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tetragon: Factor uprobe sensor setup #2085

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merged 2 commits into from
Feb 12, 2024
Merged

tetragon: Factor uprobe sensor setup #2085

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f249b78
tetragon: Factor uprobe sensor setup
olsajiri Jan 30, 2024
6ca6feb
tetragon: Return zero in generic probe programs
olsajiri Dec 27, 2023
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6 changes: 3 additions & 3 deletions bpf/process/types/basic.h
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Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -2375,7 +2375,7 @@ filter_read_arg(void *ctx, struct bpf_map_def *heap,
}

tail_call(ctx, tailcalls, TAIL_CALL_SEND);
return 1;
return 0;
}

static inline __attribute__((always_inline)) long
Expand Down Expand Up @@ -2417,7 +2417,7 @@ generic_actions(void *ctx, struct bpf_map_def *heap,
postit = do_actions(ctx, e, actions, override_tasks);
if (postit)
tail_call(ctx, tailcalls, TAIL_CALL_SEND);
return 1;
return 0;
}

static inline __attribute__((always_inline)) long
Expand Down Expand Up @@ -2468,7 +2468,7 @@ generic_output(void *ctx, struct bpf_map_def *heap, u8 op)
: [total] "+r"(total)
:);
perf_event_output_metric(ctx, op, &tcpmon_map, BPF_F_CURRENT_CPU, e, total);
return 1;
return 0;
}

/**
Expand Down
253 changes: 150 additions & 103 deletions pkg/sensors/tracing/genericuprobe.go
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Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -170,136 +170,183 @@ func isValidUprobeSelectors(selectors []v1alpha1.KProbeSelector) error {
return nil
}

type addUprobeIn struct {
sensorPath string
policyName string
}

func createGenericUprobeSensor(
name string,
uprobes []v1alpha1.UProbeSpec,
policyName string,
) (*sensors.Sensor, error) {
var progs []*program.Program
var maps []*program.Map
var ids []idtable.EntryID
var err error

sensorPath := name

loadProgName := "bpf_generic_uprobe.o"
if kernels.EnableV61Progs() {
loadProgName = "bpf_generic_uprobe_v61.o"
} else if kernels.EnableLargeProgs() {
loadProgName = "bpf_generic_uprobe_v53.o"
in := addUprobeIn{
sensorPath: name,
policyName: policyName,
}

for _, spec := range uprobes {
var args []v1alpha1.KProbeArg

if err := isValidUprobeSelectors(spec.Selectors); err != nil {
ids, err = addUprobe(&spec, ids, &in)
if err != nil {
return nil, err
}
}

progs, maps, err = createSingleUprobeSensor(ids)
if err != nil {
return nil, err
}

// Parse Filters into kernel filter logic
uprobeSelectorState, err := selectors.InitKernelSelectorState(spec.Selectors, args, nil, nil, nil)
return &sensors.Sensor{
Name: name,
Progs: progs,
Maps: maps,
}, nil
}

func addUprobe(spec *v1alpha1.UProbeSpec, ids []idtable.EntryID, in *addUprobeIn) ([]idtable.EntryID, error) {
var args []v1alpha1.KProbeArg

if err := isValidUprobeSelectors(spec.Selectors); err != nil {
return nil, err
}

// Parse Filters into kernel filter logic
uprobeSelectorState, err := selectors.InitKernelSelectorState(spec.Selectors, args, nil, nil, nil)
if err != nil {
return nil, err
}

msgField, err := getPolicyMessage(spec.Message)
if errors.Is(err, ErrMsgSyntaxShort) || errors.Is(err, ErrMsgSyntaxEscape) {
return nil, err
} else if errors.Is(err, ErrMsgSyntaxLong) {
logger.GetLogger().WithField("policy-name", in.policyName).
Warnf("TracingPolicy 'message' field too long, truncated to %d characters", TpMaxMessageLen)
}

var (
argTypes [api.EventConfigMaxArgs]int32
argMeta [api.EventConfigMaxArgs]uint32
argSet [api.EventConfigMaxArgs]bool

argPrinters []argPrinter
)

// Parse Arguments
for i, a := range spec.Args {
argType := gt.GenericTypeFromString(a.Type)
if argType == gt.GenericInvalidType {
return nil, fmt.Errorf("Arg(%d) type '%s' unsupported", i, a.Type)
}
argMValue, err := getMetaValue(&a)
if err != nil {
return nil, err
}
if a.Index > 4 {
return nil, fmt.Errorf("Error add arg: ArgType %s Index %d out of bounds",
a.Type, int(a.Index))
}
argTypes[a.Index] = int32(argType)
argMeta[a.Index] = uint32(argMValue)
argSet[a.Index] = true

msgField, err := getPolicyMessage(spec.Message)
if errors.Is(err, ErrMsgSyntaxShort) || errors.Is(err, ErrMsgSyntaxEscape) {
return nil, err
} else if errors.Is(err, ErrMsgSyntaxLong) {
logger.GetLogger().WithField("policy-name", policyName).Warnf("TracingPolicy 'message' field too long, truncated to %d characters", TpMaxMessageLen)
argPrinters = append(argPrinters, argPrinter{index: i, ty: argType})
}

// Mark remaining arguments as 'nops' the kernel side will skip
// copying 'nop' args.
for i, a := range argSet {
if !a {
argTypes[i] = gt.GenericNopType
argMeta[i] = 0
}
}

var (
argTypes [api.EventConfigMaxArgs]int32
argMeta [api.EventConfigMaxArgs]uint32
argSet [api.EventConfigMaxArgs]bool

argPrinters []argPrinter
)

// Parse Arguments
for i, a := range spec.Args {
argType := gt.GenericTypeFromString(a.Type)
if argType == gt.GenericInvalidType {
return nil, fmt.Errorf("Arg(%d) type '%s' unsupported", i, a.Type)
}
argMValue, err := getMetaValue(&a)
if err != nil {
return nil, err
}
if a.Index > 4 {
return nil, fmt.Errorf("Error add arg: ArgType %s Index %d out of bounds",
a.Type, int(a.Index))
}
argTypes[a.Index] = int32(argType)
argMeta[a.Index] = uint32(argMValue)
argSet[a.Index] = true

argPrinters = append(argPrinters, argPrinter{index: i, ty: argType})
for _, sym := range spec.Symbols {
config := &api.EventConfig{
Arg: argTypes,
ArgM: argMeta,
}

// Mark remaining arguments as 'nops' the kernel side will skip
// copying 'nop' args.
for i, a := range argSet {
if !a {
argTypes[i] = gt.GenericNopType
argMeta[i] = 0
}
uprobeEntry := &genericUprobe{
tableId: idtable.UninitializedEntryID,
config: config,
path: spec.Path,
symbol: sym,
selectors: uprobeSelectorState,
policyName: in.policyName,
message: msgField,
argPrinters: argPrinters,
}

for _, sym := range spec.Symbols {
config := &api.EventConfig{
Arg: argTypes,
ArgM: argMeta,
}

uprobeEntry := &genericUprobe{
tableId: idtable.UninitializedEntryID,
config: config,
path: spec.Path,
symbol: sym,
selectors: uprobeSelectorState,
policyName: policyName,
message: msgField,
argPrinters: argPrinters,
}

uprobeTable.AddEntry(uprobeEntry)
id := uprobeEntry.tableId.ID

uprobeEntry.pinPathPrefix = sensors.PathJoin(sensorPath, fmt.Sprintf("%d", id))
config.FuncId = uint32(id)

pinPath := uprobeEntry.pinPathPrefix
pinProg := sensors.PathJoin(pinPath, "prog")

attachData := &program.UprobeAttachData{
Path: spec.Path,
Symbol: sym,
}

load := program.Builder(
path.Join(option.Config.HubbleLib, loadProgName),
"",
"uprobe/generic_uprobe",
pinProg,
"generic_uprobe").
SetAttachData(attachData).
SetLoaderData(uprobeEntry)

progs = append(progs, load)

configMap := program.MapBuilderPin("config_map", sensors.PathJoin(pinPath, "config_map"), load)
tailCalls := program.MapBuilderPin("uprobe_calls", sensors.PathJoin(pinPath, "up_calls"), load)
filterMap := program.MapBuilderPin("filter_map", sensors.PathJoin(pinPath, "filter_map"), load)
selMatchBinariesMap := program.MapBuilderPin("tg_mb_sel_opts", sensors.PathJoin(pinPath, "tg_mb_sel_opts"), load)
maps = append(maps, configMap, tailCalls, filterMap, selMatchBinariesMap)
uprobeTable.AddEntry(uprobeEntry)
id := uprobeEntry.tableId

uprobeEntry.pinPathPrefix = sensors.PathJoin(in.sensorPath, fmt.Sprintf("%d", id.ID))
config.FuncId = uint32(id.ID)

ids = append(ids, id)
}

return ids, nil
}

func createSingleUprobeSensor(ids []idtable.EntryID) ([]*program.Program, []*program.Map, error) {
var progs []*program.Program
var maps []*program.Map

for _, id := range ids {
uprobeEntry, err := genericUprobeTableGet(id)
if err != nil {
return nil, nil, err
}
progs, maps = createUprobeSensorFromEntry(uprobeEntry, progs, maps)
}

return &sensors.Sensor{
Name: name,
Progs: progs,
Maps: maps,
}, nil
return progs, maps, nil
}

func createUprobeSensorFromEntry(uprobeEntry *genericUprobe,
progs []*program.Program, maps []*program.Map) ([]*program.Program, []*program.Map) {

loadProgName := "bpf_generic_uprobe.o"
if kernels.EnableV61Progs() {
loadProgName = "bpf_generic_uprobe_v61.o"
} else if kernels.EnableLargeProgs() {
loadProgName = "bpf_generic_uprobe_v53.o"
}

pinPath := uprobeEntry.pinPathPrefix
pinProg := sensors.PathJoin(pinPath, "prog")

attachData := &program.UprobeAttachData{
Path: uprobeEntry.path,
Symbol: uprobeEntry.symbol,
}

load := program.Builder(
path.Join(option.Config.HubbleLib, loadProgName),
"",
"uprobe/generic_uprobe",
pinProg,
"generic_uprobe").
SetAttachData(attachData).
SetLoaderData(uprobeEntry)

progs = append(progs, load)

configMap := program.MapBuilderPin("config_map", sensors.PathJoin(pinPath, "config_map"), load)
tailCalls := program.MapBuilderPin("uprobe_calls", sensors.PathJoin(pinPath, "up_calls"), load)
filterMap := program.MapBuilderPin("filter_map", sensors.PathJoin(pinPath, "filter_map"), load)
selMatchBinariesMap := program.MapBuilderPin("tg_mb_sel_opts", sensors.PathJoin(pinPath, "tg_mb_sel_opts"), load)
maps = append(maps, configMap, tailCalls, filterMap, selMatchBinariesMap)
return progs, maps
}

func (k *observerUprobeSensor) PolicyHandler(
Expand Down
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