Bump github.com/containers/common from 0.6.1 to 0.8.0

Bumps [github.com/containers/common](https://github.com/containers/common) from 0.6.1 to 0.8.0.
- [Release notes](https://github.com/containers/common/releases)
- [Commits](https://github.com/containers/common/compare/v0.6.1...v0.8.0)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>
Signed-off-by: Daniel J Walsh <dwalsh@redhat.com>

vendor/github.com/containers/storage/pkg/config/config.go

@@ -134,6 +134,18 @@ type OptionsConfig struct {
 	// should be used to set up default GID mappings.
 	RemapGroup string `toml:"remap-group"`
 
+	// RootAutoUsernsUser is the name of one or more entries in /etc/subuid and
+	// /etc/subgid which should be used to set up automatically a userns.
+	RootAutoUsernsUser string `toml:"root-auto-userns-user"`
+
+	// AutoUsernsMinSize is the minimum size for a user namespace that is
+	// created automatically.
+	AutoUsernsMinSize uint32 `toml:"auto-userns-min-size"`
+
+	// AutoUsernsMaxSize is the maximum size for a user namespace that is
+	// created automatically.
+	AutoUsernsMaxSize uint32 `toml:"auto-userns-max-size"`
+
 	// Aufs container options to be handed to aufs drivers
 	Aufs struct{ AufsOptionsConfig } `toml:"aufs"`
 

vendor/github.com/containers/storage/pkg/unshare/getenv_linux_cgo.go

@@ -0,0 +1,22 @@
+// +build linux,cgo
+
+package unshare
+
+import (
+	"unsafe"
+)
+
+/*
+#cgo remoteclient CFLAGS: -Wall -Werror
+#include <stdlib.h>
+*/
+import "C"
+
+func getenv(name string) string {
+	cName := C.CString(name)
+	defer C.free(unsafe.Pointer(cName))
+
+	value := C.GoString(C.getenv(cName))
+
+	return value
+}

vendor/github.com/containers/storage/pkg/unshare/getenv_linux_nocgo.go

@@ -0,0 +1,11 @@
+// +build linux,!cgo
+
+package unshare
+
+import (
+	"os"
+)
+
+func getenv(name string) string {
+	return os.Getenv(name)
+}

vendor/github.com/containers/storage/pkg/unshare/unshare.c

@@ -0,0 +1,291 @@
+#ifndef UNSHARE_NO_CODE_AT_ALL
+
+#define _GNU_SOURCE
+#include <sys/types.h>
+#include <sys/ioctl.h>
+#include <sys/stat.h>
+#include <sys/syscall.h>
+#include <sys/mman.h>
+#include <fcntl.h>
+#include <grp.h>
+#include <sched.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <termios.h>
+#include <errno.h>
+#include <unistd.h>
+
+/* Open Source projects like conda-forge, want to package podman and are based
+   off of centos:6, Conda-force has minimal libc requirements and is lacking
+   the memfd.h file, so we use mmam.h
+*/
+#ifndef MFD_ALLOW_SEALING
+#define MFD_ALLOW_SEALING 2U
+#endif
+#ifndef MFD_CLOEXEC
+#define MFD_CLOEXEC 1U
+#endif
+
+#ifndef F_LINUX_SPECIFIC_BASE
+#define F_LINUX_SPECIFIC_BASE 1024
+#endif
+#ifndef F_ADD_SEALS
+#define F_ADD_SEALS (F_LINUX_SPECIFIC_BASE + 9)
+#define F_GET_SEALS (F_LINUX_SPECIFIC_BASE + 10)
+#endif
+#ifndef F_SEAL_SEAL
+#define F_SEAL_SEAL   0x0001LU
+#endif
+#ifndef F_SEAL_SHRINK
+#define F_SEAL_SHRINK 0x0002LU
+#endif
+#ifndef F_SEAL_GROW
+#define F_SEAL_GROW   0x0004LU
+#endif
+#ifndef F_SEAL_WRITE
+#define F_SEAL_WRITE  0x0008LU
+#endif
+
+#define BUFSTEP 1024
+
+static const char *_max_user_namespaces = "/proc/sys/user/max_user_namespaces";
+static const char *_unprivileged_user_namespaces = "/proc/sys/kernel/unprivileged_userns_clone";
+
+static int _containers_unshare_parse_envint(const char *envname) {
+	char *p, *q;
+	long l;
+
+	p = getenv(envname);
+	if (p == NULL) {
+		return -1;
+	}
+	q = NULL;
+	l = strtol(p, &q, 10);
+	if ((q == NULL) || (*q != '\0')) {
+		fprintf(stderr, "Error parsing \"%s\"=\"%s\"!\n", envname, p);
+		_exit(1);
+	}
+	unsetenv(envname);
+	return l;
+}
+
+static void _check_proc_sys_file(const char *path)
+{
+	FILE *fp;
+	char buf[32];
+	size_t n_read;
+	long r;
+
+	fp = fopen(path, "r");
+	if (fp == NULL) {
+		if (errno != ENOENT)
+			fprintf(stderr, "Error reading %s: %m\n", _max_user_namespaces);
+	} else {
+		memset(buf, 0, sizeof(buf));
+		n_read = fread(buf, 1, sizeof(buf) - 1, fp);
+		if (n_read > 0) {
+			r = atoi(buf);
+			if (r == 0) {
+				fprintf(stderr, "User namespaces are not enabled in %s.\n", path);
+			}
+		} else {
+			fprintf(stderr, "Error reading %s: no contents, should contain a number greater than 0.\n", path);
+		}
+		fclose(fp);
+	}
+}
+
+static char **parse_proc_stringlist(const char *list) {
+	int fd, n, i, n_strings;
+	char *buf, *new_buf, **ret;
+	size_t size, new_size, used;
+
+	fd = open(list, O_RDONLY);
+	if (fd == -1) {
+		return NULL;
+	}
+	buf = NULL;
+	size = 0;
+	used = 0;
+	for (;;) {
+		new_size = used + BUFSTEP;
+		new_buf = realloc(buf, new_size);
+		if (new_buf == NULL) {
+			free(buf);
+			fprintf(stderr, "realloc(%ld): out of memory\n", (long)(size + BUFSTEP));
+			return NULL;
+		}
+		buf = new_buf;
+		size = new_size;
+		memset(buf + used, '\0', size - used);
+		n = read(fd, buf + used, size - used - 1);
+		if (n < 0) {
+			fprintf(stderr, "read(): %m\n");
+			return NULL;
+		}
+		if (n == 0) {
+			break;
+		}
+		used += n;
+	}
+	close(fd);
+	n_strings = 0;
+	for (n = 0; n < used; n++) {
+		if ((n == 0) || (buf[n-1] == '\0')) {
+			n_strings++;
+		}
+	}
+	ret = calloc(n_strings + 1, sizeof(char *));
+	if (ret == NULL) {
+		fprintf(stderr, "calloc(): out of memory\n");
+		return NULL;
+	}
+	i = 0;
+	for (n = 0; n < used; n++) {
+		if ((n == 0) || (buf[n-1] == '\0')) {
+			ret[i++] = &buf[n];
+		}
+	}
+	ret[i] = NULL;
+	return ret;
+}
+
+static int containers_reexec(void) {
+	char **argv, *exename;
+	int fd, mmfd, n_read, n_written;
+	struct stat st;
+	char buf[2048];
+
+	argv = parse_proc_stringlist("/proc/self/cmdline");
+	if (argv == NULL) {
+		return -1;
+	}
+	fd = open("/proc/self/exe", O_RDONLY | O_CLOEXEC);
+	if (fd == -1) {
+		fprintf(stderr, "open(\"/proc/self/exe\"): %m\n");
+		return -1;
+	}
+	if (fstat(fd, &st) == -1) {
+		fprintf(stderr, "fstat(\"/proc/self/exe\"): %m\n");
+		return -1;
+	}
+	exename = basename(argv[0]);
+	mmfd = syscall(SYS_memfd_create, exename, (long) MFD_ALLOW_SEALING | MFD_CLOEXEC);
+	if (mmfd == -1) {
+		fprintf(stderr, "memfd_create(): %m\n");
+		return -1;
+	}
+	for (;;) {
+		n_read = read(fd, buf, sizeof(buf));
+		if (n_read < 0) {
+			fprintf(stderr, "read(\"/proc/self/exe\"): %m\n");
+			return -1;
+		}
+		if (n_read == 0) {
+			break;
+		}
+		n_written = write(mmfd, buf, n_read);
+		if (n_written < 0) {
+			fprintf(stderr, "write(anonfd): %m\n");
+			return -1;
+		}
+		if (n_written != n_read) {
+			fprintf(stderr, "write(anonfd): short write (%d != %d)\n", n_written, n_read);
+			return -1;
+		}
+	}
+	close(fd);
+	if (fcntl(mmfd, F_ADD_SEALS, F_SEAL_SHRINK | F_SEAL_GROW | F_SEAL_WRITE | F_SEAL_SEAL) == -1) {
+		close(mmfd);
+		fprintf(stderr, "Error sealing memfd copy: %m\n");
+		return -1;
+	}
+	if (fexecve(mmfd, argv, environ) == -1) {
+		close(mmfd);
+		fprintf(stderr, "Error during reexec(...): %m\n");
+		return -1;
+	}
+	return 0;
+}
+
+void _containers_unshare(void)
+{
+	int flags, pidfd, continuefd, n, pgrp, sid, ctty;
+	char buf[2048];
+
+	flags = _containers_unshare_parse_envint("_Containers-unshare");
+	if (flags == -1) {
+		return;
+	}
+	if ((flags & CLONE_NEWUSER) != 0) {
+		if (unshare(CLONE_NEWUSER) == -1) {
+			fprintf(stderr, "Error during unshare(CLONE_NEWUSER): %m\n");
+                        _check_proc_sys_file (_max_user_namespaces);
+                        _check_proc_sys_file (_unprivileged_user_namespaces);
+			_exit(1);
+		}
+	}
+	pidfd = _containers_unshare_parse_envint("_Containers-pid-pipe");
+	if (pidfd != -1) {
+		snprintf(buf, sizeof(buf), "%llu", (unsigned long long) getpid());
+		size_t size = write(pidfd, buf, strlen(buf));
+		if (size != strlen(buf)) {
+			fprintf(stderr, "Error writing PID to pipe on fd %d: %m\n", pidfd);
+			_exit(1);
+		}
+		close(pidfd);
+	}
+	continuefd = _containers_unshare_parse_envint("_Containers-continue-pipe");
+	if (continuefd != -1) {
+		n = read(continuefd, buf, sizeof(buf));
+		if (n > 0) {
+			fprintf(stderr, "Error: %.*s\n", n, buf);
+			_exit(1);
+		}
+		close(continuefd);
+	}
+	sid = _containers_unshare_parse_envint("_Containers-setsid");
+	if (sid == 1) {
+		if (setsid() == -1) {
+			fprintf(stderr, "Error during setsid: %m\n");
+			_exit(1);
+		}
+	}
+	pgrp = _containers_unshare_parse_envint("_Containers-setpgrp");
+	if (pgrp == 1) {
+		if (setpgrp() == -1) {
+			fprintf(stderr, "Error during setpgrp: %m\n");
+			_exit(1);
+		}
+	}
+	ctty = _containers_unshare_parse_envint("_Containers-ctty");
+	if (ctty != -1) {
+		if (ioctl(ctty, TIOCSCTTY, 0) == -1) {
+			fprintf(stderr, "Error while setting controlling terminal to %d: %m\n", ctty);
+			_exit(1);
+		}
+	}
+	if ((flags & CLONE_NEWUSER) != 0) {
+		if (setresgid(0, 0, 0) != 0) {
+			fprintf(stderr, "Error during setresgid(0): %m\n");
+			_exit(1);
+		}
+		if (setresuid(0, 0, 0) != 0) {
+			fprintf(stderr, "Error during setresuid(0): %m\n");
+			_exit(1);
+		}
+	}
+	if ((flags & ~CLONE_NEWUSER) != 0) {
+		if (unshare(flags & ~CLONE_NEWUSER) == -1) {
+			fprintf(stderr, "Error during unshare(...): %m\n");
+			_exit(1);
+		}
+	}
+	if (containers_reexec() != 0) {
+		_exit(1);
+	}
+	return;
+}
+
+#endif // !UNSHARE_NO_CODE_AT_ALL

vendor/github.com/containers/storage/pkg/unshare/unshare.go

@@ -0,0 +1,22 @@
+package unshare
+
+import (
+	"fmt"
+	"os"
+	"os/user"
+
+	"github.com/pkg/errors"
+)
+
+// HomeDir returns the home directory for the current user.
+func HomeDir() (string, error) {
+	home := os.Getenv("HOME")
+	if home == "" {
+		usr, err := user.LookupId(fmt.Sprintf("%d", GetRootlessUID()))
+		if err != nil {
+			return "", errors.Wrapf(err, "unable to resolve HOME directory")
+		}
+		home = usr.HomeDir
+	}
+	return home, nil
+}

vendor/github.com/containers/storage/pkg/unshare/unshare_cgo.go

@@ -0,0 +1,10 @@
+// +build linux,cgo,!gccgo
+
+package unshare
+
+// #cgo CFLAGS: -Wall
+// extern void _containers_unshare(void);
+// void __attribute__((constructor)) init(void) {
+//   _containers_unshare();
+// }
+import "C"

vendor/github.com/containers/storage/pkg/unshare/unshare_gccgo.go

@@ -0,0 +1,25 @@
+// +build linux,cgo,gccgo
+
+package unshare
+
+// #cgo CFLAGS: -Wall -Wextra
+// extern void _containers_unshare(void);
+// void __attribute__((constructor)) init(void) {
+//   _containers_unshare();
+// }
+import "C"
+
+// This next bit is straight out of libcontainer.
+
+// AlwaysFalse is here to stay false
+// (and be exported so the compiler doesn't optimize out its reference)
+var AlwaysFalse bool
+
+func init() {
+	if AlwaysFalse {
+		// by referencing this C init() in a noop test, it will ensure the compiler
+		// links in the C function.
+		// https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65134
+		C.init()
+	}
+}

vendor/github.com/containers/storage/pkg/unshare/unshare_linux.go

@@ -0,0 +1,605 @@
+// +build linux
+
+package unshare
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"io"
+	"os"
+	"os/exec"
+	"os/user"
+	"runtime"
+	"strconv"
+	"strings"
+	"sync"
+	"syscall"
+
+	"github.com/containers/storage/pkg/idtools"
+	"github.com/containers/storage/pkg/reexec"
+	"github.com/opencontainers/runtime-spec/specs-go"
+	"github.com/pkg/errors"
+	"github.com/sirupsen/logrus"
+	"github.com/syndtr/gocapability/capability"
+)
+
+// Cmd wraps an exec.Cmd created by the reexec package in unshare(), and
+// handles setting ID maps and other related settings by triggering
+// initialization code in the child.
+type Cmd struct {
+	*exec.Cmd
+	UnshareFlags               int
+	UseNewuidmap               bool
+	UidMappings                []specs.LinuxIDMapping // nolint: golint
+	UseNewgidmap               bool
+	GidMappings                []specs.LinuxIDMapping // nolint: golint
+	GidMappingsEnableSetgroups bool
+	Setsid                     bool
+	Setpgrp                    bool
+	Ctty                       *os.File
+	OOMScoreAdj                *int
+	Hook                       func(pid int) error
+}
+
+// Command creates a new Cmd which can be customized.
+func Command(args ...string) *Cmd {
+	cmd := reexec.Command(args...)
+	return &Cmd{
+		Cmd: cmd,
+	}
+}
+
+func getRootlessUID() int {
+	uidEnv := getenv("_CONTAINERS_ROOTLESS_UID")
+	if uidEnv != "" {
+		u, _ := strconv.Atoi(uidEnv)
+		return u
+	}
+	return os.Geteuid()
+}
+
+func getRootlessGID() int {
+	gidEnv := getenv("_CONTAINERS_ROOTLESS_GID")
+	if gidEnv != "" {
+		u, _ := strconv.Atoi(gidEnv)
+		return u
+	}
+
+	/* If the _CONTAINERS_ROOTLESS_UID is set, assume the gid==uid.  */
+	uidEnv := os.Getenv("_CONTAINERS_ROOTLESS_UID")
+	if uidEnv != "" {
+		u, _ := strconv.Atoi(uidEnv)
+		return u
+	}
+	return os.Getegid()
+}
+
+func (c *Cmd) Start() error {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	// Set an environment variable to tell the child to synchronize its startup.
+	if c.Env == nil {
+		c.Env = os.Environ()
+	}
+	c.Env = append(c.Env, fmt.Sprintf("_Containers-unshare=%d", c.UnshareFlags))
+
+	// Please the libpod "rootless" package to find the expected env variables.
+	if IsRootless() {
+		c.Env = append(c.Env, "_CONTAINERS_USERNS_CONFIGURED=done")
+		c.Env = append(c.Env, fmt.Sprintf("_CONTAINERS_ROOTLESS_UID=%d", getRootlessUID()))
+		c.Env = append(c.Env, fmt.Sprintf("_CONTAINERS_ROOTLESS_GID=%d", getRootlessGID()))
+	}
+
+	// Create the pipe for reading the child's PID.
+	pidRead, pidWrite, err := os.Pipe()
+	if err != nil {
+		return errors.Wrapf(err, "error creating pid pipe")
+	}
+	c.Env = append(c.Env, fmt.Sprintf("_Containers-pid-pipe=%d", len(c.ExtraFiles)+3))
+	c.ExtraFiles = append(c.ExtraFiles, pidWrite)
+
+	// Create the pipe for letting the child know to proceed.
+	continueRead, continueWrite, err := os.Pipe()
+	if err != nil {
+		pidRead.Close()
+		pidWrite.Close()
+		return errors.Wrapf(err, "error creating pid pipe")
+	}
+	c.Env = append(c.Env, fmt.Sprintf("_Containers-continue-pipe=%d", len(c.ExtraFiles)+3))
+	c.ExtraFiles = append(c.ExtraFiles, continueRead)
+
+	// Pass along other instructions.
+	if c.Setsid {
+		c.Env = append(c.Env, "_Containers-setsid=1")
+	}
+	if c.Setpgrp {
+		c.Env = append(c.Env, "_Containers-setpgrp=1")
+	}
+	if c.Ctty != nil {
+		c.Env = append(c.Env, fmt.Sprintf("_Containers-ctty=%d", len(c.ExtraFiles)+3))
+		c.ExtraFiles = append(c.ExtraFiles, c.Ctty)
+	}
+
+	// Make sure we clean up our pipes.
+	defer func() {
+		if pidRead != nil {
+			pidRead.Close()
+		}
+		if pidWrite != nil {
+			pidWrite.Close()
+		}
+		if continueRead != nil {
+			continueRead.Close()
+		}
+		if continueWrite != nil {
+			continueWrite.Close()
+		}
+	}()
+
+	// Start the new process.
+	err = c.Cmd.Start()
+	if err != nil {
+		return err
+	}
+
+	// Close the ends of the pipes that the parent doesn't need.
+	continueRead.Close()
+	continueRead = nil
+	pidWrite.Close()
+	pidWrite = nil
+
+	// Read the child's PID from the pipe.
+	pidString := ""
+	b := new(bytes.Buffer)
+	if _, err := io.Copy(b, pidRead); err != nil {
+		return errors.Wrapf(err, "error reading child PID")
+	}
+	pidString = b.String()
+	pid, err := strconv.Atoi(pidString)
+	if err != nil {
+		fmt.Fprintf(continueWrite, "error parsing PID %q: %v", pidString, err)
+		return errors.Wrapf(err, "error parsing PID %q", pidString)
+	}
+	pidString = fmt.Sprintf("%d", pid)
+
+	// If we created a new user namespace, set any specified mappings.
+	if c.UnshareFlags&syscall.CLONE_NEWUSER != 0 {
+		// Always set "setgroups".
+		setgroups, err := os.OpenFile(fmt.Sprintf("/proc/%s/setgroups", pidString), os.O_TRUNC|os.O_WRONLY, 0)
+		if err != nil {
+			fmt.Fprintf(continueWrite, "error opening setgroups: %v", err)
+			return errors.Wrapf(err, "error opening /proc/%s/setgroups", pidString)
+		}
+		defer setgroups.Close()
+		if c.GidMappingsEnableSetgroups {
+			if _, err := fmt.Fprintf(setgroups, "allow"); err != nil {
+				fmt.Fprintf(continueWrite, "error writing \"allow\" to setgroups: %v", err)
+				return errors.Wrapf(err, "error opening \"allow\" to /proc/%s/setgroups", pidString)
+			}
+		} else {
+			if _, err := fmt.Fprintf(setgroups, "deny"); err != nil {
+				fmt.Fprintf(continueWrite, "error writing \"deny\" to setgroups: %v", err)
+				return errors.Wrapf(err, "error writing \"deny\" to /proc/%s/setgroups", pidString)
+			}
+		}
+
+		if len(c.UidMappings) == 0 || len(c.GidMappings) == 0 {
+			uidmap, gidmap, err := GetHostIDMappings("")
+			if err != nil {
+				fmt.Fprintf(continueWrite, "error reading ID mappings in parent: %v", err)
+				return errors.Wrapf(err, "error reading ID mappings in parent")
+			}
+			if len(c.UidMappings) == 0 {
+				c.UidMappings = uidmap
+				for i := range c.UidMappings {
+					c.UidMappings[i].HostID = c.UidMappings[i].ContainerID
+				}
+			}
+			if len(c.GidMappings) == 0 {
+				c.GidMappings = gidmap
+				for i := range c.GidMappings {
+					c.GidMappings[i].HostID = c.GidMappings[i].ContainerID
+				}
+			}
+		}
+
+		if len(c.GidMappings) > 0 {
+			// Build the GID map, since writing to the proc file has to be done all at once.
+			g := new(bytes.Buffer)
+			for _, m := range c.GidMappings {
+				fmt.Fprintf(g, "%d %d %d\n", m.ContainerID, m.HostID, m.Size)
+			}
+			gidmapSet := false
+			// Set the GID map.
+			if c.UseNewgidmap {
+				cmd := exec.Command("newgidmap", append([]string{pidString}, strings.Fields(strings.Replace(g.String(), "\n", " ", -1))...)...)
+				g.Reset()
+				cmd.Stdout = g
+				cmd.Stderr = g
+				err := cmd.Run()
+				if err == nil {
+					gidmapSet = true
+				} else {
+					logrus.Warnf("error running newgidmap: %v: %s", err, g.String())
+					logrus.Warnf("falling back to single mapping")
+					g.Reset()
+					g.Write([]byte(fmt.Sprintf("0 %d 1\n", os.Getegid())))
+				}
+			}
+			if !gidmapSet {
+				if c.UseNewgidmap {
+					setgroups, err := os.OpenFile(fmt.Sprintf("/proc/%s/setgroups", pidString), os.O_TRUNC|os.O_WRONLY, 0)
+					if err != nil {
+						fmt.Fprintf(continueWrite, "error opening /proc/%s/setgroups: %v", pidString, err)
+						return errors.Wrapf(err, "error opening /proc/%s/setgroups", pidString)
+					}
+					defer setgroups.Close()
+					if _, err := fmt.Fprintf(setgroups, "deny"); err != nil {
+						fmt.Fprintf(continueWrite, "error writing 'deny' to /proc/%s/setgroups: %v", pidString, err)
+						return errors.Wrapf(err, "error writing 'deny' to /proc/%s/setgroups", pidString)
+					}
+				}
+				gidmap, err := os.OpenFile(fmt.Sprintf("/proc/%s/gid_map", pidString), os.O_TRUNC|os.O_WRONLY, 0)
+				if err != nil {
+					fmt.Fprintf(continueWrite, "error opening /proc/%s/gid_map: %v", pidString, err)
+					return errors.Wrapf(err, "error opening /proc/%s/gid_map", pidString)
+				}
+				defer gidmap.Close()
+				if _, err := fmt.Fprintf(gidmap, "%s", g.String()); err != nil {
+					fmt.Fprintf(continueWrite, "error writing %q to /proc/%s/gid_map: %v", g.String(), pidString, err)
+					return errors.Wrapf(err, "error writing %q to /proc/%s/gid_map", g.String(), pidString)
+				}
+			}
+		}
+
+		if len(c.UidMappings) > 0 {
+			// Build the UID map, since writing to the proc file has to be done all at once.
+			u := new(bytes.Buffer)
+			for _, m := range c.UidMappings {
+				fmt.Fprintf(u, "%d %d %d\n", m.ContainerID, m.HostID, m.Size)
+			}
+			uidmapSet := false
+			// Set the GID map.
+			if c.UseNewuidmap {
+				cmd := exec.Command("newuidmap", append([]string{pidString}, strings.Fields(strings.Replace(u.String(), "\n", " ", -1))...)...)
+				u.Reset()
+				cmd.Stdout = u
+				cmd.Stderr = u
+				err := cmd.Run()
+				if err == nil {
+					uidmapSet = true
+				} else {
+					logrus.Warnf("error running newuidmap: %v: %s", err, u.String())
+					logrus.Warnf("falling back to single mapping")
+					u.Reset()
+					u.Write([]byte(fmt.Sprintf("0 %d 1\n", os.Geteuid())))
+				}
+			}
+			if !uidmapSet {
+				uidmap, err := os.OpenFile(fmt.Sprintf("/proc/%s/uid_map", pidString), os.O_TRUNC|os.O_WRONLY, 0)
+				if err != nil {
+					fmt.Fprintf(continueWrite, "error opening /proc/%s/uid_map: %v", pidString, err)
+					return errors.Wrapf(err, "error opening /proc/%s/uid_map", pidString)
+				}
+				defer uidmap.Close()
+				if _, err := fmt.Fprintf(uidmap, "%s", u.String()); err != nil {
+					fmt.Fprintf(continueWrite, "error writing %q to /proc/%s/uid_map: %v", u.String(), pidString, err)
+					return errors.Wrapf(err, "error writing %q to /proc/%s/uid_map", u.String(), pidString)
+				}
+			}
+		}
+	}
+
+	if c.OOMScoreAdj != nil {
+		oomScoreAdj, err := os.OpenFile(fmt.Sprintf("/proc/%s/oom_score_adj", pidString), os.O_TRUNC|os.O_WRONLY, 0)
+		if err != nil {
+			fmt.Fprintf(continueWrite, "error opening oom_score_adj: %v", err)
+			return errors.Wrapf(err, "error opening /proc/%s/oom_score_adj", pidString)
+		}
+		defer oomScoreAdj.Close()
+		if _, err := fmt.Fprintf(oomScoreAdj, "%d\n", *c.OOMScoreAdj); err != nil {
+			fmt.Fprintf(continueWrite, "error writing \"%d\" to oom_score_adj: %v", c.OOMScoreAdj, err)
+			return errors.Wrapf(err, "error writing \"%d\" to /proc/%s/oom_score_adj", c.OOMScoreAdj, pidString)
+		}
+	}
+	// Run any additional setup that we want to do before the child starts running proper.
+	if c.Hook != nil {
+		if err = c.Hook(pid); err != nil {
+			fmt.Fprintf(continueWrite, "hook error: %v", err)
+			return err
+		}
+	}
+
+	return nil
+}
+
+func (c *Cmd) Run() error {
+	if err := c.Start(); err != nil {
+		return err
+	}
+	return c.Wait()
+}
+
+func (c *Cmd) CombinedOutput() ([]byte, error) {
+	return nil, errors.New("unshare: CombinedOutput() not implemented")
+}
+
+func (c *Cmd) Output() ([]byte, error) {
+	return nil, errors.New("unshare: Output() not implemented")
+}
+
+var (
+	isRootlessOnce sync.Once
+	isRootless     bool
+)
+
+const (
+	// UsernsEnvName is the environment variable, if set indicates in rootless mode
+	UsernsEnvName = "_CONTAINERS_USERNS_CONFIGURED"
+)
+
+// IsRootless tells us if we are running in rootless mode
+func IsRootless() bool {
+	isRootlessOnce.Do(func() {
+		isRootless = getRootlessUID() != 0 || getenv(UsernsEnvName) != ""
+	})
+	return isRootless
+}
+
+// GetRootlessUID returns the UID of the user in the parent userNS
+func GetRootlessUID() int {
+	uidEnv := getenv("_CONTAINERS_ROOTLESS_UID")
+	if uidEnv != "" {
+		u, _ := strconv.Atoi(uidEnv)
+		return u
+	}
+	return os.Getuid()
+}
+
+// RootlessEnv returns the environment settings for the rootless containers
+func RootlessEnv() []string {
+	return append(os.Environ(), UsernsEnvName+"=done")
+}
+
+type Runnable interface {
+	Run() error
+}
+
+func bailOnError(err error, format string, a ...interface{}) { // nolint: golint,goprintffuncname
+	if err != nil {
+		if format != "" {
+			logrus.Errorf("%s: %v", fmt.Sprintf(format, a...), err)
+		} else {
+			logrus.Errorf("%v", err)
+		}
+		os.Exit(1)
+	}
+}
+
+// MaybeReexecUsingUserNamespace re-exec the process in a new namespace
+func MaybeReexecUsingUserNamespace(evenForRoot bool) {
+	// If we've already been through this once, no need to try again.
+	if os.Geteuid() == 0 && IsRootless() {
+		return
+	}
+
+	var uidNum, gidNum uint64
+	// Figure out who we are.
+	me, err := user.Current()
+	if !os.IsNotExist(err) {
+		bailOnError(err, "error determining current user")
+		uidNum, err = strconv.ParseUint(me.Uid, 10, 32)
+		bailOnError(err, "error parsing current UID %s", me.Uid)
+		gidNum, err = strconv.ParseUint(me.Gid, 10, 32)
+		bailOnError(err, "error parsing current GID %s", me.Gid)
+	}
+
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	// ID mappings to use to reexec ourselves.
+	var uidmap, gidmap []specs.LinuxIDMapping
+	if uidNum != 0 || evenForRoot {
+		// Read the set of ID mappings that we're allowed to use.  Each
+		// range in /etc/subuid and /etc/subgid file is a starting host
+		// ID and a range size.
+		uidmap, gidmap, err = GetSubIDMappings(me.Username, me.Username)
+		if err != nil {
+			logrus.Warnf("error reading allowed ID mappings: %v", err)
+		}
+		if len(uidmap) == 0 {
+			logrus.Warnf("Found no UID ranges set aside for user %q in /etc/subuid.", me.Username)
+		}
+		if len(gidmap) == 0 {
+			logrus.Warnf("Found no GID ranges set aside for user %q in /etc/subgid.", me.Username)
+		}
+		// Map our UID and GID, then the subuid and subgid ranges,
+		// consecutively, starting at 0, to get the mappings to use for
+		// a copy of ourselves.
+		uidmap = append([]specs.LinuxIDMapping{{HostID: uint32(uidNum), ContainerID: 0, Size: 1}}, uidmap...)
+		gidmap = append([]specs.LinuxIDMapping{{HostID: uint32(gidNum), ContainerID: 0, Size: 1}}, gidmap...)
+		var rangeStart uint32
+		for i := range uidmap {
+			uidmap[i].ContainerID = rangeStart
+			rangeStart += uidmap[i].Size
+		}
+		rangeStart = 0
+		for i := range gidmap {
+			gidmap[i].ContainerID = rangeStart
+			rangeStart += gidmap[i].Size
+		}
+	} else {
+		// If we have CAP_SYS_ADMIN, then we don't need to create a new namespace in order to be able
+		// to use unshare(), so don't bother creating a new user namespace at this point.
+		capabilities, err := capability.NewPid(0)
+		bailOnError(err, "error reading the current capabilities sets")
+		if capabilities.Get(capability.EFFECTIVE, capability.CAP_SYS_ADMIN) {
+			return
+		}
+		// Read the set of ID mappings that we're currently using.
+		uidmap, gidmap, err = GetHostIDMappings("")
+		bailOnError(err, "error reading current ID mappings")
+		// Just reuse them.
+		for i := range uidmap {
+			uidmap[i].HostID = uidmap[i].ContainerID
+		}
+		for i := range gidmap {
+			gidmap[i].HostID = gidmap[i].ContainerID
+		}
+	}
+
+	// Unlike most uses of reexec or unshare, we're using a name that
+	// _won't_ be recognized as a registered reexec handler, since we
+	// _want_ to fall through reexec.Init() to the normal main().
+	cmd := Command(append([]string{fmt.Sprintf("%s-in-a-user-namespace", os.Args[0])}, os.Args[1:]...)...)
+
+	// If, somehow, we don't become UID 0 in our child, indicate that the child shouldn't try again.
+	err = os.Setenv(UsernsEnvName, "1")
+	bailOnError(err, "error setting %s=1 in environment", UsernsEnvName)
+
+	// Set the default isolation type to use the "rootless" method.
+	if _, present := os.LookupEnv("BUILDAH_ISOLATION"); !present {
+		if err = os.Setenv("BUILDAH_ISOLATION", "rootless"); err != nil {
+			if err := os.Setenv("BUILDAH_ISOLATION", "rootless"); err != nil {
+				logrus.Errorf("error setting BUILDAH_ISOLATION=rootless in environment: %v", err)
+				os.Exit(1)
+			}
+		}
+	}
+
+	// Reuse our stdio.
+	cmd.Stdin = os.Stdin
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+
+	// Set up a new user namespace with the ID mapping.
+	cmd.UnshareFlags = syscall.CLONE_NEWUSER | syscall.CLONE_NEWNS
+	cmd.UseNewuidmap = uidNum != 0
+	cmd.UidMappings = uidmap
+	cmd.UseNewgidmap = uidNum != 0
+	cmd.GidMappings = gidmap
+	cmd.GidMappingsEnableSetgroups = true
+
+	// Finish up.
+	logrus.Debugf("running %+v with environment %+v, UID map %+v, and GID map %+v", cmd.Cmd.Args, os.Environ(), cmd.UidMappings, cmd.GidMappings)
+	ExecRunnable(cmd, nil)
+}
+
+// ExecRunnable runs the specified unshare command, captures its exit status,
+// and exits with the same status.
+func ExecRunnable(cmd Runnable, cleanup func()) {
+	exit := func(status int) {
+		if cleanup != nil {
+			cleanup()
+		}
+		os.Exit(status)
+	}
+	if err := cmd.Run(); err != nil {
+		if exitError, ok := errors.Cause(err).(*exec.ExitError); ok {
+			if exitError.ProcessState.Exited() {
+				if waitStatus, ok := exitError.ProcessState.Sys().(syscall.WaitStatus); ok {
+					if waitStatus.Exited() {
+						logrus.Errorf("%v", exitError)
+						exit(waitStatus.ExitStatus())
+					}
+					if waitStatus.Signaled() {
+						logrus.Errorf("%v", exitError)
+						exit(int(waitStatus.Signal()) + 128)
+					}
+				}
+			}
+		}
+		logrus.Errorf("%v", err)
+		logrus.Errorf("(unable to determine exit status)")
+		exit(1)
+	}
+	exit(0)
+}
+
+// getHostIDMappings reads mappings from the named node under /proc.
+func getHostIDMappings(path string) ([]specs.LinuxIDMapping, error) {
+	var mappings []specs.LinuxIDMapping
+	f, err := os.Open(path)
+	if err != nil {
+		return nil, errors.Wrapf(err, "error reading ID mappings from %q", path)
+	}
+	defer f.Close()
+	scanner := bufio.NewScanner(f)
+	for scanner.Scan() {
+		line := scanner.Text()
+		fields := strings.Fields(line)
+		if len(fields) != 3 {
+			return nil, errors.Errorf("line %q from %q has %d fields, not 3", line, path, len(fields))
+		}
+		cid, err := strconv.ParseUint(fields[0], 10, 32)
+		if err != nil {
+			return nil, errors.Wrapf(err, "error parsing container ID value %q from line %q in %q", fields[0], line, path)
+		}
+		hid, err := strconv.ParseUint(fields[1], 10, 32)
+		if err != nil {
+			return nil, errors.Wrapf(err, "error parsing host ID value %q from line %q in %q", fields[1], line, path)
+		}
+		size, err := strconv.ParseUint(fields[2], 10, 32)
+		if err != nil {
+			return nil, errors.Wrapf(err, "error parsing size value %q from line %q in %q", fields[2], line, path)
+		}
+		mappings = append(mappings, specs.LinuxIDMapping{ContainerID: uint32(cid), HostID: uint32(hid), Size: uint32(size)})
+	}
+	return mappings, nil
+}
+
+// GetHostIDMappings reads mappings for the specified process (or the current
+// process if pid is "self" or an empty string) from the kernel.
+func GetHostIDMappings(pid string) ([]specs.LinuxIDMapping, []specs.LinuxIDMapping, error) {
+	if pid == "" {
+		pid = "self"
+	}
+	uidmap, err := getHostIDMappings(fmt.Sprintf("/proc/%s/uid_map", pid))
+	if err != nil {
+		return nil, nil, err
+	}
+	gidmap, err := getHostIDMappings(fmt.Sprintf("/proc/%s/gid_map", pid))
+	if err != nil {
+		return nil, nil, err
+	}
+	return uidmap, gidmap, nil
+}
+
+// GetSubIDMappings reads mappings from /etc/subuid and /etc/subgid.
+func GetSubIDMappings(user, group string) ([]specs.LinuxIDMapping, []specs.LinuxIDMapping, error) {
+	mappings, err := idtools.NewIDMappings(user, group)
+	if err != nil {
+		return nil, nil, errors.Wrapf(err, "error reading subuid mappings for user %q and subgid mappings for group %q", user, group)
+	}
+	var uidmap, gidmap []specs.LinuxIDMapping
+	for _, m := range mappings.UIDs() {
+		uidmap = append(uidmap, specs.LinuxIDMapping{
+			ContainerID: uint32(m.ContainerID),
+			HostID:      uint32(m.HostID),
+			Size:        uint32(m.Size),
+		})
+	}
+	for _, m := range mappings.GIDs() {
+		gidmap = append(gidmap, specs.LinuxIDMapping{
+			ContainerID: uint32(m.ContainerID),
+			HostID:      uint32(m.HostID),
+			Size:        uint32(m.Size),
+		})
+	}
+	return uidmap, gidmap, nil
+}
+
+// ParseIDMappings parses mapping triples.
+func ParseIDMappings(uidmap, gidmap []string) ([]idtools.IDMap, []idtools.IDMap, error) {
+	uid, err := idtools.ParseIDMap(uidmap, "userns-uid-map")
+	if err != nil {
+		return nil, nil, err
+	}
+	gid, err := idtools.ParseIDMap(gidmap, "userns-gid-map")
+	if err != nil {
+		return nil, nil, err
+	}
+	return uid, gid, nil
+}

vendor/github.com/containers/storage/pkg/unshare/unshare_unsupported.go

@@ -0,0 +1,45 @@
+// +build !linux
+
+package unshare
+
+import (
+	"os"
+
+	"github.com/containers/storage/pkg/idtools"
+	"github.com/opencontainers/runtime-spec/specs-go"
+)
+
+const (
+	// UsernsEnvName is the environment variable, if set indicates in rootless mode
+	UsernsEnvName = "_CONTAINERS_USERNS_CONFIGURED"
+)
+
+// IsRootless tells us if we are running in rootless mode
+func IsRootless() bool {
+	return false
+}
+
+// GetRootlessUID returns the UID of the user in the parent userNS
+func GetRootlessUID() int {
+	return os.Getuid()
+}
+
+// RootlessEnv returns the environment settings for the rootless containers
+func RootlessEnv() []string {
+	return append(os.Environ(), UsernsEnvName+"=")
+}
+
+// MaybeReexecUsingUserNamespace re-exec the process in a new namespace
+func MaybeReexecUsingUserNamespace(evenForRoot bool) {
+}
+
+// GetHostIDMappings reads mappings for the specified process (or the current
+// process if pid is "self" or an empty string) from the kernel.
+func GetHostIDMappings(pid string) ([]specs.LinuxIDMapping, []specs.LinuxIDMapping, error) {
+	return nil, nil, nil
+}
+
+// ParseIDMappings parses mapping triples.
+func ParseIDMappings(uidmap, gidmap []string) ([]idtools.IDMap, []idtools.IDMap, error) {
+	return nil, nil, nil
+}

vendor/github.com/containers/storage/pkg/unshare/unshare_unsupported_cgo.go

@@ -0,0 +1,10 @@
+// +build !linux,cgo
+
+package unshare
+
+// Go refuses to compile a subpackage with CGO_ENABLED=1 if there is a *.c file but no 'import "C"'.
+// OTOH if we did have an 'import "C"', the Linux-only code would fail to compile.
+// So, satisfy the Go compiler by using import "C" but #ifdef-ing out all of the code.
+
+// #cgo CPPFLAGS: -DUNSHARE_NO_CODE_AT_ALL
+import "C"