From 93ac040bf0c0b51d9a7fedaf994bf5bf1d68ee0e Mon Sep 17 00:00:00 2001 From: Brian Goff Date: Fri, 2 Jul 2021 17:27:45 +0000 Subject: [PATCH] Lock down docker root dir perms. Do not use 0701 perms. 0701 dir perms allows anyone to traverse the docker dir. It happens to allow any user to execute, as an example, suid binaries from image rootfs dirs because it allows traversal AND critically container users need to be able to do execute things. 0701 on lower directories also happens to allow any user to modify things in, for instance, the overlay upper dir which neccessarily has 0755 permissions. This changes to use 0710 which allows users in the group to traverse. In userns mode the UID owner is (real) root and the GID is the remapped root's GID. This prevents anyone but the remapped root to traverse our directories (which is required for userns with runc). Signed-off-by: Brian Goff (cherry picked from commit ef7237442147441a7cadcda0600be1186d81ac73) Signed-off-by: Brian Goff --- daemon/container_operations_unix.go | 2 +- daemon/create.go | 5 ++-- daemon/daemon.go | 5 +++- daemon/daemon_unix.go | 14 +++++------ daemon/graphdriver/aufs/aufs.go | 13 ++++++++-- daemon/graphdriver/btrfs/btrfs.go | 18 ++++++++++++-- .../fuse-overlayfs/fuseoverlayfs.go | 24 +++++++++++++++---- daemon/graphdriver/overlay/overlay.go | 20 ++++++++++++---- daemon/graphdriver/overlay2/overlay.go | 24 +++++++++++++++---- daemon/graphdriver/vfs/driver.go | 17 +++++++++++-- daemon/graphdriver/zfs/zfs.go | 11 ++++++++- 11 files changed, 121 insertions(+), 32 deletions(-) diff --git a/daemon/container_operations_unix.go b/daemon/container_operations_unix.go index 5521adbd27..1647df0ce7 100644 --- a/daemon/container_operations_unix.go +++ b/daemon/container_operations_unix.go @@ -466,5 +466,5 @@ func (daemon *Daemon) setupContainerMountsRoot(c *container.Container) error { if err != nil { return err } - return idtools.MkdirAllAndChown(p, 0701, idtools.CurrentIdentity()) + return idtools.MkdirAllAndChown(p, 0710, idtools.Identity{UID: idtools.CurrentIdentity().UID, GID: daemon.IdentityMapping().RootPair().GID}) } diff --git a/daemon/create.go b/daemon/create.go index 57f1eff665..b07851aec9 100644 --- a/daemon/create.go +++ b/daemon/create.go @@ -212,10 +212,11 @@ func (daemon *Daemon) create(opts createOpts) (retC *container.Container, retErr } ctr.RWLayer = rwLayer - if err := idtools.MkdirAndChown(ctr.Root, 0701, idtools.CurrentIdentity()); err != nil { + current := idtools.CurrentIdentity() + if err := idtools.MkdirAndChown(ctr.Root, 0710, idtools.Identity{UID: current.UID, GID: daemon.IdentityMapping().RootPair().GID}); err != nil { return nil, err } - if err := idtools.MkdirAndChown(ctr.CheckpointDir(), 0700, idtools.CurrentIdentity()); err != nil { + if err := idtools.MkdirAndChown(ctr.CheckpointDir(), 0700, current); err != nil { return nil, err } diff --git a/daemon/daemon.go b/daemon/daemon.go index 3d8cca2880..2a2fbbd52e 100644 --- a/daemon/daemon.go +++ b/daemon/daemon.go @@ -861,7 +861,10 @@ func NewDaemon(ctx context.Context, config *config.Config, pluginStore *plugin.S } daemonRepo := filepath.Join(config.Root, "containers") - if err := idtools.MkdirAllAndChown(daemonRepo, 0701, idtools.CurrentIdentity()); err != nil { + if err := idtools.MkdirAllAndChown(daemonRepo, 0710, idtools.Identity{ + UID: idtools.CurrentIdentity().UID, + GID: rootIDs.GID, + }); err != nil { return nil, err } diff --git a/daemon/daemon_unix.go b/daemon/daemon_unix.go index 8754d4f972..d982018c34 100644 --- a/daemon/daemon_unix.go +++ b/daemon/daemon_unix.go @@ -1216,21 +1216,21 @@ func setupDaemonRoot(config *config.Config, rootDir string, remappedRoot idtools } } + id := idtools.Identity{UID: idtools.CurrentIdentity().UID, GID: remappedRoot.GID} + // First make sure the current root dir has the correct perms. + if err := idtools.MkdirAllAndChown(config.Root, 0710, id); err != nil { + return errors.Wrapf(err, "could not create or set daemon root permissions: %s", config.Root) + } + // if user namespaces are enabled we will create a subtree underneath the specified root // with any/all specified remapped root uid/gid options on the daemon creating // a new subdirectory with ownership set to the remapped uid/gid (so as to allow // `chdir()` to work for containers namespaced to that uid/gid) if config.RemappedRoot != "" { - id := idtools.CurrentIdentity() - // First make sure the current root dir has the correct perms. - if err := idtools.MkdirAllAndChown(config.Root, 0701, id); err != nil { - return errors.Wrapf(err, "could not create or set daemon root permissions: %s", config.Root) - } - config.Root = filepath.Join(rootDir, fmt.Sprintf("%d.%d", remappedRoot.UID, remappedRoot.GID)) logrus.Debugf("Creating user namespaced daemon root: %s", config.Root) // Create the root directory if it doesn't exist - if err := idtools.MkdirAllAndChown(config.Root, 0701, id); err != nil { + if err := idtools.MkdirAllAndChown(config.Root, 0710, id); err != nil { return fmt.Errorf("Cannot create daemon root: %s: %v", config.Root, err) } // we also need to verify that any pre-existing directories in the path to diff --git a/daemon/graphdriver/aufs/aufs.go b/daemon/graphdriver/aufs/aufs.go index b007274e13..cfa18666d9 100644 --- a/daemon/graphdriver/aufs/aufs.go +++ b/daemon/graphdriver/aufs/aufs.go @@ -130,14 +130,23 @@ func Init(root string, options []string, uidMaps, gidMaps []idtools.IDMap) (grap } currentID := idtools.CurrentIdentity() + _, rootGID, err := idtools.GetRootUIDGID(uidMaps, gidMaps) + if err != nil { + return nil, err + } + dirID := idtools.Identity{ + UID: currentID.UID, + GID: rootGID, + } + // Create the root aufs driver dir - if err := idtools.MkdirAllAndChown(root, 0701, currentID); err != nil { + if err := idtools.MkdirAllAndChown(root, 0710, dirID); err != nil { return nil, err } // Populate the dir structure for _, p := range paths { - if err := idtools.MkdirAllAndChown(path.Join(root, p), 0701, currentID); err != nil { + if err := idtools.MkdirAllAndChown(path.Join(root, p), 0710, dirID); err != nil { return nil, err } } diff --git a/daemon/graphdriver/btrfs/btrfs.go b/daemon/graphdriver/btrfs/btrfs.go index 0499489d16..8fd2854a26 100644 --- a/daemon/graphdriver/btrfs/btrfs.go +++ b/daemon/graphdriver/btrfs/btrfs.go @@ -70,7 +70,14 @@ func Init(home string, options []string, uidMaps, gidMaps []idtools.IDMap) (grap return nil, graphdriver.ErrPrerequisites } - if err := idtools.MkdirAllAndChown(home, 0701, idtools.CurrentIdentity()); err != nil { + remappedRoot := idtools.NewIDMappingsFromMaps(uidMaps, gidMaps) + currentID := idtools.CurrentIdentity() + dirID := idtools.Identity{ + UID: currentID.UID, + GID: remappedRoot.RootPair().GID, + } + + if err := idtools.MkdirAllAndChown(home, 0710, dirID); err != nil { return nil, err } @@ -521,7 +528,14 @@ func (d *Driver) Create(id, parent string, opts *graphdriver.CreateOpts) error { if err != nil { return err } - if err := idtools.MkdirAllAndChown(subvolumes, 0701, idtools.CurrentIdentity()); err != nil { + + currentID := idtools.CurrentIdentity() + dirID := idtools.Identity{ + UID: currentID.UID, + GID: rootGID, + } + + if err := idtools.MkdirAllAndChown(subvolumes, 0710, dirID); err != nil { return err } if parent == "" { diff --git a/daemon/graphdriver/fuse-overlayfs/fuseoverlayfs.go b/daemon/graphdriver/fuse-overlayfs/fuseoverlayfs.go index 782e8be984..1bf30f4298 100644 --- a/daemon/graphdriver/fuse-overlayfs/fuseoverlayfs.go +++ b/daemon/graphdriver/fuse-overlayfs/fuseoverlayfs.go @@ -88,7 +88,17 @@ func Init(home string, options []string, uidMaps, gidMaps []idtools.IDMap) (grap return nil, graphdriver.ErrNotSupported } - if err := idtools.MkdirAllAndChown(path.Join(home, linkDir), 0701, idtools.CurrentIdentity()); err != nil { + remappedRoot := idtools.NewIDMappingsFromMaps(uidMaps, gidMaps) + currentID := idtools.CurrentIdentity() + dirID := idtools.Identity{ + UID: currentID.UID, + GID: remappedRoot.RootPair().GID, + } + + if err := idtools.MkdirAllAndChown(home, 0710, dirID); err != nil { + return nil, err + } + if err := idtools.MkdirAllAndChown(path.Join(home, linkDir), 700, currentID); err != nil { return nil, err } @@ -173,11 +183,15 @@ func (d *Driver) create(id, parent string, opts *graphdriver.CreateOpts) (retErr } root := idtools.Identity{UID: rootUID, GID: rootGID} - currentID := idtools.CurrentIdentity() - if err := idtools.MkdirAllAndChown(path.Dir(dir), 0701, currentID); err != nil { + dirID := idtools.Identity{ + UID: rootUID, + GID: rootGID, + } + + if err := idtools.MkdirAllAndChown(path.Dir(dir), 0710, dirID); err != nil { return err } - if err := idtools.MkdirAndChown(dir, 0701, currentID); err != nil { + if err := idtools.MkdirAndChown(dir, 0710, dirID); err != nil { return err } @@ -211,7 +225,7 @@ func (d *Driver) create(id, parent string, opts *graphdriver.CreateOpts) (retErr return nil } - if err := idtools.MkdirAndChown(path.Join(dir, workDirName), 0701, currentID); err != nil { + if err := idtools.MkdirAndChown(path.Join(dir, workDirName), 0710, dirID); err != nil { return err } diff --git a/daemon/graphdriver/overlay/overlay.go b/daemon/graphdriver/overlay/overlay.go index 90be0e3d64..6e9897da05 100644 --- a/daemon/graphdriver/overlay/overlay.go +++ b/daemon/graphdriver/overlay/overlay.go @@ -156,11 +156,20 @@ func Init(home string, options []string, uidMaps, gidMaps []idtools.IDMap) (grap logrus.WithField("storage-driver", "overlay").Warn(overlayutils.ErrDTypeNotSupported("overlay", backingFs)) } - // Create the driver home dir - if err := idtools.MkdirAllAndChown(home, 0701, idtools.CurrentIdentity()); err != nil { + currentID := idtools.CurrentIdentity() + _, rootGID, err := idtools.GetRootUIDGID(uidMaps, gidMaps) + if err != nil { return nil, err } + dirID := idtools.Identity{ + UID: currentID.UID, + GID: rootGID, + } + // Create the driver home dir + if err := idtools.MkdirAllAndChown(home, 0710, dirID); err != nil { + return nil, err + } d := &Driver{ home: home, uidMaps: uidMaps, @@ -262,10 +271,11 @@ func (d *Driver) Create(id, parent string, opts *graphdriver.CreateOpts) (retErr root := idtools.Identity{UID: rootUID, GID: rootGID} currentID := idtools.CurrentIdentity() - if err := idtools.MkdirAllAndChown(path.Dir(dir), 0701, currentID); err != nil { - return err + dirID := idtools.Identity{ + UID: currentID.UID, + GID: rootGID, } - if err := idtools.MkdirAndChown(dir, 0701, currentID); err != nil { + if err := idtools.MkdirAndChown(dir, 0710, dirID); err != nil { return err } diff --git a/daemon/graphdriver/overlay2/overlay.go b/daemon/graphdriver/overlay2/overlay.go index 36a921a018..562d1e58fd 100644 --- a/daemon/graphdriver/overlay2/overlay.go +++ b/daemon/graphdriver/overlay2/overlay.go @@ -165,7 +165,20 @@ func Init(home string, options []string, uidMaps, gidMaps []idtools.IDMap) (grap logger.Warn(overlayutils.ErrDTypeNotSupported("overlay2", backingFs)) } - if err := idtools.MkdirAllAndChown(path.Join(home, linkDir), 0701, idtools.CurrentIdentity()); err != nil { + _, rootGID, err := idtools.GetRootUIDGID(uidMaps, gidMaps) + if err != nil { + return nil, err + } + + cur := idtools.CurrentIdentity() + dirID := idtools.Identity{ + UID: cur.UID, + GID: rootGID, + } + if err := idtools.MkdirAllAndChown(home, 0710, dirID); err != nil { + return nil, err + } + if err := idtools.MkdirAllAndChown(path.Join(home, linkDir), 0700, cur); err != nil { return nil, err } @@ -344,12 +357,15 @@ func (d *Driver) create(id, parent string, opts *graphdriver.CreateOpts) (retErr return err } root := idtools.Identity{UID: rootUID, GID: rootGID} - current := idtools.CurrentIdentity() + dirID := idtools.Identity{ + UID: idtools.CurrentIdentity().UID, + GID: rootGID, + } - if err := idtools.MkdirAllAndChown(path.Dir(dir), 0701, current); err != nil { + if err := idtools.MkdirAllAndChown(path.Dir(dir), 0710, dirID); err != nil { return err } - if err := idtools.MkdirAndChown(dir, 0701, current); err != nil { + if err := idtools.MkdirAndChown(dir, 0710, dirID); err != nil { return err } diff --git a/daemon/graphdriver/vfs/driver.go b/daemon/graphdriver/vfs/driver.go index af9b107609..f903393da2 100644 --- a/daemon/graphdriver/vfs/driver.go +++ b/daemon/graphdriver/vfs/driver.go @@ -37,8 +37,16 @@ func Init(home string, options []string, uidMaps, gidMaps []idtools.IDMap) (grap if err := d.parseOptions(options); err != nil { return nil, err } + _, rootGID, err := idtools.GetRootUIDGID(uidMaps, gidMaps) + if err != nil { + return nil, err + } - if err := idtools.MkdirAllAndChown(home, 0701, idtools.CurrentIdentity()); err != nil { + dirID := idtools.Identity{ + UID: idtools.CurrentIdentity().UID, + GID: rootGID, + } + if err := idtools.MkdirAllAndChown(home, 0710, dirID); err != nil { return nil, err } @@ -140,7 +148,12 @@ func (d *Driver) Create(id, parent string, opts *graphdriver.CreateOpts) error { func (d *Driver) create(id, parent string, size uint64) error { dir := d.dir(id) rootIDs := d.idMapping.RootPair() - if err := idtools.MkdirAllAndChown(filepath.Dir(dir), 0701, idtools.CurrentIdentity()); err != nil { + + dirID := idtools.Identity{ + UID: idtools.CurrentIdentity().UID, + GID: rootIDs.GID, + } + if err := idtools.MkdirAllAndChown(filepath.Dir(dir), 0710, dirID); err != nil { return err } if err := idtools.MkdirAndChown(dir, 0755, rootIDs); err != nil { diff --git a/daemon/graphdriver/zfs/zfs.go b/daemon/graphdriver/zfs/zfs.go index f9099a2094..2fbbe9498f 100644 --- a/daemon/graphdriver/zfs/zfs.go +++ b/daemon/graphdriver/zfs/zfs.go @@ -104,7 +104,16 @@ func Init(base string, opt []string, uidMaps, gidMaps []idtools.IDMap) (graphdri return nil, fmt.Errorf("BUG: zfs get all -t filesystem -rHp '%s' should contain '%s'", options.fsName, options.fsName) } - if err := idtools.MkdirAllAndChown(base, 0701, idtools.CurrentIdentity()); err != nil { + _, rootGID, err := idtools.GetRootUIDGID(uidMaps, gidMaps) + if err != nil { + return nil, err + } + + dirID := idtools.Identity{ + UID: idtools.CurrentIdentity().UID, + GID: rootGID, + } + if err := idtools.MkdirAllAndChown(base, 0710, dirID); err != nil { return nil, fmt.Errorf("Failed to create '%s': %v", base, err) }