From: Florian Westphal <fw@strlen.de> mainline inclusion from mainline-v6.7-rc1 commit 7a0207094f1b14b2a690594e9b3587dddff0be5d category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IBRT1V Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- xfrm needs to populate ipv4/v6 flow struct for route lookup. In the past there were several bugs in this code: 1. callers that forget to reload header pointers after xfrm_decode_session() (it may pull headers). 2. bugs in decoding where accesses past skb->data occurred. Meanwhile network core gained a packet dissector as well. This switches xfrm to the flow dissector. Changes since RFC: Drop ipv6 mobiliy header support, AFAIU noone uses this. Drop extraction of flowlabel, replaced code doesn't set it either. Reviewed-by: Simon Horman <horms@kernel.org> Link: https://lore.kernel.org/netdev/20230908120628.26164-3-fw@strlen.de/ Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com> Signed-off-by: Wang Liang <wangliang74@huawei.com> --- net/xfrm/xfrm_policy.c | 253 ++++++++++++++++------------------------- 1 file changed, 95 insertions(+), 158 deletions(-) diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c index 5099fc3ad0d4..d3dea07363fc 100644 --- a/net/xfrm/xfrm_policy.c +++ b/net/xfrm/xfrm_policy.c @@ -149,6 +149,21 @@ struct xfrm_pol_inexact_candidates { struct hlist_head *res[XFRM_POL_CAND_MAX]; }; +struct xfrm_flow_keys { + struct flow_dissector_key_basic basic; + struct flow_dissector_key_control control; + union { + struct flow_dissector_key_ipv4_addrs ipv4; + struct flow_dissector_key_ipv6_addrs ipv6; + } addrs; + struct flow_dissector_key_ip ip; + struct flow_dissector_key_icmp icmp; + struct flow_dissector_key_ports ports; + struct flow_dissector_key_keyid gre; +}; + +static struct flow_dissector xfrm_session_dissector __ro_after_init; + static DEFINE_SPINLOCK(xfrm_if_cb_lock); static struct xfrm_if_cb const __rcu *xfrm_if_cb __read_mostly; @@ -3398,191 +3413,74 @@ xfrm_policy_ok(const struct xfrm_tmpl *tmpl, const struct sec_path *sp, int star } static void -decode_session4(struct sk_buff *skb, struct flowi *fl, bool reverse) +decode_session4(const struct xfrm_flow_keys *flkeys, struct flowi *fl, bool reverse) { - const struct iphdr *iph = ip_hdr(skb); - int ihl = iph->ihl; - u8 *xprth = skb_network_header(skb) + ihl * 4; struct flowi4 *fl4 = &fl->u.ip4; memset(fl4, 0, sizeof(struct flowi4)); - fl4->flowi4_proto = iph->protocol; - fl4->daddr = reverse ? iph->saddr : iph->daddr; - fl4->saddr = reverse ? iph->daddr : iph->saddr; - fl4->flowi4_tos = iph->tos & ~INET_ECN_MASK; - - if (!ip_is_fragment(iph)) { - switch (iph->protocol) { - case IPPROTO_UDP: - case IPPROTO_UDPLITE: - case IPPROTO_TCP: - case IPPROTO_SCTP: - case IPPROTO_DCCP: - if (xprth + 4 < skb->data || - pskb_may_pull(skb, xprth + 4 - skb->data)) { - __be16 *ports; - - xprth = skb_network_header(skb) + ihl * 4; - ports = (__be16 *)xprth; - - fl4->fl4_sport = ports[!!reverse]; - fl4->fl4_dport = ports[!reverse]; - } - break; - case IPPROTO_ICMP: - if (xprth + 2 < skb->data || - pskb_may_pull(skb, xprth + 2 - skb->data)) { - u8 *icmp; - - xprth = skb_network_header(skb) + ihl * 4; - icmp = xprth; - - fl4->fl4_icmp_type = icmp[0]; - fl4->fl4_icmp_code = icmp[1]; - } - break; - case IPPROTO_GRE: - if (xprth + 12 < skb->data || - pskb_may_pull(skb, xprth + 12 - skb->data)) { - __be16 *greflags; - __be32 *gre_hdr; - - xprth = skb_network_header(skb) + ihl * 4; - greflags = (__be16 *)xprth; - gre_hdr = (__be32 *)xprth; - - if (greflags[0] & GRE_KEY) { - if (greflags[0] & GRE_CSUM) - gre_hdr++; - fl4->fl4_gre_key = gre_hdr[1]; - } - } - break; - default: - break; - } + if (reverse) { + fl4->saddr = flkeys->addrs.ipv4.dst; + fl4->daddr = flkeys->addrs.ipv4.src; + fl4->fl4_sport = flkeys->ports.dst; + fl4->fl4_dport = flkeys->ports.src; + } else { + fl4->saddr = flkeys->addrs.ipv4.src; + fl4->daddr = flkeys->addrs.ipv4.dst; + fl4->fl4_sport = flkeys->ports.src; + fl4->fl4_dport = flkeys->ports.dst; } + + fl4->flowi4_proto = flkeys->basic.ip_proto; + fl4->flowi4_tos = flkeys->ip.tos; + fl4->fl4_icmp_type = flkeys->icmp.type; + fl4->fl4_icmp_type = flkeys->icmp.code; + fl4->fl4_gre_key = flkeys->gre.keyid; } #if IS_ENABLED(CONFIG_IPV6) static void -decode_session6(struct sk_buff *skb, struct flowi *fl, bool reverse) +decode_session6(const struct xfrm_flow_keys *flkeys, struct flowi *fl, bool reverse) { struct flowi6 *fl6 = &fl->u.ip6; - int onlyproto = 0; - const struct ipv6hdr *hdr = ipv6_hdr(skb); - u32 offset = sizeof(*hdr); - struct ipv6_opt_hdr *exthdr; - const unsigned char *nh = skb_network_header(skb); - u16 nhoff = IP6CB(skb)->nhoff; - u8 nexthdr; - - if (!nhoff) - nhoff = offsetof(struct ipv6hdr, nexthdr); - - nexthdr = nh[nhoff]; memset(fl6, 0, sizeof(struct flowi6)); - fl6->daddr = reverse ? hdr->saddr : hdr->daddr; - fl6->saddr = reverse ? hdr->daddr : hdr->saddr; - - while (nh + offset + sizeof(*exthdr) < skb->data || - pskb_may_pull(skb, nh + offset + sizeof(*exthdr) - skb->data)) { - nh = skb_network_header(skb); - exthdr = (struct ipv6_opt_hdr *)(nh + offset); - - switch (nexthdr) { - case NEXTHDR_FRAGMENT: - onlyproto = 1; - fallthrough; - case NEXTHDR_ROUTING: - case NEXTHDR_HOP: - case NEXTHDR_DEST: - offset += ipv6_optlen(exthdr); - nexthdr = exthdr->nexthdr; - break; - case IPPROTO_UDP: - case IPPROTO_UDPLITE: - case IPPROTO_TCP: - case IPPROTO_SCTP: - case IPPROTO_DCCP: - if (!onlyproto && (nh + offset + 4 < skb->data || - pskb_may_pull(skb, nh + offset + 4 - skb->data))) { - __be16 *ports; - - nh = skb_network_header(skb); - ports = (__be16 *)(nh + offset); - fl6->fl6_sport = ports[!!reverse]; - fl6->fl6_dport = ports[!reverse]; - } - fl6->flowi6_proto = nexthdr; - return; - case IPPROTO_ICMPV6: - if (!onlyproto && (nh + offset + 2 < skb->data || - pskb_may_pull(skb, nh + offset + 2 - skb->data))) { - u8 *icmp; - - nh = skb_network_header(skb); - icmp = (u8 *)(nh + offset); - fl6->fl6_icmp_type = icmp[0]; - fl6->fl6_icmp_code = icmp[1]; - } - fl6->flowi6_proto = nexthdr; - return; - case IPPROTO_GRE: - if (!onlyproto && - (nh + offset + 12 < skb->data || - pskb_may_pull(skb, nh + offset + 12 - skb->data))) { - struct gre_base_hdr *gre_hdr; - __be32 *gre_key; - - nh = skb_network_header(skb); - gre_hdr = (struct gre_base_hdr *)(nh + offset); - gre_key = (__be32 *)(gre_hdr + 1); - - if (gre_hdr->flags & GRE_KEY) { - if (gre_hdr->flags & GRE_CSUM) - gre_key++; - fl6->fl6_gre_key = *gre_key; - } - } - fl6->flowi6_proto = nexthdr; - return; - -#if IS_ENABLED(CONFIG_IPV6_MIP6) - case IPPROTO_MH: - offset += ipv6_optlen(exthdr); - if (!onlyproto && (nh + offset + 3 < skb->data || - pskb_may_pull(skb, nh + offset + 3 - skb->data))) { - struct ip6_mh *mh; - - nh = skb_network_header(skb); - mh = (struct ip6_mh *)(nh + offset); - fl6->fl6_mh_type = mh->ip6mh_type; - } - fl6->flowi6_proto = nexthdr; - return; -#endif - default: - fl6->flowi6_proto = nexthdr; - return; - } + if (reverse) { + fl6->saddr = flkeys->addrs.ipv6.dst; + fl6->daddr = flkeys->addrs.ipv6.src; + fl6->fl6_sport = flkeys->ports.dst; + fl6->fl6_dport = flkeys->ports.src; + } else { + fl6->saddr = flkeys->addrs.ipv6.src; + fl6->daddr = flkeys->addrs.ipv6.dst; + fl6->fl6_sport = flkeys->ports.src; + fl6->fl6_dport = flkeys->ports.dst; } + + fl6->flowi6_proto = flkeys->basic.ip_proto; + fl6->fl6_icmp_type = flkeys->icmp.type; + fl6->fl6_icmp_type = flkeys->icmp.code; + fl6->fl6_gre_key = flkeys->gre.keyid; } #endif int __xfrm_decode_session(struct net *net, struct sk_buff *skb, struct flowi *fl, unsigned int family, int reverse) { + struct xfrm_flow_keys flkeys; + + memset(&flkeys, 0, sizeof(flkeys)); + __skb_flow_dissect(net, skb, &xfrm_session_dissector, &flkeys, + NULL, 0, 0, 0, FLOW_DISSECTOR_F_STOP_AT_ENCAP); + switch (family) { case AF_INET: - decode_session4(skb, fl, reverse); + decode_session4(&flkeys, fl, reverse); break; #if IS_ENABLED(CONFIG_IPV6) case AF_INET6: - decode_session6(skb, fl, reverse); + decode_session6(&flkeys, fl, reverse); break; #endif default: @@ -4279,8 +4177,47 @@ static struct pernet_operations __net_initdata xfrm_net_ops = { .exit = xfrm_net_exit, }; +static const struct flow_dissector_key xfrm_flow_dissector_keys[] = { + { + .key_id = FLOW_DISSECTOR_KEY_CONTROL, + .offset = offsetof(struct xfrm_flow_keys, control), + }, + { + .key_id = FLOW_DISSECTOR_KEY_BASIC, + .offset = offsetof(struct xfrm_flow_keys, basic), + }, + { + .key_id = FLOW_DISSECTOR_KEY_IPV4_ADDRS, + .offset = offsetof(struct xfrm_flow_keys, addrs.ipv4), + }, + { + .key_id = FLOW_DISSECTOR_KEY_IPV6_ADDRS, + .offset = offsetof(struct xfrm_flow_keys, addrs.ipv6), + }, + { + .key_id = FLOW_DISSECTOR_KEY_PORTS, + .offset = offsetof(struct xfrm_flow_keys, ports), + }, + { + .key_id = FLOW_DISSECTOR_KEY_GRE_KEYID, + .offset = offsetof(struct xfrm_flow_keys, gre), + }, + { + .key_id = FLOW_DISSECTOR_KEY_IP, + .offset = offsetof(struct xfrm_flow_keys, ip), + }, + { + .key_id = FLOW_DISSECTOR_KEY_ICMP, + .offset = offsetof(struct xfrm_flow_keys, icmp), + }, +}; + void __init xfrm_init(void) { + skb_flow_dissector_init(&xfrm_session_dissector, + xfrm_flow_dissector_keys, + ARRAY_SIZE(xfrm_flow_dissector_keys)); + register_pernet_subsys(&xfrm_net_ops); xfrm_dev_init(); xfrm_input_init(); -- 2.34.1