linux-kernel - [PATCH 4.9 006/101] kernfs: Replace strncpy with memcpy

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Message-Id: <20181206143011.974644275@linuxfoundation.org>
Date:   Thu,  6 Dec 2018 15:38:05 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Guenter Roeck <linux@...ck-us.net>,
        Tejun Heo <tj@...nel.org>
Subject: [PATCH 4.9 006/101] kernfs: Replace strncpy with memcpy

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Guenter Roeck <linux@...ck-us.net>

commit 166126c1e54d927c2e8efa2702d420e0ce301fd9 upstream.

gcc 8.1.0 complains:

fs/kernfs/symlink.c:91:3: warning:
	'strncpy' output truncated before terminating nul copying
	as many bytes from a string as its length
fs/kernfs/symlink.c: In function 'kernfs_iop_get_link':
fs/kernfs/symlink.c:88:14: note: length computed here

Using strncpy() is indeed less than perfect since the length of data to
be copied has already been determined with strlen(). Replace strncpy()
with memcpy() to address the warning and optimize the code a little.

Signed-off-by: Guenter Roeck <linux@...ck-us.net>
Acked-by: Tejun Heo <tj@...nel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 fs/kernfs/symlink.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/fs/kernfs/symlink.c
+++ b/fs/kernfs/symlink.c
@@ -88,7 +88,7 @@ static int kernfs_get_target_path(struct
 		int slen = strlen(kn->name);
 
 		len -= slen;
-		strncpy(s + len, kn->name, slen);
+		memcpy(s + len, kn->name, slen);
 		if (len)
 			s[--len] = '/';