Use storage that better supports rootless overlayfs

overlayfs -- the kernel's version, not fuse-overlayfs -- recently learned
(as of linux 5.16.0, I believe) how to support rootless users. Previously,
rootless users had to use these storage.conf(5) settings:

* storage.driver=vfs          (aka STORAGE_DRIVER=vfs), or
* storage.driver=overlay      (aka STORAGE_DRIVER=overlay),
  storage.options.overlay.mount_program=/usr/bin/fuse-overlayfs
                              (aka STORAGE_OPTS=/usr/bin/fuse-overlayfs)

Now that a third backend is available, setting only:

* storage.driver=overlay      (aka STORAGE_DRIVER=overlay)

https://github.com/containers/podman/issues/13123 reported EXDEV errors
during the normal operation of their container. Tracing it out, the
problem turned out to be that their container was being mounted without
'userxattr'; I don't fully understand why, but mount(8) mentions this is
needed for rootless users:

> userxattr
>
>   Use the "user.overlay." xattr namespace instead of "trusted.overlay.".
>   This is useful for unprivileged mounting of overlayfs.

https://github.com/containers/storage/pull/1156 found and fixed the issue
in podman, and this just pulls in that via

    go get github.com/containers/storage@ebc90ab
    go mod vendor
    make vendor

Closes https://github.com/containers/podman/issues/13123

Signed-off-by: Nick Guenther <nick.guenther@polymtl.ca>
This commit is contained in:
Nick Guenther
2022-02-28 12:54:09 -05:00
parent 8bdda91ab7
commit 572e6464f6
31 changed files with 383 additions and 217 deletions

View File

@@ -14,8 +14,6 @@ import (
"encoding/binary"
"fmt"
"strconv"
"golang.org/x/sys/windows"
)
// Variant specifies which GUID variant (or "type") of the GUID. It determines
@@ -41,13 +39,6 @@ type Version uint8
var _ = (encoding.TextMarshaler)(GUID{})
var _ = (encoding.TextUnmarshaler)(&GUID{})
// GUID represents a GUID/UUID. It has the same structure as
// golang.org/x/sys/windows.GUID so that it can be used with functions expecting
// that type. It is defined as its own type so that stringification and
// marshaling can be supported. The representation matches that used by native
// Windows code.
type GUID windows.GUID
// NewV4 returns a new version 4 (pseudorandom) GUID, as defined by RFC 4122.
func NewV4() (GUID, error) {
var b [16]byte

View File

@@ -0,0 +1,15 @@
// +build !windows
package guid
// GUID represents a GUID/UUID. It has the same structure as
// golang.org/x/sys/windows.GUID so that it can be used with functions expecting
// that type. It is defined as its own type as that is only available to builds
// targeted at `windows`. The representation matches that used by native Windows
// code.
type GUID struct {
Data1 uint32
Data2 uint16
Data3 uint16
Data4 [8]byte
}

View File

@@ -0,0 +1,10 @@
package guid
import "golang.org/x/sys/windows"
// GUID represents a GUID/UUID. It has the same structure as
// golang.org/x/sys/windows.GUID so that it can be used with functions expecting
// that type. It is defined as its own type so that stringification and
// marshaling can be supported. The representation matches that used by native
// Windows code.
type GUID windows.GUID

View File

@@ -3,11 +3,10 @@
package security
import (
"fmt"
"os"
"syscall"
"unsafe"
"github.com/pkg/errors"
)
type (
@@ -72,7 +71,7 @@ func GrantVmGroupAccess(name string) error {
// Stat (to determine if `name` is a directory).
s, err := os.Stat(name)
if err != nil {
return errors.Wrapf(err, "%s os.Stat %s", gvmga, name)
return fmt.Errorf("%s os.Stat %s: %w", gvmga, name, err)
}
// Get a handle to the file/directory. Must defer Close on success.
@@ -88,7 +87,7 @@ func GrantVmGroupAccess(name string) error {
sd := uintptr(0)
origDACL := uintptr(0)
if err := getSecurityInfo(fd, uint32(ot), uint32(si), nil, nil, &origDACL, nil, &sd); err != nil {
return errors.Wrapf(err, "%s GetSecurityInfo %s", gvmga, name)
return fmt.Errorf("%s GetSecurityInfo %s: %w", gvmga, name, err)
}
defer syscall.LocalFree((syscall.Handle)(unsafe.Pointer(sd)))
@@ -102,7 +101,7 @@ func GrantVmGroupAccess(name string) error {
// And finally use SetSecurityInfo to apply the updated DACL.
if err := setSecurityInfo(fd, uint32(ot), uint32(si), uintptr(0), uintptr(0), newDACL, uintptr(0)); err != nil {
return errors.Wrapf(err, "%s SetSecurityInfo %s", gvmga, name)
return fmt.Errorf("%s SetSecurityInfo %s: %w", gvmga, name, err)
}
return nil
@@ -120,7 +119,7 @@ func createFile(name string, isDir bool) (syscall.Handle, error) {
}
fd, err := syscall.CreateFile(&namep[0], da, sm, nil, syscall.OPEN_EXISTING, fa, 0)
if err != nil {
return 0, errors.Wrapf(err, "%s syscall.CreateFile %s", gvmga, name)
return 0, fmt.Errorf("%s syscall.CreateFile %s: %w", gvmga, name, err)
}
return fd, nil
}
@@ -131,7 +130,7 @@ func generateDACLWithAcesAdded(name string, isDir bool, origDACL uintptr) (uintp
// Generate pointers to the SIDs based on the string SIDs
sid, err := syscall.StringToSid(sidVmGroup)
if err != nil {
return 0, errors.Wrapf(err, "%s syscall.StringToSid %s %s", gvmga, name, sidVmGroup)
return 0, fmt.Errorf("%s syscall.StringToSid %s %s: %w", gvmga, name, sidVmGroup, err)
}
inheritance := inheritModeNoInheritance
@@ -154,7 +153,7 @@ func generateDACLWithAcesAdded(name string, isDir bool, origDACL uintptr) (uintp
modifiedDACL := uintptr(0)
if err := setEntriesInAcl(uintptr(uint32(1)), uintptr(unsafe.Pointer(&eaArray[0])), origDACL, &modifiedDACL); err != nil {
return 0, errors.Wrapf(err, "%s SetEntriesInAcl %s", gvmga, name)
return 0, fmt.Errorf("%s SetEntriesInAcl %s: %w", gvmga, name, err)
}
return modifiedDACL, nil