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-rw-r--r--pkg/sentry/vfs/anonfs.go4
-rw-r--r--pkg/sentry/vfs/file_description.go32
-rw-r--r--pkg/sentry/vfs/file_description_impl_util.go4
-rw-r--r--pkg/sentry/vfs/filesystem.go24
-rw-r--r--pkg/sentry/vfs/memxattr/BUILD15
-rw-r--r--pkg/sentry/vfs/memxattr/xattr.go102
-rw-r--r--pkg/sentry/vfs/options.go14
-rw-r--r--pkg/sentry/vfs/vfs.go8
8 files changed, 182 insertions, 21 deletions
diff --git a/pkg/sentry/vfs/anonfs.go b/pkg/sentry/vfs/anonfs.go
index d1f6dfb45..a64d86122 100644
--- a/pkg/sentry/vfs/anonfs.go
+++ b/pkg/sentry/vfs/anonfs.go
@@ -245,7 +245,7 @@ func (fs *anonFilesystem) BoundEndpointAt(ctx context.Context, rp *ResolvingPath
}
// ListxattrAt implements FilesystemImpl.ListxattrAt.
-func (fs *anonFilesystem) ListxattrAt(ctx context.Context, rp *ResolvingPath) ([]string, error) {
+func (fs *anonFilesystem) ListxattrAt(ctx context.Context, rp *ResolvingPath, size uint64) ([]string, error) {
if !rp.Done() {
return nil, syserror.ENOTDIR
}
@@ -253,7 +253,7 @@ func (fs *anonFilesystem) ListxattrAt(ctx context.Context, rp *ResolvingPath) ([
}
// GetxattrAt implements FilesystemImpl.GetxattrAt.
-func (fs *anonFilesystem) GetxattrAt(ctx context.Context, rp *ResolvingPath, name string) (string, error) {
+func (fs *anonFilesystem) GetxattrAt(ctx context.Context, rp *ResolvingPath, opts GetxattrOptions) (string, error) {
if !rp.Done() {
return "", syserror.ENOTDIR
}
diff --git a/pkg/sentry/vfs/file_description.go b/pkg/sentry/vfs/file_description.go
index 20c545fca..4fb9aea87 100644
--- a/pkg/sentry/vfs/file_description.go
+++ b/pkg/sentry/vfs/file_description.go
@@ -401,11 +401,11 @@ type FileDescriptionImpl interface {
Ioctl(ctx context.Context, uio usermem.IO, args arch.SyscallArguments) (uintptr, error)
// Listxattr returns all extended attribute names for the file.
- Listxattr(ctx context.Context) ([]string, error)
+ Listxattr(ctx context.Context, size uint64) ([]string, error)
// Getxattr returns the value associated with the given extended attribute
// for the file.
- Getxattr(ctx context.Context, name string) (string, error)
+ Getxattr(ctx context.Context, opts GetxattrOptions) (string, error)
// Setxattr changes the value associated with the given extended attribute
// for the file.
@@ -605,18 +605,23 @@ func (fd *FileDescription) Ioctl(ctx context.Context, uio usermem.IO, args arch.
// Listxattr returns all extended attribute names for the file represented by
// fd.
-func (fd *FileDescription) Listxattr(ctx context.Context) ([]string, error) {
+//
+// If the size of the list (including a NUL terminating byte after every entry)
+// would exceed size, ERANGE may be returned. Note that implementations
+// are free to ignore size entirely and return without error). In all cases,
+// if size is 0, the list should be returned without error, regardless of size.
+func (fd *FileDescription) Listxattr(ctx context.Context, size uint64) ([]string, error) {
if fd.opts.UseDentryMetadata {
vfsObj := fd.vd.mount.vfs
rp := vfsObj.getResolvingPath(auth.CredentialsFromContext(ctx), &PathOperation{
Root: fd.vd,
Start: fd.vd,
})
- names, err := fd.vd.mount.fs.impl.ListxattrAt(ctx, rp)
+ names, err := fd.vd.mount.fs.impl.ListxattrAt(ctx, rp, size)
vfsObj.putResolvingPath(rp)
return names, err
}
- names, err := fd.impl.Listxattr(ctx)
+ names, err := fd.impl.Listxattr(ctx, size)
if err == syserror.ENOTSUP {
// Linux doesn't actually return ENOTSUP in this case; instead,
// fs/xattr.c:vfs_listxattr() falls back to allowing the security
@@ -629,34 +634,39 @@ func (fd *FileDescription) Listxattr(ctx context.Context) ([]string, error) {
// Getxattr returns the value associated with the given extended attribute for
// the file represented by fd.
-func (fd *FileDescription) Getxattr(ctx context.Context, name string) (string, error) {
+//
+// If the size of the return value exceeds opts.Size, ERANGE may be returned
+// (note that implementations are free to ignore opts.Size entirely and return
+// without error). In all cases, if opts.Size is 0, the value should be
+// returned without error, regardless of size.
+func (fd *FileDescription) Getxattr(ctx context.Context, opts *GetxattrOptions) (string, error) {
if fd.opts.UseDentryMetadata {
vfsObj := fd.vd.mount.vfs
rp := vfsObj.getResolvingPath(auth.CredentialsFromContext(ctx), &PathOperation{
Root: fd.vd,
Start: fd.vd,
})
- val, err := fd.vd.mount.fs.impl.GetxattrAt(ctx, rp, name)
+ val, err := fd.vd.mount.fs.impl.GetxattrAt(ctx, rp, *opts)
vfsObj.putResolvingPath(rp)
return val, err
}
- return fd.impl.Getxattr(ctx, name)
+ return fd.impl.Getxattr(ctx, *opts)
}
// Setxattr changes the value associated with the given extended attribute for
// the file represented by fd.
-func (fd *FileDescription) Setxattr(ctx context.Context, opts SetxattrOptions) error {
+func (fd *FileDescription) Setxattr(ctx context.Context, opts *SetxattrOptions) error {
if fd.opts.UseDentryMetadata {
vfsObj := fd.vd.mount.vfs
rp := vfsObj.getResolvingPath(auth.CredentialsFromContext(ctx), &PathOperation{
Root: fd.vd,
Start: fd.vd,
})
- err := fd.vd.mount.fs.impl.SetxattrAt(ctx, rp, opts)
+ err := fd.vd.mount.fs.impl.SetxattrAt(ctx, rp, *opts)
vfsObj.putResolvingPath(rp)
return err
}
- return fd.impl.Setxattr(ctx, opts)
+ return fd.impl.Setxattr(ctx, *opts)
}
// Removexattr removes the given extended attribute from the file represented
diff --git a/pkg/sentry/vfs/file_description_impl_util.go b/pkg/sentry/vfs/file_description_impl_util.go
index d45e602ce..f4c111926 100644
--- a/pkg/sentry/vfs/file_description_impl_util.go
+++ b/pkg/sentry/vfs/file_description_impl_util.go
@@ -130,14 +130,14 @@ func (FileDescriptionDefaultImpl) Ioctl(ctx context.Context, uio usermem.IO, arg
// Listxattr implements FileDescriptionImpl.Listxattr analogously to
// inode_operations::listxattr == NULL in Linux.
-func (FileDescriptionDefaultImpl) Listxattr(ctx context.Context) ([]string, error) {
+func (FileDescriptionDefaultImpl) Listxattr(ctx context.Context, size uint64) ([]string, error) {
// This isn't exactly accurate; see FileDescription.Listxattr.
return nil, syserror.ENOTSUP
}
// Getxattr implements FileDescriptionImpl.Getxattr analogously to
// inode::i_opflags & IOP_XATTR == 0 in Linux.
-func (FileDescriptionDefaultImpl) Getxattr(ctx context.Context, name string) (string, error) {
+func (FileDescriptionDefaultImpl) Getxattr(ctx context.Context, opts GetxattrOptions) (string, error) {
return "", syserror.ENOTSUP
}
diff --git a/pkg/sentry/vfs/filesystem.go b/pkg/sentry/vfs/filesystem.go
index bef1bd312..a537a29d1 100644
--- a/pkg/sentry/vfs/filesystem.go
+++ b/pkg/sentry/vfs/filesystem.go
@@ -442,7 +442,13 @@ type FilesystemImpl interface {
// - If extended attributes are not supported by the filesystem,
// ListxattrAt returns nil. (See FileDescription.Listxattr for an
// explanation.)
- ListxattrAt(ctx context.Context, rp *ResolvingPath) ([]string, error)
+ //
+ // - If the size of the list (including a NUL terminating byte after every
+ // entry) would exceed size, ERANGE may be returned. Note that
+ // implementations are free to ignore size entirely and return without
+ // error). In all cases, if size is 0, the list should be returned without
+ // error, regardless of size.
+ ListxattrAt(ctx context.Context, rp *ResolvingPath, size uint64) ([]string, error)
// GetxattrAt returns the value associated with the given extended
// attribute for the file at rp.
@@ -451,7 +457,15 @@ type FilesystemImpl interface {
//
// - If extended attributes are not supported by the filesystem, GetxattrAt
// returns ENOTSUP.
- GetxattrAt(ctx context.Context, rp *ResolvingPath, name string) (string, error)
+ //
+ // - If an extended attribute named opts.Name does not exist, ENODATA is
+ // returned.
+ //
+ // - If the size of the return value exceeds opts.Size, ERANGE may be
+ // returned (note that implementations are free to ignore opts.Size entirely
+ // and return without error). In all cases, if opts.Size is 0, the value
+ // should be returned without error, regardless of size.
+ GetxattrAt(ctx context.Context, rp *ResolvingPath, opts GetxattrOptions) (string, error)
// SetxattrAt changes the value associated with the given extended
// attribute for the file at rp.
@@ -460,6 +474,10 @@ type FilesystemImpl interface {
//
// - If extended attributes are not supported by the filesystem, SetxattrAt
// returns ENOTSUP.
+ //
+ // - If XATTR_CREATE is set in opts.Flag and opts.Name already exists,
+ // EEXIST is returned. If XATTR_REPLACE is set and opts.Name does not exist,
+ // ENODATA is returned.
SetxattrAt(ctx context.Context, rp *ResolvingPath, opts SetxattrOptions) error
// RemovexattrAt removes the given extended attribute from the file at rp.
@@ -468,6 +486,8 @@ type FilesystemImpl interface {
//
// - If extended attributes are not supported by the filesystem,
// RemovexattrAt returns ENOTSUP.
+ //
+ // - If name does not exist, ENODATA is returned.
RemovexattrAt(ctx context.Context, rp *ResolvingPath, name string) error
// BoundEndpointAt returns the Unix socket endpoint bound at the path rp.
diff --git a/pkg/sentry/vfs/memxattr/BUILD b/pkg/sentry/vfs/memxattr/BUILD
new file mode 100644
index 000000000..d8c4d27b9
--- /dev/null
+++ b/pkg/sentry/vfs/memxattr/BUILD
@@ -0,0 +1,15 @@
+load("//tools:defs.bzl", "go_library")
+
+package(licenses = ["notice"])
+
+go_library(
+ name = "memxattr",
+ srcs = ["xattr.go"],
+ visibility = ["//pkg/sentry:internal"],
+ deps = [
+ "//pkg/abi/linux",
+ "//pkg/sentry/vfs",
+ "//pkg/sync",
+ "//pkg/syserror",
+ ],
+)
diff --git a/pkg/sentry/vfs/memxattr/xattr.go b/pkg/sentry/vfs/memxattr/xattr.go
new file mode 100644
index 000000000..cc1e7d764
--- /dev/null
+++ b/pkg/sentry/vfs/memxattr/xattr.go
@@ -0,0 +1,102 @@
+// Copyright 2020 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package memxattr provides a default, in-memory extended attribute
+// implementation.
+package memxattr
+
+import (
+ "gvisor.dev/gvisor/pkg/abi/linux"
+ "gvisor.dev/gvisor/pkg/sentry/vfs"
+ "gvisor.dev/gvisor/pkg/sync"
+ "gvisor.dev/gvisor/pkg/syserror"
+)
+
+// SimpleExtendedAttributes implements extended attributes using a map of
+// names to values.
+//
+// +stateify savable
+type SimpleExtendedAttributes struct {
+ // mu protects the below fields.
+ mu sync.RWMutex `state:"nosave"`
+ xattrs map[string]string
+}
+
+// Getxattr returns the value at 'name'.
+func (x *SimpleExtendedAttributes) Getxattr(opts *vfs.GetxattrOptions) (string, error) {
+ x.mu.RLock()
+ value, ok := x.xattrs[opts.Name]
+ x.mu.RUnlock()
+ if !ok {
+ return "", syserror.ENODATA
+ }
+ // Check that the size of the buffer provided in getxattr(2) is large enough
+ // to contain the value.
+ if opts.Size != 0 && uint64(len(value)) > opts.Size {
+ return "", syserror.ERANGE
+ }
+ return value, nil
+}
+
+// Setxattr sets 'value' at 'name'.
+func (x *SimpleExtendedAttributes) Setxattr(opts *vfs.SetxattrOptions) error {
+ x.mu.Lock()
+ defer x.mu.Unlock()
+ if x.xattrs == nil {
+ if opts.Flags&linux.XATTR_REPLACE != 0 {
+ return syserror.ENODATA
+ }
+ x.xattrs = make(map[string]string)
+ }
+
+ _, ok := x.xattrs[opts.Name]
+ if ok && opts.Flags&linux.XATTR_CREATE != 0 {
+ return syserror.EEXIST
+ }
+ if !ok && opts.Flags&linux.XATTR_REPLACE != 0 {
+ return syserror.ENODATA
+ }
+
+ x.xattrs[opts.Name] = opts.Value
+ return nil
+}
+
+// Listxattr returns all names in xattrs.
+func (x *SimpleExtendedAttributes) Listxattr(size uint64) ([]string, error) {
+ // Keep track of the size of the buffer needed in listxattr(2) for the list.
+ listSize := 0
+ x.mu.RLock()
+ names := make([]string, 0, len(x.xattrs))
+ for n := range x.xattrs {
+ names = append(names, n)
+ // Add one byte per null terminator.
+ listSize += len(n) + 1
+ }
+ x.mu.RUnlock()
+ if size != 0 && uint64(listSize) > size {
+ return nil, syserror.ERANGE
+ }
+ return names, nil
+}
+
+// Removexattr removes the xattr at 'name'.
+func (x *SimpleExtendedAttributes) Removexattr(name string) error {
+ x.mu.Lock()
+ defer x.mu.Unlock()
+ if _, ok := x.xattrs[name]; !ok {
+ return syserror.ENODATA
+ }
+ delete(x.xattrs, name)
+ return nil
+}
diff --git a/pkg/sentry/vfs/options.go b/pkg/sentry/vfs/options.go
index 2f04bf882..534528ce6 100644
--- a/pkg/sentry/vfs/options.go
+++ b/pkg/sentry/vfs/options.go
@@ -132,6 +132,20 @@ type SetStatOptions struct {
Stat linux.Statx
}
+// GetxattrOptions contains options to VirtualFilesystem.GetxattrAt(),
+// FilesystemImpl.GetxattrAt(), FileDescription.Getxattr(), and
+// FileDescriptionImpl.Getxattr().
+type GetxattrOptions struct {
+ // Name is the name of the extended attribute to retrieve.
+ Name string
+
+ // Size is the maximum value size that the caller will tolerate. If the value
+ // is larger than size, getxattr methods may return ERANGE, but they are also
+ // free to ignore the hint entirely (i.e. the value returned may be larger
+ // than size). All size checking is done independently at the syscall layer.
+ Size uint64
+}
+
// SetxattrOptions contains options to VirtualFilesystem.SetxattrAt(),
// FilesystemImpl.SetxattrAt(), FileDescription.Setxattr(), and
// FileDescriptionImpl.Setxattr().
diff --git a/pkg/sentry/vfs/vfs.go b/pkg/sentry/vfs/vfs.go
index 720b90d8f..f592913d5 100644
--- a/pkg/sentry/vfs/vfs.go
+++ b/pkg/sentry/vfs/vfs.go
@@ -680,10 +680,10 @@ func (vfs *VirtualFilesystem) UnlinkAt(ctx context.Context, creds *auth.Credenti
// ListxattrAt returns all extended attribute names for the file at the given
// path.
-func (vfs *VirtualFilesystem) ListxattrAt(ctx context.Context, creds *auth.Credentials, pop *PathOperation) ([]string, error) {
+func (vfs *VirtualFilesystem) ListxattrAt(ctx context.Context, creds *auth.Credentials, pop *PathOperation, size uint64) ([]string, error) {
rp := vfs.getResolvingPath(creds, pop)
for {
- names, err := rp.mount.fs.impl.ListxattrAt(ctx, rp)
+ names, err := rp.mount.fs.impl.ListxattrAt(ctx, rp, size)
if err == nil {
vfs.putResolvingPath(rp)
return names, nil
@@ -705,10 +705,10 @@ func (vfs *VirtualFilesystem) ListxattrAt(ctx context.Context, creds *auth.Crede
// GetxattrAt returns the value associated with the given extended attribute
// for the file at the given path.
-func (vfs *VirtualFilesystem) GetxattrAt(ctx context.Context, creds *auth.Credentials, pop *PathOperation, name string) (string, error) {
+func (vfs *VirtualFilesystem) GetxattrAt(ctx context.Context, creds *auth.Credentials, pop *PathOperation, opts *GetxattrOptions) (string, error) {
rp := vfs.getResolvingPath(creds, pop)
for {
- val, err := rp.mount.fs.impl.GetxattrAt(ctx, rp, name)
+ val, err := rp.mount.fs.impl.GetxattrAt(ctx, rp, *opts)
if err == nil {
vfs.putResolvingPath(rp)
return val, nil
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-06 12:28:43 +0000