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-rw-r--r--pkg/sentry/fsimpl/verity/filesystem.go18
-rw-r--r--pkg/sentry/fsimpl/verity/verity.go66
-rw-r--r--pkg/sentry/fsimpl/verity/verity_test.go407
-rw-r--r--pkg/sentry/vfs/vfs.go4
4 files changed, 470 insertions, 25 deletions
diff --git a/pkg/sentry/fsimpl/verity/filesystem.go b/pkg/sentry/fsimpl/verity/filesystem.go
index a4ad625bb..9057d2b4e 100644
--- a/pkg/sentry/fsimpl/verity/filesystem.go
+++ b/pkg/sentry/fsimpl/verity/filesystem.go
@@ -426,6 +426,17 @@ func (fs *filesystem) verifyStatAndChildrenLocked(ctx context.Context, d *dentry
params.DataAndTreeInSameFile = true
}
+ if d.isSymlink() {
+ target, err := vfsObj.ReadlinkAt(ctx, d.fs.creds, &vfs.PathOperation{
+ Root: d.lowerVD,
+ Start: d.lowerVD,
+ })
+ if err != nil {
+ return err
+ }
+ params.SymlinkTarget = target
+ }
+
if _, err := merkletree.Verify(params); err != nil && err != io.EOF {
return alertIntegrityViolation(fmt.Sprintf("Verification stat for %s failed: %v", childPath, err))
}
@@ -433,6 +444,7 @@ func (fs *filesystem) verifyStatAndChildrenLocked(ctx context.Context, d *dentry
d.uid = stat.UID
d.gid = stat.GID
d.size = uint32(size)
+ d.symlinkTarget = params.SymlinkTarget
return nil
}
@@ -934,11 +946,7 @@ func (fs *filesystem) ReadlinkAt(ctx context.Context, rp *vfs.ResolvingPath) (st
if err != nil {
return "", err
}
- //TODO(b/162787271): Provide integrity check for ReadlinkAt.
- return fs.vfsfs.VirtualFilesystem().ReadlinkAt(ctx, d.fs.creds, &vfs.PathOperation{
- Root: d.lowerVD,
- Start: d.lowerVD,
- })
+ return d.readlink(ctx)
}
// RenameAt implements vfs.FilesystemImpl.RenameAt.
diff --git a/pkg/sentry/fsimpl/verity/verity.go b/pkg/sentry/fsimpl/verity/verity.go
index 8645078a0..374f71568 100644
--- a/pkg/sentry/fsimpl/verity/verity.go
+++ b/pkg/sentry/fsimpl/verity/verity.go
@@ -332,6 +332,11 @@ func (fstype FilesystemType) GetFilesystem(ctx context.Context, vfsObj *vfs.Virt
d.hash = make([]byte, len(iopts.RootHash))
d.childrenNames = make(map[string]struct{})
+ if !d.isDir() {
+ ctx.Warningf("verity root must be a directory")
+ return nil, nil, syserror.EINVAL
+ }
+
if !fs.allowRuntimeEnable {
// Get children names from the underlying file system.
offString, err := vfsObj.GetXattrAt(ctx, creds, &vfs.PathOperation{
@@ -461,6 +466,9 @@ type dentry struct {
// initialized.
lowerMerkleVD vfs.VirtualDentry
+ // symlinkTarget is the target path of a symlink file in the underlying filesystem.
+ symlinkTarget string
+
// hash is the calculated hash for the current file or directory. hash
// is protected by hashMu.
hashMu sync.RWMutex `state:"nosave"`
@@ -645,6 +653,23 @@ func (d *dentry) getLowerAt(ctx context.Context, vfsObj *vfs.VirtualFilesystem,
}
func (d *dentry) readlink(ctx context.Context) (string, error) {
+ vfsObj := d.fs.vfsfs.VirtualFilesystem()
+ if d.verityEnabled() {
+ stat, err := vfsObj.StatAt(ctx, d.fs.creds, &vfs.PathOperation{
+ Root: d.lowerVD,
+ Start: d.lowerVD,
+ }, &vfs.StatOptions{})
+ if err != nil {
+ return "", err
+ }
+ d.dirMu.Lock()
+ defer d.dirMu.Unlock()
+ if err := d.fs.verifyStatAndChildrenLocked(ctx, d, stat); err != nil {
+ return "", err
+ }
+ return d.symlinkTarget, nil
+ }
+
return d.fs.vfsfs.VirtualFilesystem().ReadlinkAt(ctx, d.fs.creds, &vfs.PathOperation{
Root: d.lowerVD,
Start: d.lowerVD,
@@ -756,7 +781,8 @@ func (fd *fileDescription) Seek(ctx context.Context, offset int64, whence int32)
// hash of the generated Merkle tree and the data size is returned. If fd
// points to a regular file, the data is the content of the file. If fd points
// to a directory, the data is all hashes of its children, written to the Merkle
-// tree file.
+// tree file. If fd represents a symlink, the data is empty and nothing is written
+// to the Merkle tree file.
//
// Preconditions: fd.d.fs.verityMu must be locked.
func (fd *fileDescription) generateMerkleLocked(ctx context.Context) ([]byte, uint64, error) {
@@ -772,30 +798,30 @@ func (fd *fileDescription) generateMerkleLocked(ctx context.Context) ([]byte, ui
FD: fd.merkleWriter,
Ctx: ctx,
}
+
+ stat, err := fd.lowerFD.Stat(ctx, vfs.StatOptions{})
+ if err != nil {
+ return nil, 0, err
+ }
+
params := &merkletree.GenerateParams{
TreeReader: &merkleReader,
TreeWriter: &merkleWriter,
Children: fd.d.childrenNames,
//TODO(b/156980949): Support passing other hash algorithms.
HashAlgorithms: fd.d.fs.alg.toLinuxHashAlg(),
+ Name: fd.d.name,
+ Mode: uint32(stat.Mode),
+ UID: stat.UID,
+ GID: stat.GID,
}
switch atomic.LoadUint32(&fd.d.mode) & linux.S_IFMT {
case linux.S_IFREG:
// For a regular file, generate a Merkle tree based on its
// content.
- var err error
- stat, err := fd.lowerFD.Stat(ctx, vfs.StatOptions{})
- if err != nil {
- return nil, 0, err
- }
-
params.File = &fdReader
params.Size = int64(stat.Size)
- params.Name = fd.d.name
- params.Mode = uint32(stat.Mode)
- params.UID = stat.UID
- params.GID = stat.GID
params.DataAndTreeInSameFile = false
case linux.S_IFDIR:
// For a directory, generate a Merkle tree based on the hashes
@@ -807,18 +833,20 @@ func (fd *fileDescription) generateMerkleLocked(ctx context.Context) ([]byte, ui
}
params.Size = int64(merkleStat.Size)
-
- stat, err := fd.lowerFD.Stat(ctx, vfs.StatOptions{})
+ params.File = &merkleReader
+ params.DataAndTreeInSameFile = true
+ case linux.S_IFLNK:
+ // For a symlink, generate a Merkle tree file but do not write the root hash
+ // of the target file content to it. Return a hash of a VerityDescriptor object
+ // which includes the symlink target name.
+ target, err := fd.d.readlink(ctx)
if err != nil {
return nil, 0, err
}
- params.File = &merkleReader
- params.Name = fd.d.name
- params.Mode = uint32(stat.Mode)
- params.UID = stat.UID
- params.GID = stat.GID
- params.DataAndTreeInSameFile = true
+ params.Size = int64(stat.Size)
+ params.DataAndTreeInSameFile = false
+ params.SymlinkTarget = target
default:
// TODO(b/167728857): Investigate whether and how we should
// enable other types of file.
diff --git a/pkg/sentry/fsimpl/verity/verity_test.go b/pkg/sentry/fsimpl/verity/verity_test.go
index 798d6a9bd..57bd65202 100644
--- a/pkg/sentry/fsimpl/verity/verity_test.go
+++ b/pkg/sentry/fsimpl/verity/verity_test.go
@@ -163,6 +163,17 @@ func (d *dentry) openLowerMerkleAt(ctx context.Context, vfsObj *vfs.VirtualFiles
})
}
+// mkdirLowerAt creates a directory in the underlying file system.
+func (d *dentry) mkdirLowerAt(ctx context.Context, vfsObj *vfs.VirtualFilesystem, path string, mode linux.FileMode) error {
+ return vfsObj.MkdirAt(ctx, auth.CredentialsFromContext(ctx), &vfs.PathOperation{
+ Root: d.lowerVD,
+ Start: d.lowerVD,
+ Path: fspath.Parse(path),
+ }, &vfs.MkdirOptions{
+ Mode: mode,
+ })
+}
+
// unlinkLowerAt deletes the file in the underlying file system.
func (d *dentry) unlinkLowerAt(ctx context.Context, vfsObj *vfs.VirtualFilesystem, path string) error {
return vfsObj.UnlinkAt(ctx, auth.CredentialsFromContext(ctx), &vfs.PathOperation{
@@ -208,6 +219,16 @@ func (d *dentry) renameLowerMerkleAt(ctx context.Context, vfsObj *vfs.VirtualFil
}, &vfs.RenameOptions{})
}
+// symlinkLowerAt creates a symbolic link at symlink referring to the given target
+// in the underlying filesystem.
+func (d *dentry) symlinkLowerAt(ctx context.Context, vfsObj *vfs.VirtualFilesystem, target, symlink string) error {
+ return vfsObj.SymlinkAt(ctx, auth.CredentialsFromContext(ctx), &vfs.PathOperation{
+ Root: d.lowerVD,
+ Start: d.lowerVD,
+ Path: fspath.Parse(symlink),
+ }, target)
+}
+
// newFileFD creates a new file in the verity mount, and returns the FD. The FD
// points to a file that has random data generated.
func newFileFD(ctx context.Context, t *testing.T, vfsObj *vfs.VirtualFilesystem, root vfs.VirtualDentry, filePath string, mode linux.FileMode) (*vfs.FileDescription, int, error) {
@@ -239,6 +260,18 @@ func newFileFD(ctx context.Context, t *testing.T, vfsObj *vfs.VirtualFilesystem,
return fd, dataSize, err
}
+// newDirFD creates a new directory in the verity mount, and returns the FD.
+func newDirFD(ctx context.Context, t *testing.T, vfsObj *vfs.VirtualFilesystem, root vfs.VirtualDentry, dirPath string, mode linux.FileMode) (*vfs.FileDescription, error) {
+ // Create the directory in the underlying file system.
+ if err := dentryFromVD(t, root).mkdirLowerAt(ctx, vfsObj, dirPath, linux.ModeRegular|mode); err != nil {
+ return nil, err
+ }
+ if _, err := dentryFromVD(t, root).openLowerAt(ctx, vfsObj, dirPath, linux.O_RDONLY|linux.O_DIRECTORY, linux.ModeRegular|mode); err != nil {
+ return nil, err
+ }
+ return openVerityAt(ctx, vfsObj, root, dirPath, linux.O_RDONLY|linux.O_DIRECTORY, mode)
+}
+
// newEmptyFileFD creates a new empty file in the verity mount, and returns the FD.
func newEmptyFileFD(ctx context.Context, t *testing.T, vfsObj *vfs.VirtualFilesystem, root vfs.VirtualDentry, filePath string, mode linux.FileMode) (*vfs.FileDescription, error) {
// Create the file in the underlying file system.
@@ -801,3 +834,377 @@ func TestOpenRenamedFileFails(t *testing.T) {
})
}
}
+
+// TestUnmodifiedSymlinkFileReadSucceeds ensures that readlink() for an
+// unmodified verity enabled symlink succeeds.
+func TestUnmodifiedSymlinkFileReadSucceeds(t *testing.T) {
+ testCases := []struct {
+ name string
+ // The symlink target is a directory.
+ hasDirectoryTarget bool
+ // The symlink target is a directory and contains a regular file which will be
+ // used to test walking a symlink.
+ testWalk bool
+ }{
+ {
+ name: "RegularFileTarget",
+ hasDirectoryTarget: false,
+ testWalk: false,
+ },
+ {
+ name: "DirectoryTarget",
+ hasDirectoryTarget: true,
+ testWalk: false,
+ },
+ {
+ name: "RegularFileInSymlinkDirectory",
+ hasDirectoryTarget: true,
+ testWalk: true,
+ },
+ }
+ for _, tc := range testCases {
+ t.Run(tc.name, func(t *testing.T) {
+ if tc.testWalk && !tc.hasDirectoryTarget {
+ t.Fatalf("Invalid test case: hasDirectoryTarget can't be false when testing symlink walk")
+ }
+
+ vfsObj, root, ctx, err := newVerityRoot(t, SHA256)
+ if err != nil {
+ t.Fatalf("newVerityRoot: %v", err)
+ }
+
+ var target string
+ if tc.hasDirectoryTarget {
+ target = "verity-test-dir"
+ if _, err := newDirFD(ctx, t, vfsObj, root, target, 0644); err != nil {
+ t.Fatalf("newDirFD: %v", err)
+ }
+ } else {
+ target = "verity-test-file"
+ if _, _, err := newFileFD(ctx, t, vfsObj, root, target, 0644); err != nil {
+ t.Fatalf("newFileFD: %v", err)
+ }
+ }
+
+ if tc.testWalk {
+ fileInTargetDirectory := target + "/" + "verity-test-file"
+ if _, _, err := newFileFD(ctx, t, vfsObj, root, fileInTargetDirectory, 0644); err != nil {
+ t.Fatalf("newFileFD: %v", err)
+ }
+ }
+
+ symlink := "verity-test-symlink"
+ if err := dentryFromVD(t, root).symlinkLowerAt(ctx, vfsObj, target, symlink); err != nil {
+ t.Fatalf("SymlinkAt: %v", err)
+ }
+
+ fd, err := openVerityAt(ctx, vfsObj, root, symlink, linux.O_PATH|linux.O_NOFOLLOW, linux.ModeRegular)
+
+ if err != nil {
+ t.Fatalf("openVerityAt symlink: %v", err)
+ }
+
+ enableVerity(ctx, t, fd)
+
+ if _, err := vfsObj.ReadlinkAt(ctx, auth.CredentialsFromContext(ctx), &vfs.PathOperation{
+ Root: root,
+ Start: root,
+ Path: fspath.Parse(symlink),
+ }); err != nil {
+ t.Fatalf("ReadlinkAt: %v", err)
+ }
+
+ if tc.testWalk {
+ fileInSymlinkDirectory := symlink + "/verity-test-file"
+ // Ensure opening the verity enabled file in the symlink directory succeeds.
+ if _, err := openVerityAt(ctx, vfsObj, root, fileInSymlinkDirectory, linux.O_RDONLY, linux.ModeRegular); err != nil {
+ t.Errorf("open enabled file failed: %v", err)
+ }
+ }
+ })
+ }
+}
+
+// TestDeletedSymlinkFileReadFails ensures that reading value of a deleted verity enabled
+// symlink fails.
+func TestDeletedSymlinkFileReadFails(t *testing.T) {
+ testCases := []struct {
+ name string
+ // The original symlink is unlinked if deleteLink is true.
+ deleteLink bool
+ // The Merkle tree file is renamed if deleteMerkleFile is true.
+ deleteMerkleFile bool
+ // The symlink target is a directory.
+ hasDirectoryTarget bool
+ // The symlink target is a directory and contains a regular file which will be
+ // used to test walking a symlink.
+ testWalk bool
+ }{
+ {
+ name: "DeleteLinkRegularFile",
+ deleteLink: true,
+ deleteMerkleFile: false,
+ hasDirectoryTarget: false,
+ testWalk: false,
+ },
+ {
+ name: "DeleteMerkleRegFile",
+ deleteLink: false,
+ deleteMerkleFile: true,
+ hasDirectoryTarget: false,
+ testWalk: false,
+ },
+ {
+ name: "DeleteLinkAndMerkleRegFile",
+ deleteLink: true,
+ deleteMerkleFile: true,
+ hasDirectoryTarget: false,
+ testWalk: false,
+ },
+ {
+ name: "DeleteLinkDirectory",
+ deleteLink: true,
+ deleteMerkleFile: false,
+ hasDirectoryTarget: true,
+ testWalk: false,
+ },
+ {
+ name: "DeleteMerkleDirectory",
+ deleteLink: false,
+ deleteMerkleFile: true,
+ hasDirectoryTarget: true,
+ testWalk: false,
+ },
+ {
+ name: "DeleteLinkAndMerkleDirectory",
+ deleteLink: true,
+ deleteMerkleFile: true,
+ hasDirectoryTarget: true,
+ testWalk: false,
+ },
+ {
+ name: "DeleteLinkDirectoryWalk",
+ deleteLink: true,
+ deleteMerkleFile: false,
+ hasDirectoryTarget: true,
+ testWalk: true,
+ },
+ {
+ name: "DeleteMerkleDirectoryWalk",
+ deleteLink: false,
+ deleteMerkleFile: true,
+ hasDirectoryTarget: true,
+ testWalk: true,
+ },
+ {
+ name: "DeleteLinkAndMerkleDirectoryWalk",
+ deleteLink: true,
+ deleteMerkleFile: true,
+ hasDirectoryTarget: true,
+ testWalk: true,
+ },
+ }
+ for _, tc := range testCases {
+ t.Run(tc.name, func(t *testing.T) {
+ if tc.testWalk && !tc.hasDirectoryTarget {
+ t.Fatalf("Invalid test case: hasDirectoryTarget can't be false when testing symlink walk")
+ }
+
+ vfsObj, root, ctx, err := newVerityRoot(t, SHA256)
+ if err != nil {
+ t.Fatalf("newVerityRoot: %v", err)
+ }
+
+ var target string
+ if tc.hasDirectoryTarget {
+ target = "verity-test-dir"
+ if _, err := newDirFD(ctx, t, vfsObj, root, target, 0644); err != nil {
+ t.Fatalf("newDirFD: %v", err)
+ }
+ } else {
+ target = "verity-test-file"
+ if _, _, err := newFileFD(ctx, t, vfsObj, root, target, 0644); err != nil {
+ t.Fatalf("newFileFD: %v", err)
+ }
+ }
+
+ symlink := "verity-test-symlink"
+ if err := dentryFromVD(t, root).symlinkLowerAt(ctx, vfsObj, target, symlink); err != nil {
+ t.Fatalf("SymlinkAt: %v", err)
+ }
+
+ fd, err := openVerityAt(ctx, vfsObj, root, symlink, linux.O_PATH|linux.O_NOFOLLOW, linux.ModeRegular)
+
+ if err != nil {
+ t.Fatalf("openVerityAt symlink: %v", err)
+ }
+
+ if tc.testWalk {
+ fileInTargetDirectory := target + "/" + "verity-test-file"
+ if _, _, err := newFileFD(ctx, t, vfsObj, root, fileInTargetDirectory, 0644); err != nil {
+ t.Fatalf("newFileFD: %v", err)
+ }
+ }
+
+ enableVerity(ctx, t, fd)
+
+ if tc.deleteLink {
+ if err := dentryFromVD(t, root).unlinkLowerAt(ctx, vfsObj, symlink); err != nil {
+ t.Fatalf("UnlinkAt: %v", err)
+ }
+ }
+ if tc.deleteMerkleFile {
+ if err := dentryFromVD(t, root).unlinkLowerMerkleAt(ctx, vfsObj, symlink); err != nil {
+ t.Fatalf("UnlinkAt: %v", err)
+ }
+ }
+ if _, err := vfsObj.ReadlinkAt(ctx, auth.CredentialsFromContext(ctx), &vfs.PathOperation{
+ Root: root,
+ Start: root,
+ Path: fspath.Parse(symlink),
+ }); err != syserror.EIO {
+ t.Fatalf("ReadlinkAt succeeded with modified symlink: %v", err)
+ }
+
+ if tc.testWalk {
+ fileInSymlinkDirectory := symlink + "/verity-test-file"
+ // Ensure opening the verity enabled file in the symlink directory fails.
+ if _, err := openVerityAt(ctx, vfsObj, root, fileInSymlinkDirectory, linux.O_RDONLY, linux.ModeRegular); err != syserror.EIO {
+ t.Errorf("Open succeeded with modified symlink: %v", err)
+ }
+ }
+ })
+ }
+}
+
+// TestModifiedSymlinkFileReadFails ensures that reading value of a modified verity enabled
+// symlink fails.
+func TestModifiedSymlinkFileReadFails(t *testing.T) {
+ testCases := []struct {
+ name string
+ // The symlink target is a directory.
+ hasDirectoryTarget bool
+ // The symlink target is a directory and contains a regular file which will be
+ // used to test walking a symlink.
+ testWalk bool
+ }{
+ {
+ name: "RegularFileTarget",
+ hasDirectoryTarget: false,
+ testWalk: false,
+ },
+ {
+ name: "DirectoryTarget",
+ hasDirectoryTarget: true,
+ testWalk: false,
+ },
+ {
+ name: "RegularFileInSymlinkDirectory",
+ hasDirectoryTarget: true,
+ testWalk: true,
+ },
+ }
+ for _, tc := range testCases {
+ t.Run(tc.name, func(t *testing.T) {
+ if tc.testWalk && !tc.hasDirectoryTarget {
+ t.Fatalf("Invalid test case: hasDirectoryTarget can't be false when testing symlink walk")
+ }
+
+ vfsObj, root, ctx, err := newVerityRoot(t, SHA256)
+ if err != nil {
+ t.Fatalf("newVerityRoot: %v", err)
+ }
+
+ var target string
+ if tc.hasDirectoryTarget {
+ target = "verity-test-dir"
+ if _, err := newDirFD(ctx, t, vfsObj, root, target, 0644); err != nil {
+ t.Fatalf("newDirFD: %v", err)
+ }
+ } else {
+ target = "verity-test-file"
+ if _, _, err := newFileFD(ctx, t, vfsObj, root, target, 0644); err != nil {
+ t.Fatalf("newFileFD: %v", err)
+ }
+ }
+
+ // Create symlink which points to target file.
+ symlink := "verity-test-symlink"
+ if err := dentryFromVD(t, root).symlinkLowerAt(ctx, vfsObj, target, symlink); err != nil {
+ t.Fatalf("SymlinkAt: %v", err)
+ }
+
+ // Open symlink file to get the fd for ioctl in new step.
+ fd, err := openVerityAt(ctx, vfsObj, root, symlink, linux.O_PATH|linux.O_NOFOLLOW, linux.ModeRegular)
+ if err != nil {
+ t.Fatalf("OpenAt symlink: %v", err)
+ }
+
+ if tc.testWalk {
+ fileInTargetDirectory := target + "/" + "verity-test-file"
+ if _, _, err := newFileFD(ctx, t, vfsObj, root, fileInTargetDirectory, 0644); err != nil {
+ t.Fatalf("newFileFD: %v", err)
+ }
+ }
+
+ enableVerity(ctx, t, fd)
+
+ var newTarget string
+ if tc.hasDirectoryTarget {
+ newTarget = "verity-test-dir-new"
+ if _, err := newDirFD(ctx, t, vfsObj, root, newTarget, 0644); err != nil {
+ t.Fatalf("newDirFD: %v", err)
+ }
+ } else {
+ newTarget = "verity-test-file-new"
+ if _, _, err := newFileFD(ctx, t, vfsObj, root, newTarget, 0644); err != nil {
+ t.Fatalf("newFileFD: %v", err)
+ }
+ }
+
+ // Unlink symlink->target.
+ if err := dentryFromVD(t, root).unlinkLowerAt(ctx, vfsObj, symlink); err != nil {
+ t.Fatalf("UnlinkAt: %v", err)
+ }
+
+ // Link symlink->newTarget.
+ if err := dentryFromVD(t, root).symlinkLowerAt(ctx, vfsObj, newTarget, symlink); err != nil {
+ t.Fatalf("SymlinkAt: %v", err)
+ }
+
+ // Freshen lower dentry for symlink.
+ symlinkVD, err := vfsObj.GetDentryAt(ctx, auth.CredentialsFromContext(ctx), &vfs.PathOperation{
+ Root: root,
+ Start: root,
+ Path: fspath.Parse(symlink),
+ }, &vfs.GetDentryOptions{})
+ if err != nil {
+ t.Fatalf("Failed to get symlink dentry: %v", err)
+ }
+ symlinkDentry := dentryFromVD(t, symlinkVD)
+
+ symlinkLowerVD, err := dentryFromVD(t, root).getLowerAt(ctx, vfsObj, symlink)
+ if err != nil {
+ t.Fatalf("Failed to get symlink lower dentry: %v", err)
+ }
+ symlinkDentry.lowerVD = symlinkLowerVD
+
+ // Verify ReadlinkAt() fails.
+ if _, err := vfsObj.ReadlinkAt(ctx, auth.CredentialsFromContext(ctx), &vfs.PathOperation{
+ Root: root,
+ Start: root,
+ Path: fspath.Parse(symlink),
+ }); err != syserror.EIO {
+ t.Fatalf("ReadlinkAt succeeded with modified symlink: %v", err)
+ }
+
+ if tc.testWalk {
+ fileInSymlinkDirectory := symlink + "/verity-test-file"
+ // Ensure opening the verity enabled file in the symlink directory fails.
+ if _, err := openVerityAt(ctx, vfsObj, root, fileInSymlinkDirectory, linux.O_RDONLY, linux.ModeRegular); err != syserror.EIO {
+ t.Errorf("Open succeeded with modified symlink: %v", err)
+ }
+ }
+ })
+ }
+}
diff --git a/pkg/sentry/vfs/vfs.go b/pkg/sentry/vfs/vfs.go
index 0aff2dd92..b0e13cdab 100644
--- a/pkg/sentry/vfs/vfs.go
+++ b/pkg/sentry/vfs/vfs.go
@@ -425,7 +425,9 @@ func (vfs *VirtualFilesystem) OpenAt(ctx context.Context, creds *auth.Credential
rp.mustBeDir = true
rp.mustBeDirOrig = true
}
- if opts.Flags&linux.O_PATH != 0 {
+ // Ignore O_PATH for verity, as verity performs extra operations on the fd for verification.
+ // The underlying filesystem that verity wraps opens the fd with O_PATH.
+ if opts.Flags&linux.O_PATH != 0 && rp.mount.fs.FilesystemType().Name() != "verity" {
vd, err := vfs.GetDentryAt(ctx, creds, pop, &GetDentryOptions{})
if err != nil {
return nil, err
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-30 11:42:53 +0000