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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connect_force_port4.c (1978B)

      1// SPDX-License-Identifier: GPL-2.0
      2#include <string.h>
      3#include <stdbool.h>
      4
      5#include <linux/bpf.h>
      6#include <linux/in.h>
      7#include <linux/in6.h>
      8#include <sys/socket.h>
      9
     10#include <bpf/bpf_helpers.h>
     11#include <bpf/bpf_endian.h>
     12
     13#include <bpf_sockopt_helpers.h>
     14
     15char _license[] SEC("license") = "GPL";
     16
     17struct svc_addr {
     18	__be32 addr;
     19	__be16 port;
     20};
     21
     22struct {
     23	__uint(type, BPF_MAP_TYPE_SK_STORAGE);
     24	__uint(map_flags, BPF_F_NO_PREALLOC);
     25	__type(key, int);
     26	__type(value, struct svc_addr);
     27} service_mapping SEC(".maps");
     28
     29SEC("cgroup/connect4")
     30int connect4(struct bpf_sock_addr *ctx)
     31{
     32	struct sockaddr_in sa = {};
     33	struct svc_addr *orig;
     34
     35	/* Force local address to 127.0.0.1:22222. */
     36	sa.sin_family = AF_INET;
     37	sa.sin_port = bpf_htons(22222);
     38	sa.sin_addr.s_addr = bpf_htonl(0x7f000001);
     39
     40	if (bpf_bind(ctx, (struct sockaddr *)&sa, sizeof(sa)) != 0)
     41		return 0;
     42
     43	/* Rewire service 1.2.3.4:60000 to backend 127.0.0.1:60123. */
     44	if (ctx->user_port == bpf_htons(60000)) {
     45		orig = bpf_sk_storage_get(&service_mapping, ctx->sk, 0,
     46					  BPF_SK_STORAGE_GET_F_CREATE);
     47		if (!orig)
     48			return 0;
     49
     50		orig->addr = ctx->user_ip4;
     51		orig->port = ctx->user_port;
     52
     53		ctx->user_ip4 = bpf_htonl(0x7f000001);
     54		ctx->user_port = bpf_htons(60123);
     55	}
     56	return 1;
     57}
     58
     59SEC("cgroup/getsockname4")
     60int getsockname4(struct bpf_sock_addr *ctx)
     61{
     62	if (!get_set_sk_priority(ctx))
     63		return 1;
     64
     65	/* Expose local server as 1.2.3.4:60000 to client. */
     66	if (ctx->user_port == bpf_htons(60123)) {
     67		ctx->user_ip4 = bpf_htonl(0x01020304);
     68		ctx->user_port = bpf_htons(60000);
     69	}
     70	return 1;
     71}
     72
     73SEC("cgroup/getpeername4")
     74int getpeername4(struct bpf_sock_addr *ctx)
     75{
     76	struct svc_addr *orig;
     77
     78	if (!get_set_sk_priority(ctx))
     79		return 1;
     80
     81	/* Expose service 1.2.3.4:60000 as peer instead of backend. */
     82	if (ctx->user_port == bpf_htons(60123)) {
     83		orig = bpf_sk_storage_get(&service_mapping, ctx->sk, 0, 0);
     84		if (orig) {
     85			ctx->user_ip4 = orig->addr;
     86			ctx->user_port = orig->port;
     87		}
     88	}
     89	return 1;
     90}