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    SubjectRe: [PATCH] staging: r8188eu: Use memdup_user instead of kmalloc/copy_from_user
    On Fri, Dec 10, 2021 at 11:38:32AM +0800, Jiapeng Chong wrote:
    > Fix following coccicheck warning:
    >
    > ./drivers/staging/r8188eu/os_dep/ioctl_linux.c:4253:8-15: WARNING
    > opportunity for memdup_user.
    >
    > Reported-by: Abaci Robot <abaci@linux.alibaba.com>
    > Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
    > ---
    > drivers/staging/r8188eu/os_dep/ioctl_linux.c | 13 ++++---------
    > 1 file changed, 4 insertions(+), 9 deletions(-)
    >
    > diff --git a/drivers/staging/r8188eu/os_dep/ioctl_linux.c b/drivers/staging/r8188eu/os_dep/ioctl_linux.c
    > index 56adfe4087a8..c6a2fbfe8f26 100644
    > --- a/drivers/staging/r8188eu/os_dep/ioctl_linux.c
    > +++ b/drivers/staging/r8188eu/os_dep/ioctl_linux.c
    > @@ -4250,17 +4250,12 @@ static int rtw_test(
    > DBG_88E("+%s\n", __func__);
    > len = wrqu->data.length;
    >
    > - pbuf = kzalloc(len, GFP_KERNEL);
    > - if (!pbuf) {
    > - DBG_88E("%s: no memory!\n", __func__);
    > - return -ENOMEM;
    > - }
    > -
    > - if (copy_from_user(pbuf, wrqu->data.pointer, len)) {
    > - kfree(pbuf);
    > + pbuf = memdup_user(wrqu->data.pointer, len);

    This code assumes that the user is going to give us a NUL terminated
    string which is not necessarily true. The original code was buggy too.
    Anyway, please fix it. Use strndup_user() and mention that it is a bug
    fix in the commit message:

    pbuf = strndup_user(wrqu->data.pointer, len);

    Add a Fixes tag.

    regards,
    dan carpenter

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