ip_options.rar_FIX

/* * INET An implementation of the TCP/IP protocol suite for the LINUX * operating system. INET is implemented using the BSD Socket * interface as the means of communication with the user level. * * The options processing module for ip.c * * Authors: A.N.Kuznetsov * */ #define pr_fmt(fmt) "IPv4: " fmt #include <linux/capability.h> #include <linux/module.h> #include <linux/slab.h> #include <linux/types.h> #include <asm/uaccess.h> #include <asm/unaligned.h> #include <linux/skbuff.h> #include <linux/ip.h> #include <linux/icmp.h> #include <linux/netdevice.h> #include <linux/rtnetlink.h> #include <net/sock.h> #include <net/ip.h> #include <net/icmp.h> #include <net/route.h> #include <net/cipso_ipv4.h> #include <net/ip_fib.h> /* * Write options to IP header, record destination address to * source route option, address of outgoing interface * (we should already know it, so that this function is allowed be * called only after routing decision) and timestamp, * if we originate this datagram. * * daddr is real destination address, next hop is recorded in IP header. * saddr is address of outgoing interface. */ void ip_options_build(struct sk_buff *skb, struct ip_options *opt, __be32 daddr, struct rtable *rt, int is_frag) { unsigned char *iph = skb_network_header(skb); memcpy(&(IPCB(skb)->opt), opt, sizeof(struct ip_options)); memcpy(iph+sizeof(struct iphdr), opt->__data, opt->optlen); opt = &(IPCB(skb)->opt); if (opt->srr) memcpy(iph+opt->srr+iph[opt->srr+1]-4, &daddr, 4); if (!is_frag) { if (opt->rr_needaddr) ip_rt_get_source(iph+opt->rr+iph[opt->rr+2]-5, skb, rt); if (opt->ts_needaddr) ip_rt_get_source(iph+opt->ts+iph[opt->ts+2]-9, skb, rt); if (opt->ts_needtime) { struct timespec tv; __be32 midtime; getnstimeofday(&tv); midtime = htonl((tv.tv_sec % 86400) * MSEC_PER_SEC + tv.tv_nsec / NSEC_PER_MSEC); memcpy(iph+opt->ts+iph[opt->ts+2]-5, &midtime, 4); } return; } if (opt->rr) { memset(iph+opt->rr, IPOPT_NOP, iph[opt->rr+1]); opt->rr = 0; opt->rr_needaddr = 0; } if (opt->ts) { memset(iph+opt->ts, IPOPT_NOP, iph[opt->ts+1]); opt->ts = 0; opt->ts_needaddr = opt->ts_needtime = 0; } } /* * Provided (sopt, skb) points to received options, * build in dopt compiled option set appropriate for answering. * i.e. invert SRR option, copy anothers, * and grab room in RR/TS options. * * NOTE: dopt cannot point to skb. */ int __ip_options_echo(struct ip_options *dopt, struct sk_buff *skb, const struct ip_options *sopt) { unsigned char *sptr, *dptr; int soffset, doffset; int optlen; memset(dopt, 0, sizeof(struct ip_options)); if (sopt->optlen == 0) return 0; sptr = skb_network_header(skb); dptr = dopt->__data; if (sopt->rr) { optlen = sptr[sopt->rr+1]; soffset = sptr[sopt->rr+2]; dopt->rr = dopt->optlen + sizeof(struct iphdr); memcpy(dptr, sptr+sopt->rr, optlen); if (sopt->rr_needaddr && soffset <= optlen) { if (soffset + 3 > optlen) return -EINVAL; dptr[2] = soffset + 4; dopt->rr_needaddr = 1; } dptr += optlen; dopt->optlen += optlen; } if (sopt->ts) { optlen = sptr[sopt->ts+1]; soffset = sptr[sopt->ts+2]; dopt->ts = dopt->optlen + sizeof(struct iphdr); memcpy(dptr, sptr+sopt->ts, optlen); if (soffset <= optlen) { if (sopt->ts_needaddr) { if (soffset + 3 > optlen) return -EINVAL; dopt->ts_needaddr = 1; soffset += 4; } if (sopt->ts_needtime) { if (soffset + 3 > optlen) return -EINVAL; if ((dptr[3]&0xF) != IPOPT_TS_PRESPEC) { dopt->ts_needtime = 1; soffset += 4; } else { dopt->ts_needtime = 0; if (soffset + 7 <= optlen) { __be32 addr; memcpy(&addr, dptr+soffset-1, 4); if (inet_addr_type(dev_net(skb_dst(skb)->dev), addr) != RTN_UNICAST) { dopt->ts_needtime = 1; soffset += 8; } } } } dptr[2] = soffset; } dptr += optlen; dopt->optlen += optlen; } if (sopt->srr) { unsigned char *start = sptr+sopt->srr; __be32 faddr; optlen = start[1]; soffset = start[2]; doffset = 0; if (soffset > optlen) soffset = optlen + 1; soffset -= 4; if (soffset > 3) { memcpy(&faddr, &start[soffset-1], 4); for (soffset -= 4, doffset = 4; soffset > 3; soffset -= 4, doffset += 4) memcpy(&dptr[doffset-1], &start[soffset-1], 4); /* * RFC1812 requires to fix illegal source routes. */ if (memcmp(&ip_hdr(skb)->saddr, &start[soffset + 3], 4) == 0) doffset -= 4; } if (doffset > 3) { __be32 daddr = fib_compute_spec_dst(skb); memcpy(&start[doffset-1], &daddr, 4); dopt->faddr = faddr; dptr[0] = start[0]; dptr[1] = doffset+3; dptr[2] = 4; dptr += doffset+3; dopt->srr = dopt->optlen + sizeof(struct iphdr); dopt->optlen += doffset+3; dopt->is_strictroute = sopt->is_strictroute; } } if (sopt->cipso) { optlen = sptr[sopt->cipso+1]; dopt->cipso = dopt->optlen+sizeof(struct iphdr); memcpy(dptr, sptr+sopt->cipso, optlen); dptr += optlen; dopt->optlen += optlen; } while (dopt->optlen & 3) { *dptr++ = IPOPT_END; dopt->optlen++; } return 0; } /* * Options "fragmenting", just fill options not * allowed in fragments with NOOPs. * Simple and stupid 8), but the most efficient way. */ void ip_options_fragment(struct sk_buff *skb) { unsigned char *optptr = skb_network_header(skb) + sizeof(struct iphdr); struct ip_options *opt = &(IPCB(skb)->opt); int l = opt->optlen; int optlen; while (l > 0) { switch (*optptr) { case IPOPT_END: return; case IPOPT_NOOP: l--; optptr++; continue; } optlen = optptr[1]; if (optlen < 2 || optlen > l) return; if (!IPOPT_COPIED(*optptr)) memset(optptr, IPOPT_NOOP, optlen); l -= optlen; optptr += optlen; } opt->ts = 0; opt->rr = 0; opt->rr_needaddr = 0; opt->ts_needaddr = 0; opt->ts_needtime = 0; } /* helper used by ip_options_compile() to call fib_compute_spec_dst() * at most one time. */ static void spec_dst_fill(__be32 *spec_dst, struct sk_buff *skb) { if (*spec_dst == htonl(INADDR_ANY)) *spec_dst = fib_compute_spec_dst(skb); } /* * Verify options and fill pointers in struct options. * Caller should clear *opt, and set opt->data. * If opt == NULL, then skb->data should point to IP header. */ int ip_options_compile(struct net *net, struct ip_options *opt, struct sk_buff *skb) { __be32 spec_dst = htonl(INADDR_ANY); unsigned char *pp_ptr = NULL; struct rtable *rt = NULL; unsigned char *optptr; unsigned char *iph; int optlen, l; if (skb != NULL) { rt = skb_rtable(skb); optptr = (unsigned char *)&(ip_hdr(skb)[1]); } else optptr = opt->__data; iph = optptr - sizeof(struct iphdr); for (l = opt->optlen; l > 0; ) { switch (*optptr) { case IPOPT_END: for (optptr++, l--; l > 0; optptr++, l--) { if (*optptr != IPOPT_END) { *optptr = IPOPT_END; opt->is_changed = 1; } } goto eol; case IPOPT_NOOP: l--; optptr++; continue; } if (unlikely(l < 2)) { pp_ptr = optptr; goto error; } optlen = optptr[1]; if (optlen < 2 || optlen > l) { pp_ptr = optptr; goto error; } switch (*optptr) { case IPOPT_SSRR: case IPOPT_LSRR: if (optlen < 3) { pp_ptr = optptr + 1; goto error; } if (optptr[2] < 4) { pp_ptr = optptr + 2; goto error; } /* NB: cf RFC-1812 5.2.4.1 */ if (opt->srr) { pp_ptr = optptr; goto error; } if (!skb) { if (optptr[2] != 4 || optlen < 7 || ((optlen-3) & 3)) { pp_ptr = optptr + 1; goto error; } memcpy(&opt->faddr, &optptr[3], 4); if (optlen > 7) memmove(&optptr[3], &optptr[7], optlen-7); } opt->is_strictroute = (optptr[0] == IPOPT_SSRR); opt->srr = optptr - iph; break; case IPOPT_RR: if (opt->rr) { pp_ptr = optptr; goto error; } if (optlen < 3) { pp_ptr = optptr + 1; goto error; } if (optptr[2] < 4) { pp_ptr = optptr + 2; goto