From f31ba2929ba64f5f279bb3d8d60562d4b77fd0df Mon Sep 17 00:00:00 2001 From: Giuseppe Scrivano Date: Sun, 10 Mar 2019 11:22:57 +0100 Subject: rootless: support a custom arg to the new process let the process running as euid != 0 pass down an argument to the process running in the user namespace. This will be useful for commands like rm -a that needs to join different namespaces, so that we can re-exec separately for each of them. Signed-off-by: Giuseppe Scrivano --- pkg/rootless/rootless_linux.go | 37 +++++++++++++++++++++++++++++++++++-- 1 file changed, 35 insertions(+), 2 deletions(-) (limited to 'pkg/rootless/rootless_linux.go') diff --git a/pkg/rootless/rootless_linux.go b/pkg/rootless/rootless_linux.go index 933cfa2c2..69614cefc 100644 --- a/pkg/rootless/rootless_linux.go +++ b/pkg/rootless/rootless_linux.go @@ -61,6 +61,11 @@ func SkipStorageSetup() bool { return skipStorageSetup } +// Argument returns the argument that was set for the rootless session. +func Argument() string { + return os.Getenv("_LIBPOD_ROOTLESS_ARG") +} + // GetRootlessUID returns the UID of the user in the parent userNS func GetRootlessUID() int { uidEnv := os.Getenv("_LIBPOD_ROOTLESS_UID") @@ -135,8 +140,16 @@ func JoinNS(pid uint, preserveFDs int) (bool, int, error) { // JoinDirectUserAndMountNS re-exec podman in a new userNS and join the user and mount // namespace of the specified PID without looking up its parent. Useful to join directly -// the conmon process. +// the conmon process. It is a convenience function for JoinDirectUserAndMountNSWithOpts +// with a default configuration. func JoinDirectUserAndMountNS(pid uint) (bool, int, error) { + return JoinDirectUserAndMountNSWithOpts(pid, nil) +} + +// JoinDirectUserAndMountNSWithOpts re-exec podman in a new userNS and join the user and +// mount namespace of the specified PID without looking up its parent. Useful to join +// directly the conmon process. +func JoinDirectUserAndMountNSWithOpts(pid uint, opts *Opts) (bool, int, error) { if os.Geteuid() == 0 || os.Getenv("_LIBPOD_USERNS_CONFIGURED") != "" { return false, -1, nil } @@ -153,6 +166,12 @@ func JoinDirectUserAndMountNS(pid uint) (bool, int, error) { } defer userNS.Close() + if opts != nil && opts.Argument != "" { + if err := os.Setenv("_LIBPOD_ROOTLESS_ARG", opts.Argument); err != nil { + return false, -1, err + } + } + pidC := C.reexec_userns_join(C.int(userNS.Fd()), C.int(mountNS.Fd())) if int(pidC) < 0 { return false, -1, errors.Errorf("cannot re-exec process") @@ -211,8 +230,16 @@ func getMinimumIDs(p string) int { // BecomeRootInUserNS re-exec podman in a new userNS. It returns whether podman was re-executed // into a new user namespace and the return code from the re-executed podman process. // If podman was re-executed the caller needs to propagate the error code returned by the child -// process. +// process. It is a convenience function for BecomeRootInUserNSWithOpts with a default configuration. func BecomeRootInUserNS() (bool, int, error) { + return BecomeRootInUserNSWithOpts(nil) +} + +// BecomeRootInUserNSWithOpts re-exec podman in a new userNS. It returns whether podman was +// re-execute into a new user namespace and the return code from the re-executed podman process. +// If podman was re-executed the caller needs to propagate the error code returned by the child +// process. +func BecomeRootInUserNSWithOpts(opts *Opts) (bool, int, error) { if os.Geteuid() == 0 || os.Getenv("_LIBPOD_USERNS_CONFIGURED") != "" { if os.Getenv("_LIBPOD_USERNS_CONFIGURED") == "init" { return false, 0, runInUser() @@ -231,6 +258,12 @@ func BecomeRootInUserNS() (bool, int, error) { defer w.Close() defer w.Write([]byte("0")) + if opts != nil && opts.Argument != "" { + if err := os.Setenv("_LIBPOD_ROOTLESS_ARG", opts.Argument); err != nil { + return false, -1, err + } + } + pidC := C.reexec_in_user_namespace(C.int(r.Fd())) pid := int(pidC) if pid < 0 { -- cgit v1.2.3-54-g00ecf