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-rwxr-xr-xpkg/abi/linux/xattr.go27
-rw-r--r--pkg/sentry/fs/inode.go8
-rw-r--r--pkg/sentry/fs/inode_overlay.go5
-rwxr-xr-xpkg/sentry/syscalls/linux/linux64_amd64.go4
-rwxr-xr-xpkg/sentry/syscalls/linux/linux64_arm64.go4
-rwxr-xr-xpkg/sentry/syscalls/linux/sys_xattr.go169
6 files changed, 213 insertions, 4 deletions
diff --git a/pkg/abi/linux/xattr.go b/pkg/abi/linux/xattr.go
new file mode 100755
index 000000000..a3b6406fa
--- /dev/null
+++ b/pkg/abi/linux/xattr.go
@@ -0,0 +1,27 @@
+// Copyright 2019 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 linux
+
+// Constants for extended attributes.
+const (
+ XATTR_NAME_MAX = 255
+ XATTR_SIZE_MAX = 65536
+
+ XATTR_CREATE = 1
+ XATTR_REPLACE = 2
+
+ XATTR_USER_PREFIX = "user."
+ XATTR_USER_PREFIX_LEN = len(XATTR_USER_PREFIX)
+)
diff --git a/pkg/sentry/fs/inode.go b/pkg/sentry/fs/inode.go
index 2d43dff1d..91e2fde2f 100644
--- a/pkg/sentry/fs/inode.go
+++ b/pkg/sentry/fs/inode.go
@@ -270,6 +270,14 @@ func (i *Inode) Getxattr(name string) (string, error) {
return i.InodeOperations.Getxattr(i, name)
}
+// Setxattr calls i.InodeOperations.Setxattr with i as the Inode.
+func (i *Inode) Setxattr(name, value string) error {
+ if i.overlay != nil {
+ return overlaySetxattr(i.overlay, name, value)
+ }
+ return i.InodeOperations.Setxattr(i, name, value)
+}
+
// Listxattr calls i.InodeOperations.Listxattr with i as the Inode.
func (i *Inode) Listxattr() (map[string]struct{}, error) {
if i.overlay != nil {
diff --git a/pkg/sentry/fs/inode_overlay.go b/pkg/sentry/fs/inode_overlay.go
index a09147080..63a991beb 100644
--- a/pkg/sentry/fs/inode_overlay.go
+++ b/pkg/sentry/fs/inode_overlay.go
@@ -552,6 +552,11 @@ func overlayGetxattr(o *overlayEntry, name string) (string, error) {
return s, err
}
+// TODO(b/146028302): Support setxattr for overlayfs.
+func overlaySetxattr(o *overlayEntry, name, value string) error {
+ return syserror.EOPNOTSUPP
+}
+
func overlayListxattr(o *overlayEntry) (map[string]struct{}, error) {
o.copyMu.RLock()
defer o.copyMu.RUnlock()
diff --git a/pkg/sentry/syscalls/linux/linux64_amd64.go b/pkg/sentry/syscalls/linux/linux64_amd64.go
index 797542d28..272ae9991 100755
--- a/pkg/sentry/syscalls/linux/linux64_amd64.go
+++ b/pkg/sentry/syscalls/linux/linux64_amd64.go
@@ -228,10 +228,10 @@ var AMD64 = &kernel.SyscallTable{
185: syscalls.Error("security", syserror.ENOSYS, "Not implemented in Linux.", nil),
186: syscalls.Supported("gettid", Gettid),
187: syscalls.Supported("readahead", Readahead),
- 188: syscalls.Error("setxattr", syserror.ENOTSUP, "Requires filesystem support.", nil),
+ 188: syscalls.PartiallySupported("setxattr", Setxattr, "Only supported for tmpfs.", nil),
189: syscalls.Error("lsetxattr", syserror.ENOTSUP, "Requires filesystem support.", nil),
190: syscalls.Error("fsetxattr", syserror.ENOTSUP, "Requires filesystem support.", nil),
- 191: syscalls.ErrorWithEvent("getxattr", syserror.ENOTSUP, "Requires filesystem support.", nil),
+ 191: syscalls.PartiallySupported("getxattr", Getxattr, "Only supported for tmpfs.", nil),
192: syscalls.ErrorWithEvent("lgetxattr", syserror.ENOTSUP, "Requires filesystem support.", nil),
193: syscalls.ErrorWithEvent("fgetxattr", syserror.ENOTSUP, "Requires filesystem support.", nil),
194: syscalls.ErrorWithEvent("listxattr", syserror.ENOTSUP, "Requires filesystem support.", nil),
diff --git a/pkg/sentry/syscalls/linux/linux64_arm64.go b/pkg/sentry/syscalls/linux/linux64_arm64.go
index 2bc7faff5..3b584eed9 100755
--- a/pkg/sentry/syscalls/linux/linux64_arm64.go
+++ b/pkg/sentry/syscalls/linux/linux64_arm64.go
@@ -41,10 +41,10 @@ var ARM64 = &kernel.SyscallTable{
2: syscalls.PartiallySupported("io_submit", IoSubmit, "Generally supported with exceptions. User ring optimizations are not implemented.", []string{"gvisor.dev/issue/204"}),
3: syscalls.PartiallySupported("io_cancel", IoCancel, "Generally supported with exceptions. User ring optimizations are not implemented.", []string{"gvisor.dev/issue/204"}),
4: syscalls.PartiallySupported("io_getevents", IoGetevents, "Generally supported with exceptions. User ring optimizations are not implemented.", []string{"gvisor.dev/issue/204"}),
- 5: syscalls.Error("setxattr", syserror.ENOTSUP, "Requires filesystem support.", nil),
+ 5: syscalls.PartiallySupported("setxattr", Setxattr, "Only supported for tmpfs.", nil),
6: syscalls.Error("lsetxattr", syserror.ENOTSUP, "Requires filesystem support.", nil),
7: syscalls.Error("fsetxattr", syserror.ENOTSUP, "Requires filesystem support.", nil),
- 8: syscalls.ErrorWithEvent("getxattr", syserror.ENOTSUP, "Requires filesystem support.", nil),
+ 8: syscalls.PartiallySupported("getxattr", Getxattr, "Only supported for tmpfs.", nil),
9: syscalls.ErrorWithEvent("lgetxattr", syserror.ENOTSUP, "Requires filesystem support.", nil),
10: syscalls.ErrorWithEvent("fgetxattr", syserror.ENOTSUP, "Requires filesystem support.", nil),
11: syscalls.ErrorWithEvent("listxattr", syserror.ENOTSUP, "Requires filesystem support.", nil),
diff --git a/pkg/sentry/syscalls/linux/sys_xattr.go b/pkg/sentry/syscalls/linux/sys_xattr.go
new file mode 100755
index 000000000..97d9a65ea
--- /dev/null
+++ b/pkg/sentry/syscalls/linux/sys_xattr.go
@@ -0,0 +1,169 @@
+// Copyright 2019 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 linux
+
+import (
+ "strings"
+
+ "gvisor.dev/gvisor/pkg/abi/linux"
+ "gvisor.dev/gvisor/pkg/sentry/arch"
+ "gvisor.dev/gvisor/pkg/sentry/fs"
+ "gvisor.dev/gvisor/pkg/sentry/kernel"
+ "gvisor.dev/gvisor/pkg/sentry/usermem"
+ "gvisor.dev/gvisor/pkg/syserror"
+)
+
+// Getxattr implements linux syscall getxattr(2).
+func Getxattr(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+ pathAddr := args[0].Pointer()
+ nameAddr := args[1].Pointer()
+ valueAddr := args[2].Pointer()
+ size := args[3].SizeT()
+
+ path, dirPath, err := copyInPath(t, pathAddr, false /* allowEmpty */)
+ if err != nil {
+ return 0, nil, err
+ }
+
+ valueLen := 0
+ err = fileOpOn(t, linux.AT_FDCWD, path, true /* resolve */, func(root *fs.Dirent, d *fs.Dirent, _ uint) error {
+ value, err := getxattr(t, d, dirPath, nameAddr)
+ if err != nil {
+ return err
+ }
+
+ valueLen = len(value)
+ if size == 0 {
+ return nil
+ }
+ if size > linux.XATTR_SIZE_MAX {
+ size = linux.XATTR_SIZE_MAX
+ }
+ if valueLen > int(size) {
+ return syserror.ERANGE
+ }
+
+ _, err = t.CopyOutBytes(valueAddr, []byte(value))
+ return err
+ })
+ if err != nil {
+ return 0, nil, err
+ }
+ return uintptr(valueLen), nil, nil
+}
+
+// getxattr implements getxattr from the given *fs.Dirent.
+func getxattr(t *kernel.Task, d *fs.Dirent, dirPath bool, nameAddr usermem.Addr) (string, error) {
+ if dirPath && !fs.IsDir(d.Inode.StableAttr) {
+ return "", syserror.ENOTDIR
+ }
+
+ if err := checkXattrPermissions(t, d.Inode, fs.PermMask{Read: true}); err != nil {
+ return "", err
+ }
+
+ name, err := copyInXattrName(t, nameAddr)
+ if err != nil {
+ return "", err
+ }
+
+ if !strings.HasPrefix(name, linux.XATTR_USER_PREFIX) {
+ return "", syserror.EOPNOTSUPP
+ }
+
+ return d.Inode.Getxattr(name)
+}
+
+// Setxattr implements linux syscall setxattr(2).
+func Setxattr(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+ pathAddr := args[0].Pointer()
+ nameAddr := args[1].Pointer()
+ valueAddr := args[2].Pointer()
+ size := args[3].SizeT()
+ flags := args[4].Uint()
+
+ path, dirPath, err := copyInPath(t, pathAddr, false /* allowEmpty */)
+ if err != nil {
+ return 0, nil, err
+ }
+
+ if flags&^(linux.XATTR_CREATE|linux.XATTR_REPLACE) != 0 {
+ return 0, nil, syserror.EINVAL
+ }
+
+ return 0, nil, fileOpOn(t, linux.AT_FDCWD, path, true /* resolve */, func(root *fs.Dirent, d *fs.Dirent, _ uint) error {
+ return setxattr(t, d, dirPath, nameAddr, valueAddr, size, flags)
+ })
+}
+
+// setxattr implements setxattr from the given *fs.Dirent.
+func setxattr(t *kernel.Task, d *fs.Dirent, dirPath bool, nameAddr, valueAddr usermem.Addr, size uint, flags uint32) error {
+ if dirPath && !fs.IsDir(d.Inode.StableAttr) {
+ return syserror.ENOTDIR
+ }
+
+ if err := checkXattrPermissions(t, d.Inode, fs.PermMask{Write: true}); err != nil {
+ return err
+ }
+
+ name, err := copyInXattrName(t, nameAddr)
+ if err != nil {
+ return err
+ }
+
+ if size > linux.XATTR_SIZE_MAX {
+ return syserror.E2BIG
+ }
+ buf := make([]byte, size)
+ if _, err = t.CopyInBytes(valueAddr, buf); err != nil {
+ return err
+ }
+ value := string(buf)
+
+ if !strings.HasPrefix(name, linux.XATTR_USER_PREFIX) {
+ return syserror.EOPNOTSUPP
+ }
+
+ return d.Inode.Setxattr(name, value)
+}
+
+func copyInXattrName(t *kernel.Task, nameAddr usermem.Addr) (string, error) {
+ name, err := t.CopyInString(nameAddr, linux.XATTR_NAME_MAX+1)
+ if err != nil {
+ if err == syserror.ENAMETOOLONG {
+ return "", syserror.ERANGE
+ }
+ return "", err
+ }
+ if len(name) == 0 {
+ return "", syserror.ERANGE
+ }
+ return name, nil
+}
+
+func checkXattrPermissions(t *kernel.Task, i *fs.Inode, perms fs.PermMask) error {
+ // Restrict xattrs to regular files and directories.
+ //
+ // In Linux, this restriction technically only applies to xattrs in the
+ // "user.*" namespace, but we don't allow any other xattr prefixes anyway.
+ if !fs.IsRegular(i.StableAttr) && !fs.IsDir(i.StableAttr) {
+ if perms.Write {
+ return syserror.EPERM
+ }
+ return syserror.ENODATA
+ }
+
+ return i.CheckPermission(t, perms)
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-14 16:16:00 +0000