Messages in this thread | | | Date | Fri, 26 Nov 2021 17:10:46 +0100 | Subject | Re: [PATCH] w1: Misuse of get_user()/put_user() reported by sparse | From | Christophe Leroy <> |
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Le 26/11/2021 à 17:00, Greg Kroah-Hartman a écrit : > 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?
Ok
> >> } >> >> 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?
I wanted to keep the change minimal. But I can also replace it with some scanf.
But don't we have any generic function to read and store a bool after all ?
Thanks Christophe
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