diff options
| -rw-r--r-- | include/linux/filter.h | 9 | ||||
| -rw-r--r-- | kernel/bpf/core.c | 4 | ||||
| -rw-r--r-- | kernel/bpf/disasm.c | 65 | ||||
| -rw-r--r-- | kernel/bpf/disasm.h | 29 | ||||
| -rw-r--r-- | kernel/bpf/syscall.c | 87 | ||||
| -rw-r--r-- | kernel/bpf/verifier.c | 30 | ||||
| -rw-r--r-- | tools/bpf/bpftool/prog.c | 181 |
7 files changed, 370 insertions, 35 deletions
diff --git a/include/linux/filter.h b/include/linux/filter.h index e872b4ebaa575..2b0df27036711 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -18,6 +18,7 @@ #include <linux/capability.h> #include <linux/cryptohash.h> #include <linux/set_memory.h> +#include <linux/kallsyms.h> #include <net/sch_generic.h> @@ -724,6 +725,14 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog); void bpf_jit_compile(struct bpf_prog *prog); bool bpf_helper_changes_pkt_data(void *func); +static inline bool bpf_dump_raw_ok(void) +{ + /* Reconstruction of call-sites is dependent on kallsyms, + * thus make dump the same restriction. + */ + return kallsyms_show_value() == 1; +} + struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off, const struct bpf_insn *patch, u32 len); diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 768e0a02d8c8a..70a534549cd3e 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -771,7 +771,9 @@ struct bpf_prog *bpf_jit_blind_constants(struct bpf_prog *prog) /* Base function for offset calculation. Needs to go into .text section, * therefore keeping it non-static as well; will also be used by JITs - * anyway later on, so do not let the compiler omit it. + * anyway later on, so do not let the compiler omit it. This also needs + * to go into kallsyms for correlation from e.g. bpftool, so naming + * must not change. */ noinline u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) { diff --git a/kernel/bpf/disasm.c b/kernel/bpf/disasm.c index 883f88fa5bfc6..8740406df2cd7 100644 --- a/kernel/bpf/disasm.c +++ b/kernel/bpf/disasm.c @@ -21,10 +21,39 @@ static const char * const func_id_str[] = { }; #undef __BPF_FUNC_STR_FN -const char *func_id_name(int id) +static const char *__func_get_name(const struct bpf_insn_cbs *cbs, + const struct bpf_insn *insn, + char *buff, size_t len) { BUILD_BUG_ON(ARRAY_SIZE(func_id_str) != __BPF_FUNC_MAX_ID); + if (insn->src_reg != BPF_PSEUDO_CALL && + insn->imm >= 0 && insn->imm < __BPF_FUNC_MAX_ID && + func_id_str[insn->imm]) + return func_id_str[insn->imm]; + + if (cbs && cbs->cb_call) + return cbs->cb_call(cbs->private_data, insn); + + if (insn->src_reg == BPF_PSEUDO_CALL) + snprintf(buff, len, "%+d", insn->imm); + + return buff; +} + +static const char *__func_imm_name(const struct bpf_insn_cbs *cbs, + const struct bpf_insn *insn, + u64 full_imm, char *buff, size_t len) +{ + if (cbs && cbs->cb_imm) + return cbs->cb_imm(cbs->private_data, insn, full_imm); + + snprintf(buff, len, "0x%llx", (unsigned long long)full_imm); + return buff; +} + +const char *func_id_name(int id) +{ if (id >= 0 && id < __BPF_FUNC_MAX_ID && func_id_str[id]) return func_id_str[id]; else @@ -83,7 +112,7 @@ static const char *const bpf_jmp_string[16] = { [BPF_EXIT >> 4] = "exit", }; -static void print_bpf_end_insn(bpf_insn_print_cb verbose, +static void print_bpf_end_insn(bpf_insn_print_t verbose, struct bpf_verifier_env *env, const struct bpf_insn *insn) { @@ -92,9 +121,12 @@ static void print_bpf_end_insn(bpf_insn_print_cb verbose, insn->imm, insn->dst_reg); } -void print_bpf_insn(bpf_insn_print_cb verbose, struct bpf_verifier_env *env, - const struct bpf_insn *insn, bool allow_ptr_leaks) +void print_bpf_insn(const struct bpf_insn_cbs *cbs, + struct bpf_verifier_env *env, + const struct bpf_insn *insn, + bool allow_ptr_leaks) { + const bpf_insn_print_t verbose = cbs->cb_print; u8 class = BPF_CLASS(insn->code); if (class == BPF_ALU || class == BPF_ALU64) { @@ -175,12 +207,15 @@ void print_bpf_insn(bpf_insn_print_cb verbose, struct bpf_verifier_env *env, */ u64 imm = ((u64)(insn + 1)->imm << 32) | (u32)insn->imm; bool map_ptr = insn->src_reg == BPF_PSEUDO_MAP_FD; + char tmp[64]; if (map_ptr && !allow_ptr_leaks) imm = 0; - verbose(env, "(%02x) r%d = 0x%llx\n", insn->code, - insn->dst_reg, (unsigned long long)imm); + verbose(env, "(%02x) r%d = %s\n", + insn->code, insn->dst_reg, + __func_imm_name(cbs, insn, imm, + tmp, sizeof(tmp))); } else { verbose(env, "BUG_ld_%02x\n", insn->code); return; @@ -189,12 +224,20 @@ void print_bpf_insn(bpf_insn_print_cb verbose, struct bpf_verifier_env *env, u8 opcode = BPF_OP(insn->code); if (opcode == BPF_CALL) { - if (insn->src_reg == BPF_PSEUDO_CALL) - verbose(env, "(%02x) call pc%+d\n", insn->code, - insn->imm); - else + char tmp[64]; + + if (insn->src_reg == BPF_PSEUDO_CALL) { + verbose(env, "(%02x) call pc%s\n", + insn->code, + __func_get_name(cbs, insn, + tmp, sizeof(tmp))); + } else { + strcpy(tmp, "unknown"); verbose(env, "(%02x) call %s#%d\n", insn->code, - func_id_name(insn->imm), insn->imm); + __func_get_name(cbs, insn, + tmp, sizeof(tmp)), + insn->imm); + } } else if (insn->code == (BPF_JMP | BPF_JA)) { verbose(env, "(%02x) goto pc%+d\n", insn->code, insn->off); diff --git a/kernel/bpf/disasm.h b/kernel/bpf/disasm.h index 8de977e420b64..e0857d016f895 100644 --- a/kernel/bpf/disasm.h +++ b/kernel/bpf/disasm.h @@ -17,16 +17,35 @@ #include <linux/bpf.h> #include <linux/kernel.h> #include <linux/stringify.h> +#ifndef __KERNEL__ +#include <stdio.h> +#include <string.h> +#endif + +struct bpf_verifier_env; extern const char *const bpf_alu_string[16]; extern const char *const bpf_class_string[8]; const char *func_id_name(int id); -struct bpf_verifier_env; -typedef void (*bpf_insn_print_cb)(struct bpf_verifier_env *env, - const char *, ...); -void print_bpf_insn(bpf_insn_print_cb verbose, struct bpf_verifier_env *env, - const struct bpf_insn *insn, bool allow_ptr_leaks); +typedef void (*bpf_insn_print_t)(struct bpf_verifier_env *env, + const char *, ...); +typedef const char *(*bpf_insn_revmap_call_t)(void *private_data, + const struct bpf_insn *insn); +typedef const char *(*bpf_insn_print_imm_t)(void *private_data, + const struct bpf_insn *insn, + __u64 full_imm); + +struct bpf_insn_cbs { + bpf_insn_print_t cb_print; + bpf_insn_revmap_call_t cb_call; + bpf_insn_print_imm_t cb_imm; + void *private_data; +}; +void print_bpf_insn(const struct bpf_insn_cbs *cbs, + struct bpf_verifier_env *env, + const struct bpf_insn *insn, + bool allow_ptr_leaks); #endif diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 30e728dcd35d6..007802c5ca7d7 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -1558,6 +1558,67 @@ static int bpf_map_get_fd_by_id(const union bpf_attr *attr) return fd; } +static const struct bpf_map *bpf_map_from_imm(const struct bpf_prog *prog, + unsigned long addr) +{ + int i; + + for (i = 0; i < prog->aux->used_map_cnt; i++) + if (prog->aux->used_maps[i] == (void *)addr) + return prog->aux->used_maps[i]; + return NULL; +} + +static struct bpf_insn *bpf_insn_prepare_dump(const struct bpf_prog *prog) +{ + const struct bpf_map *map; + struct bpf_insn *insns; + u64 imm; + int i; + + insns = kmemdup(prog->insnsi, bpf_prog_insn_size(prog), + GFP_USER); + if (!insns) + return insns; + + for (i = 0; i < prog->len; i++) { + if (insns[i].code == (BPF_JMP | BPF_TAIL_CALL)) { + insns[i].code = BPF_JMP | BPF_CALL; + insns[i].imm = BPF_FUNC_tail_call; + /* fall-through */ + } + if (insns[i].code == (BPF_JMP | BPF_CALL) || + insns[i].code == (BPF_JMP | BPF_CALL_ARGS)) { + if (insns[i].code == (BPF_JMP | BPF_CALL_ARGS)) + insns[i].code = BPF_JMP | BPF_CALL; + if (!bpf_dump_raw_ok()) + insns[i].imm = 0; + continue; + } + + if (insns[i].code != (BPF_LD | BPF_IMM | BPF_DW)) + continue; + + imm = ((u64)insns[i + 1].imm << 32) | (u32)insns[i].imm; + map = bpf_map_from_imm(prog, imm); + if (map) { + insns[i].src_reg = BPF_PSEUDO_MAP_FD; + insns[i].imm = map->id; + insns[i + 1].imm = 0; + continue; + } + + if (!bpf_dump_raw_ok() && + imm == (unsigned long)prog->aux) { + insns[i].imm = 0; + insns[i + 1].imm = 0; + continue; + } + } + + return insns; +} + static int bpf_prog_get_info_by_fd(struct bpf_prog *prog, const union bpf_attr *attr, union bpf_attr __user *uattr) @@ -1608,18 +1669,34 @@ static int bpf_prog_get_info_by_fd(struct bpf_prog *prog, ulen = info.jited_prog_len; info.jited_prog_len = prog->jited_len; if (info.jited_prog_len && ulen) { - uinsns = u64_to_user_ptr(info.jited_prog_insns); - ulen = min_t(u32, info.jited_prog_len, ulen); - if (copy_to_user(uinsns, prog->bpf_func, ulen)) - return -EFAULT; + if (bpf_dump_raw_ok()) { + uinsns = u64_to_user_ptr(info.jited_prog_insns); + ulen = min_t(u32, info.jited_prog_len, ulen); + if (copy_to_user(uinsns, prog->bpf_func, ulen)) + return -EFAULT; + } else { + info.jited_prog_insns = 0; + } } ulen = info.xlated_prog_len; info.xlated_prog_len = bpf_prog_insn_size(prog); if (info.xlated_prog_len && ulen) { + struct bpf_insn *insns_sanitized; + bool fault; + + if (prog->blinded && !bpf_dump_raw_ok()) { + info.xlated_prog_insns = 0; + goto done; + } + insns_sanitized = bpf_insn_prepare_dump(prog); + if (!insns_sanitized) + return -ENOMEM; uinsns = u64_to_user_ptr(info.xlated_prog_insns); ulen = min_t(u32, info.xlated_prog_len, ulen); - if (copy_to_user(uinsns, prog->insnsi, ulen)) + fault = copy_to_user(uinsns, insns_sanitized, ulen); + kfree(insns_sanitized); + if (fault) return -EFAULT; } diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 3c3eec58b3e81..4ae46b2cba880 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -4427,9 +4427,12 @@ static int do_check(struct bpf_verifier_env *env) } if (env->log.level) { + const struct bpf_insn_cbs cbs = { + .cb_print = verbose, + }; + verbose(env, "%d: ", insn_idx); - print_bpf_insn(verbose, env, insn, - env->allow_ptr_leaks); + print_bpf_insn(&cbs, env, insn, env->allow_ptr_leaks); } err = ext_analyzer_insn_hook(env, insn_idx, prev_insn_idx); @@ -5017,14 +5020,14 @@ static int jit_subprogs(struct bpf_verifier_env *env) { struct bpf_prog *prog = env->prog, **func, *tmp; int i, j, subprog_start, subprog_end = 0, len, subprog; - struct bpf_insn *insn = prog->insnsi; + struct bpf_insn *insn; void *old_bpf_func; int err = -ENOMEM; if (env->subprog_cnt == 0) return 0; - for (i = 0; i < prog->len; i++, insn++) { + for (i = 0, insn = prog->insnsi; i < prog->len; i++, insn++) { if (insn->code != (BPF_JMP | BPF_CALL) || insn->src_reg != BPF_PSEUDO_CALL) continue; @@ -5116,6 +5119,25 @@ static int jit_subprogs(struct bpf_verifier_env *env) bpf_prog_lock_ro(func[i]); bpf_prog_kallsyms_add(func[i]); } + + /* Last step: make now unused interpreter insns from main + * prog consistent for later dump requests, so they can + * later look the same as if they were interpreted only. + */ + for (i = 0, insn = prog->insnsi; i < prog->len; i++, insn++) { + unsigned long addr; + + if (insn->code != (BPF_JMP | BPF_CALL) || + insn->src_reg != BPF_PSEUDO_CALL) + continue; + insn->off = env->insn_aux_data[i].call_imm; + subprog = find_subprog(env, i + insn->off + 1); + addr = (unsigned long)func[subprog + 1]->bpf_func; + addr &= PAGE_MASK; + insn->imm = (u64 (*)(u64, u64, u64, u64, u64)) + addr - __bpf_call_base; + } + prog->jited = 1; prog->bpf_func = func[0]->bpf_func; prog->aux->func = func; diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c index 037484ceaeaf7..42ee8892549cc 100644 --- a/tools/bpf/bpftool/prog.c +++ b/tools/bpf/bpftool/prog.c @@ -401,6 +401,88 @@ static int do_show(int argc, char **argv) return err; } +#define SYM_MAX_NAME 256 + +struct kernel_sym { + unsigned long address; + char name[SYM_MAX_NAME]; +}; + +struct dump_data { + unsigned long address_call_base; + struct kernel_sym *sym_mapping; + __u32 sym_count; + char scratch_buff[SYM_MAX_NAME]; +}; + +static int kernel_syms_cmp(const void *sym_a, const void *sym_b) +{ + return ((struct kernel_sym *)sym_a)->address - + ((struct kernel_sym *)sym_b)->address; +} + +static void kernel_syms_load(struct dump_data *dd) +{ + struct kernel_sym *sym; + char buff[256]; + void *tmp, *address; + FILE *fp; + + fp = fopen("/proc/kallsyms", "r"); + if (!fp) + return; + + while (!feof(fp)) { + if (!fgets(buff, sizeof(buff), fp)) + break; + tmp = realloc(dd->sym_mapping, + (dd->sym_count + 1) * + sizeof(*dd->sym_mapping)); + if (!tmp) { +out: + free(dd->sym_mapping); + dd->sym_mapping = NULL; + fclose(fp); + return; + } + dd->sym_mapping = tmp; + sym = &dd->sym_mapping[dd->sym_count]; + if (sscanf(buff, "%p %*c %s", &address, sym->name) != 2) + continue; + sym->address = (unsigned long)address; + if (!strcmp(sym->name, "__bpf_call_base")) { + dd->address_call_base = sym->address; + /* sysctl kernel.kptr_restrict was set */ + if (!sym->address) + goto out; + } + if (sym->address) + dd->sym_count++; + } + + fclose(fp); + + qsort(dd->sym_mapping, dd->sym_count, + sizeof(*dd->sym_mapping), kernel_syms_cmp); +} + +static void kernel_syms_destroy(struct dump_data *dd) +{ + free(dd->sym_mapping); +} + +static struct kernel_sym *kernel_syms_search(struct dump_data *dd, + unsigned long key) +{ + struct kernel_sym sym = { + .address = key, + }; + + return dd->sym_mapping ? + bsearch(&sym, dd->sym_mapping, dd->sym_count, + sizeof(*dd->sym_mapping), kernel_syms_cmp) : NULL; +} + static void print_insn(struct bpf_verifier_env *env, const char *fmt, ...) { va_list args; @@ -410,8 +492,71 @@ static void print_insn(struct bpf_verifier_env *env, const char *fmt, ...) va_end(args); } -static void dump_xlated_plain(void *buf, unsigned int len, bool opcodes) +static const char *print_call_pcrel(struct dump_data *dd, + struct kernel_sym *sym, + unsigned long address, + const struct bpf_insn *insn) { + if (sym) + snprintf(dd->scratch_buff, sizeof(dd->scratch_buff), + "%+d#%s", insn->off, sym->name); + else + snprintf(dd->scratch_buff, sizeof(dd->scratch_buff), + "%+d#0x%lx", insn->off, address); + return dd->scratch_buff; +} + +static const char *print_call_helper(struct dump_data *dd, + struct kernel_sym *sym, + unsigned long address) +{ + if (sym) + snprintf(dd->scratch_buff, sizeof(dd->scratch_buff), + "%s", sym->name); + else + snprintf(dd->scratch_buff, sizeof(dd->scratch_buff), + "0x%lx", address); + return dd->scratch_buff; +} + +static const char *print_call(void *private_data, + const struct bpf_insn *insn) +{ + struct dump_data *dd = private_data; + unsigned long address = dd->address_call_base + insn->imm; + struct kernel_sym *sym; + + sym = kernel_syms_search(dd, address); + if (insn->src_reg == BPF_PSEUDO_CALL) + return print_call_pcrel(dd, sym, address, insn); + else + return print_call_helper(dd, sym, address); +} + +static const char *print_imm(void *private_data, + const struct bpf_insn *insn, + __u64 full_imm) +{ + struct dump_data *dd = private_data; + + if (insn->src_reg == BPF_PSEUDO_MAP_FD) + snprintf(dd->scratch_buff, sizeof(dd->scratch_buff), + "map[id:%u]", insn->imm); + else + snprintf(dd->scratch_buff, sizeof(dd->scratch_buff), + "0x%llx", (unsigned long long)full_imm); + return dd->scratch_buff; +} + +static void dump_xlated_plain(struct dump_data *dd, void *buf, + unsigned int len, bool opcodes) +{ + const struct bpf_insn_cbs cbs = { + .cb_print = print_insn, + .cb_call = print_call, + .cb_imm = print_imm, + .private_data = dd, + }; struct bpf_insn *insn = buf; bool double_insn = false; unsigned int i; @@ -425,7 +570,7 @@ static void dump_xlated_plain(void *buf, unsigned int len, bool opcodes) double_insn = insn[i].code == (BPF_LD | BPF_IMM | BPF_DW); printf("% 4d: ", i); - print_bpf_insn(print_insn, NULL, insn + i, true); + print_bpf_insn(&cbs, NULL, insn + i, true); if (opcodes) { printf(" "); @@ -454,8 +599,15 @@ static void print_insn_json(struct bpf_verifier_env *env, const char *fmt, ...) va_end(args); } -static void dump_xlated_json(void *buf, unsigned int len, bool opcodes) +static void dump_xlated_json(struct dump_data *dd, void *buf, + unsigned int len, bool opcodes) { + const struct bpf_insn_cbs cbs = { + .cb_print = print_insn_json, + .cb_call = print_call, + .cb_imm = print_imm, + .private_data = dd, + }; struct bpf_insn *insn = buf; bool double_insn = false; unsigned int i; @@ -470,7 +622,7 @@ static void dump_xlated_json(void *buf, unsigned int len, bool opcodes) jsonw_start_object(json_wtr); jsonw_name(json_wtr, "disasm"); - print_bpf_insn(print_insn_json, NULL, insn + i, true); + print_bpf_insn(&cbs, NULL, insn + i, true); if (opcodes) { jsonw_name(json_wtr, "opcodes"); @@ -505,6 +657,7 @@ static void dump_xlated_json(void *buf, unsigned int len, bool opcodes) static int do_dump(int argc, char **argv) { struct bpf_prog_info info = {}; + struct dump_data dd = {}; __u32 len = sizeof(info); unsigned int buf_size; char *filepath = NULL; @@ -592,6 +745,14 @@ static int do_dump(int argc, char **argv) goto err_free; } + if ((member_len == &info.jited_prog_len && + info.jited_prog_insns == 0) || + (member_len == &info.xlated_prog_len && + info.xlated_prog_insns == 0)) { + p_err("error retrieving insn dump: kernel.kptr_restrict set?"); + goto err_free; + } + if (filepath) { fd = open(filepath, O_WRONLY | O_CREAT | O_TRUNC, 0600); if (fd < 0) { @@ -608,17 +769,19 @@ static int do_dump(int argc, char **argv) goto err_free; } } else { - if (member_len == &info.jited_prog_len) + if (member_len == &info.jited_prog_len) { disasm_print_insn(buf, *member_len, opcodes); - else + } else { + kernel_syms_load(&dd); if (json_output) - dump_xlated_json(buf, *member_len, opcodes); + dump_xlated_json(&dd, buf, *member_len, opcodes); else - dump_xlated_plain(buf, *member_len, opcodes); + dump_xlated_plain(&dd, buf, *member_len, opcodes); + kernel_syms_destroy(&dd); + } } free(buf); - return 0; err_free: |