pktgen: Dont leak kernel memory

[safe/jmp/linux-2.6] / net / netfilter / xt_TCPMSS.c

diff --git a/net/netfilter/xt_TCPMSS.c b/net/netfilter/xt_TCPMSS.c
index a1bc77f..eda64c1 100644 (file)
--- a/net/netfilter/xt_TCPMSS.c
+++ b/net/netfilter/xt_TCPMSS.c
@@ -13,7 +13,10 @@
 #include <linux/ip.h>
 #include <linux/ipv6.h>
 #include <linux/tcp.h>
+#include <net/dst.h>
+#include <net/flow.h>
 #include <net/ipv6.h>
+#include <net/route.h>
 #include <net/tcp.h>
 
 #include <linux/netfilter_ipv4/ip_tables.h>
@@ -24,7 +27,7 @@
 
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Marc Boucher <marc@mbsi.ca>");
-MODULE_DESCRIPTION("x_tables TCP MSS modification module");
+MODULE_DESCRIPTION("Xtables: TCP Maximum Segment Size (MSS) adjustment");
 MODULE_ALIAS("ipt_TCPMSS");
 MODULE_ALIAS("ip6t_TCPMSS");
 
@@ -41,6 +44,7 @@ optlen(const u_int8_t *opt, unsigned int offset)
 static int
 tcpmss_mangle_packet(struct sk_buff *skb,
                     const struct xt_tcpmss_info *info,
+                    unsigned int in_mtu,
                     unsigned int tcphoff,
                     unsigned int minlen)
 {
@@ -69,14 +73,20 @@ tcpmss_mangle_packet(struct sk_buff *skb,
        }
 
        if (info->mss == XT_TCPMSS_CLAMP_PMTU) {
-               if (dst_mtu(skb->dst) <= minlen) {
+               if (dst_mtu(skb_dst(skb)) <= minlen) {
                        if (net_ratelimit())
                                printk(KERN_ERR "xt_TCPMSS: "
                                       "unknown or invalid path-MTU (%u)\n",
-                                      dst_mtu(skb->dst));
+                                      dst_mtu(skb_dst(skb)));
                        return -1;
                }
-               newmss = dst_mtu(skb->dst) - minlen;
+               if (in_mtu <= minlen) {
+                       if (net_ratelimit())
+                               printk(KERN_ERR "xt_TCPMSS: unknown or "
+                                      "invalid path-MTU (%u)\n", in_mtu);
+                       return -1;
+               }
+               newmss = min(dst_mtu(skb_dst(skb)), in_mtu) - minlen;
        } else
                newmss = info->mss;
 
@@ -137,16 +147,42 @@ tcpmss_mangle_packet(struct sk_buff *skb,
        return TCPOLEN_MSS;
 }
 
+static u_int32_t tcpmss_reverse_mtu(const struct sk_buff *skb,
+                                   unsigned int family)
+{
+       struct flowi fl = {};
+       const struct nf_afinfo *ai;
+       struct rtable *rt = NULL;
+       u_int32_t mtu     = ~0U;
+
+       if (family == PF_INET)
+               fl.fl4_dst = ip_hdr(skb)->saddr;
+       else
+               fl.fl6_dst = ipv6_hdr(skb)->saddr;
+
+       rcu_read_lock();
+       ai = nf_get_afinfo(family);
+       if (ai != NULL)
+               ai->route((struct dst_entry **)&rt, &fl);
+       rcu_read_unlock();
+
+       if (rt != NULL) {
+               mtu = dst_mtu(&rt->u.dst);
+               dst_release(&rt->u.dst);
+       }
+       return mtu;
+}
+
 static unsigned int
-tcpmss_tg4(struct sk_buff *skb, const struct net_device *in,
-           const struct net_device *out, unsigned int hooknum,
-           const struct xt_target *target, const void *targinfo)
+tcpmss_tg4(struct sk_buff *skb, const struct xt_target_param *par)
 {
        struct iphdr *iph = ip_hdr(skb);
        __be16 newlen;
        int ret;
 
-       ret = tcpmss_mangle_packet(skb, targinfo, iph->ihl * 4,
+       ret = tcpmss_mangle_packet(skb, par->targinfo,
+                                  tcpmss_reverse_mtu(skb, PF_INET),
+                                  iph->ihl * 4,
                                   sizeof(*iph) + sizeof(struct tcphdr));
        if (ret < 0)
                return NF_DROP;
@@ -161,9 +197,7 @@ tcpmss_tg4(struct sk_buff *skb, const struct net_device *in,
 
 #if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
 static unsigned int
-tcpmss_tg6(struct sk_buff *skb, const struct net_device *in,
-           const struct net_device *out, unsigned int hooknum,
-           const struct xt_target *target, const void *targinfo)
+tcpmss_tg6(struct sk_buff *skb, const struct xt_target_param *par)
 {
        struct ipv6hdr *ipv6h = ipv6_hdr(skb);
        u8 nexthdr;
@@ -174,7 +208,9 @@ tcpmss_tg6(struct sk_buff *skb, const struct net_device *in,
        tcphoff = ipv6_skip_exthdr(skb, sizeof(*ipv6h), &nexthdr);
        if (tcphoff < 0)
                return NF_DROP;
-       ret = tcpmss_mangle_packet(skb, targinfo, tcphoff,
+       ret = tcpmss_mangle_packet(skb, par->targinfo,
+                                  tcpmss_reverse_mtu(skb, PF_INET6),
+                                  tcphoff,
                                   sizeof(*ipv6h) + sizeof(struct tcphdr));
        if (ret < 0)
                return NF_DROP;
@@ -201,16 +237,13 @@ static inline bool find_syn_match(const struct xt_entry_match *m)
        return false;
 }
 
-static bool
-tcpmss_tg4_check(const char *tablename, const void *entry,
-                 const struct xt_target *target, void *targinfo,
-                 unsigned int hook_mask)
+static bool tcpmss_tg4_check(const struct xt_tgchk_param *par)
 {
-       const struct xt_tcpmss_info *info = targinfo;
-       const struct ipt_entry *e = entry;
+       const struct xt_tcpmss_info *info = par->targinfo;
+       const struct ipt_entry *e = par->entryinfo;
 
        if (info->mss == XT_TCPMSS_CLAMP_PMTU &&
-           (hook_mask & ~((1 << NF_INET_FORWARD) |
+           (par->hook_mask & ~((1 << NF_INET_FORWARD) |
                           (1 << NF_INET_LOCAL_OUT) |
                           (1 << NF_INET_POST_ROUTING))) != 0) {
                printk("xt_TCPMSS: path-MTU clamping only supported in "
@@ -224,16 +257,13 @@ tcpmss_tg4_check(const char *tablename, const void *entry,
 }
 
 #if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
-static bool
-tcpmss_tg6_check(const char *tablename, const void *entry,
-                 const struct xt_target *target, void *targinfo,
-                 unsigned int hook_mask)
+static bool tcpmss_tg6_check(const struct xt_tgchk_param *par)
 {
-       const struct xt_tcpmss_info *info = targinfo;
-       const struct ip6t_entry *e = entry;
+       const struct xt_tcpmss_info *info = par->targinfo;
+       const struct ip6t_entry *e = par->entryinfo;
 
        if (info->mss == XT_TCPMSS_CLAMP_PMTU &&
-           (hook_mask & ~((1 << NF_INET_FORWARD) |
+           (par->hook_mask & ~((1 << NF_INET_FORWARD) |
                           (1 << NF_INET_LOCAL_OUT) |
                           (1 << NF_INET_POST_ROUTING))) != 0) {
                printk("xt_TCPMSS: path-MTU clamping only supported in "
@@ -249,7 +279,7 @@ tcpmss_tg6_check(const char *tablename, const void *entry,
 
 static struct xt_target tcpmss_tg_reg[] __read_mostly = {
        {
-               .family         = AF_INET,
+               .family         = NFPROTO_IPV4,
                .name           = "TCPMSS",
                .checkentry     = tcpmss_tg4_check,
                .target         = tcpmss_tg4,
@@ -259,7 +289,7 @@ static struct xt_target tcpmss_tg_reg[] __read_mostly = {
        },
 #if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
        {
-               .family         = AF_INET6,
+               .family         = NFPROTO_IPV6,
                .name           = "TCPMSS",
                .checkentry     = tcpmss_tg6_check,
                .target         = tcpmss_tg6,