mirror of
https://github.com/torvalds/linux.git
synced 2024-12-26 12:52:30 +00:00
251e2d337a
Use bpf_probe_read_user() helper instead of bpf_probe_read() for samples that attach to kprobes probing on user addresses. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/5b0144b3f8e031ec5e2438bd7de8d7877e63bf2f.1572649915.git.daniel@iogearbox.net
54 lines
1.6 KiB
C
54 lines
1.6 KiB
C
/* Copyright (c) 2016 Sargun Dhillon <sargun@sargun.me>
|
|
*
|
|
* This program is free software; you can redistribute it and/or
|
|
* modify it under the terms of version 2 of the GNU General Public
|
|
* License as published by the Free Software Foundation.
|
|
*/
|
|
#include <linux/skbuff.h>
|
|
#include <linux/netdevice.h>
|
|
#include <uapi/linux/bpf.h>
|
|
#include <linux/version.h>
|
|
#include "bpf_helpers.h"
|
|
#include "bpf_tracing.h"
|
|
|
|
struct bpf_map_def SEC("maps") dnat_map = {
|
|
.type = BPF_MAP_TYPE_HASH,
|
|
.key_size = sizeof(struct sockaddr_in),
|
|
.value_size = sizeof(struct sockaddr_in),
|
|
.max_entries = 256,
|
|
};
|
|
|
|
/* kprobe is NOT a stable ABI
|
|
* kernel functions can be removed, renamed or completely change semantics.
|
|
* Number of arguments and their positions can change, etc.
|
|
* In such case this bpf+kprobe example will no longer be meaningful
|
|
*
|
|
* This example sits on a syscall, and the syscall ABI is relatively stable
|
|
* of course, across platforms, and over time, the ABI may change.
|
|
*/
|
|
SEC("kprobe/sys_connect")
|
|
int bpf_prog1(struct pt_regs *ctx)
|
|
{
|
|
struct sockaddr_in new_addr, orig_addr = {};
|
|
struct sockaddr_in *mapped_addr;
|
|
void *sockaddr_arg = (void *)PT_REGS_PARM2(ctx);
|
|
int sockaddr_len = (int)PT_REGS_PARM3(ctx);
|
|
|
|
if (sockaddr_len > sizeof(orig_addr))
|
|
return 0;
|
|
|
|
if (bpf_probe_read_user(&orig_addr, sizeof(orig_addr), sockaddr_arg) != 0)
|
|
return 0;
|
|
|
|
mapped_addr = bpf_map_lookup_elem(&dnat_map, &orig_addr);
|
|
if (mapped_addr != NULL) {
|
|
memcpy(&new_addr, mapped_addr, sizeof(new_addr));
|
|
bpf_probe_write_user(sockaddr_arg, &new_addr,
|
|
sizeof(new_addr));
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
char _license[] SEC("license") = "GPL";
|
|
u32 _version SEC("version") = LINUX_VERSION_CODE;
|