cregit-Linux how code gets into the kernel

Release 4.11 net/ipv6/exthdrs.c

Directory: net/ipv6
/*
 *      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>
 *
 *      This program is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU General Public License
 *      as published by the Free Software Foundation; either version
 *      2 of the License, or (at your option) any later version.
 */

/* 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 <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) { 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; case 2: /* send ICMP PARM PROB regardless and drop packet */ icmpv6_param_prob(skb, ICMPV6_UNK_OPTION, optoff); return false; } kfree_skb(skb); return false; }

Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds (pre-git)7080.46%114.29%
Arnaldo Carvalho de Melo66.90%228.57%
Linus Torvalds55.75%114.29%
Eric Dumazet44.60%114.29%
Stephen Rothwell11.15%114.29%
Herbert Xu11.15%114.29%
Total87100.00%7100.00%

/* Parse tlv encoded option header (hop-by-hop or destination) */
static bool ip6_parse_tlv(const struct tlvtype_proc *procs, struct sk_buff *skb) { const struct tlvtype_proc *curr; const unsigned char *nh = skb_network_header(skb); int off = skb_network_header_len(skb); int len = (skb_transport_header(skb)[1] + 1) << 3; int padlen = 0; if (skb_transport_offset(skb) + len > skb_headlen(skb)) goto bad; off += 2; len -= 2; while (len > 0) { int optlen = nh[off + 1] + 2; int i; switch (nh[off]) { case IPV6_TLV_PAD1: optlen = 1; padlen++; if (padlen > 7) goto bad; break; case 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; } break; default: /* Other TLV code so scan list */ if (optlen > len) 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) { if (ip6_tlvopt_unknown(skb, off) == 0) return false; } padlen = 0; break; } off += optlen; len -= optlen; } if (len == 0) return true; bad: kfree_skb(skb); return false; }

Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds (pre-git)16654.61%17.69%
Eldad Zack6922.70%323.08%
Linus Torvalds3712.17%215.38%
Arnaldo Carvalho de Melo206.58%430.77%
Eric Dumazet82.63%17.69%
Herbert Xu30.99%17.69%
Hideaki Yoshifuji / 吉藤英明10.33%17.69%
Total304100.00%13100.00%

/***************************** 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); struct in6_addr tmp_addr; 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; tmp_addr = ipv6h->saddr; ipv6h->saddr = hao->addr; hao->addr = tmp_addr; if (skb->tstamp == 0) __net_timestamp(skb); return true; discard: kfree_skb(skb); return false; }

Contributors

PersonTokensPropCommitsCommitProp
Masahide Nakamura25988.70%110.00%
Arnaldo Carvalho de Melo124.11%220.00%
Herbert Xu103.42%220.00%
Eric Dumazet31.03%110.00%
Joe Perches31.03%110.00%
Alexey Dobriyan31.03%110.00%
Harvey Harrison20.68%220.00%
Total292100.00%10100.00%

#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_skb_parm *opt = IP6CB(skb); #if IS_ENABLED(CONFIG_IPV6_MIP6) __u16 dstbuf; #endif struct dst_entry *dst = skb_dst(skb); 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), ip6_dst_idev(dst), IPSTATS_MIB_INHDRERRORS); kfree_skb(skb); return -1; } 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)) { skb->transport_header += (skb_transport_header(skb)[1] + 1) << 3; opt = IP6CB(skb); #if IS_ENABLED(CONFIG_IPV6_MIP6) opt->nhoff = dstbuf; #else opt->nhoff = opt->dst1; #endif return 1; } __IP6_INC_STATS(dev_net(dst->dev), ip6_dst_idev(dst), IPSTATS_MIB_INHDRERRORS); return -1; }

Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds4821.33%14.55%
Masahide Nakamura4520.00%313.64%
Linus Torvalds (pre-git)4520.00%14.55%
Hideaki Yoshifuji / 吉藤英明3314.67%522.73%
Arnaldo Carvalho de Melo177.56%418.18%
Denis V. Lunev135.78%14.55%
Eric Dumazet94.00%29.09%
Shirley Ma62.67%14.55%
Patrick McHardy31.33%14.55%
Américo Wang31.33%14.55%
Herbert Xu20.89%14.55%
Mitsuru Kanda10.44%14.55%
Total225100.00%22100.00%


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); }

Contributors

PersonTokensPropCommitsCommitProp
David Lebrun9584.07%125.00%
Linus Torvalds (pre-git)1614.16%125.00%
Herbert Xu10.88%125.00%
Hideaki Yoshifuji / 吉藤英明10.88%125.00%
Total113100.00%4100.00%


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, ip6_dst_idev(skb_dst(skb)), 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, ip6_dst_idev(skb_dst(skb)), 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; }

Contributors

PersonTokensPropCommitsCommitProp
David Lebrun54190.47%330.00%
Hideaki Yoshifuji / 吉藤英明325.35%330.00%
Linus Torvalds (pre-git)152.51%110.00%
Denis V. Lunev50.84%110.00%
Linus Torvalds40.67%110.00%
Eric Dumazet10.17%110.00%
Total598100.00%10100.00%

/******************************** Routing header. ********************************/ /* called with rcu_read_lock() */
static int ipv6_rthdr_rcv(struct sk_buff *skb) { struct inet6_skb_parm *opt = IP6CB(skb); struct in6_addr *addr = NULL; struct in6_addr daddr; struct inet6_dev *idev; 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, ip6_dst_idev(skb_dst(skb)), 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, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_INADDRERRORS); kfree_skb(skb); return -1; } /* segment routing */ if (hdr->type == IPV6_SRCRT_TYPE_4) return ipv6_srh_rcv(skb); 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, ip6_dst_idev(skb_dst(skb)), 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, ip6_dst_idev(skb_dst(skb)), 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, ip6_dst_idev(skb_dst(skb)), 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, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_INADDRERRORS); kfree_skb(skb); return -1; } if (!ipv6_chk_home_addr(dev_net(skb_dst(skb)->dev), addr)) { __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_INADDRERRORS); kfree_skb(skb); return -1; } break; #endif default: break; } if (ipv6_addr_is_multicast(addr)) { __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 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, ip6_dst_idev(skb_dst(skb)), 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, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_INHDRERRORS); icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, (&hdr->type) - skb_network_header(skb)); return -1; }

Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds (pre-git)24925.67%13.23%
David Lebrun20020.62%13.23%
Hideaki Yoshifuji / 吉藤英明16216.70%929.03%
Masahide Nakamura16016.49%26.45%
Eric Dumazet505.15%26.45%
Linus Torvalds404.12%13.23%
Arnaldo Carvalho de Melo394.02%516.13%
Denis V. Lunev262.68%26.45%
Shirley Ma202.06%13.23%
Herbert Xu90.93%13.23%
Alexey Dobriyan50.52%13.23%
Patrick McHardy40.41%26.45%
Américo Wang30.31%13.23%
Mitsuru Kanda20.21%13.23%
Daniel Lezcano10.10%13.23%
Total970100.00%31100.00%

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; }

Contributors

PersonTokensPropCommitsCommitProp
Daniel Lezcano6774.44%125.00%
Mitsuru Kanda1617.78%125.00%
Vlad Yasevich77.78%250.00%
Total90100.00%4100.00%

;
void ipv6_exthdrs_exit(void) { inet6_del_protocol(&nodata_protocol, IPPROTO_NONE); inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS)