From: WANG Cong <xiyou.wangcong@gmail.com>
Date: Mon, 21 Dec 2015 18:55:45 +0000 (-0800)
Subject: addrconf: always initialize sysctl table data
X-Git-Tag: Ubuntu-5.13.0-19.19~16684^2~11
X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=5449a5ca9bc27dd51a462de7ca0b1cd861cd2bd0;p=mirror_ubuntu-jammy-kernel.git

addrconf: always initialize sysctl table data

When sysctl performs restrict writes, it allows to write from
a middle position of a sysctl file, which requires us to initialize
the table data before calling proc_dostring() for the write case.

Fixes: 3d1bec99320d ("ipv6: introduce secret_stable to ipv6_devconf")
Reported-by: Sasha Levin <sasha.levin@oracle.com>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Tested-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 17f8e7ea133b..1f21087accab 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -5369,13 +5369,10 @@ static int addrconf_sysctl_stable_secret(struct ctl_table *ctl, int write,
 		goto out;
 	}
 
-	if (!write) {
-		err = snprintf(str, sizeof(str), "%pI6",
-			       &secret->secret);
-		if (err >= sizeof(str)) {
-			err = -EIO;
-			goto out;
-		}
+	err = snprintf(str, sizeof(str), "%pI6", &secret->secret);
+	if (err >= sizeof(str)) {
+		err = -EIO;
+		goto out;
 	}
 
 	err = proc_dostring(&lctl, write, buffer, lenp, ppos);