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Fri, 19 Nov 2021 10:15:28 +0100 X-Authentication-Warning: PO20335.IDSI0.si.c-s.fr: chleroy set sender to christophe.leroy@csgroup.eu using -f From: Christophe Leroy To: Evgeniy Polyakov , Greg Kroah-Hartman Subject: [PATCH] w1: Misuse of get_user()/put_user() reported by sparse Date: Fri, 19 Nov 2021 10:15:09 +0100 Message-Id: <2163689da6544c289254b3c69848acc36db998f5.1637313047.git.christophe.leroy@csgroup.eu> X-Mailer: git-send-email 2.33.1 MIME-Version: 1.0 X-Developer-Signature: v=1; a=ed25519-sha256; t=1637313307; l=2180; s=20211009; h=from:subject:message-id; bh=q/d/etASjF0BJaz00Cw2nQuOF/9xqsT75b2K9Cobhpw=; b=BZ4sI+SyXh/G9MdGf3byD4ZeBOqz32LykJgsN/lXyYS4KGA4n88TSMhO8wCPf1Zsy+l6pcA/lB+p OPuqwvTDCkwTJLxU8KQksyjCspjbkSPyuwzhK3e06mWs6gIcH7fW X-Developer-Key: i=christophe.leroy@csgroup.eu; a=ed25519; pk=HIzTzUj91asvincQGOFx6+ZF5AoUuP9GdOtQChs7Mm0= X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, kernel test robot Errors-To: linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" 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 Link: https://lore.kernel.org/lkml/202111190526.K5vb7NWC-lkp@intel.com/T/ Signed-off-by: Christophe Leroy --- 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); } 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; if (val != 0 && val != 1) return -EINVAL;