Merge release-20200810.0-236-gb8bee78d0 (automated)

6 files changed, 40 insertions, 68 deletions

diff --git a/pkg/sentry/vfs/file_description_impl_util.go b/pkg/sentry/vfs/file_description_impl_util.go
index 68b80a951..2b668fd89 100644
--- a/pkg/sentry/vfs/file_description_impl_util.go
+++ b/pkg/sentry/vfs/file_description_impl_util.go
@@ -107,7 +107,7 @@ func (FileDescriptionDefaultImpl) Write(ctx context.Context, src usermem.IOSeque
 // file_operations::iterate == file_operations::iterate_shared == NULL in
 // Linux.
 func (FileDescriptionDefaultImpl) IterDirents(ctx context.Context, cb IterDirentsCallback) error {
-	return syserror.ENOTDIR
+	return syserror.ENOSYS
 }
 
 // Seek implements FileDescriptionImpl.Seek analogously to
diff --git a/pkg/sentry/vfs/file_description_refs.go b/pkg/sentry/vfs/file_description_refs.go
index ebc089b4c..bdd7e6554 100644
--- a/pkg/sentry/vfs/file_description_refs.go
+++ b/pkg/sentry/vfs/file_description_refs.go
@@ -1,12 +1,12 @@
 package vfs
 
 import (
+	"fmt"
+	"runtime"
 	"sync/atomic"
 
-	"fmt"
 	"gvisor.dev/gvisor/pkg/log"
 	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
-	"runtime"
 )
 
 // ownerType is used to customize logging. Note that we use a pointer to T so
diff --git a/pkg/sentry/vfs/filesystem_refs.go b/pkg/sentry/vfs/filesystem_refs.go
index 32f21c044..38a9a986f 100644
--- a/pkg/sentry/vfs/filesystem_refs.go
+++ b/pkg/sentry/vfs/filesystem_refs.go
@@ -1,12 +1,12 @@
 package vfs
 
 import (
+	"fmt"
+	"runtime"
 	"sync/atomic"
 
-	"fmt"
 	"gvisor.dev/gvisor/pkg/log"
 	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
-	"runtime"
 )
 
 // ownerType is used to customize logging. Note that we use a pointer to T so
diff --git a/pkg/sentry/vfs/mount.go b/pkg/sentry/vfs/mount.go
index 9da09d4c1..06ca91989 100644
--- a/pkg/sentry/vfs/mount.go
+++ b/pkg/sentry/vfs/mount.go
@@ -18,12 +18,14 @@ import (
 	"bytes"
 	"fmt"
 	"math"
+	"path"
 	"sort"
 	"strings"
 	"sync/atomic"
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/fspath"
 	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
 	"gvisor.dev/gvisor/pkg/syserror"
 )
@@ -738,23 +740,11 @@ func (mntns *MountNamespace) Root() VirtualDentry {
 //
 // Preconditions: taskRootDir.Ok().
 func (vfs *VirtualFilesystem) GenerateProcMounts(ctx context.Context, taskRootDir VirtualDentry, buf *bytes.Buffer) {
-	rootMnt := taskRootDir.mount
-
 	vfs.mountMu.Lock()
+	defer vfs.mountMu.Unlock()
+	rootMnt := taskRootDir.mount
 	mounts := rootMnt.submountsLocked()
-	// Take a reference on mounts since we need to drop vfs.mountMu before
-	// calling vfs.PathnameReachable() (=> FilesystemImpl.PrependPath()).
-	for _, mnt := range mounts {
-		mnt.IncRef()
-	}
-	vfs.mountMu.Unlock()
-	defer func() {
-		for _, mnt := range mounts {
-			mnt.DecRef(ctx)
-		}
-	}()
 	sort.Slice(mounts, func(i, j int) bool { return mounts[i].ID < mounts[j].ID })
-
 	for _, mnt := range mounts {
 		// Get the path to this mount relative to task root.
 		mntRootVD := VirtualDentry{
@@ -765,7 +755,7 @@ func (vfs *VirtualFilesystem) GenerateProcMounts(ctx context.Context, taskRootDi
 		if err != nil {
 			// For some reason we didn't get a path. Log a warning
 			// and run with empty path.
-			ctx.Warningf("VFS.GenerateProcMounts: error getting pathname for mount root %+v: %v", mnt.root, err)
+			ctx.Warningf("Error getting pathname for mount root %+v: %v", mnt.root, err)
 			path = ""
 		}
 		if path == "" {
@@ -799,25 +789,11 @@ func (vfs *VirtualFilesystem) GenerateProcMounts(ctx context.Context, taskRootDi
 //
 // Preconditions: taskRootDir.Ok().
 func (vfs *VirtualFilesystem) GenerateProcMountInfo(ctx context.Context, taskRootDir VirtualDentry, buf *bytes.Buffer) {
-	rootMnt := taskRootDir.mount
-
 	vfs.mountMu.Lock()
+	defer vfs.mountMu.Unlock()
+	rootMnt := taskRootDir.mount
 	mounts := rootMnt.submountsLocked()
-	// Take a reference on mounts since we need to drop vfs.mountMu before
-	// calling vfs.PathnameReachable() (=> FilesystemImpl.PrependPath()) or
-	// vfs.StatAt() (=> FilesystemImpl.StatAt()).
-	for _, mnt := range mounts {
-		mnt.IncRef()
-	}
-	vfs.mountMu.Unlock()
-	defer func() {
-		for _, mnt := range mounts {
-			mnt.DecRef(ctx)
-		}
-	}()
 	sort.Slice(mounts, func(i, j int) bool { return mounts[i].ID < mounts[j].ID })
-
-	creds := auth.CredentialsFromContext(ctx)
 	for _, mnt := range mounts {
 		// Get the path to this mount relative to task root.
 		mntRootVD := VirtualDentry{
@@ -828,7 +804,7 @@ func (vfs *VirtualFilesystem) GenerateProcMountInfo(ctx context.Context, taskRoo
 		if err != nil {
 			// For some reason we didn't get a path. Log a warning
 			// and run with empty path.
-			ctx.Warningf("VFS.GenerateProcMountInfo: error getting pathname for mount root %+v: %v", mnt.root, err)
+			ctx.Warningf("Error getting pathname for mount root %+v: %v", mnt.root, err)
 			path = ""
 		}
 		if path == "" {
@@ -841,10 +817,9 @@ func (vfs *VirtualFilesystem) GenerateProcMountInfo(ctx context.Context, taskRoo
 			Root:  mntRootVD,
 			Start: mntRootVD,
 		}
-		statx, err := vfs.StatAt(ctx, creds, pop, &StatOptions{})
+		statx, err := vfs.StatAt(ctx, auth.NewAnonymousCredentials(), pop, &StatOptions{})
 		if err != nil {
 			// Well that's not good. Ignore this mount.
-			ctx.Warningf("VFS.GenerateProcMountInfo: failed to stat mount root %+v: %v", mnt.root, err)
 			break
 		}
 
@@ -856,9 +831,6 @@ func (vfs *VirtualFilesystem) GenerateProcMountInfo(ctx context.Context, taskRoo
 		fmt.Fprintf(buf, "%d ", mnt.ID)
 
 		// (2)  Parent ID (or this ID if there is no parent).
-		// Note that even if the call to mnt.parent() races with Mount
-		// destruction (which is possible since we're not holding vfs.mountMu),
-		// its Mount.ID will still be valid.
 		pID := mnt.ID
 		if p := mnt.parent(); p != nil {
 			pID = p.ID
@@ -907,6 +879,30 @@ func (vfs *VirtualFilesystem) GenerateProcMountInfo(ctx context.Context, taskRoo
 	}
 }
 
+// MakeSyntheticMountpoint creates parent directories of target if they do not
+// exist and attempts to create a directory for the mountpoint. If a
+// non-directory file already exists there then we allow it.
+func (vfs *VirtualFilesystem) MakeSyntheticMountpoint(ctx context.Context, target string, root VirtualDentry, creds *auth.Credentials) error {
+	mkdirOpts := &MkdirOptions{Mode: 0777, ForSyntheticMountpoint: true}
+
+	// Make sure the parent directory of target exists.
+	if err := vfs.MkdirAllAt(ctx, path.Dir(target), root, creds, mkdirOpts); err != nil {
+		return fmt.Errorf("failed to create parent directory of mountpoint %q: %w", target, err)
+	}
+
+	// Attempt to mkdir the final component. If a file (of any type) exists
+	// then we let allow mounting on top of that because we do not require the
+	// target to be an existing directory, unlike Linux mount(2).
+	if err := vfs.MkdirAt(ctx, creds, &PathOperation{
+		Root:  root,
+		Start: root,
+		Path:  fspath.Parse(target),
+	}, mkdirOpts); err != nil && err != syserror.EEXIST {
+		return fmt.Errorf("failed to create mountpoint %q: %w", target, err)
+	}
+	return nil
+}
+
 // manglePath replaces ' ', '\t', '\n', and '\\' with their octal equivalents.
 // See Linux fs/seq_file.c:mangle_path.
 func manglePath(p string) string {
diff --git a/pkg/sentry/vfs/mount_namespace_refs.go b/pkg/sentry/vfs/mount_namespace_refs.go
index 2c920ac41..63285fb8e 100644
--- a/pkg/sentry/vfs/mount_namespace_refs.go
+++ b/pkg/sentry/vfs/mount_namespace_refs.go
@@ -1,12 +1,12 @@
 package vfs
 
 import (
+	"fmt"
+	"runtime"
 	"sync/atomic"
 
-	"fmt"
 	"gvisor.dev/gvisor/pkg/log"
 	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
-	"runtime"
 )
 
 // ownerType is used to customize logging. Note that we use a pointer to T so
diff --git a/pkg/sentry/vfs/vfs.go b/pkg/sentry/vfs/vfs.go
index 1ebf355ef..ed1cf99ba 100644
--- a/pkg/sentry/vfs/vfs.go
+++ b/pkg/sentry/vfs/vfs.go
@@ -819,30 +819,6 @@ func (vfs *VirtualFilesystem) MkdirAllAt(ctx context.Context, currentPath string
 	return nil
 }
 
-// MakeSyntheticMountpoint creates parent directories of target if they do not
-// exist and attempts to create a directory for the mountpoint. If a
-// non-directory file already exists there then we allow it.
-func (vfs *VirtualFilesystem) MakeSyntheticMountpoint(ctx context.Context, target string, root VirtualDentry, creds *auth.Credentials) error {
-	mkdirOpts := &MkdirOptions{Mode: 0777, ForSyntheticMountpoint: true}
-
-	// Make sure the parent directory of target exists.
-	if err := vfs.MkdirAllAt(ctx, path.Dir(target), root, creds, mkdirOpts); err != nil {
-		return fmt.Errorf("failed to create parent directory of mountpoint %q: %w", target, err)
-	}
-
-	// Attempt to mkdir the final component. If a file (of any type) exists
-	// then we let allow mounting on top of that because we do not require the
-	// target to be an existing directory, unlike Linux mount(2).
-	if err := vfs.MkdirAt(ctx, creds, &PathOperation{
-		Root:  root,
-		Start: root,
-		Path:  fspath.Parse(target),
-	}, mkdirOpts); err != nil && err != syserror.EEXIST {
-		return fmt.Errorf("failed to create mountpoint %q: %w", target, err)
-	}
-	return nil
-}
-
 // A VirtualDentry represents a node in a VFS tree, by combining a Dentry
 // (which represents a node in a Filesystem's tree) and a Mount (which
 // represents the Filesystem's position in a VFS mount tree).