Prev: [PATCH 4/27] drivers/video/via: Use memdup_user
Next: slub: move kmem_cache_node into it's own cacheline
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/isdn/i4l/isdn_ppp.c | 11 +++--------
drivers/isdn/pcbit/drv.c | 10 +++-------
drivers/isdn/sc/ioctl.c | 23 ++++++-----------------
3 files changed, 12 insertions(+), 32 deletions(-)

diff --git a/drivers/isdn/i4l/isdn_ppp.c b/drivers/isdn/i4l/isdn_ppp.c
index f37b8f6..8c46bae 100644
--- a/drivers/isdn/i4l/isdn_ppp.c
+++ b/drivers/isdn/i4l/isdn_ppp.c
@@ -449,14 +449,9 @@ static int get_filter(void __user *arg, struct sock_filter **p)

/* uprog.len is unsigned short, so no overflow here */
len = uprog.len * sizeof(struct sock_filter);
- code = kmalloc(len, GFP_KERNEL);
- if (code == NULL)
- return -ENOMEM;
-
- if (copy_from_user(code, uprog.filter, len)) {
- kfree(code);
- return -EFAULT;
- }
+ code = memdup_user(uprog.filter, len);
+ if (IS_ERR(code))
+ return PTR_ERR(code);

err = sk_chk_filter(code, uprog.len);
if (err) {
diff --git a/drivers/isdn/pcbit/drv.c b/drivers/isdn/pcbit/drv.c
index 123c1d6..1507d2e 100644
--- a/drivers/isdn/pcbit/drv.c
+++ b/drivers/isdn/pcbit/drv.c
@@ -411,14 +411,10 @@ static int pcbit_writecmd(const u_char __user *buf, int len, int driver, int cha
return -EINVAL;
}

- cbuf = kmalloc(len, GFP_KERNEL);
- if (!cbuf)
- return -ENOMEM;
+ cbuf = memdup_user(buf, len);
+ if (IS_ERR(cbuf))
+ return PTR_ERR(cbuf);

- if (copy_from_user(cbuf, buf, len)) {
- kfree(cbuf);
- return -EFAULT;
- }
memcpy_toio(dev->sh_mem, cbuf, len);
kfree(cbuf);
return len;
diff --git a/drivers/isdn/sc/ioctl.c b/drivers/isdn/sc/ioctl.c
index 1081091..43c5dc3 100644
--- a/drivers/isdn/sc/ioctl.c
+++ b/drivers/isdn/sc/ioctl.c
@@ -215,19 +215,13 @@ int sc_ioctl(int card, scs_ioctl *data)
pr_debug("%s: DCBIOSETSPID: ioctl received\n",
sc_adapter[card]->devicename);

- spid = kmalloc(SCIOC_SPIDSIZE, GFP_KERNEL);
- if(!spid) {
- kfree(rcvmsg);
- return -ENOMEM;
- }
-
/*
* Get the spid from user space
*/
- if (copy_from_user(spid, data->dataptr, SCIOC_SPIDSIZE)) {
+ spid = memdup_user(data->dataptr, SCIOC_SPIDSIZE);
+ if (IS_ERR(spid)) {
kfree(rcvmsg);
- kfree(spid);
- return -EFAULT;
+ return PTR_ERR(spid);
}

pr_debug("%s: SCIOCSETSPID: setting channel %d spid to %s\n",
@@ -296,18 +290,13 @@ int sc_ioctl(int card, scs_ioctl *data)
pr_debug("%s: SCIOSETDN: ioctl received\n",
sc_adapter[card]->devicename);

- dn = kmalloc(SCIOC_DNSIZE, GFP_KERNEL);
- if (!dn) {
- kfree(rcvmsg);
- return -ENOMEM;
- }
/*
* Get the spid from user space
*/
- if (copy_from_user(dn, data->dataptr, SCIOC_DNSIZE)) {
+ dn = memdup_user(data->dataptr, SCIOC_DNSIZE);
+ if (IS_ERR(dn)) {
kfree(rcvmsg);
- kfree(dn);
- return -EFAULT;
+ return PTR_ERR(dn);
}

pr_debug("%s: SCIOCSETDN: setting channel %d dn to %s\n",
--
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Prev: [PATCH 4/27] drivers/video/via: Use memdup_user
Next: slub: move kmem_cache_node into it's own cacheline