build(deps): bump github.com/rootless-containers/rootlesskit

Bumps [github.com/rootless-containers/rootlesskit](https://github.com/rootless-containers/rootlesskit) from 0.9.3 to 0.9.4.
- [Release notes](https://github.com/rootless-containers/rootlesskit/releases)
- [Commits](https://github.com/rootless-containers/rootlesskit/compare/v0.9.3...v0.9.4)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>
Signed-off-by: Valentin Rothberg <rothberg@redhat.com>

4 files changed, 43 insertions, 4 deletions

diff --git a/go.mod b/go.mod
index 09077188c..576166df0 100644
--- a/go.mod
+++ b/go.mod
@@ -45,7 +45,7 @@ require (
 	github.com/opentracing/opentracing-go v1.1.0
 	github.com/pkg/errors v0.9.1
 	github.com/pmezard/go-difflib v1.0.0
-	github.com/rootless-containers/rootlesskit v0.9.3
+	github.com/rootless-containers/rootlesskit v0.9.4
 	github.com/seccomp/containers-golang v0.0.0-20190312124753-8ca8945ccf5f
 	github.com/sirupsen/logrus v1.5.0
 	github.com/spf13/cobra v0.0.7
diff --git a/go.sum b/go.sum
index 92ea6f545..167d52e0a 100644
--- a/go.sum
+++ b/go.sum
@@ -373,8 +373,8 @@ github.com/prometheus/procfs v0.0.5/go.mod h1:4A/X28fw3Fc593LaREMrKMqOKvUAntwMDa
 github.com/prometheus/tsdb v0.7.1/go.mod h1:qhTCs0VvXwvX/y3TZrWD7rabWM+ijKTux40TwIPHuXU=
 github.com/remyoudompheng/bigfft v0.0.0-20170806203942-52369c62f446/go.mod h1:uYEyJGbgTkfkS4+E/PavXkNJcbFIpEtjt2B0KDQ5+9M=
 github.com/rogpeppe/fastuuid v0.0.0-20150106093220-6724a57986af/go.mod h1:XWv6SoW27p1b0cqNHllgS5HIMJraePCO15w5zCzIWYg=
-github.com/rootless-containers/rootlesskit v0.9.3 h1:hrkZzBZT5vEnhAso6H1jHAcc4DT8h6/hp2z4yL0xu/8=
-github.com/rootless-containers/rootlesskit v0.9.3/go.mod h1:fx5DhInDgnR0Upj+2cOVacKuZJYSNKV5P/bCwGa+quQ=
+github.com/rootless-containers/rootlesskit v0.9.4 h1:6ogX7l3r3nlS7eTB8ePbLSQ6TZR1aVQzRjTy2SIBOzk=
+github.com/rootless-containers/rootlesskit v0.9.4/go.mod h1:fx5DhInDgnR0Upj+2cOVacKuZJYSNKV5P/bCwGa+quQ=
 github.com/russross/blackfriday/v2 v2.0.1/go.mod h1:+Rmxgy9KzJVeS9/2gXHxylqXiyQDYRxCVz55jmeOWTM=
 github.com/safchain/ethtool v0.0.0-20190326074333-42ed695e3de8 h1:2c1EFnZHIPCW8qKWgHMH/fX2PkSabFc5mrVzfUNdg5U=
 github.com/safchain/ethtool v0.0.0-20190326074333-42ed695e3de8/go.mod h1:Z0q5wiBQGYcxhMZ6gUqHn6pYNLypFAvaL3UvgZLR0U4=
diff --git a/vendor/github.com/rootless-containers/rootlesskit/pkg/port/builtin/parent/parent.go b/vendor/github.com/rootless-containers/rootlesskit/pkg/port/builtin/parent/parent.go
index 893bf1da9..8ffadd859 100644
--- a/vendor/github.com/rootless-containers/rootlesskit/pkg/port/builtin/parent/parent.go
+++ b/vendor/github.com/rootless-containers/rootlesskit/pkg/port/builtin/parent/parent.go
@@ -2,11 +2,14 @@ package parent
 
 import (
 	"context"
+	"fmt"
 	"io"
 	"io/ioutil"
 	"net"
 	"os"
 	"path/filepath"
+	"strconv"
+	"strings"
 	"sync"
 	"syscall"
 
@@ -84,6 +87,39 @@ func (d *driver) RunParentDriver(initComplete chan struct{}, quit <-chan struct{
 	return nil
 }
 
+func isEPERM(err error) bool {
+	k := "permission denied"
+	// As of Go 1.14, errors.Is(err, syscall.EPERM) does not seem to work for
+	// "listen tcp 0.0.0.0:80: bind: permission denied" error from net.ListenTCP().
+	return errors.Is(err, syscall.EPERM) || strings.Contains(err.Error(), k)
+}
+
+// annotateEPERM annotates origErr for human-readability
+func annotateEPERM(origErr error, spec port.Spec) error {
+	// Read "net.ipv4.ip_unprivileged_port_start" value (typically 1024)
+	// TODO: what for IPv6?
+	// NOTE: sync.Once should not be used here
+	b, e := ioutil.ReadFile("/proc/sys/net/ipv4/ip_unprivileged_port_start")
+	if e != nil {
+		return origErr
+	}
+	start, e := strconv.Atoi(strings.TrimSpace(string(b)))
+	if e != nil {
+		return origErr
+	}
+	if spec.ParentPort >= start {
+		// origErr is unrelated to ip_unprivileged_port_start
+		return origErr
+	}
+	text := fmt.Sprintf("cannot expose privileged port %d, you might need to add \"net.ipv4.ip_unprivileged_port_start=0\" (currently %d) to /etc/sysctl.conf", spec.ParentPort, start)
+	if filepath.Base(os.Args[0]) == "rootlesskit" {
+		// NOTE: The following sentence is appended only if Args[0] == "rootlesskit", because it does not apply to Podman (as of Podman v1.9).
+		// Podman launches the parent driver in the child user namespace (but in the parent network namespace), which disables the file capability.
+		text += ", or set CAP_NET_BIND_SERVICE on rootlesskit binary"
+	}
+	return errors.Wrap(origErr, text)
+}
+
 func (d *driver) AddPort(ctx context.Context, spec port.Spec) (*port.Status, error) {
 	d.mu.Lock()
 	err := portutil.ValidatePortSpec(spec, d.ports)
@@ -106,6 +142,9 @@ func (d *driver) AddPort(ctx context.Context, spec port.Spec) (*port.Status, err
 		return nil, errors.New("spec was not validated?")
 	}
 	if err != nil {
+		if isEPERM(err) {
+			err = annotateEPERM(err, spec)
+		}
 		return nil, err
 	}
 	d.mu.Lock()
diff --git a/vendor/modules.txt b/vendor/modules.txt
index 782a905a1..0a6d8ccd5 100644
--- a/vendor/modules.txt
+++ b/vendor/modules.txt
@@ -454,7 +454,7 @@ github.com/prometheus/common/model
 github.com/prometheus/procfs
 github.com/prometheus/procfs/internal/fs
 github.com/prometheus/procfs/internal/util
-# github.com/rootless-containers/rootlesskit v0.9.3
+# github.com/rootless-containers/rootlesskit v0.9.4
 github.com/rootless-containers/rootlesskit/pkg/msgutil
 github.com/rootless-containers/rootlesskit/pkg/port
 github.com/rootless-containers/rootlesskit/pkg/port/builtin