diff options
Diffstat (limited to 'drivers/net/ethernet/netronome/nfp/bpf/verifier.c')
| -rw-r--r-- | drivers/net/ethernet/netronome/nfp/bpf/verifier.c | 174 |
1 files changed, 174 insertions, 0 deletions
diff --git a/drivers/net/ethernet/netronome/nfp/bpf/verifier.c b/drivers/net/ethernet/netronome/nfp/bpf/verifier.c new file mode 100644 index 000000000000..d696ba46f70a --- /dev/null +++ b/drivers/net/ethernet/netronome/nfp/bpf/verifier.c @@ -0,0 +1,174 @@ +/* + * 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" + +/* Analyzer/verifier definitions */ +struct nfp_bpf_analyzer_priv { + struct nfp_prog *prog; + struct nfp_insn_meta *meta; +}; + +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, + const struct bpf_verifier_env *env) +{ + const struct bpf_reg_state *reg0 = &env->cur_state.regs[0]; + + if (nfp_prog->act == NN_ACT_XDP) + return 0; + + if (reg0->type != CONST_IMM) { + pr_info("unsupported exit state: %d, imm: %llx\n", + reg0->type, reg0->imm); + return -EINVAL; + } + + if (nfp_prog->act != NN_ACT_DIRECT && + reg0->imm != 0 && (reg0->imm & ~0U) != ~0U) { + pr_info("unsupported exit state: %d, imm: %llx\n", + reg0->type, reg0->imm); + return -EINVAL; + } + + if (nfp_prog->act == NN_ACT_DIRECT && reg0->imm <= TC_ACT_REDIRECT && + reg0->imm != TC_ACT_SHOT && reg0->imm != TC_ACT_STOLEN && + reg0->imm != TC_ACT_QUEUED) { + pr_info("unsupported exit state: %d, imm: %llx\n", + reg0->type, reg0->imm); + return -EINVAL; + } + + return 0; +} + +static int +nfp_bpf_check_ctx_ptr(struct nfp_prog *nfp_prog, + const struct bpf_verifier_env *env, u8 reg) +{ + if (env->cur_state.regs[reg].type != PTR_TO_CTX) + return -EINVAL; + + return 0; +} + +static int +nfp_verify_insn(struct bpf_verifier_env *env, int insn_idx, int prev_insn_idx) +{ + struct nfp_bpf_analyzer_priv *priv = env->analyzer_priv; + struct nfp_insn_meta *meta = priv->meta; + + meta = nfp_bpf_goto_meta(priv->prog, meta, insn_idx, env->prog->len); + priv->meta = meta; + + if (meta->insn.src_reg == BPF_REG_10 || + meta->insn.dst_reg == BPF_REG_10) { + pr_err("stack not yet supported\n"); + return -EINVAL; + } + 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(priv->prog, env); + + if ((meta->insn.code & ~BPF_SIZE_MASK) == (BPF_LDX | BPF_MEM)) + return nfp_bpf_check_ctx_ptr(priv->prog, env, + meta->insn.src_reg); + if ((meta->insn.code & ~BPF_SIZE_MASK) == (BPF_STX | BPF_MEM)) + return nfp_bpf_check_ctx_ptr(priv->prog, env, + meta->insn.dst_reg); + + return 0; +} + +static const struct bpf_ext_analyzer_ops nfp_bpf_analyzer_ops = { + .insn_hook = nfp_verify_insn, +}; + +int nfp_prog_verify(struct nfp_prog *nfp_prog, struct bpf_prog *prog) +{ + struct nfp_bpf_analyzer_priv *priv; + int ret; + + priv = kzalloc(sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + priv->prog = nfp_prog; + priv->meta = nfp_prog_first_meta(nfp_prog); + + ret = bpf_analyzer(prog, &nfp_bpf_analyzer_ops, priv); + + kfree(priv); + + return ret; +} |