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-rw-r--r--pkg/sentry/fs/copy_up.go2
-rw-r--r--pkg/sentry/fs/fsutil/inode.go20
-rw-r--r--pkg/sentry/fs/gofer/context_file.go14
-rw-r--r--pkg/sentry/fs/gofer/inode.go13
-rw-r--r--pkg/sentry/fs/inode.go14
-rw-r--r--pkg/sentry/fs/inode_operations.go13
-rw-r--r--pkg/sentry/fs/inode_overlay.go18
-rw-r--r--pkg/sentry/fs/tmpfs/tmpfs.go9
-rwxr-xr-xpkg/sentry/syscalls/linux/linux64_amd64.go27
-rwxr-xr-xpkg/sentry/syscalls/linux/linux64_arm64.go37
-rwxr-xr-xpkg/sentry/syscalls/linux/sys_xattr.go200
11 files changed, 307 insertions, 60 deletions
diff --git a/pkg/sentry/fs/copy_up.go b/pkg/sentry/fs/copy_up.go
index f6c79e51b..b060a12ff 100644
--- a/pkg/sentry/fs/copy_up.go
+++ b/pkg/sentry/fs/copy_up.go
@@ -401,7 +401,7 @@ func copyAttributesLocked(ctx context.Context, upper *Inode, lower *Inode) error
if err != nil {
return err
}
- lowerXattr, err := lower.ListXattr(ctx)
+ lowerXattr, err := lower.ListXattr(ctx, linux.XATTR_SIZE_MAX)
if err != nil && err != syserror.EOPNOTSUPP {
return err
}
diff --git a/pkg/sentry/fs/fsutil/inode.go b/pkg/sentry/fs/fsutil/inode.go
index 252830572..daecc4ffe 100644
--- a/pkg/sentry/fs/fsutil/inode.go
+++ b/pkg/sentry/fs/fsutil/inode.go
@@ -247,7 +247,7 @@ func (i *InodeSimpleExtendedAttributes) SetXattr(_ context.Context, _ *fs.Inode,
}
// ListXattr implements fs.InodeOperations.ListXattr.
-func (i *InodeSimpleExtendedAttributes) ListXattr(context.Context, *fs.Inode) (map[string]struct{}, error) {
+func (i *InodeSimpleExtendedAttributes) ListXattr(context.Context, *fs.Inode, uint64) (map[string]struct{}, error) {
i.mu.RLock()
names := make(map[string]struct{}, len(i.xattrs))
for name := range i.xattrs {
@@ -257,6 +257,17 @@ func (i *InodeSimpleExtendedAttributes) ListXattr(context.Context, *fs.Inode) (m
return names, nil
}
+// RemoveXattr implements fs.InodeOperations.RemoveXattr.
+func (i *InodeSimpleExtendedAttributes) RemoveXattr(_ context.Context, _ *fs.Inode, name string) error {
+ i.mu.RLock()
+ defer i.mu.RUnlock()
+ if _, ok := i.xattrs[name]; ok {
+ delete(i.xattrs, name)
+ return nil
+ }
+ return syserror.ENOATTR
+}
+
// staticFile is a file with static contents. It is returned by
// InodeStaticFileGetter.GetFile.
//
@@ -460,10 +471,15 @@ func (InodeNoExtendedAttributes) SetXattr(context.Context, *fs.Inode, string, st
}
// ListXattr implements fs.InodeOperations.ListXattr.
-func (InodeNoExtendedAttributes) ListXattr(context.Context, *fs.Inode) (map[string]struct{}, error) {
+func (InodeNoExtendedAttributes) ListXattr(context.Context, *fs.Inode, uint64) (map[string]struct{}, error) {
return nil, syserror.EOPNOTSUPP
}
+// RemoveXattr implements fs.InodeOperations.RemoveXattr.
+func (InodeNoExtendedAttributes) RemoveXattr(context.Context, *fs.Inode, string) error {
+ return syserror.EOPNOTSUPP
+}
+
// InodeNoopRelease implements fs.InodeOperations.Release as a noop.
type InodeNoopRelease struct{}
diff --git a/pkg/sentry/fs/gofer/context_file.go b/pkg/sentry/fs/gofer/context_file.go
index 3da818aed..125907d70 100644
--- a/pkg/sentry/fs/gofer/context_file.go
+++ b/pkg/sentry/fs/gofer/context_file.go
@@ -73,6 +73,20 @@ func (c *contextFile) setXattr(ctx context.Context, name, value string, flags ui
return err
}
+func (c *contextFile) listXattr(ctx context.Context, size uint64) (map[string]struct{}, error) {
+ ctx.UninterruptibleSleepStart(false)
+ xattrs, err := c.file.ListXattr(size)
+ ctx.UninterruptibleSleepFinish(false)
+ return xattrs, err
+}
+
+func (c *contextFile) removeXattr(ctx context.Context, name string) error {
+ ctx.UninterruptibleSleepStart(false)
+ err := c.file.RemoveXattr(name)
+ ctx.UninterruptibleSleepFinish(false)
+ return err
+}
+
func (c *contextFile) allocate(ctx context.Context, mode p9.AllocateMode, offset, length uint64) error {
ctx.UninterruptibleSleepStart(false)
err := c.file.Allocate(mode, offset, length)
diff --git a/pkg/sentry/fs/gofer/inode.go b/pkg/sentry/fs/gofer/inode.go
index ac28174d2..1c934981b 100644
--- a/pkg/sentry/fs/gofer/inode.go
+++ b/pkg/sentry/fs/gofer/inode.go
@@ -604,18 +604,23 @@ func (i *inodeOperations) Truncate(ctx context.Context, inode *fs.Inode, length
}
// GetXattr implements fs.InodeOperations.GetXattr.
-func (i *inodeOperations) GetXattr(ctx context.Context, inode *fs.Inode, name string, size uint64) (string, error) {
+func (i *inodeOperations) GetXattr(ctx context.Context, _ *fs.Inode, name string, size uint64) (string, error) {
return i.fileState.file.getXattr(ctx, name, size)
}
// SetXattr implements fs.InodeOperations.SetXattr.
-func (i *inodeOperations) SetXattr(ctx context.Context, inode *fs.Inode, name string, value string, flags uint32) error {
+func (i *inodeOperations) SetXattr(ctx context.Context, _ *fs.Inode, name string, value string, flags uint32) error {
return i.fileState.file.setXattr(ctx, name, value, flags)
}
// ListXattr implements fs.InodeOperations.ListXattr.
-func (i *inodeOperations) ListXattr(context.Context, *fs.Inode) (map[string]struct{}, error) {
- return nil, syscall.EOPNOTSUPP
+func (i *inodeOperations) ListXattr(ctx context.Context, _ *fs.Inode, size uint64) (map[string]struct{}, error) {
+ return i.fileState.file.listXattr(ctx, size)
+}
+
+// RemoveXattr implements fs.InodeOperations.RemoveXattr.
+func (i *inodeOperations) RemoveXattr(ctx context.Context, _ *fs.Inode, name string) error {
+ return i.fileState.file.removeXattr(ctx, name)
}
// Allocate implements fs.InodeOperations.Allocate.
diff --git a/pkg/sentry/fs/inode.go b/pkg/sentry/fs/inode.go
index b66c091ab..55fb71c16 100644
--- a/pkg/sentry/fs/inode.go
+++ b/pkg/sentry/fs/inode.go
@@ -278,11 +278,19 @@ func (i *Inode) SetXattr(ctx context.Context, d *Dirent, name, value string, fla
}
// ListXattr calls i.InodeOperations.ListXattr with i as the Inode.
-func (i *Inode) ListXattr(ctx context.Context) (map[string]struct{}, error) {
+func (i *Inode) ListXattr(ctx context.Context, size uint64) (map[string]struct{}, error) {
if i.overlay != nil {
- return overlayListXattr(ctx, i.overlay)
+ return overlayListXattr(ctx, i.overlay, size)
}
- return i.InodeOperations.ListXattr(ctx, i)
+ return i.InodeOperations.ListXattr(ctx, i, size)
+}
+
+// RemoveXattr calls i.InodeOperations.RemoveXattr with i as the Inode.
+func (i *Inode) RemoveXattr(ctx context.Context, d *Dirent, name string) error {
+ if i.overlay != nil {
+ return overlayRemoveXattr(ctx, i.overlay, d, name)
+ }
+ return i.InodeOperations.RemoveXattr(ctx, i, name)
}
// CheckPermission will check if the caller may access this file in the
diff --git a/pkg/sentry/fs/inode_operations.go b/pkg/sentry/fs/inode_operations.go
index 70f2eae96..2bbfb72ef 100644
--- a/pkg/sentry/fs/inode_operations.go
+++ b/pkg/sentry/fs/inode_operations.go
@@ -190,7 +190,18 @@ type InodeOperations interface {
// ListXattr returns the set of all extended attributes names that
// have values. Inodes that do not support extended attributes return
// EOPNOTSUPP.
- ListXattr(ctx context.Context, inode *Inode) (map[string]struct{}, error)
+ //
+ // If this is called through the listxattr(2) syscall, size indicates the
+ // size of the buffer that the application has allocated to hold the
+ // attribute list. If the list would be larger than size, implementations may
+ // return ERANGE to indicate that the buffer is too small, but they are also
+ // free to ignore the hint entirely. All size checking is done independently
+ // at the syscall layer.
+ ListXattr(ctx context.Context, inode *Inode, size uint64) (map[string]struct{}, error)
+
+ // RemoveXattr removes an extended attribute specified by name. Inodes that
+ // do not support extended attributes return EOPNOTSUPP.
+ RemoveXattr(ctx context.Context, inode *Inode, name string) error
// Check determines whether an Inode can be accessed with the
// requested permission mask using the context (which gives access
diff --git a/pkg/sentry/fs/inode_overlay.go b/pkg/sentry/fs/inode_overlay.go
index 4729b4aac..5ada33a32 100644
--- a/pkg/sentry/fs/inode_overlay.go
+++ b/pkg/sentry/fs/inode_overlay.go
@@ -564,15 +564,15 @@ func overlaySetxattr(ctx context.Context, o *overlayEntry, d *Dirent, name, valu
return o.upper.SetXattr(ctx, d, name, value, flags)
}
-func overlayListXattr(ctx context.Context, o *overlayEntry) (map[string]struct{}, error) {
+func overlayListXattr(ctx context.Context, o *overlayEntry, size uint64) (map[string]struct{}, error) {
o.copyMu.RLock()
defer o.copyMu.RUnlock()
var names map[string]struct{}
var err error
if o.upper != nil {
- names, err = o.upper.ListXattr(ctx)
+ names, err = o.upper.ListXattr(ctx, size)
} else {
- names, err = o.lower.ListXattr(ctx)
+ names, err = o.lower.ListXattr(ctx, size)
}
for name := range names {
// Same as overlayGetXattr, we shouldn't forward along
@@ -584,6 +584,18 @@ func overlayListXattr(ctx context.Context, o *overlayEntry) (map[string]struct{}
return names, err
}
+func overlayRemoveXattr(ctx context.Context, o *overlayEntry, d *Dirent, name string) error {
+ // Don't allow changes to overlay xattrs through a removexattr syscall.
+ if strings.HasPrefix(XattrOverlayPrefix, name) {
+ return syserror.EPERM
+ }
+
+ if err := copyUp(ctx, d); err != nil {
+ return err
+ }
+ return o.upper.RemoveXattr(ctx, d, name)
+}
+
func overlayCheck(ctx context.Context, o *overlayEntry, p PermMask) error {
o.copyMu.RLock()
// Hot path. Avoid defers.
diff --git a/pkg/sentry/fs/tmpfs/tmpfs.go b/pkg/sentry/fs/tmpfs/tmpfs.go
index c00cef0a5..3c2b583ae 100644
--- a/pkg/sentry/fs/tmpfs/tmpfs.go
+++ b/pkg/sentry/fs/tmpfs/tmpfs.go
@@ -159,8 +159,13 @@ func (d *Dir) SetXattr(ctx context.Context, i *fs.Inode, name, value string, fla
}
// ListXattr implements fs.InodeOperations.ListXattr.
-func (d *Dir) ListXattr(ctx context.Context, i *fs.Inode) (map[string]struct{}, error) {
- return d.ramfsDir.ListXattr(ctx, i)
+func (d *Dir) ListXattr(ctx context.Context, i *fs.Inode, size uint64) (map[string]struct{}, error) {
+ return d.ramfsDir.ListXattr(ctx, i, size)
+}
+
+// RemoveXattr implements fs.InodeOperations.RemoveXattr.
+func (d *Dir) RemoveXattr(ctx context.Context, i *fs.Inode, name string) error {
+ return d.ramfsDir.RemoveXattr(ctx, i, name)
}
// Lookup implements fs.InodeOperations.Lookup.
diff --git a/pkg/sentry/syscalls/linux/linux64_amd64.go b/pkg/sentry/syscalls/linux/linux64_amd64.go
index 588f8b087..79066ad2a 100755
--- a/pkg/sentry/syscalls/linux/linux64_amd64.go
+++ b/pkg/sentry/syscalls/linux/linux64_amd64.go
@@ -228,21 +228,18 @@ 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),
- // TODO(b/148303075): Enable set/getxattr (in their various
- // forms) once we also have list and removexattr. The JVM
- // assumes that if get/set exist, then list and remove do too.
- 188: syscalls.ErrorWithEvent("setxattr", syserror.ENOTSUP, "Requires filesystem support.", []string{"gvisor.dev/issue/1636"}),
- 189: syscalls.ErrorWithEvent("lsetxattr", syserror.ENOTSUP, "Requires filesystem support.", []string{"gvisor.dev/issue/1636"}),
- 190: syscalls.ErrorWithEvent("fsetxattr", syserror.ENOTSUP, "Requires filesystem support.", []string{"gvisor.dev/issue/1636"}),
- 191: syscalls.ErrorWithEvent("getxattr", syserror.ENOTSUP, "Requires filesystem support.", []string{"gvisor.dev/issue/1636"}),
- 192: syscalls.ErrorWithEvent("lgetxattr", syserror.ENOTSUP, "Requires filesystem support.", []string{"gvisor.dev/issue/1636"}),
- 193: syscalls.ErrorWithEvent("fgetxattr", syserror.ENOTSUP, "Requires filesystem support.", []string{"gvisor.dev/issue/1636"}),
- 194: syscalls.ErrorWithEvent("listxattr", syserror.ENOTSUP, "Requires filesystem support.", []string{"gvisor.dev/issue/1636"}),
- 195: syscalls.ErrorWithEvent("llistxattr", syserror.ENOTSUP, "Requires filesystem support.", []string{"gvisor.dev/issue/1636"}),
- 196: syscalls.ErrorWithEvent("flistxattr", syserror.ENOTSUP, "Requires filesystem support.", []string{"gvisor.dev/issue/1636"}),
- 197: syscalls.ErrorWithEvent("removexattr", syserror.ENOTSUP, "Requires filesystem support.", []string{"gvisor.dev/issue/1636"}),
- 198: syscalls.ErrorWithEvent("lremovexattr", syserror.ENOTSUP, "Requires filesystem support.", []string{"gvisor.dev/issue/1636"}),
- 199: syscalls.ErrorWithEvent("fremovexattr", syserror.ENOTSUP, "Requires filesystem support.", []string{"gvisor.dev/issue/1636"}),
+ 188: syscalls.PartiallySupported("setxattr", SetXattr, "Only supported for tmpfs.", nil),
+ 189: syscalls.PartiallySupported("lsetxattr", LSetXattr, "Only supported for tmpfs.", nil),
+ 190: syscalls.PartiallySupported("fsetxattr", FSetXattr, "Only supported for tmpfs.", nil),
+ 191: syscalls.PartiallySupported("getxattr", GetXattr, "Only supported for tmpfs.", nil),
+ 192: syscalls.PartiallySupported("lgetxattr", LGetXattr, "Only supported for tmpfs.", nil),
+ 193: syscalls.PartiallySupported("fgetxattr", FGetXattr, "Only supported for tmpfs.", nil),
+ 194: syscalls.PartiallySupported("listxattr", ListXattr, "Only supported for tmpfs", nil),
+ 195: syscalls.PartiallySupported("llistxattr", LListXattr, "Only supported for tmpfs", nil),
+ 196: syscalls.PartiallySupported("flistxattr", FListXattr, "Only supported for tmpfs", nil),
+ 197: syscalls.PartiallySupported("removexattr", RemoveXattr, "Only supported for tmpfs", nil),
+ 198: syscalls.PartiallySupported("lremovexattr", LRemoveXattr, "Only supported for tmpfs", nil),
+ 199: syscalls.PartiallySupported("fremovexattr", FRemoveXattr, "Only supported for tmpfs", nil),
200: syscalls.Supported("tkill", Tkill),
201: syscalls.Supported("time", Time),
202: syscalls.PartiallySupported("futex", Futex, "Robust futexes not supported.", nil),
diff --git a/pkg/sentry/syscalls/linux/linux64_arm64.go b/pkg/sentry/syscalls/linux/linux64_arm64.go
index 06e5ee401..7421619de 100755
--- a/pkg/sentry/syscalls/linux/linux64_arm64.go
+++ b/pkg/sentry/syscalls/linux/linux64_arm64.go
@@ -36,26 +36,23 @@ var ARM64 = &kernel.SyscallTable{
},
AuditNumber: linux.AUDIT_ARCH_AARCH64,
Table: map[uintptr]kernel.Syscall{
- 0: syscalls.PartiallySupported("io_setup", IoSetup, "Generally supported with exceptions. User ring optimizations are not implemented.", []string{"gvisor.dev/issue/204"}),
- 1: syscalls.PartiallySupported("io_destroy", IoDestroy, "Generally supported with exceptions. User ring optimizations are not implemented.", []string{"gvisor.dev/issue/204"}),
- 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"}),
- // TODO(b/148303075): Enable set/getxattr (in their various
- // forms) once we also have list and removexattr. The JVM
- // assumes that if get/set exist, then list and remove do too.
- 5: syscalls.ErrorWithEvent("setxattr", syserror.ENOTSUP, "Requires filesystem support.", []string{"gvisor.dev/issue/1636"}),
- 6: syscalls.ErrorWithEvent("lsetxattr", syserror.ENOTSUP, "Requires filesystem support.", []string{"gvisor.dev/issue/1636"}),
- 7: syscalls.ErrorWithEvent("fsetxattr", syserror.ENOTSUP, "Requires filesystem support.", []string{"gvisor.dev/issue/1636"}),
- 8: syscalls.ErrorWithEvent("getxattr", syserror.ENOTSUP, "Requires filesystem support.", []string{"gvisor.dev/issue/1636"}),
- 9: syscalls.ErrorWithEvent("lgetxattr", syserror.ENOTSUP, "Requires filesystem support.", []string{"gvisor.dev/issue/1636"}),
- 10: syscalls.ErrorWithEvent("fgetxattr", syserror.ENOTSUP, "Requires filesystem support.", []string{"gvisor.dev/issue/1636"}),
- 11: syscalls.ErrorWithEvent("listxattr", syserror.ENOTSUP, "Requires filesystem support.", []string{"gvisor.dev/issue/1636"}),
- 13: syscalls.ErrorWithEvent("llistxattr", syserror.ENOTSUP, "Requires filesystem support.", []string{"gvisor.dev/issue/1636"}),
- 13: syscalls.ErrorWithEvent("flistxattr", syserror.ENOTSUP, "Requires filesystem support.", []string{"gvisor.dev/issue/1636"}),
- 14: syscalls.ErrorWithEvent("removexattr", syserror.ENOTSUP, "Requires filesystem support.", []string{"gvisor.dev/issue/1636"}),
- 15: syscalls.ErrorWithEvent("lremovexattr", syserror.ENOTSUP, "Requires filesystem support.", []string{"gvisor.dev/issue/1636"}),
- 16: syscalls.ErrorWithEvent("fremovexattr", syserror.ENOTSUP, "Requires filesystem support.", []string{"gvisor.dev/issue/1636"}),
+ 0: syscalls.PartiallySupported("io_setup", IoSetup, "Generally supported with exceptions. User ring optimizations are not implemented.", []string{"gvisor.dev/issue/204"}),
+ 1: syscalls.PartiallySupported("io_destroy", IoDestroy, "Generally supported with exceptions. User ring optimizations are not implemented.", []string{"gvisor.dev/issue/204"}),
+ 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.PartiallySupported("setxattr", SetXattr, "Only supported for tmpfs.", nil),
+ 6: syscalls.PartiallySupported("lsetxattr", LSetXattr, "Only supported for tmpfs.", nil),
+ 7: syscalls.PartiallySupported("fsetxattr", FSetXattr, "Only supported for tmpfs.", nil),
+ 8: syscalls.PartiallySupported("getxattr", GetXattr, "Only supported for tmpfs.", nil),
+ 9: syscalls.PartiallySupported("lgetxattr", LGetXattr, "Only supported for tmpfs.", nil),
+ 10: syscalls.PartiallySupported("fgetxattr", FGetXattr, "Only supported for tmpfs.", nil),
+ 11: syscalls.PartiallySupported("listxattr", ListXattr, "Only supported for tmpfs", nil),
+ 12: syscalls.PartiallySupported("llistxattr", LListXattr, "Only supported for tmpfs", nil),
+ 13: syscalls.PartiallySupported("flistxattr", FListXattr, "Only supported for tmpfs", nil),
+ 14: syscalls.PartiallySupported("removexattr", RemoveXattr, "Only supported for tmpfs", nil),
+ 15: syscalls.PartiallySupported("lremovexattr", LRemoveXattr, "Only supported for tmpfs", nil),
+ 16: syscalls.PartiallySupported("fremovexattr", FRemoveXattr, "Only supported for tmpfs", nil),
17: syscalls.Supported("getcwd", Getcwd),
18: syscalls.CapError("lookup_dcookie", linux.CAP_SYS_ADMIN, "", nil),
19: syscalls.Supported("eventfd2", Eventfd2),
diff --git a/pkg/sentry/syscalls/linux/sys_xattr.go b/pkg/sentry/syscalls/linux/sys_xattr.go
index efb95555c..342337726 100755
--- a/pkg/sentry/syscalls/linux/sys_xattr.go
+++ b/pkg/sentry/syscalls/linux/sys_xattr.go
@@ -72,7 +72,7 @@ func getXattrFromPath(t *kernel.Task, args arch.SyscallArguments, resolveSymlink
}
valueLen := 0
- err = fileOpOn(t, linux.AT_FDCWD, path, resolveSymlink, func(root *fs.Dirent, d *fs.Dirent, _ uint) error {
+ err = fileOpOn(t, linux.AT_FDCWD, path, resolveSymlink, func(_ *fs.Dirent, d *fs.Dirent, _ uint) error {
if dirPath && !fs.IsDir(d.Inode.StableAttr) {
return syserror.ENOTDIR
}
@@ -172,7 +172,7 @@ func setXattrFromPath(t *kernel.Task, args arch.SyscallArguments, resolveSymlink
return 0, nil, err
}
- return 0, nil, fileOpOn(t, linux.AT_FDCWD, path, resolveSymlink, func(root *fs.Dirent, d *fs.Dirent, _ uint) error {
+ return 0, nil, fileOpOn(t, linux.AT_FDCWD, path, resolveSymlink, func(_ *fs.Dirent, d *fs.Dirent, _ uint) error {
if dirPath && !fs.IsDir(d.Inode.StableAttr) {
return syserror.ENOTDIR
}
@@ -187,12 +187,12 @@ func setXattr(t *kernel.Task, d *fs.Dirent, nameAddr, valueAddr usermem.Addr, si
return syserror.EINVAL
}
- if err := checkXattrPermissions(t, d.Inode, fs.PermMask{Write: true}); err != nil {
+ name, err := copyInXattrName(t, nameAddr)
+ if err != nil {
return err
}
- name, err := copyInXattrName(t, nameAddr)
- if err != nil {
+ if err := checkXattrPermissions(t, d.Inode, fs.PermMask{Write: true}); err != nil {
return err
}
@@ -226,12 +226,18 @@ func copyInXattrName(t *kernel.Task, nameAddr usermem.Addr) (string, error) {
return name, nil
}
+// Restrict xattrs to regular files and directories.
+//
+// TODO(b/148380782): In Linux, this restriction technically only applies to
+// xattrs in the "user.*" namespace. Make file type checks specific to the
+// namespace once we allow other xattr prefixes.
+func xattrFileTypeOk(i *fs.Inode) bool {
+ return fs.IsRegular(i.StableAttr) || fs.IsDir(i.StableAttr)
+}
+
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 !xattrFileTypeOk(i) {
if perms.Write {
return syserror.EPERM
}
@@ -240,3 +246,179 @@ func checkXattrPermissions(t *kernel.Task, i *fs.Inode, perms fs.PermMask) error
return i.CheckPermission(t, perms)
}
+
+// ListXattr implements linux syscall listxattr(2).
+func ListXattr(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+ return listXattrFromPath(t, args, true)
+}
+
+// LListXattr implements linux syscall llistxattr(2).
+func LListXattr(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+ return listXattrFromPath(t, args, false)
+}
+
+// FListXattr implements linux syscall flistxattr(2).
+func FListXattr(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+ fd := args[0].Int()
+ listAddr := args[1].Pointer()
+ size := uint64(args[2].SizeT())
+
+ // TODO(b/113957122): Return EBADF if the fd was opened with O_PATH.
+ f := t.GetFile(fd)
+ if f == nil {
+ return 0, nil, syserror.EBADF
+ }
+ defer f.DecRef()
+
+ n, err := listXattr(t, f.Dirent, listAddr, size)
+ if err != nil {
+ return 0, nil, err
+ }
+
+ return uintptr(n), nil, nil
+}
+
+func listXattrFromPath(t *kernel.Task, args arch.SyscallArguments, resolveSymlink bool) (uintptr, *kernel.SyscallControl, error) {
+ pathAddr := args[0].Pointer()
+ listAddr := args[1].Pointer()
+ size := uint64(args[2].SizeT())
+
+ path, dirPath, err := copyInPath(t, pathAddr, false /* allowEmpty */)
+ if err != nil {
+ return 0, nil, err
+ }
+
+ n := 0
+ err = fileOpOn(t, linux.AT_FDCWD, path, resolveSymlink, func(_ *fs.Dirent, d *fs.Dirent, _ uint) error {
+ if dirPath && !fs.IsDir(d.Inode.StableAttr) {
+ return syserror.ENOTDIR
+ }
+
+ n, err = listXattr(t, d, listAddr, size)
+ return err
+ })
+ if err != nil {
+ return 0, nil, err
+ }
+
+ return uintptr(n), nil, nil
+}
+
+func listXattr(t *kernel.Task, d *fs.Dirent, addr usermem.Addr, size uint64) (int, error) {
+ if !xattrFileTypeOk(d.Inode) {
+ return 0, nil
+ }
+
+ // If listxattr(2) is called with size 0, the buffer size needed to contain
+ // the xattr list will be returned successfully even if it is nonzero. In
+ // that case, we need to retrieve the entire list so we can compute and
+ // return the correct size.
+ requestedSize := size
+ if size == 0 || size > linux.XATTR_SIZE_MAX {
+ requestedSize = linux.XATTR_SIZE_MAX
+ }
+ xattrs, err := d.Inode.ListXattr(t, requestedSize)
+ if err != nil {
+ return 0, err
+ }
+
+ // TODO(b/148380782): support namespaces other than "user".
+ for x := range xattrs {
+ if !strings.HasPrefix(x, linux.XATTR_USER_PREFIX) {
+ delete(xattrs, x)
+ }
+ }
+
+ listSize := xattrListSize(xattrs)
+ if listSize > linux.XATTR_SIZE_MAX {
+ return 0, syserror.E2BIG
+ }
+ if uint64(listSize) > requestedSize {
+ return 0, syserror.ERANGE
+ }
+
+ // Don't copy out the attributes if size is 0.
+ if size == 0 {
+ return listSize, nil
+ }
+
+ buf := make([]byte, 0, listSize)
+ for x := range xattrs {
+ buf = append(buf, []byte(x)...)
+ buf = append(buf, 0)
+ }
+ if _, err := t.CopyOutBytes(addr, buf); err != nil {
+ return 0, err
+ }
+
+ return len(buf), nil
+}
+
+func xattrListSize(xattrs map[string]struct{}) int {
+ size := 0
+ for x := range xattrs {
+ size += len(x) + 1
+ }
+ return size
+}
+
+// RemoveXattr implements linux syscall removexattr(2).
+func RemoveXattr(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+ return removeXattrFromPath(t, args, true)
+}
+
+// LRemoveXattr implements linux syscall lremovexattr(2).
+func LRemoveXattr(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+ return removeXattrFromPath(t, args, false)
+}
+
+// FRemoveXattr implements linux syscall fremovexattr(2).
+func FRemoveXattr(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+ fd := args[0].Int()
+ nameAddr := args[1].Pointer()
+
+ // TODO(b/113957122): Return EBADF if the fd was opened with O_PATH.
+ f := t.GetFile(fd)
+ if f == nil {
+ return 0, nil, syserror.EBADF
+ }
+ defer f.DecRef()
+
+ return 0, nil, removeXattr(t, f.Dirent, nameAddr)
+}
+
+func removeXattrFromPath(t *kernel.Task, args arch.SyscallArguments, resolveSymlink bool) (uintptr, *kernel.SyscallControl, error) {
+ pathAddr := args[0].Pointer()
+ nameAddr := args[1].Pointer()
+
+ path, dirPath, err := copyInPath(t, pathAddr, false /* allowEmpty */)
+ if err != nil {
+ return 0, nil, err
+ }
+
+ return 0, nil, fileOpOn(t, linux.AT_FDCWD, path, resolveSymlink, func(_ *fs.Dirent, d *fs.Dirent, _ uint) error {
+ if dirPath && !fs.IsDir(d.Inode.StableAttr) {
+ return syserror.ENOTDIR
+ }
+
+ return removeXattr(t, d, nameAddr)
+ })
+}
+
+// removeXattr implements removexattr(2) from the given *fs.Dirent.
+func removeXattr(t *kernel.Task, d *fs.Dirent, nameAddr usermem.Addr) error {
+ name, err := copyInXattrName(t, nameAddr)
+ if err != nil {
+ return err
+ }
+
+ if err := checkXattrPermissions(t, d.Inode, fs.PermMask{Write: true}); err != nil {
+ return err
+ }
+
+ if !strings.HasPrefix(name, linux.XATTR_USER_PREFIX) {
+ return syserror.EOPNOTSUPP
+ }
+
+ return d.Inode.RemoveXattr(t, d, name)
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-24 10:58:45 +0000