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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sendmsg4_prog.c (1252B)

      1// SPDX-License-Identifier: GPL-2.0
      2// Copyright (c) 2018 Facebook
      3
      4#include <linux/stddef.h>
      5#include <linux/bpf.h>
      6#include <sys/socket.h>
      7
      8#include <bpf/bpf_helpers.h>
      9#include <bpf/bpf_endian.h>
     10
     11#include <bpf_sockopt_helpers.h>
     12
     13#define SRC1_IP4		0xAC100001U /* 172.16.0.1 */
     14#define SRC2_IP4		0x00000000U
     15#define SRC_REWRITE_IP4		0x7f000004U
     16#define DST_IP4			0xC0A801FEU /* 192.168.1.254 */
     17#define DST_REWRITE_IP4		0x7f000001U
     18#define DST_PORT		4040
     19#define DST_REWRITE_PORT4	4444
     20
     21SEC("cgroup/sendmsg4")
     22int sendmsg_v4_prog(struct bpf_sock_addr *ctx)
     23{
     24	int prio;
     25
     26	if (ctx->type != SOCK_DGRAM)
     27		return 0;
     28
     29	if (!get_set_sk_priority(ctx))
     30		return 0;
     31
     32	/* Rewrite source. */
     33	if (ctx->msg_src_ip4 == bpf_htonl(SRC1_IP4) ||
     34	    ctx->msg_src_ip4 == bpf_htonl(SRC2_IP4)) {
     35		ctx->msg_src_ip4 = bpf_htonl(SRC_REWRITE_IP4);
     36	} else {
     37		/* Unexpected source. Reject sendmsg. */
     38		return 0;
     39	}
     40
     41	/* Rewrite destination. */
     42	if ((ctx->user_ip4 >> 24) == (bpf_htonl(DST_IP4) >> 24) &&
     43	     ctx->user_port == bpf_htons(DST_PORT)) {
     44		ctx->user_ip4 = bpf_htonl(DST_REWRITE_IP4);
     45		ctx->user_port = bpf_htons(DST_REWRITE_PORT4);
     46	} else {
     47		/* Unexpected source. Reject sendmsg. */
     48		return 0;
     49	}
     50
     51	return 1;
     52}
     53
     54char _license[] SEC("license") = "GPL";