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Fix unreadable Enhanced Session Recording events #64581

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Fix unreadable Enhanced Session Recording events #64581

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6423482
refactor command event tracing
capnspacehook Mar 12, 2026
d1c01f4
refactor disk event tracing
capnspacehook Mar 12, 2026
d932a81
use bpf_d_path instead of tracee's path building code
capnspacehook Mar 12, 2026
4c335ad
address Codex feedback
capnspacehook Mar 12, 2026
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168 changes: 33 additions & 135 deletions bpf/enhancedrecording/command.bpf.c
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Original file line number Diff line number Diff line change
Expand Up @@ -8,38 +8,25 @@
// Size, in bytes, of the ring buffer used to report
// audit events to userspace. This is the default,
// the userspace can adjust this value based on config.
#define EVENTS_BUF_SIZE (4096*8)
#define EVENTS_BUF_SIZE (4096 * 128)

char LICENSE[] SEC("license") = "Dual BSD/GPL";

enum event_type {
EVENT_ARG,
EVENT_RET,
};

// common_data_t is a struct used to store fields that are common across
// multiple events. Those fields are the same as `data_t`.
struct common_data_t {
u64 pid;
u64 ppid;
u8 command[TASK_COMM_LEN];
u64 cgroup;
u32 audit_session_id;
};

struct data_t {
// pid as in the userspace term (i.e. task->tgid in kernel).
u64 pid;
// ppid is the userspace term (i.e task->real_parent->tgid in kernel).
u64 ppid;
// Command is the executable.
u8 command[TASK_COMM_LEN];
// Type is the type of event.
enum event_type type;
// Argv is the list of arguments to the program.
u8 argv[ARGSIZE];
// ReturnCode is the return code of execve.
int retval;
// Filename is the path of the executable.
u8 filename[FILENAMESIZE];
// Args is the list of arguments to the program.
u8 args[ARGBUFSIZE];
// ArgsLen is the length of the args.
u64 args_len;
// ArgsTruncated is true if the args were truncated.
bool args_truncated;
// CgroupID is the internal cgroupv2 ID of the event.
u64 cgroup;
// AuditSessionID is the audit session ID that is used to correlate
Expand All @@ -59,144 +46,55 @@ BPF_RING_BUF(execve_events, EVENTS_BUF_SIZE);

BPF_COUNTER(lost);

static int __submit_arg(void *ptr, struct common_data_t *common)
static int enter_execve(struct trace_event_raw_sched_process_exec *tp)
{
struct data_t *data = bpf_ringbuf_reserve(&execve_events, sizeof(*data), 0);
if (!data) {
return -1;
}

if (bpf_probe_read_user(data->argv, sizeof(data->argv), ptr) < 0) {
bpf_ringbuf_discard(data, 0);
return -1;
}

data->type = EVENT_ARG;
data->pid = common->pid;
data->cgroup = common->cgroup;
data->audit_session_id = common->audit_session_id;
for (int i = 0; i < TASK_COMM_LEN; i++)
data->command[i] = common->command[i];

bpf_ringbuf_submit(data, 0);
return 1;
}

static int submit_arg(void *ptr, struct common_data_t *common)
{
const char *argp = 0;
bpf_probe_read_user(&argp, sizeof(argp), ptr);
if (argp) {
return __submit_arg((void *)(argp), common);
}
return 0;
}

static int enter_execve(const char *filename,
const char *const *argv,
const char *const *envp)
{
struct common_data_t common = {};

struct task_struct *task = (struct task_struct *)bpf_get_current_task();
u32 session_id = BPF_CORE_READ(task, sessionid);
u8 *is_monitored = bpf_map_lookup_elem(&monitored_sessionids, &session_id);
if (is_monitored == NULL) {
return 0;
}

print_command_event(task, filename, argv);

common.pid = bpf_get_current_pid_tgid() >> 32;
common.cgroup = bpf_get_current_cgroup_id();
common.audit_session_id = session_id;

common.ppid = BPF_CORE_READ(task, real_parent, tgid);
bpf_get_current_comm(&common.command, sizeof(common.command));

if(__submit_arg((void *)filename, &common) < 0) {
struct data_t *data = bpf_ringbuf_reserve(&execve_events, sizeof(*data), 0);
if (!data) {
INCR_COUNTER(lost);
goto out;
bpf_printk("execve_events ring buffer full");
return 0;
}

for (int i = 1; i < MAXARGS; i++) {
int res = submit_arg((void *)&argv[i], &common);
if (res < 0) {
INCR_COUNTER(lost);
goto out;
}

// If no arguments were sent, we reached the end of the arguments list.
if (res == 0)
goto out;
u64 filename_loc = BPF_CORE_READ(tp, __data_loc_filename) & 0xFFFF;
bpf_probe_read_str(&data->filename, sizeof(data->filename), (void *)tp + filename_loc);

void *arg_start = (void *)BPF_CORE_READ(task, mm, arg_start);
void *arg_end = (void *)BPF_CORE_READ(task, mm, arg_end);
data->args_len = arg_end - arg_start;

data->args_truncated = false;
if (data->args_len > ARGBUFSIZE) {
data->args_len = ARGBUFSIZE;
data->args_truncated = true;
}

// handle truncated argument list
char ellipsis[] = "...";
if (__submit_arg((void *)ellipsis, &common) < 0)
INCR_COUNTER(lost);
out:
return 0;
}

static int exit_execve(int ret)
{
struct task_struct *task = (struct task_struct *)bpf_get_current_task();
u32 session_id = BPF_CORE_READ(task, sessionid);
u8 *is_monitored = bpf_map_lookup_elem(&monitored_sessionids, &session_id);
if (is_monitored == NULL) {
return 0;
int read_ret = bpf_probe_read_user(&data->args, data->args_len, arg_start);
if (read_ret < 0) {
data->args_len = 0;
}

struct data_t *data = bpf_ringbuf_reserve(&execve_events, sizeof(*data), 0);
if (!data) {
INCR_COUNTER(lost);
return 0;
}
print_command_event(task, data->filename, data->args);

data->pid = bpf_get_current_pid_tgid() >> 32;
data->cgroup = bpf_get_current_cgroup_id();
data->audit_session_id = session_id;

task = (struct task_struct *)bpf_get_current_task();
data->ppid = BPF_CORE_READ(task, real_parent, tgid);

bpf_get_current_comm(&data->command, sizeof(data->command));
data->type = EVENT_RET;
data->retval = ret;

bpf_ringbuf_submit(data, 0);
return 0;
}

SEC("tp/syscalls/sys_execve")
int tracepoint__syscalls__sys_enter_execve(struct syscall_trace_enter *tp)
{
const char *filename = (const char *)tp->args[0];
const char *const *argv = (const char *const *)tp->args[1];
const char *const *envp = (const char *const *)tp->args[2];

return enter_execve(filename, argv, envp);
}

SEC("tp/syscalls/sys_exit_execve")
int tracepoint__syscalls__sys_exit_execve(struct syscall_trace_exit *tp)
{
return exit_execve(tp->ret);
}

SEC("tp/syscalls/sys_execveat")
int tracepoint__syscalls__sys_enter_execveat(struct syscall_trace_enter *tp)
{
const char *filename = (const char *)tp->args[1];
const char *const *argv = (const char *const *)tp->args[2];
const char *const *envp = (const char *const *)tp->args[3];

return enter_execve(filename, argv, envp);
return 0;
}

SEC("tp/syscalls/sys_exit_execveat")
int tracepoint__syscalls__sys_exit_execveat(struct syscall_trace_exit *tp)
SEC("tracepoint/sched/sched_process_exec")
int tracepoint__sched__sched_process_exec(struct trace_event_raw_sched_process_exec *tp)
{
return exit_execve(tp->ret);
return enter_execve(tp);
}
21 changes: 9 additions & 12 deletions bpf/enhancedrecording/common.h
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Original file line number Diff line number Diff line change
Expand Up @@ -11,9 +11,12 @@
// Maximum monitored sessions.
#define MAX_MONITORED_SESSIONS 1024

#define FILENAMESIZE 512

// ARGSIZE specifies the max argument size read.
#define ARGSIZE 1024
#define MAXARGS 20
#define _ARGSIZE 1024
#define _MAXARGS 20
#define ARGBUFSIZE (_ARGSIZE * _MAXARGS)

// Easier to use bpf_printk taken from https://nakryiko.com/posts/bpf-tips-printk/

Expand Down Expand Up @@ -49,19 +52,13 @@ static void print_event(struct task_struct *task) {
bpf_printk(" session ID: %lu", session_id);
}

static void print_command_event(struct task_struct *task, const char *filename, const char *const *argv) {
static void print_command_event(struct task_struct *task, const u8 filename[FILENAMESIZE], const u8 argv[ARGBUFSIZE]) {
const char *arg = NULL;

bpf_printk("command:");
print_event(task);
bpf_printk(" filename: %s", filename);
for (int i = 1; i < MAXARGS; i++) {
bpf_probe_read_user_str(&arg, MAXARGS, (void*)&argv[i]);
if (arg == NULL){
break;
}
bpf_printk(" argv[%d]: %s", i, arg);
}
bpf_printk(" argv[0]: %s", argv);
}

static void print_disk_event(struct task_struct *task, const char *path) {
Expand All @@ -72,7 +69,7 @@ static void print_disk_event(struct task_struct *task, const char *path) {
#else
#define bpf_printk(fmt, ...)
static void print_event(struct task_struct *task) {}
static void print_command_event(struct task_struct *task, const char *filename, const char *const *argv) {}
static void print_command_event(struct task_struct *task, const u8 filename[FILENAMESIZE], const u8 argv[ARGBUFSIZE]) {}
static void print_disk_event(struct task_struct *task, const char *path) {}
#endif

Expand Down
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