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-rw-r--r--tools/bpf/bpftool/Documentation/bpftool-gen.rst13
-rw-r--r--tools/bpf/bpftool/Documentation/bpftool-prog.rst14
-rw-r--r--tools/bpf/bpftool/Documentation/bpftool-token.rst64
-rw-r--r--tools/bpf/bpftool/Makefile6
-rw-r--r--tools/bpf/bpftool/bash-completion/bpftool37
-rw-r--r--tools/bpf/bpftool/btf_dumper.c2
-rw-r--r--tools/bpf/bpftool/cgroup.c4
-rw-r--r--tools/bpf/bpftool/common.c93
-rw-r--r--tools/bpf/bpftool/feature.c86
-rw-r--r--tools/bpf/bpftool/gen.c68
-rw-r--r--tools/bpf/bpftool/link.c54
-rw-r--r--tools/bpf/bpftool/main.c29
-rw-r--r--tools/bpf/bpftool/main.h21
-rw-r--r--tools/bpf/bpftool/prog.c33
-rw-r--r--tools/bpf/bpftool/sign.c211
-rw-r--r--tools/bpf/bpftool/token.c210
-rw-r--r--tools/bpf/bpftool/tracelog.c11
17 files changed, 837 insertions, 119 deletions
diff --git a/tools/bpf/bpftool/Documentation/bpftool-gen.rst b/tools/bpf/bpftool/Documentation/bpftool-gen.rst
index ca860fd97d8d..d0a36f442db7 100644
--- a/tools/bpf/bpftool/Documentation/bpftool-gen.rst
+++ b/tools/bpf/bpftool/Documentation/bpftool-gen.rst
@@ -16,7 +16,7 @@ SYNOPSIS
**bpftool** [*OPTIONS*] **gen** *COMMAND*
-*OPTIONS* := { |COMMON_OPTIONS| | { **-L** | **--use-loader** } }
+*OPTIONS* := { |COMMON_OPTIONS| | { **-L** | **--use-loader** } | [ { **-S** | **--sign** } {**-k** <private_key.pem>} **-i** <certificate.x509> ] }
*COMMAND* := { **object** | **skeleton** | **help** }
@@ -186,6 +186,17 @@ OPTIONS
skeleton). A light skeleton contains a loader eBPF program. It does not use
the majority of the libbpf infrastructure, and does not need libelf.
+-S, --sign
+ For skeletons, generate a signed skeleton. This option must be used with
+ **-k** and **-i**. Using this flag implicitly enables **--use-loader**.
+
+-k <private_key.pem>
+ Path to the private key file in PEM format, required for signing.
+
+-i <certificate.x509>
+ Path to the X.509 certificate file in PEM or DER format, required for
+ signing.
+
EXAMPLES
========
**$ cat example1.bpf.c**
diff --git a/tools/bpf/bpftool/Documentation/bpftool-prog.rst b/tools/bpf/bpftool/Documentation/bpftool-prog.rst
index f69fd92df8d8..009633294b09 100644
--- a/tools/bpf/bpftool/Documentation/bpftool-prog.rst
+++ b/tools/bpf/bpftool/Documentation/bpftool-prog.rst
@@ -18,7 +18,7 @@ SYNOPSIS
*OPTIONS* := { |COMMON_OPTIONS| |
{ **-f** | **--bpffs** } | { **-m** | **--mapcompat** } | { **-n** | **--nomount** } |
-{ **-L** | **--use-loader** } }
+{ **-L** | **--use-loader** } | [ { **-S** | **--sign** } **-k** <private_key.pem> **-i** <certificate.x509> ] }
*COMMANDS* :=
{ **show** | **list** | **dump xlated** | **dump jited** | **pin** | **load** |
@@ -248,6 +248,18 @@ OPTIONS
creating the maps, and loading the programs (see **bpftool prog tracelog**
as a way to dump those messages).
+-S, --sign
+ Enable signing of the BPF program before loading. This option must be
+ used with **-k** and **-i**. Using this flag implicitly enables
+ **--use-loader**.
+
+-k <private_key.pem>
+ Path to the private key file in PEM format, required when signing.
+
+-i <certificate.x509>
+ Path to the X.509 certificate file in PEM or DER format, required when
+ signing.
+
EXAMPLES
========
**# bpftool prog show**
diff --git a/tools/bpf/bpftool/Documentation/bpftool-token.rst b/tools/bpf/bpftool/Documentation/bpftool-token.rst
new file mode 100644
index 000000000000..d082c499cfe3
--- /dev/null
+++ b/tools/bpf/bpftool/Documentation/bpftool-token.rst
@@ -0,0 +1,64 @@
+.. SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+
+================
+bpftool-token
+================
+-------------------------------------------------------------------------------
+tool for inspection and simple manipulation of eBPF tokens
+-------------------------------------------------------------------------------
+
+:Manual section: 8
+
+.. include:: substitutions.rst
+
+SYNOPSIS
+========
+
+**bpftool** [*OPTIONS*] **token** *COMMAND*
+
+*OPTIONS* := { |COMMON_OPTIONS| }
+
+*COMMANDS* := { **show** | **list** | **help** }
+
+TOKEN COMMANDS
+===============
+
+| **bpftool** **token** { **show** | **list** }
+| **bpftool** **token help**
+|
+
+DESCRIPTION
+===========
+bpftool token { show | list }
+ List BPF token information for each *bpffs* mount point containing token
+ information on the system. Information include mount point path, allowed
+ **bpf**\ () system call commands, maps, programs, and attach types for the
+ token.
+
+bpftool prog help
+ Print short help message.
+
+OPTIONS
+========
+.. include:: common_options.rst
+
+EXAMPLES
+========
+|
+| **# mkdir -p /sys/fs/bpf/token**
+| **# mount -t bpf bpffs /sys/fs/bpf/token** \
+| **-o delegate_cmds=prog_load:map_create** \
+| **-o delegate_progs=kprobe** \
+| **-o delegate_attachs=xdp**
+| **# bpftool token list**
+
+::
+
+ token_info /sys/fs/bpf/token
+ allowed_cmds:
+ map_create prog_load
+ allowed_maps:
+ allowed_progs:
+ kprobe
+ allowed_attachs:
+ xdp
diff --git a/tools/bpf/bpftool/Makefile b/tools/bpf/bpftool/Makefile
index 9e9a5f006cd2..586d1b2595d1 100644
--- a/tools/bpf/bpftool/Makefile
+++ b/tools/bpf/bpftool/Makefile
@@ -130,8 +130,8 @@ include $(FEATURES_DUMP)
endif
endif
-LIBS = $(LIBBPF) -lelf -lz
-LIBS_BOOTSTRAP = $(LIBBPF_BOOTSTRAP) -lelf -lz
+LIBS = $(LIBBPF) -lelf -lz -lcrypto
+LIBS_BOOTSTRAP = $(LIBBPF_BOOTSTRAP) -lelf -lz -lcrypto
ifeq ($(feature-libelf-zstd),1)
LIBS += -lzstd
@@ -194,7 +194,7 @@ endif
BPFTOOL_BOOTSTRAP := $(BOOTSTRAP_OUTPUT)bpftool
-BOOTSTRAP_OBJS = $(addprefix $(BOOTSTRAP_OUTPUT),main.o common.o json_writer.o gen.o btf.o)
+BOOTSTRAP_OBJS = $(addprefix $(BOOTSTRAP_OUTPUT),main.o common.o json_writer.o gen.o btf.o sign.o)
$(BOOTSTRAP_OBJS): $(LIBBPF_BOOTSTRAP)
OBJS = $(patsubst %.c,$(OUTPUT)%.o,$(SRCS)) $(OUTPUT)disasm.o
diff --git a/tools/bpf/bpftool/bash-completion/bpftool b/tools/bpf/bpftool/bash-completion/bpftool
index a759ba24471d..53bcfeb1a76e 100644
--- a/tools/bpf/bpftool/bash-completion/bpftool
+++ b/tools/bpf/bpftool/bash-completion/bpftool
@@ -262,7 +262,7 @@ _bpftool()
# Deal with options
if [[ ${words[cword]} == -* ]]; then
local c='--version --json --pretty --bpffs --mapcompat --debug \
- --use-loader --base-btf'
+ --use-loader --base-btf --sign -i -k'
COMPREPLY=( $( compgen -W "$c" -- "$cur" ) )
return 0
fi
@@ -283,7 +283,7 @@ _bpftool()
_sysfs_get_netdevs
return 0
;;
- file|pinned|-B|--base-btf)
+ file|pinned|-B|--base-btf|-i|-k)
_filedir
return 0
;;
@@ -296,13 +296,21 @@ _bpftool()
# Remove all options so completions don't have to deal with them.
local i pprev
for (( i=1; i < ${#words[@]}; )); do
- if [[ ${words[i]::1} == - ]] &&
- [[ ${words[i]} != "-B" ]] && [[ ${words[i]} != "--base-btf" ]]; then
- words=( "${words[@]:0:i}" "${words[@]:i+1}" )
- [[ $i -le $cword ]] && cword=$(( cword - 1 ))
- else
- i=$(( ++i ))
- fi
+ case ${words[i]} in
+ # Remove option and its argument
+ -B|--base-btf|-i|-k)
+ words=( "${words[@]:0:i}" "${words[@]:i+2}" )
+ [[ $i -le $(($cword + 1)) ]] && cword=$(( cword - 2 ))
+ ;;
+ # No argument, remove option only
+ -*)
+ words=( "${words[@]:0:i}" "${words[@]:i+1}" )
+ [[ $i -le $cword ]] && cword=$(( cword - 1 ))
+ ;;
+ *)
+ i=$(( ++i ))
+ ;;
+ esac
done
cur=${words[cword]}
prev=${words[cword - 1]}
@@ -1215,6 +1223,17 @@ _bpftool()
;;
esac
;;
+ token)
+ case $command in
+ show|list)
+ return 0
+ ;;
+ *)
+ [[ $prev == $object ]] && \
+ COMPREPLY=( $( compgen -W 'help show list' -- "$cur" ) )
+ ;;
+ esac
+ ;;
esac
} &&
complete -F _bpftool bpftool
diff --git a/tools/bpf/bpftool/btf_dumper.c b/tools/bpf/bpftool/btf_dumper.c
index 4e896d8a2416..ff12628593ae 100644
--- a/tools/bpf/bpftool/btf_dumper.c
+++ b/tools/bpf/bpftool/btf_dumper.c
@@ -38,7 +38,7 @@ static int dump_prog_id_as_func_ptr(const struct btf_dumper *d,
__u32 info_len = sizeof(info);
const char *prog_name = NULL;
struct btf *prog_btf = NULL;
- struct bpf_func_info finfo;
+ struct bpf_func_info finfo = {};
__u32 finfo_rec_size;
char prog_str[1024];
int err;
diff --git a/tools/bpf/bpftool/cgroup.c b/tools/bpf/bpftool/cgroup.c
index 944ebe21a216..ec356deb27c9 100644
--- a/tools/bpf/bpftool/cgroup.c
+++ b/tools/bpf/bpftool/cgroup.c
@@ -2,6 +2,10 @@
// Copyright (C) 2017 Facebook
// Author: Roman Gushchin <guro@fb.com>
+#undef GCC_VERSION
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
#define _XOPEN_SOURCE 500
#include <errno.h>
#include <fcntl.h>
diff --git a/tools/bpf/bpftool/common.c b/tools/bpf/bpftool/common.c
index b07317d2842f..e8daf963ecef 100644
--- a/tools/bpf/bpftool/common.c
+++ b/tools/bpf/bpftool/common.c
@@ -21,6 +21,7 @@
#include <sys/resource.h>
#include <sys/stat.h>
#include <sys/vfs.h>
+#include <sys/utsname.h>
#include <linux/filter.h>
#include <linux/limits.h>
@@ -31,6 +32,7 @@
#include <bpf/hashmap.h>
#include <bpf/libbpf.h> /* libbpf_num_possible_cpus */
#include <bpf/btf.h>
+#include <zlib.h>
#include "main.h"
@@ -1208,3 +1210,94 @@ int pathname_concat(char *buf, int buf_sz, const char *path,
return 0;
}
+
+static bool read_next_kernel_config_option(gzFile file, char *buf, size_t n,
+ char **value)
+{
+ char *sep;
+
+ while (gzgets(file, buf, n)) {
+ if (strncmp(buf, "CONFIG_", 7))
+ continue;
+
+ sep = strchr(buf, '=');
+ if (!sep)
+ continue;
+
+ /* Trim ending '\n' */
+ buf[strlen(buf) - 1] = '\0';
+
+ /* Split on '=' and ensure that a value is present. */
+ *sep = '\0';
+ if (!sep[1])
+ continue;
+
+ *value = sep + 1;
+ return true;
+ }
+
+ return false;
+}
+
+int read_kernel_config(const struct kernel_config_option *requested_options,
+ size_t num_options, char **out_values,
+ const char *define_prefix)
+{
+ struct utsname utsn;
+ char path[PATH_MAX];
+ gzFile file = NULL;
+ char buf[4096];
+ char *value;
+ size_t i;
+ int ret = 0;
+
+ if (!requested_options || !out_values || num_options == 0)
+ return -1;
+
+ if (!uname(&utsn)) {
+ snprintf(path, sizeof(path), "/boot/config-%s", utsn.release);
+
+ /* gzopen also accepts uncompressed files. */
+ file = gzopen(path, "r");
+ }
+
+ if (!file) {
+ /* Some distributions build with CONFIG_IKCONFIG=y and put the
+ * config file at /proc/config.gz.
+ */
+ file = gzopen("/proc/config.gz", "r");
+ }
+
+ if (!file) {
+ p_info("skipping kernel config, can't open file: %s",
+ strerror(errno));
+ return -1;
+ }
+
+ if (!gzgets(file, buf, sizeof(buf)) || !gzgets(file, buf, sizeof(buf))) {
+ p_info("skipping kernel config, can't read from file: %s",
+ strerror(errno));
+ ret = -1;
+ goto end_parse;
+ }
+
+ if (strcmp(buf, "# Automatically generated file; DO NOT EDIT.\n")) {
+ p_info("skipping kernel config, can't find correct file");
+ ret = -1;
+ goto end_parse;
+ }
+
+ while (read_next_kernel_config_option(file, buf, sizeof(buf), &value)) {
+ for (i = 0; i < num_options; i++) {
+ if ((define_prefix && !requested_options[i].macro_dump) ||
+ out_values[i] || strcmp(buf, requested_options[i].name))
+ continue;
+
+ out_values[i] = strdup(value);
+ }
+ }
+
+end_parse:
+ gzclose(file);
+ return ret;
+}
diff --git a/tools/bpf/bpftool/feature.c b/tools/bpf/bpftool/feature.c
index 24fecdf8e430..0f6070a0c8e7 100644
--- a/tools/bpf/bpftool/feature.c
+++ b/tools/bpf/bpftool/feature.c
@@ -10,7 +10,6 @@
#ifdef USE_LIBCAP
#include <sys/capability.h>
#endif
-#include <sys/utsname.h>
#include <sys/vfs.h>
#include <linux/filter.h>
@@ -18,7 +17,6 @@
#include <bpf/bpf.h>
#include <bpf/libbpf.h>
-#include <zlib.h>
#include "main.h"
@@ -327,40 +325,9 @@ static void probe_jit_limit(void)
}
}
-static bool read_next_kernel_config_option(gzFile file, char *buf, size_t n,
- char **value)
-{
- char *sep;
-
- while (gzgets(file, buf, n)) {
- if (strncmp(buf, "CONFIG_", 7))
- continue;
-
- sep = strchr(buf, '=');
- if (!sep)
- continue;
-
- /* Trim ending '\n' */
- buf[strlen(buf) - 1] = '\0';
-
- /* Split on '=' and ensure that a value is present. */
- *sep = '\0';
- if (!sep[1])
- continue;
-
- *value = sep + 1;
- return true;
- }
-
- return false;
-}
-
static void probe_kernel_image_config(const char *define_prefix)
{
- static const struct {
- const char * const name;
- bool macro_dump;
- } options[] = {
+ struct kernel_config_option options[] = {
/* Enable BPF */
{ "CONFIG_BPF", },
/* Enable bpf() syscall */
@@ -435,52 +402,11 @@ static void probe_kernel_image_config(const char *define_prefix)
{ "CONFIG_HZ", true, }
};
char *values[ARRAY_SIZE(options)] = { };
- struct utsname utsn;
- char path[PATH_MAX];
- gzFile file = NULL;
- char buf[4096];
- char *value;
size_t i;
- if (!uname(&utsn)) {
- snprintf(path, sizeof(path), "/boot/config-%s", utsn.release);
-
- /* gzopen also accepts uncompressed files. */
- file = gzopen(path, "r");
- }
-
- if (!file) {
- /* Some distributions build with CONFIG_IKCONFIG=y and put the
- * config file at /proc/config.gz.
- */
- file = gzopen("/proc/config.gz", "r");
- }
- if (!file) {
- p_info("skipping kernel config, can't open file: %s",
- strerror(errno));
- goto end_parse;
- }
- /* Sanity checks */
- if (!gzgets(file, buf, sizeof(buf)) ||
- !gzgets(file, buf, sizeof(buf))) {
- p_info("skipping kernel config, can't read from file: %s",
- strerror(errno));
- goto end_parse;
- }
- if (strcmp(buf, "# Automatically generated file; DO NOT EDIT.\n")) {
- p_info("skipping kernel config, can't find correct file");
- goto end_parse;
- }
-
- while (read_next_kernel_config_option(file, buf, sizeof(buf), &value)) {
- for (i = 0; i < ARRAY_SIZE(options); i++) {
- if ((define_prefix && !options[i].macro_dump) ||
- values[i] || strcmp(buf, options[i].name))
- continue;
-
- values[i] = strdup(value);
- }
- }
+ if (read_kernel_config(options, ARRAY_SIZE(options), values,
+ define_prefix))
+ return;
for (i = 0; i < ARRAY_SIZE(options); i++) {
if (define_prefix && !options[i].macro_dump)
@@ -488,10 +414,6 @@ static void probe_kernel_image_config(const char *define_prefix)
print_kernel_option(options[i].name, values[i], define_prefix);
free(values[i]);
}
-
-end_parse:
- if (file)
- gzclose(file);
}
static bool probe_bpf_syscall(const char *define_prefix)
diff --git a/tools/bpf/bpftool/gen.c b/tools/bpf/bpftool/gen.c
index 67a60114368f..993c7d9484a4 100644
--- a/tools/bpf/bpftool/gen.c
+++ b/tools/bpf/bpftool/gen.c
@@ -688,10 +688,17 @@ static void codegen_destroy(struct bpf_object *obj, const char *obj_name)
static int gen_trace(struct bpf_object *obj, const char *obj_name, const char *header_guard)
{
DECLARE_LIBBPF_OPTS(gen_loader_opts, opts);
+ struct bpf_load_and_run_opts sopts = {};
+ char sig_buf[MAX_SIG_SIZE];
+ __u8 prog_sha[SHA256_DIGEST_LENGTH];
struct bpf_map *map;
+
char ident[256];
int err = 0;
+ if (sign_progs)
+ opts.gen_hash = true;
+
err = bpf_object__gen_loader(obj, &opts);
if (err)
return err;
@@ -701,6 +708,7 @@ static int gen_trace(struct bpf_object *obj, const char *obj_name, const char *h
p_err("failed to load object file");
goto out;
}
+
/* If there was no error during load then gen_loader_opts
* are populated with the loader program.
*/
@@ -780,8 +788,52 @@ static int gen_trace(struct bpf_object *obj, const char *obj_name, const char *h
print_hex(opts.insns, opts.insns_sz);
codegen("\
\n\
- \"; \n\
- \n\
+ \";\n");
+
+ if (sign_progs) {
+ sopts.insns = opts.insns;
+ sopts.insns_sz = opts.insns_sz;
+ sopts.excl_prog_hash = prog_sha;
+ sopts.excl_prog_hash_sz = sizeof(prog_sha);
+ sopts.signature = sig_buf;
+ sopts.signature_sz = MAX_SIG_SIZE;
+
+ err = bpftool_prog_sign(&sopts);
+ if (err < 0) {
+ p_err("failed to sign program");
+ goto out;
+ }
+
+ codegen("\
+ \n\
+ static const char opts_sig[] __attribute__((__aligned__(8))) = \"\\\n\
+ ");
+ print_hex((const void *)sig_buf, sopts.signature_sz);
+ codegen("\
+ \n\
+ \";\n");
+
+ codegen("\
+ \n\
+ static const char opts_excl_hash[] __attribute__((__aligned__(8))) = \"\\\n\
+ ");
+ print_hex((const void *)prog_sha, sizeof(prog_sha));
+ codegen("\
+ \n\
+ \";\n");
+
+ codegen("\
+ \n\
+ opts.signature = (void *)opts_sig; \n\
+ opts.signature_sz = sizeof(opts_sig) - 1; \n\
+ opts.excl_prog_hash = (void *)opts_excl_hash; \n\
+ opts.excl_prog_hash_sz = sizeof(opts_excl_hash) - 1; \n\
+ opts.keyring_id = skel->keyring_id; \n\
+ ");
+ }
+
+ codegen("\
+ \n\
opts.ctx = (struct bpf_loader_ctx *)skel; \n\
opts.data_sz = sizeof(opts_data) - 1; \n\
opts.data = (void *)opts_data; \n\
@@ -1240,7 +1292,7 @@ static int do_skeleton(int argc, char **argv)
err = -errno;
libbpf_strerror(err, err_buf, sizeof(err_buf));
p_err("failed to open BPF object file: %s", err_buf);
- goto out;
+ goto out_obj;
}
bpf_object__for_each_map(map, obj) {
@@ -1355,6 +1407,13 @@ static int do_skeleton(int argc, char **argv)
printf("\t} links;\n");
}
+ if (sign_progs) {
+ codegen("\
+ \n\
+ __s32 keyring_id; \n\
+ ");
+ }
+
if (btf) {
err = codegen_datasecs(obj, obj_name);
if (err)
@@ -1552,6 +1611,7 @@ static int do_skeleton(int argc, char **argv)
err = 0;
out:
bpf_object__close(obj);
+out_obj:
if (obj_data)
munmap(obj_data, mmap_sz);
close(fd);
@@ -1930,7 +1990,7 @@ static int do_help(int argc, char **argv)
" %1$s %2$s help\n"
"\n"
" " HELP_SPEC_OPTIONS " |\n"
- " {-L|--use-loader} }\n"
+ " {-L|--use-loader} | [ {-S|--sign } {-k} <private_key.pem> {-i} <certificate.x509> ]}\n"
"",
bin_name, "gen");
diff --git a/tools/bpf/bpftool/link.c b/tools/bpf/bpftool/link.c
index a773e05d5ade..bdcd717b0348 100644
--- a/tools/bpf/bpftool/link.c
+++ b/tools/bpf/bpftool/link.c
@@ -282,11 +282,52 @@ get_addr_cookie_array(__u64 *addrs, __u64 *cookies, __u32 count)
return data;
}
+static bool is_x86_ibt_enabled(void)
+{
+#if defined(__x86_64__)
+ struct kernel_config_option options[] = {
+ { "CONFIG_X86_KERNEL_IBT", },
+ };
+ char *values[ARRAY_SIZE(options)] = { };
+ bool ret;
+
+ if (read_kernel_config(options, ARRAY_SIZE(options), values, NULL))
+ return false;
+
+ ret = !!values[0];
+ free(values[0]);
+ return ret;
+#else
+ return false;
+#endif
+}
+
+static bool
+symbol_matches_target(__u64 sym_addr, __u64 target_addr, bool is_ibt_enabled)
+{
+ if (sym_addr == target_addr)
+ return true;
+
+ /*
+ * On x86_64 architectures with CET (Control-flow Enforcement Technology),
+ * function entry points have a 4-byte 'endbr' instruction prefix.
+ * This causes kprobe hooks to target the address *after* 'endbr'
+ * (symbol address + 4), preserving the CET instruction.
+ * Here we check if the symbol address matches the hook target address
+ * minus 4, indicating a CET-enabled function entry point.
+ */
+ if (is_ibt_enabled && sym_addr == target_addr - 4)
+ return true;
+
+ return false;
+}
+
static void
show_kprobe_multi_json(struct bpf_link_info *info, json_writer_t *wtr)
{
struct addr_cookie *data;
__u32 i, j = 0;
+ bool is_ibt_enabled;
jsonw_bool_field(json_wtr, "retprobe",
info->kprobe_multi.flags & BPF_F_KPROBE_MULTI_RETURN);
@@ -306,11 +347,13 @@ show_kprobe_multi_json(struct bpf_link_info *info, json_writer_t *wtr)
if (!dd.sym_count)
goto error;
+ is_ibt_enabled = is_x86_ibt_enabled();
for (i = 0; i < dd.sym_count; i++) {
- if (dd.sym_mapping[i].address != data[j].addr)
+ if (!symbol_matches_target(dd.sym_mapping[i].address,
+ data[j].addr, is_ibt_enabled))
continue;
jsonw_start_object(json_wtr);
- jsonw_uint_field(json_wtr, "addr", dd.sym_mapping[i].address);
+ jsonw_uint_field(json_wtr, "addr", (unsigned long)data[j].addr);
jsonw_string_field(json_wtr, "func", dd.sym_mapping[i].name);
/* Print null if it is vmlinux */
if (dd.sym_mapping[i].module[0] == '\0') {
@@ -719,6 +762,7 @@ static void show_kprobe_multi_plain(struct bpf_link_info *info)
{
struct addr_cookie *data;
__u32 i, j = 0;
+ bool is_ibt_enabled;
if (!info->kprobe_multi.count)
return;
@@ -742,12 +786,14 @@ static void show_kprobe_multi_plain(struct bpf_link_info *info)
if (!dd.sym_count)
goto error;
+ is_ibt_enabled = is_x86_ibt_enabled();
printf("\n\t%-16s %-16s %s", "addr", "cookie", "func [module]");
for (i = 0; i < dd.sym_count; i++) {
- if (dd.sym_mapping[i].address != data[j].addr)
+ if (!symbol_matches_target(dd.sym_mapping[i].address,
+ data[j].addr, is_ibt_enabled))
continue;
printf("\n\t%016lx %-16llx %s",
- dd.sym_mapping[i].address, data[j].cookie, dd.sym_mapping[i].name);
+ (unsigned long)data[j].addr, data[j].cookie, dd.sym_mapping[i].name);
if (dd.sym_mapping[i].module[0] != '\0')
printf(" [%s] ", dd.sym_mapping[i].module);
else
diff --git a/tools/bpf/bpftool/main.c b/tools/bpf/bpftool/main.c
index 2b7f2bd3a7db..a829a6a49037 100644
--- a/tools/bpf/bpftool/main.c
+++ b/tools/bpf/bpftool/main.c
@@ -33,6 +33,9 @@ bool relaxed_maps;
bool use_loader;
struct btf *base_btf;
struct hashmap *refs_table;
+bool sign_progs;
+const char *private_key_path;
+const char *cert_path;
static void __noreturn clean_and_exit(int i)
{
@@ -61,7 +64,7 @@ static int do_help(int argc, char **argv)
" %s batch file FILE\n"
" %s version\n"
"\n"
- " OBJECT := { prog | map | link | cgroup | perf | net | feature | btf | gen | struct_ops | iter }\n"
+ " OBJECT := { prog | map | link | cgroup | perf | net | feature | btf | gen | struct_ops | iter | token }\n"
" " HELP_SPEC_OPTIONS " |\n"
" {-V|--version} }\n"
"",
@@ -87,6 +90,7 @@ static const struct cmd commands[] = {
{ "gen", do_gen },
{ "struct_ops", do_struct_ops },
{ "iter", do_iter },
+ { "token", do_token },
{ "version", do_version },
{ 0 }
};
@@ -447,6 +451,7 @@ int main(int argc, char **argv)
{ "nomount", no_argument, NULL, 'n' },
{ "debug", no_argument, NULL, 'd' },
{ "use-loader", no_argument, NULL, 'L' },
+ { "sign", no_argument, NULL, 'S' },
{ "base-btf", required_argument, NULL, 'B' },
{ 0 }
};
@@ -473,7 +478,7 @@ int main(int argc, char **argv)
bin_name = "bpftool";
opterr = 0;
- while ((opt = getopt_long(argc, argv, "VhpjfLmndB:l",
+ while ((opt = getopt_long(argc, argv, "VhpjfLmndSi:k:B:l",
options, NULL)) >= 0) {
switch (opt) {
case 'V':
@@ -519,6 +524,16 @@ int main(int argc, char **argv)
case 'L':
use_loader = true;
break;
+ case 'S':
+ sign_progs = true;
+ use_loader = true;
+ break;
+ case 'k':
+ private_key_path = optarg;
+ break;
+ case 'i':
+ cert_path = optarg;
+ break;
default:
p_err("unrecognized option '%s'", argv[optind - 1]);
if (json_output)
@@ -533,6 +548,16 @@ int main(int argc, char **argv)
if (argc < 0)
usage();
+ if (sign_progs && (private_key_path == NULL || cert_path == NULL)) {
+ p_err("-i <identity_x509_cert> and -k <private_key> must be supplied with -S for signing");
+ return -EINVAL;
+ }
+
+ if (!sign_progs && (private_key_path != NULL || cert_path != NULL)) {
+ p_err("--sign (or -S) must be explicitly passed with -i <identity_x509_cert> and -k <private_key> to sign the programs");
+ return -EINVAL;
+ }
+
if (version_requested)
ret = do_version(argc, argv);
else
diff --git a/tools/bpf/bpftool/main.h b/tools/bpf/bpftool/main.h
index 6db704fda5c0..1130299cede0 100644
--- a/tools/bpf/bpftool/main.h
+++ b/tools/bpf/bpftool/main.h
@@ -6,9 +6,14 @@
/* BFD and kernel.h both define GCC_VERSION, differently */
#undef GCC_VERSION
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
#include <stdbool.h>
#include <stdio.h>
+#include <errno.h>
#include <stdlib.h>
+#include <bpf/skel_internal.h>
#include <linux/bpf.h>
#include <linux/compiler.h>
#include <linux/kernel.h>
@@ -52,6 +57,7 @@ static inline void *u64_to_ptr(__u64 ptr)
})
#define ERR_MAX_LEN 1024
+#define MAX_SIG_SIZE 4096
#define BPF_TAG_FMT "%02hhx%02hhx%02hhx%02hhx%02hhx%02hhx%02hhx%02hhx"
@@ -85,6 +91,9 @@ extern bool relaxed_maps;
extern bool use_loader;
extern struct btf *base_btf;
extern struct hashmap *refs_table;
+extern bool sign_progs;
+extern const char *private_key_path;
+extern const char *cert_path;
void __printf(1, 2) p_err(const char *fmt, ...);
void __printf(1, 2) p_info(const char *fmt, ...);
@@ -166,6 +175,7 @@ int do_tracelog(int argc, char **arg) __weak;
int do_feature(int argc, char **argv) __weak;
int do_struct_ops(int argc, char **argv) __weak;
int do_iter(int argc, char **argv) __weak;
+int do_token(int argc, char **argv) __weak;
int parse_u32_arg(int *argc, char ***argv, __u32 *val, const char *what);
int prog_parse_fd(int *argc, char ***argv);
@@ -274,4 +284,15 @@ int pathname_concat(char *buf, int buf_sz, const char *path,
/* print netfilter bpf_link info */
void netfilter_dump_plain(const struct bpf_link_info *info);
void netfilter_dump_json(const struct bpf_link_info *info, json_writer_t *wtr);
+
+struct kernel_config_option {
+ const char *name;
+ bool macro_dump;
+};
+
+int read_kernel_config(const struct kernel_config_option *requested_options,
+ size_t num_options, char **out_values,
+ const char *define_prefix);
+int bpftool_prog_sign(struct bpf_load_and_run_opts *opts);
+__u32 register_session_key(const char *key_der_path);
#endif
diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
index 9722d841abc0..6daf19809ca4 100644
--- a/tools/bpf/bpftool/prog.c
+++ b/tools/bpf/bpftool/prog.c
@@ -23,6 +23,7 @@
#include <linux/err.h>
#include <linux/perf_event.h>
#include <linux/sizes.h>
+#include <linux/keyctl.h>
#include <bpf/bpf.h>
#include <bpf/btf.h>
@@ -714,7 +715,7 @@ prog_dump(struct bpf_prog_info *info, enum dump_mode mode,
if (mode == DUMP_JITED) {
if (info->jited_prog_len == 0 || !info->jited_prog_insns) {
- p_info("no instructions returned");
+ p_err("error retrieving jit dump: no instructions returned or kernel.kptr_restrict set?");
return -1;
}
buf = u64_to_ptr(info->jited_prog_insns);
@@ -1930,6 +1931,8 @@ static int try_loader(struct gen_loader_opts *gen)
{
struct bpf_load_and_run_opts opts = {};
struct bpf_loader_ctx *ctx;
+ char sig_buf[MAX_SIG_SIZE];
+ __u8 prog_sha[SHA256_DIGEST_LENGTH];
int ctx_sz = sizeof(*ctx) + 64 * max(sizeof(struct bpf_map_desc),
sizeof(struct bpf_prog_desc));
int log_buf_sz = (1u << 24) - 1;
@@ -1953,6 +1956,26 @@ static int try_loader(struct gen_loader_opts *gen)
opts.insns = gen->insns;
opts.insns_sz = gen->insns_sz;
fds_before = count_open_fds();
+
+ if (sign_progs) {
+ opts.excl_prog_hash = prog_sha;
+ opts.excl_prog_hash_sz = sizeof(prog_sha);
+ opts.signature = sig_buf;
+ opts.signature_sz = MAX_SIG_SIZE;
+ opts.keyring_id = KEY_SPEC_SESSION_KEYRING;
+
+ err = bpftool_prog_sign(&opts);
+ if (err < 0) {
+ p_err("failed to sign program");
+ goto out;
+ }
+
+ err = register_session_key(cert_path);
+ if (err < 0) {
+ p_err("failed to add session key");
+ goto out;
+ }
+ }
err = bpf_load_and_run(&opts);
fd_delta = count_open_fds() - fds_before;
if (err < 0 || verifier_logs) {
@@ -1961,6 +1984,7 @@ static int try_loader(struct gen_loader_opts *gen)
fprintf(stderr, "loader prog leaked %d FDs\n",
fd_delta);
}
+out:
free(log_buf);
return err;
}
@@ -1988,6 +2012,9 @@ static int do_loader(int argc, char **argv)
goto err_close_obj;
}
+ if (sign_progs)
+ gen.gen_hash = true;
+
err = bpf_object__gen_loader(obj, &gen);
if (err)
goto err_close_obj;
@@ -2262,7 +2289,7 @@ static void profile_print_readings(void)
static char *profile_target_name(int tgt_fd)
{
- struct bpf_func_info func_info;
+ struct bpf_func_info func_info = {};
struct bpf_prog_info info = {};
__u32 info_len = sizeof(info);
const struct btf_type *t;
@@ -2562,7 +2589,7 @@ static int do_help(int argc, char **argv)
" METRIC := { cycles | instructions | l1d_loads | llc_misses | itlb_misses | dtlb_misses }\n"
" " HELP_SPEC_OPTIONS " |\n"
" {-f|--bpffs} | {-m|--mapcompat} | {-n|--nomount} |\n"
- " {-L|--use-loader} }\n"
+ " {-L|--use-loader} | [ {-S|--sign } {-k} <private_key.pem> {-i} <certificate.x509> ] \n"
"",
bin_name, argv[-2]);
diff --git a/tools/bpf/bpftool/sign.c b/tools/bpf/bpftool/sign.c
new file mode 100644
index 000000000000..b34f74d210e9
--- /dev/null
+++ b/tools/bpf/bpftool/sign.c
@@ -0,0 +1,211 @@
+// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+/*
+ * Copyright (C) 2025 Google LLC.
+ */
+
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <string.h>
+#include <getopt.h>
+#include <err.h>
+#include <openssl/opensslv.h>
+#include <openssl/bio.h>
+#include <openssl/evp.h>
+#include <openssl/pem.h>
+#include <openssl/err.h>
+#include <openssl/cms.h>
+#include <linux/keyctl.h>
+#include <errno.h>
+
+#include <bpf/skel_internal.h>
+
+#include "main.h"
+
+#define OPEN_SSL_ERR_BUF_LEN 256
+
+static void display_openssl_errors(int l)
+{
+ char buf[OPEN_SSL_ERR_BUF_LEN];
+ const char *file;
+ const char *data;
+ unsigned long e;
+ int flags;
+ int line;
+
+ while ((e = ERR_get_error_all(&file, &line, NULL, &data, &flags))) {
+ ERR_error_string_n(e, buf, sizeof(buf));
+ if (data && (flags & ERR_TXT_STRING)) {
+ p_err("OpenSSL %s: %s:%d: %s", buf, file, line, data);
+ } else {
+ p_err("OpenSSL %s: %s:%d", buf, file, line);
+ }
+ }
+}
+
+#define DISPLAY_OSSL_ERR(cond) \
+ do { \
+ bool __cond = (cond); \
+ if (__cond && ERR_peek_error()) \
+ display_openssl_errors(__LINE__);\
+ } while (0)
+
+static EVP_PKEY *read_private_key(const char *pkey_path)
+{
+ EVP_PKEY *private_key = NULL;
+ BIO *b;
+
+ b = BIO_new_file(pkey_path, "rb");
+ private_key = PEM_read_bio_PrivateKey(b, NULL, NULL, NULL);
+ BIO_free(b);
+ DISPLAY_OSSL_ERR(!private_key);
+ return private_key;
+}
+
+static X509 *read_x509(const char *x509_name)
+{
+ unsigned char buf[2];
+ X509 *x509 = NULL;
+ BIO *b;
+ int n;
+
+ b = BIO_new_file(x509_name, "rb");
+ if (!b)
+ goto cleanup;
+
+ /* Look at the first two bytes of the file to determine the encoding */
+ n = BIO_read(b, buf, 2);
+ if (n != 2)
+ goto cleanup;
+
+ if (BIO_reset(b) != 0)
+ goto cleanup;
+
+ if (buf[0] == 0x30 && buf[1] >= 0x81 && buf[1] <= 0x84)
+ /* Assume raw DER encoded X.509 */
+ x509 = d2i_X509_bio(b, NULL);
+ else
+ /* Assume PEM encoded X.509 */
+ x509 = PEM_read_bio_X509(b, NULL, NULL, NULL);
+
+cleanup:
+ BIO_free(b);
+ DISPLAY_OSSL_ERR(!x509);
+ return x509;
+}
+
+__u32 register_session_key(const char *key_der_path)
+{
+ unsigned char *der_buf = NULL;
+ X509 *x509 = NULL;
+ int key_id = -1;
+ int der_len;
+
+ if (!key_der_path)
+ return key_id;
+ x509 = read_x509(key_der_path);
+ if (!x509)
+ goto cleanup;
+ der_len = i2d_X509(x509, &der_buf);
+ if (der_len < 0)
+ goto cleanup;
+ key_id = syscall(__NR_add_key, "asymmetric", key_der_path, der_buf,
+ (size_t)der_len, KEY_SPEC_SESSION_KEYRING);
+cleanup:
+ X509_free(x509);
+ OPENSSL_free(der_buf);
+ DISPLAY_OSSL_ERR(key_id == -1);
+ return key_id;
+}
+
+int bpftool_prog_sign(struct bpf_load_and_run_opts *opts)
+{
+ BIO *bd_in = NULL, *bd_out = NULL;
+ EVP_PKEY *private_key = NULL;
+ CMS_ContentInfo *cms = NULL;
+ long actual_sig_len = 0;
+ X509 *x509 = NULL;
+ int err = 0;
+
+ bd_in = BIO_new_mem_buf(opts->insns, opts->insns_sz);
+ if (!bd_in) {
+ err = -ENOMEM;
+ goto cleanup;
+ }
+
+ private_key = read_private_key(private_key_path);
+ if (!private_key) {
+ err = -EINVAL;
+ goto cleanup;
+ }
+
+ x509 = read_x509(cert_path);
+ if (!x509) {
+ err = -EINVAL;
+ goto cleanup;
+ }
+
+ cms = CMS_sign(NULL, NULL, NULL, NULL,
+ CMS_NOCERTS | CMS_PARTIAL | CMS_BINARY | CMS_DETACHED |
+ CMS_STREAM);
+ if (!cms) {
+ err = -EINVAL;
+ goto cleanup;
+ }
+
+ if (!CMS_add1_signer(cms, x509, private_key, EVP_sha256(),
+ CMS_NOCERTS | CMS_BINARY | CMS_NOSMIMECAP |
+ CMS_USE_KEYID | CMS_NOATTR)) {
+ err = -EINVAL;
+ goto cleanup;
+ }
+
+ if (CMS_final(cms, bd_in, NULL, CMS_NOCERTS | CMS_BINARY) != 1) {
+ err = -EIO;
+ goto cleanup;
+ }
+
+ EVP_Digest(opts->insns, opts->insns_sz, opts->excl_prog_hash,
+ &opts->excl_prog_hash_sz, EVP_sha256(), NULL);
+
+ bd_out = BIO_new(BIO_s_mem());
+ if (!bd_out) {
+ err = -ENOMEM;
+ goto cleanup;
+ }
+
+ if (!i2d_CMS_bio_stream(bd_out, cms, NULL, 0)) {
+ err = -EIO;
+ goto cleanup;
+ }
+
+ actual_sig_len = BIO_get_mem_data(bd_out, NULL);
+ if (actual_sig_len <= 0) {
+ err = -EIO;
+ goto cleanup;
+ }
+
+ if ((size_t)actual_sig_len > opts->signature_sz) {
+ err = -ENOSPC;
+ goto cleanup;
+ }
+
+ if (BIO_read(bd_out, opts->signature, actual_sig_len) != actual_sig_len) {
+ err = -EIO;
+ goto cleanup;
+ }
+
+ opts->signature_sz = actual_sig_len;
+cleanup:
+ BIO_free(bd_out);
+ CMS_ContentInfo_free(cms);
+ X509_free(x509);
+ EVP_PKEY_free(private_key);
+ BIO_free(bd_in);
+ DISPLAY_OSSL_ERR(err < 0);
+ return err;
+}
diff --git a/tools/bpf/bpftool/token.c b/tools/bpf/bpftool/token.c
new file mode 100644
index 000000000000..c08f34b9d51b
--- /dev/null
+++ b/tools/bpf/bpftool/token.c
@@ -0,0 +1,210 @@
+// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+/* Copyright (C) 2025 Didi Technology Co., Tao Chen */
+
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+#include <errno.h>
+#include <fcntl.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <mntent.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include "json_writer.h"
+#include "main.h"
+
+#define MOUNTS_FILE "/proc/mounts"
+
+static struct {
+ const char *header;
+ const char *key;
+} sets[] = {
+ {"allowed_cmds", "delegate_cmds"},
+ {"allowed_maps", "delegate_maps"},
+ {"allowed_progs", "delegate_progs"},
+ {"allowed_attachs", "delegate_attachs"},
+};
+
+static bool has_delegate_options(const char *mnt_ops)
+{
+ return strstr(mnt_ops, "delegate_cmds") ||
+ strstr(mnt_ops, "delegate_maps") ||
+ strstr(mnt_ops, "delegate_progs") ||
+ strstr(mnt_ops, "delegate_attachs");
+}
+
+static char *get_delegate_value(char *opts, const char *key)
+{
+ char *token, *rest, *ret = NULL;
+
+ if (!opts)
+ return NULL;
+
+ for (token = strtok_r(opts, ",", &rest); token;
+ token = strtok_r(NULL, ",", &rest)) {
+ if (strncmp(token, key, strlen(key)) == 0 &&
+ token[strlen(key)] == '=') {
+ ret = token + strlen(key) + 1;
+ break;
+ }
+ }
+
+ return ret;
+}
+
+static void print_items_per_line(char *input, int items_per_line)
+{
+ char *str, *rest;
+ int cnt = 0;
+
+ if (!input)
+ return;
+
+ for (str = strtok_r(input, ":", &rest); str;
+ str = strtok_r(NULL, ":", &rest)) {
+ if (cnt % items_per_line == 0)
+ printf("\n\t ");
+
+ printf("%-20s", str);
+ cnt++;
+ }
+}
+
+#define ITEMS_PER_LINE 4
+static void show_token_info_plain(struct mntent *mntent)
+{
+ size_t i;
+
+ printf("token_info %s", mntent->mnt_dir);
+
+ for (i = 0; i < ARRAY_SIZE(sets); i++) {
+ char *opts, *value;
+
+ printf("\n\t%s:", sets[i].header);
+ opts = strdup(mntent->mnt_opts);
+ value = get_delegate_value(opts, sets[i].key);
+ print_items_per_line(value, ITEMS_PER_LINE);
+ free(opts);
+ }
+
+ printf("\n");
+}
+
+static void split_json_array_str(char *input)
+{
+ char *str, *rest;
+
+ if (!input) {
+ jsonw_start_array(json_wtr);
+ jsonw_end_array(json_wtr);
+ return;
+ }
+
+ jsonw_start_array(json_wtr);
+ for (str = strtok_r(input, ":", &rest); str;
+ str = strtok_r(NULL, ":", &rest)) {
+ jsonw_string(json_wtr, str);
+ }
+ jsonw_end_array(json_wtr);
+}
+
+static void show_token_info_json(struct mntent *mntent)
+{
+ size_t i;
+
+ jsonw_start_object(json_wtr);
+ jsonw_string_field(json_wtr, "token_info", mntent->mnt_dir);
+
+ for (i = 0; i < ARRAY_SIZE(sets); i++) {
+ char *opts, *value;
+
+ jsonw_name(json_wtr, sets[i].header);
+ opts = strdup(mntent->mnt_opts);
+ value = get_delegate_value(opts, sets[i].key);
+ split_json_array_str(value);
+ free(opts);
+ }
+
+ jsonw_end_object(json_wtr);
+}
+
+static int __show_token_info(struct mntent *mntent)
+{
+ if (json_output)
+ show_token_info_json(mntent);
+ else
+ show_token_info_plain(mntent);
+
+ return 0;
+}
+
+static int show_token_info(void)
+{
+ FILE *fp;
+ struct mntent *ent;
+
+ fp = setmntent(MOUNTS_FILE, "r");
+ if (!fp) {
+ p_err("Failed to open: %s", MOUNTS_FILE);
+ return -1;
+ }
+
+ if (json_output)
+ jsonw_start_array(json_wtr);
+
+ while ((ent = getmntent(fp)) != NULL) {
+ if (strncmp(ent->mnt_type, "bpf", 3) == 0) {
+ if (has_delegate_options(ent->mnt_opts))
+ __show_token_info(ent);
+ }
+ }
+
+ if (json_output)
+ jsonw_end_array(json_wtr);
+
+ endmntent(fp);
+
+ return 0;
+}
+
+static int do_show(int argc, char **argv)
+{
+ if (argc)
+ return BAD_ARG();
+
+ return show_token_info();
+}
+
+static int do_help(int argc, char **argv)
+{
+ if (json_output) {
+ jsonw_null(json_wtr);
+ return 0;
+ }
+
+ fprintf(stderr,
+ "Usage: %1$s %2$s { show | list }\n"
+ " %1$s %2$s help\n"
+ " " HELP_SPEC_OPTIONS " }\n"
+ "\n"
+ "",
+ bin_name, argv[-2]);
+ return 0;
+}
+
+static const struct cmd cmds[] = {
+ { "show", do_show },
+ { "list", do_show },
+ { "help", do_help },
+ { 0 }
+};
+
+int do_token(int argc, char **argv)
+{
+ return cmd_select(cmds, argc, argv, do_help);
+}
diff --git a/tools/bpf/bpftool/tracelog.c b/tools/bpf/bpftool/tracelog.c
index 31d806e3bdaa..573a8d99f009 100644
--- a/tools/bpf/bpftool/tracelog.c
+++ b/tools/bpf/bpftool/tracelog.c
@@ -57,10 +57,8 @@ find_tracefs_mnt_single(unsigned long magic, char *mnt, const char *mntpt)
static bool get_tracefs_pipe(char *mnt)
{
static const char * const known_mnts[] = {
- "/sys/kernel/debug/tracing",
"/sys/kernel/tracing",
- "/tracing",
- "/trace",
+ "/sys/kernel/debug/tracing",
};
const char *pipe_name = "/trace_pipe";
const char *fstype = "tracefs";
@@ -95,12 +93,7 @@ static bool get_tracefs_pipe(char *mnt)
return false;
p_info("could not find tracefs, attempting to mount it now");
- /* Most of the time, tracefs is automatically mounted by debugfs at
- * /sys/kernel/debug/tracing when we try to access it. If we could not
- * find it, it is likely that debugfs is not mounted. Let's give one
- * attempt at mounting just tracefs at /sys/kernel/tracing.
- */
- strcpy(mnt, known_mnts[1]);
+ strcpy(mnt, known_mnts[0]);
if (mount_tracefs(mnt))
return false;