Messages in this thread | | | Date | Fri, 26 Nov 2021 17:00:41 +0100 | From | Greg Kroah-Hartman <> | Subject | Re: [PATCH] w1: Misuse of get_user()/put_user() reported by sparse |
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On Fri, Nov 19, 2021 at 10:15:09AM +0100, Christophe Leroy wrote: > sparse warnings: (new ones prefixed by >>) > >> drivers/w1/slaves/w1_ds28e04.c:342:13: sparse: sparse: incorrect type in initializer (different address spaces) @@ expected char [noderef] __user *_pu_addr @@ got char *buf @@ > drivers/w1/slaves/w1_ds28e04.c:342:13: sparse: expected char [noderef] __user *_pu_addr > drivers/w1/slaves/w1_ds28e04.c:342:13: sparse: got char *buf > >> drivers/w1/slaves/w1_ds28e04.c:356:13: sparse: sparse: incorrect type in initializer (different address spaces) @@ expected char const [noderef] __user *_gu_addr @@ got char const *buf @@ > drivers/w1/slaves/w1_ds28e04.c:356:13: sparse: expected char const [noderef] __user *_gu_addr > drivers/w1/slaves/w1_ds28e04.c:356:13: sparse: got char const *buf > > The buffer buf is a failsafe buffer in kernel space, it's not user > memory hence doesn't deserve the use of get_user() or put_user(). > > Access 'buf' content directly. > > Reported-by: kernel test robot <lkp@intel.com> > Link: https://lore.kernel.org/lkml/202111190526.K5vb7NWC-lkp@intel.com/T/ > Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> > --- > drivers/w1/slaves/w1_ds28e04.c | 10 ++-------- > 1 file changed, 2 insertions(+), 8 deletions(-) > > diff --git a/drivers/w1/slaves/w1_ds28e04.c b/drivers/w1/slaves/w1_ds28e04.c > index e4f336111edc..d75bb16fb7a1 100644 > --- a/drivers/w1/slaves/w1_ds28e04.c > +++ b/drivers/w1/slaves/w1_ds28e04.c > @@ -339,10 +339,7 @@ static BIN_ATTR_RW(pio, 1); > static ssize_t crccheck_show(struct device *dev, struct device_attribute *attr, > char *buf) > { > - if (put_user(w1_enable_crccheck + 0x30, buf)) > - return -EFAULT; > - > - return sizeof(w1_enable_crccheck); > + return sprintf(buf, "%d", w1_enable_crccheck);
This should be sysfs_emit(), right?
> } > > static ssize_t crccheck_store(struct device *dev, struct device_attribute *attr, > @@ -353,11 +350,8 @@ static ssize_t crccheck_store(struct device *dev, struct device_attribute *attr, > if (count != 1 || !buf) > return -EINVAL; > > - if (get_user(val, buf)) > - return -EFAULT; > - > /* convert to decimal */ > - val = val - 0x30; > + val = *buf - 0x30;
Why not use a proper function that can parse a string and turn it into a number?
thanks,
greg k-h
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