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Diffstat (limited to 'net/netfilter/xt_osf.c')
-rw-r--r--net/netfilter/xt_osf.c202
1 files changed, 2 insertions, 200 deletions
diff --git a/net/netfilter/xt_osf.c b/net/netfilter/xt_osf.c
index a34f314a8c238..9cfef73b41075 100644
--- a/net/netfilter/xt_osf.c
+++ b/net/netfilter/xt_osf.c
@@ -37,21 +37,6 @@
#include <net/netfilter/nf_log.h>
#include <linux/netfilter/xt_osf.h>
-struct xt_osf_finger {
- struct rcu_head rcu_head;
- struct list_head finger_entry;
- struct xt_osf_user_finger finger;
-};
-
-enum osf_fmatch_states {
- /* Packet does not match the fingerprint */
- FMATCH_WRONG = 0,
- /* Packet matches the fingerprint */
- FMATCH_OK,
- /* Options do not match the fingerprint, but header does */
- FMATCH_OPT_WRONG,
-};
-
/*
* Indexed by dont-fragment bit.
* It is the only constant value in the fingerprint.
@@ -164,200 +149,17 @@ static const struct nfnetlink_subsystem xt_osf_nfnetlink = {
.cb = xt_osf_nfnetlink_callbacks,
};
-static inline int xt_osf_ttl(const struct sk_buff *skb, const struct xt_osf_info *info,
- unsigned char f_ttl)
-{
- const struct iphdr *ip = ip_hdr(skb);
-
- if (info->flags & XT_OSF_TTL) {
- if (info->ttl == XT_OSF_TTL_TRUE)
- return ip->ttl == f_ttl;
- if (info->ttl == XT_OSF_TTL_NOCHECK)
- return 1;
- else if (ip->ttl <= f_ttl)
- return 1;
- else {
- struct in_device *in_dev = __in_dev_get_rcu(skb->dev);
- int ret = 0;
-
- for_ifa(in_dev) {
- if (inet_ifa_match(ip->saddr, ifa)) {
- ret = (ip->ttl == f_ttl);
- break;
- }
- }
- endfor_ifa(in_dev);
-
- return ret;
- }
- }
-
- return ip->ttl == f_ttl;
-}
-
static bool
xt_osf_match_packet(const struct sk_buff *skb, struct xt_action_param *p)
{
const struct xt_osf_info *info = p->matchinfo;
- const struct iphdr *ip = ip_hdr(skb);
- const struct tcphdr *tcp;
- struct tcphdr _tcph;
- int fmatch = FMATCH_WRONG, fcount = 0;
- unsigned int optsize = 0, check_WSS = 0;
- u16 window, totlen, mss = 0;
- bool df;
- const unsigned char *optp = NULL, *_optp = NULL;
- unsigned char opts[MAX_IPOPTLEN];
- const struct xt_osf_finger *kf;
- const struct xt_osf_user_finger *f;
struct net *net = xt_net(p);
if (!info)
return false;
- tcp = skb_header_pointer(skb, ip_hdrlen(skb), sizeof(struct tcphdr), &_tcph);
- if (!tcp)
- return false;
-
- if (!tcp->syn)
- return false;
-
- totlen = ntohs(ip->tot_len);
- df = ntohs(ip->frag_off) & IP_DF;
- window = ntohs(tcp->window);
-
- if (tcp->doff * 4 > sizeof(struct tcphdr)) {
- optsize = tcp->doff * 4 - sizeof(struct tcphdr);
-
- _optp = optp = skb_header_pointer(skb, ip_hdrlen(skb) +
- sizeof(struct tcphdr), optsize, opts);
- }
-
- list_for_each_entry_rcu(kf, &xt_osf_fingers[df], finger_entry) {
- int foptsize, optnum;
-
- f = &kf->finger;
-
- if (!(info->flags & XT_OSF_LOG) && strcmp(info->genre, f->genre))
- continue;
-
- optp = _optp;
- fmatch = FMATCH_WRONG;
-
- if (totlen != f->ss || !xt_osf_ttl(skb, info, f->ttl))
- continue;
-
- /*
- * Should not happen if userspace parser was written correctly.
- */
- if (f->wss.wc >= OSF_WSS_MAX)
- continue;
-
- /* Check options */
-
- foptsize = 0;
- for (optnum = 0; optnum < f->opt_num; ++optnum)
- foptsize += f->opt[optnum].length;
-
- if (foptsize > MAX_IPOPTLEN ||
- optsize > MAX_IPOPTLEN ||
- optsize != foptsize)
- continue;
-
- check_WSS = f->wss.wc;
-
- for (optnum = 0; optnum < f->opt_num; ++optnum) {
- if (f->opt[optnum].kind == (*optp)) {
- __u32 len = f->opt[optnum].length;
- const __u8 *optend = optp + len;
-
- fmatch = FMATCH_OK;
-
- switch (*optp) {
- case OSFOPT_MSS:
- mss = optp[3];
- mss <<= 8;
- mss |= optp[2];
-
- mss = ntohs((__force __be16)mss);
- break;
- case OSFOPT_TS:
- break;
- }
-
- optp = optend;
- } else
- fmatch = FMATCH_OPT_WRONG;
-
- if (fmatch != FMATCH_OK)
- break;
- }
-
- if (fmatch != FMATCH_OPT_WRONG) {
- fmatch = FMATCH_WRONG;
-
- switch (check_WSS) {
- case OSF_WSS_PLAIN:
- if (f->wss.val == 0 || window == f->wss.val)
- fmatch = FMATCH_OK;
- break;
- case OSF_WSS_MSS:
- /*
- * Some smart modems decrease mangle MSS to
- * SMART_MSS_2, so we check standard, decreased
- * and the one provided in the fingerprint MSS
- * values.
- */
-#define SMART_MSS_1 1460
-#define SMART_MSS_2 1448
- if (window == f->wss.val * mss ||
- window == f->wss.val * SMART_MSS_1 ||
- window == f->wss.val * SMART_MSS_2)
- fmatch = FMATCH_OK;
- break;
- case OSF_WSS_MTU:
- if (window == f->wss.val * (mss + 40) ||
- window == f->wss.val * (SMART_MSS_1 + 40) ||
- window == f->wss.val * (SMART_MSS_2 + 40))
- fmatch = FMATCH_OK;
- break;
- case OSF_WSS_MODULO:
- if ((window % f->wss.val) == 0)
- fmatch = FMATCH_OK;
- break;
- }
- }
-
- if (fmatch != FMATCH_OK)
- continue;
-
- fcount++;
-
- if (info->flags & XT_OSF_LOG)
- nf_log_packet(net, xt_family(p), xt_hooknum(p), skb,
- xt_in(p), xt_out(p), NULL,
- "%s [%s:%s] : %pI4:%d -> %pI4:%d hops=%d\n",
- f->genre, f->version, f->subtype,
- &ip->saddr, ntohs(tcp->source),
- &ip->daddr, ntohs(tcp->dest),
- f->ttl - ip->ttl);
-
- if ((info->flags & XT_OSF_LOG) &&
- info->loglevel == XT_OSF_LOGLEVEL_FIRST)
- break;
- }
-
- if (!fcount && (info->flags & XT_OSF_LOG))
- nf_log_packet(net, xt_family(p), xt_hooknum(p), skb, xt_in(p),
- xt_out(p), NULL,
- "Remote OS is not known: %pI4:%u -> %pI4:%u\n",
- &ip->saddr, ntohs(tcp->source),
- &ip->daddr, ntohs(tcp->dest));
-
- if (fcount)
- fmatch = FMATCH_OK;
-
- return fmatch == FMATCH_OK;
+ return nf_osf_match(skb, xt_family(p), xt_hooknum(p), xt_in(p),
+ xt_out(p), info, net, xt_osf_fingers);
}
static struct xt_match xt_osf_match = {
generated by cgit v1.2.3 (git 2.39.1) at 2024-04-24 20:40:45 +0000