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From: Julia Lawall on 22 May 2010 04:30
From: Julia Lawall <julia(a)diku.dk>

Use memdup_user when user data is immediately copied into the
allocated region.

The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@
expression from,to,size,flag;
position p;
identifier l1,l2;
@@

- to = \(kmalloc@p\|kzalloc@p\)(size,flag);
+ to = memdup_user(from,size);
if (
- to==NULL
+ IS_ERR(to)
|| ...) {
<+... when != goto l1;
- -ENOMEM
+ PTR_ERR(to)
...+>
}
- if (copy_from_user(to, from, size) != 0) {
- <+... when != goto l2;
- -EFAULT
- ...+>
- }
// </smpl>

Signed-off-by: Julia Lawall <julia(a)diku.dk>

---
drivers/media/dvb/dvb-core/dvb_demux.c | 10 +++-------
drivers/media/video/dabusb.c | 13 ++++---------
2 files changed, 7 insertions(+), 16 deletions(-)

diff --git a/drivers/media/dvb/dvb-core/dvb_demux.c b/drivers/media/dvb/dvb-core/dvb_demux.c
index 977ddba..4a88a3e 100644
--- a/drivers/media/dvb/dvb-core/dvb_demux.c
+++ b/drivers/media/dvb/dvb-core/dvb_demux.c
@@ -1130,13 +1130,9 @@ static int dvbdmx_write(struct dmx_demux *demux, const char __user *buf, size_t
if ((!demux->frontend) || (demux->frontend->source != DMX_MEMORY_FE))
return -EINVAL;

- p = kmalloc(count, GFP_USER);
- if (!p)
- return -ENOMEM;
- if (copy_from_user(p, buf, count)) {
- kfree(p);
- return -EFAULT;
- }
+ p = memdup_user(buf, count);
+ if (IS_ERR(p))
+ return PTR_ERR(p);
if (mutex_lock_interruptible(&dvbdemux->mutex)) {
kfree(p);
return -ERESTARTSYS;
diff --git a/drivers/media/video/dabusb.c b/drivers/media/video/dabusb.c
index 0f50508..5b176bd 100644
--- a/drivers/media/video/dabusb.c
+++ b/drivers/media/video/dabusb.c
@@ -706,16 +706,11 @@ static long dabusb_ioctl (struct file *file, unsigned int cmd, unsigned long arg
switch (cmd) {

case IOCTL_DAB_BULK:
- pbulk = kmalloc(sizeof (bulk_transfer_t), GFP_KERNEL);
+ pbulk = memdup_user((void __user *)arg,
+ sizeof(bulk_transfer_t));

- if (!pbulk) {
- ret = -ENOMEM;
- break;
- }
-
- if (copy_from_user (pbulk, (void __user *) arg, sizeof (bulk_transfer_t))) {
- ret = -EFAULT;
- kfree (pbulk);
+ if (IS_ERR(pbulk)) {
+ ret = PTR_ERR(pbulk);
break;
}

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Prev: [PATCH 23/27] drivers/net/wireless/prism54: Use memdup_user
Next: [PATCH 6/27] drivers/net/cxgb3: Use memdup_user