cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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xfrm4_input.c (4292B)

      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 * xfrm4_input.c
      4 *
      5 * Changes:
      6 *	YOSHIFUJI Hideaki @USAGI
      7 *		Split up af-specific portion
      8 *	Derek Atkins <derek@ihtfp.com>
      9 *		Add Encapsulation support
     10 *
     11 */
     12
     13#include <linux/slab.h>
     14#include <linux/module.h>
     15#include <linux/string.h>
     16#include <linux/netfilter.h>
     17#include <linux/netfilter_ipv4.h>
     18#include <net/ip.h>
     19#include <net/xfrm.h>
     20
     21static int xfrm4_rcv_encap_finish2(struct net *net, struct sock *sk,
     22				   struct sk_buff *skb)
     23{
     24	return dst_input(skb);
     25}
     26
     27static inline int xfrm4_rcv_encap_finish(struct net *net, struct sock *sk,
     28					 struct sk_buff *skb)
     29{
     30	if (!skb_dst(skb)) {
     31		const struct iphdr *iph = ip_hdr(skb);
     32
     33		if (ip_route_input_noref(skb, iph->daddr, iph->saddr,
     34					 iph->tos, skb->dev))
     35			goto drop;
     36	}
     37
     38	if (xfrm_trans_queue(skb, xfrm4_rcv_encap_finish2))
     39		goto drop;
     40
     41	return 0;
     42drop:
     43	kfree_skb(skb);
     44	return NET_RX_DROP;
     45}
     46
     47int xfrm4_transport_finish(struct sk_buff *skb, int async)
     48{
     49	struct xfrm_offload *xo = xfrm_offload(skb);
     50	struct iphdr *iph = ip_hdr(skb);
     51
     52	iph->protocol = XFRM_MODE_SKB_CB(skb)->protocol;
     53
     54#ifndef CONFIG_NETFILTER
     55	if (!async)
     56		return -iph->protocol;
     57#endif
     58
     59	__skb_push(skb, skb->data - skb_network_header(skb));
     60	iph->tot_len = htons(skb->len);
     61	ip_send_check(iph);
     62
     63	if (xo && (xo->flags & XFRM_GRO)) {
     64		skb_mac_header_rebuild(skb);
     65		skb_reset_transport_header(skb);
     66		return 0;
     67	}
     68
     69	NF_HOOK(NFPROTO_IPV4, NF_INET_PRE_ROUTING,
     70		dev_net(skb->dev), NULL, skb, skb->dev, NULL,
     71		xfrm4_rcv_encap_finish);
     72	return 0;
     73}
     74
     75/* If it's a keepalive packet, then just eat it.
     76 * If it's an encapsulated packet, then pass it to the
     77 * IPsec xfrm input.
     78 * Returns 0 if skb passed to xfrm or was dropped.
     79 * Returns >0 if skb should be passed to UDP.
     80 * Returns <0 if skb should be resubmitted (-ret is protocol)
     81 */
     82int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb)
     83{
     84	struct udp_sock *up = udp_sk(sk);
     85	struct udphdr *uh;
     86	struct iphdr *iph;
     87	int iphlen, len;
     88
     89	__u8 *udpdata;
     90	__be32 *udpdata32;
     91	__u16 encap_type = up->encap_type;
     92
     93	/* if this is not encapsulated socket, then just return now */
     94	if (!encap_type)
     95		return 1;
     96
     97	/* If this is a paged skb, make sure we pull up
     98	 * whatever data we need to look at. */
     99	len = skb->len - sizeof(struct udphdr);
    100	if (!pskb_may_pull(skb, sizeof(struct udphdr) + min(len, 8)))
    101		return 1;
    102
    103	/* Now we can get the pointers */
    104	uh = udp_hdr(skb);
    105	udpdata = (__u8 *)uh + sizeof(struct udphdr);
    106	udpdata32 = (__be32 *)udpdata;
    107
    108	switch (encap_type) {
    109	default:
    110	case UDP_ENCAP_ESPINUDP:
    111		/* Check if this is a keepalive packet.  If so, eat it. */
    112		if (len == 1 && udpdata[0] == 0xff) {
    113			goto drop;
    114		} else if (len > sizeof(struct ip_esp_hdr) && udpdata32[0] != 0) {
    115			/* ESP Packet without Non-ESP header */
    116			len = sizeof(struct udphdr);
    117		} else
    118			/* Must be an IKE packet.. pass it through */
    119			return 1;
    120		break;
    121	case UDP_ENCAP_ESPINUDP_NON_IKE:
    122		/* Check if this is a keepalive packet.  If so, eat it. */
    123		if (len == 1 && udpdata[0] == 0xff) {
    124			goto drop;
    125		} else if (len > 2 * sizeof(u32) + sizeof(struct ip_esp_hdr) &&
    126			   udpdata32[0] == 0 && udpdata32[1] == 0) {
    127
    128			/* ESP Packet with Non-IKE marker */
    129			len = sizeof(struct udphdr) + 2 * sizeof(u32);
    130		} else
    131			/* Must be an IKE packet.. pass it through */
    132			return 1;
    133		break;
    134	}
    135
    136	/* At this point we are sure that this is an ESPinUDP packet,
    137	 * so we need to remove 'len' bytes from the packet (the UDP
    138	 * header and optional ESP marker bytes) and then modify the
    139	 * protocol to ESP, and then call into the transform receiver.
    140	 */
    141	if (skb_unclone(skb, GFP_ATOMIC))
    142		goto drop;
    143
    144	/* Now we can update and verify the packet length... */
    145	iph = ip_hdr(skb);
    146	iphlen = iph->ihl << 2;
    147	iph->tot_len = htons(ntohs(iph->tot_len) - len);
    148	if (skb->len < iphlen + len) {
    149		/* packet is too small!?! */
    150		goto drop;
    151	}
    152
    153	/* pull the data buffer up to the ESP header and set the
    154	 * transport header to point to ESP.  Keep UDP on the stack
    155	 * for later.
    156	 */
    157	__skb_pull(skb, len);
    158	skb_reset_transport_header(skb);
    159
    160	/* process ESP */
    161	return xfrm4_rcv_encap(skb, IPPROTO_ESP, 0, encap_type);
    162
    163drop:
    164	kfree_skb(skb);
    165	return 0;
    166}
    167
    168int xfrm4_rcv(struct sk_buff *skb)
    169{
    170	return xfrm4_rcv_spi(skb, ip_hdr(skb)->protocol, 0);
    171}
    172EXPORT_SYMBOL(xfrm4_rcv);