/* * Copyright (C) 2016-2018 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. */ #include #include #include #include #include "../nfp_app.h" #include "../nfp_main.h" #include "fw.h" #include "main.h" #define pr_vlog(env, fmt, ...) \ bpf_verifier_log_write(env, "[nfp] " fmt, ##__VA_ARGS__) 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 void nfp_record_adjust_head(struct nfp_app_bpf *bpf, struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta, const struct bpf_reg_state *reg2) { unsigned int location = UINT_MAX; int imm; /* Datapath usually can give us guarantees on how much adjust head * can be done without the need for any checks. Optimize the simple * case where there is only one adjust head by a constant. */ if (reg2->type != SCALAR_VALUE || !tnum_is_const(reg2->var_off)) goto exit_set_location; imm = reg2->var_off.value; /* Translator will skip all checks, we need to guarantee min pkt len */ if (imm > ETH_ZLEN - ETH_HLEN) goto exit_set_location; if (imm > (int)bpf->adjust_head.guaranteed_add || imm < -bpf->adjust_head.guaranteed_sub) goto exit_set_location; if (nfp_prog->adjust_head_location) { /* Only one call per program allowed */ if (nfp_prog->adjust_head_location != meta->n) goto exit_set_location; if (meta->arg2.reg.var_off.value != imm) goto exit_set_location; } location = meta->n; exit_set_location: nfp_prog->adjust_head_location = location; } static bool nfp_bpf_map_update_value_ok(struct bpf_verifier_env *env) { const struct bpf_reg_state *reg1 = cur_regs(env) + BPF_REG_1; const struct bpf_reg_state *reg3 = cur_regs(env) + BPF_REG_3; struct bpf_offloaded_map *offmap; struct bpf_func_state *state; struct nfp_bpf_map *nfp_map; int off, i; state = env->cur_state->frame[reg3->frameno]; /* We need to record each time update happens with non-zero words, * in case such word is used in atomic operations. * Implicitly depend on nfp_bpf_stack_arg_ok(reg3) being run before. */ offmap = map_to_offmap(reg1->map_ptr); nfp_map = offmap->dev_priv; off = reg3->off + reg3->var_off.value; for (i = 0; i < offmap->map.value_size; i++) { struct bpf_stack_state *stack_entry; unsigned int soff; soff = -(off + i) - 1; stack_entry = &state->stack[soff / BPF_REG_SIZE]; if (stack_entry->slot_type[soff % BPF_REG_SIZE] == STACK_ZERO) continue; if (nfp_map->use_map[i / 4].type == NFP_MAP_USE_ATOMIC_CNT) { pr_vlog(env, "value at offset %d/%d may be non-zero, bpf_map_update_elem() is required to initialize atomic counters to zero to avoid offload endian issues\n", i, soff); return false; } nfp_map->use_map[i / 4].non_zero_update = 1; } return true; } static int nfp_bpf_stack_arg_ok(const char *fname, struct bpf_verifier_env *env, const struct bpf_reg_state *reg, struct nfp_bpf_reg_state *old_arg) { s64 off, old_off; if (reg->type != PTR_TO_STACK) { pr_vlog(env, "%s: unsupported ptr type %d\n", fname, reg->type); return false; } if (!tnum_is_const(reg->var_off)) { pr_vlog(env, "%s: variable pointer\n", fname); return false; } off = reg->var_off.value + reg->off; if (-off % 4) { pr_vlog(env, "%s: unaligned stack pointer %lld\n", fname, -off); return false; } /* Rest of the checks is only if we re-parse the same insn */ if (!old_arg) return true; old_off = old_arg->reg.var_off.value + old_arg->reg.off; old_arg->var_off |= off != old_off; return true; } static bool nfp_bpf_map_call_ok(const char *fname, struct bpf_verifier_env *env, struct nfp_insn_meta *meta, u32 helper_tgt, const struct bpf_reg_state *reg1) { if (!helper_tgt) { pr_vlog(env, "%s: not supported by FW\n", fname); return false; } return true; } static int nfp_bpf_check_call(struct nfp_prog *nfp_prog, struct bpf_verifier_env *env, struct nfp_insn_meta *meta) { const struct bpf_reg_state *reg1 = cur_regs(env) + BPF_REG_1; const struct bpf_reg_state *reg2 = cur_regs(env) + BPF_REG_2; const struct bpf_reg_state *reg3 = cur_regs(env) + BPF_REG_3; struct nfp_app_bpf *bpf = nfp_prog->bpf; u32 func_id = meta->insn.imm; switch (func_id) { case BPF_FUNC_xdp_adjust_head: if (!bpf->adjust_head.off_max) { pr_vlog(env, "adjust_head not supported by FW\n"); return -EOPNOTSUPP; } if (!(bpf->adjust_head.flags & NFP_BPF_ADJUST_HEAD_NO_META)) { pr_vlog(env, "adjust_head: FW requires shifting metadata, not supported by the driver\n"); return -EOPNOTSUPP; } nfp_record_adjust_head(bpf, nfp_prog, meta, reg2); break; case BPF_FUNC_xdp_adjust_tail: if (!bpf->adjust_tail) { pr_vlog(env, "adjust_tail not supported by FW\n"); return -EOPNOTSUPP; } break; case BPF_FUNC_map_lookup_elem: if (!nfp_bpf_map_call_ok("map_lookup", env, meta, bpf->helpers.map_lookup, reg1) || !nfp_bpf_stack_arg_ok("map_lookup", env, reg2, meta->func_id ? &meta->arg2 : NULL)) return -EOPNOTSUPP; break; case BPF_FUNC_map_update_elem: if (!nfp_bpf_map_call_ok("map_update", env, meta, bpf->helpers.map_update, reg1) || !nfp_bpf_stack_arg_ok("map_update", env, reg2, meta->func_id ? &meta->arg2 : NULL) || !nfp_bpf_stack_arg_ok("map_update", env, reg3, NULL) || !nfp_bpf_map_update_value_ok(env)) return -EOPNOTSUPP; break; case BPF_FUNC_map_delete_elem: if (!nfp_bpf_map_call_ok("map_delete", env, meta, bpf->helpers.map_delete, reg1) || !nfp_bpf_stack_arg_ok("map_delete", env, reg2, meta->func_id ? &meta->arg2 : NULL)) return -EOPNOTSUPP; break; case BPF_FUNC_get_prandom_u32: if (bpf->pseudo_random) break; pr_vlog(env, "bpf_get_prandom_u32(): FW doesn't support random number generation\n"); return -EOPNOTSUPP; case BPF_FUNC_perf_event_output: BUILD_BUG_ON(NFP_BPF_SCALAR_VALUE != SCALAR_VALUE || NFP_BPF_MAP_VALUE != PTR_TO_MAP_VALUE || NFP_BPF_STACK != PTR_TO_STACK || NFP_BPF_PACKET_DATA != PTR_TO_PACKET); if (!bpf->helpers.perf_event_output) { pr_vlog(env, "event_output: not supported by FW\n"); return -EOPNOTSUPP; } /* Force current CPU to make sure we can report the event * wherever we get the control message from FW. */ if (reg3->var_off.mask & BPF_F_INDEX_MASK || (reg3->var_off.value & BPF_F_INDEX_MASK) != BPF_F_CURRENT_CPU) { char tn_buf[48]; tnum_strn(tn_buf, sizeof(tn_buf), reg3->var_off); pr_vlog(env, "event_output: must use BPF_F_CURRENT_CPU, var_off: %s\n", tn_buf); return -EOPNOTSUPP; } /* Save space in meta, we don't care about arguments other * than 4th meta, shove it into arg1. */ reg1 = cur_regs(env) + BPF_REG_4; if (reg1->type != SCALAR_VALUE /* NULL ptr */ && reg1->type != PTR_TO_STACK && reg1->type != PTR_TO_MAP_VALUE && reg1->type != PTR_TO_PACKET) { pr_vlog(env, "event_output: unsupported ptr type: %d\n", reg1->type); return -EOPNOTSUPP; } if (reg1->type == PTR_TO_STACK && !nfp_bpf_stack_arg_ok("event_output", env, reg1, NULL)) return -EOPNOTSUPP; /* Warn user that on offload NFP may return success even if map * is not going to accept the event, since the event output is * fully async and device won't know the state of the map. * There is also FW limitation on the event length. * * Lost events will not show up on the perf ring, driver * won't see them at all. Events may also get reordered. */ dev_warn_once(&nfp_prog->bpf->app->pf->pdev->dev, "bpf: note: return codes and behavior of bpf_event_output() helper differs for offloaded programs!\n"); pr_vlog(env, "warning: return codes and behavior of event_output helper differ for offload!\n"); if (!meta->func_id) break; if (reg1->type != meta->arg1.type) { pr_vlog(env, "event_output: ptr type changed: %d %d\n", meta->arg1.type, reg1->type); return -EINVAL; } break; default: pr_vlog(env, "unsupported function id: %d\n", func_id); return -EOPNOTSUPP; } meta->func_id = func_id; meta->arg1 = *reg1; meta->arg2.reg = *reg2; return 0; } 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_vlog(env, "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_vlog(env, "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, struct bpf_verifier_env *env) { s32 old_off, new_off; if (!tnum_is_const(reg->var_off)) { pr_vlog(env, "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_vlog(env, "stack access changed location was:%d is:%d\n", old_off, new_off); return -EINVAL; } static const char *nfp_bpf_map_use_name(enum nfp_bpf_map_use use) { static const char * const names[] = { [NFP_MAP_UNUSED] = "unused", [NFP_MAP_USE_READ] = "read", [NFP_MAP_USE_WRITE] = "write", [NFP_MAP_USE_ATOMIC_CNT] = "atomic", }; if (use >= ARRAY_SIZE(names) || !names[use]) return "unknown"; return names[use]; } static int nfp_bpf_map_mark_used_one(struct bpf_verifier_env *env, struct nfp_bpf_map *nfp_map, unsigned int off, enum nfp_bpf_map_use use) { if (nfp_map->use_map[off / 4].type != NFP_MAP_UNUSED && nfp_map->use_map[off / 4].type != use) { pr_vlog(env, "map value use type conflict %s vs %s off: %u\n", nfp_bpf_map_use_name(nfp_map->use_map[off / 4].type), nfp_bpf_map_use_name(use), off); return -EOPNOTSUPP; } if (nfp_map->use_map[off / 4].non_zero_update && use == NFP_MAP_USE_ATOMIC_CNT) { pr_vlog(env, "atomic counter in map value may already be initialized to non-zero value off: %u\n", off); return -EOPNOTSUPP; } nfp_map->use_map[off / 4].type = use; return 0; } static int nfp_bpf_map_mark_used(struct bpf_verifier_env *env, struct nfp_insn_meta *meta, const struct bpf_reg_state *reg, enum nfp_bpf_map_use use) { struct bpf_offloaded_map *offmap; struct nfp_bpf_map *nfp_map; unsigned int size, off; int i, err; if (!tnum_is_const(reg->var_off)) { pr_vlog(env, "map value offset is variable\n"); return -EOPNOTSUPP; } off = reg->var_off.value + meta->insn.off + reg->off; size = BPF_LDST_BYTES(&meta->insn); offmap = map_to_offmap(reg->map_ptr); nfp_map = offmap->dev_priv; if (off + size > offmap->map.value_size) { pr_vlog(env, "map value access out-of-bounds\n"); return -EINVAL; } for (i = 0; i < size; i += 4 - (off + i) % 4) { err = nfp_bpf_map_mark_used_one(env, nfp_map, off + i, use); if (err) return err; } return 0; } 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_MAP_VALUE && reg->type != PTR_TO_PACKET) { pr_vlog(env, "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, env); if (err) return err; } if (reg->type == PTR_TO_MAP_VALUE) { if (is_mbpf_load(meta)) { err = nfp_bpf_map_mark_used(env, meta, reg, NFP_MAP_USE_READ); if (err) return err; } if (is_mbpf_store(meta)) { pr_vlog(env, "map writes not supported\n"); return -EOPNOTSUPP; } if (is_mbpf_xadd(meta)) { err = nfp_bpf_map_mark_used(env, meta, reg, NFP_MAP_USE_ATOMIC_CNT); if (err) return err; } } if (meta->ptr.type != NOT_INIT && meta->ptr.type != reg->type) { pr_vlog(env, "ptr type changed for instruction %d -> %d\n", meta->ptr.type, reg->type); return -EINVAL; } meta->ptr = *reg; return 0; } static int nfp_bpf_check_store(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta, struct bpf_verifier_env *env) { const struct bpf_reg_state *reg = cur_regs(env) + meta->insn.dst_reg; if (reg->type == PTR_TO_CTX) { if (nfp_prog->type == BPF_PROG_TYPE_XDP) { /* XDP ctx accesses must be 4B in size */ switch (meta->insn.off) { case offsetof(struct xdp_md, rx_queue_index): if (nfp_prog->bpf->queue_select) goto exit_check_ptr; pr_vlog(env, "queue selection not supported by FW\n"); return -EOPNOTSUPP; } } pr_vlog(env, "unsupported store to context field\n"); return -EOPNOTSUPP; } exit_check_ptr: return nfp_bpf_check_ptr(nfp_prog, meta, env, meta->insn.dst_reg); } static int nfp_bpf_check_xadd(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta, struct bpf_verifier_env *env) { const struct bpf_reg_state *sreg = cur_regs(env) + meta->insn.src_reg; const struct bpf_reg_state *dreg = cur_regs(env) + meta->insn.dst_reg; if (dreg->type != PTR_TO_MAP_VALUE) { pr_vlog(env, "atomic add not to a map value pointer: %d\n", dreg->type); return -EOPNOTSUPP; } if (sreg->type != SCALAR_VALUE) { pr_vlog(env, "atomic add not of a scalar: %d\n", sreg->type); return -EOPNOTSUPP; } meta->xadd_over_16bit |= sreg->var_off.value > 0xffff || sreg->var_off.mask > 0xffff; meta->xadd_maybe_16bit |= (sreg->var_off.value & ~sreg->var_off.mask) <= 0xffff; return nfp_bpf_check_ptr(nfp_prog, meta, env, meta->insn.dst_reg); } static int nfp_bpf_check_alu(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta, struct bpf_verifier_env *env) { const struct bpf_reg_state *sreg = cur_regs(env) + meta->insn.src_reg; const struct bpf_reg_state *dreg = cur_regs(env) + meta->insn.dst_reg; meta->umin_src = min(meta->umin_src, sreg->umin_value); meta->umax_src = max(meta->umax_src, sreg->umax_value); meta->umin_dst = min(meta->umin_dst, dreg->umin_value); meta->umax_dst = max(meta->umax_dst, dreg->umax_value); /* NFP supports u16 and u32 multiplication. * * For ALU64, if either operand is beyond u32's value range, we reject * it. One thing to note, if the source operand is BPF_K, then we need * to check "imm" field directly, and we'd reject it if it is negative. * Because for ALU64, "imm" (with s32 type) is expected to be sign * extended to s64 which NFP mul doesn't support. * * For ALU32, it is fine for "imm" be negative though, because the * result is 32-bits and there is no difference on the low halve of * the result for signed/unsigned mul, so we will get correct result. */ if (is_mbpf_mul(meta)) { if (meta->umax_dst > U32_MAX) { pr_vlog(env, "multiplier is not within u32 value range\n"); return -EINVAL; } if (mbpf_src(meta) == BPF_X && meta->umax_src > U32_MAX) { pr_vlog(env, "multiplicand is not within u32 value range\n"); return -EINVAL; } if (mbpf_class(meta) == BPF_ALU64 && mbpf_src(meta) == BPF_K && meta->insn.imm < 0) { pr_vlog(env, "sign extended multiplicand won't be within u32 value range\n"); return -EINVAL; } } /* NFP doesn't have divide instructions, we support divide by constant * through reciprocal multiplication. Given NFP support multiplication * no bigger than u32, we'd require divisor and dividend no bigger than * that as well. * * Also eBPF doesn't support signed divide and has enforced this on C * language level by failing compilation. However LLVM assembler hasn't * enforced this, so it is possible for negative constant to leak in as * a BPF_K operand through assembly code, we reject such cases as well. */ if (is_mbpf_div(meta)) { if (meta->umax_dst > U32_MAX) { pr_vlog(env, "dividend is not within u32 value range\n"); return -EINVAL; } if (mbpf_src(meta) == BPF_X) { if (meta->umin_src != meta->umax_src) { pr_vlog(env, "divisor is not constant\n"); return -EINVAL; } if (meta->umax_src > U32_MAX) { pr_vlog(env, "divisor is not within u32 value range\n"); return -EINVAL; } } if (mbpf_src(meta) == BPF_K && meta->insn.imm < 0) { pr_vlog(env, "divide by negative constant is not supported\n"); return -EINVAL; } } 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 (!nfp_bpf_supported_opcode(meta->insn.code)) { pr_vlog(env, "instruction %#02x not supported\n", meta->insn.code); return -EINVAL; } if (meta->insn.src_reg >= MAX_BPF_REG || meta->insn.dst_reg >= MAX_BPF_REG) { pr_vlog(env, "program uses extended registers - jit hardening?\n"); return -EINVAL; } if (meta->insn.code == (BPF_JMP | BPF_CALL)) return nfp_bpf_check_call(nfp_prog, env, meta); if (meta->insn.code == (BPF_JMP | BPF_EXIT)) return nfp_bpf_check_exit(nfp_prog, env); if (is_mbpf_load(meta)) return nfp_bpf_check_ptr(nfp_prog, meta, env, meta->insn.src_reg); if (is_mbpf_store(meta)) return nfp_bpf_check_store(nfp_prog, meta, env); if (is_mbpf_xadd(meta)) return nfp_bpf_check_xadd(nfp_prog, meta, env); if (is_mbpf_alu(meta)) return nfp_bpf_check_alu(nfp_prog, meta, env); return 0; } const struct bpf_prog_offload_ops nfp_bpf_analyzer_ops = { .insn_hook = nfp_verify_insn, };