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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/scsi/sg.c | 11 +++--------
1 file changed, 3 insertions(+), 8 deletions(-)

diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index ef752b2..277ace6 100644
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -1676,14 +1676,9 @@ static int sg_start_req(Sg_request *srp, unsigned char *cmd)
int len, size = sizeof(struct sg_iovec) * iov_count;
struct iovec *iov;

- iov = kmalloc(size, GFP_ATOMIC);
- if (!iov)
- return -ENOMEM;
-
- if (copy_from_user(iov, hp->dxferp, size)) {
- kfree(iov);
- return -EFAULT;
- }
+ iov = memdup_user(hp->dxferp, size);
+ if (IS_ERR(iov))
+ return PTR_ERR(iov);

len = iov_length(iov, iov_count);
if (hp->dxfer_len < len) {
--
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Prev: [PATCH 10/27] drivers/infiniband/core: Use memdup_user
Next: [PATCH 4/27] drivers/video/via: Use memdup_user