diff options
Diffstat (limited to 'tools/lib/bpf/libbpf.c')
| -rw-r--r-- | tools/lib/bpf/libbpf.c | 110 |
1 files changed, 91 insertions, 19 deletions
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 49cd304ae3bc..1cbacf9e71f3 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -130,6 +130,7 @@ static const char * const link_type_name[] = { [BPF_LINK_TYPE_PERF_EVENT] = "perf_event", [BPF_LINK_TYPE_KPROBE_MULTI] = "kprobe_multi", [BPF_LINK_TYPE_STRUCT_OPS] = "struct_ops", + [BPF_LINK_TYPE_NETFILTER] = "netfilter", }; static const char * const map_type_name[] = { @@ -201,6 +202,7 @@ static const char * const prog_type_name[] = { [BPF_PROG_TYPE_LSM] = "lsm", [BPF_PROG_TYPE_SK_LOOKUP] = "sk_lookup", [BPF_PROG_TYPE_SYSCALL] = "syscall", + [BPF_PROG_TYPE_NETFILTER] = "netfilter", }; static int __base_pr(enum libbpf_print_level level, const char *format, @@ -333,6 +335,7 @@ struct reloc_desc { struct { int map_idx; int sym_off; + int ext_idx; }; }; }; @@ -4042,7 +4045,7 @@ static int bpf_program__record_reloc(struct bpf_program *prog, else reloc_desc->type = RELO_EXTERN_LD64; reloc_desc->insn_idx = insn_idx; - reloc_desc->sym_off = i; /* sym_off stores extern index */ + reloc_desc->ext_idx = i; return 0; } @@ -5811,8 +5814,8 @@ out: } /* base map load ldimm64 special constant, used also for log fixup logic */ -#define MAP_LDIMM64_POISON_BASE 2001000000 -#define MAP_LDIMM64_POISON_PFX "200100" +#define POISON_LDIMM64_MAP_BASE 2001000000 +#define POISON_LDIMM64_MAP_PFX "200100" static void poison_map_ldimm64(struct bpf_program *prog, int relo_idx, int insn_idx, struct bpf_insn *insn, @@ -5834,12 +5837,36 @@ static void poison_map_ldimm64(struct bpf_program *prog, int relo_idx, * invalid func unknown#2001000123 * where lower 123 is map index into obj->maps[] array */ - insn->imm = MAP_LDIMM64_POISON_BASE + map_idx; + insn->imm = POISON_LDIMM64_MAP_BASE + map_idx; insn++; } } +/* unresolved kfunc call special constant, used also for log fixup logic */ +#define POISON_CALL_KFUNC_BASE 2002000000 +#define POISON_CALL_KFUNC_PFX "2002" + +static void poison_kfunc_call(struct bpf_program *prog, int relo_idx, + int insn_idx, struct bpf_insn *insn, + int ext_idx, const struct extern_desc *ext) +{ + pr_debug("prog '%s': relo #%d: poisoning insn #%d that calls kfunc '%s'\n", + prog->name, relo_idx, insn_idx, ext->name); + + /* we turn kfunc call into invalid helper call with identifiable constant */ + insn->code = BPF_JMP | BPF_CALL; + insn->dst_reg = 0; + insn->src_reg = 0; + insn->off = 0; + /* if this instruction is reachable (not a dead code), + * verifier will complain with something like: + * invalid func unknown#2001000123 + * where lower 123 is extern index into obj->externs[] array + */ + insn->imm = POISON_CALL_KFUNC_BASE + ext_idx; +} + /* Relocate data references within program code: * - map references; * - global variable references; @@ -5885,7 +5912,7 @@ bpf_object__relocate_data(struct bpf_object *obj, struct bpf_program *prog) } break; case RELO_EXTERN_LD64: - ext = &obj->externs[relo->sym_off]; + ext = &obj->externs[relo->ext_idx]; if (ext->type == EXT_KCFG) { if (obj->gen_loader) { insn[0].src_reg = BPF_PSEUDO_MAP_IDX_VALUE; @@ -5907,14 +5934,14 @@ bpf_object__relocate_data(struct bpf_object *obj, struct bpf_program *prog) } break; case RELO_EXTERN_CALL: - ext = &obj->externs[relo->sym_off]; + ext = &obj->externs[relo->ext_idx]; insn[0].src_reg = BPF_PSEUDO_KFUNC_CALL; if (ext->is_set) { insn[0].imm = ext->ksym.kernel_btf_id; insn[0].off = ext->ksym.btf_fd_idx; - } else { /* unresolved weak kfunc */ - insn[0].imm = 0; - insn[0].off = 0; + } else { /* unresolved weak kfunc call */ + poison_kfunc_call(prog, i, relo->insn_idx, insn, + relo->ext_idx, ext); } break; case RELO_SUBPROG_ADDR: @@ -7022,13 +7049,13 @@ static void fixup_log_missing_map_load(struct bpf_program *prog, char *buf, size_t buf_sz, size_t log_sz, char *line1, char *line2, char *line3) { - /* Expected log for failed and not properly guarded CO-RE relocation: + /* Expected log for failed and not properly guarded map reference: * line1 -> 123: (85) call unknown#2001000345 * line2 -> invalid func unknown#2001000345 * line3 -> <anything else or end of buffer> * * "123" is the index of the instruction that was poisoned. - * "345" in "2001000345" are map index in obj->maps to fetch map name. + * "345" in "2001000345" is a map index in obj->maps to fetch map name. */ struct bpf_object *obj = prog->obj; const struct bpf_map *map; @@ -7038,7 +7065,7 @@ static void fixup_log_missing_map_load(struct bpf_program *prog, if (sscanf(line1, "%d: (%*d) call unknown#%d\n", &insn_idx, &map_idx) != 2) return; - map_idx -= MAP_LDIMM64_POISON_BASE; + map_idx -= POISON_LDIMM64_MAP_BASE; if (map_idx < 0 || map_idx >= obj->nr_maps) return; map = &obj->maps[map_idx]; @@ -7051,6 +7078,39 @@ static void fixup_log_missing_map_load(struct bpf_program *prog, patch_log(buf, buf_sz, log_sz, line1, line3 - line1, patch); } +static void fixup_log_missing_kfunc_call(struct bpf_program *prog, + char *buf, size_t buf_sz, size_t log_sz, + char *line1, char *line2, char *line3) +{ + /* Expected log for failed and not properly guarded kfunc call: + * line1 -> 123: (85) call unknown#2002000345 + * line2 -> invalid func unknown#2002000345 + * line3 -> <anything else or end of buffer> + * + * "123" is the index of the instruction that was poisoned. + * "345" in "2002000345" is an extern index in obj->externs to fetch kfunc name. + */ + struct bpf_object *obj = prog->obj; + const struct extern_desc *ext; + int insn_idx, ext_idx; + char patch[128]; + + if (sscanf(line1, "%d: (%*d) call unknown#%d\n", &insn_idx, &ext_idx) != 2) + return; + + ext_idx -= POISON_CALL_KFUNC_BASE; + if (ext_idx < 0 || ext_idx >= obj->nr_extern) + return; + ext = &obj->externs[ext_idx]; + + snprintf(patch, sizeof(patch), + "%d: <invalid kfunc call>\n" + "kfunc '%s' is referenced but wasn't resolved\n", + insn_idx, ext->name); + + patch_log(buf, buf_sz, log_sz, line1, line3 - line1, patch); +} + static void fixup_verifier_log(struct bpf_program *prog, char *buf, size_t buf_sz) { /* look for familiar error patterns in last N lines of the log */ @@ -7070,23 +7130,33 @@ static void fixup_verifier_log(struct bpf_program *prog, char *buf, size_t buf_s if (!cur_line) return; - /* failed CO-RE relocation case */ if (str_has_pfx(cur_line, "invalid func unknown#195896080\n")) { prev_line = find_prev_line(buf, cur_line); if (!prev_line) continue; + /* failed CO-RE relocation case */ fixup_log_failed_core_relo(prog, buf, buf_sz, log_sz, prev_line, cur_line, next_line); return; - } else if (str_has_pfx(cur_line, "invalid func unknown#"MAP_LDIMM64_POISON_PFX)) { + } else if (str_has_pfx(cur_line, "invalid func unknown#"POISON_LDIMM64_MAP_PFX)) { prev_line = find_prev_line(buf, cur_line); if (!prev_line) continue; + /* reference to uncreated BPF map */ fixup_log_missing_map_load(prog, buf, buf_sz, log_sz, prev_line, cur_line, next_line); return; + } else if (str_has_pfx(cur_line, "invalid func unknown#"POISON_CALL_KFUNC_PFX)) { + prev_line = find_prev_line(buf, cur_line); + if (!prev_line) + continue; + + /* reference to unresolved kfunc */ + fixup_log_missing_kfunc_call(prog, buf, buf_sz, log_sz, + prev_line, cur_line, next_line); + return; } } } @@ -7098,7 +7168,7 @@ static int bpf_program_record_relos(struct bpf_program *prog) for (i = 0; i < prog->nr_reloc; i++) { struct reloc_desc *relo = &prog->reloc_desc[i]; - struct extern_desc *ext = &obj->externs[relo->sym_off]; + struct extern_desc *ext = &obj->externs[relo->ext_idx]; int kind; switch (relo->type) { @@ -7536,8 +7606,9 @@ static int bpf_object__resolve_ksym_func_btf_id(struct bpf_object *obj, ret = bpf_core_types_are_compat(obj->btf, local_func_proto_id, kern_btf, kfunc_proto_id); if (ret <= 0) { - pr_warn("extern (func ksym) '%s': func_proto [%d] incompatible with kernel [%d]\n", - ext->name, local_func_proto_id, kfunc_proto_id); + pr_warn("extern (func ksym) '%s': func_proto [%d] incompatible with %s [%d]\n", + ext->name, local_func_proto_id, + mod_btf ? mod_btf->name : "vmlinux", kfunc_proto_id); return -EINVAL; } @@ -7571,8 +7642,8 @@ static int bpf_object__resolve_ksym_func_btf_id(struct bpf_object *obj, * {kernel_btf_id, kernel_btf_obj_fd} -> fixup ld_imm64. */ ext->ksym.kernel_btf_obj_fd = mod_btf ? mod_btf->fd : 0; - pr_debug("extern (func ksym) '%s': resolved to kernel [%d]\n", - ext->name, kfunc_id); + pr_debug("extern (func ksym) '%s': resolved to %s [%d]\n", + ext->name, mod_btf ? mod_btf->name : "vmlinux", kfunc_id); return 0; } @@ -8641,6 +8712,7 @@ static const struct bpf_sec_def section_defs[] = { SEC_DEF("struct_ops+", STRUCT_OPS, 0, SEC_NONE), SEC_DEF("struct_ops.s+", STRUCT_OPS, 0, SEC_SLEEPABLE), SEC_DEF("sk_lookup", SK_LOOKUP, BPF_SK_LOOKUP, SEC_ATTACHABLE), + SEC_DEF("netfilter", NETFILTER, 0, SEC_NONE), }; static size_t custom_sec_def_cnt; |