support disk events on Linux kernel 7.0+ by conditionally hooking do_file_open (#67650)

* support disk events on Linux kernel 7.0+ by conditionally hooking do_file_open

* default to do_file_open

bpf/enhancedrecording/disk.bpf.c

@@ -114,12 +114,12 @@ int BPF_PROG(security_file_open, struct file *f)
     return 0;
 }
 
-// do_filp_open is called for all file open syscalls, but we aren't
+// do_file_open is called for all file open syscalls, but we aren't
 // able to get a resolved path here. If opening failed early,
 // security_file_open will not be called so we fall back to using the
 // unresolved path in the emitted event.
-SEC("fexit/do_filp_open")
+SEC("fexit/do_file_open")
-int BPF_PROG(do_filp_open_exit, int dfd, struct filename *pathname, const struct open_flags *op, struct file *ret)
+int BPF_PROG(do_file_open_exit, int dfd, struct filename *pathname, const struct open_flags *op, struct file *ret)
 {
     struct task_struct *task = bpf_get_current_task_btf();
     u32 session_id = task->sessionid;

lib/bpf/disk.go

@@ -22,10 +22,12 @@ package bpf
 
 import (
 	"context"
+	"errors"
 	"io"
 	"sync"
 
 	"github.com/cilium/ebpf"
+	"github.com/cilium/ebpf/btf"
 	"github.com/cilium/ebpf/link"
 	"github.com/cilium/ebpf/ringbuf"
 	"github.com/cilium/ebpf/rlimit"
@@ -36,6 +38,11 @@ import (
 	"github.com/gravitational/teleport/lib/observability/metrics"
 )
 
+const (
+	doFilpOpenName = "do_filp_open"
+	doFileOpenName = "do_file_open"
+)
+
 var lostDiskEvents = prometheus.NewCounter(
 	prometheus.CounterOpts{
 		Name: teleport.MetricLostDiskEvents,
@@ -71,9 +78,28 @@ func startOpen(bufferSize int) (*open, error) {
 		return nil, trace.Wrap(err)
 	}
 
+	// The disk eBPF program hooks do_file_open by default, which was
+	// renamed from do_filp_open in 7.0. Check if do_file_open is available
+	// and use do_filp_open otherwise; don't rely on the kernel version.
+	attachTarget, err := findOpenAttachTarget()
+	if err != nil {
+		return nil, trace.Wrap(err)
+	}
+
 	var objs diskObjects
-	if err := loadDiskObjects(&objs, nil); err != nil {
+	spec, err := loadDisk()
-		return nil, trace.Wrap(err, "loading disk objects: %v", err)
+	if err != nil {
+		return nil, trace.Wrap(err, "reading disk objects")
+	}
+
+	p, ok := spec.Programs["do_file_open_exit"]
+	if !ok {
+		return nil, trace.NotFound("do_file_open_exit not found in disk objects")
+	}
+	p.AttachTo = attachTarget
+
+	if err := spec.LoadAndAssign(&objs, nil); err != nil {
+		return nil, trace.Wrap(err, "loading disk objects")
 	}
 
 	lostCtr, err := NewCounter(objs.LostCounter, objs.LostDoorbell, lostDiskEvents)
@@ -91,7 +117,7 @@ func startOpen(bufferSize int) (*open, error) {
 			attachType: ebpf.AttachTraceFEntry,
 		},
 		{
-			prog:       objs.DoFilpOpenExit,
+			prog:       objs.DoFileOpenExit,
 			attachType: ebpf.AttachTraceFExit,
 		},
 	}
@@ -124,6 +150,27 @@ func startOpen(bufferSize int) (*open, error) {
 	return o, nil
 }
 
+func findOpenAttachTarget() (string, error) {
+	kspec, err := btf.LoadKernelSpec()
+	if err != nil {
+		return "", trace.Wrap(err, "loading kernel BTF spec")
+	}
+
+	for _, target := range []string{doFileOpenName, doFilpOpenName} {
+		var fn *btf.Func
+		if err := kspec.TypeByName(target, &fn); err != nil {
+			if errors.Is(err, btf.ErrNotFound) {
+				continue
+			}
+			return "", trace.Wrap(err, "finding %s", target)
+		}
+
+		return target, nil
+	}
+
+	return "", trace.NotFound("do_file_open and do_filp_open not found in kernel BTF spec")
+}
+
 func (o *open) startSession(auditSessionID uint32) error {
 	o.mtx.Lock()
 	defer o.mtx.Unlock()

lib/bpf/disk_arm64_bpfel.go

@@ -67,7 +67,7 @@ type diskSpecs struct {
 //
 // It can be passed ebpf.CollectionSpec.Assign.
 type diskProgramSpecs struct {
-	DoFilpOpenExit   *ebpf.ProgramSpec `ebpf:"do_filp_open_exit"`
+	DoFileOpenExit   *ebpf.ProgramSpec `ebpf:"do_file_open_exit"`
 	SecurityFileOpen *ebpf.ProgramSpec `ebpf:"security_file_open"`
 }
 
@@ -137,13 +137,13 @@ type diskVariables struct {
 //
 // It can be passed to loadDiskObjects or ebpf.CollectionSpec.LoadAndAssign.
 type diskPrograms struct {
-	DoFilpOpenExit   *ebpf.Program `ebpf:"do_filp_open_exit"`
+	DoFileOpenExit   *ebpf.Program `ebpf:"do_file_open_exit"`
 	SecurityFileOpen *ebpf.Program `ebpf:"security_file_open"`
 }
 
 func (p *diskPrograms) Close() error {
 	return _DiskClose(
-		p.DoFilpOpenExit,
+		p.DoFileOpenExit,
 		p.SecurityFileOpen,
 	)
 }

lib/bpf/disk_x86_bpfel.go

@@ -67,7 +67,7 @@ type diskSpecs struct {
 //
 // It can be passed ebpf.CollectionSpec.Assign.
 type diskProgramSpecs struct {
-	DoFilpOpenExit   *ebpf.ProgramSpec `ebpf:"do_filp_open_exit"`
+	DoFileOpenExit   *ebpf.ProgramSpec `ebpf:"do_file_open_exit"`
 	SecurityFileOpen *ebpf.ProgramSpec `ebpf:"security_file_open"`
 }
 
@@ -137,13 +137,13 @@ type diskVariables struct {
 //
 // It can be passed to loadDiskObjects or ebpf.CollectionSpec.LoadAndAssign.
 type diskPrograms struct {
-	DoFilpOpenExit   *ebpf.Program `ebpf:"do_filp_open_exit"`
+	DoFileOpenExit   *ebpf.Program `ebpf:"do_file_open_exit"`
 	SecurityFileOpen *ebpf.Program `ebpf:"security_file_open"`
 }
 
 func (p *diskPrograms) Close() error {
 	return _DiskClose(
-		p.DoFilpOpenExit,
+		p.DoFileOpenExit,
 		p.SecurityFileOpen,
 	)
 }

lib/srv/bpf_test.go

@@ -1343,7 +1343,6 @@ func runCommand(t *testing.T, srv Server, bpfSrv bpf.BPF, command string, expect
 	scx.execRequest.SetCommand(command)
 
 	clientChan, serverChan := newMockSSHChannel(t)
-	clientChan.Drain()
 
 	t.Logf("running %q", command)
 
@@ -1399,7 +1398,7 @@ func runCommand(t *testing.T, srv Server, bpfSrv bpf.BPF, command string, expect
 
 		stdout := make([]byte, 1024)
 		for {
-			_, err := serverChan.Read(stdout)
+			_, err := clientChan.Read(stdout)
 			if err != nil {
 				if errors.Is(err, io.EOF) {
 					return