linux-kernel - [PATCH v1] x86/mtrr: Convert to use strncpy_from

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Message-Id: <20180515180535.89703-1-andriy.shevchenko@linux.intel.com>
Date:   Tue, 15 May 2018 21:05:35 +0300
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        "H . Peter Anvin" <hpa@...or.com>, x86@...nel.org,
        linux-kernel@...r.kernel.org
Cc:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Subject: [PATCH v1] x86/mtrr: Convert to use strncpy_from_user() helper

Replace the open coded string fetch from the user.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
---
 arch/x86/kernel/cpu/mtrr/if.c | 12 ++----------
 1 file changed, 2 insertions(+), 10 deletions(-)

diff --git a/arch/x86/kernel/cpu/mtrr/if.c b/arch/x86/kernel/cpu/mtrr/if.c
index e4adad68b5e5..3cbae60663fa 100644
--- a/arch/x86/kernel/cpu/mtrr/if.c
+++ b/arch/x86/kernel/cpu/mtrr/if.c
@@ -105,17 +105,9 @@ mtrr_write(struct file *file, const char __user *buf, size_t len, loff_t * ppos)
 
 	memset(line, 0, LINE_SIZE);
 
-	length = len;
-	length--;
-
-	if (length > LINE_SIZE - 1)
-		length = LINE_SIZE - 1;
-
+	length = strncpy_from_user(line, buf, LINE_SIZE - 1);
 	if (length < 0)
-		return -EINVAL;
-
-	if (copy_from_user(line, buf, length))
-		return -EFAULT;
+		return length;
 
 	strim(line);
 
-- 
2.17.0