diff options
Diffstat (limited to 'sys/contrib/pf/net/pf_osfp.c')
-rw-r--r-- | sys/contrib/pf/net/pf_osfp.c | 564 |
1 files changed, 564 insertions, 0 deletions
diff --git a/sys/contrib/pf/net/pf_osfp.c b/sys/contrib/pf/net/pf_osfp.c new file mode 100644 index 0000000..ce1efee --- /dev/null +++ b/sys/contrib/pf/net/pf_osfp.c @@ -0,0 +1,564 @@ +/* $FreeBSD$ */ +/* $OpenBSD: pf_osfp.c,v 1.10 2004/04/09 19:30:41 frantzen Exp $ */ + +/* + * Copyright (c) 2003 Mike Frantzen <frantzen@w4g.org> + * + * Permission to use, copy, modify, and distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR + * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN + * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF + * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + * + */ + +#include <sys/param.h> +#include <sys/socket.h> +#ifdef _KERNEL +# include <sys/systm.h> +#endif /* _KERNEL */ +#include <sys/mbuf.h> + +#include <netinet/in.h> +#include <netinet/in_systm.h> +#include <netinet/ip.h> +#include <netinet/tcp.h> + +#include <net/if.h> +#include <net/pfvar.h> + +#ifdef INET6 +#include <netinet/ip6.h> +#endif /* INET6 */ + +#ifdef _KERNEL +# define DPFPRINTF(format, x...) \ + if (pf_status.debug >= PF_DEBUG_NOISY) \ + printf(format , ##x) +#ifdef __FreeBSD__ +typedef uma_zone_t pool_t; +#else +typedef struct pool pool_t; +#endif + +#else +/* Userland equivalents so we can lend code to tcpdump et al. */ + +# include <arpa/inet.h> +# include <errno.h> +# include <stdio.h> +# include <stdlib.h> +# include <string.h> +# define pool_t int +# define pool_get(pool, flags) malloc(*(pool)) +# define pool_put(pool, item) free(item) +# define pool_init(pool, size, a, ao, f, m, p) (*(pool)) = (size) + +# ifdef __FreeBSD__ +# define NTOHS(x) (x) = ntohs((u_int16_t)(x)) +# endif + +# ifdef PFDEBUG +# include <sys/stdarg.h> +# define DPFPRINTF(format, x...) fprintf(stderr, format , ##x) +# else +# define DPFPRINTF(format, x...) ((void)0) +# endif /* PFDEBUG */ +#endif /* _KERNEL */ + + +SLIST_HEAD(pf_osfp_list, pf_os_fingerprint) pf_osfp_list; +pool_t pf_osfp_entry_pl; +pool_t pf_osfp_pl; + +struct pf_os_fingerprint *pf_osfp_find(struct pf_osfp_list *, + struct pf_os_fingerprint *, u_int8_t); +struct pf_os_fingerprint *pf_osfp_find_exact(struct pf_osfp_list *, + struct pf_os_fingerprint *); +void pf_osfp_insert(struct pf_osfp_list *, + struct pf_os_fingerprint *); + + +#ifdef _KERNEL +/* + * Passively fingerprint the OS of the host (IPv4 TCP SYN packets only) + * Returns the list of possible OSes. + */ +struct pf_osfp_enlist * +pf_osfp_fingerprint(struct pf_pdesc *pd, struct mbuf *m, int off, + const struct tcphdr *tcp) +{ + struct ip *ip; + char hdr[60]; + + /* XXX don't have a fingerprint database for IPv6 :-( */ + if (pd->af != PF_INET || pd->proto != IPPROTO_TCP || (tcp->th_off << 2) + < sizeof(*tcp)) + return (NULL); + + ip = mtod(m, struct ip *); + if (!pf_pull_hdr(m, off, hdr, tcp->th_off << 2, NULL, NULL, pd->af)) + return (NULL); + + return (pf_osfp_fingerprint_hdr(ip, (struct tcphdr *)hdr)); +} +#endif /* _KERNEL */ + +struct pf_osfp_enlist * +pf_osfp_fingerprint_hdr(const struct ip *ip, const struct tcphdr *tcp) +{ + struct pf_os_fingerprint fp, *fpresult; + int cnt, optlen = 0; + const u_int8_t *optp; + + if ((tcp->th_flags & (TH_SYN|TH_ACK)) != TH_SYN || (ip->ip_off & + htons(IP_OFFMASK))) + return (NULL); + + memset(&fp, 0, sizeof(fp)); + + fp.fp_psize = ntohs(ip->ip_len); + fp.fp_ttl = ip->ip_ttl; + if (ip->ip_off & htons(IP_DF)) + fp.fp_flags |= PF_OSFP_DF; + fp.fp_wsize = ntohs(tcp->th_win); + + + cnt = (tcp->th_off << 2) - sizeof(*tcp); + optp = (const u_int8_t *)((const char *)tcp + sizeof(*tcp)); + for (; cnt > 0; cnt -= optlen, optp += optlen) { + if (*optp == TCPOPT_EOL) + break; + + fp.fp_optcnt++; + if (*optp == TCPOPT_NOP) { + fp.fp_tcpopts = (fp.fp_tcpopts << PF_OSFP_TCPOPT_BITS) | + PF_OSFP_TCPOPT_NOP; + optlen = 1; + } else { + if (cnt < 2) + return (NULL); + optlen = optp[1]; + if (optlen > cnt || optlen < 2) + return (NULL); + switch (*optp) { + case TCPOPT_MAXSEG: + if (optlen >= TCPOLEN_MAXSEG) + memcpy(&fp.fp_mss, &optp[2], + sizeof(fp.fp_mss)); + fp.fp_tcpopts = (fp.fp_tcpopts << + PF_OSFP_TCPOPT_BITS) | PF_OSFP_TCPOPT_MSS; + NTOHS(fp.fp_mss); + break; + case TCPOPT_WINDOW: + if (optlen >= TCPOLEN_WINDOW) + memcpy(&fp.fp_wscale, &optp[2], + sizeof(fp.fp_wscale)); + NTOHS(fp.fp_wscale); + fp.fp_tcpopts = (fp.fp_tcpopts << + PF_OSFP_TCPOPT_BITS) | + PF_OSFP_TCPOPT_WSCALE; + break; + case TCPOPT_SACK_PERMITTED: + fp.fp_tcpopts = (fp.fp_tcpopts << + PF_OSFP_TCPOPT_BITS) | PF_OSFP_TCPOPT_SACK; + break; + case TCPOPT_TIMESTAMP: + if (optlen >= TCPOLEN_TIMESTAMP) { + u_int32_t ts; + memcpy(&ts, &optp[2], sizeof(ts)); + if (ts == 0) + fp.fp_flags |= PF_OSFP_TS0; + + } + fp.fp_tcpopts = (fp.fp_tcpopts << + PF_OSFP_TCPOPT_BITS) | PF_OSFP_TCPOPT_TS; + break; + default: + return (NULL); + } + } + optlen = MAX(optlen, 1); /* paranoia */ + } + + DPFPRINTF("fingerprinted %s:%d %d:%d:%d:%d:%llx (%d) " + "(TS=%s,M=%s%d,W=%s%d)\n", + inet_ntoa(ip->ip_src), ntohs(tcp->th_sport), + fp.fp_wsize, fp.fp_ttl, (fp.fp_flags & PF_OSFP_DF) != 0, + fp.fp_psize, (long long int)fp.fp_tcpopts, fp.fp_optcnt, + (fp.fp_flags & PF_OSFP_TS0) ? "0" : "", + (fp.fp_flags & PF_OSFP_MSS_MOD) ? "%" : + (fp.fp_flags & PF_OSFP_MSS_DC) ? "*" : "", + fp.fp_mss, + (fp.fp_flags & PF_OSFP_WSCALE_MOD) ? "%" : + (fp.fp_flags & PF_OSFP_WSCALE_DC) ? "*" : "", + fp.fp_wscale); + + if ((fpresult = pf_osfp_find(&pf_osfp_list, &fp, + PF_OSFP_MAXTTL_OFFSET))) + return (&fpresult->fp_oses); + return (NULL); +} + +/* Match a fingerprint ID against a list of OSes */ +int +pf_osfp_match(struct pf_osfp_enlist *list, pf_osfp_t os) +{ + struct pf_osfp_entry *entry; + int os_class, os_version, os_subtype; + int en_class, en_version, en_subtype; + + if (os == PF_OSFP_ANY) + return (1); + if (list == NULL) { + DPFPRINTF("osfp no match against %x\n", os); + return (os == PF_OSFP_UNKNOWN); + } + PF_OSFP_UNPACK(os, os_class, os_version, os_subtype); + SLIST_FOREACH(entry, list, fp_entry) { + PF_OSFP_UNPACK(entry->fp_os, en_class, en_version, en_subtype); + if ((os_class == PF_OSFP_ANY || en_class == os_class) && + (os_version == PF_OSFP_ANY || en_version == os_version) && + (os_subtype == PF_OSFP_ANY || en_subtype == os_subtype)) { + DPFPRINTF("osfp matched %s %s %s %x==%x\n", + entry->fp_class_nm, entry->fp_version_nm, + entry->fp_subtype_nm, os, entry->fp_os); + return (1); + } + } + DPFPRINTF("fingerprint 0x%x didn't match\n", os); + return (0); +} + +/* Initialize the OS fingerprint system */ +#ifdef __FreeBSD__ +int +#else +void +#endif +pf_osfp_initialize(void) +{ +#if defined(__FreeBSD__) && defined(_KERNEL) + int error = ENOMEM; + + do { + pf_osfp_entry_pl = pf_osfp_pl = NULL; + UMA_CREATE(pf_osfp_entry_pl, struct pf_osfp_entry, "pfospfen"); + UMA_CREATE(pf_osfp_pl, struct pf_os_fingerprint, "pfosfp"); + error = 0; + } while(0); +#else + pool_init(&pf_osfp_entry_pl, sizeof(struct pf_osfp_entry), 0, 0, 0, + "pfosfpen", &pool_allocator_nointr); + pool_init(&pf_osfp_pl, sizeof(struct pf_os_fingerprint), 0, 0, 0, + "pfosfp", &pool_allocator_nointr); +#endif + SLIST_INIT(&pf_osfp_list); +#ifdef __FreeBSD__ +#ifdef _KERNEL + return (error); +#else + return (0); +#endif +#endif +} + +#if defined(__FreeBSD__) && (_KERNEL) +void +pf_osfp_cleanup(void) +{ + UMA_DESTROY(pf_osfp_entry_pl); + UMA_DESTROY(pf_osfp_pl); +} +#endif + +/* Flush the fingerprint list */ +void +pf_osfp_flush(void) +{ + struct pf_os_fingerprint *fp; + struct pf_osfp_entry *entry; + + while ((fp = SLIST_FIRST(&pf_osfp_list))) { + SLIST_REMOVE_HEAD(&pf_osfp_list, fp_next); + while ((entry = SLIST_FIRST(&fp->fp_oses))) { + SLIST_REMOVE_HEAD(&fp->fp_oses, fp_entry); + pool_put(&pf_osfp_entry_pl, entry); + } + pool_put(&pf_osfp_pl, fp); + } +} + + +/* Add a fingerprint */ +int +pf_osfp_add(struct pf_osfp_ioctl *fpioc) +{ + struct pf_os_fingerprint *fp, fpadd; + struct pf_osfp_entry *entry; + + memset(&fpadd, 0, sizeof(fpadd)); + fpadd.fp_tcpopts = fpioc->fp_tcpopts; + fpadd.fp_wsize = fpioc->fp_wsize; + fpadd.fp_psize = fpioc->fp_psize; + fpadd.fp_mss = fpioc->fp_mss; + fpadd.fp_flags = fpioc->fp_flags; + fpadd.fp_optcnt = fpioc->fp_optcnt; + fpadd.fp_wscale = fpioc->fp_wscale; + fpadd.fp_ttl = fpioc->fp_ttl; + + DPFPRINTF("adding osfp %s %s %s = %s%d:%d:%d:%s%d:0x%llx %d " + "(TS=%s,M=%s%d,W=%s%d) %x\n", + fpioc->fp_os.fp_class_nm, fpioc->fp_os.fp_version_nm, + fpioc->fp_os.fp_subtype_nm, + (fpadd.fp_flags & PF_OSFP_WSIZE_MOD) ? "%" : + (fpadd.fp_flags & PF_OSFP_WSIZE_MSS) ? "S" : + (fpadd.fp_flags & PF_OSFP_WSIZE_MTU) ? "T" : + (fpadd.fp_flags & PF_OSFP_WSIZE_DC) ? "*" : "", + fpadd.fp_wsize, + fpadd.fp_ttl, + (fpadd.fp_flags & PF_OSFP_DF) ? 1 : 0, + (fpadd.fp_flags & PF_OSFP_PSIZE_MOD) ? "%" : + (fpadd.fp_flags & PF_OSFP_PSIZE_DC) ? "*" : "", + fpadd.fp_psize, + (long long int)fpadd.fp_tcpopts, fpadd.fp_optcnt, + (fpadd.fp_flags & PF_OSFP_TS0) ? "0" : "", + (fpadd.fp_flags & PF_OSFP_MSS_MOD) ? "%" : + (fpadd.fp_flags & PF_OSFP_MSS_DC) ? "*" : "", + fpadd.fp_mss, + (fpadd.fp_flags & PF_OSFP_WSCALE_MOD) ? "%" : + (fpadd.fp_flags & PF_OSFP_WSCALE_DC) ? "*" : "", + fpadd.fp_wscale, + fpioc->fp_os.fp_os); + + + if ((fp = pf_osfp_find_exact(&pf_osfp_list, &fpadd))) { + SLIST_FOREACH(entry, &fp->fp_oses, fp_entry) { + if (PF_OSFP_ENTRY_EQ(entry, &fpioc->fp_os)) + return (EEXIST); + } + if ((entry = pool_get(&pf_osfp_entry_pl, PR_NOWAIT)) == NULL) + return (ENOMEM); + } else { + if ((fp = pool_get(&pf_osfp_pl, PR_NOWAIT)) == NULL) + return (ENOMEM); + memset(fp, 0, sizeof(*fp)); + fp->fp_tcpopts = fpioc->fp_tcpopts; + fp->fp_wsize = fpioc->fp_wsize; + fp->fp_psize = fpioc->fp_psize; + fp->fp_mss = fpioc->fp_mss; + fp->fp_flags = fpioc->fp_flags; + fp->fp_optcnt = fpioc->fp_optcnt; + fp->fp_wscale = fpioc->fp_wscale; + fp->fp_ttl = fpioc->fp_ttl; + SLIST_INIT(&fp->fp_oses); + if ((entry = pool_get(&pf_osfp_entry_pl, PR_NOWAIT)) == NULL) { + pool_put(&pf_osfp_pl, fp); + return (ENOMEM); + } + pf_osfp_insert(&pf_osfp_list, fp); + } + memcpy(entry, &fpioc->fp_os, sizeof(*entry)); + + /* Make sure the strings are NUL terminated */ + entry->fp_class_nm[sizeof(entry->fp_class_nm)-1] = '\0'; + entry->fp_version_nm[sizeof(entry->fp_version_nm)-1] = '\0'; + entry->fp_subtype_nm[sizeof(entry->fp_subtype_nm)-1] = '\0'; + + SLIST_INSERT_HEAD(&fp->fp_oses, entry, fp_entry); + +#ifdef PFDEBUG + if ((fp = pf_osfp_validate())) + printf("Invalid fingerprint list\n"); +#endif /* PFDEBUG */ + return (0); +} + + +/* Find a fingerprint in the list */ +struct pf_os_fingerprint * +pf_osfp_find(struct pf_osfp_list *list, struct pf_os_fingerprint *find, + u_int8_t ttldiff) +{ + struct pf_os_fingerprint *f; + +#define MATCH_INT(_MOD, _DC, _field) \ + if ((f->fp_flags & _DC) == 0) { \ + if ((f->fp_flags & _MOD) == 0) { \ + if (f->_field != find->_field) \ + continue; \ + } else { \ + if (f->_field == 0 || find->_field % f->_field) \ + continue; \ + } \ + } + + SLIST_FOREACH(f, list, fp_next) { + if (f->fp_tcpopts != find->fp_tcpopts || + f->fp_optcnt != find->fp_optcnt || + f->fp_ttl < find->fp_ttl || + f->fp_ttl - find->fp_ttl > ttldiff || + (f->fp_flags & (PF_OSFP_DF|PF_OSFP_TS0)) != + (find->fp_flags & (PF_OSFP_DF|PF_OSFP_TS0))) + continue; + + MATCH_INT(PF_OSFP_PSIZE_MOD, PF_OSFP_PSIZE_DC, fp_psize) + MATCH_INT(PF_OSFP_MSS_MOD, PF_OSFP_MSS_DC, fp_mss) + MATCH_INT(PF_OSFP_WSCALE_MOD, PF_OSFP_WSCALE_DC, fp_wscale) + if ((f->fp_flags & PF_OSFP_WSIZE_DC) == 0) { + if (f->fp_flags & PF_OSFP_WSIZE_MSS) { + if (find->fp_mss == 0) + continue; + +/* Some "smart" NAT devices and DSL routers will tweak the MSS size and + * will set it to whatever is suitable for the link type. + */ +#define SMART_MSS 1460 + if ((find->fp_wsize % find->fp_mss || + find->fp_wsize / find->fp_mss != + f->fp_wsize) && + (find->fp_wsize % SMART_MSS || + find->fp_wsize / SMART_MSS != + f->fp_wsize)) + continue; + } else if (f->fp_flags & PF_OSFP_WSIZE_MTU) { + if (find->fp_mss == 0) + continue; + +#define MTUOFF (sizeof(struct ip) + sizeof(struct tcphdr)) +#define SMART_MTU (SMART_MSS + MTUOFF) + if ((find->fp_wsize % (find->fp_mss + MTUOFF) || + find->fp_wsize / (find->fp_mss + MTUOFF) != + f->fp_wsize) && + (find->fp_wsize % SMART_MTU || + find->fp_wsize / SMART_MTU != + f->fp_wsize)) + continue; + } else if (f->fp_flags & PF_OSFP_WSIZE_MOD) { + if (f->fp_wsize == 0 || find->fp_wsize % + f->fp_wsize) + continue; + } else { + if (f->fp_wsize != find->fp_wsize) + continue; + } + } + return (f); + } + + return (NULL); +} + +/* Find an exact fingerprint in the list */ +struct pf_os_fingerprint * +pf_osfp_find_exact(struct pf_osfp_list *list, struct pf_os_fingerprint *find) +{ + struct pf_os_fingerprint *f; + + SLIST_FOREACH(f, list, fp_next) { + if (f->fp_tcpopts == find->fp_tcpopts && + f->fp_wsize == find->fp_wsize && + f->fp_psize == find->fp_psize && + f->fp_mss == find->fp_mss && + f->fp_flags == find->fp_flags && + f->fp_optcnt == find->fp_optcnt && + f->fp_wscale == find->fp_wscale && + f->fp_ttl == find->fp_ttl) + return (f); + } + + return (NULL); +} + +/* Insert a fingerprint into the list */ +void +pf_osfp_insert(struct pf_osfp_list *list, struct pf_os_fingerprint *ins) +{ + struct pf_os_fingerprint *f, *prev = NULL; + + /* XXX need to go semi tree based. can key on tcp options */ + + SLIST_FOREACH(f, list, fp_next) + prev = f; + if (prev) + SLIST_INSERT_AFTER(prev, ins, fp_next); + else + SLIST_INSERT_HEAD(list, ins, fp_next); +} + +/* Fill a fingerprint by its number (from an ioctl) */ +int +pf_osfp_get(struct pf_osfp_ioctl *fpioc) +{ + struct pf_os_fingerprint *fp; + struct pf_osfp_entry *entry; + int num = fpioc->fp_getnum; + int i = 0; + + + memset(fpioc, 0, sizeof(*fpioc)); + SLIST_FOREACH(fp, &pf_osfp_list, fp_next) { + SLIST_FOREACH(entry, &fp->fp_oses, fp_entry) { + if (i++ == num) { + fpioc->fp_mss = fp->fp_mss; + fpioc->fp_wsize = fp->fp_wsize; + fpioc->fp_flags = fp->fp_flags; + fpioc->fp_psize = fp->fp_psize; + fpioc->fp_ttl = fp->fp_ttl; + fpioc->fp_wscale = fp->fp_wscale; + fpioc->fp_getnum = num; + memcpy(&fpioc->fp_os, entry, + sizeof(fpioc->fp_os)); + return (0); + } + } + } + + return (EBUSY); +} + + +/* Validate that each signature is reachable */ +struct pf_os_fingerprint * +pf_osfp_validate(void) +{ + struct pf_os_fingerprint *f, *f2, find; + + SLIST_FOREACH(f, &pf_osfp_list, fp_next) { + memcpy(&find, f, sizeof(find)); + + /* We do a few MSS/th_win percolations to make things unique */ + if (find.fp_mss == 0) + find.fp_mss = 128; + if (f->fp_flags & PF_OSFP_WSIZE_MSS) + find.fp_wsize *= find.fp_mss, 1; + else if (f->fp_flags & PF_OSFP_WSIZE_MTU) + find.fp_wsize *= (find.fp_mss + 40); + else if (f->fp_flags & PF_OSFP_WSIZE_MOD) + find.fp_wsize *= 2; + if (f != (f2 = pf_osfp_find(&pf_osfp_list, &find, 0))) { + if (f2) + printf("Found \"%s %s %s\" instead of " + "\"%s %s %s\"\n", + SLIST_FIRST(&f2->fp_oses)->fp_class_nm, + SLIST_FIRST(&f2->fp_oses)->fp_version_nm, + SLIST_FIRST(&f2->fp_oses)->fp_subtype_nm, + SLIST_FIRST(&f->fp_oses)->fp_class_nm, + SLIST_FIRST(&f->fp_oses)->fp_version_nm, + SLIST_FIRST(&f->fp_oses)->fp_subtype_nm); + else + printf("Couldn't find \"%s %s %s\"\n", + SLIST_FIRST(&f->fp_oses)->fp_class_nm, + SLIST_FIRST(&f->fp_oses)->fp_version_nm, + SLIST_FIRST(&f->fp_oses)->fp_subtype_nm); + return (f); + } + } + return (NULL); +} |