linux-kernel - [PATCH v2 4/6] userns: Use copy_from_user_nul() instead of copy_from

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Message-Id: <20260112073039.1185-5-fushuai.wang@linux.dev>
Date: Mon, 12 Jan 2026 15:30:37 +0800
From: Fushuai Wang <fushuai.wang@...ux.dev>
To: tglx@...nel.org,
	peterz@...radead.org,
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Cc: linux-kernel@...r.kernel.org,
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	wangfushuai@...du.com
Subject: [PATCH v2 4/6] userns: Use copy_from_user_nul() instead of copy_from_user()

From: Fushuai Wang <wangfushuai@...du.com>

Use copy_from_user_nul() instead of copy_from_user() to simplify
the code.

No functional change.

Signed-off-by: Fushuai Wang <wangfushuai@...du.com>
---
 kernel/user_namespace.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
index 03cb63883d04..881a05a3502c 100644
--- a/kernel/user_namespace.c
+++ b/kernel/user_namespace.c
@@ -1239,9 +1239,8 @@ ssize_t proc_setgroups_write(struct file *file, const char __user *buf,
 
 	/* What was written? */
 	ret = -EFAULT;
-	if (copy_from_user(kbuf, buf, count))
+	if (copy_from_user_nul(kbuf, buf, count))
 		goto out;
-	kbuf[count] = '\0';
 	pos = kbuf;
 
 	/* What is being requested? */
-- 
2.36.1