Merge branch 'tcp-cb-selinux-corruption'
Eric Dumazet says:
====================
tcp: add tcp_v4_fill_cb()/tcp_v4_restore_cb()
James Morris reported kernel stack corruption bug that
we tracked back to commit 971f10eca1
("tcp: better TCP_SKB_CB
layout to reduce cache line misses")
First patch needs to be backported to kernels >= 3.18,
while second patch needs to be backported to kernels >= 4.9, since
this was the time when inet_exact_dif_match appeared.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
commit
e4485c7484
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@ -844,12 +844,11 @@ static inline int tcp_v6_sdif(const struct sk_buff *skb)
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}
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#endif
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/* TCP_SKB_CB reference means this can not be used from early demux */
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static inline bool inet_exact_dif_match(struct net *net, struct sk_buff *skb)
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{
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#if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)
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if (!net->ipv4.sysctl_tcp_l3mdev_accept &&
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skb && ipv4_l3mdev_skb(TCP_SKB_CB(skb)->header.h4.flags))
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skb && ipv4_l3mdev_skb(IPCB(skb)->flags))
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return true;
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#endif
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return false;
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@ -1591,6 +1591,34 @@ int tcp_filter(struct sock *sk, struct sk_buff *skb)
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}
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EXPORT_SYMBOL(tcp_filter);
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static void tcp_v4_restore_cb(struct sk_buff *skb)
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{
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memmove(IPCB(skb), &TCP_SKB_CB(skb)->header.h4,
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sizeof(struct inet_skb_parm));
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}
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static void tcp_v4_fill_cb(struct sk_buff *skb, const struct iphdr *iph,
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const struct tcphdr *th)
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{
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/* This is tricky : We move IPCB at its correct location into TCP_SKB_CB()
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* barrier() makes sure compiler wont play fool^Waliasing games.
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*/
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memmove(&TCP_SKB_CB(skb)->header.h4, IPCB(skb),
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sizeof(struct inet_skb_parm));
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barrier();
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TCP_SKB_CB(skb)->seq = ntohl(th->seq);
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TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
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skb->len - th->doff * 4);
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TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
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TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
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TCP_SKB_CB(skb)->tcp_tw_isn = 0;
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TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph);
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TCP_SKB_CB(skb)->sacked = 0;
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TCP_SKB_CB(skb)->has_rxtstamp =
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skb->tstamp || skb_hwtstamps(skb)->hwtstamp;
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}
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/*
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* From tcp_input.c
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*/
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@ -1631,24 +1659,6 @@ int tcp_v4_rcv(struct sk_buff *skb)
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th = (const struct tcphdr *)skb->data;
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iph = ip_hdr(skb);
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/* This is tricky : We move IPCB at its correct location into TCP_SKB_CB()
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* barrier() makes sure compiler wont play fool^Waliasing games.
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*/
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memmove(&TCP_SKB_CB(skb)->header.h4, IPCB(skb),
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sizeof(struct inet_skb_parm));
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barrier();
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TCP_SKB_CB(skb)->seq = ntohl(th->seq);
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TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
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skb->len - th->doff * 4);
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TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
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TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
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TCP_SKB_CB(skb)->tcp_tw_isn = 0;
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TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph);
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TCP_SKB_CB(skb)->sacked = 0;
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TCP_SKB_CB(skb)->has_rxtstamp =
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skb->tstamp || skb_hwtstamps(skb)->hwtstamp;
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lookup:
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sk = __inet_lookup_skb(&tcp_hashinfo, skb, __tcp_hdrlen(th), th->source,
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th->dest, sdif, &refcounted);
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@ -1679,14 +1689,19 @@ process:
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sock_hold(sk);
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refcounted = true;
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nsk = NULL;
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if (!tcp_filter(sk, skb))
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if (!tcp_filter(sk, skb)) {
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th = (const struct tcphdr *)skb->data;
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iph = ip_hdr(skb);
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tcp_v4_fill_cb(skb, iph, th);
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nsk = tcp_check_req(sk, skb, req, false);
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}
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if (!nsk) {
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reqsk_put(req);
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goto discard_and_relse;
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}
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if (nsk == sk) {
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reqsk_put(req);
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tcp_v4_restore_cb(skb);
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} else if (tcp_child_process(sk, nsk, skb)) {
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tcp_v4_send_reset(nsk, skb);
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goto discard_and_relse;
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@ -1712,6 +1727,7 @@ process:
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goto discard_and_relse;
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th = (const struct tcphdr *)skb->data;
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iph = ip_hdr(skb);
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tcp_v4_fill_cb(skb, iph, th);
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skb->dev = NULL;
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@ -1742,6 +1758,8 @@ no_tcp_socket:
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if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
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goto discard_it;
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tcp_v4_fill_cb(skb, iph, th);
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if (tcp_checksum_complete(skb)) {
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csum_error:
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__TCP_INC_STATS(net, TCP_MIB_CSUMERRORS);
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@ -1768,6 +1786,8 @@ do_time_wait:
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goto discard_it;
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}
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tcp_v4_fill_cb(skb, iph, th);
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if (tcp_checksum_complete(skb)) {
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inet_twsk_put(inet_twsk(sk));
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goto csum_error;
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@ -1784,6 +1804,7 @@ do_time_wait:
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if (sk2) {
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inet_twsk_deschedule_put(inet_twsk(sk));
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sk = sk2;
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tcp_v4_restore_cb(skb);
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refcounted = false;
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goto process;
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}
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@ -1454,7 +1454,6 @@ process:
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struct sock *nsk;
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sk = req->rsk_listener;
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tcp_v6_fill_cb(skb, hdr, th);
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if (tcp_v6_inbound_md5_hash(sk, skb)) {
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sk_drops_add(sk, skb);
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reqsk_put(req);
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@ -1467,8 +1466,12 @@ process:
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sock_hold(sk);
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refcounted = true;
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nsk = NULL;
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if (!tcp_filter(sk, skb))
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if (!tcp_filter(sk, skb)) {
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th = (const struct tcphdr *)skb->data;
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hdr = ipv6_hdr(skb);
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tcp_v6_fill_cb(skb, hdr, th);
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nsk = tcp_check_req(sk, skb, req, false);
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}
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if (!nsk) {
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reqsk_put(req);
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goto discard_and_relse;
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@ -1492,8 +1495,6 @@ process:
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if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
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goto discard_and_relse;
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tcp_v6_fill_cb(skb, hdr, th);
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if (tcp_v6_inbound_md5_hash(sk, skb))
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goto discard_and_relse;
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@ -1501,6 +1502,7 @@ process:
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goto discard_and_relse;
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th = (const struct tcphdr *)skb->data;
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hdr = ipv6_hdr(skb);
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tcp_v6_fill_cb(skb, hdr, th);
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skb->dev = NULL;
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