ip: generate unique IP identificator if local fragmentation is allowed

[ Upstream commit 703133de331a7a7df47f31fb9de51dc6f68a9de8 ]

If local fragmentation is allowed, then ip_select_ident() and
ip_select_ident_more() need to generate unique IDs to ensure
correct defragmentation on the peer.

For example, if IPsec (tunnel mode) has to encrypt large skbs
that have local_df bit set, then all IP fragments that belonged
to different ESP datagrams would have used the same identificator.
If one of these IP fragments would get lost or reordered, then
peer could possibly stitch together wrong IP fragments that did
not belong to the same datagram. This would lead to a packet loss
or data corruption.

Signed-off-by: Ansis Atteka <aatteka@nicira.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/net/pptp.c b/drivers/net/pptp.c
index 4b3a68b69a6744b96fc83658ee3f87d31c931776..e6a8ebfa2186baf91ba7a6b64d5e7813cf531a41 100644 (file)
--- a/drivers/net/pptp.c
+++ b/drivers/net/pptp.c
@@ -282,7 +282,7 @@ static int pptp_xmit(struct ppp_channel *chan, struct sk_buff *skb)
        nf_reset(skb);
 
        skb->ip_summed = CHECKSUM_NONE;
-       ip_select_ident(iph, &rt->dst, NULL);
+       ip_select_ident(skb, &rt->dst, NULL);
        ip_send_check(iph);
 
        ip_local_out(skb);

diff --git a/include/net/ip.h b/include/net/ip.h
index 66dd4914920858037c617abedd369f52ed8dc156..2370f47e336a82a0cd12bc9db861cdf282ad5711 100644 (file)
--- a/include/net/ip.h
+++ b/include/net/ip.h
@@ -262,9 +262,11 @@ int ip_dont_fragment(struct sock *sk, struct dst_entry *dst)
 
 extern void __ip_select_ident(struct iphdr *iph, struct dst_entry *dst, int more);
 
-static inline void ip_select_ident(struct iphdr *iph, struct dst_entry *dst, struct sock *sk)
+static inline void ip_select_ident(struct sk_buff *skb, struct dst_entry *dst, struct sock *sk)
 {
-       if (iph->frag_off & htons(IP_DF)) {
+       struct iphdr *iph = ip_hdr(skb);
+
+       if ((iph->frag_off & htons(IP_DF)) && !skb->local_df) {
                /* This is only to work around buggy Windows95/2000
                 * VJ compression implementations.  If the ID field
                 * does not change, they drop every other packet in
@@ -276,9 +278,11 @@ static inline void ip_select_ident(struct iphdr *iph, struct dst_entry *dst, str
                __ip_select_ident(iph, dst, 0);
 }
 
-static inline void ip_select_ident_more(struct iphdr *iph, struct dst_entry *dst, struct sock *sk, int more)
+static inline void ip_select_ident_more(struct sk_buff *skb, struct dst_entry *dst, struct sock *sk, int more)
 {
-       if (iph->frag_off & htons(IP_DF)) {
+       struct iphdr *iph = ip_hdr(skb);
+
+       if ((iph->frag_off & htons(IP_DF)) && !skb->local_df) {
                if (sk && inet_sk(sk)->inet_daddr) {
                        iph->id = htons(inet_sk(sk)->inet_id);
                        inet_sk(sk)->inet_id += 1 + more;

diff --git a/include/net/ipip.h b/include/net/ipip.h
index a32654d52730d751a4c89dd8f8fea98b57add370..4dccfe3bf731f9eb30846ebbf88785c8157ca361 100644 (file)
--- a/include/net/ipip.h
+++ b/include/net/ipip.h
@@ -50,7 +50,7 @@ struct ip_tunnel_prl_entry {
        int pkt_len = skb->len - skb_transport_offset(skb);             \
                                                                        \
        skb->ip_summed = CHECKSUM_NONE;                                 \
-       ip_select_ident(iph, &rt->dst, NULL);                           \
+       ip_select_ident(skb, &rt->dst, NULL);                           \
                                                                        \
        err = ip_local_out(skb);                                        \
        if (likely(net_xmit_eval(err) == 0)) {                          \

diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c
index e0d42dbb33feb9a040cdf2a467028afbd20da2e7..0b83013208d527126cbae62f324451b897909608 100644 (file)
--- a/net/ipv4/igmp.c
+++ b/net/ipv4/igmp.c
@@ -342,7 +342,7 @@ static struct sk_buff *igmpv3_newpack(struct net_device *dev, int size)
        pip->saddr    = fl4.saddr;
        pip->protocol = IPPROTO_IGMP;
        pip->tot_len  = 0;      /* filled in later */
-       ip_select_ident(pip, &rt->dst, NULL);
+       ip_select_ident(skb, &rt->dst, NULL);
        ((u8*)&pip[1])[0] = IPOPT_RA;
        ((u8*)&pip[1])[1] = 4;
        ((u8*)&pip[1])[2] = 0;
@@ -683,7 +683,7 @@ static int igmp_send_report(struct in_device *in_dev, struct ip_mc_list *pmc,
        iph->daddr    = dst;
        iph->saddr    = fl4.saddr;
        iph->protocol = IPPROTO_IGMP;
-       ip_select_ident(iph, &rt->dst, NULL);
+       ip_select_ident(skb, &rt->dst, NULL);
        ((u8*)&iph[1])[0] = IPOPT_RA;
        ((u8*)&iph[1])[1] = 4;
        ((u8*)&iph[1])[2] = 0;

diff --git a/net/ipv4/inetpeer.c b/net/ipv4/inetpeer.c
index 687764544afcecbae158e6a3eb4a3ddad2870031..996df36f5d70a82e83dca912a0afc7e2e86cd9c0 100644 (file)
--- a/net/ipv4/inetpeer.c
+++ b/net/ipv4/inetpeer.c
@@ -31,8 +31,8 @@
  *  At the moment of writing this notes identifier of IP packets is generated
  *  to be unpredictable using this code only for packets subjected
  *  (actually or potentially) to defragmentation.  I.e. DF packets less than
- *  PMTU in size uses a constant ID and do not use this code (see
- *  ip_select_ident() in include/net/ip.h).
+ *  PMTU in size when local fragmentation is disabled use a constant ID and do
+ *  not use this code (see ip_select_ident() in include/net/ip.h).
  *
  *  Route cache entries hold references to our nodes.
  *  New cache entries get references via lookup by destination IP address in

diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index 51a3eec2c7069fa5c866854e2fb25178c41a92fe..dc4bea413853b176879dab4faf5b3ba20fb8e8fb 100644 (file)
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -161,7 +161,7 @@ int ip_build_and_send_pkt(struct sk_buff *skb, struct sock *sk,
        iph->daddr    = (opt && opt->opt.srr ? opt->opt.faddr : daddr);
        iph->saddr    = saddr;
        iph->protocol = sk->sk_protocol;
-       ip_select_ident(iph, &rt->dst, sk);
+       ip_select_ident(skb, &rt->dst, sk);
 
        if (opt && opt->opt.optlen) {
                iph->ihl += opt->opt.optlen>>2;
@@ -397,7 +397,7 @@ packet_routed:
                ip_options_build(skb, &inet_opt->opt, inet->inet_daddr, rt, 0);
        }
 
-       ip_select_ident_more(iph, &rt->dst, sk,
+       ip_select_ident_more(skb, &rt->dst, sk,
                             (skb_shinfo(skb)->gso_segs ?: 1) - 1);
 
        skb->priority = sk->sk_priority;
@@ -1340,7 +1340,7 @@ struct sk_buff *__ip_make_skb(struct sock *sk,
        iph->ihl = 5;
        iph->tos = inet->tos;
        iph->frag_off = df;
-       ip_select_ident(iph, &rt->dst, sk);
+       ip_select_ident(skb, &rt->dst, sk);
        iph->ttl = ttl;
        iph->protocol = sk->sk_protocol;
        iph->saddr = fl4->saddr;

diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index dc8971459cdcaab0fdde4469aea9da331e374fba..033ea7e629a08b61913ec70a886fe4388d00ca47 100644 (file)
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -1575,7 +1575,7 @@ static void ip_encap(struct sk_buff *skb, __be32 saddr, __be32 daddr)
        iph->protocol   =       IPPROTO_IPIP;
        iph->ihl        =       5;
        iph->tot_len    =       htons(skb->len);
-       ip_select_ident(iph, skb_dst(skb), NULL);
+       ip_select_ident(skb, skb_dst(skb), NULL);
        ip_send_check(iph);
 
        memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));

diff --git a/net/ipv4/raw.c b/net/ipv4/raw.c
index 3d8bb189babbad2deaad518d483e80c8a50eb1e6..2ec6e73eaa8b5a1cd6582fff1822309271d779e3 100644 (file)
--- a/net/ipv4/raw.c
+++ b/net/ipv4/raw.c
@@ -379,7 +379,7 @@ static int raw_send_hdrinc(struct sock *sk, struct flowi4 *fl4,
                iph->check   = 0;
                iph->tot_len = htons(length);
                if (!iph->id)
-                       ip_select_ident(iph, &rt->dst, NULL);
+                       ip_select_ident(skb, &rt->dst, NULL);
 
                iph->check = ip_fast_csum((unsigned char *)iph, iph->ihl);
        }

diff --git a/net/ipv4/xfrm4_mode_tunnel.c b/net/ipv4/xfrm4_mode_tunnel.c
index ed4bf11ef9f4709b9418ebeff06789c9b84b77ab..938553efbf8ea647dc586233279dbfc883ed64fe 100644 (file)
--- a/net/ipv4/xfrm4_mode_tunnel.c
+++ b/net/ipv4/xfrm4_mode_tunnel.c
@@ -54,7 +54,7 @@ static int xfrm4_mode_tunnel_output(struct xfrm_state *x, struct sk_buff *skb)
 
        top_iph->frag_off = (flags & XFRM_STATE_NOPMTUDISC) ?
                0 : (XFRM_MODE_SKB_CB(skb)->frag_off & htons(IP_DF));
-       ip_select_ident(top_iph, dst->child, NULL);
+       ip_select_ident(skb, dst->child, NULL);
 
        top_iph->ttl = ip4_dst_hoplimit(dst->child);
 

diff --git a/net/netfilter/ipvs/ip_vs_xmit.c b/net/netfilter/ipvs/ip_vs_xmit.c
index ee319a4338b0f72cd9deb10ce2223cca2bf0b367..ab67dd1166d692be0f79dc7e442f5b2a95f726e6 100644 (file)
--- a/net/netfilter/ipvs/ip_vs_xmit.c
+++ b/net/netfilter/ipvs/ip_vs_xmit.c
@@ -853,7 +853,7 @@ ip_vs_tunnel_xmit(struct sk_buff *skb, struct ip_vs_conn *cp,
        iph->daddr              =       cp->daddr.ip;
        iph->saddr              =       saddr;
        iph->ttl                =       old_iph->ttl;
-       ip_select_ident(iph, &rt->dst, NULL);
+       ip_select_ident(skb, &rt->dst, NULL);
 
        /* Another hack: avoid icmp_send in ip_fragment */
        skb->local_df = 1;