From e3200ddadcf7f974d8920d2743afbcc9ccf86299 Mon Sep 17 00:00:00 2001 From: Kuniyuki Iwashima Date: Wed, 7 Sep 2022 09:24:08 +0000 Subject: [PATCH] igmp: Fix a data-race around sysctl_igmp_max_memberships. stable inclusion from stable-v4.19.254 commit 97e228a4efe3a751fb9c9a147f6039d5e287824a category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I5Q0SQ CVE: NA -------------------------------- [ 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 Signed-off-by: David S. Miller Signed-off-by: Sasha Levin Signed-off-by: Yongqiang Liu --- 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 48dd4bf96926..670402e7b49b 100644 --- a/net/ipv4/igmp.c +++ b/net/ipv4/igmp.c @@ -2212,7 +2212,7 @@ static 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) -- GitLab