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// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2024 Meta Platforms, Inc. and affiliates. */
#include "vmlinux.h"
#include "bpf_tracing_net.h"
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_endian.h>
#include <bpf/bpf_tracing.h>
#include "bpf_misc.h"
#include "bpf_kfuncs.h"
#include "crypto_common.h"
unsigned char key[256] = {};
u16 udp_test_port = 7777;
u32 authsize, key_len;
char algo[128] = {};
char dst[16] = {};
int status;
static int skb_dynptr_validate(struct __sk_buff *skb, struct bpf_dynptr *psrc)
{
struct ipv6hdr ip6h;
struct udphdr udph;
u32 offset;
if (skb->protocol != __bpf_constant_htons(ETH_P_IPV6))
return -1;
if (bpf_skb_load_bytes(skb, ETH_HLEN, &ip6h, sizeof(ip6h)))
return -1;
if (ip6h.nexthdr != IPPROTO_UDP)
return -1;
if (bpf_skb_load_bytes(skb, ETH_HLEN + sizeof(ip6h), &udph, sizeof(udph)))
return -1;
if (udph.dest != __bpf_htons(udp_test_port))
return -1;
offset = ETH_HLEN + sizeof(ip6h) + sizeof(udph);
if (skb->len < offset + 16)
return -1;
/* let's make sure that 16 bytes of payload are in the linear part of skb */
bpf_skb_pull_data(skb, offset + 16);
bpf_dynptr_from_skb(skb, 0, psrc);
bpf_dynptr_adjust(psrc, offset, offset + 16);
return 0;
}
SEC("syscall")
int skb_crypto_setup(void *ctx)
{
struct bpf_crypto_params params = {
.type = "skcipher",
.key_len = key_len,
.authsize = authsize,
};
struct bpf_crypto_ctx *cctx;
int err = 0;
status = 0;
if (key_len > 256) {
status = -EINVAL;
return 0;
}
__builtin_memcpy(¶ms.algo, algo, sizeof(algo));
__builtin_memcpy(¶ms.key, key, sizeof(key));
cctx = bpf_crypto_ctx_create(¶ms, sizeof(params), &err);
if (!cctx) {
status = err;
return 0;
}
err = crypto_ctx_insert(cctx);
if (err && err != -EEXIST)
status = err;
return 0;
}
SEC("tc")
int decrypt_sanity(struct __sk_buff *skb)
{
struct __crypto_ctx_value *v;
struct bpf_crypto_ctx *ctx;
struct bpf_dynptr psrc, pdst, iv;
int err;
err = skb_dynptr_validate(skb, &psrc);
if (err < 0) {
status = err;
return TC_ACT_SHOT;
}
v = crypto_ctx_value_lookup();
if (!v) {
status = -ENOENT;
return TC_ACT_SHOT;
}
ctx = v->ctx;
if (!ctx) {
status = -ENOENT;
return TC_ACT_SHOT;
}
/* dst is a global variable to make testing part easier to check. In real
* production code, a percpu map should be used to store the result.
*/
bpf_dynptr_from_mem(dst, sizeof(dst), 0, &pdst);
/* iv dynptr has to be initialized with 0 size, but proper memory region
* has to be provided anyway
*/
bpf_dynptr_from_mem(dst, 0, 0, &iv);
status = bpf_crypto_decrypt(ctx, &psrc, &pdst, &iv);
return TC_ACT_SHOT;
}
SEC("tc")
int encrypt_sanity(struct __sk_buff *skb)
{
struct __crypto_ctx_value *v;
struct bpf_crypto_ctx *ctx;
struct bpf_dynptr psrc, pdst, iv;
int err;
status = 0;
err = skb_dynptr_validate(skb, &psrc);
if (err < 0) {
status = err;
return TC_ACT_SHOT;
}
v = crypto_ctx_value_lookup();
if (!v) {
status = -ENOENT;
return TC_ACT_SHOT;
}
ctx = v->ctx;
if (!ctx) {
status = -ENOENT;
return TC_ACT_SHOT;
}
/* dst is a global variable to make testing part easier to check. In real
* production code, a percpu map should be used to store the result.
*/
bpf_dynptr_from_mem(dst, sizeof(dst), 0, &pdst);
/* iv dynptr has to be initialized with 0 size, but proper memory region
* has to be provided anyway
*/
bpf_dynptr_from_mem(dst, 0, 0, &iv);
status = bpf_crypto_encrypt(ctx, &psrc, &pdst, &iv);
return TC_ACT_SHOT;
}
char __license[] SEC("license") = "GPL";
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