From 6258291815e823034218fc617c3fc70978d7137b Mon Sep 17 00:00:00 2001
From: Fabricio Voznika <fvoznika@google.com>
Date: Wed, 15 Jun 2022 13:37:13 -0700
Subject: [PATCH] Small fixes to trace points

Don't collect `cwd` when task root is not present anymore, e.g. zombie.
Limit the size allocated for address in `connect(2)`.

Updates #4805

PiperOrigin-RevId: 455208465
---
 pkg/sentry/kernel/seccheck.go       | 14 ++++++++------
 pkg/sentry/syscalls/linux/points.go |  5 +----
 2 files changed, 9 insertions(+), 10 deletions(-)

diff --git a/pkg/sentry/kernel/seccheck.go b/pkg/sentry/kernel/seccheck.go
index 9afb7c130..9d680235e 100644
--- a/pkg/sentry/kernel/seccheck.go
+++ b/pkg/sentry/kernel/seccheck.go
@@ -49,12 +49,14 @@ func LoadSeccheckDataLocked(t *Task, mask seccheck.FieldMask, info *pb.ContextDa
 		info.ContainerId = t.tg.leader.ContainerID()
 	}
 	if mask.Contains(seccheck.FieldCtxtCwd) {
-		root := t.FSContext().RootDirectoryVFS2()
-		defer root.DecRef(t)
-		wd := t.FSContext().WorkingDirectoryVFS2()
-		defer wd.DecRef(t)
-		vfsObj := root.Mount().Filesystem().VirtualFilesystem()
-		info.Cwd, _ = vfsObj.PathnameWithDeleted(t, root, wd)
+		if root := t.FSContext().RootDirectoryVFS2(); root.Ok() {
+			defer root.DecRef(t)
+			if wd := t.FSContext().WorkingDirectoryVFS2(); wd.Ok() {
+				defer wd.DecRef(t)
+				vfsObj := root.Mount().Filesystem().VirtualFilesystem()
+				info.Cwd, _ = vfsObj.PathnameWithDeleted(t, root, wd)
+			}
+		}
 	}
 	if mask.Contains(seccheck.FieldCtxtProcessName) {
 		info.ProcessName = t.Name()
diff --git a/pkg/sentry/syscalls/linux/points.go b/pkg/sentry/syscalls/linux/points.go
index bedfeb899..6b7a3956c 100644
--- a/pkg/sentry/syscalls/linux/points.go
+++ b/pkg/sentry/syscalls/linux/points.go
@@ -191,10 +191,7 @@ func PointConnect(t *kernel.Task, fields seccheck.FieldSet, cxtData *pb.ContextD
 
 	addr := info.Args[1].Pointer()
 	addrlen := info.Args[2].Uint()
-	if addr > 0 {
-		p.Address = make([]byte, addrlen)
-		_, _ = t.CopyInBytes(addr, p.Address)
-	}
+	p.Address, _ = CaptureAddress(t, addr, addrlen)
 
 	if fields.Local.Contains(seccheck.FieldSyscallPath) {
 		p.FdPath = getFilePath(t, int32(p.Fd))