/*
* bpf.c BPF common code
*
* This program is free software; you can distribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
* Authors: Daniel Borkmann <daniel@iogearbox.net>
* Jiri Pirko <jiri@resnulli.us>
* Alexei Starovoitov <ast@kernel.org>
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <stdbool.h>
#include <stdint.h>
#include <errno.h>
#include <fcntl.h>
#include <stdarg.h>
#include <limits.h>
#include <assert.h>
#ifdef HAVE_ELF
#include <libelf.h>
#include <gelf.h>
#endif
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/un.h>
#include <sys/vfs.h>
#include <sys/mount.h>
#include <sys/syscall.h>
#include <sys/sendfile.h>
#include <sys/resource.h>
#include <arpa/inet.h>
#include "utils.h"
#include "json_print.h"
#include "bpf_util.h"
#include "bpf_elf.h"
#include "bpf_scm.h"
struct bpf_prog_meta {
const char *type;
const char *subdir;
const char *section;
bool may_uds_export;
};
static const enum bpf_prog_type __bpf_types[] = {
BPF_PROG_TYPE_SCHED_CLS,
BPF_PROG_TYPE_SCHED_ACT,
BPF_PROG_TYPE_XDP,
BPF_PROG_TYPE_LWT_IN,
BPF_PROG_TYPE_LWT_OUT,
BPF_PROG_TYPE_LWT_XMIT,
};
static const struct bpf_prog_meta __bpf_prog_meta[] = {
[BPF_PROG_TYPE_SCHED_CLS] = {
.type = "cls",
.subdir = "tc",
.section = ELF_SECTION_CLASSIFIER,
.may_uds_export = true,
},
[BPF_PROG_TYPE_SCHED_ACT] = {
.type = "act",
.subdir = "tc",
.section = ELF_SECTION_ACTION,
.may_uds_export = true,
},
[BPF_PROG_TYPE_XDP] = {
.type = "xdp",
.subdir = "xdp",
.section = ELF_SECTION_PROG,
},
[BPF_PROG_TYPE_LWT_IN] = {
.type = "lwt_in",
.subdir = "ip",
.section = ELF_SECTION_PROG,
},
[BPF_PROG_TYPE_LWT_OUT] = {
.type = "lwt_out",
.subdir = "ip",
.section = ELF_SECTION_PROG,
},
[BPF_PROG_TYPE_LWT_XMIT] = {
.type = "lwt_xmit",
.subdir = "ip",
.section = ELF_SECTION_PROG,
},
[BPF_PROG_TYPE_LWT_SEG6LOCAL] = {
.type = "lwt_seg6local",
.subdir = "ip",
.section = ELF_SECTION_PROG,
},
};
static const char *bpf_prog_to_subdir(enum bpf_prog_type type)
{
assert(type < ARRAY_SIZE(__bpf_prog_meta) &&
__bpf_prog_meta[type].subdir);
return __bpf_prog_meta[type].subdir;
}
const char *bpf_prog_to_default_section(enum bpf_prog_type type)
{
assert(type < ARRAY_SIZE(__bpf_prog_meta) &&
__bpf_prog_meta[type].section);
return __bpf_prog_meta[type].section;
}
#ifdef HAVE_ELF
static int bpf_obj_open(const char *path, enum bpf_prog_type type,
const char *sec, __u32 ifindex, bool verbose);
#else
static int bpf_obj_open(const char *path, enum bpf_prog_type type,
const char *sec, __u32 ifindex, bool verbose)
{
fprintf(stderr, "No ELF library support compiled in.\n");
errno = ENOSYS;
return -1;
}
#endif
static inline __u64 bpf_ptr_to_u64(const void *ptr)
{
return (__u64)(unsigned long)ptr;
}
static int bpf(int cmd, union bpf_attr *attr, unsigned int size)
{
#ifdef __NR_bpf
return syscall(__NR_bpf, cmd, attr, size);
#else
fprintf(stderr, "No bpf syscall, kernel headers too old?\n");
errno = ENOSYS;
return -1;
#endif
}
static int bpf_map_update(int fd, const void *key, const void *value,
uint64_t flags)
{
union bpf_attr attr = {};
attr.map_fd = fd;
attr.key = bpf_ptr_to_u64(key);
attr.value = bpf_ptr_to_u64(value);
attr.flags = flags;
return bpf(BPF_MAP_UPDATE_ELEM, &attr, sizeof(attr));
}
static int bpf_prog_fd_by_id(uint32_t id)
{
union bpf_attr attr = {};
attr.prog_id = id;
return bpf(BPF_PROG_GET_FD_BY_ID, &attr, sizeof(attr));
}
static int bpf_prog_info_by_fd(int fd, struct bpf_prog_info *info,
uint32_t *info_len)
{
union bpf_attr attr = {};
int ret;
attr.info.bpf_fd = fd;
attr.info.info = bpf_ptr_to_u64(info);
attr.info.info_len = *info_len;
*info_len = 0;
ret = bpf(BPF_OBJ_GET_INFO_BY_FD, &attr, sizeof(attr));
if (!ret)
*info_len = attr.info.info_len;
return ret;
}
int bpf_dump_prog_info(FILE *f, uint32_t id)
{
struct bpf_prog_info info = {};
uint32_t len = sizeof(info);
int fd, ret, dump_ok = 0;
SPRINT_BUF(tmp);
open_json_object("prog");
print_uint(PRINT_ANY, "id", "id %u ", id);
fd = bpf_prog_fd_by_id(id);
if (fd < 0)
goto out;
ret = bpf_prog_info_by_fd(fd, &info, &len);
if (!ret && len) {
int jited = !!info.jited_prog_len;
print_string(PRINT_ANY, "tag", "tag %s ",
hexstring_n2a(info.tag, sizeof(info.tag),
tmp, sizeof(tmp)));
print_uint(PRINT_JSON, "jited", NULL, jited);
if (jited && !is_json_context())
fprintf(f, "jited ");
dump_ok = 1;
}
close(fd);
out:
close_json_object();
return dump_ok;
}
static int bpf_parse_string(char *arg, bool from_file, __u16 *bpf_len,
char **bpf_string, bool *need_release,
const char separator)
{
char sp;
if (from_file) {
size_t tmp_len, op_len = sizeof("65535 255 255 4294967295,");
char *tmp_string, *pos, c_prev = ' ';
FILE *fp;
int c;
tmp_len = sizeof("4096,") + BPF_MAXINSNS * op_len;
tmp_string = pos = calloc(1, tmp_len);
if (tmp_string == NULL)
return -ENOMEM;
fp = fopen(arg, "r");
if (fp == NULL) {
perror("Cannot fopen");
free(tmp_string);
return -ENOENT;
}
while ((c = fgetc(fp)) != EOF) {
switch (c) {
case '\n':
if (c_prev != ',')
*(pos++) = ',';
c_prev = ',';
break;
case ' ':
case '\t':
if (c_prev != ' ')
*(pos++) = c;
c_prev = ' ';
break;
default:
*(pos++) = c;
c_prev = c;
}
if (pos - tmp_string == tmp_len)
break;
}
if (!feof(fp)) {
free(tmp_string);
fclose(fp);
return -E2BIG;
}
fclose(fp);
*pos = 0;
*need_release = true;
*bpf_string = tmp_string;
} else {
*need_release = false;
*bpf_string = arg;
}
if (sscanf(*bpf_string, "%hu%c", bpf_len, &sp) != 2 ||
sp != separator) {
if (*need_release)
free(*bpf_string);
return -EINVAL;
}
return 0;
}
static int bpf_ops_parse(int argc, char **argv, struct sock_filter *bpf_ops,
bool from_file)
{
char *bpf_string, *token, separator = ',';
int ret = 0, i = 0;
bool need_release;
__u16 bpf_len = 0;
if (argc < 1)
return -EINVAL;
if (bpf_parse_string(argv[0], from_file, &bpf_len, &bpf_string,
&need_release, separator))
return -EINVAL;
if (bpf_len == 0 || bpf_len > BPF_MAXINSNS) {
ret = -EINVAL;
goto out;
}
token = bpf_string;
while ((token = strchr(token, separator)) && (++token)[0]) {
if (i >= bpf_len) {
fprintf(stderr, "Real program length exceeds encoded length parameter!\n");
ret = -EINVAL;
goto out;
}
if (sscanf(token, "%hu %hhu %hhu %u,",
&bpf_ops[i].code, &bpf_ops[i].jt,
&bpf_ops[i].jf, &bpf_ops[i].k) != 4) {
fprintf(stderr, "Error at instruction %d!\n", i);
ret = -EINVAL;
goto out;
}
i++;
}
if (i != bpf_len) {
fprintf(stderr, "Parsed program length is less than encoded length parameter!\n");
ret = -EINVAL;
goto out;
}
ret = bpf_len;
out:
if (need_release)
free(bpf_string);
return ret;
}
void bpf_print_ops(struct rtattr *bpf_ops, __u16 len)
{
struct sock_filter *ops = RTA_DATA(bpf_ops);
int i;
if (len == 0)
return;
open_json_object("bytecode");
print_uint(PRINT_ANY, "length", "bytecode \'%u,", len);
open_json_array(PRINT_JSON, "insns");
for (i = 0; i < len; i++) {
open_json_object(NULL);
print_hu(PRINT_ANY, "code", "%hu ", ops[i].code);
print_hhu(PRINT_ANY, "jt", "%hhu ", ops[i].jt);
print_hhu(PRINT_ANY, "jf", "%hhu ", ops[i].jf);
if (i == len - 1)
print_uint(PRINT_ANY, "k", "%u\'", ops[i].k);
else
print_uint(PRINT_ANY, "k", "%u,", ops[i].k);
close_json_object();
}
close_json_array(PRINT_JSON, NULL);
close_json_object();
}
static void bpf_map_pin_report(const struct bpf_elf_map *pin,
const struct bpf_elf_map *obj)
{
fprintf(stderr, "Map specification differs from pinned file!\n");
if (obj->type != pin->type)
fprintf(stderr, " - Type: %u (obj) != %u (pin)\n",
obj->type, pin->type);
if (obj->size_key != pin->size_key)
fprintf(stderr, " - Size key: %u (obj) != %u (pin)\n",
obj->size_key, pin->size_key);
if (obj->size_value != pin->size_value)
fprintf(stderr, " - Size value: %u (obj) != %u (pin)\n",
obj->size_value, pin->size_value);
if (obj->max_elem != pin->max_elem)
fprintf(stderr, " - Max elems: %u (obj) != %u (pin)\n",
obj->max_elem, pin->max_elem);
if (obj->flags != pin->flags)
fprintf(stderr, " - Flags: %#x (obj) != %#x (pin)\n",
obj->flags, pin->flags);
fprintf(stderr, "\n");
}
struct bpf_prog_data {
unsigned int type;
unsigned int jited;
};
struct bpf_map_ext {
struct bpf_prog_data owner;
unsigned int btf_id_key;
unsigned int btf_id_val;
};
static int bpf_derive_elf_map_from_fdinfo(int fd, struct bpf_elf_map *map,
struct bpf_map_ext *ext)
{
unsigned int val, owner_type = 0, owner_jited = 0;
char file[PATH_MAX], buff[4096];
FILE *fp;
snprintf(file, sizeof(file), "/proc/%d/fdinfo/%d", getpid(), fd);
memset(map, 0, sizeof(*map));
fp = fopen(file, "r");
if (!fp) {
fprintf(stderr, "No procfs support?!\n");
return -EIO;
}
while (fgets(buff, sizeof(buff), fp)) {
if (sscanf(buff, "map_type:\t%u", &val) == 1)
map->type = val;
else if (sscanf(buff, "key_size:\t%u", &val) == 1)
map->size_key = val;
else if (sscanf(buff, "value_size:\t%u", &val) == 1)
map->size_value = val;
else if (sscanf(buff, "max_entries:\t%u", &val) == 1)
map->max_elem = val;
else if (sscanf(buff, "map_flags:\t%i", &val) == 1)
map->flags = val;
else if (sscanf(buff, "owner_prog_type:\t%i", &val) == 1)
owner_type = val;
else if (sscanf(buff, "owner_jited:\t%i", &val) == 1)
owner_jited = val;
}
fclose(fp);
if (ext) {
memset(ext, 0, sizeof(*ext));
ext->owner.type = owner_type;
ext->owner.jited = owner_jited;
}
return 0;
}
static int bpf_map_selfcheck_pinned(int fd, const struct bpf_elf_map *map,
struct bpf_map_ext *ext, int length,
enum bpf_prog_type type)
{
struct bpf_elf_map tmp, zero = {};
int ret;
ret = bpf_derive_elf_map_from_fdinfo(fd, &tmp, ext);
if (ret < 0)
return ret;
/* The decision to reject this is on kernel side eventually, but
* at least give the user a chance to know what's wrong.
*/
if (ext->owner.type && ext->owner.type != type)
fprintf(stderr, "Program array map owner types differ: %u (obj) != %u (pin)\n",
type, ext->owner.type);
if (!memcmp(&tmp, map, length)) {
return 0;
} else {
/* If kernel doesn't have eBPF-related fdinfo, we cannot do much,
* so just accept it. We know we do have an eBPF fd and in this
* case, everything is 0. It is guaranteed that no such map exists
* since map type of 0 is unloadable BPF_MAP_TYPE_UNSPEC.
*/
if (!memcmp(&tmp, &zero, length))
return 0;
bpf_map_pin_report(&tmp, map);
return -EINVAL;
}
}
static int bpf_mnt_fs(const char *target)
{
bool bind_done = false;
while (mount("", target, "none", MS_PRIVATE | MS_REC, NULL)) {
if (errno != EINVAL || bind_done) {
fprintf(stderr, "mount --make-private %s failed: %s\n",
target, strerror(errno));
return -1;
}
if (mount(target, target, "none", MS_BIND, NULL)) {
fprintf(stderr, "mount --bind %s %s failed: %s\n",
target, target, strerror(errno));
return -1;
}
bind_done = true;
}
if (mount("bpf", target, "bpf", 0, "mode=0700")) {
fprintf(stderr, "mount -t bpf bpf %s failed: %s\n",
target, strerror(errno));
return -1;
}
return 0;
}
static int bpf_mnt_check_target(const char *target)
{
struct stat sb = {};
int ret;
ret = stat(target, &sb);
if (ret) {
ret = mkdir(target, S_IRWXU);
if (ret) {
fprintf(stderr, "mkdir %s failed: %s\n", target,
strerror(errno));
return ret;
}
}
return 0;
}
static int bpf_valid_mntpt(const char *mnt, unsigned long magic)
{
struct statfs st_fs;
if (statfs(mnt, &st_fs) < 0)
return -ENOENT;
if ((unsigned long)st_fs.f_type != magic)
return -ENOENT;
return 0;
}
static const char *bpf_find_mntpt_single(unsigned long magic, char *mnt,
int len, const char *mntpt)
{
int ret;
ret = bpf_valid_mntpt(mntpt, magic);
if (!ret) {
strlcpy(mnt, mntpt, len);
return mnt;
}
return NULL;
}
static const char *bpf_find_mntpt(const char *fstype, unsigned long magic,
char *mnt, int len,
const char * const *known_mnts)
{
const char * const *ptr;
char type[100];
FILE *fp;
if (known_mnts) {
ptr = known_mnts;
while (*ptr) {
if (bpf_find_mntpt_single(magic, mnt, len, *ptr))
return mnt;
ptr++;
}
}
if (len != PATH_MAX)
return NULL;
fp = fopen("/proc/mounts", "r");
if (fp == NULL)
return NULL;
while (fscanf(fp, "%*s %" textify(PATH_MAX) "s %99s %*s %*d %*d\n",
mnt, type) == 2) {
if (strcmp(type, fstype) == 0)
break;
}
fclose(fp);
if (strcmp(type, fstype) != 0)
return NULL;
return mnt;
}
int bpf_trace_pipe(void)
{
char tracefs_mnt[PATH_MAX] = TRACE_DIR_MNT;
static const char * const tracefs_known_mnts[] = {
TRACE_DIR_MNT,
"/sys/kernel/debug/tracing",
"/tracing",
"/trace",
0,
};
int fd_in, fd_out = STDERR_FILENO;
char tpipe[PATH_MAX];
const char *mnt;
mnt = bpf_find_mntpt("tracefs", TRACEFS_MAGIC, tracefs_mnt,
sizeof(tracefs_mnt), tracefs_known_mnts);
if (!mnt) {
fprintf(stderr, "tracefs not mounted?\n");
return -1;
}
snprintf(tpipe, sizeof(tpipe), "%s/trace_pipe", mnt);
fd_in = open(tpipe, O_RDONLY);
if (fd_in < 0)
return -1;
fprintf(stderr, "Running! Hang up with ^C!\n\n");
while (1) {
static char buff[4096];
ssize_t ret;
ret = read(fd_in, buff, sizeof(buff));
if (ret > 0 && write(fd_out, buff, ret) == ret)
continue;
break;
}
close(fd_in);
return -1;
}
static int bpf_gen_global(const char *bpf_sub_dir)
{
char bpf_glo_dir[PATH_MAX];
int ret;
snprintf(bpf_glo_dir, sizeof(bpf_glo_dir), "%s/%s/",
bpf_sub_dir, BPF_DIR_GLOBALS);
ret = mkdir(bpf_glo_dir, S_IRWXU);
if (ret && errno != EEXIST) {
fprintf(stderr, "mkdir %s failed: %s\n", bpf_glo_dir,
strerror(errno));
return ret;
}
return 0;
}
static int bpf_gen_master(const char *base, const char *name)
{
char bpf_sub_dir[PATH_MAX + NAME_MAX + 1];
int ret;
snprintf(bpf_sub_dir, sizeof(bpf_sub_dir), "%s%s/", base, name);
ret = mkdir(bpf_sub_dir, S_IRWXU);
if (ret && errno != EEXIST) {
fprintf(stderr, "mkdir %s failed: %s\n", bpf_sub_dir,
strerror(errno));
return ret;
}
return bpf_gen_global(bpf_sub_dir);
}
static int bpf_slave_via_bind_mnt(const char *full_name,
const char *full_link)
{
int ret;
ret = mkdir(full_name, S_IRWXU);
if (ret) {
assert(errno != EEXIST);
fprintf(stderr, "mkdir %s failed: %s\n", full_name,
strerror(errno));
return ret;
}
ret = mount(full_link, full_name, "none", MS_BIND, NULL);
if (ret) {
rmdir(full_name);
fprintf(stderr, "mount --bind %s %s failed: %s\n",
full_link, full_name, strerror(errno));
}
return ret;
}
static int bpf_gen_slave(const char *base, const char *name,
const char *link)
{
char bpf_lnk_dir[PATH_MAX + NAME_MAX + 1];
char bpf_sub_dir[PATH_MAX + NAME_MAX];
struct stat sb = {};
int ret;
snprintf(bpf_lnk_dir, sizeof(bpf_lnk_dir), "%s%s/", base, link);
snprintf(bpf_sub_dir, sizeof(bpf_sub_dir), "%s%s", base, name);
ret = symlink(bpf_lnk_dir, bpf_sub_dir);
if (ret) {
if (errno != EEXIST) {
if (errno != EPERM) {
fprintf(stderr, "symlink %s failed: %s\n",
bpf_sub_dir, strerror(errno));
return ret;
}
return bpf_slave_via_bind_mnt(bpf_sub_dir,
bpf_lnk_dir);
}
ret = lstat(bpf_sub_dir, &sb);
if (ret) {
fprintf(stderr, "lstat %s failed: %s\n",
bpf_sub_dir, strerror(errno));
return ret;
}
if ((sb.st_mode & S_IFMT) != S_IFLNK)
return bpf_gen_global(bpf_sub_dir);
}
return 0;
}
static int bpf_gen_hierarchy(const char *base)
{
int ret, i;
ret = bpf_gen_master(base, bpf_prog_to_subdir(__bpf_types[0]));
for (i = 1; i < ARRAY_SIZE(__bpf_types) && !ret; i++)
ret = bpf_gen_slave(base,
bpf_prog_to_subdir(__bpf_types[i]),
bpf_prog_to_subdir(__bpf_types[0]));
return ret;
}
static const char *bpf_get_work_dir(enum bpf_prog_type type)
{
static char bpf_tmp[PATH_MAX] = BPF_DIR_MNT;
static char bpf_wrk_dir[PATH_MAX];
static const char *mnt;
static bool bpf_mnt_cached;
const char *mnt_env = getenv(BPF_ENV_MNT);
static const char * const bpf_known_mnts[] = {
BPF_DIR_MNT,
"/bpf",
0,
};
int ret;
if (bpf_mnt_cached) {
const char *out = mnt;
if (out && type) {
snprintf(bpf_tmp, sizeof(bpf_tmp), "%s%s/",
out, bpf_prog_to_subdir(type));
out = bpf_tmp;
}
return out;
}
if (mnt_env)
mnt = bpf_find_mntpt_single(BPF_FS_MAGIC, bpf_tmp,
sizeof(bpf_tmp), mnt_env);
else
mnt = bpf_find_mntpt("bpf", BPF_FS_MAGIC, bpf_tmp,
sizeof(bpf_tmp), bpf_known_mnts);
if (!mnt) {
mnt = mnt_env ? : BPF_DIR_MNT;
ret = bpf_mnt_check_target(mnt);
if (!ret)
ret = bpf_mnt_fs(mnt);
if (ret) {
mnt = NULL;
goto out;
}
}
ret = snprintf(bpf_wrk_dir, sizeof(bpf_wrk_dir), "%s/", mnt);
if (ret < 0 || ret >= sizeof(bpf_wrk_dir)) {
mnt = NULL;
goto out;
}
ret = bpf_gen_hierarchy(bpf_wrk_dir);
if (ret) {
mnt = NULL;
goto out;
}
mnt = bpf_wrk_dir;
out:
bpf_mnt_cached = true;
return mnt;
}
static int bpf_obj_get(const char *pathname, enum bpf_prog_type type)
{
union bpf_attr attr = {};
char tmp[PATH_MAX];
if (strlen(pathname) > 2 && pathname[0] == 'm' &&
pathname[1] == ':' && bpf_get_work_dir(type)) {
snprintf(tmp, sizeof(tmp), "%s/%s",
bpf_get_work_dir(type), pathname + 2);
pathname = tmp;
}
attr.pathname = bpf_ptr_to_u64(pathname);
return bpf(BPF_OBJ_GET, &attr, sizeof(attr));
}
static int bpf_obj_pinned(const char *pathname, enum bpf_prog_type type)
{
int prog_fd = bpf_obj_get(pathname, type);
if (prog_fd < 0)
fprintf(stderr, "Couldn\'t retrieve pinned program \'%s\': %s\n",
pathname, strerror(errno));
return prog_fd;
}
static int bpf_do_parse(struct bpf_cfg_in *cfg, const bool *opt_tbl)
{
const char *file, *section, *uds_name;
bool verbose = false;
int i, ret, argc;
char **argv;
argv = cfg->argv;
argc = cfg->argc;
if (opt_tbl[CBPF_BYTECODE] &&
(matches(*argv, "bytecode") == 0 ||
strcmp(*argv, "bc") == 0)) {
cfg->mode = CBPF_BYTECODE;
} else if (opt_tbl[CBPF_FILE] &&
(matches(*argv, "bytecode-file") == 0 ||
strcmp(*argv, "bcf") == 0)) {
cfg->mode = CBPF_FILE;
} else if (opt_tbl[EBPF_OBJECT] &&
(matches(*argv, "object-file") == 0 ||
strcmp(*argv, "obj") == 0)) {
cfg->mode = EBPF_OBJECT;
} else if (opt_tbl[EBPF_PINNED] &&
(matches(*argv, "object-pinned") == 0 ||
matches(*argv, "pinned") == 0 ||
matches(*argv, "fd") == 0)) {
cfg->mode = EBPF_PINNED;
} else {
fprintf(stderr, "What mode is \"%s\"?\n", *argv);
return -1;
}
NEXT_ARG();
file = section = uds_name = NULL;
if (cfg->mode == EBPF_OBJECT || cfg->mode == EBPF_PINNED) {
file = *argv;
NEXT_ARG_FWD();
if (cfg->type == BPF_PROG_TYPE_UNSPEC) {
if (argc > 0 && matches(*argv, "type") == 0) {
NEXT_ARG();
for (i = 0; i < ARRAY_SIZE(__bpf_prog_meta);
i++) {
if (!__bpf_prog_meta[i].type)
continue;
if (!matches(*argv,
__bpf_prog_meta[i].type)) {
cfg->type = i;
break;
}
}
if (cfg->type == BPF_PROG_TYPE_UNSPEC) {
fprintf(stderr, "What type is \"%s\"?\n",
*argv);
return -1;
}
NEXT_ARG_FWD();
} else {
cfg->type = BPF_PROG_TYPE_SCHED_CLS;
}
}
section = bpf_prog_to_default_section(cfg->type);
if (argc > 0 && matches(*argv, "section") == 0) {
NEXT_ARG();
section = *argv;
NEXT_ARG_FWD();
}
if (__bpf_prog_meta[cfg->type].may_uds_export) {
uds_name = getenv(BPF_ENV_UDS);
if (argc > 0 && !uds_name &&
matches(*argv, "export") == 0) {
NEXT_ARG();
uds_name = *argv;
NEXT_ARG_FWD();
}
}
if (argc > 0 && matches(*argv, "verbose") == 0) {
verbose = true;
NEXT_ARG_FWD();
}
PREV_ARG();
}
if (cfg->mode == CBPF_BYTECODE || cfg->mode == CBPF_FILE) {
ret = bpf_ops_parse(argc, argv, cfg->opcodes,
cfg->mode == CBPF_FILE);
cfg->n_opcodes = ret;
} else if (cfg->mode == EBPF_OBJECT) {
ret = 0; /* program will be loaded by load stage */
} else if (cfg->mode == EBPF_PINNED) {
ret = bpf_obj_pinned(file, cfg->type);
cfg->prog_fd = ret;
} else {
return -1;
}
cfg->object = file;
cfg->section = section;
cfg->uds = uds_name;
cfg->argc = argc;
cfg->argv = argv;
cfg->verbose = verbose;
return ret;
}
static int bpf_do_load(struct bpf_cfg_in *cfg)
{
if (cfg->mode == EBPF_OBJECT) {
cfg->prog_fd = bpf_obj_open(cfg->object, cfg->type,
cfg->section, cfg->ifindex,
cfg->verbose);
return cfg->prog_fd;
}
return 0;
}
int bpf_load_common(struct bpf_cfg_in *cfg, const struct bpf_cfg_ops *ops,
void *nl)
{
char annotation[256];
int ret;
ret = bpf_do_load(cfg);
if (ret < 0)
return ret;
if (cfg->mode == CBPF_BYTECODE || cfg->mode == CBPF_FILE)
ops->cbpf_cb(nl, cfg->opcodes, cfg->n_opcodes);
if (cfg->mode == EBPF_OBJECT || cfg->mode == EBPF_PINNED) {
snprintf(annotation, sizeof(annotation), "%s:[%s]",
basename(cfg->object), cfg->mode == EBPF_PINNED ?
"*fsobj" : cfg->section);
ops->ebpf_cb(nl, cfg->prog_fd, annotation);
}
return 0;
}
int bpf_parse_common(struct bpf_cfg_in *cfg, const struct bpf_cfg_ops *ops)
{
bool opt_tbl[BPF_MODE_MAX] = {};
if (ops->cbpf_cb) {
opt_tbl[CBPF_BYTECODE] = true;
opt_tbl[CBPF_FILE] = true;
}
if (ops->ebpf_cb) {
opt_tbl[EBPF_OBJECT] = true;
opt_tbl[EBPF_PINNED] = true;
}
return bpf_do_parse(cfg, opt_tbl);
}
int bpf_parse_and_load_common(struct bpf_cfg_in *cfg,
const struct bpf_cfg_ops *ops, void *nl)
{
int ret;
ret = bpf_parse_common(cfg, ops);
if (ret < 0)
return ret;
return bpf_load_common(cfg, ops, nl);
}
int bpf_graft_map(const char *map_path, uint32_t *key, int argc, char **argv)
{
const bool opt_tbl[BPF_MODE_MAX] = {
[EBPF_OBJECT] = true,
[EBPF_PINNED] = true,
};
const struct bpf_elf_map test = {
.type = BPF_MAP_TYPE_PROG_ARRAY,
.size_key = sizeof(int),
.size_value = sizeof(int),
};
struct bpf_cfg_in cfg = {
.type = BPF_PROG_TYPE_UNSPEC,
.argc = argc,
.argv = argv,
};
struct bpf_map_ext ext = {};
int ret, prog_fd, map_fd;
uint32_t map_key;
ret = bpf_do_parse(&cfg, opt_tbl);
if (ret < 0)
return ret;
ret = bpf_do_load(&cfg);
if (ret < 0)
return ret;
prog_fd = cfg.prog_fd;
if (key) {
map_key = *key;
} else {
ret = sscanf(cfg.section, "%*i/%i", &map_key);
if (ret != 1) {
fprintf(stderr, "Couldn\'t infer map key from section name! Please provide \'key\' argument!\n");
ret = -EINVAL;
goto out_prog;
}
}
map_fd = bpf_obj_get(map_path, cfg.type);
if (map_fd < 0) {
fprintf(stderr, "Couldn\'t retrieve pinned map \'%s\': %s\n",
map_path, strerror(errno));
ret = map_fd;
goto out_prog;
}
ret = bpf_map_selfcheck_pinned(map_fd, &test, &ext,
offsetof(struct bpf_elf_map, max_elem),
cfg.type);
if (ret < 0) {
fprintf(stderr, "Map \'%s\' self-check failed!\n", map_path);
goto out_map;
}
ret = bpf_map_update(map_fd, &map_key, &prog_fd, BPF_ANY);
if (ret < 0)
fprintf(stderr, "Map update failed: %s\n", strerror(errno));
out_map:
close(map_fd);
out_prog:
close(prog_fd);
return ret;
}
int bpf_prog_attach_fd(int prog_fd, int target_fd, enum bpf_attach_type type)
{
union bpf_attr attr = {};
attr.target_fd = target_fd;
attr.attach_bpf_fd = prog_fd;
attr.attach_type = type;
return bpf(BPF_PROG_ATTACH, &attr, sizeof(attr));
}
int bpf_prog_detach_fd(int target_fd, enum bpf_attach_type type)
{
union bpf_attr attr = {};
attr.target_fd = target_fd;
attr.attach_type = type;
return bpf(BPF_PROG_DETACH, &attr, sizeof(attr));
}
static int bpf_prog_load_dev(enum bpf_prog_type type,
const struct bpf_insn *insns, size_t size_insns,
const char *license, __u32 ifindex,
char *log, size_t size_log)
{
union bpf_attr attr = {};
attr.prog_type = type;
attr.insns = bpf_ptr_to_u64(insns);
attr.insn_cnt = size_insns / sizeof(struct bpf_insn);
attr.license = bpf_ptr_to_u64(license);
attr.prog_ifindex = ifindex;
if (size_log > 0) {
attr.log_buf = bpf_ptr_to_u64(log);
attr.log_size = size_log;
attr.log_level = 1;
}
return bpf(BPF_PROG_LOAD, &attr, sizeof(attr));
}
int bpf_prog_load(enum bpf_prog_type type, const struct bpf_insn *insns,
size_t size_insns, const char *license, char *log,
size_t size_log)
{
return bpf_prog_load_dev(type, insns, size_insns, license, 0,
log, size_log);
}
#ifdef HAVE_ELF
struct bpf_elf_prog {
enum bpf_prog_type type;
struct bpf_insn *insns;
unsigned int insns_num;
size_t size;
const char *license;
};
struct bpf_hash_entry {
unsigned int pinning;
const char *subpath;
struct bpf_hash_entry *next;
};
struct bpf_config {
unsigned int jit_enabled;
};
struct bpf_btf {
const struct btf_header *hdr;
const void *raw;
const char *strings;
const struct btf_type **types;
int types_num;
};
struct bpf_elf_ctx {
struct bpf_config cfg;
Elf *elf_fd;
GElf_Ehdr elf_hdr;
Elf_Data *sym_tab;
Elf_Data *str_tab;
Elf_Data *btf_data;
char obj_uid[64];
int obj_fd;
int btf_fd;
int map_fds[ELF_MAX_MAPS];
struct bpf_elf_map maps[ELF_MAX_MAPS];
struct bpf_map_ext maps_ext[ELF_MAX_MAPS];
struct bpf_elf_prog prog_text;
struct bpf_btf btf;
int sym_num;
int map_num;
int map_len;
bool *sec_done;
int sec_maps;
int sec_text;
int sec_btf;
char license[ELF_MAX_LICENSE_LEN];
enum bpf_prog_type type;
__u32 ifindex;
bool verbose;
bool noafalg;
struct bpf_elf_st stat;
struct bpf_hash_entry *ht[256];
char *log;
size_t log_size;
};
struct bpf_elf_sec_data {
GElf_Shdr sec_hdr;
Elf_Data *sec_data;
const char *sec_name;
};
struct bpf_map_data {
int *fds;
const char *obj;
struct bpf_elf_st *st;
struct bpf_elf_map *ent;
};
static bool bpf_log_has_data(struct bpf_elf_ctx *ctx)
{
return ctx->log && ctx->log[0];
}
static __check_format_string(2, 3) void
bpf_dump_error(struct bpf_elf_ctx *ctx, const char *format, ...)
{
va_list vl;
va_start(vl, format);
vfprintf(stderr, format, vl);
va_end(vl);
if (bpf_log_has_data(ctx)) {
if (ctx->verbose) {
fprintf(stderr, "%s\n", ctx->log);
} else {
unsigned int off = 0, len = strlen(ctx->log);
if (len > BPF_MAX_LOG) {
off = len - BPF_MAX_LOG;
fprintf(stderr, "Skipped %u bytes, use \'verb\' option for the full verbose log.\n[...]\n",
off);
}
fprintf(stderr, "%s\n", ctx->log + off);
}
memset(ctx->log, 0, ctx->log_size);
}
}
static int bpf_log_realloc(struct bpf_elf_ctx *ctx)
{
const size_t log_max = UINT_MAX >> 8;
size_t log_size = ctx->log_size;
char *ptr;
if (!ctx->log) {
log_size = 65536;
} else if (log_size < log_max) {
log_size <<= 1;
if (log_size > log_max)
log_size = log_max;
} else {
return -EINVAL;
}
ptr = realloc(ctx->log, log_size);
if (!ptr)
return -ENOMEM;
ptr[0] = 0;
ctx->log = ptr;
ctx->log_size = log_size;
return 0;
}
static int bpf_map_create(enum bpf_map_type type, uint32_t size_key,
uint32_t size_value, uint32_t max_elem,
uint32_t flags, int inner_fd, int btf_fd,
uint32_t ifindex, uint32_t btf_id_key,
uint32_t btf_id_val)
{
union bpf_attr attr = {};
attr.map_type = type;
attr.key_size = size_key;
attr.value_size = inner_fd ? sizeof(int) : size_value;
attr.max_entries = max_elem;
attr.map_flags = flags;
attr.inner_map_fd = inner_fd;
attr.map_ifindex = ifindex;
attr.btf_fd = btf_fd;
attr.btf_key_type_id = btf_id_key;
attr.btf_value_type_id = btf_id_val;
return bpf(BPF_MAP_CREATE, &attr, sizeof(attr));
}
static int bpf_btf_load(void *btf, size_t size_btf,
char *log, size_t size_log)
{
union bpf_attr attr = {};
attr.btf = bpf_ptr_to_u64(btf);
attr.btf_size = size_btf;
if (size_log > 0) {
attr.btf_log_buf = bpf_ptr_to_u64(log);
attr.btf_log_size = size_log;
attr.btf_log_level = 1;
}
return bpf(BPF_BTF_LOAD, &attr, sizeof(attr));
}
static int bpf_obj_pin(int fd, const char *pathname)
{
union bpf_attr attr = {};
attr.pathname = bpf_ptr_to_u64(pathname);
attr.bpf_fd = fd;
return bpf(BPF_OBJ_PIN, &attr, sizeof(attr));
}
static int bpf_obj_hash(const char *object, uint8_t *out, size_t len)
{
struct sockaddr_alg alg = {
.salg_family = AF_ALG,
.salg_type = "hash",
.salg_name = "sha1",
};
int ret, cfd, ofd, ffd;
struct stat stbuff;
ssize_t size;
if (!object || len != 20)
return -EINVAL;
cfd = socket(AF_ALG, SOCK_SEQPACKET, 0);
if (cfd < 0)
return cfd;
ret = bind(cfd, (struct sockaddr *)&alg, sizeof(alg));
if (ret < 0)
goto out_cfd;
ofd = accept(cfd, NULL, 0);
if (ofd < 0) {
ret = ofd;
goto out_cfd;
}
ffd = open(object, O_RDONLY);
if (ffd < 0) {
fprintf(stderr, "Error opening object %s: %s\n",
object, strerror(errno));
ret = ffd;
goto out_ofd;
}
ret = fstat(ffd, &stbuff);
if (ret < 0) {
fprintf(stderr, "Error doing fstat: %s\n",
strerror(errno));
goto out_ffd;
}
size = sendfile(ofd, ffd, NULL, stbuff.st_size);
if (size != stbuff.st_size) {
fprintf(stderr, "Error from sendfile (%zd vs %zu bytes): %s\n",
size, stbuff.st_size, strerror(errno));
ret = -1;
goto out_ffd;
}
size = read(ofd, out, len);
if (size != len) {
fprintf(stderr, "Error from read (%zd vs %zu bytes): %s\n",
size, len, strerror(errno));
ret = -1;
} else {
ret = 0;
}
out_ffd:
close(ffd);
out_ofd:
close(ofd);
out_cfd:
close(cfd);
return ret;
}
static void bpf_init_env(void)
{
struct rlimit limit = {
.rlim_cur = RLIM_INFINITY,
.rlim_max = RLIM_INFINITY,
};
/* Don't bother in case we fail! */
setrlimit(RLIMIT_MEMLOCK, &limit);
if (!bpf_get_work_dir(BPF_PROG_TYPE_UNSPEC))
fprintf(stderr, "Continuing without mounted eBPF fs. Too old kernel?\n");
}
static const char *bpf_custom_pinning(const struct bpf_elf_ctx *ctx,
uint32_t pinning)
{
struct bpf_hash_entry *entry;
entry = ctx->ht[pinning & (ARRAY_SIZE(ctx->ht) - 1)];
while (entry && entry->pinning != pinning)
entry = entry->next;
return entry ? entry->subpath : NULL;
}
static bool bpf_no_pinning(const struct bpf_elf_ctx *ctx,
uint32_t pinning)
{
switch (pinning) {
case PIN_OBJECT_NS:
case PIN_GLOBAL_NS:
return false;
case PIN_NONE:
return true;
default:
return !bpf_custom_pinning(ctx, pinning);
}
}
static void bpf_make_pathname(char *pathname, size_t len, const char *name,
const struct bpf_elf_ctx *ctx, uint32_t pinning)
{
switch (pinning) {
case PIN_OBJECT_NS:
snprintf(pathname, len, "%s/%s/%s",
bpf_get_work_dir(ctx->type),
ctx->obj_uid, name);
break;
case PIN_GLOBAL_NS:
snprintf(pathname, len, "%s/%s/%s",
bpf_get_work_dir(ctx->type),
BPF_DIR_GLOBALS, name);
break;
default:
snprintf(pathname, len, "%s/../%s/%s",
bpf_get_work_dir(ctx->type),
bpf_custom_pinning(ctx, pinning), name);
break;
}
}
static int bpf_probe_pinned(const char *name, const struct bpf_elf_ctx *ctx,
uint32_t pinning)
{
char pathname[PATH_MAX];
if (bpf_no_pinning(ctx, pinning) || !bpf_get_work_dir(ctx->type))
return 0;
bpf_make_pathname(pathname, sizeof(pathname), name, ctx, pinning);
return bpf_obj_get(pathname, ctx->type);
}
static int bpf_make_obj_path(const struct bpf_elf_ctx *ctx)
{
char tmp[PATH_MAX];
int ret;
snprintf(tmp, sizeof(tmp), "%s/%s", bpf_get_work_dir(ctx->type),
ctx->obj_uid);
ret = mkdir(tmp, S_IRWXU);
if (ret && errno != EEXIST) {
fprintf(stderr, "mkdir %s failed: %s\n", tmp, strerror(errno));
return ret;
}
return 0;
}
static int bpf_make_custom_path(const struct bpf_elf_ctx *ctx,
const char *todo)
{
char tmp[PATH_MAX], rem[PATH_MAX], *sub;
int ret;
snprintf(tmp, sizeof(tmp), "%s/../", bpf_get_work_dir(ctx->type));
snprintf(rem, sizeof(rem), "%s/", todo);
sub = strtok(rem, "/");
while (sub) {
if (strlen(tmp) + strlen(sub) + 2 > PATH_MAX)
return -EINVAL;
strcat(tmp, sub);
strcat(tmp, "/");
ret = mkdir(tmp, S_IRWXU);
if (ret && errno != EEXIST) {
fprintf(stderr, "mkdir %s failed: %s\n", tmp,
strerror(errno));
return ret;
}
sub = strtok(NULL, "/");
}
return 0;
}
static int bpf_place_pinned(int fd, const char *name,
const struct bpf_elf_ctx *ctx, uint32_t pinning)
{
char pathname[PATH_MAX];
const char *tmp;
int ret = 0;
if (bpf_no_pinning(ctx, pinning) || !bpf_get_work_dir(ctx->type))
return 0;
if (pinning == PIN_OBJECT_NS)
ret = bpf_make_obj_path(ctx);
else if ((tmp = bpf_custom_pinning(ctx, pinning)))
ret = bpf_make_custom_path(ctx, tmp);
if (ret < 0)
return ret;
bpf_make_pathname(pathname, sizeof(pathname), name, ctx, pinning);
return bpf_obj_pin(fd, pathname);
}
static void bpf_prog_report(int fd, const char *section,
const struct bpf_elf_prog *prog,
struct bpf_elf_ctx *ctx)
{
unsigned int insns = prog->size / sizeof(struct bpf_insn);
fprintf(stderr, "\nProg section \'%s\' %s%s (%d)!\n", section,
fd < 0 ? "rejected: " : "loaded",
fd < 0 ? strerror(errno) : "",
fd < 0 ? errno : fd);
fprintf(stderr, " - Type: %u\n", prog->type);
fprintf(stderr, " - Instructions: %u (%u over limit)\n",
insns, insns > BPF_MAXINSNS ? insns - BPF_MAXINSNS : 0);
fprintf(stderr, " - License: %s\n\n", prog->license);
bpf_dump_error(ctx, "Verifier analysis:\n\n");
}
static int bpf_prog_attach(const char *section,
const struct bpf_elf_prog *prog,
struct bpf_elf_ctx *ctx)
{
int tries = 0, fd;
retry:
errno = 0;
fd = bpf_prog_load_dev(prog->type, prog->insns, prog->size,
prog->license, ctx->ifindex,
ctx->log, ctx->log_size);
if (fd < 0 || ctx->verbose) {
/* The verifier log is pretty chatty, sometimes so chatty
* on larger programs, that we could fail to dump everything
* into our buffer. Still, try to give a debuggable error
* log for the user, so enlarge it and re-fail.
*/
if (fd < 0 && (errno == ENOSPC || !ctx->log_size)) {
if (tries++ < 10 && !bpf_log_realloc(ctx))
goto retry;
fprintf(stderr, "Log buffer too small to dump verifier log %zu bytes (%d tries)!\n",
ctx->log_size, tries);
return fd;
}
bpf_prog_report(fd, section, prog, ctx);
}
return fd;
}
static void bpf_map_report(int fd, const char *name,
const struct bpf_elf_map *map,
struct bpf_elf_ctx *ctx, int inner_fd)
{
fprintf(stderr, "Map object \'%s\' %s%s (%d)!\n", name,
fd < 0 ? "rejected: " : "loaded",
fd < 0 ? strerror(errno) : "",
fd < 0 ? errno : fd);
fprintf(stderr, " - Type: %u\n", map->type);
fprintf(stderr, " - Identifier: %u\n", map->id);
fprintf(stderr, " - Pinning: %u\n", map->pinning);
fprintf(stderr, " - Size key: %u\n", map->size_key);
fprintf(stderr, " - Size value: %u\n",
inner_fd ? (int)sizeof(int) : map->size_value);
fprintf(stderr, " - Max elems: %u\n", map->max_elem);
fprintf(stderr, " - Flags: %#x\n\n", map->flags);
}
static int bpf_find_map_id(const struct bpf_elf_ctx *ctx, uint32_t id)
{
int i;
for (i = 0; i < ctx->map_num; i++) {
if (ctx->maps[i].id != id)
continue;
if (ctx->map_fds[i] < 0)
return -EINVAL;
return ctx->map_fds[i];
}
return -ENOENT;
}
static void bpf_report_map_in_map(int outer_fd, uint32_t idx)
{
struct bpf_elf_map outer_map;
int ret;
fprintf(stderr, "Cannot insert map into map! ");
ret = bpf_derive_elf_map_from_fdinfo(outer_fd, &outer_map, NULL);
if (!ret) {
if (idx >= outer_map.max_elem &&
outer_map.type == BPF_MAP_TYPE_ARRAY_OF_MAPS) {
fprintf(stderr, "Outer map has %u elements, index %u is invalid!\n",
outer_map.max_elem, idx);
return;
}
}
fprintf(stderr, "Different map specs used for outer and inner map?\n");
}
static bool bpf_is_map_in_map_type(const struct bpf_elf_map *map)
{
return map->type == BPF_MAP_TYPE_ARRAY_OF_MAPS ||
map->type == BPF_MAP_TYPE_HASH_OF_MAPS;
}
static bool bpf_map_offload_neutral(enum bpf_map_type type)
{
return type == BPF_MAP_TYPE_PERF_EVENT_ARRAY;
}
static int bpf_map_attach(const char *name, struct bpf_elf_ctx *ctx,
const struct bpf_elf_map *map, struct bpf_map_ext *ext,
int *have_map_in_map)
{
int fd, ifindex, ret, map_inner_fd = 0;
bool retried = false;
probe:
fd = bpf_probe_pinned(name, ctx, map->pinning);
if (fd > 0) {
ret = bpf_map_selfcheck_pinned(fd, map, ext,
offsetof(struct bpf_elf_map,
id), ctx->type);
if (ret < 0) {
close(fd);
fprintf(stderr, "Map \'%s\' self-check failed!\n",
name);
return ret;
}
if (ctx->verbose)
fprintf(stderr, "Map \'%s\' loaded as pinned!\n",
name);
return fd;
}
if (have_map_in_map && bpf_is_map_in_map_type(map)) {
(*have_map_in_map)++;
if (map->inner_id)
return 0;
fprintf(stderr, "Map \'%s\' cannot be created since no inner map ID defined!\n",
name);
return -EINVAL;
}
if (!have_map_in_map && bpf_is_map_in_map_type(map)) {
map_inner_fd = bpf_find_map_id(ctx, map->inner_id);
if (map_inner_fd < 0) {
fprintf(stderr, "Map \'%s\' cannot be loaded. Inner map with ID %u not found!\n",
name, map->inner_id);
return -EINVAL;
}
}
ifindex = bpf_map_offload_neutral(map->type) ? 0 : ctx->ifindex;
errno = 0;
fd = bpf_map_create(map->type, map->size_key, map->size_value,
map->max_elem, map->flags, map_inner_fd, ctx->btf_fd,
ifindex, ext->btf_id_key, ext->btf_id_val);
if (fd < 0 || ctx->verbose) {
bpf_map_report(fd, name, map, ctx, map_inner_fd);
if (fd < 0)
return fd;
}
ret = bpf_place_pinned(fd, name, ctx, map->pinning);
if (ret < 0) {
close(fd);
if (!retried && errno == EEXIST) {
retried = true;
goto probe;
}
fprintf(stderr, "Could not pin %s map: %s\n", name,
strerror(errno));
return ret;
}
return fd;
}
static const char *bpf_str_tab_name(const struct bpf_elf_ctx *ctx,
const GElf_Sym *sym)
{
return ctx->str_tab->d_buf + sym->st_name;
}
static int bpf_btf_find(struct bpf_elf_ctx *ctx, const char *name)
{
const struct btf_type *type;
const char *res;
int id;
for (id = 1; id < ctx->btf.types_num; id++) {
type = ctx->btf.types[id];
if (type->name_off >= ctx->btf.hdr->str_len)
continue;
res = &ctx->btf.strings[type->name_off];
if (!strcmp(res, name))
return id;
}
return -ENOENT;
}
static int bpf_btf_find_kv(struct bpf_elf_ctx *ctx, const struct bpf_elf_map *map,
const char *name, uint32_t *id_key, uint32_t *id_val)
{
const struct btf_member *key, *val;
const struct btf_type *type;
char btf_name[512];
const char *res;
int id;
snprintf(btf_name, sizeof(btf_name), "____btf_map_%s", name);
id = bpf_btf_find(ctx, btf_name);
if (id < 0)
return id;
type = ctx->btf.types[id];
if (BTF_INFO_KIND(type->info) != BTF_KIND_STRUCT)
return -EINVAL;
if (BTF_INFO_VLEN(type->info) != 2)
return -EINVAL;
key = ((void *) type) + sizeof(*type);
val = key + 1;
if (!key->type || key->type >= ctx->btf.types_num ||
!val->type || val->type >= ctx->btf.types_num)
return -EINVAL;
if (key->name_off >= ctx->btf.hdr->str_len ||
val->name_off >= ctx->btf.hdr->str_len)
return -EINVAL;
res = &ctx->btf.strings[key->name_off];
if (strcmp(res, "key"))
return -EINVAL;
res = &ctx->btf.strings[val->name_off];
if (strcmp(res, "value"))
return -EINVAL;
*id_key = key->type;
*id_val = val->type;
return 0;
}
static void bpf_btf_annotate(struct bpf_elf_ctx *ctx, int which, const char *name)
{
uint32_t id_key = 0, id_val = 0;
if (!bpf_btf_find_kv(ctx, &ctx->maps[which], name, &id_key, &id_val)) {
ctx->maps_ext[which].btf_id_key = id_key;
ctx->maps_ext[which].btf_id_val = id_val;
}
}
static const char *bpf_map_fetch_name(struct bpf_elf_ctx *ctx, int which)
{
const char *name;
GElf_Sym sym;
int i;
for (i = 0; i < ctx->sym_num; i++) {
int type;
if (gelf_getsym(ctx->sym_tab, i, &sym) != &sym)
continue;
type = GELF_ST_TYPE(sym.st_info);
if (GELF_ST_BIND(sym.st_info) != STB_GLOBAL ||
(type != STT_NOTYPE && type != STT_OBJECT) ||
sym.st_shndx != ctx->sec_maps ||
sym.st_value / ctx->map_len != which)
continue;
name = bpf_str_tab_name(ctx, &sym);
bpf_btf_annotate(ctx, which, name);
return name;
}
return NULL;
}
static int bpf_maps_attach_all(struct bpf_elf_ctx *ctx)
{
int i, j, ret, fd, inner_fd, inner_idx, have_map_in_map = 0;
const char *map_name;
for (i = 0; i < ctx->map_num; i++) {
if (ctx->maps[i].pinning == PIN_OBJECT_NS &&
ctx->noafalg) {
fprintf(stderr, "Missing kernel AF_ALG support for PIN_OBJECT_NS!\n");
return -ENOTSUP;
}
map_name = bpf_map_fetch_name(ctx, i);
if (!map_name)
return -EIO;
fd = bpf_map_attach(map_name, ctx, &ctx->maps[i],
&ctx->maps_ext[i], &have_map_in_map);
if (fd < 0)
return fd;
ctx->map_fds[i] = !fd ? -1 : fd;
}
for (i = 0; have_map_in_map && i < ctx->map_num; i++) {
if (ctx->map_fds[i] >= 0)
continue;
map_name = bpf_map_fetch_name(ctx, i);
if (!map_name)
return -EIO;
fd = bpf_map_attach(map_name, ctx, &ctx->maps[i],
&ctx->maps_ext[i], NULL);
if (fd < 0)
return fd;
ctx->map_fds[i] = fd;
}
for (i = 0; have_map_in_map && i < ctx->map_num; i++) {
if (!ctx->maps[i].id ||
ctx->maps[i].inner_id ||
ctx->maps[i].inner_idx == -1)
continue;
inner_fd = ctx->map_fds[i];
inner_idx = ctx->maps[i].inner_idx;
for (j = 0; j < ctx->map_num; j++) {
if (!bpf_is_map_in_map_type(&ctx->maps[j]))
continue;
if (ctx->maps[j].inner_id != ctx->maps[i].id)
continue;
ret = bpf_map_update(ctx->map_fds[j], &inner_idx,
&inner_fd, BPF_ANY);
if (ret < 0) {
bpf_report_map_in_map(ctx->map_fds[j],
inner_idx);
return ret;
}
}
}
return 0;
}
static int bpf_map_num_sym(struct bpf_elf_ctx *ctx)
{
int i, num = 0;
GElf_Sym sym;
for (i = 0; i < ctx->sym_num; i++) {
int type;
if (gelf_getsym(ctx->sym_tab, i, &sym) != &sym)
continue;
type = GELF_ST_TYPE(sym.st_info);
if (GELF_ST_BIND(sym.st_info) != STB_GLOBAL ||
(type != STT_NOTYPE && type != STT_OBJECT) ||
sym.st_shndx != ctx->sec_maps)
continue;
num++;
}
return num;
}
static int bpf_fill_section_data(struct bpf_elf_ctx *ctx, int section,
struct bpf_elf_sec_data *data)
{
Elf_Data *sec_edata;
GElf_Shdr sec_hdr;
Elf_Scn *sec_fd;
char *sec_name;
memset(data, 0, sizeof(*data));
sec_fd = elf_getscn(ctx->elf_fd, section);
if (!sec_fd)
return -EINVAL;
if (gelf_getshdr(sec_fd, &sec_hdr) != &sec_hdr)
return -EIO;
sec_name = elf_strptr(ctx->elf_fd, ctx->elf_hdr.e_shstrndx,
sec_hdr.sh_name);
if (!sec_name || !sec_hdr.sh_size)
return -ENOENT;
sec_edata = elf_getdata(sec_fd, NULL);
if (!sec_edata || elf_getdata(sec_fd, sec_edata))
return -EIO;
memcpy(&data->sec_hdr, &sec_hdr, sizeof(sec_hdr));
data->sec_name = sec_name;
data->sec_data = sec_edata;
return 0;
}
struct bpf_elf_map_min {
__u32 type;
__u32 size_key;
__u32 size_value;
__u32 max_elem;
};
static int bpf_fetch_maps_begin(struct bpf_elf_ctx *ctx, int section,
struct bpf_elf_sec_data *data)
{
ctx->map_num = data->sec_data->d_size;
ctx->sec_maps = section;
ctx->sec_done[section] = true;
if (ctx->map_num > sizeof(ctx->maps)) {
fprintf(stderr, "Too many BPF maps in ELF section!\n");
return -ENOMEM;
}
memcpy(ctx->maps, data->sec_data->d_buf, ctx->map_num);
return 0;
}
static int bpf_map_verify_all_offs(struct bpf_elf_ctx *ctx, int end)
{
GElf_Sym sym;
int off, i;
for (off = 0; off < end; off += ctx->map_len) {
/* Order doesn't need to be linear here, hence we walk
* the table again.
*/
for (i = 0; i < ctx->sym_num; i++) {
int type;
if (gelf_getsym(ctx->sym_tab, i, &sym) != &sym)
continue;
type = GELF_ST_TYPE(sym.st_info);
if (GELF_ST_BIND(sym.st_info) != STB_GLOBAL ||
(type != STT_NOTYPE && type != STT_OBJECT) ||
sym.st_shndx != ctx->sec_maps)
continue;
if (sym.st_value == off)
break;
if (i == ctx->sym_num - 1)
return -1;
}
}
return off == end ? 0 : -1;
}
static int bpf_fetch_maps_end(struct bpf_elf_ctx *ctx)
{
struct bpf_elf_map fixup[ARRAY_SIZE(ctx->maps)] = {};
int i, sym_num = bpf_map_num_sym(ctx);
__u8 *buff;
if (sym_num == 0 || sym_num > ARRAY_SIZE(ctx->maps)) {
fprintf(stderr, "%u maps not supported in current map section!\n",
sym_num);
return -EINVAL;
}
if (ctx->map_num % sym_num != 0 ||
ctx->map_num % sizeof(__u32) != 0) {
fprintf(stderr, "Number BPF map symbols are not multiple of struct bpf_elf_map!\n");
return -EINVAL;
}
ctx->map_len = ctx->map_num / sym_num;
if (bpf_map_verify_all_offs(ctx, ctx->map_num)) {
fprintf(stderr, "Different struct bpf_elf_map in use!\n");
return -EINVAL;
}
if (ctx->map_len == sizeof(struct bpf_elf_map)) {
ctx->map_num = sym_num;
return 0;
} else if (ctx->map_len > sizeof(struct bpf_elf_map)) {
fprintf(stderr, "struct bpf_elf_map not supported, coming from future version?\n");
return -EINVAL;
} else if (ctx->map_len < sizeof(struct bpf_elf_map_min)) {
fprintf(stderr, "struct bpf_elf_map too small, not supported!\n");
return -EINVAL;
}
ctx->map_num = sym_num;
for (i = 0, buff = (void *)ctx->maps; i < ctx->map_num;
i++, buff += ctx->map_len) {
/* The fixup leaves the rest of the members as zero, which
* is fine currently, but option exist to set some other
* default value as well when needed in future.
*/
memcpy(&fixup[i], buff, ctx->map_len);
}
memcpy(ctx->maps, fixup, sizeof(fixup));
if (ctx->verbose)
printf("%zu bytes struct bpf_elf_map fixup performed due to size mismatch!\n",
sizeof(struct bpf_elf_map) - ctx->map_len);
return 0;
}
static int bpf_fetch_license(struct bpf_elf_ctx *ctx, int section,
struct bpf_elf_sec_data *data)
{
if (data->sec_data->d_size > sizeof(ctx->license))
return -ENOMEM;
memcpy(ctx->license, data->sec_data->d_buf, data->sec_data->d_size);
ctx->sec_done[section] = true;
return 0;
}
static int bpf_fetch_symtab(struct bpf_elf_ctx *ctx, int section,
struct bpf_elf_sec_data *data)
{
ctx->sym_tab = data->sec_data;
ctx->sym_num = data->sec_hdr.sh_size / data->sec_hdr.sh_entsize;
ctx->sec_done[section] = true;
return 0;
}
static int bpf_fetch_strtab(struct bpf_elf_ctx *ctx, int section,
struct bpf_elf_sec_data *data)
{
ctx->str_tab = data->sec_data;
ctx->sec_done[section] = true;
return 0;
}
static int bpf_fetch_text(struct bpf_elf_ctx *ctx, int section,
struct bpf_elf_sec_data *data)
{
ctx->sec_text = section;
ctx->sec_done[section] = true;
return 0;
}
static void bpf_btf_report(int fd, struct bpf_elf_ctx *ctx)
{
fprintf(stderr, "\nBTF debug data section \'.BTF\' %s%s (%d)!\n",
fd < 0 ? "rejected: " : "loaded",
fd < 0 ? strerror(errno) : "",
fd < 0 ? errno : fd);
fprintf(stderr, " - Length: %zu\n", ctx->btf_data->d_size);
bpf_dump_error(ctx, "Verifier analysis:\n\n");
}
static int bpf_btf_attach(struct bpf_elf_ctx *ctx)
{
int tries = 0, fd;
retry:
errno = 0;
fd = bpf_btf_load(ctx->btf_data->d_buf, ctx->btf_data->d_size,
ctx->log, ctx->log_size);
if (fd < 0 || ctx->verbose) {
if (fd < 0 && (errno == ENOSPC || !ctx->log_size)) {
if (tries++ < 10 && !bpf_log_realloc(ctx))
goto retry;
fprintf(stderr, "Log buffer too small to dump verifier log %zu bytes (%d tries)!\n",
ctx->log_size, tries);
return fd;
}
if (bpf_log_has_data(ctx))
bpf_btf_report(fd, ctx);
}
return fd;
}
static int bpf_fetch_btf_begin(struct bpf_elf_ctx *ctx, int section,
struct bpf_elf_sec_data *data)
{
ctx->btf_data = data->sec_data;
ctx->sec_btf = section;
ctx->sec_done[section] = true;
return 0;
}
static int bpf_btf_check_header(struct bpf_elf_ctx *ctx)
{
const struct btf_header *hdr = ctx->btf_data->d_buf;
const char *str_start, *str_end;
unsigned int data_len;
if (hdr->magic != BTF_MAGIC) {
fprintf(stderr, "Object has wrong BTF magic: %x, expected: %x!\n",
hdr->magic, BTF_MAGIC);
return -EINVAL;
}
if (hdr->version != BTF_VERSION) {
fprintf(stderr, "Object has wrong BTF version: %u, expected: %u!\n",
hdr->version, BTF_VERSION);
return -EINVAL;
}
if (hdr->flags) {
fprintf(stderr, "Object has unsupported BTF flags %x!\n",
hdr->flags);
return -EINVAL;
}
data_len = ctx->btf_data->d_size - sizeof(*hdr);
if (data_len < hdr->type_off ||
data_len < hdr->str_off ||
data_len < hdr->type_len + hdr->str_len ||
hdr->type_off >= hdr->str_off ||
hdr->type_off + hdr->type_len != hdr->str_off ||
hdr->str_off + hdr->str_len != data_len ||
(hdr->type_off & (sizeof(uint32_t) - 1))) {
fprintf(stderr, "Object has malformed BTF data!\n");
return -EINVAL;
}
ctx->btf.hdr = hdr;
ctx->btf.raw = hdr + 1;
str_start = ctx->btf.raw + hdr->str_off;
str_end = str_start + hdr->str_len;
if (!hdr->str_len ||
hdr->str_len - 1 > BTF_MAX_NAME_OFFSET ||
str_start[0] || str_end[-1]) {
fprintf(stderr, "Object has malformed BTF string data!\n");
return -EINVAL;
}
ctx->btf.strings = str_start;
return 0;
}
static int bpf_btf_register_type(struct bpf_elf_ctx *ctx,
const struct btf_type *type)
{
int cur = ctx->btf.types_num, num = cur + 1;
const struct btf_type **types;
types = realloc(ctx->btf.types, num * sizeof(type));
if (!types) {
free(ctx->btf.types);
ctx->btf.types = NULL;
ctx->btf.types_num = 0;
return -ENOMEM;
}
ctx->btf.types = types;
ctx->btf.types[cur] = type;
ctx->btf.types_num = num;
return 0;
}
static struct btf_type btf_type_void;
static int bpf_btf_prep_type_data(struct bpf_elf_ctx *ctx)
{
const void *type_cur = ctx->btf.raw + ctx->btf.hdr->type_off;
const void *type_end = ctx->btf.raw + ctx->btf.hdr->str_off;
const struct btf_type *type;
uint16_t var_len;
int ret, kind;
ret = bpf_btf_register_type(ctx, &btf_type_void);
if (ret < 0)
return ret;
while (type_cur < type_end) {
type = type_cur;
type_cur += sizeof(*type);
var_len = BTF_INFO_VLEN(type->info);
kind = BTF_INFO_KIND(type->info);
switch (kind) {
case BTF_KIND_INT:
type_cur += sizeof(int);
break;
case BTF_KIND_ARRAY:
type_cur += sizeof(struct btf_array);
break;
case BTF_KIND_STRUCT:
case BTF_KIND_UNION:
type_cur += var_len * sizeof(struct btf_member);
break;
case BTF_KIND_ENUM:
type_cur += var_len * sizeof(struct btf_enum);
break;
case BTF_KIND_FUNC_PROTO:
type_cur += var_len * sizeof(struct btf_param);
break;
case BTF_KIND_TYPEDEF:
case BTF_KIND_PTR:
case BTF_KIND_FWD:
case BTF_KIND_VOLATILE:
case BTF_KIND_CONST:
case BTF_KIND_RESTRICT:
case BTF_KIND_FUNC:
break;
default:
fprintf(stderr, "Object has unknown BTF type: %u!\n", kind);
return -EINVAL;
}
ret = bpf_btf_register_type(ctx, type);
if (ret < 0)
return ret;
}
return 0;
}
static int bpf_btf_prep_data(struct bpf_elf_ctx *ctx)
{
int ret = bpf_btf_check_header(ctx);
if (!ret)
return bpf_btf_prep_type_data(ctx);
return ret;
}
static void bpf_fetch_btf_end(struct bpf_elf_ctx *ctx)
{
int fd = bpf_btf_attach(ctx);
if (fd < 0)
return;
ctx->btf_fd = fd;
if (bpf_btf_prep_data(ctx) < 0) {
close(ctx->btf_fd);
ctx->btf_fd = 0;
}
}
static bool bpf_has_map_data(const struct bpf_elf_ctx *ctx)
{
return ctx->sym_tab && ctx->str_tab && ctx->sec_maps;
}
static bool bpf_has_btf_data(const struct bpf_elf_ctx *ctx)
{
return ctx->sec_btf;
}
static bool bpf_has_call_data(const struct bpf_elf_ctx *ctx)
{
return ctx->sec_text;
}
static int bpf_fetch_ancillary(struct bpf_elf_ctx *ctx, bool check_text_sec)
{
struct bpf_elf_sec_data data;
int i, ret = -1;
for (i = 1; i < ctx->elf_hdr.e_shnum; i++) {
ret = bpf_fill_section_data(ctx, i, &data);
if (ret < 0)
continue;
if (data.sec_hdr.sh_type == SHT_PROGBITS &&
!strcmp(data.sec_name, ELF_SECTION_MAPS))
ret = bpf_fetch_maps_begin(ctx, i, &data);
else if (data.sec_hdr.sh_type == SHT_PROGBITS &&
!strcmp(data.sec_name, ELF_SECTION_LICENSE))
ret = bpf_fetch_license(ctx, i, &data);
else if (data.sec_hdr.sh_type == SHT_PROGBITS &&
(data.sec_hdr.sh_flags & SHF_EXECINSTR) &&
!strcmp(data.sec_name, ".text") &&
check_text_sec)
ret = bpf_fetch_text(ctx, i, &data);
else if (data.sec_hdr.sh_type == SHT_SYMTAB &&
!strcmp(data.sec_name, ".symtab"))
ret = bpf_fetch_symtab(ctx, i, &data);
else if (data.sec_hdr.sh_type == SHT_STRTAB &&
!strcmp(data.sec_name, ".strtab"))
ret = bpf_fetch_strtab(ctx, i, &data);
else if (data.sec_hdr.sh_type == SHT_PROGBITS &&
!strcmp(data.sec_name, ".BTF"))
ret = bpf_fetch_btf_begin(ctx, i, &data);
if (ret < 0) {
fprintf(stderr, "Error parsing section %d! Perhaps check with readelf -a?\n",
i);
return ret;
}
}
if (bpf_has_btf_data(ctx))
bpf_fetch_btf_end(ctx);
if (bpf_has_map_data(ctx)) {
ret = bpf_fetch_maps_end(ctx);
if (ret < 0) {
fprintf(stderr, "Error fixing up map structure, incompatible struct bpf_elf_map used?\n");
return ret;
}
ret = bpf_maps_attach_all(ctx);
if (ret < 0) {
fprintf(stderr, "Error loading maps into kernel!\n");
return ret;
}
}
return ret;
}
static int bpf_fetch_prog(struct bpf_elf_ctx *ctx, const char *section,
bool *sseen)
{
struct bpf_elf_sec_data data;
struct bpf_elf_prog prog;
int ret, i, fd = -1;
for (i = 1; i < ctx->elf_hdr.e_shnum; i++) {
if (ctx->sec_done[i])
continue;
ret = bpf_fill_section_data(ctx, i, &data);
if (ret < 0 ||
!(data.sec_hdr.sh_type == SHT_PROGBITS &&
(data.sec_hdr.sh_flags & SHF_EXECINSTR) &&
!strcmp(data.sec_name, section)))
continue;
*sseen = true;
memset(&prog, 0, sizeof(prog));
prog.type = ctx->type;
prog.license = ctx->license;
prog.size = data.sec_data->d_size;
prog.insns_num = prog.size / sizeof(struct bpf_insn);
prog.insns = data.sec_data->d_buf;
fd = bpf_prog_attach(section, &prog, ctx);
if (fd < 0)
return fd;
ctx->sec_done[i] = true;
break;
}
return fd;
}
struct bpf_relo_props {
struct bpf_tail_call {
unsigned int total;
unsigned int jited;
} tc;
int main_num;
};
static int bpf_apply_relo_map(struct bpf_elf_ctx *ctx, struct bpf_elf_prog *prog,
GElf_Rel *relo, GElf_Sym *sym,
struct bpf_relo_props *props)
{
unsigned int insn_off = relo->r_offset / sizeof(struct bpf_insn);
unsigned int map_idx = sym->st_value / ctx->map_len;
if (insn_off >= prog->insns_num)
return -EINVAL;
if (prog->insns[insn_off].code != (BPF_LD | BPF_IMM | BPF_DW)) {
fprintf(stderr, "ELF contains relo data for non ld64 instruction at offset %u! Compiler bug?!\n",
insn_off);
return -EINVAL;
}
if (map_idx >= ARRAY_SIZE(ctx->map_fds))
return -EINVAL;
if (!ctx->map_fds[map_idx])
return -EINVAL;
if (ctx->maps[map_idx].type == BPF_MAP_TYPE_PROG_ARRAY) {
props->tc.total++;
if (ctx->maps_ext[map_idx].owner.jited ||
(ctx->maps_ext[map_idx].owner.type == 0 &&
ctx->cfg.jit_enabled))
props->tc.jited++;
}
prog->insns[insn_off].src_reg = BPF_PSEUDO_MAP_FD;
prog->insns[insn_off].imm = ctx->map_fds[map_idx];
return 0;
}
static int bpf_apply_relo_call(struct bpf_elf_ctx *ctx, struct bpf_elf_prog *prog,
GElf_Rel *relo, GElf_Sym *sym,
struct bpf_relo_props *props)
{
unsigned int insn_off = relo->r_offset / sizeof(struct bpf_insn);
struct bpf_elf_prog *prog_text = &ctx->prog_text;
if (insn_off >= prog->insns_num)
return -EINVAL;
if (prog->insns[insn_off].code != (BPF_JMP | BPF_CALL) &&
prog->insns[insn_off].src_reg != BPF_PSEUDO_CALL) {
fprintf(stderr, "ELF contains relo data for non call instruction at offset %u! Compiler bug?!\n",
insn_off);
return -EINVAL;
}
if (!props->main_num) {
struct bpf_insn *insns = realloc(prog->insns,
prog->size + prog_text->size);
if (!insns)
return -ENOMEM;
memcpy(insns + prog->insns_num, prog_text->insns,
prog_text->size);
props->main_num = prog->insns_num;
prog->insns = insns;
prog->insns_num += prog_text->insns_num;
prog->size += prog_text->size;
}
prog->insns[insn_off].imm += props->main_num - insn_off;
return 0;
}
static int bpf_apply_relo_data(struct bpf_elf_ctx *ctx,
struct bpf_elf_sec_data *data_relo,
struct bpf_elf_prog *prog,
struct bpf_relo_props *props)
{
GElf_Shdr *rhdr = &data_relo->sec_hdr;
int relo_ent, relo_num = rhdr->sh_size / rhdr->sh_entsize;
for (relo_ent = 0; relo_ent < relo_num; relo_ent++) {
GElf_Rel relo;
GElf_Sym sym;
int ret = -EIO;
if (gelf_getrel(data_relo->sec_data, relo_ent, &relo) != &relo)
return -EIO;
if (gelf_getsym(ctx->sym_tab, GELF_R_SYM(relo.r_info), &sym) != &sym)
return -EIO;
if (sym.st_shndx == ctx->sec_maps)
ret = bpf_apply_relo_map(ctx, prog, &relo, &sym, props);
else if (sym.st_shndx == ctx->sec_text)
ret = bpf_apply_relo_call(ctx, prog, &relo, &sym, props);
else
fprintf(stderr, "ELF contains non-{map,call} related relo data in entry %u pointing to section %u! Compiler bug?!\n",
relo_ent, sym.st_shndx);
if (ret < 0)
return ret;
}
return 0;
}
static int bpf_fetch_prog_relo(struct bpf_elf_ctx *ctx, const char *section,
bool *lderr, bool *sseen, struct bpf_elf_prog *prog)
{
struct bpf_elf_sec_data data_relo, data_insn;
int ret, idx, i, fd = -1;
for (i = 1; i < ctx->elf_hdr.e_shnum; i++) {
struct bpf_relo_props props = {};
ret = bpf_fill_section_data(ctx, i, &data_relo);
if (ret < 0 || data_relo.sec_hdr.sh_type != SHT_REL)
continue;
idx = data_relo.sec_hdr.sh_info;
ret = bpf_fill_section_data(ctx, idx, &data_insn);
if (ret < 0 ||
!(data_insn.sec_hdr.sh_type == SHT_PROGBITS &&
(data_insn.sec_hdr.sh_flags & SHF_EXECINSTR) &&
!strcmp(data_insn.sec_name, section)))
continue;
if (sseen)
*sseen = true;
memset(prog, 0, sizeof(*prog));
prog->type = ctx->type;
prog->license = ctx->license;
prog->size = data_insn.sec_data->d_size;
prog->insns_num = prog->size / sizeof(struct bpf_insn);
prog->insns = malloc(prog->size);
if (!prog->insns) {
*lderr = true;
return -ENOMEM;
}
memcpy(prog->insns, data_insn.sec_data->d_buf, prog->size);
ret = bpf_apply_relo_data(ctx, &data_relo, prog, &props);
if (ret < 0) {
*lderr = true;
if (ctx->sec_text != idx)
free(prog->insns);
return ret;
}
if (ctx->sec_text == idx) {
fd = 0;
goto out;
}
fd = bpf_prog_attach(section, prog, ctx);
free(prog->insns);
if (fd < 0) {
*lderr = true;
if (props.tc.total) {
if (ctx->cfg.jit_enabled &&
props.tc.total != props.tc.jited)
fprintf(stderr, "JIT enabled, but only %u/%u tail call maps in the program have JITed owner!\n",
props.tc.jited, props.tc.total);
if (!ctx->cfg.jit_enabled &&
props.tc.jited)
fprintf(stderr, "JIT disabled, but %u/%u tail call maps in the program have JITed owner!\n",
props.tc.jited, props.tc.total);
}
return fd;
}
out:
ctx->sec_done[i] = true;
ctx->sec_done[idx] = true;
break;
}
return fd;
}
static int bpf_fetch_prog_sec(struct bpf_elf_ctx *ctx, const char *section)
{
bool lderr = false, sseen = false;
struct bpf_elf_prog prog;
int ret = -1;
if (bpf_has_call_data(ctx)) {
ret = bpf_fetch_prog_relo(ctx, ".text", &lderr, NULL,
&ctx->prog_text);
if (ret < 0)
return ret;
}
if (bpf_has_map_data(ctx) || bpf_has_call_data(ctx))
ret = bpf_fetch_prog_relo(ctx, section, &lderr, &sseen, &prog);
if (ret < 0 && !lderr)
ret = bpf_fetch_prog(ctx, section, &sseen);
if (ret < 0 && !sseen)
fprintf(stderr, "Program section \'%s\' not found in ELF file!\n",
section);
return ret;
}
static int bpf_find_map_by_id(struct bpf_elf_ctx *ctx, uint32_t id)
{
int i;
for (i = 0; i < ARRAY_SIZE(ctx->map_fds); i++)
if (ctx->map_fds[i] && ctx->maps[i].id == id &&
ctx->maps[i].type == BPF_MAP_TYPE_PROG_ARRAY)
return i;
return -1;
}
struct bpf_jited_aux {
int prog_fd;
int map_fd;
struct bpf_prog_data prog;
struct bpf_map_ext map;
};
static int bpf_derive_prog_from_fdinfo(int fd, struct bpf_prog_data *prog)
{
char file[PATH_MAX], buff[4096];
unsigned int val;
FILE *fp;
snprintf(file, sizeof(file), "/proc/%d/fdinfo/%d", getpid(), fd);
memset(prog, 0, sizeof(*prog));
fp = fopen(file, "r");
if (!fp) {
fprintf(stderr, "No procfs support?!\n");
return -EIO;
}
while (fgets(buff, sizeof(buff), fp)) {
if (sscanf(buff, "prog_type:\t%u", &val) == 1)
prog->type = val;
else if (sscanf(buff, "prog_jited:\t%u", &val) == 1)
prog->jited = val;
}
fclose(fp);
return 0;
}
static int bpf_tail_call_get_aux(struct bpf_jited_aux *aux)
{
struct bpf_elf_map tmp;
int ret;
ret = bpf_derive_elf_map_from_fdinfo(aux->map_fd, &tmp, &aux->map);
if (!ret)
ret = bpf_derive_prog_from_fdinfo(aux->prog_fd, &aux->prog);
return ret;
}
static int bpf_fill_prog_arrays(struct bpf_elf_ctx *ctx)
{
struct bpf_elf_sec_data data;
uint32_t map_id, key_id;
int fd, i, ret, idx;
for (i = 1; i < ctx->elf_hdr.e_shnum; i++) {
if (ctx->sec_done[i])
continue;
ret = bpf_fill_section_data(ctx, i, &data);
if (ret < 0)
continue;
ret = sscanf(data.sec_name, "%i/%i", &map_id, &key_id);
if (ret != 2)
continue;
idx = bpf_find_map_by_id(ctx, map_id);
if (idx < 0)
continue;
fd = bpf_fetch_prog_sec(ctx, data.sec_name);
if (fd < 0)
return -EIO;
ret = bpf_map_update(ctx->map_fds[idx], &key_id,
&fd, BPF_ANY);
if (ret < 0) {
struct bpf_jited_aux aux = {};
ret = -errno;
if (errno == E2BIG) {
fprintf(stderr, "Tail call key %u for map %u out of bounds?\n",
key_id, map_id);
return ret;
}
aux.map_fd = ctx->map_fds[idx];
aux.prog_fd = fd;
if (bpf_tail_call_get_aux(&aux))
return ret;
if (!aux.map.owner.type)
return ret;
if (aux.prog.type != aux.map.owner.type)
fprintf(stderr, "Tail call map owned by prog type %u, but prog type is %u!\n",
aux.map.owner.type, aux.prog.type);
if (aux.prog.jited != aux.map.owner.jited)
fprintf(stderr, "Tail call map %s jited, but prog %s!\n",
aux.map.owner.jited ? "is" : "not",
aux.prog.jited ? "is" : "not");
return ret;
}
ctx->sec_done[i] = true;
}
return 0;
}
static void bpf_save_finfo(struct bpf_elf_ctx *ctx)
{
struct stat st;
int ret;
memset(&ctx->stat, 0, sizeof(ctx->stat));
ret = fstat(ctx->obj_fd, &st);
if (ret < 0) {
fprintf(stderr, "Stat of elf file failed: %s\n",
strerror(errno));
return;
}
ctx->stat.st_dev = st.st_dev;
ctx->stat.st_ino = st.st_ino;
}
static int bpf_read_pin_mapping(FILE *fp, uint32_t *id, char *path)
{
char buff[PATH_MAX];
while (fgets(buff, sizeof(buff), fp)) {
char *ptr = buff;
while (*ptr == ' ' || *ptr == '\t')
ptr++;
if (*ptr == '#' || *ptr == '\n' || *ptr == 0)
continue;
if (sscanf(ptr, "%i %s\n", id, path) != 2 &&
sscanf(ptr, "%i %s #", id, path) != 2) {
strcpy(path, ptr);
return -1;
}
return 1;
}
return 0;
}
static bool bpf_pinning_reserved(uint32_t pinning)
{
switch (pinning) {
case PIN_NONE:
case PIN_OBJECT_NS:
case PIN_GLOBAL_NS:
return true;
default:
return false;
}
}
static void bpf_hash_init(struct bpf_elf_ctx *ctx, const char *db_file)
{
struct bpf_hash_entry *entry;
char subpath[PATH_MAX] = {};
uint32_t pinning;
FILE *fp;
int ret;
fp = fopen(db_file, "r");
if (!fp)
return;
while ((ret = bpf_read_pin_mapping(fp, &pinning, subpath))) {
if (ret == -1) {
fprintf(stderr, "Database %s is corrupted at: %s\n",
db_file, subpath);
fclose(fp);
return;
}
if (bpf_pinning_reserved(pinning)) {
fprintf(stderr, "Database %s, id %u is reserved - ignoring!\n",
db_file, pinning);
continue;
}
entry = malloc(sizeof(*entry));
if (!entry) {
fprintf(stderr, "No memory left for db entry!\n");
continue;
}
entry->pinning = pinning;
entry->subpath = strdup(subpath);
if (!entry->subpath) {
fprintf(stderr, "No memory left for db entry!\n");
free(entry);
continue;
}
entry->next = ctx->ht[pinning & (ARRAY_SIZE(ctx->ht) - 1)];
ctx->ht[pinning & (ARRAY_SIZE(ctx->ht) - 1)] = entry;
}
fclose(fp);
}
static void bpf_hash_destroy(struct bpf_elf_ctx *ctx)
{
struct bpf_hash_entry *entry;
int i;
for (i = 0; i < ARRAY_SIZE(ctx->ht); i++) {
while ((entry = ctx->ht[i]) != NULL) {
ctx->ht[i] = entry->next;
free((char *)entry->subpath);
free(entry);
}
}
}
static int bpf_elf_check_ehdr(const struct bpf_elf_ctx *ctx)
{
if (ctx->elf_hdr.e_type != ET_REL ||
(ctx->elf_hdr.e_machine != EM_NONE &&
ctx->elf_hdr.e_machine != EM_BPF) ||
ctx->elf_hdr.e_version != EV_CURRENT) {
fprintf(stderr, "ELF format error, ELF file not for eBPF?\n");
return -EINVAL;
}
switch (ctx->elf_hdr.e_ident[EI_DATA]) {
default:
fprintf(stderr, "ELF format error, wrong endianness info?\n");
return -EINVAL;
case ELFDATA2LSB:
if (htons(1) == 1) {
fprintf(stderr,
"We are big endian, eBPF object is little endian!\n");
return -EIO;
}
break;
case ELFDATA2MSB:
if (htons(1) != 1) {
fprintf(stderr,
"We are little endian, eBPF object is big endian!\n");
return -EIO;
}
break;
}
return 0;
}
static void bpf_get_cfg(struct bpf_elf_ctx *ctx)
{
static const char *path_jit = "/proc/sys/net/core/bpf_jit_enable";
int fd;
fd = open(path_jit, O_RDONLY);
if (fd > 0) {
char tmp[16] = {};
if (read(fd, tmp, sizeof(tmp)) > 0)
ctx->cfg.jit_enabled = atoi(tmp);
close(fd);
}
}
static int bpf_elf_ctx_init(struct bpf_elf_ctx *ctx, const char *pathname,
enum bpf_prog_type type, __u32 ifindex,
bool verbose)
{
uint8_t tmp[20];
int ret;
if (elf_version(EV_CURRENT) == EV_NONE)
return -EINVAL;
bpf_init_env();
memset(ctx, 0, sizeof(*ctx));
bpf_get_cfg(ctx);
ret = bpf_obj_hash(pathname, tmp, sizeof(tmp));
if (ret)
ctx->noafalg = true;
else
hexstring_n2a(tmp, sizeof(tmp), ctx->obj_uid,
sizeof(ctx->obj_uid));
ctx->verbose = verbose;
ctx->type = type;
ctx->ifindex = ifindex;
ctx->obj_fd = open(pathname, O_RDONLY);
if (ctx->obj_fd < 0)
return ctx->obj_fd;
ctx->elf_fd = elf_begin(ctx->obj_fd, ELF_C_READ, NULL);
if (!ctx->elf_fd) {
ret = -EINVAL;
goto out_fd;
}
if (elf_kind(ctx->elf_fd) != ELF_K_ELF) {
ret = -EINVAL;
goto out_fd;
}
if (gelf_getehdr(ctx->elf_fd, &ctx->elf_hdr) !=
&ctx->elf_hdr) {
ret = -EIO;
goto out_elf;
}
ret = bpf_elf_check_ehdr(ctx);
if (ret < 0)
goto out_elf;
ctx->sec_done = calloc(ctx->elf_hdr.e_shnum,
sizeof(*(ctx->sec_done)));
if (!ctx->sec_done) {
ret = -ENOMEM;
goto out_elf;
}
if (ctx->verbose && bpf_log_realloc(ctx)) {
ret = -ENOMEM;
goto out_free;
}
bpf_save_finfo(ctx);
bpf_hash_init(ctx, CONFDIR "/bpf_pinning");
return 0;
out_free:
free(ctx->sec_done);
out_elf:
elf_end(ctx->elf_fd);
out_fd:
close(ctx->obj_fd);
return ret;
}
static int bpf_maps_count(struct bpf_elf_ctx *ctx)
{
int i, count = 0;
for (i = 0; i < ARRAY_SIZE(ctx->map_fds); i++) {
if (!ctx->map_fds[i])
break;
count++;
}
return count;
}
static void bpf_maps_teardown(struct bpf_elf_ctx *ctx)
{
int i;
for (i = 0; i < ARRAY_SIZE(ctx->map_fds); i++) {
if (ctx->map_fds[i])
close(ctx->map_fds[i]);
}
if (ctx->btf_fd)
close(ctx->btf_fd);
free(ctx->btf.types);
}
static void bpf_elf_ctx_destroy(struct bpf_elf_ctx *ctx, bool failure)
{
if (failure)
bpf_maps_teardown(ctx);
bpf_hash_destroy(ctx);
free(ctx->prog_text.insns);
free(ctx->sec_done);
free(ctx->log);
elf_end(ctx->elf_fd);
close(ctx->obj_fd);
}
static struct bpf_elf_ctx __ctx;
static int bpf_obj_open(const char *pathname, enum bpf_prog_type type,
const char *section, __u32 ifindex, bool verbose)
{
struct bpf_elf_ctx *ctx = &__ctx;
int fd = 0, ret;
ret = bpf_elf_ctx_init(ctx, pathname, type, ifindex, verbose);
if (ret < 0) {
fprintf(stderr, "Cannot initialize ELF context!\n");
return ret;
}
ret = bpf_fetch_ancillary(ctx, strcmp(section, ".text"));
if (ret < 0) {
fprintf(stderr, "Error fetching ELF ancillary data!\n");
goto out;
}
fd = bpf_fetch_prog_sec(ctx, section);
if (fd < 0) {
fprintf(stderr, "Error fetching program/map!\n");
ret = fd;
goto out;
}
ret = bpf_fill_prog_arrays(ctx);
if (ret < 0)
fprintf(stderr, "Error filling program arrays!\n");
out:
bpf_elf_ctx_destroy(ctx, ret < 0);
if (ret < 0) {
if (fd)
close(fd);
return ret;
}
return fd;
}
static int
bpf_map_set_send(int fd, struct sockaddr_un *addr, unsigned int addr_len,
const struct bpf_map_data *aux, unsigned int entries)
{
struct bpf_map_set_msg msg = {
.aux.uds_ver = BPF_SCM_AUX_VER,
.aux.num_ent = entries,
};
int *cmsg_buf, min_fd;
char *amsg_buf;
int i;
strlcpy(msg.aux.obj_name, aux->obj, sizeof(msg.aux.obj_name));
memcpy(&msg.aux.obj_st, aux->st, sizeof(msg.aux.obj_st));
cmsg_buf = bpf_map_set_init(&msg, addr, addr_len);
amsg_buf = (char *)msg.aux.ent;
for (i = 0; i < entries; i += min_fd) {
int ret;
min_fd = min(BPF_SCM_MAX_FDS * 1U, entries - i);
bpf_map_set_init_single(&msg, min_fd);
memcpy(cmsg_buf, &aux->fds[i], sizeof(aux->fds[0]) * min_fd);
memcpy(amsg_buf, &aux->ent[i], sizeof(aux->ent[0]) * min_fd);
ret = sendmsg(fd, &msg.hdr, 0);
if (ret <= 0)
return ret ? : -1;
}
return 0;
}
static int
bpf_map_set_recv(int fd, int *fds, struct bpf_map_aux *aux,
unsigned int entries)
{
struct bpf_map_set_msg msg;
int *cmsg_buf, min_fd;
char *amsg_buf, *mmsg_buf;
unsigned int needed = 1;
int i;
cmsg_buf = bpf_map_set_init(&msg, NULL, 0);
amsg_buf = (char *)msg.aux.ent;
mmsg_buf = (char *)&msg.aux;
for (i = 0; i < min(entries, needed); i += min_fd) {
struct cmsghdr *cmsg;
int ret;
min_fd = min(entries, entries - i);
bpf_map_set_init_single(&msg, min_fd);
ret = recvmsg(fd, &msg.hdr, 0);
if (ret <= 0)
return ret ? : -1;
cmsg = CMSG_FIRSTHDR(&msg.hdr);
if (!cmsg || cmsg->cmsg_type != SCM_RIGHTS)
return -EINVAL;
if (msg.hdr.msg_flags & MSG_CTRUNC)
return -EIO;
if (msg.aux.uds_ver != BPF_SCM_AUX_VER)
return -ENOSYS;
min_fd = (cmsg->cmsg_len - sizeof(*cmsg)) / sizeof(fd);
if (min_fd > entries || min_fd <= 0)
return -EINVAL;
memcpy(&fds[i], cmsg_buf, sizeof(fds[0]) * min_fd);
memcpy(&aux->ent[i], amsg_buf, sizeof(aux->ent[0]) * min_fd);
memcpy(aux, mmsg_buf, offsetof(struct bpf_map_aux, ent));
needed = aux->num_ent;
}
return 0;
}
int bpf_send_map_fds(const char *path, const char *obj)
{
struct bpf_elf_ctx *ctx = &__ctx;
struct sockaddr_un addr = { .sun_family = AF_UNIX };
struct bpf_map_data bpf_aux = {
.fds = ctx->map_fds,
.ent = ctx->maps,
.st = &ctx->stat,
.obj = obj,
};
int fd, ret;
fd = socket(AF_UNIX, SOCK_DGRAM, 0);
if (fd < 0) {
fprintf(stderr, "Cannot open socket: %s\n",
strerror(errno));
return -1;
}
strlcpy(addr.sun_path, path, sizeof(addr.sun_path));
ret = connect(fd, (struct sockaddr *)&addr, sizeof(addr));
if (ret < 0) {
fprintf(stderr, "Cannot connect to %s: %s\n",
path, strerror(errno));
return -1;
}
ret = bpf_map_set_send(fd, &addr, sizeof(addr), &bpf_aux,
bpf_maps_count(ctx));
if (ret < 0)
fprintf(stderr, "Cannot send fds to %s: %s\n",
path, strerror(errno));
bpf_maps_teardown(ctx);
close(fd);
return ret;
}
int bpf_recv_map_fds(const char *path, int *fds, struct bpf_map_aux *aux,
unsigned int entries)
{
struct sockaddr_un addr = { .sun_family = AF_UNIX };
int fd, ret;
fd = socket(AF_UNIX, SOCK_DGRAM, 0);
if (fd < 0) {
fprintf(stderr, "Cannot open socket: %s\n",
strerror(errno));
return -1;
}
strlcpy(addr.sun_path, path, sizeof(addr.sun_path));
ret = bind(fd, (struct sockaddr *)&addr, sizeof(addr));
if (ret < 0) {
fprintf(stderr, "Cannot bind to socket: %s\n",
strerror(errno));
return -1;
}
ret = bpf_map_set_recv(fd, fds, aux, entries);
if (ret < 0)
fprintf(stderr, "Cannot recv fds from %s: %s\n",
path, strerror(errno));
unlink(addr.sun_path);
close(fd);
return ret;
}
#endif /* HAVE_ELF */