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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sockopt_inherit.c (2305B)

      1// SPDX-License-Identifier: GPL-2.0
      2#include <linux/bpf.h>
      3#include <bpf/bpf_helpers.h>
      4
      5char _license[] SEC("license") = "GPL";
      6
      7#define SOL_CUSTOM			0xdeadbeef
      8#define CUSTOM_INHERIT1			0
      9#define CUSTOM_INHERIT2			1
     10#define CUSTOM_LISTENER			2
     11
     12struct sockopt_inherit {
     13	__u8 val;
     14};
     15
     16struct {
     17	__uint(type, BPF_MAP_TYPE_SK_STORAGE);
     18	__uint(map_flags, BPF_F_NO_PREALLOC | BPF_F_CLONE);
     19	__type(key, int);
     20	__type(value, struct sockopt_inherit);
     21} cloned1_map SEC(".maps");
     22
     23struct {
     24	__uint(type, BPF_MAP_TYPE_SK_STORAGE);
     25	__uint(map_flags, BPF_F_NO_PREALLOC | BPF_F_CLONE);
     26	__type(key, int);
     27	__type(value, struct sockopt_inherit);
     28} cloned2_map SEC(".maps");
     29
     30struct {
     31	__uint(type, BPF_MAP_TYPE_SK_STORAGE);
     32	__uint(map_flags, BPF_F_NO_PREALLOC);
     33	__type(key, int);
     34	__type(value, struct sockopt_inherit);
     35} listener_only_map SEC(".maps");
     36
     37static __inline struct sockopt_inherit *get_storage(struct bpf_sockopt *ctx)
     38{
     39	if (ctx->optname == CUSTOM_INHERIT1)
     40		return bpf_sk_storage_get(&cloned1_map, ctx->sk, 0,
     41					  BPF_SK_STORAGE_GET_F_CREATE);
     42	else if (ctx->optname == CUSTOM_INHERIT2)
     43		return bpf_sk_storage_get(&cloned2_map, ctx->sk, 0,
     44					  BPF_SK_STORAGE_GET_F_CREATE);
     45	else
     46		return bpf_sk_storage_get(&listener_only_map, ctx->sk, 0,
     47					  BPF_SK_STORAGE_GET_F_CREATE);
     48}
     49
     50SEC("cgroup/getsockopt")
     51int _getsockopt(struct bpf_sockopt *ctx)
     52{
     53	__u8 *optval_end = ctx->optval_end;
     54	struct sockopt_inherit *storage;
     55	__u8 *optval = ctx->optval;
     56
     57	if (ctx->level != SOL_CUSTOM)
     58		return 1; /* only interested in SOL_CUSTOM */
     59
     60	if (optval + 1 > optval_end)
     61		return 0; /* EPERM, bounds check */
     62
     63	storage = get_storage(ctx);
     64	if (!storage)
     65		return 0; /* EPERM, couldn't get sk storage */
     66
     67	ctx->retval = 0; /* Reset system call return value to zero */
     68
     69	optval[0] = storage->val;
     70	ctx->optlen = 1;
     71
     72	return 1;
     73}
     74
     75SEC("cgroup/setsockopt")
     76int _setsockopt(struct bpf_sockopt *ctx)
     77{
     78	__u8 *optval_end = ctx->optval_end;
     79	struct sockopt_inherit *storage;
     80	__u8 *optval = ctx->optval;
     81
     82	if (ctx->level != SOL_CUSTOM)
     83		return 1; /* only interested in SOL_CUSTOM */
     84
     85	if (optval + 1 > optval_end)
     86		return 0; /* EPERM, bounds check */
     87
     88	storage = get_storage(ctx);
     89	if (!storage)
     90		return 0; /* EPERM, couldn't get sk storage */
     91
     92	storage->val = optval[0];
     93	ctx->optlen = -1;
     94
     95	return 1;
     96}