From 70c0eb1ca016f7b6be6cd2a47efc4c701ce4488f Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Tue, 4 Sep 2018 16:01:57 +0200 Subject: [PATCH] netfilter: xtables: avoid BUG_ON I see no reason for them, label or timer cannot be NULL, and if they were, we'll crash with null deref anyway. For skb_header_pointer failure, just set hotdrop to true and toss such packet. Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- net/ipv6/netfilter/ip6t_ipv6header.c | 5 ++++- net/ipv6/netfilter/ip6t_rt.c | 10 ++++++++-- net/netfilter/xt_IDLETIMER.c | 4 ---- net/netfilter/xt_SECMARK.c | 2 -- 4 files changed, 12 insertions(+), 9 deletions(-) diff --git a/net/ipv6/netfilter/ip6t_ipv6header.c b/net/ipv6/netfilter/ip6t_ipv6header.c index 8b14744..af737b47 100644 --- a/net/ipv6/netfilter/ip6t_ipv6header.c +++ b/net/ipv6/netfilter/ip6t_ipv6header.c @@ -65,7 +65,10 @@ ipv6header_mt6(const struct sk_buff *skb, struct xt_action_param *par) } hp = skb_header_pointer(skb, ptr, sizeof(_hdr), &_hdr); - BUG_ON(hp == NULL); + if (!hp) { + par->hotdrop = true; + return false; + } /* Calculate the header length */ if (nexthdr == NEXTHDR_FRAGMENT) diff --git a/net/ipv6/netfilter/ip6t_rt.c b/net/ipv6/netfilter/ip6t_rt.c index 2c99b94..21bf6bf 100644 --- a/net/ipv6/netfilter/ip6t_rt.c +++ b/net/ipv6/netfilter/ip6t_rt.c @@ -137,7 +137,10 @@ static bool rt_mt6(const struct sk_buff *skb, struct xt_action_param *par) sizeof(_addr), &_addr); - BUG_ON(ap == NULL); + if (ap == NULL) { + par->hotdrop = true; + return false; + } if (ipv6_addr_equal(ap, &rtinfo->addrs[i])) { pr_debug("i=%d temp=%d;\n", i, temp); @@ -166,7 +169,10 @@ static bool rt_mt6(const struct sk_buff *skb, struct xt_action_param *par) + temp * sizeof(_addr), sizeof(_addr), &_addr); - BUG_ON(ap == NULL); + if (ap == NULL) { + par->hotdrop = true; + return false; + } if (!ipv6_addr_equal(ap, &rtinfo->addrs[temp])) break; diff --git a/net/netfilter/xt_IDLETIMER.c b/net/netfilter/xt_IDLETIMER.c index 5ee8591..c6acfc2 100644 --- a/net/netfilter/xt_IDLETIMER.c +++ b/net/netfilter/xt_IDLETIMER.c @@ -68,8 +68,6 @@ struct idletimer_tg *__idletimer_tg_find_by_label(const char *label) { struct idletimer_tg *entry; - BUG_ON(!label); - list_for_each_entry(entry, &idletimer_tg_list, entry) { if (!strcmp(label, entry->attr.attr.name)) return entry; @@ -172,8 +170,6 @@ static unsigned int idletimer_tg_target(struct sk_buff *skb, pr_debug("resetting timer %s, timeout period %u\n", info->label, info->timeout); - BUG_ON(!info->timer); - mod_timer(&info->timer->timer, msecs_to_jiffies(info->timeout * 1000) + jiffies); diff --git a/net/netfilter/xt_SECMARK.c b/net/netfilter/xt_SECMARK.c index 4ad5fe2..f16202d 100644 --- a/net/netfilter/xt_SECMARK.c +++ b/net/netfilter/xt_SECMARK.c @@ -35,8 +35,6 @@ secmark_tg(struct sk_buff *skb, const struct xt_action_param *par) u32 secmark = 0; const struct xt_secmark_target_info *info = par->targinfo; - BUG_ON(info->mode != mode); - switch (mode) { case SECMARK_MODE_SEL: secmark = info->secid; -- 2.7.4