forked from Minki/linux
f005afede9
Commit4bebdc7a85
("bpf: add helper bpf_perf_prog_read_value") added helper bpf_perf_prog_read_value so that perf_event type program can read event counter and enabled/running time. This commit, however, introduced a bug which allows this helper for tracepoint type programs. This is incorrect as bpf_perf_prog_read_value needs to access perf_event through its bpf_perf_event_data_kern type context, which is not available for tracepoint type program. This patch fixed the issue by separating bpf_func_proto between tracepoint and perf_event type programs and removed bpf_perf_prog_read_value from tracepoint func prototype. Fixes:4bebdc7a85
("bpf: add helper bpf_perf_prog_read_value") Reported-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
899 lines
24 KiB
C
899 lines
24 KiB
C
/* Copyright (c) 2011-2015 PLUMgrid, http://plumgrid.com
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* Copyright (c) 2016 Facebook
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of version 2 of the GNU General Public
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* License as published by the Free Software Foundation.
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*/
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#include <linux/kernel.h>
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#include <linux/types.h>
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#include <linux/slab.h>
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#include <linux/bpf.h>
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#include <linux/bpf_perf_event.h>
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#include <linux/filter.h>
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#include <linux/uaccess.h>
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#include <linux/ctype.h>
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#include <linux/kprobes.h>
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#include <linux/error-injection.h>
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#include "trace_probe.h"
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#include "trace.h"
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u64 bpf_get_stackid(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
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/**
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* trace_call_bpf - invoke BPF program
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* @call: tracepoint event
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* @ctx: opaque context pointer
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*
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* kprobe handlers execute BPF programs via this helper.
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* Can be used from static tracepoints in the future.
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*
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* Return: BPF programs always return an integer which is interpreted by
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* kprobe handler as:
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* 0 - return from kprobe (event is filtered out)
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* 1 - store kprobe event into ring buffer
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* Other values are reserved and currently alias to 1
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*/
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unsigned int trace_call_bpf(struct trace_event_call *call, void *ctx)
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{
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unsigned int ret;
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if (in_nmi()) /* not supported yet */
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return 1;
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preempt_disable();
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if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1)) {
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/*
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* since some bpf program is already running on this cpu,
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* don't call into another bpf program (same or different)
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* and don't send kprobe event into ring-buffer,
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* so return zero here
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*/
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ret = 0;
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goto out;
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}
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/*
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* Instead of moving rcu_read_lock/rcu_dereference/rcu_read_unlock
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* to all call sites, we did a bpf_prog_array_valid() there to check
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* whether call->prog_array is empty or not, which is
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* a heurisitc to speed up execution.
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*
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* If bpf_prog_array_valid() fetched prog_array was
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* non-NULL, we go into trace_call_bpf() and do the actual
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* proper rcu_dereference() under RCU lock.
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* If it turns out that prog_array is NULL then, we bail out.
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* For the opposite, if the bpf_prog_array_valid() fetched pointer
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* was NULL, you'll skip the prog_array with the risk of missing
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* out of events when it was updated in between this and the
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* rcu_dereference() which is accepted risk.
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*/
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ret = BPF_PROG_RUN_ARRAY_CHECK(call->prog_array, ctx, BPF_PROG_RUN);
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out:
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__this_cpu_dec(bpf_prog_active);
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preempt_enable();
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return ret;
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}
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EXPORT_SYMBOL_GPL(trace_call_bpf);
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#ifdef CONFIG_BPF_KPROBE_OVERRIDE
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BPF_CALL_2(bpf_override_return, struct pt_regs *, regs, unsigned long, rc)
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{
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regs_set_return_value(regs, rc);
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override_function_with_return(regs);
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return 0;
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}
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static const struct bpf_func_proto bpf_override_return_proto = {
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.func = bpf_override_return,
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.gpl_only = true,
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.ret_type = RET_INTEGER,
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.arg1_type = ARG_PTR_TO_CTX,
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.arg2_type = ARG_ANYTHING,
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};
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#endif
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BPF_CALL_3(bpf_probe_read, void *, dst, u32, size, const void *, unsafe_ptr)
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{
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int ret;
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ret = probe_kernel_read(dst, unsafe_ptr, size);
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if (unlikely(ret < 0))
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memset(dst, 0, size);
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return ret;
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}
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static const struct bpf_func_proto bpf_probe_read_proto = {
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.func = bpf_probe_read,
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.gpl_only = true,
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.ret_type = RET_INTEGER,
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.arg1_type = ARG_PTR_TO_UNINIT_MEM,
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.arg2_type = ARG_CONST_SIZE_OR_ZERO,
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.arg3_type = ARG_ANYTHING,
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};
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BPF_CALL_3(bpf_probe_write_user, void *, unsafe_ptr, const void *, src,
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u32, size)
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{
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/*
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* Ensure we're in user context which is safe for the helper to
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* run. This helper has no business in a kthread.
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*
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* access_ok() should prevent writing to non-user memory, but in
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* some situations (nommu, temporary switch, etc) access_ok() does
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* not provide enough validation, hence the check on KERNEL_DS.
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*/
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if (unlikely(in_interrupt() ||
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current->flags & (PF_KTHREAD | PF_EXITING)))
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return -EPERM;
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if (unlikely(uaccess_kernel()))
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return -EPERM;
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if (!access_ok(VERIFY_WRITE, unsafe_ptr, size))
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return -EPERM;
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return probe_kernel_write(unsafe_ptr, src, size);
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}
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static const struct bpf_func_proto bpf_probe_write_user_proto = {
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.func = bpf_probe_write_user,
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.gpl_only = true,
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.ret_type = RET_INTEGER,
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.arg1_type = ARG_ANYTHING,
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.arg2_type = ARG_PTR_TO_MEM,
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.arg3_type = ARG_CONST_SIZE,
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};
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static const struct bpf_func_proto *bpf_get_probe_write_proto(void)
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{
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pr_warn_ratelimited("%s[%d] is installing a program with bpf_probe_write_user helper that may corrupt user memory!",
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current->comm, task_pid_nr(current));
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return &bpf_probe_write_user_proto;
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}
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/*
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* Only limited trace_printk() conversion specifiers allowed:
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* %d %i %u %x %ld %li %lu %lx %lld %lli %llu %llx %p %s
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*/
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BPF_CALL_5(bpf_trace_printk, char *, fmt, u32, fmt_size, u64, arg1,
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u64, arg2, u64, arg3)
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{
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bool str_seen = false;
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int mod[3] = {};
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int fmt_cnt = 0;
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u64 unsafe_addr;
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char buf[64];
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int i;
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/*
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* bpf_check()->check_func_arg()->check_stack_boundary()
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* guarantees that fmt points to bpf program stack,
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* fmt_size bytes of it were initialized and fmt_size > 0
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*/
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if (fmt[--fmt_size] != 0)
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return -EINVAL;
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/* check format string for allowed specifiers */
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for (i = 0; i < fmt_size; i++) {
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if ((!isprint(fmt[i]) && !isspace(fmt[i])) || !isascii(fmt[i]))
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return -EINVAL;
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if (fmt[i] != '%')
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continue;
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if (fmt_cnt >= 3)
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return -EINVAL;
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/* fmt[i] != 0 && fmt[last] == 0, so we can access fmt[i + 1] */
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i++;
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if (fmt[i] == 'l') {
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mod[fmt_cnt]++;
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i++;
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} else if (fmt[i] == 'p' || fmt[i] == 's') {
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mod[fmt_cnt]++;
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i++;
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if (!isspace(fmt[i]) && !ispunct(fmt[i]) && fmt[i] != 0)
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return -EINVAL;
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fmt_cnt++;
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if (fmt[i - 1] == 's') {
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if (str_seen)
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/* allow only one '%s' per fmt string */
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return -EINVAL;
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str_seen = true;
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switch (fmt_cnt) {
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case 1:
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unsafe_addr = arg1;
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arg1 = (long) buf;
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break;
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case 2:
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unsafe_addr = arg2;
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arg2 = (long) buf;
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break;
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case 3:
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unsafe_addr = arg3;
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arg3 = (long) buf;
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break;
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}
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buf[0] = 0;
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strncpy_from_unsafe(buf,
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(void *) (long) unsafe_addr,
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sizeof(buf));
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}
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continue;
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}
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if (fmt[i] == 'l') {
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mod[fmt_cnt]++;
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i++;
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}
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if (fmt[i] != 'i' && fmt[i] != 'd' &&
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fmt[i] != 'u' && fmt[i] != 'x')
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return -EINVAL;
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fmt_cnt++;
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}
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/* Horrid workaround for getting va_list handling working with different
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* argument type combinations generically for 32 and 64 bit archs.
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*/
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#define __BPF_TP_EMIT() __BPF_ARG3_TP()
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#define __BPF_TP(...) \
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__trace_printk(0 /* Fake ip */, \
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fmt, ##__VA_ARGS__)
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#define __BPF_ARG1_TP(...) \
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((mod[0] == 2 || (mod[0] == 1 && __BITS_PER_LONG == 64)) \
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? __BPF_TP(arg1, ##__VA_ARGS__) \
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: ((mod[0] == 1 || (mod[0] == 0 && __BITS_PER_LONG == 32)) \
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? __BPF_TP((long)arg1, ##__VA_ARGS__) \
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: __BPF_TP((u32)arg1, ##__VA_ARGS__)))
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#define __BPF_ARG2_TP(...) \
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((mod[1] == 2 || (mod[1] == 1 && __BITS_PER_LONG == 64)) \
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? __BPF_ARG1_TP(arg2, ##__VA_ARGS__) \
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: ((mod[1] == 1 || (mod[1] == 0 && __BITS_PER_LONG == 32)) \
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? __BPF_ARG1_TP((long)arg2, ##__VA_ARGS__) \
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: __BPF_ARG1_TP((u32)arg2, ##__VA_ARGS__)))
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#define __BPF_ARG3_TP(...) \
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((mod[2] == 2 || (mod[2] == 1 && __BITS_PER_LONG == 64)) \
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? __BPF_ARG2_TP(arg3, ##__VA_ARGS__) \
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: ((mod[2] == 1 || (mod[2] == 0 && __BITS_PER_LONG == 32)) \
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? __BPF_ARG2_TP((long)arg3, ##__VA_ARGS__) \
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: __BPF_ARG2_TP((u32)arg3, ##__VA_ARGS__)))
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return __BPF_TP_EMIT();
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}
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static const struct bpf_func_proto bpf_trace_printk_proto = {
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.func = bpf_trace_printk,
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.gpl_only = true,
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.ret_type = RET_INTEGER,
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.arg1_type = ARG_PTR_TO_MEM,
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.arg2_type = ARG_CONST_SIZE,
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};
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const struct bpf_func_proto *bpf_get_trace_printk_proto(void)
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{
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/*
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* this program might be calling bpf_trace_printk,
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* so allocate per-cpu printk buffers
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*/
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trace_printk_init_buffers();
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return &bpf_trace_printk_proto;
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}
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static __always_inline int
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get_map_perf_counter(struct bpf_map *map, u64 flags,
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u64 *value, u64 *enabled, u64 *running)
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{
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struct bpf_array *array = container_of(map, struct bpf_array, map);
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unsigned int cpu = smp_processor_id();
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u64 index = flags & BPF_F_INDEX_MASK;
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struct bpf_event_entry *ee;
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if (unlikely(flags & ~(BPF_F_INDEX_MASK)))
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return -EINVAL;
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if (index == BPF_F_CURRENT_CPU)
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index = cpu;
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if (unlikely(index >= array->map.max_entries))
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return -E2BIG;
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ee = READ_ONCE(array->ptrs[index]);
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if (!ee)
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return -ENOENT;
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return perf_event_read_local(ee->event, value, enabled, running);
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}
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BPF_CALL_2(bpf_perf_event_read, struct bpf_map *, map, u64, flags)
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{
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u64 value = 0;
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int err;
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err = get_map_perf_counter(map, flags, &value, NULL, NULL);
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/*
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* this api is ugly since we miss [-22..-2] range of valid
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* counter values, but that's uapi
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*/
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if (err)
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return err;
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return value;
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}
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static const struct bpf_func_proto bpf_perf_event_read_proto = {
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.func = bpf_perf_event_read,
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.gpl_only = true,
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.ret_type = RET_INTEGER,
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.arg1_type = ARG_CONST_MAP_PTR,
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.arg2_type = ARG_ANYTHING,
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};
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BPF_CALL_4(bpf_perf_event_read_value, struct bpf_map *, map, u64, flags,
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struct bpf_perf_event_value *, buf, u32, size)
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{
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int err = -EINVAL;
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if (unlikely(size != sizeof(struct bpf_perf_event_value)))
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goto clear;
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err = get_map_perf_counter(map, flags, &buf->counter, &buf->enabled,
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&buf->running);
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if (unlikely(err))
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goto clear;
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return 0;
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clear:
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memset(buf, 0, size);
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return err;
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}
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static const struct bpf_func_proto bpf_perf_event_read_value_proto = {
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.func = bpf_perf_event_read_value,
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.gpl_only = true,
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.ret_type = RET_INTEGER,
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.arg1_type = ARG_CONST_MAP_PTR,
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.arg2_type = ARG_ANYTHING,
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.arg3_type = ARG_PTR_TO_UNINIT_MEM,
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.arg4_type = ARG_CONST_SIZE,
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};
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static DEFINE_PER_CPU(struct perf_sample_data, bpf_trace_sd);
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static __always_inline u64
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__bpf_perf_event_output(struct pt_regs *regs, struct bpf_map *map,
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u64 flags, struct perf_sample_data *sd)
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{
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struct bpf_array *array = container_of(map, struct bpf_array, map);
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unsigned int cpu = smp_processor_id();
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u64 index = flags & BPF_F_INDEX_MASK;
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struct bpf_event_entry *ee;
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struct perf_event *event;
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if (index == BPF_F_CURRENT_CPU)
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index = cpu;
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if (unlikely(index >= array->map.max_entries))
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return -E2BIG;
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ee = READ_ONCE(array->ptrs[index]);
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if (!ee)
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return -ENOENT;
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event = ee->event;
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if (unlikely(event->attr.type != PERF_TYPE_SOFTWARE ||
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event->attr.config != PERF_COUNT_SW_BPF_OUTPUT))
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return -EINVAL;
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if (unlikely(event->oncpu != cpu))
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return -EOPNOTSUPP;
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perf_event_output(event, sd, regs);
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return 0;
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}
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BPF_CALL_5(bpf_perf_event_output, struct pt_regs *, regs, struct bpf_map *, map,
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u64, flags, void *, data, u64, size)
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{
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struct perf_sample_data *sd = this_cpu_ptr(&bpf_trace_sd);
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struct perf_raw_record raw = {
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.frag = {
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.size = size,
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.data = data,
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},
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};
|
|
|
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if (unlikely(flags & ~(BPF_F_INDEX_MASK)))
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return -EINVAL;
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|
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perf_sample_data_init(sd, 0, 0);
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sd->raw = &raw;
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return __bpf_perf_event_output(regs, map, flags, sd);
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}
|
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|
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static const struct bpf_func_proto bpf_perf_event_output_proto = {
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.func = bpf_perf_event_output,
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.gpl_only = true,
|
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.ret_type = RET_INTEGER,
|
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.arg1_type = ARG_PTR_TO_CTX,
|
|
.arg2_type = ARG_CONST_MAP_PTR,
|
|
.arg3_type = ARG_ANYTHING,
|
|
.arg4_type = ARG_PTR_TO_MEM,
|
|
.arg5_type = ARG_CONST_SIZE_OR_ZERO,
|
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};
|
|
|
|
static DEFINE_PER_CPU(struct pt_regs, bpf_pt_regs);
|
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static DEFINE_PER_CPU(struct perf_sample_data, bpf_misc_sd);
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|
|
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u64 bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size,
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|
void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy)
|
|
{
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|
struct perf_sample_data *sd = this_cpu_ptr(&bpf_misc_sd);
|
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struct pt_regs *regs = this_cpu_ptr(&bpf_pt_regs);
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struct perf_raw_frag frag = {
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.copy = ctx_copy,
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.size = ctx_size,
|
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.data = ctx,
|
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};
|
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struct perf_raw_record raw = {
|
|
.frag = {
|
|
{
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.next = ctx_size ? &frag : NULL,
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},
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.size = meta_size,
|
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.data = meta,
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},
|
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};
|
|
|
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perf_fetch_caller_regs(regs);
|
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perf_sample_data_init(sd, 0, 0);
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sd->raw = &raw;
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|
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return __bpf_perf_event_output(regs, map, flags, sd);
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}
|
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|
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BPF_CALL_0(bpf_get_current_task)
|
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{
|
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return (long) current;
|
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}
|
|
|
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static const struct bpf_func_proto bpf_get_current_task_proto = {
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.func = bpf_get_current_task,
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.gpl_only = true,
|
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.ret_type = RET_INTEGER,
|
|
};
|
|
|
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BPF_CALL_2(bpf_current_task_under_cgroup, struct bpf_map *, map, u32, idx)
|
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{
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|
struct bpf_array *array = container_of(map, struct bpf_array, map);
|
|
struct cgroup *cgrp;
|
|
|
|
if (unlikely(in_interrupt()))
|
|
return -EINVAL;
|
|
if (unlikely(idx >= array->map.max_entries))
|
|
return -E2BIG;
|
|
|
|
cgrp = READ_ONCE(array->ptrs[idx]);
|
|
if (unlikely(!cgrp))
|
|
return -EAGAIN;
|
|
|
|
return task_under_cgroup_hierarchy(current, cgrp);
|
|
}
|
|
|
|
static const struct bpf_func_proto bpf_current_task_under_cgroup_proto = {
|
|
.func = bpf_current_task_under_cgroup,
|
|
.gpl_only = false,
|
|
.ret_type = RET_INTEGER,
|
|
.arg1_type = ARG_CONST_MAP_PTR,
|
|
.arg2_type = ARG_ANYTHING,
|
|
};
|
|
|
|
BPF_CALL_3(bpf_probe_read_str, void *, dst, u32, size,
|
|
const void *, unsafe_ptr)
|
|
{
|
|
int ret;
|
|
|
|
/*
|
|
* The strncpy_from_unsafe() call will likely not fill the entire
|
|
* buffer, but that's okay in this circumstance as we're probing
|
|
* arbitrary memory anyway similar to bpf_probe_read() and might
|
|
* as well probe the stack. Thus, memory is explicitly cleared
|
|
* only in error case, so that improper users ignoring return
|
|
* code altogether don't copy garbage; otherwise length of string
|
|
* is returned that can be used for bpf_perf_event_output() et al.
|
|
*/
|
|
ret = strncpy_from_unsafe(dst, unsafe_ptr, size);
|
|
if (unlikely(ret < 0))
|
|
memset(dst, 0, size);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static const struct bpf_func_proto bpf_probe_read_str_proto = {
|
|
.func = bpf_probe_read_str,
|
|
.gpl_only = true,
|
|
.ret_type = RET_INTEGER,
|
|
.arg1_type = ARG_PTR_TO_UNINIT_MEM,
|
|
.arg2_type = ARG_CONST_SIZE_OR_ZERO,
|
|
.arg3_type = ARG_ANYTHING,
|
|
};
|
|
|
|
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_get_numa_node_id:
|
|
return &bpf_get_numa_node_id_proto;
|
|
case BPF_FUNC_perf_event_read:
|
|
return &bpf_perf_event_read_proto;
|
|
case BPF_FUNC_probe_write_user:
|
|
return bpf_get_probe_write_proto();
|
|
case BPF_FUNC_current_task_under_cgroup:
|
|
return &bpf_current_task_under_cgroup_proto;
|
|
case BPF_FUNC_get_prandom_u32:
|
|
return &bpf_get_prandom_u32_proto;
|
|
case BPF_FUNC_probe_read_str:
|
|
return &bpf_probe_read_str_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;
|
|
case BPF_FUNC_perf_event_read_value:
|
|
return &bpf_perf_event_read_value_proto;
|
|
#ifdef CONFIG_BPF_KPROBE_OVERRIDE
|
|
case BPF_FUNC_override_return:
|
|
return &bpf_override_return_proto;
|
|
#endif
|
|
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,
|
|
struct bpf_insn_access_aux *info)
|
|
{
|
|
if (off < 0 || off >= sizeof(struct pt_regs))
|
|
return false;
|
|
if (type != BPF_READ)
|
|
return false;
|
|
if (off % size != 0)
|
|
return false;
|
|
/*
|
|
* Assertion for 32 bit to make sure last 8 byte access
|
|
* (BPF_DW) to the last 4 byte member is disallowed.
|
|
*/
|
|
if (off + size > sizeof(struct pt_regs))
|
|
return false;
|
|
|
|
return true;
|
|
}
|
|
|
|
const struct bpf_verifier_ops kprobe_verifier_ops = {
|
|
.get_func_proto = kprobe_prog_func_proto,
|
|
.is_valid_access = kprobe_prog_is_valid_access,
|
|
};
|
|
|
|
const struct bpf_prog_ops kprobe_prog_ops = {
|
|
};
|
|
|
|
BPF_CALL_5(bpf_perf_event_output_tp, void *, tp_buff, struct bpf_map *, map,
|
|
u64, flags, void *, data, u64, size)
|
|
{
|
|
struct pt_regs *regs = *(struct pt_regs **)tp_buff;
|
|
|
|
/*
|
|
* 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 inline.
|
|
*/
|
|
return ____bpf_perf_event_output(regs, map, flags, data, 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_MEM,
|
|
.arg5_type = ARG_CONST_SIZE_OR_ZERO,
|
|
};
|
|
|
|
BPF_CALL_3(bpf_get_stackid_tp, void *, tp_buff, struct bpf_map *, map,
|
|
u64, flags)
|
|
{
|
|
struct pt_regs *regs = *(struct pt_regs **)tp_buff;
|
|
|
|
/*
|
|
* Same comment as in bpf_perf_event_output_tp(), only that this time
|
|
* the other helper's function body cannot be inlined due to being
|
|
* external, thus we need to call raw helper function.
|
|
*/
|
|
return bpf_get_stackid((unsigned long) regs, (unsigned long) map,
|
|
flags, 0, 0);
|
|
}
|
|
|
|
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,
|
|
struct bpf_insn_access_aux *info)
|
|
{
|
|
if (off < sizeof(void *) || off >= PERF_MAX_TRACE_SIZE)
|
|
return false;
|
|
if (type != BPF_READ)
|
|
return false;
|
|
if (off % size != 0)
|
|
return false;
|
|
|
|
BUILD_BUG_ON(PERF_MAX_TRACE_SIZE % sizeof(__u64));
|
|
return true;
|
|
}
|
|
|
|
const struct bpf_verifier_ops tracepoint_verifier_ops = {
|
|
.get_func_proto = tp_prog_func_proto,
|
|
.is_valid_access = tp_prog_is_valid_access,
|
|
};
|
|
|
|
const struct bpf_prog_ops tracepoint_prog_ops = {
|
|
};
|
|
|
|
BPF_CALL_3(bpf_perf_prog_read_value, struct bpf_perf_event_data_kern *, ctx,
|
|
struct bpf_perf_event_value *, buf, u32, size)
|
|
{
|
|
int err = -EINVAL;
|
|
|
|
if (unlikely(size != sizeof(struct bpf_perf_event_value)))
|
|
goto clear;
|
|
err = perf_event_read_local(ctx->event, &buf->counter, &buf->enabled,
|
|
&buf->running);
|
|
if (unlikely(err))
|
|
goto clear;
|
|
return 0;
|
|
clear:
|
|
memset(buf, 0, size);
|
|
return err;
|
|
}
|
|
|
|
static const struct bpf_func_proto bpf_perf_prog_read_value_proto = {
|
|
.func = bpf_perf_prog_read_value,
|
|
.gpl_only = true,
|
|
.ret_type = RET_INTEGER,
|
|
.arg1_type = ARG_PTR_TO_CTX,
|
|
.arg2_type = ARG_PTR_TO_UNINIT_MEM,
|
|
.arg3_type = ARG_CONST_SIZE,
|
|
};
|
|
|
|
static const struct bpf_func_proto *pe_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;
|
|
case BPF_FUNC_perf_prog_read_value:
|
|
return &bpf_perf_prog_read_value_proto;
|
|
default:
|
|
return tracing_func_proto(func_id);
|
|
}
|
|
}
|
|
|
|
static bool pe_prog_is_valid_access(int off, int size, enum bpf_access_type type,
|
|
struct bpf_insn_access_aux *info)
|
|
{
|
|
const int size_sp = FIELD_SIZEOF(struct bpf_perf_event_data,
|
|
sample_period);
|
|
|
|
if (off < 0 || off >= sizeof(struct bpf_perf_event_data))
|
|
return false;
|
|
if (type != BPF_READ)
|
|
return false;
|
|
if (off % size != 0)
|
|
return false;
|
|
|
|
switch (off) {
|
|
case bpf_ctx_range(struct bpf_perf_event_data, sample_period):
|
|
bpf_ctx_record_field_size(info, size_sp);
|
|
if (!bpf_ctx_narrow_access_ok(off, size, size_sp))
|
|
return false;
|
|
break;
|
|
default:
|
|
if (size != sizeof(long))
|
|
return false;
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
static u32 pe_prog_convert_ctx_access(enum bpf_access_type type,
|
|
const struct bpf_insn *si,
|
|
struct bpf_insn *insn_buf,
|
|
struct bpf_prog *prog, u32 *target_size)
|
|
{
|
|
struct bpf_insn *insn = insn_buf;
|
|
|
|
switch (si->off) {
|
|
case offsetof(struct bpf_perf_event_data, sample_period):
|
|
*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_perf_event_data_kern,
|
|
data), si->dst_reg, si->src_reg,
|
|
offsetof(struct bpf_perf_event_data_kern, data));
|
|
*insn++ = BPF_LDX_MEM(BPF_DW, si->dst_reg, si->dst_reg,
|
|
bpf_target_off(struct perf_sample_data, period, 8,
|
|
target_size));
|
|
break;
|
|
default:
|
|
*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct bpf_perf_event_data_kern,
|
|
regs), si->dst_reg, si->src_reg,
|
|
offsetof(struct bpf_perf_event_data_kern, regs));
|
|
*insn++ = BPF_LDX_MEM(BPF_SIZEOF(long), si->dst_reg, si->dst_reg,
|
|
si->off);
|
|
break;
|
|
}
|
|
|
|
return insn - insn_buf;
|
|
}
|
|
|
|
const struct bpf_verifier_ops perf_event_verifier_ops = {
|
|
.get_func_proto = pe_prog_func_proto,
|
|
.is_valid_access = pe_prog_is_valid_access,
|
|
.convert_ctx_access = pe_prog_convert_ctx_access,
|
|
};
|
|
|
|
const struct bpf_prog_ops perf_event_prog_ops = {
|
|
};
|
|
|
|
static DEFINE_MUTEX(bpf_event_mutex);
|
|
|
|
#define BPF_TRACE_MAX_PROGS 64
|
|
|
|
int perf_event_attach_bpf_prog(struct perf_event *event,
|
|
struct bpf_prog *prog)
|
|
{
|
|
struct bpf_prog_array __rcu *old_array;
|
|
struct bpf_prog_array *new_array;
|
|
int ret = -EEXIST;
|
|
|
|
/*
|
|
* Kprobe override only works if they are on the function entry,
|
|
* and only if they are on the opt-in list.
|
|
*/
|
|
if (prog->kprobe_override &&
|
|
(!trace_kprobe_on_func_entry(event->tp_event) ||
|
|
!trace_kprobe_error_injectable(event->tp_event)))
|
|
return -EINVAL;
|
|
|
|
mutex_lock(&bpf_event_mutex);
|
|
|
|
if (event->prog)
|
|
goto unlock;
|
|
|
|
old_array = event->tp_event->prog_array;
|
|
if (old_array &&
|
|
bpf_prog_array_length(old_array) >= BPF_TRACE_MAX_PROGS) {
|
|
ret = -E2BIG;
|
|
goto unlock;
|
|
}
|
|
|
|
ret = bpf_prog_array_copy(old_array, NULL, prog, &new_array);
|
|
if (ret < 0)
|
|
goto unlock;
|
|
|
|
/* set the new array to event->tp_event and set event->prog */
|
|
event->prog = prog;
|
|
rcu_assign_pointer(event->tp_event->prog_array, new_array);
|
|
bpf_prog_array_free(old_array);
|
|
|
|
unlock:
|
|
mutex_unlock(&bpf_event_mutex);
|
|
return ret;
|
|
}
|
|
|
|
void perf_event_detach_bpf_prog(struct perf_event *event)
|
|
{
|
|
struct bpf_prog_array __rcu *old_array;
|
|
struct bpf_prog_array *new_array;
|
|
int ret;
|
|
|
|
mutex_lock(&bpf_event_mutex);
|
|
|
|
if (!event->prog)
|
|
goto unlock;
|
|
|
|
old_array = event->tp_event->prog_array;
|
|
ret = bpf_prog_array_copy(old_array, event->prog, NULL, &new_array);
|
|
if (ret < 0) {
|
|
bpf_prog_array_delete_safe(old_array, event->prog);
|
|
} else {
|
|
rcu_assign_pointer(event->tp_event->prog_array, new_array);
|
|
bpf_prog_array_free(old_array);
|
|
}
|
|
|
|
bpf_prog_put(event->prog);
|
|
event->prog = NULL;
|
|
|
|
unlock:
|
|
mutex_unlock(&bpf_event_mutex);
|
|
}
|
|
|
|
int perf_event_query_prog_array(struct perf_event *event, void __user *info)
|
|
{
|
|
struct perf_event_query_bpf __user *uquery = info;
|
|
struct perf_event_query_bpf query = {};
|
|
int ret;
|
|
|
|
if (!capable(CAP_SYS_ADMIN))
|
|
return -EPERM;
|
|
if (event->attr.type != PERF_TYPE_TRACEPOINT)
|
|
return -EINVAL;
|
|
if (copy_from_user(&query, uquery, sizeof(query)))
|
|
return -EFAULT;
|
|
if (query.ids_len > BPF_TRACE_MAX_PROGS)
|
|
return -E2BIG;
|
|
|
|
mutex_lock(&bpf_event_mutex);
|
|
ret = bpf_prog_array_copy_info(event->tp_event->prog_array,
|
|
uquery->ids,
|
|
query.ids_len,
|
|
&uquery->prog_cnt);
|
|
mutex_unlock(&bpf_event_mutex);
|
|
|
|
return ret;
|
|
}
|