp/compat_ioctl.c
index a2b69db..68d4dc7 100644
--- a/drivers/char/agp/compat_ioctl.c
+++ b/drivers/char/agp/compat_ioctl.c
@@ -98,11 +98,10 @@ static int compat_agpioc_reserve_wrap(struct agp_file_private *priv, void __user
if (ureserve.seg_count >= 16384)
return -EINVAL;
- usegment = kmalloc_array(ureserve.seg_count,
- sizeof(*usegment),
- GFP_KERNEL);
- if (!usegment)
- return -ENOMEM;
+ usegment = memdup_user((void __user *) ureserve.seg_list,
+ sizeof(*usegment) * ureserve.seg_count);
+ if (IS_ERR(usegment))
+ return PTR_ERR(usegment);
ksegment = kmalloc_array(kreserve.seg_count,
sizeof(*ksegment),
@@ -112,13 +111,6 @@ static int compat_agpioc_reserve_wrap(struct agp_file_private *priv, void __user
return -ENOMEM;
}
- if (copy_from_user(usegment, (void __user *) ureserve.seg_list,
- sizeof(*usegment) * ureserve.seg_count)) {
- kfree(usegment);
- kfree(ksegment);
- return -EFAULT;
- }
-
for (seg = 0; seg < ureserve.seg_count; seg++) {
ksegment[seg].pg_start = usegment[seg].pg_start;
ksegment[seg].pg_count = usegment[seg].pg_count;
--
2.10.0
--
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