From bfedd2725971303efb7a2fe5d6990317b381622f Mon Sep 17 00:00:00 2001 From: Brian Goff Date: Tue, 6 Oct 2020 19:40:30 +0000 Subject: Do not set DOCKER_TMP to be owned by remapped root The remapped root does not need access to this dir. Having this owned by the remapped root opens the host up to an uprivileged user on the host being able to escalate privileges. While it would not be normal for the remapped UID to be used outside of the container context, it could happen. Signed-off-by: Brian Goff --- daemon/daemon.go | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) diff --git a/daemon/daemon.go b/daemon/daemon.go index 3e86ab5c87..ab0db4fa06 100644 --- a/daemon/daemon.go +++ b/daemon/daemon.go @@ -795,7 +795,7 @@ func NewDaemon(ctx context.Context, config *config.Config, pluginStore *plugin.S } // set up the tmpDir to use a canonical path - tmp, err := prepareTempDir(config.Root, rootIDs) + tmp, err := prepareTempDir(config.Root) if err != nil { return nil, fmt.Errorf("Unable to get the TempDir under %s: %s", config.Root, err) } @@ -1370,7 +1370,7 @@ func (daemon *Daemon) Subnets() ([]net.IPNet, []net.IPNet) { // prepareTempDir prepares and returns the default directory to use // for temporary files. // If it doesn't exist, it is created. If it exists, its content is removed. -func prepareTempDir(rootDir string, rootIdentity idtools.Identity) (string, error) { +func prepareTempDir(rootDir string) (string, error) { var tmpDir string if tmpDir = os.Getenv("DOCKER_TMPDIR"); tmpDir == "" { tmpDir = filepath.Join(rootDir, "tmp") @@ -1388,9 +1388,7 @@ func prepareTempDir(rootDir string, rootIdentity idtools.Identity) (string, erro } } } - // We don't remove the content of tmpdir if it's not the default, - // it may hold things that do not belong to us. - return tmpDir, idtools.MkdirAllAndChown(tmpDir, 0700, rootIdentity) + return tmpDir, idtools.MkdirAllAndChown(tmpDir, 0700, idtools.CurrentIdentity()) } func (daemon *Daemon) setGenericResources(conf *config.Config) error { -- cgit v1.2.1