Source: golang-github-containers-psgo
Version: 1.5.2-1
Severity: important
Tags: patch
X-Debbugs-Cc: vignesh.ra...@collabora.com
Dear Maintainer,
The following vulnerability for golang-github-containers-psgo is fixed in
bookworm,
https://security-tracker.debian.org/tracker/CVE-2022-1227
We have backported the CVE fixes to bullseye since we are working on
debian bullseye derivative and want to send the patches to debian.
We understand these issues are not DSA and have to go though a point
release.
Please could you review the attached patch and apply in bullseye.
Have created a merge request also for review
https://salsa.debian.org/go-team/packages/golang-github-containers-psgo/-/merge_requests/2
Regards,
Vignesh
-- System Information:
Debian Release: 11.1
APT prefers stable
APT policy: (700, 'stable'), (650, 'testing'), (600, 'unstable'), (500,
'stable-updates'), (500, 'stable-security')
Architecture: amd64 (x86_64)
Kernel: Linux 5.10.0-9-amd64 (SMP w/8 CPU threads)
Kernel taint flags: TAINT_OOT_MODULE
Locale: LANG=en_IN, LC_CTYPE=en_IN (charmap=UTF-8), LANGUAGE=en_IN:en
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled
>From 0f799b8698f0e180b19679bb05213303189c929f Mon Sep 17 00:00:00 2001
From: Andre Moreira Magalhaes <andru...@gmail.com>
Date: Mon, 19 Sep 2022 13:59:39 -0300
Subject: [PATCH] internal: proc: do not join the process user namespace
The only reason we joined the process user namespace was to map a
handful of fields into the same usernamepsace as that process. This
procedure can be implemented entirely in Go without having to run code
inside the container.
In addition, since psgo is used inside "podman top", we were actually
executing the nsenter binary *from the container* without all of the
container's security profiles applied. At the very least this would
allow a container process to return bad data to psgo (possibly confusing
management scripts using psgo) and at the very worst it would allow the
container process to escalate privileges by getting podman to execute
code without all of the container security profiles applied.
Fixes: CVE-2022-1227
(backported from upstream commit d9466da9f563a9de1ece79dcae86b37b1db75443)
---
internal/proc/ns.go | 15 ++----
internal/proc/status.go | 102 +++++++++++++++++++++++++++++-----------
psgo.go | 35 +++-----------
3 files changed, 86 insertions(+), 66 deletions(-)
diff --git a/internal/proc/ns.go b/internal/proc/ns.go
index 53e5ebd..6671141 100644
--- a/internal/proc/ns.go
+++ b/internal/proc/ns.go
@@ -20,15 +20,10 @@ import (
"io"
"os"
+ "github.com/containers/storage/pkg/idtools"
"github.com/pkg/errors"
)
-type IDMap struct {
- ContainerID int
- HostID int
- Size int
-}
-
// ParsePIDNamespace returns the content of /proc/$pid/ns/pid.
func ParsePIDNamespace(pid string) (string, error) {
pidNS, err := os.Readlink(fmt.Sprintf("/proc/%s/ns/pid", pid))
@@ -48,14 +43,14 @@ func ParseUserNamespace(pid string) (string, error) {
}
// ReadMappings reads the user namespace mappings at the specified path
-func ReadMappings(path string) ([]IDMap, error) {
+func ReadMappings(path string) ([]idtools.IDMap, error) {
file, err := os.Open(path)
if err != nil {
return nil, errors.Wrapf(err, "cannot open %s", path)
}
defer file.Close()
- mappings := []IDMap{}
+ var mappings []idtools.IDMap
buf := bufio.NewReader(file)
for {
@@ -70,10 +65,10 @@ func ReadMappings(path string) ([]IDMap, error) {
return mappings, nil
}
- containerID, hostID, size := 0, 0, 0
+ var containerID, hostID, size int
if _, err := fmt.Sscanf(string(line), "%d %d %d", &containerID,
&hostID, &size); err != nil {
return nil, errors.Wrapf(err, "cannot parse %s",
string(line))
}
- mappings = append(mappings, IDMap{ContainerID: containerID,
HostID: hostID, Size: size})
+ mappings = append(mappings, idtools.IDMap{ContainerID:
containerID, HostID: hostID, Size: size})
}
}
diff --git a/internal/proc/status.go b/internal/proc/status.go
index df31139..3f79a5b 100644
--- a/internal/proc/status.go
+++ b/internal/proc/status.go
@@ -17,10 +17,13 @@ package proc
import (
"bufio"
"fmt"
+ "io/ioutil"
"os"
- "os/exec"
+ "strconv"
"strings"
+ "sync"
+ "github.com/containers/storage/pkg/idtools"
"github.com/pkg/errors"
)
@@ -175,23 +178,8 @@ type Status struct {
NonvoluntaryCtxtSwitches string
}
-// readStatusUserNS joins the user namespace of pid and returns the content of
-// /proc/pid/status as a string slice.
-func readStatusUserNS(pid string) ([]string, error) {
- path := fmt.Sprintf("/proc/%s/status", pid)
- args := []string{"nsenter", "-U", "-t", pid, "cat", path}
-
- c := exec.Command(args[0], args[1:]...)
- output, err := c.CombinedOutput()
- if err != nil {
- return nil, fmt.Errorf("error executing %q: %v",
strings.Join(args, " "), err)
- }
-
- return strings.Split(string(output), "\n"), nil
-}
-
-// readStatusDefault returns the content of /proc/pid/status as a string slice.
-func readStatusDefault(pid string) ([]string, error) {
+// readStatus returns the content of /proc/pid/status as a string slice.
+func readStatus(pid string) ([]string, error) {
path := fmt.Sprintf("/proc/%s/status", pid)
f, err := os.Open(path)
if err != nil {
@@ -205,21 +193,81 @@ func readStatusDefault(pid string) ([]string, error) {
return lines, nil
}
-// ParseStatus parses the /proc/$pid/status file and returns a *Status.
-func ParseStatus(pid string, joinUserNS bool) (*Status, error) {
- var lines []string
- var err error
+// mapField maps a single string-typed ID field given the set of mappings. If
+// no mapping exists, the overflow uid/gid is used.
+func mapStatusField(field *string, mapping []idtools.IDMap, overflow string) {
+ hostId, err := strconv.Atoi(*field)
+ if err != nil {
+ *field = overflow
+ return
+ }
+ contId, err := idtools.RawToContainer(hostId, mapping)
+ if err != nil {
+ *field = overflow
+ return
+ }
+ *field = strconv.Itoa(contId)
+}
+
+var (
+ overflowOnce sync.Once
+ overflowUid = "65534"
+ overflowGid = "65534"
+)
+
+func overflowIds() (string, string) {
+ overflowOnce.Do(func() {
+ if uid, err := ioutil.ReadFile("/proc/sys/kernel/overflowuid");
err == nil {
+ overflowUid = strings.TrimSpace(string(uid))
+ }
+ if gid, err := ioutil.ReadFile("/proc/sys/kernel/overflowgid");
err == nil {
+ overflowGid = strings.TrimSpace(string(gid))
+ }
+ })
+ return overflowUid, overflowGid
+}
- if joinUserNS {
- lines, err = readStatusUserNS(pid)
- } else {
- lines, err = readStatusDefault(pid)
+// mapStatus takes a Status struct and remaps all of the relevant fields to
+// match the user namespace of the target process.
+func mapStatus(pid string, status *Status) (*Status, error) {
+ uidMap, err := ReadMappings(fmt.Sprintf("/proc/%s/uid_map", pid))
+ if err != nil {
+ return nil, err
+ }
+ gidMap, err := ReadMappings(fmt.Sprintf("/proc/%s/gid_map", pid))
+ if err != nil {
+ return nil, err
+ }
+ overflowUid, overflowGid := overflowIds()
+ for i := range status.Uids {
+ mapStatusField(&status.Uids[i], uidMap, overflowUid)
+ }
+ for i := range status.Gids {
+ mapStatusField(&status.Gids[i], gidMap, overflowGid)
}
+ for i := range status.Groups {
+ mapStatusField(&status.Groups[i], gidMap, overflowGid)
+ }
+ return status, nil
+}
+// ParseStatus parses the /proc/$pid/status file and returns a *Status.
+func ParseStatus(pid string, mapUserNS bool) (*Status, error) {
+ lines, err := readStatus(pid)
+ if err != nil {
+ return nil, err
+ }
+ status, err := parseStatus(pid, lines)
if err != nil {
return nil, err
}
- return parseStatus(pid, lines)
+ if mapUserNS {
+ status, err = mapStatus(pid, status)
+ if err != nil {
+ return nil, err
+ }
+ }
+ return status, nil
}
// parseStatus extracts data from lines and returns a *Status.
diff --git a/psgo.go b/psgo.go
index 7c74fd7..5823f37 100644
--- a/psgo.go
+++ b/psgo.go
@@ -40,29 +40,19 @@ import (
"github.com/containers/psgo/internal/dev"
"github.com/containers/psgo/internal/proc"
"github.com/containers/psgo/internal/process"
+ "github.com/containers/storage/pkg/idtools"
"github.com/pkg/errors"
"golang.org/x/sys/unix"
)
-// IDMap specifies a mapping range from the host to the container IDs.
-type IDMap struct {
- // ContainerID is the first ID in the container.
- ContainerID int
- // HostID is the first ID in the host.
- HostID int
- // Size specifies how long is the range. e.g. 1 means a single user
- // is mapped.
- Size int
-}
-
// JoinNamespaceOpts specifies different options for joining the specified
namespaces.
type JoinNamespaceOpts struct {
// UIDMap specifies a mapping for UIDs in the container. If specified
// huser will perform the reverse mapping.
- UIDMap []IDMap
+ UIDMap []idtools.IDMap
// GIDMap specifies a mapping for GIDs in the container. If specified
// hgroup will perform the reverse mapping.
- GIDMap []IDMap
+ GIDMap []idtools.IDMap
// FillMappings specified whether UIDMap and GIDMap must be initialized
// with the current user namespace.
@@ -102,7 +92,7 @@ type aixFormatDescriptor struct {
}
// findID converts the specified id to the host mapping
-func findID(idStr string, mapping []IDMap, lookupFunc func(uid string)
(string, error), overflowFile string) (string, error) {
+func findID(idStr string, mapping []idtools.IDMap, lookupFunc func(uid string)
(string, error), overflowFile string) (string, error) {
if len(mapping) == 0 {
return idStr, nil
}
@@ -339,29 +329,16 @@ func JoinNamespaceAndProcessInfo(pid string, descriptors
[]string) ([][]string,
return JoinNamespaceAndProcessInfoWithOptions(pid, descriptors,
&JoinNamespaceOpts{})
}
-func readMappings(path string) ([]IDMap, error) {
- mappings, err := proc.ReadMappings(path)
- if err != nil {
- return nil, err
- }
- var res []IDMap
- for _, i := range mappings {
- m := IDMap{ContainerID: i.ContainerID, HostID: i.HostID, Size:
i.Size}
- res = append(res, m)
- }
- return res, nil
-}
-
func contextFromOptions(options *JoinNamespaceOpts) (*psContext, error) {
ctx := new(psContext)
ctx.opts = options
if ctx.opts != nil && ctx.opts.FillMappings {
- uidMappings, err := readMappings("/proc/self/uid_map")
+ uidMappings, err := proc.ReadMappings("/proc/self/uid_map")
if err != nil {
return nil, err
}
- gidMappings, err := readMappings("/proc/self/gid_map")
+ gidMappings, err := proc.ReadMappings("/proc/self/gid_map")
if err != nil {
return nil, err
}
--
2.37.2
