forked from Minki/linux
8e7a3920ac
Split the bpf_perf_event_output() helper as a preparation into two parts. The new bpf_perf_event_output() will prepare the raw record itself and test for unknown flags from BPF trace context, where the __bpf_perf_event_output() does the core work. The latter will be reused later on from bpf_event_output() directly. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
486 lines
12 KiB
C
486 lines
12 KiB
C
/* Copyright (c) 2011-2015 PLUMgrid, http://plumgrid.com
|
|
*
|
|
* 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/kernel.h>
|
|
#include <linux/types.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/bpf.h>
|
|
#include <linux/filter.h>
|
|
#include <linux/uaccess.h>
|
|
#include <linux/ctype.h>
|
|
#include "trace.h"
|
|
|
|
/**
|
|
* trace_call_bpf - invoke BPF program
|
|
* @prog: BPF program
|
|
* @ctx: opaque context pointer
|
|
*
|
|
* kprobe handlers execute BPF programs via this helper.
|
|
* Can be used from static tracepoints in the future.
|
|
*
|
|
* Return: BPF programs always return an integer which is interpreted by
|
|
* kprobe handler as:
|
|
* 0 - return from kprobe (event is filtered out)
|
|
* 1 - store kprobe event into ring buffer
|
|
* Other values are reserved and currently alias to 1
|
|
*/
|
|
unsigned int trace_call_bpf(struct bpf_prog *prog, void *ctx)
|
|
{
|
|
unsigned int ret;
|
|
|
|
if (in_nmi()) /* not supported yet */
|
|
return 1;
|
|
|
|
preempt_disable();
|
|
|
|
if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1)) {
|
|
/*
|
|
* since some bpf program is already running on this cpu,
|
|
* don't call into another bpf program (same or different)
|
|
* and don't send kprobe event into ring-buffer,
|
|
* so return zero here
|
|
*/
|
|
ret = 0;
|
|
goto out;
|
|
}
|
|
|
|
rcu_read_lock();
|
|
ret = BPF_PROG_RUN(prog, ctx);
|
|
rcu_read_unlock();
|
|
|
|
out:
|
|
__this_cpu_dec(bpf_prog_active);
|
|
preempt_enable();
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(trace_call_bpf);
|
|
|
|
static u64 bpf_probe_read(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
|
|
{
|
|
void *dst = (void *) (long) r1;
|
|
int ret, size = (int) r2;
|
|
void *unsafe_ptr = (void *) (long) r3;
|
|
|
|
ret = probe_kernel_read(dst, unsafe_ptr, size);
|
|
if (unlikely(ret < 0))
|
|
memset(dst, 0, size);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static const struct bpf_func_proto bpf_probe_read_proto = {
|
|
.func = bpf_probe_read,
|
|
.gpl_only = true,
|
|
.ret_type = RET_INTEGER,
|
|
.arg1_type = ARG_PTR_TO_RAW_STACK,
|
|
.arg2_type = ARG_CONST_STACK_SIZE,
|
|
.arg3_type = ARG_ANYTHING,
|
|
};
|
|
|
|
/*
|
|
* limited trace_printk()
|
|
* only %d %u %x %ld %lu %lx %lld %llu %llx %p %s conversion specifiers allowed
|
|
*/
|
|
static u64 bpf_trace_printk(u64 r1, u64 fmt_size, u64 r3, u64 r4, u64 r5)
|
|
{
|
|
char *fmt = (char *) (long) r1;
|
|
bool str_seen = false;
|
|
int mod[3] = {};
|
|
int fmt_cnt = 0;
|
|
u64 unsafe_addr;
|
|
char buf[64];
|
|
int i;
|
|
|
|
/*
|
|
* bpf_check()->check_func_arg()->check_stack_boundary()
|
|
* guarantees that fmt points to bpf program stack,
|
|
* fmt_size bytes of it were initialized and fmt_size > 0
|
|
*/
|
|
if (fmt[--fmt_size] != 0)
|
|
return -EINVAL;
|
|
|
|
/* check format string for allowed specifiers */
|
|
for (i = 0; i < fmt_size; i++) {
|
|
if ((!isprint(fmt[i]) && !isspace(fmt[i])) || !isascii(fmt[i]))
|
|
return -EINVAL;
|
|
|
|
if (fmt[i] != '%')
|
|
continue;
|
|
|
|
if (fmt_cnt >= 3)
|
|
return -EINVAL;
|
|
|
|
/* fmt[i] != 0 && fmt[last] == 0, so we can access fmt[i + 1] */
|
|
i++;
|
|
if (fmt[i] == 'l') {
|
|
mod[fmt_cnt]++;
|
|
i++;
|
|
} else if (fmt[i] == 'p' || fmt[i] == 's') {
|
|
mod[fmt_cnt]++;
|
|
i++;
|
|
if (!isspace(fmt[i]) && !ispunct(fmt[i]) && fmt[i] != 0)
|
|
return -EINVAL;
|
|
fmt_cnt++;
|
|
if (fmt[i - 1] == 's') {
|
|
if (str_seen)
|
|
/* allow only one '%s' per fmt string */
|
|
return -EINVAL;
|
|
str_seen = true;
|
|
|
|
switch (fmt_cnt) {
|
|
case 1:
|
|
unsafe_addr = r3;
|
|
r3 = (long) buf;
|
|
break;
|
|
case 2:
|
|
unsafe_addr = r4;
|
|
r4 = (long) buf;
|
|
break;
|
|
case 3:
|
|
unsafe_addr = r5;
|
|
r5 = (long) buf;
|
|
break;
|
|
}
|
|
buf[0] = 0;
|
|
strncpy_from_unsafe(buf,
|
|
(void *) (long) unsafe_addr,
|
|
sizeof(buf));
|
|
}
|
|
continue;
|
|
}
|
|
|
|
if (fmt[i] == 'l') {
|
|
mod[fmt_cnt]++;
|
|
i++;
|
|
}
|
|
|
|
if (fmt[i] != 'd' && fmt[i] != 'u' && fmt[i] != 'x')
|
|
return -EINVAL;
|
|
fmt_cnt++;
|
|
}
|
|
|
|
return __trace_printk(1/* fake ip will not be printed */, fmt,
|
|
mod[0] == 2 ? r3 : mod[0] == 1 ? (long) r3 : (u32) r3,
|
|
mod[1] == 2 ? r4 : mod[1] == 1 ? (long) r4 : (u32) r4,
|
|
mod[2] == 2 ? r5 : mod[2] == 1 ? (long) r5 : (u32) r5);
|
|
}
|
|
|
|
static const struct bpf_func_proto bpf_trace_printk_proto = {
|
|
.func = bpf_trace_printk,
|
|
.gpl_only = true,
|
|
.ret_type = RET_INTEGER,
|
|
.arg1_type = ARG_PTR_TO_STACK,
|
|
.arg2_type = ARG_CONST_STACK_SIZE,
|
|
};
|
|
|
|
const struct bpf_func_proto *bpf_get_trace_printk_proto(void)
|
|
{
|
|
/*
|
|
* this program might be calling bpf_trace_printk,
|
|
* so allocate per-cpu printk buffers
|
|
*/
|
|
trace_printk_init_buffers();
|
|
|
|
return &bpf_trace_printk_proto;
|
|
}
|
|
|
|
static u64 bpf_perf_event_read(u64 r1, u64 flags, u64 r3, u64 r4, u64 r5)
|
|
{
|
|
struct bpf_map *map = (struct bpf_map *) (unsigned long) r1;
|
|
struct bpf_array *array = container_of(map, struct bpf_array, map);
|
|
unsigned int cpu = smp_processor_id();
|
|
u64 index = flags & BPF_F_INDEX_MASK;
|
|
struct bpf_event_entry *ee;
|
|
struct perf_event *event;
|
|
|
|
if (unlikely(flags & ~(BPF_F_INDEX_MASK)))
|
|
return -EINVAL;
|
|
if (index == BPF_F_CURRENT_CPU)
|
|
index = cpu;
|
|
if (unlikely(index >= array->map.max_entries))
|
|
return -E2BIG;
|
|
|
|
ee = READ_ONCE(array->ptrs[index]);
|
|
if (!ee)
|
|
return -ENOENT;
|
|
|
|
event = ee->event;
|
|
if (unlikely(event->attr.type != PERF_TYPE_HARDWARE &&
|
|
event->attr.type != PERF_TYPE_RAW))
|
|
return -EINVAL;
|
|
|
|
/* make sure event is local and doesn't have pmu::count */
|
|
if (unlikely(event->oncpu != cpu || event->pmu->count))
|
|
return -EINVAL;
|
|
|
|
/*
|
|
* we don't know if the function is run successfully by the
|
|
* return value. It can be judged in other places, such as
|
|
* eBPF programs.
|
|
*/
|
|
return perf_event_read_local(event);
|
|
}
|
|
|
|
static const struct bpf_func_proto bpf_perf_event_read_proto = {
|
|
.func = bpf_perf_event_read,
|
|
.gpl_only = true,
|
|
.ret_type = RET_INTEGER,
|
|
.arg1_type = ARG_CONST_MAP_PTR,
|
|
.arg2_type = ARG_ANYTHING,
|
|
};
|
|
|
|
static __always_inline u64
|
|
__bpf_perf_event_output(struct pt_regs *regs, struct bpf_map *map,
|
|
u64 flags, struct perf_raw_record *raw)
|
|
{
|
|
struct bpf_array *array = container_of(map, struct bpf_array, map);
|
|
unsigned int cpu = smp_processor_id();
|
|
u64 index = flags & BPF_F_INDEX_MASK;
|
|
struct perf_sample_data sample_data;
|
|
struct bpf_event_entry *ee;
|
|
struct perf_event *event;
|
|
|
|
if (index == BPF_F_CURRENT_CPU)
|
|
index = cpu;
|
|
if (unlikely(index >= array->map.max_entries))
|
|
return -E2BIG;
|
|
|
|
ee = READ_ONCE(array->ptrs[index]);
|
|
if (!ee)
|
|
return -ENOENT;
|
|
|
|
event = ee->event;
|
|
if (unlikely(event->attr.type != PERF_TYPE_SOFTWARE ||
|
|
event->attr.config != PERF_COUNT_SW_BPF_OUTPUT))
|
|
return -EINVAL;
|
|
|
|
if (unlikely(event->oncpu != cpu))
|
|
return -EOPNOTSUPP;
|
|
|
|
perf_sample_data_init(&sample_data, 0, 0);
|
|
sample_data.raw = raw;
|
|
perf_event_output(event, &sample_data, regs);
|
|
return 0;
|
|
}
|
|
|
|
static u64 bpf_perf_event_output(u64 r1, u64 r2, u64 flags, u64 r4, u64 size)
|
|
{
|
|
struct pt_regs *regs = (struct pt_regs *)(long) r1;
|
|
struct bpf_map *map = (struct bpf_map *)(long) r2;
|
|
void *data = (void *)(long) r4;
|
|
struct perf_raw_record raw = {
|
|
.frag = {
|
|
.size = size,
|
|
.data = data,
|
|
},
|
|
};
|
|
|
|
if (unlikely(flags & ~(BPF_F_INDEX_MASK)))
|
|
return -EINVAL;
|
|
|
|
return __bpf_perf_event_output(regs, map, flags, &raw);
|
|
}
|
|
|
|
static const struct bpf_func_proto bpf_perf_event_output_proto = {
|
|
.func = bpf_perf_event_output,
|
|
.gpl_only = true,
|
|
.ret_type = RET_INTEGER,
|
|
.arg1_type = ARG_PTR_TO_CTX,
|
|
.arg2_type = ARG_CONST_MAP_PTR,
|
|
.arg3_type = ARG_ANYTHING,
|
|
.arg4_type = ARG_PTR_TO_STACK,
|
|
.arg5_type = ARG_CONST_STACK_SIZE,
|
|
};
|
|
|
|
static DEFINE_PER_CPU(struct pt_regs, bpf_pt_regs);
|
|
|
|
static u64 bpf_event_output(u64 r1, u64 r2, u64 flags, u64 r4, u64 size)
|
|
{
|
|
struct pt_regs *regs = this_cpu_ptr(&bpf_pt_regs);
|
|
|
|
perf_fetch_caller_regs(regs);
|
|
|
|
return bpf_perf_event_output((long)regs, r2, flags, r4, size);
|
|
}
|
|
|
|
static const struct bpf_func_proto bpf_event_output_proto = {
|
|
.func = bpf_event_output,
|
|
.gpl_only = true,
|
|
.ret_type = RET_INTEGER,
|
|
.arg1_type = ARG_PTR_TO_CTX,
|
|
.arg2_type = ARG_CONST_MAP_PTR,
|
|
.arg3_type = ARG_ANYTHING,
|
|
.arg4_type = ARG_PTR_TO_STACK,
|
|
.arg5_type = ARG_CONST_STACK_SIZE,
|
|
};
|
|
|
|
const struct bpf_func_proto *bpf_get_event_output_proto(void)
|
|
{
|
|
return &bpf_event_output_proto;
|
|
}
|
|
|
|
static u64 bpf_get_current_task(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
|
|
{
|
|
return (long) current;
|
|
}
|
|
|
|
static const struct bpf_func_proto bpf_get_current_task_proto = {
|
|
.func = bpf_get_current_task,
|
|
.gpl_only = true,
|
|
.ret_type = RET_INTEGER,
|
|
};
|
|
|
|
static const struct bpf_func_proto *tracing_func_proto(enum bpf_func_id func_id)
|
|
{
|
|
switch (func_id) {
|
|
case BPF_FUNC_map_lookup_elem:
|
|
return &bpf_map_lookup_elem_proto;
|
|
case BPF_FUNC_map_update_elem:
|
|
return &bpf_map_update_elem_proto;
|
|
case BPF_FUNC_map_delete_elem:
|
|
return &bpf_map_delete_elem_proto;
|
|
case BPF_FUNC_probe_read:
|
|
return &bpf_probe_read_proto;
|
|
case BPF_FUNC_ktime_get_ns:
|
|
return &bpf_ktime_get_ns_proto;
|
|
case BPF_FUNC_tail_call:
|
|
return &bpf_tail_call_proto;
|
|
case BPF_FUNC_get_current_pid_tgid:
|
|
return &bpf_get_current_pid_tgid_proto;
|
|
case BPF_FUNC_get_current_task:
|
|
return &bpf_get_current_task_proto;
|
|
case BPF_FUNC_get_current_uid_gid:
|
|
return &bpf_get_current_uid_gid_proto;
|
|
case BPF_FUNC_get_current_comm:
|
|
return &bpf_get_current_comm_proto;
|
|
case BPF_FUNC_trace_printk:
|
|
return bpf_get_trace_printk_proto();
|
|
case BPF_FUNC_get_smp_processor_id:
|
|
return &bpf_get_smp_processor_id_proto;
|
|
case BPF_FUNC_perf_event_read:
|
|
return &bpf_perf_event_read_proto;
|
|
default:
|
|
return NULL;
|
|
}
|
|
}
|
|
|
|
static const struct bpf_func_proto *kprobe_prog_func_proto(enum bpf_func_id func_id)
|
|
{
|
|
switch (func_id) {
|
|
case BPF_FUNC_perf_event_output:
|
|
return &bpf_perf_event_output_proto;
|
|
case BPF_FUNC_get_stackid:
|
|
return &bpf_get_stackid_proto;
|
|
default:
|
|
return tracing_func_proto(func_id);
|
|
}
|
|
}
|
|
|
|
/* bpf+kprobe programs can access fields of 'struct pt_regs' */
|
|
static bool kprobe_prog_is_valid_access(int off, int size, enum bpf_access_type type,
|
|
enum bpf_reg_type *reg_type)
|
|
{
|
|
if (off < 0 || off >= sizeof(struct pt_regs))
|
|
return false;
|
|
if (type != BPF_READ)
|
|
return false;
|
|
if (off % size != 0)
|
|
return false;
|
|
return true;
|
|
}
|
|
|
|
static const struct bpf_verifier_ops kprobe_prog_ops = {
|
|
.get_func_proto = kprobe_prog_func_proto,
|
|
.is_valid_access = kprobe_prog_is_valid_access,
|
|
};
|
|
|
|
static struct bpf_prog_type_list kprobe_tl = {
|
|
.ops = &kprobe_prog_ops,
|
|
.type = BPF_PROG_TYPE_KPROBE,
|
|
};
|
|
|
|
static u64 bpf_perf_event_output_tp(u64 r1, u64 r2, u64 index, u64 r4, u64 size)
|
|
{
|
|
/*
|
|
* r1 points to perf tracepoint buffer where first 8 bytes are hidden
|
|
* from bpf program and contain a pointer to 'struct pt_regs'. Fetch it
|
|
* from there and call the same bpf_perf_event_output() helper
|
|
*/
|
|
u64 ctx = *(long *)(uintptr_t)r1;
|
|
|
|
return bpf_perf_event_output(ctx, r2, index, r4, size);
|
|
}
|
|
|
|
static const struct bpf_func_proto bpf_perf_event_output_proto_tp = {
|
|
.func = bpf_perf_event_output_tp,
|
|
.gpl_only = true,
|
|
.ret_type = RET_INTEGER,
|
|
.arg1_type = ARG_PTR_TO_CTX,
|
|
.arg2_type = ARG_CONST_MAP_PTR,
|
|
.arg3_type = ARG_ANYTHING,
|
|
.arg4_type = ARG_PTR_TO_STACK,
|
|
.arg5_type = ARG_CONST_STACK_SIZE,
|
|
};
|
|
|
|
static u64 bpf_get_stackid_tp(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
|
|
{
|
|
u64 ctx = *(long *)(uintptr_t)r1;
|
|
|
|
return bpf_get_stackid(ctx, r2, r3, r4, r5);
|
|
}
|
|
|
|
static const struct bpf_func_proto bpf_get_stackid_proto_tp = {
|
|
.func = bpf_get_stackid_tp,
|
|
.gpl_only = true,
|
|
.ret_type = RET_INTEGER,
|
|
.arg1_type = ARG_PTR_TO_CTX,
|
|
.arg2_type = ARG_CONST_MAP_PTR,
|
|
.arg3_type = ARG_ANYTHING,
|
|
};
|
|
|
|
static const struct bpf_func_proto *tp_prog_func_proto(enum bpf_func_id func_id)
|
|
{
|
|
switch (func_id) {
|
|
case BPF_FUNC_perf_event_output:
|
|
return &bpf_perf_event_output_proto_tp;
|
|
case BPF_FUNC_get_stackid:
|
|
return &bpf_get_stackid_proto_tp;
|
|
default:
|
|
return tracing_func_proto(func_id);
|
|
}
|
|
}
|
|
|
|
static bool tp_prog_is_valid_access(int off, int size, enum bpf_access_type type,
|
|
enum bpf_reg_type *reg_type)
|
|
{
|
|
if (off < sizeof(void *) || off >= PERF_MAX_TRACE_SIZE)
|
|
return false;
|
|
if (type != BPF_READ)
|
|
return false;
|
|
if (off % size != 0)
|
|
return false;
|
|
return true;
|
|
}
|
|
|
|
static const struct bpf_verifier_ops tracepoint_prog_ops = {
|
|
.get_func_proto = tp_prog_func_proto,
|
|
.is_valid_access = tp_prog_is_valid_access,
|
|
};
|
|
|
|
static struct bpf_prog_type_list tracepoint_tl = {
|
|
.ops = &tracepoint_prog_ops,
|
|
.type = BPF_PROG_TYPE_TRACEPOINT,
|
|
};
|
|
|
|
static int __init register_kprobe_prog_ops(void)
|
|
{
|
|
bpf_register_prog_type(&kprobe_tl);
|
|
bpf_register_prog_type(&tracepoint_tl);
|
|
return 0;
|
|
}
|
|
late_initcall(register_kprobe_prog_ops);
|