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-rw-r--r--pkg/sentry/fsimpl/verity/filesystem.go99
-rw-r--r--pkg/sentry/fsimpl/verity/verity.go34
2 files changed, 86 insertions, 47 deletions
diff --git a/pkg/sentry/fsimpl/verity/filesystem.go b/pkg/sentry/fsimpl/verity/filesystem.go
index 03da505e1..7e75c67c8 100644
--- a/pkg/sentry/fsimpl/verity/filesystem.go
+++ b/pkg/sentry/fsimpl/verity/filesystem.go
@@ -192,7 +192,7 @@ func (fs *filesystem) verifyChild(ctx context.Context, parent *dentry, child *de
// contains the expected xattrs. If the file or the xattr does not
// exist, it indicates unexpected modifications to the file system.
if err == syserror.ENOENT || err == syserror.ENODATA {
- return nil, alertIntegrityViolation(err, fmt.Sprintf("Failed to get xattr %s for %s: %v", merkleOffsetInParentXattr, childPath, err))
+ return nil, alertIntegrityViolation(fmt.Sprintf("Failed to get xattr %s for %s: %v", merkleOffsetInParentXattr, childPath, err))
}
if err != nil {
return nil, err
@@ -201,7 +201,7 @@ func (fs *filesystem) verifyChild(ctx context.Context, parent *dentry, child *de
// unexpected modifications to the file system.
offset, err := strconv.Atoi(off)
if err != nil {
- return nil, alertIntegrityViolation(err, fmt.Sprintf("Failed to convert xattr %s for %s to int: %v", merkleOffsetInParentXattr, childPath, err))
+ return nil, alertIntegrityViolation(fmt.Sprintf("Failed to convert xattr %s for %s to int: %v", merkleOffsetInParentXattr, childPath, err))
}
// Open parent Merkle tree file to read and verify child's hash.
@@ -215,7 +215,7 @@ func (fs *filesystem) verifyChild(ctx context.Context, parent *dentry, child *de
// The parent Merkle tree file should have been created. If it's
// missing, it indicates an unexpected modification to the file system.
if err == syserror.ENOENT {
- return nil, alertIntegrityViolation(err, fmt.Sprintf("Failed to open parent Merkle file for %s: %v", childPath, err))
+ return nil, alertIntegrityViolation(fmt.Sprintf("Failed to open parent Merkle file for %s: %v", childPath, err))
}
if err != nil {
return nil, err
@@ -233,7 +233,7 @@ func (fs *filesystem) verifyChild(ctx context.Context, parent *dentry, child *de
// contains the expected xattrs. If the file or the xattr does not
// exist, it indicates unexpected modifications to the file system.
if err == syserror.ENOENT || err == syserror.ENODATA {
- return nil, alertIntegrityViolation(err, fmt.Sprintf("Failed to get xattr %s for %s: %v", merkleSizeXattr, childPath, err))
+ return nil, alertIntegrityViolation(fmt.Sprintf("Failed to get xattr %s for %s: %v", merkleSizeXattr, childPath, err))
}
if err != nil {
return nil, err
@@ -243,7 +243,7 @@ func (fs *filesystem) verifyChild(ctx context.Context, parent *dentry, child *de
// unexpected modifications to the file system.
parentSize, err := strconv.Atoi(dataSize)
if err != nil {
- return nil, alertIntegrityViolation(syserror.EINVAL, fmt.Sprintf("Failed to convert xattr %s for %s to int: %v", merkleSizeXattr, childPath, err))
+ return nil, alertIntegrityViolation(fmt.Sprintf("Failed to convert xattr %s for %s to int: %v", merkleSizeXattr, childPath, err))
}
fdReader := vfs.FileReadWriteSeeker{
@@ -256,7 +256,7 @@ func (fs *filesystem) verifyChild(ctx context.Context, parent *dentry, child *de
Start: parent.lowerVD,
}, &vfs.StatOptions{})
if err == syserror.ENOENT {
- return nil, alertIntegrityViolation(err, fmt.Sprintf("Failed to get parent stat for %s: %v", childPath, err))
+ return nil, alertIntegrityViolation(fmt.Sprintf("Failed to get parent stat for %s: %v", childPath, err))
}
if err != nil {
return nil, err
@@ -280,7 +280,7 @@ func (fs *filesystem) verifyChild(ctx context.Context, parent *dentry, child *de
Expected: parent.hash,
DataAndTreeInSameFile: true,
}); err != nil && err != io.EOF {
- return nil, alertIntegrityViolation(syserror.EIO, fmt.Sprintf("Verification for %s failed: %v", childPath, err))
+ return nil, alertIntegrityViolation(fmt.Sprintf("Verification for %s failed: %v", childPath, err))
}
// Cache child hash when it's verified the first time.
@@ -312,7 +312,7 @@ func (fs *filesystem) verifyStat(ctx context.Context, d *dentry, stat linux.Stat
Flags: linux.O_RDONLY,
})
if err == syserror.ENOENT {
- return alertIntegrityViolation(err, fmt.Sprintf("Failed to open merkle file for %s: %v", childPath, err))
+ return alertIntegrityViolation(fmt.Sprintf("Failed to open merkle file for %s: %v", childPath, err))
}
if err != nil {
return err
@@ -324,7 +324,7 @@ func (fs *filesystem) verifyStat(ctx context.Context, d *dentry, stat linux.Stat
})
if err == syserror.ENODATA {
- return alertIntegrityViolation(err, fmt.Sprintf("Failed to get xattr %s for merkle file of %s: %v", merkleSizeXattr, childPath, err))
+ return alertIntegrityViolation(fmt.Sprintf("Failed to get xattr %s for merkle file of %s: %v", merkleSizeXattr, childPath, err))
}
if err != nil {
return err
@@ -332,7 +332,7 @@ func (fs *filesystem) verifyStat(ctx context.Context, d *dentry, stat linux.Stat
size, err := strconv.Atoi(merkleSize)
if err != nil {
- return alertIntegrityViolation(syserror.EINVAL, fmt.Sprintf("Failed to convert xattr %s for %s to int: %v", merkleSizeXattr, childPath, err))
+ return alertIntegrityViolation(fmt.Sprintf("Failed to convert xattr %s for %s to int: %v", merkleSizeXattr, childPath, err))
}
fdReader := vfs.FileReadWriteSeeker{
@@ -360,7 +360,7 @@ func (fs *filesystem) verifyStat(ctx context.Context, d *dentry, stat linux.Stat
}
if _, err := merkletree.Verify(params); err != nil && err != io.EOF {
- return alertIntegrityViolation(err, fmt.Sprintf("Verification stat for %s failed: %v", childPath, err))
+ return alertIntegrityViolation(fmt.Sprintf("Verification stat for %s failed: %v", childPath, err))
}
d.mode = uint32(stat.Mode)
d.uid = stat.UID
@@ -371,6 +371,45 @@ func (fs *filesystem) verifyStat(ctx context.Context, d *dentry, stat linux.Stat
// Preconditions: fs.renameMu must be locked. d.dirMu must be locked.
func (fs *filesystem) getChildLocked(ctx context.Context, parent *dentry, name string, ds **[]*dentry) (*dentry, error) {
if child, ok := parent.children[name]; ok {
+ // If verity is enabled on child, we should check again whether
+ // the file and the corresponding Merkle tree are as expected,
+ // in order to catch deletion/renaming after the last time it's
+ // accessed.
+ if child.verityEnabled() {
+ vfsObj := fs.vfsfs.VirtualFilesystem()
+ // Get the path to the child dentry. This is only used
+ // to provide path information in failure case.
+ path, err := vfsObj.PathnameWithDeleted(ctx, child.fs.rootDentry.lowerVD, child.lowerVD)
+ if err != nil {
+ return nil, err
+ }
+
+ childVD, err := parent.getLowerAt(ctx, vfsObj, name)
+ if err == syserror.ENOENT {
+ // The file was previously accessed. If the
+ // file does not exist now, it indicates an
+ // unexpected modification to the file system.
+ return nil, alertIntegrityViolation(fmt.Sprintf("Target file %s is expected but missing", path))
+ }
+ if err != nil {
+ return nil, err
+ }
+ defer childVD.DecRef(ctx)
+
+ childMerkleVD, err := parent.getLowerAt(ctx, vfsObj, merklePrefix+name)
+ // The Merkle tree file was previous accessed. If it
+ // does not exist now, it indicates an unexpected
+ // modification to the file system.
+ if err == syserror.ENOENT {
+ return nil, alertIntegrityViolation(fmt.Sprintf("Expected Merkle file for target %s but none found", path))
+ }
+ if err != nil {
+ return nil, err
+ }
+
+ defer childMerkleVD.DecRef(ctx)
+ }
+
// If enabling verification on files/directories is not allowed
// during runtime, all cached children are already verified. If
// runtime enable is allowed and the parent directory is
@@ -418,13 +457,7 @@ func (fs *filesystem) getChildLocked(ctx context.Context, parent *dentry, name s
func (fs *filesystem) lookupAndVerifyLocked(ctx context.Context, parent *dentry, name string) (*dentry, error) {
vfsObj := fs.vfsfs.VirtualFilesystem()
- childFilename := fspath.Parse(name)
- childVD, childErr := vfsObj.GetDentryAt(ctx, fs.creds, &vfs.PathOperation{
- Root: parent.lowerVD,
- Start: parent.lowerVD,
- Path: childFilename,
- }, &vfs.GetDentryOptions{})
-
+ childVD, childErr := parent.getLowerAt(ctx, vfsObj, name)
// We will handle ENOENT separately, as it may indicate unexpected
// modifications to the file system, and may cause a sentry panic.
if childErr != nil && childErr != syserror.ENOENT {
@@ -437,13 +470,7 @@ func (fs *filesystem) lookupAndVerifyLocked(ctx context.Context, parent *dentry,
defer childVD.DecRef(ctx)
}
- childMerkleFilename := merklePrefix + name
- childMerkleVD, childMerkleErr := vfsObj.GetDentryAt(ctx, fs.creds, &vfs.PathOperation{
- Root: parent.lowerVD,
- Start: parent.lowerVD,
- Path: fspath.Parse(childMerkleFilename),
- }, &vfs.GetDentryOptions{})
-
+ childMerkleVD, childMerkleErr := parent.getLowerAt(ctx, vfsObj, merklePrefix+name)
// We will handle ENOENT separately, as it may indicate unexpected
// modifications to the file system, and may cause a sentry panic.
if childMerkleErr != nil && childMerkleErr != syserror.ENOENT {
@@ -472,7 +499,7 @@ func (fs *filesystem) lookupAndVerifyLocked(ctx context.Context, parent *dentry,
// corresponding Merkle tree is found. This indicates an
// unexpected modification to the file system that
// removed/renamed the child.
- return nil, alertIntegrityViolation(childErr, fmt.Sprintf("Target file %s is expected but missing", parentPath+"/"+name))
+ return nil, alertIntegrityViolation(fmt.Sprintf("Target file %s is expected but missing", parentPath+"/"+name))
} else if childErr == nil && childMerkleErr == syserror.ENOENT {
// If in allowRuntimeEnable mode, and the Merkle tree file is
// not created yet, we create an empty Merkle tree file, so that
@@ -488,7 +515,7 @@ func (fs *filesystem) lookupAndVerifyLocked(ctx context.Context, parent *dentry,
childMerkleFD, err := vfsObj.OpenAt(ctx, fs.creds, &vfs.PathOperation{
Root: parent.lowerVD,
Start: parent.lowerVD,
- Path: fspath.Parse(childMerkleFilename),
+ Path: fspath.Parse(merklePrefix + name),
}, &vfs.OpenOptions{
Flags: linux.O_RDWR | linux.O_CREAT,
Mode: 0644,
@@ -497,11 +524,7 @@ func (fs *filesystem) lookupAndVerifyLocked(ctx context.Context, parent *dentry,
return nil, err
}
childMerkleFD.DecRef(ctx)
- childMerkleVD, err = vfsObj.GetDentryAt(ctx, fs.creds, &vfs.PathOperation{
- Root: parent.lowerVD,
- Start: parent.lowerVD,
- Path: fspath.Parse(childMerkleFilename),
- }, &vfs.GetDentryOptions{})
+ childMerkleVD, err = parent.getLowerAt(ctx, vfsObj, merklePrefix+name)
if err != nil {
return nil, err
}
@@ -509,7 +532,7 @@ func (fs *filesystem) lookupAndVerifyLocked(ctx context.Context, parent *dentry,
// If runtime enable is not allowed. This indicates an
// unexpected modification to the file system that
// removed/renamed the Merkle tree file.
- return nil, alertIntegrityViolation(childMerkleErr, fmt.Sprintf("Expected Merkle file for target %s but none found", parentPath+"/"+name))
+ return nil, alertIntegrityViolation(fmt.Sprintf("Expected Merkle file for target %s but none found", parentPath+"/"+name))
}
} else if childErr == syserror.ENOENT && childMerkleErr == syserror.ENOENT {
// Both the child and the corresponding Merkle tree are missing.
@@ -518,7 +541,7 @@ func (fs *filesystem) lookupAndVerifyLocked(ctx context.Context, parent *dentry,
// TODO(b/167752508): Investigate possible ways to differentiate
// cases that both files are deleted from cases that they never
// exist in the file system.
- return nil, alertIntegrityViolation(childErr, fmt.Sprintf("Failed to find file %s", parentPath+"/"+name))
+ return nil, alertIntegrityViolation(fmt.Sprintf("Failed to find file %s", parentPath+"/"+name))
}
mask := uint32(linux.STATX_TYPE | linux.STATX_MODE | linux.STATX_UID | linux.STATX_GID)
@@ -762,7 +785,7 @@ func (d *dentry) openLocked(ctx context.Context, rp *vfs.ResolvingPath, opts *vf
// missing, it indicates an unexpected modification to the file system.
if err != nil {
if err == syserror.ENOENT {
- return nil, alertIntegrityViolation(err, fmt.Sprintf("File %s expected but not found", path))
+ return nil, alertIntegrityViolation(fmt.Sprintf("File %s expected but not found", path))
}
return nil, err
}
@@ -785,7 +808,7 @@ func (d *dentry) openLocked(ctx context.Context, rp *vfs.ResolvingPath, opts *vf
// the file system.
if err != nil {
if err == syserror.ENOENT {
- return nil, alertIntegrityViolation(err, fmt.Sprintf("Merkle file for %s expected but not found", path))
+ return nil, alertIntegrityViolation(fmt.Sprintf("Merkle file for %s expected but not found", path))
}
return nil, err
}
@@ -810,7 +833,7 @@ func (d *dentry) openLocked(ctx context.Context, rp *vfs.ResolvingPath, opts *vf
})
if err != nil {
if err == syserror.ENOENT {
- return nil, alertIntegrityViolation(err, fmt.Sprintf("Merkle file for %s expected but not found", path))
+ return nil, alertIntegrityViolation(fmt.Sprintf("Merkle file for %s expected but not found", path))
}
return nil, err
}
@@ -828,7 +851,7 @@ func (d *dentry) openLocked(ctx context.Context, rp *vfs.ResolvingPath, opts *vf
if err != nil {
if err == syserror.ENOENT {
parentPath, _ := d.fs.vfsfs.VirtualFilesystem().PathnameWithDeleted(ctx, d.fs.rootDentry.lowerVD, d.parent.lowerVD)
- return nil, alertIntegrityViolation(err, fmt.Sprintf("Merkle file for %s expected but not found", parentPath))
+ return nil, alertIntegrityViolation(fmt.Sprintf("Merkle file for %s expected but not found", parentPath))
}
return nil, err
}
diff --git a/pkg/sentry/fsimpl/verity/verity.go b/pkg/sentry/fsimpl/verity/verity.go
index 8dc9e26bc..acc565a10 100644
--- a/pkg/sentry/fsimpl/verity/verity.go
+++ b/pkg/sentry/fsimpl/verity/verity.go
@@ -153,10 +153,10 @@ func (FilesystemType) Release(ctx context.Context) {}
// alertIntegrityViolation alerts a violation of integrity, which usually means
// unexpected modification to the file system is detected. In
-// noCrashOnVerificationFailure mode, it returns an error, otherwise it panic.
-func alertIntegrityViolation(err error, msg string) error {
+// noCrashOnVerificationFailure mode, it returns EIO, otherwise it panic.
+func alertIntegrityViolation(msg string) error {
if noCrashOnVerificationFailure {
- return err
+ return syserror.EIO
}
panic(msg)
}
@@ -236,7 +236,7 @@ func (fstype FilesystemType) GetFilesystem(ctx context.Context, vfsObj *vfs.Virt
// the root Merkle file, or it's never generated.
fs.vfsfs.DecRef(ctx)
d.DecRef(ctx)
- return nil, nil, alertIntegrityViolation(err, "Failed to find root Merkle file")
+ return nil, nil, alertIntegrityViolation("Failed to find root Merkle file")
}
d.lowerMerkleVD = lowerMerkleVD
@@ -448,6 +448,16 @@ func (d *dentry) verityEnabled() bool {
return !d.fs.allowRuntimeEnable || len(d.hash) != 0
}
+// getLowerAt returns the dentry in the underlying file system, which is
+// represented by filename relative to d.
+func (d *dentry) getLowerAt(ctx context.Context, vfsObj *vfs.VirtualFilesystem, filename string) (vfs.VirtualDentry, error) {
+ return vfsObj.GetDentryAt(ctx, d.fs.creds, &vfs.PathOperation{
+ Root: d.lowerVD,
+ Start: d.lowerVD,
+ Path: fspath.Parse(filename),
+ }, &vfs.GetDentryOptions{})
+}
+
func (d *dentry) readlink(ctx context.Context) (string, error) {
return d.fs.vfsfs.VirtualFilesystem().ReadlinkAt(ctx, d.fs.creds, &vfs.PathOperation{
Root: d.lowerVD,
@@ -611,7 +621,7 @@ func (fd *fileDescription) enableVerity(ctx context.Context, uio usermem.IO) (ui
// or directory other than the root, the parent Merkle tree file should
// have also been initialized.
if fd.lowerFD == nil || fd.merkleReader == nil || fd.merkleWriter == nil || (fd.parentMerkleWriter == nil && fd.d != fd.d.fs.rootDentry) {
- return 0, alertIntegrityViolation(syserror.EIO, "Unexpected verity fd: missing expected underlying fds")
+ return 0, alertIntegrityViolation("Unexpected verity fd: missing expected underlying fds")
}
hash, dataSize, err := fd.generateMerkle(ctx)
@@ -657,6 +667,9 @@ func (fd *fileDescription) enableVerity(ctx context.Context, uio usermem.IO) (ui
// measureVerity returns the hash of fd, saved in verityDigest.
func (fd *fileDescription) measureVerity(ctx context.Context, uio usermem.IO, verityDigest usermem.Addr) (uintptr, error) {
t := kernel.TaskFromContext(ctx)
+ if t == nil {
+ return 0, syserror.EINVAL
+ }
var metadata linux.DigestMetadata
// If allowRuntimeEnable is true, an empty fd.d.hash indicates that
@@ -667,7 +680,7 @@ func (fd *fileDescription) measureVerity(ctx context.Context, uio usermem.IO, ve
if fd.d.fs.allowRuntimeEnable {
return 0, syserror.ENODATA
}
- return 0, alertIntegrityViolation(syserror.ENODATA, "Ioctl measureVerity: no hash found")
+ return 0, alertIntegrityViolation("Ioctl measureVerity: no hash found")
}
// The first part of VerityDigest is the metadata.
@@ -702,6 +715,9 @@ func (fd *fileDescription) verityFlags(ctx context.Context, uio usermem.IO, flag
}
t := kernel.TaskFromContext(ctx)
+ if t == nil {
+ return 0, syserror.EINVAL
+ }
_, err := primitive.CopyInt32Out(t, flags, f)
return 0, err
}
@@ -742,7 +758,7 @@ func (fd *fileDescription) PRead(ctx context.Context, dst usermem.IOSequence, of
// contains the expected xattrs. If the xattr does not exist, it
// indicates unexpected modifications to the file system.
if err == syserror.ENODATA {
- return 0, alertIntegrityViolation(err, fmt.Sprintf("Failed to get xattr %s: %v", merkleSizeXattr, err))
+ return 0, alertIntegrityViolation(fmt.Sprintf("Failed to get xattr %s: %v", merkleSizeXattr, err))
}
if err != nil {
return 0, err
@@ -752,7 +768,7 @@ func (fd *fileDescription) PRead(ctx context.Context, dst usermem.IOSequence, of
// unexpected modifications to the file system.
size, err := strconv.Atoi(dataSize)
if err != nil {
- return 0, alertIntegrityViolation(err, fmt.Sprintf("Failed to convert xattr %s to int: %v", merkleSizeXattr, err))
+ return 0, alertIntegrityViolation(fmt.Sprintf("Failed to convert xattr %s to int: %v", merkleSizeXattr, err))
}
dataReader := vfs.FileReadWriteSeeker{
@@ -780,7 +796,7 @@ func (fd *fileDescription) PRead(ctx context.Context, dst usermem.IOSequence, of
DataAndTreeInSameFile: false,
})
if err != nil {
- return 0, alertIntegrityViolation(syserror.EIO, fmt.Sprintf("Verification failed: %v", err))
+ return 0, alertIntegrityViolation(fmt.Sprintf("Verification failed: %v", err))
}
return n, err
}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-16 03:49:17 +0000