2fde1747c9
Extend original variable-length tests with a case to catch a common existing pattern of testing for < 0 for errors. Note because verifier also tracks upper bounds and we know it can not be greater than MAX_LEN here we can skip upper bound check. In ALU64 enabled compilation converting from long->int return types in probe helpers results in extra instruction pattern, <<= 32, s >>= 32. The trade-off is the non-ALU64 case works. If you really care about every extra insn (XDP case?) then you probably should be using original int type. In addition adding a sext insn to bpf might help the verifier in the general case to avoid these types of tricks. Signed-off-by: John Fastabend <john.fastabend@gmail.com> Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20200623032224.4020118-3-andriin@fb.com
158 lines
3.1 KiB
C
158 lines
3.1 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
/* Copyright (c) 2020 Facebook */
|
|
|
|
#include "vmlinux.h"
|
|
#include <bpf/bpf_helpers.h>
|
|
#include <bpf/bpf_tracing.h>
|
|
#include <bpf/bpf_core_read.h>
|
|
|
|
#define MAX_LEN 256
|
|
|
|
char buf_in1[MAX_LEN] = {};
|
|
char buf_in2[MAX_LEN] = {};
|
|
|
|
int test_pid = 0;
|
|
bool capture = false;
|
|
|
|
/* .bss */
|
|
long payload1_len1 = 0;
|
|
long payload1_len2 = 0;
|
|
long total1 = 0;
|
|
char payload1[MAX_LEN + MAX_LEN] = {};
|
|
|
|
/* .data */
|
|
int payload2_len1 = -1;
|
|
int payload2_len2 = -1;
|
|
int total2 = -1;
|
|
char payload2[MAX_LEN + MAX_LEN] = { 1 };
|
|
|
|
int payload3_len1 = -1;
|
|
int payload3_len2 = -1;
|
|
int total3= -1;
|
|
char payload3[MAX_LEN + MAX_LEN] = { 1 };
|
|
|
|
int payload4_len1 = -1;
|
|
int payload4_len2 = -1;
|
|
int total4= -1;
|
|
char payload4[MAX_LEN + MAX_LEN] = { 1 };
|
|
|
|
SEC("raw_tp/sys_enter")
|
|
int handler64_unsigned(void *regs)
|
|
{
|
|
int pid = bpf_get_current_pid_tgid() >> 32;
|
|
void *payload = payload1;
|
|
u64 len;
|
|
|
|
/* ignore irrelevant invocations */
|
|
if (test_pid != pid || !capture)
|
|
return 0;
|
|
|
|
len = bpf_probe_read_kernel_str(payload, MAX_LEN, &buf_in1[0]);
|
|
if (len <= MAX_LEN) {
|
|
payload += len;
|
|
payload1_len1 = len;
|
|
}
|
|
|
|
len = bpf_probe_read_kernel_str(payload, MAX_LEN, &buf_in2[0]);
|
|
if (len <= MAX_LEN) {
|
|
payload += len;
|
|
payload1_len2 = len;
|
|
}
|
|
|
|
total1 = payload - (void *)payload1;
|
|
|
|
return 0;
|
|
}
|
|
|
|
SEC("raw_tp/sys_exit")
|
|
int handler64_signed(void *regs)
|
|
{
|
|
int pid = bpf_get_current_pid_tgid() >> 32;
|
|
void *payload = payload3;
|
|
long len;
|
|
|
|
/* ignore irrelevant invocations */
|
|
if (test_pid != pid || !capture)
|
|
return 0;
|
|
|
|
len = bpf_probe_read_kernel_str(payload, MAX_LEN, &buf_in1[0]);
|
|
if (len >= 0) {
|
|
payload += len;
|
|
payload3_len1 = len;
|
|
}
|
|
len = bpf_probe_read_kernel_str(payload, MAX_LEN, &buf_in2[0]);
|
|
if (len >= 0) {
|
|
payload += len;
|
|
payload3_len2 = len;
|
|
}
|
|
total3 = payload - (void *)payload3;
|
|
|
|
return 0;
|
|
}
|
|
|
|
SEC("tp/raw_syscalls/sys_enter")
|
|
int handler32_unsigned(void *regs)
|
|
{
|
|
int pid = bpf_get_current_pid_tgid() >> 32;
|
|
void *payload = payload2;
|
|
u32 len;
|
|
|
|
/* ignore irrelevant invocations */
|
|
if (test_pid != pid || !capture)
|
|
return 0;
|
|
|
|
len = bpf_probe_read_kernel_str(payload, MAX_LEN, &buf_in1[0]);
|
|
if (len <= MAX_LEN) {
|
|
payload += len;
|
|
payload2_len1 = len;
|
|
}
|
|
|
|
len = bpf_probe_read_kernel_str(payload, MAX_LEN, &buf_in2[0]);
|
|
if (len <= MAX_LEN) {
|
|
payload += len;
|
|
payload2_len2 = len;
|
|
}
|
|
|
|
total2 = payload - (void *)payload2;
|
|
|
|
return 0;
|
|
}
|
|
|
|
SEC("tp/raw_syscalls/sys_exit")
|
|
int handler32_signed(void *regs)
|
|
{
|
|
int pid = bpf_get_current_pid_tgid() >> 32;
|
|
void *payload = payload4;
|
|
int len;
|
|
|
|
/* ignore irrelevant invocations */
|
|
if (test_pid != pid || !capture)
|
|
return 0;
|
|
|
|
len = bpf_probe_read_kernel_str(payload, MAX_LEN, &buf_in1[0]);
|
|
if (len >= 0) {
|
|
payload += len;
|
|
payload4_len1 = len;
|
|
}
|
|
len = bpf_probe_read_kernel_str(payload, MAX_LEN, &buf_in2[0]);
|
|
if (len >= 0) {
|
|
payload += len;
|
|
payload4_len2 = len;
|
|
}
|
|
total4 = payload - (void *)payload4;
|
|
|
|
return 0;
|
|
}
|
|
|
|
SEC("tp/syscalls/sys_exit_getpid")
|
|
int handler_exit(void *regs)
|
|
{
|
|
long bla;
|
|
|
|
if (bpf_probe_read_kernel(&bla, sizeof(bla), 0))
|
|
return 1;
|
|
else
|
|
return 0;
|
|
}
|
|
|
|
char LICENSE[] SEC("license") = "GPL";
|