// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Linux Socket Filter - Kernel level socket filtering
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*
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* Based on the design of the Berkeley Packet Filter. The new
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* internal format has been designed by PLUMgrid:
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*
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* Copyright (c) 2011 - 2014 PLUMgrid, http://plumgrid.com
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*
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* Authors:
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*
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* Jay Schulist <jschlst@samba.org>
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* Alexei Starovoitov <ast@plumgrid.com>
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* Daniel Borkmann <dborkman@redhat.com>
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*
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* Andi Kleen - Fix a few bad bugs and races.
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* Kris Katterjohn - Added many additional checks in bpf_check_classic()
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*/
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#include <uapi/linux/btf.h>
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#include <linux/filter.h>
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#include <linux/skbuff.h>
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#include <linux/vmalloc.h>
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#include <linux/random.h>
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#include <linux/moduleloader.h>
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#include <linux/bpf.h>
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#include <linux/btf.h>
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#include <linux/objtool.h>
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#include <linux/rbtree_latch.h>
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#include <linux/kallsyms.h>
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#include <linux/rcupdate.h>
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#include <linux/perf_event.h>
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#include <linux/extable.h>
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#include <linux/log2.h>
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#include <asm/barrier.h>
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#include <asm/unaligned.h>
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#include <trace/hooks/memory.h>
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/* Registers */
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#define BPF_R0 regs[BPF_REG_0]
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#define BPF_R1 regs[BPF_REG_1]
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#define BPF_R2 regs[BPF_REG_2]
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#define BPF_R3 regs[BPF_REG_3]
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#define BPF_R4 regs[BPF_REG_4]
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#define BPF_R5 regs[BPF_REG_5]
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#define BPF_R6 regs[BPF_REG_6]
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#define BPF_R7 regs[BPF_REG_7]
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#define BPF_R8 regs[BPF_REG_8]
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#define BPF_R9 regs[BPF_REG_9]
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#define BPF_R10 regs[BPF_REG_10]
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/* Named registers */
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#define DST regs[insn->dst_reg]
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#define SRC regs[insn->src_reg]
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#define FP regs[BPF_REG_FP]
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#define AX regs[BPF_REG_AX]
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#define ARG1 regs[BPF_REG_ARG1]
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#define CTX regs[BPF_REG_CTX]
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#define IMM insn->imm
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/* No hurry in this branch
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*
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* Exported for the bpf jit load helper.
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*/
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void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb, int k, unsigned int size)
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{
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u8 *ptr = NULL;
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if (k >= SKF_NET_OFF) {
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ptr = skb_network_header(skb) + k - SKF_NET_OFF;
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} else if (k >= SKF_LL_OFF) {
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if (unlikely(!skb_mac_header_was_set(skb)))
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return NULL;
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ptr = skb_mac_header(skb) + k - SKF_LL_OFF;
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}
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if (ptr >= skb->head && ptr + size <= skb_tail_pointer(skb))
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return ptr;
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return NULL;
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}
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struct bpf_prog *bpf_prog_alloc_no_stats(unsigned int size, gfp_t gfp_extra_flags)
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{
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gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags;
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struct bpf_prog_aux *aux;
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struct bpf_prog *fp;
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size = round_up(size, PAGE_SIZE);
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fp = __vmalloc(size, gfp_flags);
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if (fp == NULL)
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return NULL;
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aux = kzalloc(sizeof(*aux), GFP_KERNEL | gfp_extra_flags);
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if (aux == NULL) {
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vfree(fp);
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return NULL;
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}
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fp->pages = size / PAGE_SIZE;
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fp->aux = aux;
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fp->aux->prog = fp;
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fp->jit_requested = ebpf_jit_enabled();
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INIT_LIST_HEAD_RCU(&fp->aux->ksym.lnode);
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mutex_init(&fp->aux->used_maps_mutex);
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mutex_init(&fp->aux->dst_mutex);
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return fp;
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}
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struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags)
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{
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gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags;
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struct bpf_prog *prog;
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int cpu;
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prog = bpf_prog_alloc_no_stats(size, gfp_extra_flags);
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if (!prog)
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return NULL;
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prog->aux->stats = alloc_percpu_gfp(struct bpf_prog_stats, gfp_flags);
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if (!prog->aux->stats) {
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kfree(prog->aux);
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vfree(prog);
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return NULL;
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}
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for_each_possible_cpu(cpu) {
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struct bpf_prog_stats *pstats;
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pstats = per_cpu_ptr(prog->aux->stats, cpu);
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u64_stats_init(&pstats->syncp);
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}
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return prog;
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}
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EXPORT_SYMBOL_GPL(bpf_prog_alloc);
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int bpf_prog_alloc_jited_linfo(struct bpf_prog *prog)
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{
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if (!prog->aux->nr_linfo || !prog->jit_requested)
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return 0;
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prog->aux->jited_linfo = kcalloc(prog->aux->nr_linfo,
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sizeof(*prog->aux->jited_linfo),
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GFP_KERNEL | __GFP_NOWARN);
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if (!prog->aux->jited_linfo)
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return -ENOMEM;
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return 0;
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}
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void bpf_prog_free_jited_linfo(struct bpf_prog *prog)
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{
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kfree(prog->aux->jited_linfo);
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prog->aux->jited_linfo = NULL;
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}
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void bpf_prog_free_unused_jited_linfo(struct bpf_prog *prog)
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{
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if (prog->aux->jited_linfo && !prog->aux->jited_linfo[0])
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bpf_prog_free_jited_linfo(prog);
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}
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/* The jit engine is responsible to provide an array
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* for insn_off to the jited_off mapping (insn_to_jit_off).
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*
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* The idx to this array is the insn_off. Hence, the insn_off
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* here is relative to the prog itself instead of the main prog.
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* This array has one entry for each xlated bpf insn.
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*
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* jited_off is the byte off to the last byte of the jited insn.
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*
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* Hence, with
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* insn_start:
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* The first bpf insn off of the prog. The insn off
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* here is relative to the main prog.
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* e.g. if prog is a subprog, insn_start > 0
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* linfo_idx:
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* The prog's idx to prog->aux->linfo and jited_linfo
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*
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* jited_linfo[linfo_idx] = prog->bpf_func
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*
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* For i > linfo_idx,
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*
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* jited_linfo[i] = prog->bpf_func +
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* insn_to_jit_off[linfo[i].insn_off - insn_start - 1]
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*/
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void bpf_prog_fill_jited_linfo(struct bpf_prog *prog,
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const u32 *insn_to_jit_off)
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{
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u32 linfo_idx, insn_start, insn_end, nr_linfo, i;
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const struct bpf_line_info *linfo;
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void **jited_linfo;
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if (!prog->aux->jited_linfo)
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/* Userspace did not provide linfo */
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return;
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linfo_idx = prog->aux->linfo_idx;
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linfo = &prog->aux->linfo[linfo_idx];
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insn_start = linfo[0].insn_off;
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insn_end = insn_start + prog->len;
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jited_linfo = &prog->aux->jited_linfo[linfo_idx];
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jited_linfo[0] = prog->bpf_func;
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nr_linfo = prog->aux->nr_linfo - linfo_idx;
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for (i = 1; i < nr_linfo && linfo[i].insn_off < insn_end; i++)
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/* The verifier ensures that linfo[i].insn_off is
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* strictly increasing
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*/
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jited_linfo[i] = prog->bpf_func +
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insn_to_jit_off[linfo[i].insn_off - insn_start - 1];
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}
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void bpf_prog_free_linfo(struct bpf_prog *prog)
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{
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bpf_prog_free_jited_linfo(prog);
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kvfree(prog->aux->linfo);
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}
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struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size,
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gfp_t gfp_extra_flags)
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{
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gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags;
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struct bpf_prog *fp;
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u32 pages, delta;
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int ret;
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size = round_up(size, PAGE_SIZE);
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pages = size / PAGE_SIZE;
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if (pages <= fp_old->pages)
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return fp_old;
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delta = pages - fp_old->pages;
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ret = __bpf_prog_charge(fp_old->aux->user, delta);
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if (ret)
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return NULL;
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fp = __vmalloc(size, gfp_flags);
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if (fp == NULL) {
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__bpf_prog_uncharge(fp_old->aux->user, delta);
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} else {
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memcpy(fp, fp_old, fp_old->pages * PAGE_SIZE);
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fp->pages = pages;
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fp->aux->prog = fp;
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/* We keep fp->aux from fp_old around in the new
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* reallocated structure.
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*/
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fp_old->aux = NULL;
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__bpf_prog_free(fp_old);
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}
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return fp;
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}
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void __bpf_prog_free(struct bpf_prog *fp)
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{
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if (fp->aux) {
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mutex_destroy(&fp->aux->used_maps_mutex);
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mutex_destroy(&fp->aux->dst_mutex);
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free_percpu(fp->aux->stats);
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kfree(fp->aux->poke_tab);
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kfree(fp->aux);
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}
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vfree(fp);
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}
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int bpf_prog_calc_tag(struct bpf_prog *fp)
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{
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const u32 bits_offset = SHA1_BLOCK_SIZE - sizeof(__be64);
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u32 raw_size = bpf_prog_tag_scratch_size(fp);
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u32 digest[SHA1_DIGEST_WORDS];
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u32 ws[SHA1_WORKSPACE_WORDS];
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u32 i, bsize, psize, blocks;
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struct bpf_insn *dst;
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bool was_ld_map;
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u8 *raw, *todo;
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__be32 *result;
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__be64 *bits;
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raw = vmalloc(raw_size);
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if (!raw)
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return -ENOMEM;
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sha1_init(digest);
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memset(ws, 0, sizeof(ws));
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/* We need to take out the map fd for the digest calculation
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* since they are unstable from user space side.
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*/
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dst = (void *)raw;
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for (i = 0, was_ld_map = false; i < fp->len; i++) {
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dst[i] = fp->insnsi[i];
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if (!was_ld_map &&
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dst[i].code == (BPF_LD | BPF_IMM | BPF_DW) &&
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(dst[i].src_reg == BPF_PSEUDO_MAP_FD ||
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dst[i].src_reg == BPF_PSEUDO_MAP_VALUE)) {
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was_ld_map = true;
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dst[i].imm = 0;
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} else if (was_ld_map &&
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dst[i].code == 0 &&
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dst[i].dst_reg == 0 &&
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dst[i].src_reg == 0 &&
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dst[i].off == 0) {
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was_ld_map = false;
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dst[i].imm = 0;
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} else {
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was_ld_map = false;
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}
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}
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psize = bpf_prog_insn_size(fp);
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memset(&raw[psize], 0, raw_size - psize);
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raw[psize++] = 0x80;
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bsize = round_up(psize, SHA1_BLOCK_SIZE);
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blocks = bsize / SHA1_BLOCK_SIZE;
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todo = raw;
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if (bsize - psize >= sizeof(__be64)) {
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bits = (__be64 *)(todo + bsize - sizeof(__be64));
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} else {
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bits = (__be64 *)(todo + bsize + bits_offset);
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blocks++;
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}
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*bits = cpu_to_be64((psize - 1) << 3);
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while (blocks--) {
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sha1_transform(digest, todo, ws);
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todo += SHA1_BLOCK_SIZE;
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}
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result = (__force __be32 *)digest;
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for (i = 0; i < SHA1_DIGEST_WORDS; i++)
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result[i] = cpu_to_be32(digest[i]);
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memcpy(fp->tag, result, sizeof(fp->tag));
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vfree(raw);
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return 0;
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}
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static int bpf_adj_delta_to_imm(struct bpf_insn *insn, u32 pos, s32 end_old,
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s32 end_new, s32 curr, const bool probe_pass)
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{
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const s64 imm_min = S32_MIN, imm_max = S32_MAX;
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s32 delta = end_new - end_old;
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s64 imm = insn->imm;
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if (curr < pos && curr + imm + 1 >= end_old)
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imm += delta;
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else if (curr >= end_new && curr + imm + 1 < end_new)
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imm -= delta;
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if (imm < imm_min || imm > imm_max)
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return -ERANGE;
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if (!probe_pass)
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insn->imm = imm;
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return 0;
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}
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static int bpf_adj_delta_to_off(struct bpf_insn *insn, u32 pos, s32 end_old,
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s32 end_new, s32 curr, const bool probe_pass)
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{
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const s32 off_min = S16_MIN, off_max = S16_MAX;
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s32 delta = end_new - end_old;
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s32 off = insn->off;
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if (curr < pos && curr + off + 1 >= end_old)
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off += delta;
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else if (curr >= end_new && curr + off + 1 < end_new)
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off -= delta;
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if (off < off_min || off > off_max)
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return -ERANGE;
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if (!probe_pass)
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insn->off = off;
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return 0;
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}
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static int bpf_adj_branches(struct bpf_prog *prog, u32 pos, s32 end_old,
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s32 end_new, const bool probe_pass)
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{
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u32 i, insn_cnt = prog->len + (probe_pass ? end_new - end_old : 0);
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struct bpf_insn *insn = prog->insnsi;
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int ret = 0;
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for (i = 0; i < insn_cnt; i++, insn++) {
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u8 code;
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/* In the probing pass we still operate on the original,
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* unpatched image in order to check overflows before we
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* do any other adjustments. Therefore skip the patchlet.
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*/
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if (probe_pass && i == pos) {
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i = end_new;
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insn = prog->insnsi + end_old;
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}
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code = insn->code;
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if ((BPF_CLASS(code) != BPF_JMP &&
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BPF_CLASS(code) != BPF_JMP32) ||
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BPF_OP(code) == BPF_EXIT)
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continue;
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/* Adjust offset of jmps if we cross patch boundaries. */
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if (BPF_OP(code) == BPF_CALL) {
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if (insn->src_reg != BPF_PSEUDO_CALL)
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continue;
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ret = bpf_adj_delta_to_imm(insn, pos, end_old,
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end_new, i, probe_pass);
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} else {
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ret = bpf_adj_delta_to_off(insn, pos, end_old,
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end_new, i, probe_pass);
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}
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if (ret)
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break;
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}
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return ret;
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}
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static void bpf_adj_linfo(struct bpf_prog *prog, u32 off, u32 delta)
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{
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struct bpf_line_info *linfo;
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u32 i, nr_linfo;
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nr_linfo = prog->aux->nr_linfo;
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if (!nr_linfo || !delta)
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return;
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linfo = prog->aux->linfo;
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for (i = 0; i < nr_linfo; i++)
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if (off < linfo[i].insn_off)
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break;
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/* Push all off < linfo[i].insn_off by delta */
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for (; i < nr_linfo; i++)
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linfo[i].insn_off += delta;
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}
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struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off,
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const struct bpf_insn *patch, u32 len)
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{
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u32 insn_adj_cnt, insn_rest, insn_delta = len - 1;
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const u32 cnt_max = S16_MAX;
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struct bpf_prog *prog_adj;
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int err;
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/* Since our patchlet doesn't expand the image, we're done. */
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if (insn_delta == 0) {
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memcpy(prog->insnsi + off, patch, sizeof(*patch));
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return prog;
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}
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insn_adj_cnt = prog->len + insn_delta;
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/* Reject anything that would potentially let the insn->off
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* target overflow when we have excessive program expansions.
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* We need to probe here before we do any reallocation where
|
* we afterwards may not fail anymore.
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*/
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if (insn_adj_cnt > cnt_max &&
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(err = bpf_adj_branches(prog, off, off + 1, off + len, true)))
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return ERR_PTR(err);
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/* Several new instructions need to be inserted. Make room
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* for them. Likely, there's no need for a new allocation as
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* last page could have large enough tailroom.
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*/
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prog_adj = bpf_prog_realloc(prog, bpf_prog_size(insn_adj_cnt),
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GFP_USER);
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if (!prog_adj)
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return ERR_PTR(-ENOMEM);
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prog_adj->len = insn_adj_cnt;
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/* Patching happens in 3 steps:
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*
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* 1) Move over tail of insnsi from next instruction onwards,
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* so we can patch the single target insn with one or more
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* new ones (patching is always from 1 to n insns, n > 0).
|
* 2) Inject new instructions at the target location.
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* 3) Adjust branch offsets if necessary.
|
*/
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insn_rest = insn_adj_cnt - off - len;
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memmove(prog_adj->insnsi + off + len, prog_adj->insnsi + off + 1,
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sizeof(*patch) * insn_rest);
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memcpy(prog_adj->insnsi + off, patch, sizeof(*patch) * len);
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/* We are guaranteed to not fail at this point, otherwise
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* the ship has sailed to reverse to the original state. An
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* overflow cannot happen at this point.
|
*/
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BUG_ON(bpf_adj_branches(prog_adj, off, off + 1, off + len, false));
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bpf_adj_linfo(prog_adj, off, insn_delta);
|
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return prog_adj;
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}
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int bpf_remove_insns(struct bpf_prog *prog, u32 off, u32 cnt)
|
{
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/* Branch offsets can't overflow when program is shrinking, no need
|
* to call bpf_adj_branches(..., true) here
|
*/
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memmove(prog->insnsi + off, prog->insnsi + off + cnt,
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sizeof(struct bpf_insn) * (prog->len - off - cnt));
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prog->len -= cnt;
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return WARN_ON_ONCE(bpf_adj_branches(prog, off, off + cnt, off, false));
|
}
|
|
static void bpf_prog_kallsyms_del_subprogs(struct bpf_prog *fp)
|
{
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int i;
|
|
for (i = 0; i < fp->aux->func_cnt; i++)
|
bpf_prog_kallsyms_del(fp->aux->func[i]);
|
}
|
|
void bpf_prog_kallsyms_del_all(struct bpf_prog *fp)
|
{
|
bpf_prog_kallsyms_del_subprogs(fp);
|
bpf_prog_kallsyms_del(fp);
|
}
|
|
#ifdef CONFIG_BPF_JIT
|
/* All BPF JIT sysctl knobs here. */
|
int bpf_jit_enable __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_DEFAULT_ON);
|
int bpf_jit_kallsyms __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_DEFAULT_ON);
|
int bpf_jit_harden __read_mostly;
|
long bpf_jit_limit __read_mostly;
|
long bpf_jit_limit_max __read_mostly;
|
|
static void
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bpf_prog_ksym_set_addr(struct bpf_prog *prog)
|
{
|
const struct bpf_binary_header *hdr = bpf_jit_binary_hdr(prog);
|
unsigned long addr = (unsigned long)hdr;
|
|
WARN_ON_ONCE(!bpf_prog_ebpf_jited(prog));
|
|
prog->aux->ksym.start = (unsigned long) prog->bpf_func;
|
prog->aux->ksym.end = addr + hdr->pages * PAGE_SIZE;
|
}
|
|
static void
|
bpf_prog_ksym_set_name(struct bpf_prog *prog)
|
{
|
char *sym = prog->aux->ksym.name;
|
const char *end = sym + KSYM_NAME_LEN;
|
const struct btf_type *type;
|
const char *func_name;
|
|
BUILD_BUG_ON(sizeof("bpf_prog_") +
|
sizeof(prog->tag) * 2 +
|
/* name has been null terminated.
|
* We should need +1 for the '_' preceding
|
* the name. However, the null character
|
* is double counted between the name and the
|
* sizeof("bpf_prog_") above, so we omit
|
* the +1 here.
|
*/
|
sizeof(prog->aux->name) > KSYM_NAME_LEN);
|
|
sym += snprintf(sym, KSYM_NAME_LEN, "bpf_prog_");
|
sym = bin2hex(sym, prog->tag, sizeof(prog->tag));
|
|
/* prog->aux->name will be ignored if full btf name is available */
|
if (prog->aux->func_info_cnt) {
|
type = btf_type_by_id(prog->aux->btf,
|
prog->aux->func_info[prog->aux->func_idx].type_id);
|
func_name = btf_name_by_offset(prog->aux->btf, type->name_off);
|
snprintf(sym, (size_t)(end - sym), "_%s", func_name);
|
return;
|
}
|
|
if (prog->aux->name[0])
|
snprintf(sym, (size_t)(end - sym), "_%s", prog->aux->name);
|
else
|
*sym = 0;
|
}
|
|
static unsigned long bpf_get_ksym_start(struct latch_tree_node *n)
|
{
|
return container_of(n, struct bpf_ksym, tnode)->start;
|
}
|
|
static __always_inline bool bpf_tree_less(struct latch_tree_node *a,
|
struct latch_tree_node *b)
|
{
|
return bpf_get_ksym_start(a) < bpf_get_ksym_start(b);
|
}
|
|
static __always_inline int bpf_tree_comp(void *key, struct latch_tree_node *n)
|
{
|
unsigned long val = (unsigned long)key;
|
const struct bpf_ksym *ksym;
|
|
ksym = container_of(n, struct bpf_ksym, tnode);
|
|
if (val < ksym->start)
|
return -1;
|
if (val >= ksym->end)
|
return 1;
|
|
return 0;
|
}
|
|
static const struct latch_tree_ops bpf_tree_ops = {
|
.less = bpf_tree_less,
|
.comp = bpf_tree_comp,
|
};
|
|
static DEFINE_SPINLOCK(bpf_lock);
|
static LIST_HEAD(bpf_kallsyms);
|
static struct latch_tree_root bpf_tree __cacheline_aligned;
|
|
void bpf_ksym_add(struct bpf_ksym *ksym)
|
{
|
spin_lock_bh(&bpf_lock);
|
WARN_ON_ONCE(!list_empty(&ksym->lnode));
|
list_add_tail_rcu(&ksym->lnode, &bpf_kallsyms);
|
latch_tree_insert(&ksym->tnode, &bpf_tree, &bpf_tree_ops);
|
spin_unlock_bh(&bpf_lock);
|
}
|
|
static void __bpf_ksym_del(struct bpf_ksym *ksym)
|
{
|
if (list_empty(&ksym->lnode))
|
return;
|
|
latch_tree_erase(&ksym->tnode, &bpf_tree, &bpf_tree_ops);
|
list_del_rcu(&ksym->lnode);
|
}
|
|
void bpf_ksym_del(struct bpf_ksym *ksym)
|
{
|
spin_lock_bh(&bpf_lock);
|
__bpf_ksym_del(ksym);
|
spin_unlock_bh(&bpf_lock);
|
}
|
|
static bool bpf_prog_kallsyms_candidate(const struct bpf_prog *fp)
|
{
|
return fp->jited && !bpf_prog_was_classic(fp);
|
}
|
|
static bool bpf_prog_kallsyms_verify_off(const struct bpf_prog *fp)
|
{
|
return list_empty(&fp->aux->ksym.lnode) ||
|
fp->aux->ksym.lnode.prev == LIST_POISON2;
|
}
|
|
void bpf_prog_kallsyms_add(struct bpf_prog *fp)
|
{
|
if (!bpf_prog_kallsyms_candidate(fp) ||
|
!bpf_capable())
|
return;
|
|
bpf_prog_ksym_set_addr(fp);
|
bpf_prog_ksym_set_name(fp);
|
fp->aux->ksym.prog = true;
|
|
bpf_ksym_add(&fp->aux->ksym);
|
}
|
|
void bpf_prog_kallsyms_del(struct bpf_prog *fp)
|
{
|
if (!bpf_prog_kallsyms_candidate(fp))
|
return;
|
|
bpf_ksym_del(&fp->aux->ksym);
|
}
|
|
static struct bpf_ksym *bpf_ksym_find(unsigned long addr)
|
{
|
struct latch_tree_node *n;
|
|
n = latch_tree_find((void *)addr, &bpf_tree, &bpf_tree_ops);
|
return n ? container_of(n, struct bpf_ksym, tnode) : NULL;
|
}
|
|
const char *__bpf_address_lookup(unsigned long addr, unsigned long *size,
|
unsigned long *off, char *sym)
|
{
|
struct bpf_ksym *ksym;
|
char *ret = NULL;
|
|
rcu_read_lock();
|
ksym = bpf_ksym_find(addr);
|
if (ksym) {
|
unsigned long symbol_start = ksym->start;
|
unsigned long symbol_end = ksym->end;
|
|
strncpy(sym, ksym->name, KSYM_NAME_LEN);
|
|
ret = sym;
|
if (size)
|
*size = symbol_end - symbol_start;
|
if (off)
|
*off = addr - symbol_start;
|
}
|
rcu_read_unlock();
|
|
return ret;
|
}
|
|
bool is_bpf_text_address(unsigned long addr)
|
{
|
bool ret;
|
|
rcu_read_lock();
|
ret = bpf_ksym_find(addr) != NULL;
|
rcu_read_unlock();
|
|
return ret;
|
}
|
|
static struct bpf_prog *bpf_prog_ksym_find(unsigned long addr)
|
{
|
struct bpf_ksym *ksym = bpf_ksym_find(addr);
|
|
return ksym && ksym->prog ?
|
container_of(ksym, struct bpf_prog_aux, ksym)->prog :
|
NULL;
|
}
|
|
const struct exception_table_entry *search_bpf_extables(unsigned long addr)
|
{
|
const struct exception_table_entry *e = NULL;
|
struct bpf_prog *prog;
|
|
rcu_read_lock();
|
prog = bpf_prog_ksym_find(addr);
|
if (!prog)
|
goto out;
|
if (!prog->aux->num_exentries)
|
goto out;
|
|
e = search_extable(prog->aux->extable, prog->aux->num_exentries, addr);
|
out:
|
rcu_read_unlock();
|
return e;
|
}
|
|
int bpf_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
|
char *sym)
|
{
|
struct bpf_ksym *ksym;
|
unsigned int it = 0;
|
int ret = -ERANGE;
|
|
if (!bpf_jit_kallsyms_enabled())
|
return ret;
|
|
rcu_read_lock();
|
list_for_each_entry_rcu(ksym, &bpf_kallsyms, lnode) {
|
if (it++ != symnum)
|
continue;
|
|
strncpy(sym, ksym->name, KSYM_NAME_LEN);
|
|
*value = ksym->start;
|
*type = BPF_SYM_ELF_TYPE;
|
|
ret = 0;
|
break;
|
}
|
rcu_read_unlock();
|
|
return ret;
|
}
|
|
int bpf_jit_add_poke_descriptor(struct bpf_prog *prog,
|
struct bpf_jit_poke_descriptor *poke)
|
{
|
struct bpf_jit_poke_descriptor *tab = prog->aux->poke_tab;
|
static const u32 poke_tab_max = 1024;
|
u32 slot = prog->aux->size_poke_tab;
|
u32 size = slot + 1;
|
|
if (size > poke_tab_max)
|
return -ENOSPC;
|
if (poke->tailcall_target || poke->tailcall_target_stable ||
|
poke->tailcall_bypass || poke->adj_off || poke->bypass_addr)
|
return -EINVAL;
|
|
switch (poke->reason) {
|
case BPF_POKE_REASON_TAIL_CALL:
|
if (!poke->tail_call.map)
|
return -EINVAL;
|
break;
|
default:
|
return -EINVAL;
|
}
|
|
tab = krealloc(tab, size * sizeof(*poke), GFP_KERNEL);
|
if (!tab)
|
return -ENOMEM;
|
|
memcpy(&tab[slot], poke, sizeof(*poke));
|
prog->aux->size_poke_tab = size;
|
prog->aux->poke_tab = tab;
|
|
return slot;
|
}
|
|
static atomic_long_t bpf_jit_current;
|
|
/* Can be overridden by an arch's JIT compiler if it has a custom,
|
* dedicated BPF backend memory area, or if neither of the two
|
* below apply.
|
*/
|
u64 __weak bpf_jit_alloc_exec_limit(void)
|
{
|
#if defined(MODULES_VADDR)
|
return MODULES_END - MODULES_VADDR;
|
#else
|
return VMALLOC_END - VMALLOC_START;
|
#endif
|
}
|
|
static int __init bpf_jit_charge_init(void)
|
{
|
/* Only used as heuristic here to derive limit. */
|
bpf_jit_limit_max = bpf_jit_alloc_exec_limit();
|
bpf_jit_limit = min_t(u64, round_up(bpf_jit_limit_max >> 2,
|
PAGE_SIZE), LONG_MAX);
|
return 0;
|
}
|
pure_initcall(bpf_jit_charge_init);
|
|
int bpf_jit_charge_modmem(u32 pages)
|
{
|
if (atomic_long_add_return(pages, &bpf_jit_current) >
|
(bpf_jit_limit >> PAGE_SHIFT)) {
|
if (!bpf_capable()) {
|
atomic_long_sub(pages, &bpf_jit_current);
|
return -EPERM;
|
}
|
}
|
|
return 0;
|
}
|
|
void bpf_jit_uncharge_modmem(u32 pages)
|
{
|
atomic_long_sub(pages, &bpf_jit_current);
|
}
|
|
void *__weak bpf_jit_alloc_exec(unsigned long size)
|
{
|
return module_alloc(size);
|
}
|
|
void __weak bpf_jit_free_exec(void *addr)
|
{
|
module_memfree(addr);
|
}
|
|
struct bpf_binary_header *
|
bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr,
|
unsigned int alignment,
|
bpf_jit_fill_hole_t bpf_fill_ill_insns)
|
{
|
struct bpf_binary_header *hdr;
|
u32 size, hole, start, pages;
|
|
WARN_ON_ONCE(!is_power_of_2(alignment) ||
|
alignment > BPF_IMAGE_ALIGNMENT);
|
|
/* Most of BPF filters are really small, but if some of them
|
* fill a page, allow at least 128 extra bytes to insert a
|
* random section of illegal instructions.
|
*/
|
size = round_up(proglen + sizeof(*hdr) + 128, PAGE_SIZE);
|
pages = size / PAGE_SIZE;
|
|
if (bpf_jit_charge_modmem(pages))
|
return NULL;
|
hdr = bpf_jit_alloc_exec(size);
|
if (!hdr) {
|
bpf_jit_uncharge_modmem(pages);
|
return NULL;
|
}
|
|
/* Fill space with illegal/arch-dep instructions. */
|
bpf_fill_ill_insns(hdr, size);
|
|
hdr->pages = pages;
|
hole = min_t(unsigned int, size - (proglen + sizeof(*hdr)),
|
PAGE_SIZE - sizeof(*hdr));
|
start = (get_random_int() % hole) & ~(alignment - 1);
|
|
/* Leave a random number of instructions before BPF code. */
|
*image_ptr = &hdr->image[start];
|
|
return hdr;
|
}
|
|
void bpf_jit_binary_free(struct bpf_binary_header *hdr)
|
{
|
u32 pages = hdr->pages;
|
|
trace_android_vh_set_memory_rw((unsigned long)hdr, pages);
|
trace_android_vh_set_memory_nx((unsigned long)hdr, pages);
|
bpf_jit_free_exec(hdr);
|
bpf_jit_uncharge_modmem(pages);
|
}
|
|
/* This symbol is only overridden by archs that have different
|
* requirements than the usual eBPF JITs, f.e. when they only
|
* implement cBPF JIT, do not set images read-only, etc.
|
*/
|
void __weak bpf_jit_free(struct bpf_prog *fp)
|
{
|
if (fp->jited) {
|
struct bpf_binary_header *hdr = bpf_jit_binary_hdr(fp);
|
|
bpf_jit_binary_free(hdr);
|
|
WARN_ON_ONCE(!bpf_prog_kallsyms_verify_off(fp));
|
}
|
|
bpf_prog_unlock_free(fp);
|
}
|
|
int bpf_jit_get_func_addr(const struct bpf_prog *prog,
|
const struct bpf_insn *insn, bool extra_pass,
|
u64 *func_addr, bool *func_addr_fixed)
|
{
|
s16 off = insn->off;
|
s32 imm = insn->imm;
|
u8 *addr;
|
|
*func_addr_fixed = insn->src_reg != BPF_PSEUDO_CALL;
|
if (!*func_addr_fixed) {
|
/* Place-holder address till the last pass has collected
|
* all addresses for JITed subprograms in which case we
|
* can pick them up from prog->aux.
|
*/
|
if (!extra_pass)
|
addr = NULL;
|
else if (prog->aux->func &&
|
off >= 0 && off < prog->aux->func_cnt)
|
addr = (u8 *)prog->aux->func[off]->bpf_func;
|
else
|
return -EINVAL;
|
} else {
|
/* Address of a BPF helper call. Since part of the core
|
* kernel, it's always at a fixed location. __bpf_call_base
|
* and the helper with imm relative to it are both in core
|
* kernel.
|
*/
|
addr = (u8 *)__bpf_call_base + imm;
|
}
|
|
*func_addr = (unsigned long)addr;
|
return 0;
|
}
|
|
static int bpf_jit_blind_insn(const struct bpf_insn *from,
|
const struct bpf_insn *aux,
|
struct bpf_insn *to_buff,
|
bool emit_zext)
|
{
|
struct bpf_insn *to = to_buff;
|
u32 imm_rnd = get_random_int();
|
s16 off;
|
|
BUILD_BUG_ON(BPF_REG_AX + 1 != MAX_BPF_JIT_REG);
|
BUILD_BUG_ON(MAX_BPF_REG + 1 != MAX_BPF_JIT_REG);
|
|
/* Constraints on AX register:
|
*
|
* AX register is inaccessible from user space. It is mapped in
|
* all JITs, and used here for constant blinding rewrites. It is
|
* typically "stateless" meaning its contents are only valid within
|
* the executed instruction, but not across several instructions.
|
* There are a few exceptions however which are further detailed
|
* below.
|
*
|
* Constant blinding is only used by JITs, not in the interpreter.
|
* The interpreter uses AX in some occasions as a local temporary
|
* register e.g. in DIV or MOD instructions.
|
*
|
* In restricted circumstances, the verifier can also use the AX
|
* register for rewrites as long as they do not interfere with
|
* the above cases!
|
*/
|
if (from->dst_reg == BPF_REG_AX || from->src_reg == BPF_REG_AX)
|
goto out;
|
|
if (from->imm == 0 &&
|
(from->code == (BPF_ALU | BPF_MOV | BPF_K) ||
|
from->code == (BPF_ALU64 | BPF_MOV | BPF_K))) {
|
*to++ = BPF_ALU64_REG(BPF_XOR, from->dst_reg, from->dst_reg);
|
goto out;
|
}
|
|
switch (from->code) {
|
case BPF_ALU | BPF_ADD | BPF_K:
|
case BPF_ALU | BPF_SUB | BPF_K:
|
case BPF_ALU | BPF_AND | BPF_K:
|
case BPF_ALU | BPF_OR | BPF_K:
|
case BPF_ALU | BPF_XOR | BPF_K:
|
case BPF_ALU | BPF_MUL | BPF_K:
|
case BPF_ALU | BPF_MOV | BPF_K:
|
case BPF_ALU | BPF_DIV | BPF_K:
|
case BPF_ALU | BPF_MOD | BPF_K:
|
*to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
|
*to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
|
*to++ = BPF_ALU32_REG(from->code, from->dst_reg, BPF_REG_AX);
|
break;
|
|
case BPF_ALU64 | BPF_ADD | BPF_K:
|
case BPF_ALU64 | BPF_SUB | BPF_K:
|
case BPF_ALU64 | BPF_AND | BPF_K:
|
case BPF_ALU64 | BPF_OR | BPF_K:
|
case BPF_ALU64 | BPF_XOR | BPF_K:
|
case BPF_ALU64 | BPF_MUL | BPF_K:
|
case BPF_ALU64 | BPF_MOV | BPF_K:
|
case BPF_ALU64 | BPF_DIV | BPF_K:
|
case BPF_ALU64 | BPF_MOD | BPF_K:
|
*to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
|
*to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
|
*to++ = BPF_ALU64_REG(from->code, from->dst_reg, BPF_REG_AX);
|
break;
|
|
case BPF_JMP | BPF_JEQ | BPF_K:
|
case BPF_JMP | BPF_JNE | BPF_K:
|
case BPF_JMP | BPF_JGT | BPF_K:
|
case BPF_JMP | BPF_JLT | BPF_K:
|
case BPF_JMP | BPF_JGE | BPF_K:
|
case BPF_JMP | BPF_JLE | BPF_K:
|
case BPF_JMP | BPF_JSGT | BPF_K:
|
case BPF_JMP | BPF_JSLT | BPF_K:
|
case BPF_JMP | BPF_JSGE | BPF_K:
|
case BPF_JMP | BPF_JSLE | BPF_K:
|
case BPF_JMP | BPF_JSET | BPF_K:
|
/* Accommodate for extra offset in case of a backjump. */
|
off = from->off;
|
if (off < 0)
|
off -= 2;
|
*to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
|
*to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
|
*to++ = BPF_JMP_REG(from->code, from->dst_reg, BPF_REG_AX, off);
|
break;
|
|
case BPF_JMP32 | BPF_JEQ | BPF_K:
|
case BPF_JMP32 | BPF_JNE | BPF_K:
|
case BPF_JMP32 | BPF_JGT | BPF_K:
|
case BPF_JMP32 | BPF_JLT | BPF_K:
|
case BPF_JMP32 | BPF_JGE | BPF_K:
|
case BPF_JMP32 | BPF_JLE | BPF_K:
|
case BPF_JMP32 | BPF_JSGT | BPF_K:
|
case BPF_JMP32 | BPF_JSLT | BPF_K:
|
case BPF_JMP32 | BPF_JSGE | BPF_K:
|
case BPF_JMP32 | BPF_JSLE | BPF_K:
|
case BPF_JMP32 | BPF_JSET | BPF_K:
|
/* Accommodate for extra offset in case of a backjump. */
|
off = from->off;
|
if (off < 0)
|
off -= 2;
|
*to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
|
*to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
|
*to++ = BPF_JMP32_REG(from->code, from->dst_reg, BPF_REG_AX,
|
off);
|
break;
|
|
case BPF_LD | BPF_IMM | BPF_DW:
|
*to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[1].imm);
|
*to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
|
*to++ = BPF_ALU64_IMM(BPF_LSH, BPF_REG_AX, 32);
|
*to++ = BPF_ALU64_REG(BPF_MOV, aux[0].dst_reg, BPF_REG_AX);
|
break;
|
case 0: /* Part 2 of BPF_LD | BPF_IMM | BPF_DW. */
|
*to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[0].imm);
|
*to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
|
if (emit_zext)
|
*to++ = BPF_ZEXT_REG(BPF_REG_AX);
|
*to++ = BPF_ALU64_REG(BPF_OR, aux[0].dst_reg, BPF_REG_AX);
|
break;
|
|
case BPF_ST | BPF_MEM | BPF_DW:
|
case BPF_ST | BPF_MEM | BPF_W:
|
case BPF_ST | BPF_MEM | BPF_H:
|
case BPF_ST | BPF_MEM | BPF_B:
|
*to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
|
*to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
|
*to++ = BPF_STX_MEM(from->code, from->dst_reg, BPF_REG_AX, from->off);
|
break;
|
}
|
out:
|
return to - to_buff;
|
}
|
|
static struct bpf_prog *bpf_prog_clone_create(struct bpf_prog *fp_other,
|
gfp_t gfp_extra_flags)
|
{
|
gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags;
|
struct bpf_prog *fp;
|
|
fp = __vmalloc(fp_other->pages * PAGE_SIZE, gfp_flags);
|
if (fp != NULL) {
|
/* aux->prog still points to the fp_other one, so
|
* when promoting the clone to the real program,
|
* this still needs to be adapted.
|
*/
|
memcpy(fp, fp_other, fp_other->pages * PAGE_SIZE);
|
}
|
|
return fp;
|
}
|
|
static void bpf_prog_clone_free(struct bpf_prog *fp)
|
{
|
/* aux was stolen by the other clone, so we cannot free
|
* it from this path! It will be freed eventually by the
|
* other program on release.
|
*
|
* At this point, we don't need a deferred release since
|
* clone is guaranteed to not be locked.
|
*/
|
fp->aux = NULL;
|
__bpf_prog_free(fp);
|
}
|
|
void bpf_jit_prog_release_other(struct bpf_prog *fp, struct bpf_prog *fp_other)
|
{
|
/* We have to repoint aux->prog to self, as we don't
|
* know whether fp here is the clone or the original.
|
*/
|
fp->aux->prog = fp;
|
bpf_prog_clone_free(fp_other);
|
}
|
|
struct bpf_prog *bpf_jit_blind_constants(struct bpf_prog *prog)
|
{
|
struct bpf_insn insn_buff[16], aux[2];
|
struct bpf_prog *clone, *tmp;
|
int insn_delta, insn_cnt;
|
struct bpf_insn *insn;
|
int i, rewritten;
|
|
if (!bpf_jit_blinding_enabled(prog) || prog->blinded)
|
return prog;
|
|
clone = bpf_prog_clone_create(prog, GFP_USER);
|
if (!clone)
|
return ERR_PTR(-ENOMEM);
|
|
insn_cnt = clone->len;
|
insn = clone->insnsi;
|
|
for (i = 0; i < insn_cnt; i++, insn++) {
|
/* We temporarily need to hold the original ld64 insn
|
* so that we can still access the first part in the
|
* second blinding run.
|
*/
|
if (insn[0].code == (BPF_LD | BPF_IMM | BPF_DW) &&
|
insn[1].code == 0)
|
memcpy(aux, insn, sizeof(aux));
|
|
rewritten = bpf_jit_blind_insn(insn, aux, insn_buff,
|
clone->aux->verifier_zext);
|
if (!rewritten)
|
continue;
|
|
tmp = bpf_patch_insn_single(clone, i, insn_buff, rewritten);
|
if (IS_ERR(tmp)) {
|
/* Patching may have repointed aux->prog during
|
* realloc from the original one, so we need to
|
* fix it up here on error.
|
*/
|
bpf_jit_prog_release_other(prog, clone);
|
return tmp;
|
}
|
|
clone = tmp;
|
insn_delta = rewritten - 1;
|
|
/* Walk new program and skip insns we just inserted. */
|
insn = clone->insnsi + i + insn_delta;
|
insn_cnt += insn_delta;
|
i += insn_delta;
|
}
|
|
clone->blinded = 1;
|
return clone;
|
}
|
#endif /* CONFIG_BPF_JIT */
|
|
/* Base function for offset calculation. Needs to go into .text section,
|
* therefore keeping it non-static as well; will also be used by JITs
|
* anyway later on, so do not let the compiler omit it. This also needs
|
* to go into kallsyms for correlation from e.g. bpftool, so naming
|
* must not change.
|
*/
|
noinline u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
|
{
|
return 0;
|
}
|
EXPORT_SYMBOL_GPL(__bpf_call_base);
|
|
/* All UAPI available opcodes. */
|
#define BPF_INSN_MAP(INSN_2, INSN_3) \
|
/* 32 bit ALU operations. */ \
|
/* Register based. */ \
|
INSN_3(ALU, ADD, X), \
|
INSN_3(ALU, SUB, X), \
|
INSN_3(ALU, AND, X), \
|
INSN_3(ALU, OR, X), \
|
INSN_3(ALU, LSH, X), \
|
INSN_3(ALU, RSH, X), \
|
INSN_3(ALU, XOR, X), \
|
INSN_3(ALU, MUL, X), \
|
INSN_3(ALU, MOV, X), \
|
INSN_3(ALU, ARSH, X), \
|
INSN_3(ALU, DIV, X), \
|
INSN_3(ALU, MOD, X), \
|
INSN_2(ALU, NEG), \
|
INSN_3(ALU, END, TO_BE), \
|
INSN_3(ALU, END, TO_LE), \
|
/* Immediate based. */ \
|
INSN_3(ALU, ADD, K), \
|
INSN_3(ALU, SUB, K), \
|
INSN_3(ALU, AND, K), \
|
INSN_3(ALU, OR, K), \
|
INSN_3(ALU, LSH, K), \
|
INSN_3(ALU, RSH, K), \
|
INSN_3(ALU, XOR, K), \
|
INSN_3(ALU, MUL, K), \
|
INSN_3(ALU, MOV, K), \
|
INSN_3(ALU, ARSH, K), \
|
INSN_3(ALU, DIV, K), \
|
INSN_3(ALU, MOD, K), \
|
/* 64 bit ALU operations. */ \
|
/* Register based. */ \
|
INSN_3(ALU64, ADD, X), \
|
INSN_3(ALU64, SUB, X), \
|
INSN_3(ALU64, AND, X), \
|
INSN_3(ALU64, OR, X), \
|
INSN_3(ALU64, LSH, X), \
|
INSN_3(ALU64, RSH, X), \
|
INSN_3(ALU64, XOR, X), \
|
INSN_3(ALU64, MUL, X), \
|
INSN_3(ALU64, MOV, X), \
|
INSN_3(ALU64, ARSH, X), \
|
INSN_3(ALU64, DIV, X), \
|
INSN_3(ALU64, MOD, X), \
|
INSN_2(ALU64, NEG), \
|
/* Immediate based. */ \
|
INSN_3(ALU64, ADD, K), \
|
INSN_3(ALU64, SUB, K), \
|
INSN_3(ALU64, AND, K), \
|
INSN_3(ALU64, OR, K), \
|
INSN_3(ALU64, LSH, K), \
|
INSN_3(ALU64, RSH, K), \
|
INSN_3(ALU64, XOR, K), \
|
INSN_3(ALU64, MUL, K), \
|
INSN_3(ALU64, MOV, K), \
|
INSN_3(ALU64, ARSH, K), \
|
INSN_3(ALU64, DIV, K), \
|
INSN_3(ALU64, MOD, K), \
|
/* Call instruction. */ \
|
INSN_2(JMP, CALL), \
|
/* Exit instruction. */ \
|
INSN_2(JMP, EXIT), \
|
/* 32-bit Jump instructions. */ \
|
/* Register based. */ \
|
INSN_3(JMP32, JEQ, X), \
|
INSN_3(JMP32, JNE, X), \
|
INSN_3(JMP32, JGT, X), \
|
INSN_3(JMP32, JLT, X), \
|
INSN_3(JMP32, JGE, X), \
|
INSN_3(JMP32, JLE, X), \
|
INSN_3(JMP32, JSGT, X), \
|
INSN_3(JMP32, JSLT, X), \
|
INSN_3(JMP32, JSGE, X), \
|
INSN_3(JMP32, JSLE, X), \
|
INSN_3(JMP32, JSET, X), \
|
/* Immediate based. */ \
|
INSN_3(JMP32, JEQ, K), \
|
INSN_3(JMP32, JNE, K), \
|
INSN_3(JMP32, JGT, K), \
|
INSN_3(JMP32, JLT, K), \
|
INSN_3(JMP32, JGE, K), \
|
INSN_3(JMP32, JLE, K), \
|
INSN_3(JMP32, JSGT, K), \
|
INSN_3(JMP32, JSLT, K), \
|
INSN_3(JMP32, JSGE, K), \
|
INSN_3(JMP32, JSLE, K), \
|
INSN_3(JMP32, JSET, K), \
|
/* Jump instructions. */ \
|
/* Register based. */ \
|
INSN_3(JMP, JEQ, X), \
|
INSN_3(JMP, JNE, X), \
|
INSN_3(JMP, JGT, X), \
|
INSN_3(JMP, JLT, X), \
|
INSN_3(JMP, JGE, X), \
|
INSN_3(JMP, JLE, X), \
|
INSN_3(JMP, JSGT, X), \
|
INSN_3(JMP, JSLT, X), \
|
INSN_3(JMP, JSGE, X), \
|
INSN_3(JMP, JSLE, X), \
|
INSN_3(JMP, JSET, X), \
|
/* Immediate based. */ \
|
INSN_3(JMP, JEQ, K), \
|
INSN_3(JMP, JNE, K), \
|
INSN_3(JMP, JGT, K), \
|
INSN_3(JMP, JLT, K), \
|
INSN_3(JMP, JGE, K), \
|
INSN_3(JMP, JLE, K), \
|
INSN_3(JMP, JSGT, K), \
|
INSN_3(JMP, JSLT, K), \
|
INSN_3(JMP, JSGE, K), \
|
INSN_3(JMP, JSLE, K), \
|
INSN_3(JMP, JSET, K), \
|
INSN_2(JMP, JA), \
|
/* Store instructions. */ \
|
/* Register based. */ \
|
INSN_3(STX, MEM, B), \
|
INSN_3(STX, MEM, H), \
|
INSN_3(STX, MEM, W), \
|
INSN_3(STX, MEM, DW), \
|
INSN_3(STX, XADD, W), \
|
INSN_3(STX, XADD, DW), \
|
/* Immediate based. */ \
|
INSN_3(ST, MEM, B), \
|
INSN_3(ST, MEM, H), \
|
INSN_3(ST, MEM, W), \
|
INSN_3(ST, MEM, DW), \
|
/* Load instructions. */ \
|
/* Register based. */ \
|
INSN_3(LDX, MEM, B), \
|
INSN_3(LDX, MEM, H), \
|
INSN_3(LDX, MEM, W), \
|
INSN_3(LDX, MEM, DW), \
|
/* Immediate based. */ \
|
INSN_3(LD, IMM, DW)
|
|
bool bpf_opcode_in_insntable(u8 code)
|
{
|
#define BPF_INSN_2_TBL(x, y) [BPF_##x | BPF_##y] = true
|
#define BPF_INSN_3_TBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = true
|
static const bool public_insntable[256] = {
|
[0 ... 255] = false,
|
/* Now overwrite non-defaults ... */
|
BPF_INSN_MAP(BPF_INSN_2_TBL, BPF_INSN_3_TBL),
|
/* UAPI exposed, but rewritten opcodes. cBPF carry-over. */
|
[BPF_LD | BPF_ABS | BPF_B] = true,
|
[BPF_LD | BPF_ABS | BPF_H] = true,
|
[BPF_LD | BPF_ABS | BPF_W] = true,
|
[BPF_LD | BPF_IND | BPF_B] = true,
|
[BPF_LD | BPF_IND | BPF_H] = true,
|
[BPF_LD | BPF_IND | BPF_W] = true,
|
};
|
#undef BPF_INSN_3_TBL
|
#undef BPF_INSN_2_TBL
|
return public_insntable[code];
|
}
|
|
#ifndef CONFIG_BPF_JIT_ALWAYS_ON
|
u64 __weak bpf_probe_read_kernel(void *dst, u32 size, const void *unsafe_ptr)
|
{
|
memset(dst, 0, size);
|
return -EFAULT;
|
}
|
|
/**
|
* __bpf_prog_run - run eBPF program on a given context
|
* @regs: is the array of MAX_BPF_EXT_REG eBPF pseudo-registers
|
* @insn: is the array of eBPF instructions
|
* @stack: is the eBPF storage stack
|
*
|
* Decode and execute eBPF instructions.
|
*/
|
static u64 ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn, u64 *stack)
|
{
|
#define BPF_INSN_2_LBL(x, y) [BPF_##x | BPF_##y] = &&x##_##y
|
#define BPF_INSN_3_LBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = &&x##_##y##_##z
|
static const void * const jumptable[256] __annotate_jump_table = {
|
[0 ... 255] = &&default_label,
|
/* Now overwrite non-defaults ... */
|
BPF_INSN_MAP(BPF_INSN_2_LBL, BPF_INSN_3_LBL),
|
/* Non-UAPI available opcodes. */
|
[BPF_JMP | BPF_CALL_ARGS] = &&JMP_CALL_ARGS,
|
[BPF_JMP | BPF_TAIL_CALL] = &&JMP_TAIL_CALL,
|
[BPF_ST | BPF_NOSPEC] = &&ST_NOSPEC,
|
[BPF_LDX | BPF_PROBE_MEM | BPF_B] = &&LDX_PROBE_MEM_B,
|
[BPF_LDX | BPF_PROBE_MEM | BPF_H] = &&LDX_PROBE_MEM_H,
|
[BPF_LDX | BPF_PROBE_MEM | BPF_W] = &&LDX_PROBE_MEM_W,
|
[BPF_LDX | BPF_PROBE_MEM | BPF_DW] = &&LDX_PROBE_MEM_DW,
|
};
|
#undef BPF_INSN_3_LBL
|
#undef BPF_INSN_2_LBL
|
u32 tail_call_cnt = 0;
|
|
#define CONT ({ insn++; goto select_insn; })
|
#define CONT_JMP ({ insn++; goto select_insn; })
|
|
select_insn:
|
goto *jumptable[insn->code];
|
|
/* Explicitly mask the register-based shift amounts with 63 or 31
|
* to avoid undefined behavior. Normally this won't affect the
|
* generated code, for example, in case of native 64 bit archs such
|
* as x86-64 or arm64, the compiler is optimizing the AND away for
|
* the interpreter. In case of JITs, each of the JIT backends compiles
|
* the BPF shift operations to machine instructions which produce
|
* implementation-defined results in such a case; the resulting
|
* contents of the register may be arbitrary, but program behaviour
|
* as a whole remains defined. In other words, in case of JIT backends,
|
* the AND must /not/ be added to the emitted LSH/RSH/ARSH translation.
|
*/
|
/* ALU (shifts) */
|
#define SHT(OPCODE, OP) \
|
ALU64_##OPCODE##_X: \
|
DST = DST OP (SRC & 63); \
|
CONT; \
|
ALU_##OPCODE##_X: \
|
DST = (u32) DST OP ((u32) SRC & 31); \
|
CONT; \
|
ALU64_##OPCODE##_K: \
|
DST = DST OP IMM; \
|
CONT; \
|
ALU_##OPCODE##_K: \
|
DST = (u32) DST OP (u32) IMM; \
|
CONT;
|
/* ALU (rest) */
|
#define ALU(OPCODE, OP) \
|
ALU64_##OPCODE##_X: \
|
DST = DST OP SRC; \
|
CONT; \
|
ALU_##OPCODE##_X: \
|
DST = (u32) DST OP (u32) SRC; \
|
CONT; \
|
ALU64_##OPCODE##_K: \
|
DST = DST OP IMM; \
|
CONT; \
|
ALU_##OPCODE##_K: \
|
DST = (u32) DST OP (u32) IMM; \
|
CONT;
|
ALU(ADD, +)
|
ALU(SUB, -)
|
ALU(AND, &)
|
ALU(OR, |)
|
ALU(XOR, ^)
|
ALU(MUL, *)
|
SHT(LSH, <<)
|
SHT(RSH, >>)
|
#undef SHT
|
#undef ALU
|
ALU_NEG:
|
DST = (u32) -DST;
|
CONT;
|
ALU64_NEG:
|
DST = -DST;
|
CONT;
|
ALU_MOV_X:
|
DST = (u32) SRC;
|
CONT;
|
ALU_MOV_K:
|
DST = (u32) IMM;
|
CONT;
|
ALU64_MOV_X:
|
DST = SRC;
|
CONT;
|
ALU64_MOV_K:
|
DST = IMM;
|
CONT;
|
LD_IMM_DW:
|
DST = (u64) (u32) insn[0].imm | ((u64) (u32) insn[1].imm) << 32;
|
insn++;
|
CONT;
|
ALU_ARSH_X:
|
DST = (u64) (u32) (((s32) DST) >> (SRC & 31));
|
CONT;
|
ALU_ARSH_K:
|
DST = (u64) (u32) (((s32) DST) >> IMM);
|
CONT;
|
ALU64_ARSH_X:
|
(*(s64 *) &DST) >>= (SRC & 63);
|
CONT;
|
ALU64_ARSH_K:
|
(*(s64 *) &DST) >>= IMM;
|
CONT;
|
ALU64_MOD_X:
|
div64_u64_rem(DST, SRC, &AX);
|
DST = AX;
|
CONT;
|
ALU_MOD_X:
|
AX = (u32) DST;
|
DST = do_div(AX, (u32) SRC);
|
CONT;
|
ALU64_MOD_K:
|
div64_u64_rem(DST, IMM, &AX);
|
DST = AX;
|
CONT;
|
ALU_MOD_K:
|
AX = (u32) DST;
|
DST = do_div(AX, (u32) IMM);
|
CONT;
|
ALU64_DIV_X:
|
DST = div64_u64(DST, SRC);
|
CONT;
|
ALU_DIV_X:
|
AX = (u32) DST;
|
do_div(AX, (u32) SRC);
|
DST = (u32) AX;
|
CONT;
|
ALU64_DIV_K:
|
DST = div64_u64(DST, IMM);
|
CONT;
|
ALU_DIV_K:
|
AX = (u32) DST;
|
do_div(AX, (u32) IMM);
|
DST = (u32) AX;
|
CONT;
|
ALU_END_TO_BE:
|
switch (IMM) {
|
case 16:
|
DST = (__force u16) cpu_to_be16(DST);
|
break;
|
case 32:
|
DST = (__force u32) cpu_to_be32(DST);
|
break;
|
case 64:
|
DST = (__force u64) cpu_to_be64(DST);
|
break;
|
}
|
CONT;
|
ALU_END_TO_LE:
|
switch (IMM) {
|
case 16:
|
DST = (__force u16) cpu_to_le16(DST);
|
break;
|
case 32:
|
DST = (__force u32) cpu_to_le32(DST);
|
break;
|
case 64:
|
DST = (__force u64) cpu_to_le64(DST);
|
break;
|
}
|
CONT;
|
|
/* CALL */
|
JMP_CALL:
|
/* Function call scratches BPF_R1-BPF_R5 registers,
|
* preserves BPF_R6-BPF_R9, and stores return value
|
* into BPF_R0.
|
*/
|
BPF_R0 = (__bpf_call_base + insn->imm)(BPF_R1, BPF_R2, BPF_R3,
|
BPF_R4, BPF_R5);
|
CONT;
|
|
JMP_CALL_ARGS:
|
BPF_R0 = (__bpf_call_base_args + insn->imm)(BPF_R1, BPF_R2,
|
BPF_R3, BPF_R4,
|
BPF_R5,
|
insn + insn->off + 1);
|
CONT;
|
|
JMP_TAIL_CALL: {
|
struct bpf_map *map = (struct bpf_map *) (unsigned long) BPF_R2;
|
struct bpf_array *array = container_of(map, struct bpf_array, map);
|
struct bpf_prog *prog;
|
u32 index = BPF_R3;
|
|
if (unlikely(index >= array->map.max_entries))
|
goto out;
|
if (unlikely(tail_call_cnt > MAX_TAIL_CALL_CNT))
|
goto out;
|
|
tail_call_cnt++;
|
|
prog = READ_ONCE(array->ptrs[index]);
|
if (!prog)
|
goto out;
|
|
/* ARG1 at this point is guaranteed to point to CTX from
|
* the verifier side due to the fact that the tail call is
|
* handled like a helper, that is, bpf_tail_call_proto,
|
* where arg1_type is ARG_PTR_TO_CTX.
|
*/
|
insn = prog->insnsi;
|
goto select_insn;
|
out:
|
CONT;
|
}
|
JMP_JA:
|
insn += insn->off;
|
CONT;
|
JMP_EXIT:
|
return BPF_R0;
|
/* JMP */
|
#define COND_JMP(SIGN, OPCODE, CMP_OP) \
|
JMP_##OPCODE##_X: \
|
if ((SIGN##64) DST CMP_OP (SIGN##64) SRC) { \
|
insn += insn->off; \
|
CONT_JMP; \
|
} \
|
CONT; \
|
JMP32_##OPCODE##_X: \
|
if ((SIGN##32) DST CMP_OP (SIGN##32) SRC) { \
|
insn += insn->off; \
|
CONT_JMP; \
|
} \
|
CONT; \
|
JMP_##OPCODE##_K: \
|
if ((SIGN##64) DST CMP_OP (SIGN##64) IMM) { \
|
insn += insn->off; \
|
CONT_JMP; \
|
} \
|
CONT; \
|
JMP32_##OPCODE##_K: \
|
if ((SIGN##32) DST CMP_OP (SIGN##32) IMM) { \
|
insn += insn->off; \
|
CONT_JMP; \
|
} \
|
CONT;
|
COND_JMP(u, JEQ, ==)
|
COND_JMP(u, JNE, !=)
|
COND_JMP(u, JGT, >)
|
COND_JMP(u, JLT, <)
|
COND_JMP(u, JGE, >=)
|
COND_JMP(u, JLE, <=)
|
COND_JMP(u, JSET, &)
|
COND_JMP(s, JSGT, >)
|
COND_JMP(s, JSLT, <)
|
COND_JMP(s, JSGE, >=)
|
COND_JMP(s, JSLE, <=)
|
#undef COND_JMP
|
/* ST, STX and LDX*/
|
ST_NOSPEC:
|
/* Speculation barrier for mitigating Speculative Store Bypass.
|
* In case of arm64, we rely on the firmware mitigation as
|
* controlled via the ssbd kernel parameter. Whenever the
|
* mitigation is enabled, it works for all of the kernel code
|
* with no need to provide any additional instructions here.
|
* In case of x86, we use 'lfence' insn for mitigation. We
|
* reuse preexisting logic from Spectre v1 mitigation that
|
* happens to produce the required code on x86 for v4 as well.
|
*/
|
#ifdef CONFIG_X86
|
barrier_nospec();
|
#endif
|
CONT;
|
#define LDST(SIZEOP, SIZE) \
|
STX_MEM_##SIZEOP: \
|
*(SIZE *)(unsigned long) (DST + insn->off) = SRC; \
|
CONT; \
|
ST_MEM_##SIZEOP: \
|
*(SIZE *)(unsigned long) (DST + insn->off) = IMM; \
|
CONT; \
|
LDX_MEM_##SIZEOP: \
|
DST = *(SIZE *)(unsigned long) (SRC + insn->off); \
|
CONT; \
|
LDX_PROBE_MEM_##SIZEOP: \
|
bpf_probe_read_kernel(&DST, sizeof(SIZE), \
|
(const void *)(long) (SRC + insn->off)); \
|
DST = *((SIZE *)&DST); \
|
CONT;
|
|
LDST(B, u8)
|
LDST(H, u16)
|
LDST(W, u32)
|
LDST(DW, u64)
|
#undef LDST
|
|
STX_XADD_W: /* lock xadd *(u32 *)(dst_reg + off16) += src_reg */
|
atomic_add((u32) SRC, (atomic_t *)(unsigned long)
|
(DST + insn->off));
|
CONT;
|
STX_XADD_DW: /* lock xadd *(u64 *)(dst_reg + off16) += src_reg */
|
atomic64_add((u64) SRC, (atomic64_t *)(unsigned long)
|
(DST + insn->off));
|
CONT;
|
|
default_label:
|
/* If we ever reach this, we have a bug somewhere. Die hard here
|
* instead of just returning 0; we could be somewhere in a subprog,
|
* so execution could continue otherwise which we do /not/ want.
|
*
|
* Note, verifier whitelists all opcodes in bpf_opcode_in_insntable().
|
*/
|
pr_warn("BPF interpreter: unknown opcode %02x\n", insn->code);
|
BUG_ON(1);
|
return 0;
|
}
|
|
#define PROG_NAME(stack_size) __bpf_prog_run##stack_size
|
#define DEFINE_BPF_PROG_RUN(stack_size) \
|
static unsigned int PROG_NAME(stack_size)(const void *ctx, const struct bpf_insn *insn) \
|
{ \
|
u64 stack[stack_size / sizeof(u64)]; \
|
u64 regs[MAX_BPF_EXT_REG]; \
|
\
|
FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \
|
ARG1 = (u64) (unsigned long) ctx; \
|
return ___bpf_prog_run(regs, insn, stack); \
|
}
|
|
#define PROG_NAME_ARGS(stack_size) __bpf_prog_run_args##stack_size
|
#define DEFINE_BPF_PROG_RUN_ARGS(stack_size) \
|
static u64 PROG_NAME_ARGS(stack_size)(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5, \
|
const struct bpf_insn *insn) \
|
{ \
|
u64 stack[stack_size / sizeof(u64)]; \
|
u64 regs[MAX_BPF_EXT_REG]; \
|
\
|
FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \
|
BPF_R1 = r1; \
|
BPF_R2 = r2; \
|
BPF_R3 = r3; \
|
BPF_R4 = r4; \
|
BPF_R5 = r5; \
|
return ___bpf_prog_run(regs, insn, stack); \
|
}
|
|
#define EVAL1(FN, X) FN(X)
|
#define EVAL2(FN, X, Y...) FN(X) EVAL1(FN, Y)
|
#define EVAL3(FN, X, Y...) FN(X) EVAL2(FN, Y)
|
#define EVAL4(FN, X, Y...) FN(X) EVAL3(FN, Y)
|
#define EVAL5(FN, X, Y...) FN(X) EVAL4(FN, Y)
|
#define EVAL6(FN, X, Y...) FN(X) EVAL5(FN, Y)
|
|
EVAL6(DEFINE_BPF_PROG_RUN, 32, 64, 96, 128, 160, 192);
|
EVAL6(DEFINE_BPF_PROG_RUN, 224, 256, 288, 320, 352, 384);
|
EVAL4(DEFINE_BPF_PROG_RUN, 416, 448, 480, 512);
|
|
EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 32, 64, 96, 128, 160, 192);
|
EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 224, 256, 288, 320, 352, 384);
|
EVAL4(DEFINE_BPF_PROG_RUN_ARGS, 416, 448, 480, 512);
|
|
#define PROG_NAME_LIST(stack_size) PROG_NAME(stack_size),
|
|
static unsigned int (*interpreters[])(const void *ctx,
|
const struct bpf_insn *insn) = {
|
EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192)
|
EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384)
|
EVAL4(PROG_NAME_LIST, 416, 448, 480, 512)
|
};
|
#undef PROG_NAME_LIST
|
#define PROG_NAME_LIST(stack_size) PROG_NAME_ARGS(stack_size),
|
static u64 (*interpreters_args[])(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5,
|
const struct bpf_insn *insn) = {
|
EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192)
|
EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384)
|
EVAL4(PROG_NAME_LIST, 416, 448, 480, 512)
|
};
|
#undef PROG_NAME_LIST
|
|
void bpf_patch_call_args(struct bpf_insn *insn, u32 stack_depth)
|
{
|
stack_depth = max_t(u32, stack_depth, 1);
|
insn->off = (s16) insn->imm;
|
insn->imm = interpreters_args[(round_up(stack_depth, 32) / 32) - 1] -
|
__bpf_call_base_args;
|
insn->code = BPF_JMP | BPF_CALL_ARGS;
|
}
|
|
#else
|
static unsigned int __bpf_prog_ret0_warn(const void *ctx,
|
const struct bpf_insn *insn)
|
{
|
/* If this handler ever gets executed, then BPF_JIT_ALWAYS_ON
|
* is not working properly, so warn about it!
|
*/
|
WARN_ON_ONCE(1);
|
return 0;
|
}
|
#endif
|
|
bool bpf_prog_array_compatible(struct bpf_array *array,
|
const struct bpf_prog *fp)
|
{
|
bool ret;
|
|
if (fp->kprobe_override)
|
return false;
|
|
spin_lock(&array->aux->owner.lock);
|
|
if (!array->aux->owner.type) {
|
/* There's no owner yet where we could check for
|
* compatibility.
|
*/
|
array->aux->owner.type = fp->type;
|
array->aux->owner.jited = fp->jited;
|
ret = true;
|
} else {
|
ret = array->aux->owner.type == fp->type &&
|
array->aux->owner.jited == fp->jited;
|
}
|
spin_unlock(&array->aux->owner.lock);
|
return ret;
|
}
|
|
static int bpf_check_tail_call(const struct bpf_prog *fp)
|
{
|
struct bpf_prog_aux *aux = fp->aux;
|
int i, ret = 0;
|
|
mutex_lock(&aux->used_maps_mutex);
|
for (i = 0; i < aux->used_map_cnt; i++) {
|
struct bpf_map *map = aux->used_maps[i];
|
struct bpf_array *array;
|
|
if (map->map_type != BPF_MAP_TYPE_PROG_ARRAY)
|
continue;
|
|
array = container_of(map, struct bpf_array, map);
|
if (!bpf_prog_array_compatible(array, fp)) {
|
ret = -EINVAL;
|
goto out;
|
}
|
}
|
|
out:
|
mutex_unlock(&aux->used_maps_mutex);
|
return ret;
|
}
|
|
static void bpf_prog_select_func(struct bpf_prog *fp)
|
{
|
#ifndef CONFIG_BPF_JIT_ALWAYS_ON
|
u32 stack_depth = max_t(u32, fp->aux->stack_depth, 1);
|
|
fp->bpf_func = interpreters[(round_up(stack_depth, 32) / 32) - 1];
|
#else
|
fp->bpf_func = __bpf_prog_ret0_warn;
|
#endif
|
}
|
|
/**
|
* bpf_prog_select_runtime - select exec runtime for BPF program
|
* @fp: bpf_prog populated with internal BPF program
|
* @err: pointer to error variable
|
*
|
* Try to JIT eBPF program, if JIT is not available, use interpreter.
|
* The BPF program will be executed via BPF_PROG_RUN() macro.
|
*/
|
struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err)
|
{
|
/* In case of BPF to BPF calls, verifier did all the prep
|
* work with regards to JITing, etc.
|
*/
|
if (fp->bpf_func)
|
goto finalize;
|
|
bpf_prog_select_func(fp);
|
|
/* eBPF JITs can rewrite the program in case constant
|
* blinding is active. However, in case of error during
|
* blinding, bpf_int_jit_compile() must always return a
|
* valid program, which in this case would simply not
|
* be JITed, but falls back to the interpreter.
|
*/
|
if (!bpf_prog_is_dev_bound(fp->aux)) {
|
*err = bpf_prog_alloc_jited_linfo(fp);
|
if (*err)
|
return fp;
|
|
fp = bpf_int_jit_compile(fp);
|
if (!fp->jited) {
|
bpf_prog_free_jited_linfo(fp);
|
#ifdef CONFIG_BPF_JIT_ALWAYS_ON
|
*err = -ENOTSUPP;
|
return fp;
|
#endif
|
} else {
|
bpf_prog_free_unused_jited_linfo(fp);
|
}
|
} else {
|
*err = bpf_prog_offload_compile(fp);
|
if (*err)
|
return fp;
|
}
|
|
finalize:
|
bpf_prog_lock_ro(fp);
|
|
/* The tail call compatibility check can only be done at
|
* this late stage as we need to determine, if we deal
|
* with JITed or non JITed program concatenations and not
|
* all eBPF JITs might immediately support all features.
|
*/
|
*err = bpf_check_tail_call(fp);
|
|
return fp;
|
}
|
EXPORT_SYMBOL_GPL(bpf_prog_select_runtime);
|
|
static unsigned int __bpf_prog_ret1(const void *ctx,
|
const struct bpf_insn *insn)
|
{
|
return 1;
|
}
|
|
static struct bpf_prog_dummy {
|
struct bpf_prog prog;
|
} dummy_bpf_prog = {
|
.prog = {
|
.bpf_func = __bpf_prog_ret1,
|
},
|
};
|
|
/* to avoid allocating empty bpf_prog_array for cgroups that
|
* don't have bpf program attached use one global 'empty_prog_array'
|
* It will not be modified the caller of bpf_prog_array_alloc()
|
* (since caller requested prog_cnt == 0)
|
* that pointer should be 'freed' by bpf_prog_array_free()
|
*/
|
static struct {
|
struct bpf_prog_array hdr;
|
struct bpf_prog *null_prog;
|
} empty_prog_array = {
|
.null_prog = NULL,
|
};
|
|
struct bpf_prog_array *bpf_prog_array_alloc(u32 prog_cnt, gfp_t flags)
|
{
|
if (prog_cnt)
|
return kzalloc(sizeof(struct bpf_prog_array) +
|
sizeof(struct bpf_prog_array_item) *
|
(prog_cnt + 1),
|
flags);
|
|
return &empty_prog_array.hdr;
|
}
|
|
void bpf_prog_array_free(struct bpf_prog_array *progs)
|
{
|
if (!progs || progs == &empty_prog_array.hdr)
|
return;
|
kfree_rcu(progs, rcu);
|
}
|
|
int bpf_prog_array_length(struct bpf_prog_array *array)
|
{
|
struct bpf_prog_array_item *item;
|
u32 cnt = 0;
|
|
for (item = array->items; item->prog; item++)
|
if (item->prog != &dummy_bpf_prog.prog)
|
cnt++;
|
return cnt;
|
}
|
|
bool bpf_prog_array_is_empty(struct bpf_prog_array *array)
|
{
|
struct bpf_prog_array_item *item;
|
|
for (item = array->items; item->prog; item++)
|
if (item->prog != &dummy_bpf_prog.prog)
|
return false;
|
return true;
|
}
|
|
static bool bpf_prog_array_copy_core(struct bpf_prog_array *array,
|
u32 *prog_ids,
|
u32 request_cnt)
|
{
|
struct bpf_prog_array_item *item;
|
int i = 0;
|
|
for (item = array->items; item->prog; item++) {
|
if (item->prog == &dummy_bpf_prog.prog)
|
continue;
|
prog_ids[i] = item->prog->aux->id;
|
if (++i == request_cnt) {
|
item++;
|
break;
|
}
|
}
|
|
return !!(item->prog);
|
}
|
|
int bpf_prog_array_copy_to_user(struct bpf_prog_array *array,
|
__u32 __user *prog_ids, u32 cnt)
|
{
|
unsigned long err = 0;
|
bool nospc;
|
u32 *ids;
|
|
/* users of this function are doing:
|
* cnt = bpf_prog_array_length();
|
* if (cnt > 0)
|
* bpf_prog_array_copy_to_user(..., cnt);
|
* so below kcalloc doesn't need extra cnt > 0 check.
|
*/
|
ids = kcalloc(cnt, sizeof(u32), GFP_USER | __GFP_NOWARN);
|
if (!ids)
|
return -ENOMEM;
|
nospc = bpf_prog_array_copy_core(array, ids, cnt);
|
err = copy_to_user(prog_ids, ids, cnt * sizeof(u32));
|
kfree(ids);
|
if (err)
|
return -EFAULT;
|
if (nospc)
|
return -ENOSPC;
|
return 0;
|
}
|
|
void bpf_prog_array_delete_safe(struct bpf_prog_array *array,
|
struct bpf_prog *old_prog)
|
{
|
struct bpf_prog_array_item *item;
|
|
for (item = array->items; item->prog; item++)
|
if (item->prog == old_prog) {
|
WRITE_ONCE(item->prog, &dummy_bpf_prog.prog);
|
break;
|
}
|
}
|
|
/**
|
* bpf_prog_array_delete_safe_at() - Replaces the program at the given
|
* index into the program array with
|
* a dummy no-op program.
|
* @array: a bpf_prog_array
|
* @index: the index of the program to replace
|
*
|
* Skips over dummy programs, by not counting them, when calculating
|
* the position of the program to replace.
|
*
|
* Return:
|
* * 0 - Success
|
* * -EINVAL - Invalid index value. Must be a non-negative integer.
|
* * -ENOENT - Index out of range
|
*/
|
int bpf_prog_array_delete_safe_at(struct bpf_prog_array *array, int index)
|
{
|
return bpf_prog_array_update_at(array, index, &dummy_bpf_prog.prog);
|
}
|
|
/**
|
* bpf_prog_array_update_at() - Updates the program at the given index
|
* into the program array.
|
* @array: a bpf_prog_array
|
* @index: the index of the program to update
|
* @prog: the program to insert into the array
|
*
|
* Skips over dummy programs, by not counting them, when calculating
|
* the position of the program to update.
|
*
|
* Return:
|
* * 0 - Success
|
* * -EINVAL - Invalid index value. Must be a non-negative integer.
|
* * -ENOENT - Index out of range
|
*/
|
int bpf_prog_array_update_at(struct bpf_prog_array *array, int index,
|
struct bpf_prog *prog)
|
{
|
struct bpf_prog_array_item *item;
|
|
if (unlikely(index < 0))
|
return -EINVAL;
|
|
for (item = array->items; item->prog; item++) {
|
if (item->prog == &dummy_bpf_prog.prog)
|
continue;
|
if (!index) {
|
WRITE_ONCE(item->prog, prog);
|
return 0;
|
}
|
index--;
|
}
|
return -ENOENT;
|
}
|
|
int bpf_prog_array_copy(struct bpf_prog_array *old_array,
|
struct bpf_prog *exclude_prog,
|
struct bpf_prog *include_prog,
|
struct bpf_prog_array **new_array)
|
{
|
int new_prog_cnt, carry_prog_cnt = 0;
|
struct bpf_prog_array_item *existing;
|
struct bpf_prog_array *array;
|
bool found_exclude = false;
|
int new_prog_idx = 0;
|
|
/* Figure out how many existing progs we need to carry over to
|
* the new array.
|
*/
|
if (old_array) {
|
existing = old_array->items;
|
for (; existing->prog; existing++) {
|
if (existing->prog == exclude_prog) {
|
found_exclude = true;
|
continue;
|
}
|
if (existing->prog != &dummy_bpf_prog.prog)
|
carry_prog_cnt++;
|
if (existing->prog == include_prog)
|
return -EEXIST;
|
}
|
}
|
|
if (exclude_prog && !found_exclude)
|
return -ENOENT;
|
|
/* How many progs (not NULL) will be in the new array? */
|
new_prog_cnt = carry_prog_cnt;
|
if (include_prog)
|
new_prog_cnt += 1;
|
|
/* Do we have any prog (not NULL) in the new array? */
|
if (!new_prog_cnt) {
|
*new_array = NULL;
|
return 0;
|
}
|
|
/* +1 as the end of prog_array is marked with NULL */
|
array = bpf_prog_array_alloc(new_prog_cnt + 1, GFP_KERNEL);
|
if (!array)
|
return -ENOMEM;
|
|
/* Fill in the new prog array */
|
if (carry_prog_cnt) {
|
existing = old_array->items;
|
for (; existing->prog; existing++)
|
if (existing->prog != exclude_prog &&
|
existing->prog != &dummy_bpf_prog.prog) {
|
array->items[new_prog_idx++].prog =
|
existing->prog;
|
}
|
}
|
if (include_prog)
|
array->items[new_prog_idx++].prog = include_prog;
|
array->items[new_prog_idx].prog = NULL;
|
*new_array = array;
|
return 0;
|
}
|
|
int bpf_prog_array_copy_info(struct bpf_prog_array *array,
|
u32 *prog_ids, u32 request_cnt,
|
u32 *prog_cnt)
|
{
|
u32 cnt = 0;
|
|
if (array)
|
cnt = bpf_prog_array_length(array);
|
|
*prog_cnt = cnt;
|
|
/* return early if user requested only program count or nothing to copy */
|
if (!request_cnt || !cnt)
|
return 0;
|
|
/* this function is called under trace/bpf_trace.c: bpf_event_mutex */
|
return bpf_prog_array_copy_core(array, prog_ids, request_cnt) ? -ENOSPC
|
: 0;
|
}
|
|
void __bpf_free_used_maps(struct bpf_prog_aux *aux,
|
struct bpf_map **used_maps, u32 len)
|
{
|
struct bpf_map *map;
|
u32 i;
|
|
for (i = 0; i < len; i++) {
|
map = used_maps[i];
|
if (map->ops->map_poke_untrack)
|
map->ops->map_poke_untrack(map, aux);
|
bpf_map_put(map);
|
}
|
}
|
|
static void bpf_free_used_maps(struct bpf_prog_aux *aux)
|
{
|
__bpf_free_used_maps(aux, aux->used_maps, aux->used_map_cnt);
|
kfree(aux->used_maps);
|
}
|
|
static void bpf_prog_free_deferred(struct work_struct *work)
|
{
|
struct bpf_prog_aux *aux;
|
int i;
|
|
aux = container_of(work, struct bpf_prog_aux, work);
|
bpf_free_used_maps(aux);
|
if (bpf_prog_is_dev_bound(aux))
|
bpf_prog_offload_destroy(aux->prog);
|
#ifdef CONFIG_PERF_EVENTS
|
if (aux->prog->has_callchain_buf)
|
put_callchain_buffers();
|
#endif
|
if (aux->dst_trampoline)
|
bpf_trampoline_put(aux->dst_trampoline);
|
for (i = 0; i < aux->func_cnt; i++)
|
bpf_jit_free(aux->func[i]);
|
if (aux->func_cnt) {
|
kfree(aux->func);
|
bpf_prog_unlock_free(aux->prog);
|
} else {
|
bpf_jit_free(aux->prog);
|
}
|
}
|
|
/* Free internal BPF program */
|
void bpf_prog_free(struct bpf_prog *fp)
|
{
|
struct bpf_prog_aux *aux = fp->aux;
|
|
if (aux->dst_prog)
|
bpf_prog_put(aux->dst_prog);
|
INIT_WORK(&aux->work, bpf_prog_free_deferred);
|
schedule_work(&aux->work);
|
}
|
EXPORT_SYMBOL_GPL(bpf_prog_free);
|
|
/* RNG for unpriviledged user space with separated state from prandom_u32(). */
|
static DEFINE_PER_CPU(struct rnd_state, bpf_user_rnd_state);
|
|
void bpf_user_rnd_init_once(void)
|
{
|
prandom_init_once(&bpf_user_rnd_state);
|
}
|
|
BPF_CALL_0(bpf_user_rnd_u32)
|
{
|
/* Should someone ever have the rather unwise idea to use some
|
* of the registers passed into this function, then note that
|
* this function is called from native eBPF and classic-to-eBPF
|
* transformations. Register assignments from both sides are
|
* different, f.e. classic always sets fn(ctx, A, X) here.
|
*/
|
struct rnd_state *state;
|
u32 res;
|
|
state = &get_cpu_var(bpf_user_rnd_state);
|
res = prandom_u32_state(state);
|
put_cpu_var(bpf_user_rnd_state);
|
|
return res;
|
}
|
|
BPF_CALL_0(bpf_get_raw_cpu_id)
|
{
|
return raw_smp_processor_id();
|
}
|
|
/* Weak definitions of helper functions in case we don't have bpf syscall. */
|
const struct bpf_func_proto bpf_map_lookup_elem_proto __weak;
|
const struct bpf_func_proto bpf_map_update_elem_proto __weak;
|
const struct bpf_func_proto bpf_map_delete_elem_proto __weak;
|
const struct bpf_func_proto bpf_map_push_elem_proto __weak;
|
const struct bpf_func_proto bpf_map_pop_elem_proto __weak;
|
const struct bpf_func_proto bpf_map_peek_elem_proto __weak;
|
const struct bpf_func_proto bpf_spin_lock_proto __weak;
|
const struct bpf_func_proto bpf_spin_unlock_proto __weak;
|
const struct bpf_func_proto bpf_jiffies64_proto __weak;
|
|
const struct bpf_func_proto bpf_get_prandom_u32_proto __weak;
|
const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak;
|
const struct bpf_func_proto bpf_get_numa_node_id_proto __weak;
|
const struct bpf_func_proto bpf_ktime_get_ns_proto __weak;
|
const struct bpf_func_proto bpf_ktime_get_boot_ns_proto __weak;
|
|
const struct bpf_func_proto bpf_get_current_pid_tgid_proto __weak;
|
const struct bpf_func_proto bpf_get_current_uid_gid_proto __weak;
|
const struct bpf_func_proto bpf_get_current_comm_proto __weak;
|
const struct bpf_func_proto bpf_get_current_cgroup_id_proto __weak;
|
const struct bpf_func_proto bpf_get_current_ancestor_cgroup_id_proto __weak;
|
const struct bpf_func_proto bpf_get_local_storage_proto __weak;
|
const struct bpf_func_proto bpf_get_ns_current_pid_tgid_proto __weak;
|
const struct bpf_func_proto bpf_snprintf_btf_proto __weak;
|
const struct bpf_func_proto bpf_seq_printf_btf_proto __weak;
|
|
const struct bpf_func_proto * __weak bpf_get_trace_printk_proto(void)
|
{
|
return NULL;
|
}
|
|
u64 __weak
|
bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size,
|
void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy)
|
{
|
return -ENOTSUPP;
|
}
|
EXPORT_SYMBOL_GPL(bpf_event_output);
|
|
/* Always built-in helper functions. */
|
const struct bpf_func_proto bpf_tail_call_proto = {
|
.func = NULL,
|
.gpl_only = false,
|
.ret_type = RET_VOID,
|
.arg1_type = ARG_PTR_TO_CTX,
|
.arg2_type = ARG_CONST_MAP_PTR,
|
.arg3_type = ARG_ANYTHING,
|
};
|
|
/* Stub for JITs that only support cBPF. eBPF programs are interpreted.
|
* It is encouraged to implement bpf_int_jit_compile() instead, so that
|
* eBPF and implicitly also cBPF can get JITed!
|
*/
|
struct bpf_prog * __weak bpf_int_jit_compile(struct bpf_prog *prog)
|
{
|
return prog;
|
}
|
|
/* Stub for JITs that support eBPF. All cBPF code gets transformed into
|
* eBPF by the kernel and is later compiled by bpf_int_jit_compile().
|
*/
|
void __weak bpf_jit_compile(struct bpf_prog *prog)
|
{
|
}
|
|
bool __weak bpf_helper_changes_pkt_data(void *func)
|
{
|
return false;
|
}
|
|
/* Return TRUE if the JIT backend wants verifier to enable sub-register usage
|
* analysis code and wants explicit zero extension inserted by verifier.
|
* Otherwise, return FALSE.
|
*/
|
bool __weak bpf_jit_needs_zext(void)
|
{
|
return false;
|
}
|
|
/* To execute LD_ABS/LD_IND instructions __bpf_prog_run() may call
|
* skb_copy_bits(), so provide a weak definition of it for NET-less config.
|
*/
|
int __weak skb_copy_bits(const struct sk_buff *skb, int offset, void *to,
|
int len)
|
{
|
return -EFAULT;
|
}
|
|
int __weak bpf_arch_text_poke(void *ip, enum bpf_text_poke_type t,
|
void *addr1, void *addr2)
|
{
|
return -ENOTSUPP;
|
}
|
|
DEFINE_STATIC_KEY_FALSE(bpf_stats_enabled_key);
|
EXPORT_SYMBOL(bpf_stats_enabled_key);
|
|
/* All definitions of tracepoints related to BPF. */
|
#undef TRACE_INCLUDE_PATH
|
#define CREATE_TRACE_POINTS
|
#include <linux/bpf_trace.h>
|
|
EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_exception);
|
EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_bulk_tx);
|
