linux-kernel - [PATCH 4.14 12/37] igmp: Fix a data-race around sysctl_igmp_max

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20220727161001.357244881@linuxfoundation.org>
Date:   Wed, 27 Jul 2022 18:10:38 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Kuniyuki Iwashima <kuniyu@...zon.com>,
        "David S. Miller" <davem@...emloft.net>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.14 12/37] igmp: Fix a data-race around sysctl_igmp_max_memberships.

From: Kuniyuki Iwashima <kuniyu@...zon.com>

[ Upstream commit 6305d821e3b9b5379d348528e5b5faf316383bc2 ]

While reading sysctl_igmp_max_memberships, it can be changed concurrently.
Thus, we need to add READ_ONCE() to its reader.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Kuniyuki Iwashima <kuniyu@...zon.com>
Signed-off-by: David S. Miller <davem@...emloft.net>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 net/ipv4/igmp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c
index 4b3875acc876..fd2c634eeee4 100644
--- a/net/ipv4/igmp.c
+++ b/net/ipv4/igmp.c
@@ -2179,7 +2179,7 @@ int ip_mc_join_group(struct sock *sk, struct ip_mreqn *imr)
 		count++;
 	}
 	err = -ENOBUFS;
-	if (count >= net->ipv4.sysctl_igmp_max_memberships)
+	if (count >= READ_ONCE(net->ipv4.sysctl_igmp_max_memberships))
 		goto done;
 	iml = sock_kmalloc(sk, sizeof(*iml), GFP_KERNEL);
 	if (!iml)
-- 
2.35.1