215 lines
6.2 KiB
C
215 lines
6.2 KiB
C
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/* Copyright (c) 2011-2014 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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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*/
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#include <linux/bpf.h>
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#include "disasm.h"
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#define __BPF_FUNC_STR_FN(x) [BPF_FUNC_ ## x] = __stringify(bpf_ ## x)
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static const char * const func_id_str[] = {
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__BPF_FUNC_MAPPER(__BPF_FUNC_STR_FN)
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};
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#undef __BPF_FUNC_STR_FN
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const char *func_id_name(int id)
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{
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BUILD_BUG_ON(ARRAY_SIZE(func_id_str) != __BPF_FUNC_MAX_ID);
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if (id >= 0 && id < __BPF_FUNC_MAX_ID && func_id_str[id])
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return func_id_str[id];
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else
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return "unknown";
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}
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const char *const bpf_class_string[8] = {
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[BPF_LD] = "ld",
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[BPF_LDX] = "ldx",
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[BPF_ST] = "st",
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[BPF_STX] = "stx",
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[BPF_ALU] = "alu",
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[BPF_JMP] = "jmp",
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[BPF_RET] = "BUG",
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[BPF_ALU64] = "alu64",
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};
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const char *const bpf_alu_string[16] = {
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[BPF_ADD >> 4] = "+=",
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[BPF_SUB >> 4] = "-=",
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[BPF_MUL >> 4] = "*=",
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[BPF_DIV >> 4] = "/=",
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[BPF_OR >> 4] = "|=",
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[BPF_AND >> 4] = "&=",
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[BPF_LSH >> 4] = "<<=",
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[BPF_RSH >> 4] = ">>=",
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[BPF_NEG >> 4] = "neg",
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[BPF_MOD >> 4] = "%=",
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[BPF_XOR >> 4] = "^=",
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[BPF_MOV >> 4] = "=",
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[BPF_ARSH >> 4] = "s>>=",
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[BPF_END >> 4] = "endian",
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};
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static const char *const bpf_ldst_string[] = {
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[BPF_W >> 3] = "u32",
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[BPF_H >> 3] = "u16",
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[BPF_B >> 3] = "u8",
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[BPF_DW >> 3] = "u64",
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};
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static const char *const bpf_jmp_string[16] = {
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[BPF_JA >> 4] = "jmp",
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[BPF_JEQ >> 4] = "==",
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[BPF_JGT >> 4] = ">",
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[BPF_JLT >> 4] = "<",
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[BPF_JGE >> 4] = ">=",
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[BPF_JLE >> 4] = "<=",
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[BPF_JSET >> 4] = "&",
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[BPF_JNE >> 4] = "!=",
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[BPF_JSGT >> 4] = "s>",
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[BPF_JSLT >> 4] = "s<",
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[BPF_JSGE >> 4] = "s>=",
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[BPF_JSLE >> 4] = "s<=",
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[BPF_CALL >> 4] = "call",
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[BPF_EXIT >> 4] = "exit",
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};
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static void print_bpf_end_insn(bpf_insn_print_cb verbose,
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struct bpf_verifier_env *env,
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const struct bpf_insn *insn)
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{
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verbose(env, "(%02x) r%d = %s%d r%d\n", insn->code, insn->dst_reg,
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BPF_SRC(insn->code) == BPF_TO_BE ? "be" : "le",
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insn->imm, insn->dst_reg);
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}
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void print_bpf_insn(bpf_insn_print_cb verbose, struct bpf_verifier_env *env,
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const struct bpf_insn *insn, bool allow_ptr_leaks)
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{
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u8 class = BPF_CLASS(insn->code);
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if (class == BPF_ALU || class == BPF_ALU64) {
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if (BPF_OP(insn->code) == BPF_END) {
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if (class == BPF_ALU64)
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verbose(env, "BUG_alu64_%02x\n", insn->code);
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else
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print_bpf_end_insn(verbose, env, insn);
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} else if (BPF_OP(insn->code) == BPF_NEG) {
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verbose(env, "(%02x) r%d = %s-r%d\n",
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insn->code, insn->dst_reg,
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class == BPF_ALU ? "(u32) " : "",
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insn->dst_reg);
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} else if (BPF_SRC(insn->code) == BPF_X) {
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verbose(env, "(%02x) %sr%d %s %sr%d\n",
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insn->code, class == BPF_ALU ? "(u32) " : "",
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insn->dst_reg,
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bpf_alu_string[BPF_OP(insn->code) >> 4],
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class == BPF_ALU ? "(u32) " : "",
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insn->src_reg);
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} else {
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verbose(env, "(%02x) %sr%d %s %s%d\n",
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insn->code, class == BPF_ALU ? "(u32) " : "",
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insn->dst_reg,
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bpf_alu_string[BPF_OP(insn->code) >> 4],
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class == BPF_ALU ? "(u32) " : "",
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insn->imm);
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}
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} else if (class == BPF_STX) {
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if (BPF_MODE(insn->code) == BPF_MEM)
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verbose(env, "(%02x) *(%s *)(r%d %+d) = r%d\n",
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insn->code,
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bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
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insn->dst_reg,
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insn->off, insn->src_reg);
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else if (BPF_MODE(insn->code) == BPF_XADD)
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verbose(env, "(%02x) lock *(%s *)(r%d %+d) += r%d\n",
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insn->code,
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bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
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insn->dst_reg, insn->off,
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insn->src_reg);
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else
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verbose(env, "BUG_%02x\n", insn->code);
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} else if (class == BPF_ST) {
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if (BPF_MODE(insn->code) != BPF_MEM) {
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verbose(env, "BUG_st_%02x\n", insn->code);
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return;
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}
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verbose(env, "(%02x) *(%s *)(r%d %+d) = %d\n",
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insn->code,
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bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
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insn->dst_reg,
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insn->off, insn->imm);
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} else if (class == BPF_LDX) {
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if (BPF_MODE(insn->code) != BPF_MEM) {
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verbose(env, "BUG_ldx_%02x\n", insn->code);
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return;
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}
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verbose(env, "(%02x) r%d = *(%s *)(r%d %+d)\n",
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insn->code, insn->dst_reg,
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bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
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insn->src_reg, insn->off);
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} else if (class == BPF_LD) {
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if (BPF_MODE(insn->code) == BPF_ABS) {
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verbose(env, "(%02x) r0 = *(%s *)skb[%d]\n",
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insn->code,
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bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
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insn->imm);
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} else if (BPF_MODE(insn->code) == BPF_IND) {
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verbose(env, "(%02x) r0 = *(%s *)skb[r%d + %d]\n",
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insn->code,
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bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
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insn->src_reg, insn->imm);
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} else if (BPF_MODE(insn->code) == BPF_IMM &&
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BPF_SIZE(insn->code) == BPF_DW) {
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/* At this point, we already made sure that the second
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* part of the ldimm64 insn is accessible.
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*/
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u64 imm = ((u64)(insn + 1)->imm << 32) | (u32)insn->imm;
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bool map_ptr = insn->src_reg == BPF_PSEUDO_MAP_FD;
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if (map_ptr && !allow_ptr_leaks)
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imm = 0;
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verbose(env, "(%02x) r%d = 0x%llx\n", insn->code,
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insn->dst_reg, (unsigned long long)imm);
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} else {
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verbose(env, "BUG_ld_%02x\n", insn->code);
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return;
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}
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} else if (class == BPF_JMP) {
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u8 opcode = BPF_OP(insn->code);
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if (opcode == BPF_CALL) {
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verbose(env, "(%02x) call %s#%d\n", insn->code,
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func_id_name(insn->imm), insn->imm);
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} else if (insn->code == (BPF_JMP | BPF_JA)) {
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verbose(env, "(%02x) goto pc%+d\n",
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insn->code, insn->off);
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} else if (insn->code == (BPF_JMP | BPF_EXIT)) {
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verbose(env, "(%02x) exit\n", insn->code);
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} else if (BPF_SRC(insn->code) == BPF_X) {
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verbose(env, "(%02x) if r%d %s r%d goto pc%+d\n",
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insn->code, insn->dst_reg,
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bpf_jmp_string[BPF_OP(insn->code) >> 4],
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insn->src_reg, insn->off);
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} else {
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verbose(env, "(%02x) if r%d %s 0x%x goto pc%+d\n",
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insn->code, insn->dst_reg,
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bpf_jmp_string[BPF_OP(insn->code) >> 4],
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insn->imm, insn->off);
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}
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} else {
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verbose(env, "(%02x) %s\n",
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insn->code, bpf_class_string[class]);
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}
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}
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