[NETFILTER]: nf_conntrack: fix invalid conntrack statistics RCU assumption
NF_CT_STAT_INC assumes rcu_read_lock in nf_hook_slow disables preemption as well, making it legal to use __get_cpu_var without disabling preemption manually. The assumption is not correct anymore with preemptable RCU, additionally we need to protect against softirqs when not holding nf_conntrack_lock. Add NF_CT_STAT_INC_ATOMIC macro, which disables local softirqs, and use where necessary. Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
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@ -257,6 +257,12 @@ extern int nf_conntrack_max;
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DECLARE_PER_CPU(struct ip_conntrack_stat, nf_conntrack_stat);
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#define NF_CT_STAT_INC(count) (__get_cpu_var(nf_conntrack_stat).count++)
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#define NF_CT_STAT_INC_ATOMIC(count) \
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do { \
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local_bh_disable(); \
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__get_cpu_var(nf_conntrack_stat).count++; \
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local_bh_enable(); \
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} while (0)
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/* no helper, no nat */
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#define NF_CT_F_BASIC 0
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@ -154,8 +154,8 @@ ipv6_prepare(struct sk_buff **pskb, unsigned int hooknum, unsigned int *dataoff,
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*/
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if ((protoff < 0) || (protoff > (*pskb)->len)) {
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DEBUGP("ip6_conntrack_core: can't find proto in pkt\n");
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NF_CT_STAT_INC(error);
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NF_CT_STAT_INC(invalid);
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NF_CT_STAT_INC_ATOMIC(error);
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NF_CT_STAT_INC_ATOMIC(invalid);
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return -NF_ACCEPT;
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}
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@ -563,7 +563,7 @@ static int early_drop(struct list_head *chain)
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if (del_timer(&ct->timeout)) {
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death_by_timeout((unsigned long)ct);
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dropped = 1;
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NF_CT_STAT_INC(early_drop);
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NF_CT_STAT_INC_ATOMIC(early_drop);
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}
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nf_ct_put(ct);
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return dropped;
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@ -821,7 +821,7 @@ nf_conntrack_in(int pf, unsigned int hooknum, struct sk_buff **pskb)
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/* Previously seen (loopback or untracked)? Ignore. */
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if ((*pskb)->nfct) {
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NF_CT_STAT_INC(ignore);
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NF_CT_STAT_INC_ATOMIC(ignore);
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return NF_ACCEPT;
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}
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@ -840,8 +840,8 @@ nf_conntrack_in(int pf, unsigned int hooknum, struct sk_buff **pskb)
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* core what to do with the packet. */
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if (l4proto->error != NULL &&
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(ret = l4proto->error(*pskb, dataoff, &ctinfo, pf, hooknum)) <= 0) {
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NF_CT_STAT_INC(error);
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NF_CT_STAT_INC(invalid);
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NF_CT_STAT_INC_ATOMIC(error);
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NF_CT_STAT_INC_ATOMIC(invalid);
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return -ret;
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}
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@ -849,13 +849,13 @@ nf_conntrack_in(int pf, unsigned int hooknum, struct sk_buff **pskb)
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&set_reply, &ctinfo);
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if (!ct) {
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/* Not valid part of a connection */
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NF_CT_STAT_INC(invalid);
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NF_CT_STAT_INC_ATOMIC(invalid);
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return NF_ACCEPT;
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}
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if (IS_ERR(ct)) {
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/* Too stressed to deal. */
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NF_CT_STAT_INC(drop);
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NF_CT_STAT_INC_ATOMIC(drop);
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return NF_DROP;
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}
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@ -868,7 +868,7 @@ nf_conntrack_in(int pf, unsigned int hooknum, struct sk_buff **pskb)
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DEBUGP("nf_conntrack_in: Can't track with proto module\n");
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nf_conntrack_put((*pskb)->nfct);
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(*pskb)->nfct = NULL;
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NF_CT_STAT_INC(invalid);
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NF_CT_STAT_INC_ATOMIC(invalid);
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return -ret;
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}
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