From 9306425b70bf1284a037b7461222887aff48cf8d Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Thu, 20 Sep 2018 23:53:06 +0200 Subject: [PATCH] netfilter: ctnetlink: must check mark attributes vs NULL else we will oops (null deref) when the attributes aren't present. Also add back the EOPNOTSUPP in case MARK filtering is requested but kernel doesn't support it. Fixes: 59c08c69c2788 ("netfilter: ctnetlink: Support L3 protocol-filter on flush") Reported-by: syzbot+e45eda8eda6e93a03959@syzkaller.appspotmail.com Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nf_conntrack_netlink.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c index 099a450..4ae8e52 100644 --- a/net/netfilter/nf_conntrack_netlink.c +++ b/net/netfilter/nf_conntrack_netlink.c @@ -832,6 +832,11 @@ ctnetlink_alloc_filter(const struct nlattr * const cda[], u8 family) { struct ctnetlink_filter *filter; +#ifndef CONFIG_NF_CONNTRACK_MARK + if (cda[CTA_MARK] && cda[CTA_MARK_MASK]) + return ERR_PTR(-EOPNOTSUPP); +#endif + filter = kzalloc(sizeof(*filter), GFP_KERNEL); if (filter == NULL) return ERR_PTR(-ENOMEM); @@ -839,8 +844,10 @@ ctnetlink_alloc_filter(const struct nlattr * const cda[], u8 family) filter->family = family; #ifdef CONFIG_NF_CONNTRACK_MARK - filter->mark.val = ntohl(nla_get_be32(cda[CTA_MARK])); - filter->mark.mask = ntohl(nla_get_be32(cda[CTA_MARK_MASK])); + if (cda[CTA_MARK] && cda[CTA_MARK_MASK]) { + filter->mark.val = ntohl(nla_get_be32(cda[CTA_MARK])); + filter->mark.mask = ntohl(nla_get_be32(cda[CTA_MARK_MASK])); + } #endif return filter; } -- 2.7.4