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    Subject[PATCH 2/27] drivers/net: Use memdup_user
    From: Julia Lawall <julia@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@diku.dk>

    ---
    drivers/net/ppp_generic.c | 11 +++--------
    1 file changed, 3 insertions(+), 8 deletions(-)

    diff --git a/drivers/net/ppp_generic.c b/drivers/net/ppp_generic.c
    index 5441688..da7943d 100644
    --- a/drivers/net/ppp_generic.c
    +++ b/drivers/net/ppp_generic.c
    @@ -539,14 +539,9 @@ static int get_filter(void __user *arg, struct sock_filter **p)
    }

    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) {

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