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From:   Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
To:     vneethv@linux.ibm.com
Cc:     oberpar@linux.ibm.com, hca@linux.ibm.com, gor@linux.ibm.com,
        agordeev@linux.ibm.com, borntraeger@linux.ibm.com,
        svens@linux.ibm.com, linux-s390@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        Jiapeng Chong <jiapeng.chong@linux.alibaba.com>,
        Abaci Robot <abaci@linux.alibaba.com>
Subject: [PATCH v2] s390/chsc: Switch over to memdup_user()
Date:   Wed, 18 Jan 2023 17:58:23 +0800
Message-Id: <20230118095823.18785-1-jiapeng.chong@linux.alibaba.com>
MIME-Version: 1.0
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Use memdup_user rather than duplicating its implementation, this is a
little bit restricted to reduce false positives.

./drivers/s390/cio/chsc_sch.c:703:7-14: WARNING opportunity for
memdup_user.

Link: https://bugzilla.openanolis.cn/show_bug.cgi?id=3785
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
---
Changes in v2:
  -Add free_page((unsigned long)sccl_area); 

 drivers/s390/cio/chsc_sch.c | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/drivers/s390/cio/chsc_sch.c b/drivers/s390/cio/chsc_sch.c
index 180ab899289c..09dcce7ff24b 100644
--- a/drivers/s390/cio/chsc_sch.c
+++ b/drivers/s390/cio/chsc_sch.c
@@ -700,15 +700,13 @@ static int chsc_ioctl_conf_comp_list(void __user *user_ccl)
 	sccl_area = (void *)get_zeroed_page(GFP_KERNEL | GFP_DMA);
 	if (!sccl_area)
 		return -ENOMEM;
-	ccl = kzalloc(sizeof(*ccl), GFP_KERNEL);
-	if (!ccl) {
-		ret = -ENOMEM;
-		goto out_free;
-	}
-	if (copy_from_user(ccl, user_ccl, sizeof(*ccl))) {
-		ret = -EFAULT;
-		goto out_free;
+
+	ccl = memdup_user(user_ccl, sizeof(*ccl));
+	if (IS_ERR(ccl)) {
+		free_page((unsigned long)sccl_area);
+		return PTR_ERR(ccl);
 	}
+
 	sccl_area->request.length = 0x0020;
 	sccl_area->request.code = 0x0030;
 	sccl_area->fmt = ccl->req.fmt;
-- 
2.20.1.7.g153144c