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/*
* Copyright (C) 2016 Netronome Systems, Inc.
*
* This software is dual licensed under the GNU General License Version 2,
* June 1991 as shown in the file COPYING in the top-level directory of this
* source tree or the BSD 2-Clause License provided below. You have the
* option to license this software under the complete terms of either license.
*
* The BSD 2-Clause License:
*
* Redistribution and use in source and binary forms, with or
* without modification, are permitted provided that the following
* conditions are met:
*
* 1. Redistributions of source code must retain the above
* copyright notice, this list of conditions and the following
* disclaimer.
*
* 2. Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials
* provided with the distribution.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#define pr_fmt(fmt) "NFP net bpf: " fmt
#include <linux/bpf.h>
#include <linux/bpf_verifier.h>
#include <linux/kernel.h>
#include <linux/pkt_cls.h>
#include "main.h"
static struct nfp_insn_meta *
nfp_bpf_goto_meta(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta,
unsigned int insn_idx, unsigned int n_insns)
{
unsigned int forward, backward, i;
backward = meta->n - insn_idx;
forward = insn_idx - meta->n;
if (min(forward, backward) > n_insns - insn_idx - 1) {
backward = n_insns - insn_idx - 1;
meta = nfp_prog_last_meta(nfp_prog);
}
if (min(forward, backward) > insn_idx && backward > insn_idx) {
forward = insn_idx;
meta = nfp_prog_first_meta(nfp_prog);
}
if (forward < backward)
for (i = 0; i < forward; i++)
meta = nfp_meta_next(meta);
else
for (i = 0; i < backward; i++)
meta = nfp_meta_prev(meta);
return meta;
}
static int
nfp_bpf_check_exit(struct nfp_prog *nfp_prog,
struct bpf_verifier_env *env)
{
const struct bpf_reg_state *reg0 = cur_regs(env) + BPF_REG_0;
u64 imm;
if (nfp_prog->type == BPF_PROG_TYPE_XDP)
return 0;
if (!(reg0->type == SCALAR_VALUE && tnum_is_const(reg0->var_off))) {
char tn_buf[48];
tnum_strn(tn_buf, sizeof(tn_buf), reg0->var_off);
pr_info("unsupported exit state: %d, var_off: %s\n",
reg0->type, tn_buf);
return -EINVAL;
}
imm = reg0->var_off.value;
if (nfp_prog->type == BPF_PROG_TYPE_SCHED_CLS &&
imm <= TC_ACT_REDIRECT &&
imm != TC_ACT_SHOT && imm != TC_ACT_STOLEN &&
imm != TC_ACT_QUEUED) {
pr_info("unsupported exit state: %d, imm: %llx\n",
reg0->type, imm);
return -EINVAL;
}
return 0;
}
static int
nfp_bpf_check_stack_access(struct nfp_prog *nfp_prog,
struct nfp_insn_meta *meta,
const struct bpf_reg_state *reg)
{
s32 old_off, new_off;
if (!tnum_is_const(reg->var_off)) {
pr_info("variable ptr stack access\n");
return -EINVAL;
}
if (meta->ptr.type == NOT_INIT)
return 0;
old_off = meta->ptr.off + meta->ptr.var_off.value;
new_off = reg->off + reg->var_off.value;
meta->ptr_not_const |= old_off != new_off;
if (!meta->ptr_not_const)
return 0;
if (old_off % 4 == new_off % 4)
return 0;
pr_info("stack access changed location was:%d is:%d\n",
old_off, new_off);
return -EINVAL;
}
static int
nfp_bpf_check_ptr(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta,
struct bpf_verifier_env *env, u8 reg_no)
{
const struct bpf_reg_state *reg = cur_regs(env) + reg_no;
int err;
if (reg->type != PTR_TO_CTX &&
reg->type != PTR_TO_STACK &&
reg->type != PTR_TO_PACKET) {
pr_info("unsupported ptr type: %d\n", reg->type);
return -EINVAL;
}
if (reg->type == PTR_TO_STACK) {
err = nfp_bpf_check_stack_access(nfp_prog, meta, reg);
if (err)
return err;
}
if (meta->ptr.type != NOT_INIT && meta->ptr.type != reg->type) {
pr_info("ptr type changed for instruction %d -> %d\n",
meta->ptr.type, reg->type);
return -EINVAL;
}
meta->ptr = *reg;
return 0;
}
static int
nfp_verify_insn(struct bpf_verifier_env *env, int insn_idx, int prev_insn_idx)
{
struct nfp_prog *nfp_prog = env->prog->aux->offload->dev_priv;
struct nfp_insn_meta *meta = nfp_prog->verifier_meta;
meta = nfp_bpf_goto_meta(nfp_prog, meta, insn_idx, env->prog->len);
nfp_prog->verifier_meta = meta;
if (meta->insn.src_reg >= MAX_BPF_REG ||
meta->insn.dst_reg >= MAX_BPF_REG) {
pr_err("program uses extended registers - jit hardening?\n");
return -EINVAL;
}
if (meta->insn.code == (BPF_JMP | BPF_EXIT))
return nfp_bpf_check_exit(nfp_prog, env);
if ((meta->insn.code & ~BPF_SIZE_MASK) == (BPF_LDX | BPF_MEM))
return nfp_bpf_check_ptr(nfp_prog, meta, env,
meta->insn.src_reg);
if ((meta->insn.code & ~BPF_SIZE_MASK) == (BPF_STX | BPF_MEM))
return nfp_bpf_check_ptr(nfp_prog, meta, env,
meta->insn.dst_reg);
return 0;
}
const struct bpf_ext_analyzer_ops nfp_bpf_analyzer_ops = {
.insn_hook = nfp_verify_insn,
};
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