tracing: ensure strings are valid utf-8

[ upstream commit 7c7ed6a ] Kprobe arguments that include strings are generated using handleGenericKprobeString. Because protobufs only support strings that are valid utf-8, we need to ensure that the strings we get from bpf are valid utf-8. Also, ensure that Path in loader is valid utf-8. Signed-off-by: Kornilios Kourtis <[email protected]>
cilium · Jul 28, 2023 · b1937f1 · b1937f1
1 parent 7c1c7d1
commit b1937f1
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Showing 2 changed files with 4 additions and 2 deletions.
diff --git a/pkg/sensors/tracing/generickprobe.go b/pkg/sensors/tracing/generickprobe.go
@@ -34,6 +34,7 @@ import (
 	"github.com/cilium/tetragon/pkg/sensors"
 	"github.com/cilium/tetragon/pkg/sensors/base"
 	"github.com/cilium/tetragon/pkg/sensors/program"
+	"github.com/cilium/tetragon/pkg/strutils"
 	lru "github.com/hashicorp/golang-lru/v2"
 	"github.com/sirupsen/logrus"
 
@@ -739,7 +740,7 @@ func handleGenericKprobeString(r *bytes.Reader, def string) string {
 		return def
 	}
 
-	strVal := string(outputStr[:])
+	strVal := strutils.UTF8FromBPFBytes(outputStr[:])
 	lenStrVal := len(strVal)
 	if lenStrVal > 0 && strVal[lenStrVal-1] == '\x00' {
 		strVal = strVal[0 : lenStrVal-1]

diff --git a/pkg/sensors/tracing/loader.go b/pkg/sensors/tracing/loader.go
@@ -42,6 +42,7 @@ import (
 	"github.com/cilium/tetragon/pkg/policyfilter"
 	"github.com/cilium/tetragon/pkg/sensors"
 	"github.com/cilium/tetragon/pkg/sensors/program"
+	"github.com/cilium/tetragon/pkg/strutils"
 	"github.com/cilium/tetragon/pkg/tracingpolicy"
 	"golang.org/x/sys/unix"
 )
@@ -168,7 +169,7 @@ func handleLoader(r *bytes.Reader) ([]observer.Event, error) {
 	msg := &tracing.MsgProcessLoaderUnix{
 		ProcessKey: m.ProcessKey,
 		Ktime:      m.Common.Ktime,
-		Path:       string(path),
+		Path:       strutils.UTF8FromBPFBytes(path),
 		Buildid:    m.BuildId[:m.BuildIdSize],
 	}
 	return []observer.Event{msg}, nil