From c5753f57c1a929f80fb768ff62bd35f383584aed Mon Sep 17 00:00:00 2001 From: Giuseppe Scrivano Date: Fri, 24 Aug 2018 12:15:34 +0200 Subject: rootless: exec handle processes that create an user namespace Manage the case where the main process of the container creates and joins a new user namespace. In this case we want to join only the first child in the new hierarchy, which is the user namespace that was used to create the container. Signed-off-by: Giuseppe Scrivano Closes: #1331 Approved by: rhatdan --- libpod/container_api.go | 6 +----- libpod/oci.go | 14 +++++++++++--- 2 files changed, 12 insertions(+), 8 deletions(-) (limited to 'libpod') diff --git a/libpod/container_api.go b/libpod/container_api.go index 56947eb3a..5df7e2f0e 100644 --- a/libpod/container_api.go +++ b/libpod/container_api.go @@ -335,11 +335,7 @@ func (c *Container) Exec(tty, privileged bool, env, cmd []string, user string) e execCmd, err := c.runtime.ociRuntime.execContainer(c, cmd, capList, env, tty, hostUser, sessionID) if err != nil { - return errors.Wrapf(err, "error creating exec command for container %s", c.ID()) - } - - if err := execCmd.Start(); err != nil { - return errors.Wrapf(err, "error starting exec command for container %s", c.ID()) + return errors.Wrapf(err, "error exec %s", c.ID()) } pidFile := c.execPidPath(sessionID) diff --git a/libpod/oci.go b/libpod/oci.go index da054eceb..4f0fbe8e9 100644 --- a/libpod/oci.go +++ b/libpod/oci.go @@ -682,15 +682,23 @@ func (r *OCIRuntime) execContainer(c *Container, cmd, capAdd, env []string, tty execCmd := exec.Command(r.path, args...) if rootless.IsRootless() { - args = append([]string{"--preserve-credentials", "-U", "-t", fmt.Sprintf("%d", c.state.PID), r.path}, args...) - // using nsenter might not be correct if the target PID joined a different user namespace. - // A better way would be to retrieve the parent ns (NS_GET_PARENT) until it is a child of the current namespace. + args = append([]string{"--preserve-credentials", "--user=/proc/self/fd/3", r.path}, args...) + f, err := rootless.GetUserNSForPid(uint(c.state.PID)) + if err != nil { + return nil, err + } execCmd = exec.Command("nsenter", args...) + execCmd.ExtraFiles = append(execCmd.ExtraFiles, f) } execCmd.Stdout = os.Stdout execCmd.Stderr = os.Stderr execCmd.Stdin = os.Stdin execCmd.Env = append(execCmd.Env, fmt.Sprintf("XDG_RUNTIME_DIR=%s", runtimeDir)) + + if err := execCmd.Start(); err != nil { + return nil, errors.Wrapf(err, "cannot start container %s", c.ID()) + } + return execCmd, nil } -- cgit v1.2.3-54-g00ecf