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alistair23-linux
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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>
hifive-unleashed-5.1
David S. Miller 2017-12-03 12:39:15 -05:00
parent bcd1d601e5 b4d1605a8e
commit e4485c7484
3 changed files with 47 additions and 25 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
include/net/tcp.h
View File

@ -844,12 +844,11 @@ static inline int tcp_v6_sdif(const struct sk_buff *skb)
}
#endif
/* TCP_SKB_CB reference means this can not be used from early demux */
static inline bool inet_exact_dif_match(struct net *net, struct sk_buff *skb)
{
#if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)
if (!net->ipv4.sysctl_tcp_l3mdev_accept &&
skb && ipv4_l3mdev_skb(TCP_SKB_CB(skb)->header.h4.flags))
skb && ipv4_l3mdev_skb(IPCB(skb)->flags))
return true;
#endif
return false;

59
net/ipv4/tcp_ipv4.c
View File

@ -1591,6 +1591,34 @@ int tcp_filter(struct sock *sk, struct sk_buff *skb)
}
EXPORT_SYMBOL(tcp_filter);
static void tcp_v4_restore_cb(struct sk_buff *skb)
{
memmove(IPCB(skb), &TCP_SKB_CB(skb)->header.h4,
sizeof(struct inet_skb_parm));
}
static void tcp_v4_fill_cb(struct sk_buff *skb, const struct iphdr *iph,
const struct tcphdr *th)
{
/* This is tricky : We move IPCB at its correct location into TCP_SKB_CB()
* barrier() makes sure compiler wont play fool^Waliasing games.
*/
memmove(&TCP_SKB_CB(skb)->header.h4, IPCB(skb),
sizeof(struct inet_skb_parm));
barrier();
TCP_SKB_CB(skb)->seq = ntohl(th->seq);
TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
skb->len - th->doff * 4);
TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
TCP_SKB_CB(skb)->tcp_tw_isn = 0;
TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph);
TCP_SKB_CB(skb)->sacked = 0;
TCP_SKB_CB(skb)->has_rxtstamp =
skb->tstamp || skb_hwtstamps(skb)->hwtstamp;
}
/*
* From tcp_input.c
*/
@ -1631,24 +1659,6 @@ int tcp_v4_rcv(struct sk_buff *skb)
th = (const struct tcphdr *)skb->data;
iph = ip_hdr(skb);
/* This is tricky : We move IPCB at its correct location into TCP_SKB_CB()
* barrier() makes sure compiler wont play fool^Waliasing games.
*/
memmove(&TCP_SKB_CB(skb)->header.h4, IPCB(skb),
sizeof(struct inet_skb_parm));
barrier();
TCP_SKB_CB(skb)->seq = ntohl(th->seq);
TCP_SKB_CB(skb)->end_seq = (TCP_SKB_CB(skb)->seq + th->syn + th->fin +
skb->len - th->doff * 4);
TCP_SKB_CB(skb)->ack_seq = ntohl(th->ack_seq);
TCP_SKB_CB(skb)->tcp_flags = tcp_flag_byte(th);
TCP_SKB_CB(skb)->tcp_tw_isn = 0;
TCP_SKB_CB(skb)->ip_dsfield = ipv4_get_dsfield(iph);
TCP_SKB_CB(skb)->sacked = 0;
TCP_SKB_CB(skb)->has_rxtstamp =
skb->tstamp || skb_hwtstamps(skb)->hwtstamp;
lookup:
sk = __inet_lookup_skb(&tcp_hashinfo, skb, __tcp_hdrlen(th), th->source,
th->dest, sdif, &refcounted);
@ -1679,14 +1689,19 @@ process:
sock_hold(sk);
refcounted = true;
nsk = NULL;
if (!tcp_filter(sk, skb))
if (!tcp_filter(sk, skb)) {
th = (const struct tcphdr *)skb->data;
iph = ip_hdr(skb);
tcp_v4_fill_cb(skb, iph, th);
nsk = tcp_check_req(sk, skb, req, false);
}
if (!nsk) {
reqsk_put(req);
goto discard_and_relse;
}
if (nsk == sk) {
reqsk_put(req);
tcp_v4_restore_cb(skb);
} else if (tcp_child_process(sk, nsk, skb)) {
tcp_v4_send_reset(nsk, skb);
goto discard_and_relse;
@ -1712,6 +1727,7 @@ process:
goto discard_and_relse;
th = (const struct tcphdr *)skb->data;
iph = ip_hdr(skb);
tcp_v4_fill_cb(skb, iph, th);
skb->dev = NULL;
@ -1742,6 +1758,8 @@ no_tcp_socket:
if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
goto discard_it;
tcp_v4_fill_cb(skb, iph, th);
if (tcp_checksum_complete(skb)) {
csum_error:
__TCP_INC_STATS(net, TCP_MIB_CSUMERRORS);
@ -1768,6 +1786,8 @@ do_time_wait:
goto discard_it;
}
tcp_v4_fill_cb(skb, iph, th);
if (tcp_checksum_complete(skb)) {
inet_twsk_put(inet_twsk(sk));
goto csum_error;
@ -1784,6 +1804,7 @@ do_time_wait:
if (sk2) {
inet_twsk_deschedule_put(inet_twsk(sk));
sk = sk2;
tcp_v4_restore_cb(skb);
refcounted = false;
goto process;
}

10
net/ipv6/tcp_ipv6.c
View File

@ -1454,7 +1454,6 @@ process:
struct sock *nsk;
sk = req->rsk_listener;
tcp_v6_fill_cb(skb, hdr, th);
if (tcp_v6_inbound_md5_hash(sk, skb)) {
sk_drops_add(sk, skb);
reqsk_put(req);
@ -1467,8 +1466,12 @@ process:
sock_hold(sk);
refcounted = true;
nsk = NULL;
if (!tcp_filter(sk, skb))
if (!tcp_filter(sk, skb)) {
th = (const struct tcphdr *)skb->data;
hdr = ipv6_hdr(skb);
tcp_v6_fill_cb(skb, hdr, th);
nsk = tcp_check_req(sk, skb, req, false);
}
if (!nsk) {
reqsk_put(req);
goto discard_and_relse;
@ -1492,8 +1495,6 @@ process:
if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
goto discard_and_relse;
tcp_v6_fill_cb(skb, hdr, th);
if (tcp_v6_inbound_md5_hash(sk, skb))
goto discard_and_relse;
@ -1501,6 +1502,7 @@ process:
goto discard_and_relse;
th = (const struct tcphdr *)skb->data;
hdr = ipv6_hdr(skb);
tcp_v6_fill_cb(skb, hdr, th);
skb->dev = NULL;