diff options
Diffstat (limited to 'kernel/bpf/verifier.c')
| -rw-r--r-- | kernel/bpf/verifier.c | 393 |
1 files changed, 329 insertions, 64 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 44e4ec1640f1..999bf36ffeb1 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -234,6 +234,12 @@ static bool bpf_pseudo_call(const struct bpf_insn *insn) insn->src_reg == BPF_PSEUDO_CALL; } +static bool bpf_pseudo_func(const struct bpf_insn *insn) +{ + return insn->code == (BPF_LD | BPF_IMM | BPF_DW) && + insn->src_reg == BPF_PSEUDO_FUNC; +} + struct bpf_call_arg_meta { struct bpf_map *map_ptr; bool raw_mode; @@ -248,6 +254,7 @@ struct bpf_call_arg_meta { u32 btf_id; struct btf *ret_btf; u32 ret_btf_id; + u32 subprogno; }; struct btf *btf_vmlinux; @@ -390,6 +397,24 @@ __printf(3, 4) static void verbose_linfo(struct bpf_verifier_env *env, env->prev_linfo = linfo; } +static void verbose_invalid_scalar(struct bpf_verifier_env *env, + struct bpf_reg_state *reg, + struct tnum *range, const char *ctx, + const char *reg_name) +{ + char tn_buf[48]; + + verbose(env, "At %s the register %s ", ctx, reg_name); + if (!tnum_is_unknown(reg->var_off)) { + tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off); + verbose(env, "has value %s", tn_buf); + } else { + verbose(env, "has unknown scalar value"); + } + tnum_strn(tn_buf, sizeof(tn_buf), *range); + verbose(env, " should have been in %s\n", tn_buf); +} + static bool type_is_pkt_pointer(enum bpf_reg_type type) { return type == PTR_TO_PACKET || @@ -409,6 +434,7 @@ static bool reg_type_not_null(enum bpf_reg_type type) return type == PTR_TO_SOCKET || type == PTR_TO_TCP_SOCK || type == PTR_TO_MAP_VALUE || + type == PTR_TO_MAP_KEY || type == PTR_TO_SOCK_COMMON; } @@ -451,7 +477,8 @@ static bool arg_type_may_be_null(enum bpf_arg_type type) type == ARG_PTR_TO_MEM_OR_NULL || type == ARG_PTR_TO_CTX_OR_NULL || type == ARG_PTR_TO_SOCKET_OR_NULL || - type == ARG_PTR_TO_ALLOC_MEM_OR_NULL; + type == ARG_PTR_TO_ALLOC_MEM_OR_NULL || + type == ARG_PTR_TO_STACK_OR_NULL; } /* Determine whether the function releases some resources allocated by another @@ -541,6 +568,8 @@ static const char * const reg_type_str[] = { [PTR_TO_RDONLY_BUF_OR_NULL] = "rdonly_buf_or_null", [PTR_TO_RDWR_BUF] = "rdwr_buf", [PTR_TO_RDWR_BUF_OR_NULL] = "rdwr_buf_or_null", + [PTR_TO_FUNC] = "func", + [PTR_TO_MAP_KEY] = "map_key", }; static char slot_type_char[] = { @@ -612,6 +641,7 @@ static void print_verifier_state(struct bpf_verifier_env *env, if (type_is_pkt_pointer(t)) verbose(env, ",r=%d", reg->range); else if (t == CONST_PTR_TO_MAP || + t == PTR_TO_MAP_KEY || t == PTR_TO_MAP_VALUE || t == PTR_TO_MAP_VALUE_OR_NULL) verbose(env, ",ks=%d,vs=%d", @@ -1519,7 +1549,7 @@ static int add_subprog(struct bpf_verifier_env *env, int off) } ret = find_subprog(env, off); if (ret >= 0) - return 0; + return ret; if (env->subprog_cnt >= BPF_MAX_SUBPROGS) { verbose(env, "too many subprograms\n"); return -E2BIG; @@ -1527,7 +1557,7 @@ static int add_subprog(struct bpf_verifier_env *env, int off) env->subprog_info[env->subprog_cnt++].start = off; sort(env->subprog_info, env->subprog_cnt, sizeof(env->subprog_info[0]), cmp_subprogs, NULL); - return 0; + return env->subprog_cnt - 1; } static int check_subprogs(struct bpf_verifier_env *env) @@ -1544,6 +1574,19 @@ static int check_subprogs(struct bpf_verifier_env *env) /* determine subprog starts. The end is one before the next starts */ for (i = 0; i < insn_cnt; i++) { + if (bpf_pseudo_func(insn + i)) { + if (!env->bpf_capable) { + verbose(env, + "function pointers are allowed for CAP_BPF and CAP_SYS_ADMIN\n"); + return -EPERM; + } + ret = add_subprog(env, i + insn[i].imm + 1); + if (ret < 0) + return ret; + /* remember subprog */ + insn[i + 1].imm = ret; + continue; + } if (!bpf_pseudo_call(insn + i)) continue; if (!env->bpf_capable) { @@ -2295,6 +2338,8 @@ static bool is_spillable_regtype(enum bpf_reg_type type) case PTR_TO_PERCPU_BTF_ID: case PTR_TO_MEM: case PTR_TO_MEM_OR_NULL: + case PTR_TO_FUNC: + case PTR_TO_MAP_KEY: return true; default: return false; @@ -2899,6 +2944,10 @@ static int __check_mem_access(struct bpf_verifier_env *env, int regno, reg = &cur_regs(env)[regno]; switch (reg->type) { + case PTR_TO_MAP_KEY: + verbose(env, "invalid access to map key, key_size=%d off=%d size=%d\n", + mem_size, off, size); + break; case PTR_TO_MAP_VALUE: verbose(env, "invalid access to map value, value_size=%d off=%d size=%d\n", mem_size, off, size); @@ -3304,6 +3353,9 @@ static int check_ptr_alignment(struct bpf_verifier_env *env, case PTR_TO_FLOW_KEYS: pointer_desc = "flow keys "; break; + case PTR_TO_MAP_KEY: + pointer_desc = "key "; + break; case PTR_TO_MAP_VALUE: pointer_desc = "value "; break; @@ -3405,7 +3457,7 @@ process_func: continue_func: subprog_end = subprog[idx + 1].start; for (; i < subprog_end; i++) { - if (!bpf_pseudo_call(insn + i)) + if (!bpf_pseudo_call(insn + i) && !bpf_pseudo_func(insn + i)) continue; /* remember insn and function to return to */ ret_insn[frame] = i + 1; @@ -3842,7 +3894,19 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn /* for access checks, reg->off is just part of off */ off += reg->off; - if (reg->type == PTR_TO_MAP_VALUE) { + if (reg->type == PTR_TO_MAP_KEY) { + if (t == BPF_WRITE) { + verbose(env, "write to change key R%d not allowed\n", regno); + return -EACCES; + } + + err = check_mem_region_access(env, regno, off, size, + reg->map_ptr->key_size, false); + if (err) + return err; + if (value_regno >= 0) + mark_reg_unknown(env, regs, value_regno); + } else if (reg->type == PTR_TO_MAP_VALUE) { if (t == BPF_WRITE && value_regno >= 0 && is_pointer_value(env, value_regno)) { verbose(env, "R%d leaks addr into map\n", value_regno); @@ -4258,6 +4322,9 @@ static int check_helper_mem_access(struct bpf_verifier_env *env, int regno, case PTR_TO_PACKET_META: return check_packet_access(env, regno, reg->off, access_size, zero_size_allowed); + case PTR_TO_MAP_KEY: + return check_mem_region_access(env, regno, reg->off, access_size, + reg->map_ptr->key_size, false); case PTR_TO_MAP_VALUE: if (check_map_access_type(env, regno, reg->off, access_size, meta && meta->raw_mode ? BPF_WRITE : @@ -4474,6 +4541,7 @@ static const struct bpf_reg_types map_key_value_types = { PTR_TO_STACK, PTR_TO_PACKET, PTR_TO_PACKET_META, + PTR_TO_MAP_KEY, PTR_TO_MAP_VALUE, }, }; @@ -4505,6 +4573,7 @@ static const struct bpf_reg_types mem_types = { PTR_TO_STACK, PTR_TO_PACKET, PTR_TO_PACKET_META, + PTR_TO_MAP_KEY, PTR_TO_MAP_VALUE, PTR_TO_MEM, PTR_TO_RDONLY_BUF, @@ -4517,6 +4586,7 @@ static const struct bpf_reg_types int_ptr_types = { PTR_TO_STACK, PTR_TO_PACKET, PTR_TO_PACKET_META, + PTR_TO_MAP_KEY, PTR_TO_MAP_VALUE, }, }; @@ -4529,6 +4599,8 @@ static const struct bpf_reg_types const_map_ptr_types = { .types = { CONST_PTR_T static const struct bpf_reg_types btf_ptr_types = { .types = { PTR_TO_BTF_ID } }; static const struct bpf_reg_types spin_lock_types = { .types = { PTR_TO_MAP_VALUE } }; static const struct bpf_reg_types percpu_btf_ptr_types = { .types = { PTR_TO_PERCPU_BTF_ID } }; +static const struct bpf_reg_types func_ptr_types = { .types = { PTR_TO_FUNC } }; +static const struct bpf_reg_types stack_ptr_types = { .types = { PTR_TO_STACK } }; static const struct bpf_reg_types *compatible_reg_types[__BPF_ARG_TYPE_MAX] = { [ARG_PTR_TO_MAP_KEY] = &map_key_value_types, @@ -4557,6 +4629,8 @@ static const struct bpf_reg_types *compatible_reg_types[__BPF_ARG_TYPE_MAX] = { [ARG_PTR_TO_INT] = &int_ptr_types, [ARG_PTR_TO_LONG] = &int_ptr_types, [ARG_PTR_TO_PERCPU_BTF_ID] = &percpu_btf_ptr_types, + [ARG_PTR_TO_FUNC] = &func_ptr_types, + [ARG_PTR_TO_STACK_OR_NULL] = &stack_ptr_types, }; static int check_reg_type(struct bpf_verifier_env *env, u32 regno, @@ -4738,6 +4812,8 @@ skip_type_check: verbose(env, "verifier internal error\n"); return -EFAULT; } + } else if (arg_type == ARG_PTR_TO_FUNC) { + meta->subprogno = reg->subprogno; } else if (arg_type_is_mem_ptr(arg_type)) { /* The access to this pointer is only checked when we hit the * next is_mem_size argument below. @@ -5258,13 +5334,19 @@ static void clear_caller_saved_regs(struct bpf_verifier_env *env, } } -static int check_func_call(struct bpf_verifier_env *env, struct bpf_insn *insn, - int *insn_idx) +typedef int (*set_callee_state_fn)(struct bpf_verifier_env *env, + struct bpf_func_state *caller, + struct bpf_func_state *callee, + int insn_idx); + +static int __check_func_call(struct bpf_verifier_env *env, struct bpf_insn *insn, + int *insn_idx, int subprog, + set_callee_state_fn set_callee_state_cb) { struct bpf_verifier_state *state = env->cur_state; struct bpf_func_info_aux *func_info_aux; struct bpf_func_state *caller, *callee; - int i, err, subprog, target_insn; + int err; bool is_global = false; if (state->curframe + 1 >= MAX_CALL_FRAMES) { @@ -5273,14 +5355,6 @@ static int check_func_call(struct bpf_verifier_env *env, struct bpf_insn *insn, return -E2BIG; } - target_insn = *insn_idx + insn->imm; - subprog = find_subprog(env, target_insn + 1); - if (subprog < 0) { - verbose(env, "verifier bug. No program starts at insn %d\n", - target_insn + 1); - return -EFAULT; - } - caller = state->frame[state->curframe]; if (state->frame[state->curframe + 1]) { verbose(env, "verifier bug. Frame %d already allocated\n", @@ -5335,11 +5409,9 @@ static int check_func_call(struct bpf_verifier_env *env, struct bpf_insn *insn, if (err) return err; - /* copy r1 - r5 args that callee can access. The copy includes parent - * pointers, which connects us up to the liveness chain - */ - for (i = BPF_REG_1; i <= BPF_REG_5; i++) - callee->regs[i] = caller->regs[i]; + err = set_callee_state_cb(env, caller, callee, *insn_idx); + if (err) + return err; clear_caller_saved_regs(env, caller->regs); @@ -5347,7 +5419,7 @@ static int check_func_call(struct bpf_verifier_env *env, struct bpf_insn *insn, state->curframe++; /* and go analyze first insn of the callee */ - *insn_idx = target_insn; + *insn_idx = env->subprog_info[subprog].start - 1; if (env->log.level & BPF_LOG_LEVEL) { verbose(env, "caller:\n"); @@ -5358,6 +5430,92 @@ static int check_func_call(struct bpf_verifier_env *env, struct bpf_insn *insn, return 0; } +int map_set_for_each_callback_args(struct bpf_verifier_env *env, + struct bpf_func_state *caller, + struct bpf_func_state *callee) +{ + /* bpf_for_each_map_elem(struct bpf_map *map, void *callback_fn, + * void *callback_ctx, u64 flags); + * callback_fn(struct bpf_map *map, void *key, void *value, + * void *callback_ctx); + */ + callee->regs[BPF_REG_1] = caller->regs[BPF_REG_1]; + + callee->regs[BPF_REG_2].type = PTR_TO_MAP_KEY; + __mark_reg_known_zero(&callee->regs[BPF_REG_2]); + callee->regs[BPF_REG_2].map_ptr = caller->regs[BPF_REG_1].map_ptr; + + callee->regs[BPF_REG_3].type = PTR_TO_MAP_VALUE; + __mark_reg_known_zero(&callee->regs[BPF_REG_3]); + callee->regs[BPF_REG_3].map_ptr = caller->regs[BPF_REG_1].map_ptr; + + /* pointer to stack or null */ + callee->regs[BPF_REG_4] = caller->regs[BPF_REG_3]; + + /* unused */ + __mark_reg_not_init(env, &callee->regs[BPF_REG_5]); + return 0; +} + +static int set_callee_state(struct bpf_verifier_env *env, + struct bpf_func_state *caller, + struct bpf_func_state *callee, int insn_idx) +{ + int i; + + /* copy r1 - r5 args that callee can access. The copy includes parent + * pointers, which connects us up to the liveness chain + */ + for (i = BPF_REG_1; i <= BPF_REG_5; i++) + callee->regs[i] = caller->regs[i]; + return 0; +} + +static int check_func_call(struct bpf_verifier_env *env, struct bpf_insn *insn, + int *insn_idx) +{ + int subprog, target_insn; + + target_insn = *insn_idx + insn->imm + 1; + subprog = find_subprog(env, target_insn); + if (subprog < 0) { + verbose(env, "verifier bug. No program starts at insn %d\n", + target_insn); + return -EFAULT; + } + + return __check_func_call(env, insn, insn_idx, subprog, set_callee_state); +} + +static int set_map_elem_callback_state(struct bpf_verifier_env *env, + struct bpf_func_state *caller, + struct bpf_func_state *callee, + int insn_idx) +{ + struct bpf_insn_aux_data *insn_aux = &env->insn_aux_data[insn_idx]; + struct bpf_map *map; + int err; + + if (bpf_map_ptr_poisoned(insn_aux)) { + verbose(env, "tail_call abusing map_ptr\n"); + return -EINVAL; + } + + map = BPF_MAP_PTR(insn_aux->map_ptr_state); + if (!map->ops->map_set_for_each_callback_args || + !map->ops->map_for_each_callback) { + verbose(env, "callback function not allowed for map\n"); + return -ENOTSUPP; + } + + err = map->ops->map_set_for_each_callback_args(env, caller, callee); + if (err) + return err; + + callee->in_callback_fn = true; + return 0; +} + static int prepare_func_exit(struct bpf_verifier_env *env, int *insn_idx) { struct bpf_verifier_state *state = env->cur_state; @@ -5380,8 +5538,22 @@ static int prepare_func_exit(struct bpf_verifier_env *env, int *insn_idx) state->curframe--; caller = state->frame[state->curframe]; - /* return to the caller whatever r0 had in the callee */ - caller->regs[BPF_REG_0] = *r0; + if (callee->in_callback_fn) { + /* enforce R0 return value range [0, 1]. */ + struct tnum range = tnum_range(0, 1); + + if (r0->type != SCALAR_VALUE) { + verbose(env, "R0 not a scalar value\n"); + return -EACCES; + } + if (!tnum_in(range, r0->var_off)) { + verbose_invalid_scalar(env, r0, &range, "callback return", "R0"); + return -EINVAL; + } + } else { + /* return to the caller whatever r0 had in the callee */ + caller->regs[BPF_REG_0] = *r0; + } /* Transfer references to the caller */ err = transfer_reference_state(caller, callee); @@ -5436,7 +5608,9 @@ record_func_map(struct bpf_verifier_env *env, struct bpf_call_arg_meta *meta, func_id != BPF_FUNC_map_delete_elem && func_id != BPF_FUNC_map_push_elem && func_id != BPF_FUNC_map_pop_elem && - func_id != BPF_FUNC_map_peek_elem) + func_id != BPF_FUNC_map_peek_elem && + func_id != BPF_FUNC_for_each_map_elem && + func_id != BPF_FUNC_redirect_map) return 0; if (map == NULL) { @@ -5517,15 +5691,18 @@ static int check_reference_leak(struct bpf_verifier_env *env) return state->acquired_refs ? -EINVAL : 0; } -static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn_idx) +static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn, + int *insn_idx_p) { const struct bpf_func_proto *fn = NULL; struct bpf_reg_state *regs; struct bpf_call_arg_meta meta; + int insn_idx = *insn_idx_p; bool changes_data; - int i, err; + int i, err, func_id; /* find function prototype */ + func_id = insn->imm; if (func_id < 0 || func_id >= __BPF_FUNC_MAX_ID) { verbose(env, "invalid func %s#%d\n", func_id_name(func_id), func_id); @@ -5571,7 +5748,7 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn meta.func_id = func_id; /* check args */ - for (i = 0; i < 5; i++) { + for (i = 0; i < MAX_BPF_FUNC_REG_ARGS; i++) { err = check_func_arg(env, i, &meta, fn); if (err) return err; @@ -5621,6 +5798,13 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn return -EINVAL; } + if (func_id == BPF_FUNC_for_each_map_elem) { + err = __check_func_call(env, insn, insn_idx_p, meta.subprogno, + set_map_elem_callback_state); + if (err < 0) + return -EINVAL; + } + /* reset caller saved regs */ for (i = 0; i < CALLER_SAVED_REGS; i++) { mark_reg_not_init(env, regs, caller_saved[i]); @@ -5878,6 +6062,19 @@ static int retrieve_ptr_limit(const struct bpf_reg_state *ptr_reg, else *ptr_limit = -off - 1; return *ptr_limit >= max ? -ERANGE : 0; + case PTR_TO_MAP_KEY: + /* Currently, this code is not exercised as the only use + * is bpf_for_each_map_elem() helper which requires + * bpf_capble. The code has been tested manually for + * future use. + */ + if (mask_to_left) { + *ptr_limit = ptr_reg->umax_value + ptr_reg->off; + } else { + off = ptr_reg->smin_value + ptr_reg->off; + *ptr_limit = ptr_reg->map_ptr->key_size - off; + } + return 0; case PTR_TO_MAP_VALUE: max = ptr_reg->map_ptr->value_size; if (mask_to_left) { @@ -5909,7 +6106,7 @@ static int update_alu_sanitation_state(struct bpf_insn_aux_data *aux, aux->alu_limit != alu_limit)) return -EACCES; - /* Corresponding fixup done in fixup_bpf_calls(). */ + /* Corresponding fixup done in do_misc_fixups(). */ aux->alu_state = alu_state; aux->alu_limit = alu_limit; return 0; @@ -6084,6 +6281,7 @@ static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env, verbose(env, "R%d pointer arithmetic on %s prohibited\n", dst, reg_type_str[ptr_reg->type]); return -EACCES; + case PTR_TO_MAP_KEY: case PTR_TO_MAP_VALUE: if (!env->allow_ptr_leaks && !known && (smin_val < 0) != (smax_val < 0)) { verbose(env, "R%d has unknown scalar with mixed signed bounds, pointer arithmetic with it prohibited for !root\n", @@ -8263,6 +8461,24 @@ static int check_ld_imm(struct bpf_verifier_env *env, struct bpf_insn *insn) return 0; } + if (insn->src_reg == BPF_PSEUDO_FUNC) { + struct bpf_prog_aux *aux = env->prog->aux; + u32 subprogno = insn[1].imm; + + if (!aux->func_info) { + verbose(env, "missing btf func_info\n"); + return -EINVAL; + } + if (aux->func_info_aux[subprogno].linkage != BTF_FUNC_STATIC) { + verbose(env, "callback function not static\n"); + return -EINVAL; + } + + dst_reg->type = PTR_TO_FUNC; + dst_reg->subprogno = subprogno; + return 0; + } + map = env->used_maps[aux->map_index]; mark_reg_known_zero(env, regs, insn->dst_reg); dst_reg->map_ptr = map; @@ -8491,17 +8707,7 @@ static int check_return_code(struct bpf_verifier_env *env) } if (!tnum_in(range, reg->var_off)) { - char tn_buf[48]; - - verbose(env, "At program exit the register R0 "); - if (!tnum_is_unknown(reg->var_off)) { - tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off); - verbose(env, "has value %s", tn_buf); - } else { - verbose(env, "has unknown scalar value"); - } - tnum_strn(tn_buf, sizeof(tn_buf), range); - verbose(env, " should have been in %s\n", tn_buf); + verbose_invalid_scalar(env, reg, &range, "program exit", "R0"); return -EINVAL; } @@ -8628,6 +8834,27 @@ static int push_insn(int t, int w, int e, struct bpf_verifier_env *env, return DONE_EXPLORING; } +static int visit_func_call_insn(int t, int insn_cnt, + struct bpf_insn *insns, + struct bpf_verifier_env *env, + bool visit_callee) +{ + int ret; + + ret = push_insn(t, t + 1, FALLTHROUGH, env, false); + if (ret) + return ret; + + if (t + 1 < insn_cnt) + init_explored_state(env, t + 1); + if (visit_callee) { + init_explored_state(env, t); + ret = push_insn(t, t + insns[t].imm + 1, BRANCH, + env, false); + } + return ret; +} + /* Visits the instruction at index t and returns one of the following: * < 0 - an error occurred * DONE_EXPLORING - the instruction was fully explored @@ -8638,6 +8865,9 @@ static int visit_insn(int t, int insn_cnt, struct bpf_verifier_env *env) struct bpf_insn *insns = env->prog->insnsi; int ret; + if (bpf_pseudo_func(insns + t)) + return visit_func_call_insn(t, insn_cnt, insns, env, true); + /* All non-branch instructions have a single fall-through edge. */ if (BPF_CLASS(insns[t].code) != BPF_JMP && BPF_CLASS(insns[t].code) != BPF_JMP32) @@ -8648,18 +8878,8 @@ static int visit_insn(int t, int insn_cnt, struct bpf_verifier_env *env) return DONE_EXPLORING; case BPF_CALL: - ret = push_insn(t, t + 1, FALLTHROUGH, env, false); - if (ret) - return ret; - - if (t + 1 < insn_cnt) - init_explored_state(env, t + 1); - if (insns[t].src_reg == BPF_PSEUDO_CALL) { - init_explored_state(env, t); - ret = push_insn(t, t + insns[t].imm + 1, BRANCH, - env, false); - } - return ret; + return visit_func_call_insn(t, insn_cnt, insns, env, + insns[t].src_reg == BPF_PSEUDO_CALL); case BPF_JA: if (BPF_SRC(insns[t].code) != BPF_K) @@ -9272,6 +9492,7 @@ static bool regsafe(struct bpf_reg_state *rold, struct bpf_reg_state *rcur, */ return false; } + case PTR_TO_MAP_KEY: case PTR_TO_MAP_VALUE: /* If the new min/max/var_off satisfy the old ones and * everything else matches, we are OK. @@ -10118,10 +10339,9 @@ static int do_check(struct bpf_verifier_env *env) if (insn->src_reg == BPF_PSEUDO_CALL) err = check_func_call(env, insn, &env->insn_idx); else - err = check_helper_call(env, insn->imm, env->insn_idx); + err = check_helper_call(env, insn, &env->insn_idx); if (err) return err; - } else if (opcode == BPF_JA) { if (BPF_SRC(insn->code) != BPF_K || insn->imm != 0 || @@ -10550,6 +10770,12 @@ static int resolve_pseudo_ldimm64(struct bpf_verifier_env *env) goto next_insn; } + if (insn[0].src_reg == BPF_PSEUDO_FUNC) { + aux = &env->insn_aux_data[i]; + aux->ptr_type = PTR_TO_FUNC; + goto next_insn; + } + /* In final convert_pseudo_ld_imm64() step, this is * converted into regular 64-bit imm load insn. */ @@ -10682,9 +10908,13 @@ static void convert_pseudo_ld_imm64(struct bpf_verifier_env *env) int insn_cnt = env->prog->len; int i; - for (i = 0; i < insn_cnt; i++, insn++) - if (insn->code == (BPF_LD | BPF_IMM | BPF_DW)) - insn->src_reg = 0; + for (i = 0; i < insn_cnt; i++, insn++) { + if (insn->code != (BPF_LD | BPF_IMM | BPF_DW)) + continue; + if (insn->src_reg == BPF_PSEUDO_FUNC) + continue; + insn->src_reg = 0; + } } /* single env->prog->insni[off] instruction was replaced with the range @@ -11323,6 +11553,12 @@ static int jit_subprogs(struct bpf_verifier_env *env) return 0; for (i = 0, insn = prog->insnsi; i < prog->len; i++, insn++) { + if (bpf_pseudo_func(insn)) { + env->insn_aux_data[i].call_imm = insn->imm; + /* subprog is encoded in insn[1].imm */ + continue; + } + if (!bpf_pseudo_call(insn)) continue; /* Upon error here we cannot fall back to interpreter but @@ -11452,6 +11688,12 @@ static int jit_subprogs(struct bpf_verifier_env *env) for (i = 0; i < env->subprog_cnt; i++) { insn = func[i]->insnsi; for (j = 0; j < func[i]->len; j++, insn++) { + if (bpf_pseudo_func(insn)) { + subprog = insn[1].imm; + insn[0].imm = (u32)(long)func[subprog]->bpf_func; + insn[1].imm = ((u64)(long)func[subprog]->bpf_func) >> 32; + continue; + } if (!bpf_pseudo_call(insn)) continue; subprog = insn->off; @@ -11497,6 +11739,11 @@ static int jit_subprogs(struct bpf_verifier_env *env) * later look the same as if they were interpreted only. */ for (i = 0, insn = prog->insnsi; i < prog->len; i++, insn++) { + if (bpf_pseudo_func(insn)) { + insn[0].imm = env->insn_aux_data[i].call_imm; + insn[1].imm = find_subprog(env, i + insn[0].imm + 1); + continue; + } if (!bpf_pseudo_call(insn)) continue; insn->off = env->insn_aux_data[i].call_imm; @@ -11561,6 +11808,14 @@ static int fixup_call_args(struct bpf_verifier_env *env) return -EINVAL; } for (i = 0; i < prog->len; i++, insn++) { + if (bpf_pseudo_func(insn)) { + /* When JIT fails the progs with callback calls + * have to be rejected, since interpreter doesn't support them yet. + */ + verbose(env, "callbacks are not allowed in non-JITed programs\n"); + return -EINVAL; + } + if (!bpf_pseudo_call(insn)) continue; depth = get_callee_stack_depth(env, insn, i); @@ -11573,12 +11828,10 @@ static int fixup_call_args(struct bpf_verifier_env *env) return err; } -/* fixup insn->imm field of bpf_call instructions - * and inline eligible helpers as explicit sequence of BPF instructions - * - * this function is called after eBPF program passed verification +/* Do various post-verification rewrites in a single program pass. + * These rewrites simplify JIT and interpreter implementations. */ -static int fixup_bpf_calls(struct bpf_verifier_env *env) +static int do_misc_fixups(struct bpf_verifier_env *env) { struct bpf_prog *prog = env->prog; bool expect_blinding = bpf_jit_blinding_enabled(prog); @@ -11593,6 +11846,7 @@ static int fixup_bpf_calls(struct bpf_verifier_env *env) int i, ret, cnt, delta = 0; for (i = 0; i < insn_cnt; i++, insn++) { + /* Make divide-by-zero exceptions impossible. */ if (insn->code == (BPF_ALU64 | BPF_MOD | BPF_X) || insn->code == (BPF_ALU64 | BPF_DIV | BPF_X) || insn->code == (BPF_ALU | BPF_MOD | BPF_X) || @@ -11633,6 +11887,7 @@ static int fixup_bpf_calls(struct bpf_verifier_env *env) continue; } + /* Implement LD_ABS and LD_IND with a rewrite, if supported by the program type. */ if (BPF_CLASS(insn->code) == BPF_LD && (BPF_MODE(insn->code) == BPF_ABS || BPF_MODE(insn->code) == BPF_IND)) { @@ -11652,6 +11907,7 @@ static int fixup_bpf_calls(struct bpf_verifier_env *env) continue; } + /* Rewrite pointer arithmetic to mitigate speculation attacks. */ if (insn->code == (BPF_ALU64 | BPF_ADD | BPF_X) || insn->code == (BPF_ALU64 | BPF_SUB | BPF_X)) { const u8 code_add = BPF_ALU64 | BPF_ADD | BPF_X; @@ -11800,7 +12056,8 @@ static int fixup_bpf_calls(struct bpf_verifier_env *env) insn->imm == BPF_FUNC_map_delete_elem || insn->imm == BPF_FUNC_map_push_elem || insn->imm == BPF_FUNC_map_pop_elem || - insn->imm == BPF_FUNC_map_peek_elem)) { + insn->imm == BPF_FUNC_map_peek_elem || + insn->imm == BPF_FUNC_redirect_map)) { aux = &env->insn_aux_data[i + delta]; if (bpf_map_ptr_poisoned(aux)) goto patch_call_imm; @@ -11842,6 +12099,9 @@ static int fixup_bpf_calls(struct bpf_verifier_env *env) (int (*)(struct bpf_map *map, void *value))NULL)); BUILD_BUG_ON(!__same_type(ops->map_peek_elem, (int (*)(struct bpf_map *map, void *value))NULL)); + BUILD_BUG_ON(!__same_type(ops->map_redirect, + (int (*)(struct bpf_map *map, u32 ifindex, u64 flags))NULL)); + patch_map_ops_generic: switch (insn->imm) { case BPF_FUNC_map_lookup_elem: @@ -11868,11 +12128,16 @@ patch_map_ops_generic: insn->imm = BPF_CAST_CALL(ops->map_peek_elem) - __bpf_call_base; continue; + case BPF_FUNC_redirect_map: + insn->imm = BPF_CAST_CALL(ops->map_redirect) - + __bpf_call_base; + continue; } goto patch_call_imm; } + /* Implement bpf_jiffies64 inline. */ if (prog->jit_requested && BITS_PER_LONG == 64 && insn->imm == BPF_FUNC_jiffies64) { struct bpf_insn ld_jiffies_addr[2] = { @@ -12683,7 +12948,7 @@ skip_full_check: ret = convert_ctx_accesses(env); if (ret == 0) - ret = fixup_bpf_calls(env); + ret = do_misc_fixups(env); /* do 32-bit optimization after insn patching has done so those patched * insns could be handled correctly. |