linux-kernel - [PATCH -next 1/3] fail_function: Switch to memdup_user

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Message-ID: <20220826073337.2085798-1-yangyingliang@huawei.com>
Date:   Fri, 26 Aug 2022 15:33:35 +0800
From:   Yang Yingliang <yangyingliang@...wei.com>
To:     <linux-kernel@...r.kernel.org>
CC:     <mhiramat@...nel.org>, <ast@...nel.org>, <jbacik@...com>,
        <akpm@...ux-foundation.org>
Subject: [PATCH -next 1/3] fail_function: Switch to memdup_user_nul() helper

Use memdup_user_nul() helper instead of open-coding to
simplify the code.

Signed-off-by: Yang Yingliang <yangyingliang@...wei.com>
---
 kernel/fail_function.c | 13 ++++---------
 1 file changed, 4 insertions(+), 9 deletions(-)

diff --git a/kernel/fail_function.c b/kernel/fail_function.c
index 60dc825ecc2b..03643e33e4c3 100644
--- a/kernel/fail_function.c
+++ b/kernel/fail_function.c
@@ -247,15 +247,11 @@ static ssize_t fei_write(struct file *file, const char __user *buffer,
 	/* cut off if it is too long */
 	if (count > KSYM_NAME_LEN)
 		count = KSYM_NAME_LEN;
-	buf = kmalloc(count + 1, GFP_KERNEL);
-	if (!buf)
-		return -ENOMEM;
 
-	if (copy_from_user(buf, buffer, count)) {
-		ret = -EFAULT;
-		goto out_free;
-	}
-	buf[count] = '\0';
+	buf = memdup_user_nul(buffer, count);
+	if (IS_ERR(buf))
+		return PTR_ERR(buf);
+
 	sym = strstrip(buf);
 
 	mutex_lock(&fei_lock);
@@ -308,7 +304,6 @@ static ssize_t fei_write(struct file *file, const char __user *buffer,
 	}
 out:
 	mutex_unlock(&fei_lock);
-out_free:
 	kfree(buf);
 	return ret;
 }
-- 
2.25.1