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feat(ebpf): make mem_prot_alert not rely on sys_enter/exit #4227

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Merged
merged 1 commit into from
Aug 13, 2024
Merged

feat(ebpf): make mem_prot_alert not rely on sys_enter/exit #4227

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30 changes: 14 additions & 16 deletions pkg/ebpf/c/tracee.bpf.c
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Original file line number Diff line number Diff line change
Expand Up @@ -3416,18 +3416,16 @@ int BPF_KPROBE(trace_mmap_alert)
if (!evaluate_scope_filters(&p))
return 0;

// Load the arguments given to the mmap syscall (which eventually invokes this function)
syscall_data_t *sys = &p.task_info->syscall_data;
if (!p.task_info->syscall_traced || sys->id != SYSCALL_MMAP)
if (p.event->context.syscall != SYSCALL_MMAP)
return 0;

int prot = sys->args.args[2];

struct pt_regs *task_regs = get_current_task_pt_regs();
int prot = get_syscall_arg3(p.event->task, task_regs, false);
if ((prot & (VM_WRITE | VM_EXEC)) == (VM_WRITE | VM_EXEC)) {
u32 alert = ALERT_MMAP_W_X;
int fd = sys->args.args[4];
void *addr = (void *) sys->args.args[0];
size_t len = sys->args.args[1];
void *addr = (void *) get_syscall_arg1(p.event->task, task_regs, false);
size_t len = get_syscall_arg2(p.event->task, task_regs, false);
int fd = get_syscall_arg5(p.event->task, task_regs, false);
int prev_prot = 0;
file_info_t file_info = {.pathname_p = NULL};
if (fd >= 0) {
Expand Down Expand Up @@ -3562,18 +3560,18 @@ int BPF_KPROBE(trace_security_file_mprotect)
if (!init_program_data(&p, ctx, SECURITY_FILE_MPROTECT))
return 0;

// Load the arguments given to the mprotect syscall (which eventually invokes this function)
syscall_data_t *sys = &p.task_info->syscall_data;
if (!p.task_info->syscall_traced ||
(sys->id != SYSCALL_MPROTECT && sys->id != SYSCALL_PKEY_MPROTECT))
if (p.event->context.syscall != SYSCALL_MPROTECT &&
p.event->context.syscall != SYSCALL_PKEY_MPROTECT)
return 0;

struct vm_area_struct *vma = (struct vm_area_struct *) PT_REGS_PARM1(ctx);
unsigned long reqprot = PT_REGS_PARM2(ctx);
unsigned long prev_prot = get_vma_flags(vma);
struct file *file = (struct file *) BPF_CORE_READ(vma, vm_file);
void *addr = (void *) sys->args.args[0];
size_t len = sys->args.args[1];

struct pt_regs *task_regs = get_current_task_pt_regs();
void *addr = (void *) get_syscall_arg1(p.event->task, task_regs, false);
size_t len = get_syscall_arg2(p.event->task, task_regs, false);

if (evaluate_scope_filters(&p)) {
file_info = get_file_info(file);
Expand All @@ -3585,8 +3583,8 @@ int BPF_KPROBE(trace_security_file_mprotect)
save_to_submit_buf(&p.event->args_buf, &addr, sizeof(void *), 4);
save_to_submit_buf(&p.event->args_buf, &len, sizeof(size_t), 5);

if (sys->id == SYSCALL_PKEY_MPROTECT) {
int pkey = sys->args.args[3];
if (p.event->context.syscall == SYSCALL_PKEY_MPROTECT) {
int pkey = get_syscall_arg4(p.event->task, task_regs, false);
save_to_submit_buf(&p.event->args_buf, &pkey, sizeof(int), 6);
}

Expand Down
8 changes: 0 additions & 8 deletions pkg/events/core.go
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Original file line number Diff line number Diff line change
Expand Up @@ -11347,14 +11347,6 @@ var CoreEvents = map[ID]Definition{
probes: []Probe{
{handle: probes.SecurityMmapAddr, required: true},
{handle: probes.SecurityFileMProtect, required: true},
{handle: probes.SyscallEnter__Internal, required: true},
},
tailCalls: []TailCall{
{
"sys_enter_init_tail",
"sys_enter_init",
[]uint32{uint32(Mmap), uint32(Mprotect), uint32(PkeyMprotect)},
},
},
},
sets: []string{},
Expand Down