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w1: Misuse of get_user()/put_user() reported by sparse

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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.

Link: https://lore.kernel.org/lkml/202111190526.K5vb7NWC-lkp@intel.com/T/
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Link: https://lore.kernel.org/r/d14ed8d71ad4372e6839ae427f91441d3ba0e94d.1637946316.git.christophe.leroy@csgroup.eu
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Christophe Leroy 2021-11-26 18:06:46 +01:00 committed by Greg Kroah-Hartman
parent 09184ae9b5
commit 33dc3e3e99
1 changed files with 6 additions and 20 deletions
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26
drivers/w1/slaves/w1_ds28e04.c
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@ -32,7 +32,7 @@ static int w1_strong_pullup = 1;
module_param_named(strong_pullup, w1_strong_pullup, int, 0);
/* enable/disable CRC checking on DS28E04-100 memory accesses */
static char w1_enable_crccheck = 1;
static bool w1_enable_crccheck = true;
#define W1_EEPROM_SIZE 512
#define W1_PAGE_COUNT 16
@ -339,32 +339,18 @@ 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 sysfs_emit(buf, "%d\n", w1_enable_crccheck);
}
static ssize_t crccheck_store(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
char val;
int err = kstrtobool(buf, &w1_enable_crccheck);
if (count != 1 || !buf)
return -EINVAL;
if (err)
return err;
if (get_user(val, buf))
return -EFAULT;
/* convert to decimal */
val = val - 0x30;
if (val != 0 && val != 1)
return -EINVAL;
/* set the new value */
w1_enable_crccheck = val;
return sizeof(w1_enable_crccheck);
return count;
}
static DEVICE_ATTR_RW(crccheck);