From patchwork Fri Sep 8 12:06:20 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Florian Westphal X-Patchwork-Id: 13377388 X-Patchwork-Delegate: kuba@kernel.org Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 533EE567F for ; Fri, 8 Sep 2023 12:06:49 +0000 (UTC) Received: from Chamillionaire.breakpoint.cc (Chamillionaire.breakpoint.cc [IPv6:2a0a:51c0:0:237:300::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AA7BC1BC5 for ; Fri, 8 Sep 2023 05:06:47 -0700 (PDT) Received: from fw by Chamillionaire.breakpoint.cc with local (Exim 4.92) (envelope-from ) id 1qeaG6-00062u-BY; Fri, 08 Sep 2023 14:06:46 +0200 From: Florian Westphal To: Cc: steffen.klassert@secunet.com, herbert@gondor.apana.org.au, Florian Westphal Subject: [RFC ipsec-next 3/3] xfrm: policy: replace session decode with flow dissector Date: Fri, 8 Sep 2023 14:06:20 +0200 Message-ID: <20230908120628.26164-4-fw@strlen.de> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230908120628.26164-1-fw@strlen.de> References: <20230908120628.26164-1-fw@strlen.de> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Spam-Status: No, score=-1.7 required=5.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,RCVD_IN_DNSWL_BLOCKED,SPF_HELO_PASS, SPF_PASS autolearn=no autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net X-Patchwork-Delegate: kuba@kernel.org X-Patchwork-State: RFC xfrm needs to populate ipv4/v6 flow struct for route lookup. In the past there were several bugs in this code: - callers that forget to reload header pointers after xfrm_decode_session() (it may pull headers). - access past the linear header area Meanwhile network core gained a packet dissector as well. This switches xfrm to the generic flow dissector. Signed-off-by: Florian Westphal --- net/xfrm/xfrm_policy.c | 266 +++++++++++++++++------------------------ 1 file changed, 108 insertions(+), 158 deletions(-) diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c index 5efdd20a4fb6..2d90eb4e2d31 100644 --- a/net/xfrm/xfrm_policy.c +++ b/net/xfrm/xfrm_policy.c @@ -149,6 +149,23 @@ 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_tags tags; + struct flow_dissector_key_icmp icmp; + struct flow_dissector_key_ports ports; + struct flow_dissector_key_keyid gre; + struct flow_dissector_ipv6_mh ipv6mh; +}; + +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; @@ -3367,191 +3384,77 @@ 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->flowlabel = flkeys->tags.flow_label; + + fl6->fl6_icmp_type = flkeys->icmp.type; + fl6->fl6_icmp_type = flkeys->icmp.code; + fl6->fl6_gre_key = flkeys->gre.keyid; + fl6->fl6_mh_type = flkeys->ipv6mh.mh_type; } #endif int __xfrm_decode_session(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(skb, &xfrm_session_dissector, &flkeys, 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: @@ -4253,8 +4156,55 @@ 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_FLOW_LABEL, + .offset = offsetof(struct xfrm_flow_keys, tags), + }, + { + .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), + }, + { + .key_id = FLOW_DISSECTOR_KEY_IPV6MH, + .offset = offsetof(struct xfrm_flow_keys, ipv6mh), + }, +}; + 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();