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-rw-r--r--net/ipv6/exthdrs.c1356
1 files changed, 1356 insertions, 0 deletions
diff --git a/net/ipv6/exthdrs.c b/net/ipv6/exthdrs.c
new file mode 100644
index 000000000..cdad9019c
--- /dev/null
+++ b/net/ipv6/exthdrs.c
@@ -0,0 +1,1356 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Extension Header handling for IPv6
+ * Linux INET6 implementation
+ *
+ * Authors:
+ * Pedro Roque <roque@di.fc.ul.pt>
+ * Andi Kleen <ak@muc.de>
+ * Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
+ */
+
+/* Changes:
+ * yoshfuji : ensure not to overrun while parsing
+ * tlv options.
+ * Mitsuru KANDA @USAGI and: Remove ipv6_parse_exthdrs().
+ * YOSHIFUJI Hideaki @USAGI Register inbound extension header
+ * handlers as inet6_protocol{}.
+ */
+
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/socket.h>
+#include <linux/sockios.h>
+#include <linux/net.h>
+#include <linux/netdevice.h>
+#include <linux/in6.h>
+#include <linux/icmpv6.h>
+#include <linux/slab.h>
+#include <linux/export.h>
+
+#include <net/dst.h>
+#include <net/sock.h>
+#include <net/snmp.h>
+
+#include <net/ipv6.h>
+#include <net/protocol.h>
+#include <net/transp_v6.h>
+#include <net/rawv6.h>
+#include <net/ndisc.h>
+#include <net/ip6_route.h>
+#include <net/addrconf.h>
+#include <net/calipso.h>
+#if IS_ENABLED(CONFIG_IPV6_MIP6)
+#include <net/xfrm.h>
+#endif
+#include <linux/seg6.h>
+#include <net/seg6.h>
+#ifdef CONFIG_IPV6_SEG6_HMAC
+#include <net/seg6_hmac.h>
+#endif
+#include <net/rpl.h>
+
+#include <linux/uaccess.h>
+
+/*
+ * Parsing tlv encoded headers.
+ *
+ * Parsing function "func" returns true, if parsing succeed
+ * and false, if it failed.
+ * It MUST NOT touch skb->h.
+ */
+
+struct tlvtype_proc {
+ int type;
+ bool (*func)(struct sk_buff *skb, int offset);
+};
+
+/*********************
+ Generic functions
+ *********************/
+
+/* An unknown option is detected, decide what to do */
+
+static bool ip6_tlvopt_unknown(struct sk_buff *skb, int optoff,
+ bool disallow_unknowns)
+{
+ if (disallow_unknowns) {
+ /* If unknown TLVs are disallowed by configuration
+ * then always silently drop packet. Note this also
+ * means no ICMP parameter problem is sent which
+ * could be a good property to mitigate a reflection DOS
+ * attack.
+ */
+
+ goto drop;
+ }
+
+ switch ((skb_network_header(skb)[optoff] & 0xC0) >> 6) {
+ case 0: /* ignore */
+ return true;
+
+ case 1: /* drop packet */
+ break;
+
+ case 3: /* Send ICMP if not a multicast address and drop packet */
+ /* Actually, it is redundant check. icmp_send
+ will recheck in any case.
+ */
+ if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr))
+ break;
+ fallthrough;
+ case 2: /* send ICMP PARM PROB regardless and drop packet */
+ icmpv6_param_prob(skb, ICMPV6_UNK_OPTION, optoff);
+ return false;
+ }
+
+drop:
+ kfree_skb(skb);
+ return false;
+}
+
+/* Parse tlv encoded option header (hop-by-hop or destination) */
+
+static bool ip6_parse_tlv(const struct tlvtype_proc *procs,
+ struct sk_buff *skb,
+ int max_count)
+{
+ int len = (skb_transport_header(skb)[1] + 1) << 3;
+ const unsigned char *nh = skb_network_header(skb);
+ int off = skb_network_header_len(skb);
+ const struct tlvtype_proc *curr;
+ bool disallow_unknowns = false;
+ int tlv_count = 0;
+ int padlen = 0;
+
+ if (unlikely(max_count < 0)) {
+ disallow_unknowns = true;
+ max_count = -max_count;
+ }
+
+ if (skb_transport_offset(skb) + len > skb_headlen(skb))
+ goto bad;
+
+ off += 2;
+ len -= 2;
+
+ while (len > 0) {
+ int optlen, i;
+
+ if (nh[off] == IPV6_TLV_PAD1) {
+ padlen++;
+ if (padlen > 7)
+ goto bad;
+ off++;
+ len--;
+ continue;
+ }
+ if (len < 2)
+ goto bad;
+ optlen = nh[off + 1] + 2;
+ if (optlen > len)
+ goto bad;
+
+ if (nh[off] == IPV6_TLV_PADN) {
+ /* RFC 2460 states that the purpose of PadN is
+ * to align the containing header to multiples
+ * of 8. 7 is therefore the highest valid value.
+ * See also RFC 4942, Section 2.1.9.5.
+ */
+ padlen += optlen;
+ if (padlen > 7)
+ goto bad;
+ /* RFC 4942 recommends receiving hosts to
+ * actively check PadN payload to contain
+ * only zeroes.
+ */
+ for (i = 2; i < optlen; i++) {
+ if (nh[off + i] != 0)
+ goto bad;
+ }
+ } else {
+ tlv_count++;
+ if (tlv_count > max_count)
+ goto bad;
+
+ for (curr = procs; curr->type >= 0; curr++) {
+ if (curr->type == nh[off]) {
+ /* type specific length/alignment
+ checks will be performed in the
+ func(). */
+ if (curr->func(skb, off) == false)
+ return false;
+ break;
+ }
+ }
+ if (curr->type < 0 &&
+ !ip6_tlvopt_unknown(skb, off, disallow_unknowns))
+ return false;
+
+ padlen = 0;
+ }
+ off += optlen;
+ len -= optlen;
+ }
+
+ if (len == 0)
+ return true;
+bad:
+ kfree_skb(skb);
+ return false;
+}
+
+/*****************************
+ Destination options header.
+ *****************************/
+
+#if IS_ENABLED(CONFIG_IPV6_MIP6)
+static bool ipv6_dest_hao(struct sk_buff *skb, int optoff)
+{
+ struct ipv6_destopt_hao *hao;
+ struct inet6_skb_parm *opt = IP6CB(skb);
+ struct ipv6hdr *ipv6h = ipv6_hdr(skb);
+ int ret;
+
+ if (opt->dsthao) {
+ net_dbg_ratelimited("hao duplicated\n");
+ goto discard;
+ }
+ opt->dsthao = opt->dst1;
+ opt->dst1 = 0;
+
+ hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) + optoff);
+
+ if (hao->length != 16) {
+ net_dbg_ratelimited("hao invalid option length = %d\n",
+ hao->length);
+ goto discard;
+ }
+
+ if (!(ipv6_addr_type(&hao->addr) & IPV6_ADDR_UNICAST)) {
+ net_dbg_ratelimited("hao is not an unicast addr: %pI6\n",
+ &hao->addr);
+ goto discard;
+ }
+
+ ret = xfrm6_input_addr(skb, (xfrm_address_t *)&ipv6h->daddr,
+ (xfrm_address_t *)&hao->addr, IPPROTO_DSTOPTS);
+ if (unlikely(ret < 0))
+ goto discard;
+
+ if (skb_cloned(skb)) {
+ if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
+ goto discard;
+
+ /* update all variable using below by copied skbuff */
+ hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) +
+ optoff);
+ ipv6h = ipv6_hdr(skb);
+ }
+
+ if (skb->ip_summed == CHECKSUM_COMPLETE)
+ skb->ip_summed = CHECKSUM_NONE;
+
+ swap(ipv6h->saddr, hao->addr);
+
+ if (skb->tstamp == 0)
+ __net_timestamp(skb);
+
+ return true;
+
+ discard:
+ kfree_skb(skb);
+ return false;
+}
+#endif
+
+static const struct tlvtype_proc tlvprocdestopt_lst[] = {
+#if IS_ENABLED(CONFIG_IPV6_MIP6)
+ {
+ .type = IPV6_TLV_HAO,
+ .func = ipv6_dest_hao,
+ },
+#endif
+ {-1, NULL}
+};
+
+static int ipv6_destopt_rcv(struct sk_buff *skb)
+{
+ struct inet6_dev *idev = __in6_dev_get(skb->dev);
+ struct inet6_skb_parm *opt = IP6CB(skb);
+#if IS_ENABLED(CONFIG_IPV6_MIP6)
+ __u16 dstbuf;
+#endif
+ struct dst_entry *dst = skb_dst(skb);
+ struct net *net = dev_net(skb->dev);
+ int extlen;
+
+ if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
+ !pskb_may_pull(skb, (skb_transport_offset(skb) +
+ ((skb_transport_header(skb)[1] + 1) << 3)))) {
+ __IP6_INC_STATS(dev_net(dst->dev), idev,
+ IPSTATS_MIB_INHDRERRORS);
+fail_and_free:
+ kfree_skb(skb);
+ return -1;
+ }
+
+ extlen = (skb_transport_header(skb)[1] + 1) << 3;
+ if (extlen > net->ipv6.sysctl.max_dst_opts_len)
+ goto fail_and_free;
+
+ opt->lastopt = opt->dst1 = skb_network_header_len(skb);
+#if IS_ENABLED(CONFIG_IPV6_MIP6)
+ dstbuf = opt->dst1;
+#endif
+
+ if (ip6_parse_tlv(tlvprocdestopt_lst, skb,
+ net->ipv6.sysctl.max_dst_opts_cnt)) {
+ skb->transport_header += extlen;
+ opt = IP6CB(skb);
+#if IS_ENABLED(CONFIG_IPV6_MIP6)
+ opt->nhoff = dstbuf;
+#else
+ opt->nhoff = opt->dst1;
+#endif
+ return 1;
+ }
+
+ __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
+ return -1;
+}
+
+static void seg6_update_csum(struct sk_buff *skb)
+{
+ struct ipv6_sr_hdr *hdr;
+ struct in6_addr *addr;
+ __be32 from, to;
+
+ /* srh is at transport offset and seg_left is already decremented
+ * but daddr is not yet updated with next segment
+ */
+
+ hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb);
+ addr = hdr->segments + hdr->segments_left;
+
+ hdr->segments_left++;
+ from = *(__be32 *)hdr;
+
+ hdr->segments_left--;
+ to = *(__be32 *)hdr;
+
+ /* update skb csum with diff resulting from seg_left decrement */
+
+ update_csum_diff4(skb, from, to);
+
+ /* compute csum diff between current and next segment and update */
+
+ update_csum_diff16(skb, (__be32 *)(&ipv6_hdr(skb)->daddr),
+ (__be32 *)addr);
+}
+
+static int ipv6_srh_rcv(struct sk_buff *skb)
+{
+ struct inet6_skb_parm *opt = IP6CB(skb);
+ struct net *net = dev_net(skb->dev);
+ struct ipv6_sr_hdr *hdr;
+ struct inet6_dev *idev;
+ struct in6_addr *addr;
+ int accept_seg6;
+
+ hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb);
+
+ idev = __in6_dev_get(skb->dev);
+
+ accept_seg6 = net->ipv6.devconf_all->seg6_enabled;
+ if (accept_seg6 > idev->cnf.seg6_enabled)
+ accept_seg6 = idev->cnf.seg6_enabled;
+
+ if (!accept_seg6) {
+ kfree_skb(skb);
+ return -1;
+ }
+
+#ifdef CONFIG_IPV6_SEG6_HMAC
+ if (!seg6_hmac_validate_skb(skb)) {
+ kfree_skb(skb);
+ return -1;
+ }
+#endif
+
+looped_back:
+ if (hdr->segments_left == 0) {
+ if (hdr->nexthdr == NEXTHDR_IPV6) {
+ int offset = (hdr->hdrlen + 1) << 3;
+
+ skb_postpull_rcsum(skb, skb_network_header(skb),
+ skb_network_header_len(skb));
+
+ if (!pskb_pull(skb, offset)) {
+ kfree_skb(skb);
+ return -1;
+ }
+ skb_postpull_rcsum(skb, skb_transport_header(skb),
+ offset);
+
+ skb_reset_network_header(skb);
+ skb_reset_transport_header(skb);
+ skb->encapsulation = 0;
+
+ __skb_tunnel_rx(skb, skb->dev, net);
+
+ netif_rx(skb);
+ return -1;
+ }
+
+ opt->srcrt = skb_network_header_len(skb);
+ opt->lastopt = opt->srcrt;
+ skb->transport_header += (hdr->hdrlen + 1) << 3;
+ opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
+
+ return 1;
+ }
+
+ if (hdr->segments_left >= (hdr->hdrlen >> 1)) {
+ __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
+ icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
+ ((&hdr->segments_left) -
+ skb_network_header(skb)));
+ return -1;
+ }
+
+ if (skb_cloned(skb)) {
+ if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) {
+ __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
+ IPSTATS_MIB_OUTDISCARDS);
+ kfree_skb(skb);
+ return -1;
+ }
+ }
+
+ hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb);
+
+ hdr->segments_left--;
+ addr = hdr->segments + hdr->segments_left;
+
+ skb_push(skb, sizeof(struct ipv6hdr));
+
+ if (skb->ip_summed == CHECKSUM_COMPLETE)
+ seg6_update_csum(skb);
+
+ ipv6_hdr(skb)->daddr = *addr;
+
+ skb_dst_drop(skb);
+
+ ip6_route_input(skb);
+
+ if (skb_dst(skb)->error) {
+ dst_input(skb);
+ return -1;
+ }
+
+ if (skb_dst(skb)->dev->flags & IFF_LOOPBACK) {
+ if (ipv6_hdr(skb)->hop_limit <= 1) {
+ __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
+ icmpv6_send(skb, ICMPV6_TIME_EXCEED,
+ ICMPV6_EXC_HOPLIMIT, 0);
+ kfree_skb(skb);
+ return -1;
+ }
+ ipv6_hdr(skb)->hop_limit--;
+
+ skb_pull(skb, sizeof(struct ipv6hdr));
+ goto looped_back;
+ }
+
+ dst_input(skb);
+
+ return -1;
+}
+
+static int ipv6_rpl_srh_rcv(struct sk_buff *skb)
+{
+ struct ipv6_rpl_sr_hdr *hdr, *ohdr, *chdr;
+ struct inet6_skb_parm *opt = IP6CB(skb);
+ struct net *net = dev_net(skb->dev);
+ struct inet6_dev *idev;
+ struct ipv6hdr *oldhdr;
+ struct in6_addr addr;
+ unsigned char *buf;
+ int accept_rpl_seg;
+ int i, err;
+ u64 n = 0;
+ u32 r;
+
+ idev = __in6_dev_get(skb->dev);
+
+ accept_rpl_seg = net->ipv6.devconf_all->rpl_seg_enabled;
+ if (accept_rpl_seg > idev->cnf.rpl_seg_enabled)
+ accept_rpl_seg = idev->cnf.rpl_seg_enabled;
+
+ if (!accept_rpl_seg) {
+ kfree_skb(skb);
+ return -1;
+ }
+
+looped_back:
+ hdr = (struct ipv6_rpl_sr_hdr *)skb_transport_header(skb);
+
+ if (hdr->segments_left == 0) {
+ if (hdr->nexthdr == NEXTHDR_IPV6) {
+ int offset = (hdr->hdrlen + 1) << 3;
+
+ skb_postpull_rcsum(skb, skb_network_header(skb),
+ skb_network_header_len(skb));
+
+ if (!pskb_pull(skb, offset)) {
+ kfree_skb(skb);
+ return -1;
+ }
+ skb_postpull_rcsum(skb, skb_transport_header(skb),
+ offset);
+
+ skb_reset_network_header(skb);
+ skb_reset_transport_header(skb);
+ skb->encapsulation = 0;
+
+ __skb_tunnel_rx(skb, skb->dev, net);
+
+ netif_rx(skb);
+ return -1;
+ }
+
+ opt->srcrt = skb_network_header_len(skb);
+ opt->lastopt = opt->srcrt;
+ skb->transport_header += (hdr->hdrlen + 1) << 3;
+ opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
+
+ return 1;
+ }
+
+ if (!pskb_may_pull(skb, sizeof(*hdr))) {
+ kfree_skb(skb);
+ return -1;
+ }
+
+ n = (hdr->hdrlen << 3) - hdr->pad - (16 - hdr->cmpre);
+ r = do_div(n, (16 - hdr->cmpri));
+ /* checks if calculation was without remainder and n fits into
+ * unsigned char which is segments_left field. Should not be
+ * higher than that.
+ */
+ if (r || (n + 1) > 255) {
+ kfree_skb(skb);
+ return -1;
+ }
+
+ if (hdr->segments_left > n + 1) {
+ __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
+ icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
+ ((&hdr->segments_left) -
+ skb_network_header(skb)));
+ return -1;
+ }
+
+ if (!pskb_may_pull(skb, ipv6_rpl_srh_size(n, hdr->cmpri,
+ hdr->cmpre))) {
+ kfree_skb(skb);
+ return -1;
+ }
+
+ hdr->segments_left--;
+ i = n - hdr->segments_left;
+
+ buf = kcalloc(struct_size(hdr, segments.addr, n + 2), 2, GFP_ATOMIC);
+ if (unlikely(!buf)) {
+ kfree_skb(skb);
+ return -1;
+ }
+
+ ohdr = (struct ipv6_rpl_sr_hdr *)buf;
+ ipv6_rpl_srh_decompress(ohdr, hdr, &ipv6_hdr(skb)->daddr, n);
+ chdr = (struct ipv6_rpl_sr_hdr *)(buf + ((ohdr->hdrlen + 1) << 3));
+
+ if ((ipv6_addr_type(&ipv6_hdr(skb)->daddr) & IPV6_ADDR_MULTICAST) ||
+ (ipv6_addr_type(&ohdr->rpl_segaddr[i]) & IPV6_ADDR_MULTICAST)) {
+ kfree_skb(skb);
+ kfree(buf);
+ return -1;
+ }
+
+ err = ipv6_chk_rpl_srh_loop(net, ohdr->rpl_segaddr, n + 1);
+ if (err) {
+ icmpv6_send(skb, ICMPV6_PARAMPROB, 0, 0);
+ kfree_skb(skb);
+ kfree(buf);
+ return -1;
+ }
+
+ addr = ipv6_hdr(skb)->daddr;
+ ipv6_hdr(skb)->daddr = ohdr->rpl_segaddr[i];
+ ohdr->rpl_segaddr[i] = addr;
+
+ ipv6_rpl_srh_compress(chdr, ohdr, &ipv6_hdr(skb)->daddr, n);
+
+ oldhdr = ipv6_hdr(skb);
+
+ skb_pull(skb, ((hdr->hdrlen + 1) << 3));
+ skb_postpull_rcsum(skb, oldhdr,
+ sizeof(struct ipv6hdr) + ((hdr->hdrlen + 1) << 3));
+ if (unlikely(!hdr->segments_left)) {
+ if (pskb_expand_head(skb, sizeof(struct ipv6hdr) + ((chdr->hdrlen + 1) << 3), 0,
+ GFP_ATOMIC)) {
+ __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_OUTDISCARDS);
+ kfree_skb(skb);
+ kfree(buf);
+ return -1;
+ }
+
+ oldhdr = ipv6_hdr(skb);
+ }
+ skb_push(skb, ((chdr->hdrlen + 1) << 3) + sizeof(struct ipv6hdr));
+ skb_reset_network_header(skb);
+ skb_mac_header_rebuild(skb);
+ skb_set_transport_header(skb, sizeof(struct ipv6hdr));
+
+ memmove(ipv6_hdr(skb), oldhdr, sizeof(struct ipv6hdr));
+ memcpy(skb_transport_header(skb), chdr, (chdr->hdrlen + 1) << 3);
+
+ ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
+ skb_postpush_rcsum(skb, ipv6_hdr(skb),
+ sizeof(struct ipv6hdr) + ((chdr->hdrlen + 1) << 3));
+
+ kfree(buf);
+
+ skb_dst_drop(skb);
+
+ ip6_route_input(skb);
+
+ if (skb_dst(skb)->error) {
+ dst_input(skb);
+ return -1;
+ }
+
+ if (skb_dst(skb)->dev->flags & IFF_LOOPBACK) {
+ if (ipv6_hdr(skb)->hop_limit <= 1) {
+ __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
+ icmpv6_send(skb, ICMPV6_TIME_EXCEED,
+ ICMPV6_EXC_HOPLIMIT, 0);
+ kfree_skb(skb);
+ return -1;
+ }
+ ipv6_hdr(skb)->hop_limit--;
+
+ skb_pull(skb, sizeof(struct ipv6hdr));
+ goto looped_back;
+ }
+
+ dst_input(skb);
+
+ return -1;
+}
+
+/********************************
+ Routing header.
+ ********************************/
+
+/* called with rcu_read_lock() */
+static int ipv6_rthdr_rcv(struct sk_buff *skb)
+{
+ struct inet6_dev *idev = __in6_dev_get(skb->dev);
+ struct inet6_skb_parm *opt = IP6CB(skb);
+ struct in6_addr *addr = NULL;
+ struct in6_addr daddr;
+ int n, i;
+ struct ipv6_rt_hdr *hdr;
+ struct rt0_hdr *rthdr;
+ struct net *net = dev_net(skb->dev);
+ int accept_source_route = net->ipv6.devconf_all->accept_source_route;
+
+ idev = __in6_dev_get(skb->dev);
+ if (idev && accept_source_route > idev->cnf.accept_source_route)
+ accept_source_route = idev->cnf.accept_source_route;
+
+ if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
+ !pskb_may_pull(skb, (skb_transport_offset(skb) +
+ ((skb_transport_header(skb)[1] + 1) << 3)))) {
+ __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
+ kfree_skb(skb);
+ return -1;
+ }
+
+ hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
+
+ if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) ||
+ skb->pkt_type != PACKET_HOST) {
+ __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
+ kfree_skb(skb);
+ return -1;
+ }
+
+ switch (hdr->type) {
+ case IPV6_SRCRT_TYPE_4:
+ /* segment routing */
+ return ipv6_srh_rcv(skb);
+ case IPV6_SRCRT_TYPE_3:
+ /* rpl segment routing */
+ return ipv6_rpl_srh_rcv(skb);
+ default:
+ break;
+ }
+
+looped_back:
+ if (hdr->segments_left == 0) {
+ switch (hdr->type) {
+#if IS_ENABLED(CONFIG_IPV6_MIP6)
+ case IPV6_SRCRT_TYPE_2:
+ /* Silently discard type 2 header unless it was
+ * processed by own
+ */
+ if (!addr) {
+ __IP6_INC_STATS(net, idev,
+ IPSTATS_MIB_INADDRERRORS);
+ kfree_skb(skb);
+ return -1;
+ }
+ break;
+#endif
+ default:
+ break;
+ }
+
+ opt->lastopt = opt->srcrt = skb_network_header_len(skb);
+ skb->transport_header += (hdr->hdrlen + 1) << 3;
+ opt->dst0 = opt->dst1;
+ opt->dst1 = 0;
+ opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
+ return 1;
+ }
+
+ switch (hdr->type) {
+#if IS_ENABLED(CONFIG_IPV6_MIP6)
+ case IPV6_SRCRT_TYPE_2:
+ if (accept_source_route < 0)
+ goto unknown_rh;
+ /* Silently discard invalid RTH type 2 */
+ if (hdr->hdrlen != 2 || hdr->segments_left != 1) {
+ __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
+ kfree_skb(skb);
+ return -1;
+ }
+ break;
+#endif
+ default:
+ goto unknown_rh;
+ }
+
+ /*
+ * This is the routing header forwarding algorithm from
+ * RFC 2460, page 16.
+ */
+
+ n = hdr->hdrlen >> 1;
+
+ if (hdr->segments_left > n) {
+ __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
+ icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
+ ((&hdr->segments_left) -
+ skb_network_header(skb)));
+ return -1;
+ }
+
+ /* We are about to mangle packet header. Be careful!
+ Do not damage packets queued somewhere.
+ */
+ if (skb_cloned(skb)) {
+ /* the copy is a forwarded packet */
+ if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) {
+ __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
+ IPSTATS_MIB_OUTDISCARDS);
+ kfree_skb(skb);
+ return -1;
+ }
+ hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
+ }
+
+ if (skb->ip_summed == CHECKSUM_COMPLETE)
+ skb->ip_summed = CHECKSUM_NONE;
+
+ i = n - --hdr->segments_left;
+
+ rthdr = (struct rt0_hdr *) hdr;
+ addr = rthdr->addr;
+ addr += i - 1;
+
+ switch (hdr->type) {
+#if IS_ENABLED(CONFIG_IPV6_MIP6)
+ case IPV6_SRCRT_TYPE_2:
+ if (xfrm6_input_addr(skb, (xfrm_address_t *)addr,
+ (xfrm_address_t *)&ipv6_hdr(skb)->saddr,
+ IPPROTO_ROUTING) < 0) {
+ __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
+ kfree_skb(skb);
+ return -1;
+ }
+ if (!ipv6_chk_home_addr(dev_net(skb_dst(skb)->dev), addr)) {
+ __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
+ kfree_skb(skb);
+ return -1;
+ }
+ break;
+#endif
+ default:
+ break;
+ }
+
+ if (ipv6_addr_is_multicast(addr)) {
+ __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
+ kfree_skb(skb);
+ return -1;
+ }
+
+ daddr = *addr;
+ *addr = ipv6_hdr(skb)->daddr;
+ ipv6_hdr(skb)->daddr = daddr;
+
+ skb_dst_drop(skb);
+ ip6_route_input(skb);
+ if (skb_dst(skb)->error) {
+ skb_push(skb, skb->data - skb_network_header(skb));
+ dst_input(skb);
+ return -1;
+ }
+
+ if (skb_dst(skb)->dev->flags&IFF_LOOPBACK) {
+ if (ipv6_hdr(skb)->hop_limit <= 1) {
+ __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
+ icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT,
+ 0);
+ kfree_skb(skb);
+ return -1;
+ }
+ ipv6_hdr(skb)->hop_limit--;
+ goto looped_back;
+ }
+
+ skb_push(skb, skb->data - skb_network_header(skb));
+ dst_input(skb);
+ return -1;
+
+unknown_rh:
+ __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
+ icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
+ (&hdr->type) - skb_network_header(skb));
+ return -1;
+}
+
+static const struct inet6_protocol rthdr_protocol = {
+ .handler = ipv6_rthdr_rcv,
+ .flags = INET6_PROTO_NOPOLICY,
+};
+
+static const struct inet6_protocol destopt_protocol = {
+ .handler = ipv6_destopt_rcv,
+ .flags = INET6_PROTO_NOPOLICY,
+};
+
+static const struct inet6_protocol nodata_protocol = {
+ .handler = dst_discard,
+ .flags = INET6_PROTO_NOPOLICY,
+};
+
+int __init ipv6_exthdrs_init(void)
+{
+ int ret;
+
+ ret = inet6_add_protocol(&rthdr_protocol, IPPROTO_ROUTING);
+ if (ret)
+ goto out;
+
+ ret = inet6_add_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
+ if (ret)
+ goto out_rthdr;
+
+ ret = inet6_add_protocol(&nodata_protocol, IPPROTO_NONE);
+ if (ret)
+ goto out_destopt;
+
+out:
+ return ret;
+out_destopt:
+ inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
+out_rthdr:
+ inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
+ goto out;
+};
+
+void ipv6_exthdrs_exit(void)
+{
+ inet6_del_protocol(&nodata_protocol, IPPROTO_NONE);
+ inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
+ inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
+}
+
+/**********************************
+ Hop-by-hop options.
+ **********************************/
+
+/*
+ * Note: we cannot rely on skb_dst(skb) before we assign it in ip6_route_input().
+ */
+static inline struct inet6_dev *ipv6_skb_idev(struct sk_buff *skb)
+{
+ return skb_dst(skb) ? ip6_dst_idev(skb_dst(skb)) : __in6_dev_get(skb->dev);
+}
+
+static inline struct net *ipv6_skb_net(struct sk_buff *skb)
+{
+ return skb_dst(skb) ? dev_net(skb_dst(skb)->dev) : dev_net(skb->dev);
+}
+
+/* Router Alert as of RFC 2711 */
+
+static bool ipv6_hop_ra(struct sk_buff *skb, int optoff)
+{
+ const unsigned char *nh = skb_network_header(skb);
+
+ if (nh[optoff + 1] == 2) {
+ IP6CB(skb)->flags |= IP6SKB_ROUTERALERT;
+ memcpy(&IP6CB(skb)->ra, nh + optoff + 2, sizeof(IP6CB(skb)->ra));
+ return true;
+ }
+ net_dbg_ratelimited("ipv6_hop_ra: wrong RA length %d\n",
+ nh[optoff + 1]);
+ kfree_skb(skb);
+ return false;
+}
+
+/* Jumbo payload */
+
+static bool ipv6_hop_jumbo(struct sk_buff *skb, int optoff)
+{
+ const unsigned char *nh = skb_network_header(skb);
+ struct inet6_dev *idev = __in6_dev_get_safely(skb->dev);
+ struct net *net = ipv6_skb_net(skb);
+ u32 pkt_len;
+
+ if (nh[optoff + 1] != 4 || (optoff & 3) != 2) {
+ net_dbg_ratelimited("ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n",
+ nh[optoff+1]);
+ __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
+ goto drop;
+ }
+
+ pkt_len = ntohl(*(__be32 *)(nh + optoff + 2));
+ if (pkt_len <= IPV6_MAXPLEN) {
+ __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
+ icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff+2);
+ return false;
+ }
+ if (ipv6_hdr(skb)->payload_len) {
+ __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
+ icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff);
+ return false;
+ }
+
+ if (pkt_len > skb->len - sizeof(struct ipv6hdr)) {
+ __IP6_INC_STATS(net, idev, IPSTATS_MIB_INTRUNCATEDPKTS);
+ goto drop;
+ }
+
+ if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr)))
+ goto drop;
+
+ IP6CB(skb)->flags |= IP6SKB_JUMBOGRAM;
+ return true;
+
+drop:
+ kfree_skb(skb);
+ return false;
+}
+
+/* CALIPSO RFC 5570 */
+
+static bool ipv6_hop_calipso(struct sk_buff *skb, int optoff)
+{
+ const unsigned char *nh = skb_network_header(skb);
+
+ if (nh[optoff + 1] < 8)
+ goto drop;
+
+ if (nh[optoff + 6] * 4 + 8 > nh[optoff + 1])
+ goto drop;
+
+ if (!calipso_validate(skb, nh + optoff))
+ goto drop;
+
+ return true;
+
+drop:
+ kfree_skb(skb);
+ return false;
+}
+
+static const struct tlvtype_proc tlvprochopopt_lst[] = {
+ {
+ .type = IPV6_TLV_ROUTERALERT,
+ .func = ipv6_hop_ra,
+ },
+ {
+ .type = IPV6_TLV_JUMBO,
+ .func = ipv6_hop_jumbo,
+ },
+ {
+ .type = IPV6_TLV_CALIPSO,
+ .func = ipv6_hop_calipso,
+ },
+ { -1, }
+};
+
+int ipv6_parse_hopopts(struct sk_buff *skb)
+{
+ struct inet6_skb_parm *opt = IP6CB(skb);
+ struct net *net = dev_net(skb->dev);
+ int extlen;
+
+ /*
+ * skb_network_header(skb) is equal to skb->data, and
+ * skb_network_header_len(skb) is always equal to
+ * sizeof(struct ipv6hdr) by definition of
+ * hop-by-hop options.
+ */
+ if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + 8) ||
+ !pskb_may_pull(skb, (sizeof(struct ipv6hdr) +
+ ((skb_transport_header(skb)[1] + 1) << 3)))) {
+fail_and_free:
+ kfree_skb(skb);
+ return -1;
+ }
+
+ extlen = (skb_transport_header(skb)[1] + 1) << 3;
+ if (extlen > net->ipv6.sysctl.max_hbh_opts_len)
+ goto fail_and_free;
+
+ opt->flags |= IP6SKB_HOPBYHOP;
+ if (ip6_parse_tlv(tlvprochopopt_lst, skb,
+ net->ipv6.sysctl.max_hbh_opts_cnt)) {
+ skb->transport_header += extlen;
+ opt = IP6CB(skb);
+ opt->nhoff = sizeof(struct ipv6hdr);
+ return 1;
+ }
+ return -1;
+}
+
+/*
+ * Creating outbound headers.
+ *
+ * "build" functions work when skb is filled from head to tail (datagram)
+ * "push" functions work when headers are added from tail to head (tcp)
+ *
+ * In both cases we assume, that caller reserved enough room
+ * for headers.
+ */
+
+static void ipv6_push_rthdr0(struct sk_buff *skb, u8 *proto,
+ struct ipv6_rt_hdr *opt,
+ struct in6_addr **addr_p, struct in6_addr *saddr)
+{
+ struct rt0_hdr *phdr, *ihdr;
+ int hops;
+
+ ihdr = (struct rt0_hdr *) opt;
+
+ phdr = skb_push(skb, (ihdr->rt_hdr.hdrlen + 1) << 3);
+ memcpy(phdr, ihdr, sizeof(struct rt0_hdr));
+
+ hops = ihdr->rt_hdr.hdrlen >> 1;
+
+ if (hops > 1)
+ memcpy(phdr->addr, ihdr->addr + 1,
+ (hops - 1) * sizeof(struct in6_addr));
+
+ phdr->addr[hops - 1] = **addr_p;
+ *addr_p = ihdr->addr;
+
+ phdr->rt_hdr.nexthdr = *proto;
+ *proto = NEXTHDR_ROUTING;
+}
+
+static void ipv6_push_rthdr4(struct sk_buff *skb, u8 *proto,
+ struct ipv6_rt_hdr *opt,
+ struct in6_addr **addr_p, struct in6_addr *saddr)
+{
+ struct ipv6_sr_hdr *sr_phdr, *sr_ihdr;
+ int plen, hops;
+
+ sr_ihdr = (struct ipv6_sr_hdr *)opt;
+ plen = (sr_ihdr->hdrlen + 1) << 3;
+
+ sr_phdr = skb_push(skb, plen);
+ memcpy(sr_phdr, sr_ihdr, sizeof(struct ipv6_sr_hdr));
+
+ hops = sr_ihdr->first_segment + 1;
+ memcpy(sr_phdr->segments + 1, sr_ihdr->segments + 1,
+ (hops - 1) * sizeof(struct in6_addr));
+
+ sr_phdr->segments[0] = **addr_p;
+ *addr_p = &sr_ihdr->segments[sr_ihdr->segments_left];
+
+ if (sr_ihdr->hdrlen > hops * 2) {
+ int tlvs_offset, tlvs_length;
+
+ tlvs_offset = (1 + hops * 2) << 3;
+ tlvs_length = (sr_ihdr->hdrlen - hops * 2) << 3;
+ memcpy((char *)sr_phdr + tlvs_offset,
+ (char *)sr_ihdr + tlvs_offset, tlvs_length);
+ }
+
+#ifdef CONFIG_IPV6_SEG6_HMAC
+ if (sr_has_hmac(sr_phdr)) {
+ struct net *net = NULL;
+
+ if (skb->dev)
+ net = dev_net(skb->dev);
+ else if (skb->sk)
+ net = sock_net(skb->sk);
+
+ WARN_ON(!net);
+
+ if (net)
+ seg6_push_hmac(net, saddr, sr_phdr);
+ }
+#endif
+
+ sr_phdr->nexthdr = *proto;
+ *proto = NEXTHDR_ROUTING;
+}
+
+static void ipv6_push_rthdr(struct sk_buff *skb, u8 *proto,
+ struct ipv6_rt_hdr *opt,
+ struct in6_addr **addr_p, struct in6_addr *saddr)
+{
+ switch (opt->type) {
+ case IPV6_SRCRT_TYPE_0:
+ case IPV6_SRCRT_STRICT:
+ case IPV6_SRCRT_TYPE_2:
+ ipv6_push_rthdr0(skb, proto, opt, addr_p, saddr);
+ break;
+ case IPV6_SRCRT_TYPE_4:
+ ipv6_push_rthdr4(skb, proto, opt, addr_p, saddr);
+ break;
+ default:
+ break;
+ }
+}
+
+static void ipv6_push_exthdr(struct sk_buff *skb, u8 *proto, u8 type, struct ipv6_opt_hdr *opt)
+{
+ struct ipv6_opt_hdr *h = skb_push(skb, ipv6_optlen(opt));
+
+ memcpy(h, opt, ipv6_optlen(opt));
+ h->nexthdr = *proto;
+ *proto = type;
+}
+
+void ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt,
+ u8 *proto,
+ struct in6_addr **daddr, struct in6_addr *saddr)
+{
+ if (opt->srcrt) {
+ ipv6_push_rthdr(skb, proto, opt->srcrt, daddr, saddr);
+ /*
+ * IPV6_RTHDRDSTOPTS is ignored
+ * unless IPV6_RTHDR is set (RFC3542).
+ */
+ if (opt->dst0opt)
+ ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst0opt);
+ }
+ if (opt->hopopt)
+ ipv6_push_exthdr(skb, proto, NEXTHDR_HOP, opt->hopopt);
+}
+
+void ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, u8 *proto)
+{
+ if (opt->dst1opt)
+ ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst1opt);
+}
+EXPORT_SYMBOL(ipv6_push_frag_opts);
+
+struct ipv6_txoptions *
+ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt)
+{
+ struct ipv6_txoptions *opt2;
+
+ opt2 = sock_kmalloc(sk, opt->tot_len, GFP_ATOMIC);
+ if (opt2) {
+ long dif = (char *)opt2 - (char *)opt;
+ memcpy(opt2, opt, opt->tot_len);
+ if (opt2->hopopt)
+ *((char **)&opt2->hopopt) += dif;
+ if (opt2->dst0opt)
+ *((char **)&opt2->dst0opt) += dif;
+ if (opt2->dst1opt)
+ *((char **)&opt2->dst1opt) += dif;
+ if (opt2->srcrt)
+ *((char **)&opt2->srcrt) += dif;
+ refcount_set(&opt2->refcnt, 1);
+ }
+ return opt2;
+}
+EXPORT_SYMBOL_GPL(ipv6_dup_options);
+
+static void ipv6_renew_option(int renewtype,
+ struct ipv6_opt_hdr **dest,
+ struct ipv6_opt_hdr *old,
+ struct ipv6_opt_hdr *new,
+ int newtype, char **p)
+{
+ struct ipv6_opt_hdr *src;
+
+ src = (renewtype == newtype ? new : old);
+ if (!src)
+ return;
+
+ memcpy(*p, src, ipv6_optlen(src));
+ *dest = (struct ipv6_opt_hdr *)*p;
+ *p += CMSG_ALIGN(ipv6_optlen(*dest));
+}
+
+/**
+ * ipv6_renew_options - replace a specific ext hdr with a new one.
+ *
+ * @sk: sock from which to allocate memory
+ * @opt: original options
+ * @newtype: option type to replace in @opt
+ * @newopt: new option of type @newtype to replace (user-mem)
+ *
+ * Returns a new set of options which is a copy of @opt with the
+ * option type @newtype replaced with @newopt.
+ *
+ * @opt may be NULL, in which case a new set of options is returned
+ * containing just @newopt.
+ *
+ * @newopt may be NULL, in which case the specified option type is
+ * not copied into the new set of options.
+ *
+ * The new set of options is allocated from the socket option memory
+ * buffer of @sk.
+ */
+struct ipv6_txoptions *
+ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt,
+ int newtype, struct ipv6_opt_hdr *newopt)
+{
+ int tot_len = 0;
+ char *p;
+ struct ipv6_txoptions *opt2;
+
+ if (opt) {
+ if (newtype != IPV6_HOPOPTS && opt->hopopt)
+ tot_len += CMSG_ALIGN(ipv6_optlen(opt->hopopt));
+ if (newtype != IPV6_RTHDRDSTOPTS && opt->dst0opt)
+ tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst0opt));
+ if (newtype != IPV6_RTHDR && opt->srcrt)
+ tot_len += CMSG_ALIGN(ipv6_optlen(opt->srcrt));
+ if (newtype != IPV6_DSTOPTS && opt->dst1opt)
+ tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst1opt));
+ }
+
+ if (newopt)
+ tot_len += CMSG_ALIGN(ipv6_optlen(newopt));
+
+ if (!tot_len)
+ return NULL;
+
+ tot_len += sizeof(*opt2);
+ opt2 = sock_kmalloc(sk, tot_len, GFP_ATOMIC);
+ if (!opt2)
+ return ERR_PTR(-ENOBUFS);
+
+ memset(opt2, 0, tot_len);
+ refcount_set(&opt2->refcnt, 1);
+ opt2->tot_len = tot_len;
+ p = (char *)(opt2 + 1);
+
+ ipv6_renew_option(IPV6_HOPOPTS, &opt2->hopopt,
+ (opt ? opt->hopopt : NULL),
+ newopt, newtype, &p);
+ ipv6_renew_option(IPV6_RTHDRDSTOPTS, &opt2->dst0opt,
+ (opt ? opt->dst0opt : NULL),
+ newopt, newtype, &p);
+ ipv6_renew_option(IPV6_RTHDR,
+ (struct ipv6_opt_hdr **)&opt2->srcrt,
+ (opt ? (struct ipv6_opt_hdr *)opt->srcrt : NULL),
+ newopt, newtype, &p);
+ ipv6_renew_option(IPV6_DSTOPTS, &opt2->dst1opt,
+ (opt ? opt->dst1opt : NULL),
+ newopt, newtype, &p);
+
+ opt2->opt_nflen = (opt2->hopopt ? ipv6_optlen(opt2->hopopt) : 0) +
+ (opt2->dst0opt ? ipv6_optlen(opt2->dst0opt) : 0) +
+ (opt2->srcrt ? ipv6_optlen(opt2->srcrt) : 0);
+ opt2->opt_flen = (opt2->dst1opt ? ipv6_optlen(opt2->dst1opt) : 0);
+
+ return opt2;
+}
+
+struct ipv6_txoptions *ipv6_fixup_options(struct ipv6_txoptions *opt_space,
+ struct ipv6_txoptions *opt)
+{
+ /*
+ * ignore the dest before srcrt unless srcrt is being included.
+ * --yoshfuji
+ */
+ if (opt && opt->dst0opt && !opt->srcrt) {
+ if (opt_space != opt) {
+ memcpy(opt_space, opt, sizeof(*opt_space));
+ opt = opt_space;
+ }
+ opt->opt_nflen -= ipv6_optlen(opt->dst0opt);
+ opt->dst0opt = NULL;
+ }
+
+ return opt;
+}
+EXPORT_SYMBOL_GPL(ipv6_fixup_options);
+
+/**
+ * fl6_update_dst - update flowi destination address with info given
+ * by srcrt option, if any.
+ *
+ * @fl6: flowi6 for which daddr is to be updated
+ * @opt: struct ipv6_txoptions in which to look for srcrt opt
+ * @orig: copy of original daddr address if modified
+ *
+ * Returns NULL if no txoptions or no srcrt, otherwise returns orig
+ * and initial value of fl6->daddr set in orig
+ */
+struct in6_addr *fl6_update_dst(struct flowi6 *fl6,
+ const struct ipv6_txoptions *opt,
+ struct in6_addr *orig)
+{
+ if (!opt || !opt->srcrt)
+ return NULL;
+
+ *orig = fl6->daddr;
+
+ switch (opt->srcrt->type) {
+ case IPV6_SRCRT_TYPE_0:
+ case IPV6_SRCRT_STRICT:
+ case IPV6_SRCRT_TYPE_2:
+ fl6->daddr = *((struct rt0_hdr *)opt->srcrt)->addr;
+ break;
+ case IPV6_SRCRT_TYPE_4:
+ {
+ struct ipv6_sr_hdr *srh = (struct ipv6_sr_hdr *)opt->srcrt;
+
+ fl6->daddr = srh->segments[srh->segments_left];
+ break;
+ }
+ default:
+ return NULL;
+ }
+
+ return orig;
+}
+EXPORT_SYMBOL_GPL(fl6_update_dst);
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-24 11:17:47 +0000