Fix simple mistakes identified by goreportcard.

These are primarily simplification and lint mistakes. However, minor
fixes are also included and tests added where appropriate.

PiperOrigin-RevId: 351425971

11 files changed, 23 insertions, 8 deletions

diff --git a/pkg/sentry/fs/fsutil/inode.go b/pkg/sentry/fs/fsutil/inode.go
index 1922ff08c..85e7e35db 100644
--- a/pkg/sentry/fs/fsutil/inode.go
+++ b/pkg/sentry/fs/fsutil/inode.go
@@ -510,6 +510,7 @@ func (InodeDenyWriteChecker) Check(ctx context.Context, inode *fs.Inode, p fs.Pe
 //InodeNotAllocatable can be used by Inodes that do not support Allocate().
 type InodeNotAllocatable struct{}
 
+// Allocate implements fs.InodeOperations.Allocate.
 func (InodeNotAllocatable) Allocate(_ context.Context, _ *fs.Inode, _, _ int64) error {
 	return syserror.EOPNOTSUPP
 }
diff --git a/pkg/sentry/fs/inode.go b/pkg/sentry/fs/inode.go
index 9b3d8166a..41a3c2047 100644
--- a/pkg/sentry/fs/inode.go
+++ b/pkg/sentry/fs/inode.go
@@ -367,6 +367,7 @@ func (i *Inode) Truncate(ctx context.Context, d *Dirent, size int64) error {
 	return i.InodeOperations.Truncate(ctx, i, size)
 }
 
+// Allocate calls i.InodeOperations.Allocate with i as the Inode.
 func (i *Inode) Allocate(ctx context.Context, d *Dirent, offset int64, length int64) error {
 	if i.overlay != nil {
 		return overlayAllocate(ctx, i.overlay, d, offset, length)
diff --git a/pkg/sentry/fsimpl/testutil/kernel.go b/pkg/sentry/fsimpl/testutil/kernel.go
index 205ad8192..807e4f44a 100644
--- a/pkg/sentry/fsimpl/testutil/kernel.go
+++ b/pkg/sentry/fsimpl/testutil/kernel.go
@@ -114,7 +114,7 @@ func Boot() (*kernel.Kernel, error) {
 		return nil, err
 	}
 	tg := k.NewThreadGroup(nil, k.RootPIDNamespace(), kernel.NewSignalHandlers(), linux.SIGCHLD, ls)
-	k.TestOnly_SetGlobalInit(tg)
+	k.TestOnlySetGlobalInit(tg)
 
 	return k, nil
 }
diff --git a/pkg/sentry/kernel/auth/id.go b/pkg/sentry/kernel/auth/id.go
index 4c32ee703..994486ea8 100644
--- a/pkg/sentry/kernel/auth/id.go
+++ b/pkg/sentry/kernel/auth/id.go
@@ -62,18 +62,28 @@ const (
 	// field is displayed as 4294967295 (-1 as an unsigned integer);" -
 	// user_namespaces(7)
 	OverflowUID = UID(65534)
+
+	// OverflowGID is the group equivalent to OverflowUID.
 	OverflowGID = GID(65534)
 
 	// NobodyKUID is the user ID usually reserved for the least privileged user
 	// "nobody".
 	NobodyKUID = KUID(65534)
+
+	// NobodyKGID is the group equivalent to NobodyKUID.
 	NobodyKGID = KGID(65534)
 
 	// RootKUID is the user ID usually used for the most privileged user "root".
 	RootKUID = KUID(0)
+
+	// RootKGID is the group equivalent to RootKUID.
 	RootKGID = KGID(0)
-	RootUID  = UID(0)
-	RootGID  = GID(0)
+
+	// RootUID is the root user.
+	RootUID = UID(0)
+
+	// RootGID is the root group.
+	RootGID = GID(0)
 )
 
 // Ok returns true if uid is not -1.
diff --git a/pkg/sentry/kernel/kernel.go b/pkg/sentry/kernel/kernel.go
index b8627a54f..303ae8056 100644
--- a/pkg/sentry/kernel/kernel.go
+++ b/pkg/sentry/kernel/kernel.go
@@ -1433,8 +1433,8 @@ func (k *Kernel) GlobalInit() *ThreadGroup {
 	return k.globalInit
 }
 
-// TestOnly_SetGlobalInit sets the thread group with ID 1 in the root PID namespace.
-func (k *Kernel) TestOnly_SetGlobalInit(tg *ThreadGroup) {
+// TestOnlySetGlobalInit sets the thread group with ID 1 in the root PID namespace.
+func (k *Kernel) TestOnlySetGlobalInit(tg *ThreadGroup) {
 	k.globalInit = tg
 }
 
diff --git a/pkg/sentry/platform/ring0/kernel_amd64.go b/pkg/sentry/platform/ring0/kernel_amd64.go
index b55dc29b3..36a60700e 100644
--- a/pkg/sentry/platform/ring0/kernel_amd64.go
+++ b/pkg/sentry/platform/ring0/kernel_amd64.go
@@ -65,6 +65,7 @@ func (k *Kernel) init(maxCPUs int) {
 	}
 }
 
+// EntryRegions returns the set of kernel entry regions (must be mapped).
 func (k *Kernel) EntryRegions() map[uintptr]uintptr {
 	regions := make(map[uintptr]uintptr)
 
diff --git a/pkg/sentry/socket/netfilter/netfilter.go b/pkg/sentry/socket/netfilter/netfilter.go
index b283d7229..26bd1abd4 100644
--- a/pkg/sentry/socket/netfilter/netfilter.go
+++ b/pkg/sentry/socket/netfilter/netfilter.go
@@ -205,7 +205,7 @@ func SetEntries(stk *stack.Stack, optVal []byte, ipv6 bool) *syserr.Error {
 
 	// Go through the list of supported hooks for this table and, for each
 	// one, set the rule it corresponds to.
-	for hook, _ := range replace.HookEntry {
+	for hook := range replace.HookEntry {
 		if table.ValidHooks()&(1<<hook) != 0 {
 			hk := hookFromLinux(hook)
 			table.BuiltinChains[hk] = stack.HookUnset
diff --git a/pkg/sentry/socket/netfilter/owner_matcher.go b/pkg/sentry/socket/netfilter/owner_matcher.go
index 1b4e0ad79..69d13745e 100644
--- a/pkg/sentry/socket/netfilter/owner_matcher.go
+++ b/pkg/sentry/socket/netfilter/owner_matcher.go
@@ -96,6 +96,7 @@ func (ownerMarshaler) unmarshal(buf []byte, filter stack.IPHeaderFilter) (stack.
 	return &owner, nil
 }
 
+// OwnerMatcher matches against a UID and/or GID.
 type OwnerMatcher struct {
 	uid       uint32
 	gid       uint32
diff --git a/pkg/sentry/socket/unix/unix.go b/pkg/sentry/socket/unix/unix.go
index c59297c80..6c4ec55b2 100644
--- a/pkg/sentry/socket/unix/unix.go
+++ b/pkg/sentry/socket/unix/unix.go
@@ -471,7 +471,7 @@ func (s *socketOpsCommon) SendMsg(t *kernel.Task, src usermem.IOSequence, to []b
 	if len(to) > 0 {
 		switch s.stype {
 		case linux.SOCK_SEQPACKET:
-			to = nil
+			// to is ignored.
 		case linux.SOCK_STREAM:
 			if s.State() == linux.SS_CONNECTED {
 				return 0, syserr.ErrAlreadyConnected
diff --git a/pkg/sentry/syscalls/linux/sys_sync.go b/pkg/sentry/syscalls/linux/sys_sync.go
index 048a21c6e..5ebd4461f 100644
--- a/pkg/sentry/syscalls/linux/sys_sync.go
+++ b/pkg/sentry/syscalls/linux/sys_sync.go
@@ -125,6 +125,7 @@ func SyncFileRange(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel
 	//
 	// It should be safe to skipped this flag while nobody uses
 	// SYNC_FILE_RANGE_WAIT_BEFORE.
+	_ = nbytes
 
 	// SYNC_FILE_RANGE_WAIT_AFTER waits upon write-out of all pages in the
 	// range after performing any write.
diff --git a/pkg/sentry/vfs/inotify.go b/pkg/sentry/vfs/inotify.go
index 107171b61..a48ac1cd6 100644
--- a/pkg/sentry/vfs/inotify.go
+++ b/pkg/sentry/vfs/inotify.go
@@ -738,7 +738,7 @@ func InotifyEventFromStatMask(mask uint32) uint32 {
 	} else if mask&linux.STATX_ATIME != 0 {
 		ev |= linux.IN_ACCESS
 	} else if mask&linux.STATX_MTIME != 0 {
-		mask |= linux.IN_MODIFY
+		ev |= linux.IN_MODIFY
 	}
 	return ev
 }