117 lines
3.4 KiB
Go
117 lines
3.4 KiB
Go
/*
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Copyright 2016 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package sysctl
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import (
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"fmt"
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goruntime "runtime"
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"k8s.io/apimachinery/pkg/util/version"
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"k8s.io/klog/v2"
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"k8s.io/kubernetes/pkg/proxy/ipvs"
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)
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type sysctl struct {
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// the name of sysctl
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name string
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// the minimum kernel version where the sysctl is available
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kernel string
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}
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var safeSysctls = []sysctl{
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{
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name: "kernel.shm_rmid_forced",
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}, {
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name: "net.ipv4.ip_local_port_range",
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}, {
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name: "net.ipv4.tcp_syncookies",
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}, {
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name: "net.ipv4.ping_group_range",
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}, {
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name: "net.ipv4.ip_unprivileged_port_start",
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}, {
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name: "net.ipv4.ip_local_reserved_ports",
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// refer to https://github.com/torvalds/linux/commit/122ff243f5f104194750ecbc76d5946dd1eec934.
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kernel: "3.16",
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}, {
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name: "net.ipv4.tcp_keepalive_time",
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// refer to https://github.com/torvalds/linux/commit/13b287e8d1cad951634389f85b8c9b816bd3bb1e.
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kernel: "4.5",
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}, {
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// refer to https://github.com/torvalds/linux/commit/1e579caa18b96f9eb18f4f5416658cd15f37c062.
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name: "net.ipv4.tcp_fin_timeout",
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kernel: "4.6",
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},
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{
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// refer to https://github.com/torvalds/linux/commit/b840d15d39128d08ed4486085e5507d2617b9ae1.
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name: "net.ipv4.tcp_keepalive_intvl",
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kernel: "4.5",
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},
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{
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// refer to https://github.com/torvalds/linux/commit/9bd6861bd4326e3afd3f14a9ec8a723771fb20bb.
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name: "net.ipv4.tcp_keepalive_probes",
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kernel: "4.5",
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},
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}
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// SafeSysctlAllowlist returns the allowlist of safe sysctls and safe sysctl patterns (ending in *).
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//
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// A sysctl is called safe iff
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// - it is namespaced in the container or the pod
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// - it is isolated, i.e. has no influence on any other pod on the same node.
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func SafeSysctlAllowlist() []string {
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if goruntime.GOOS != "linux" {
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return nil
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}
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return getSafeSysctlAllowlist(getKernelVersion)
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}
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func getSafeSysctlAllowlist(getVersion func() (*version.Version, error)) []string {
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kernelVersion, err := getVersion()
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if err != nil {
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klog.ErrorS(err, "failed to get kernel version, unable to determine which sysctls are available")
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}
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var safeSysctlAllowlist []string
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for _, sc := range safeSysctls {
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if sc.kernel == "" {
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safeSysctlAllowlist = append(safeSysctlAllowlist, sc.name)
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continue
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}
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if kernelVersion != nil && kernelVersion.AtLeast(version.MustParseGeneric(sc.kernel)) {
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safeSysctlAllowlist = append(safeSysctlAllowlist, sc.name)
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} else {
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klog.InfoS("kernel version is too old, dropping the sysctl from safe sysctl list", "kernelVersion", kernelVersion, "sysctl", sc.name)
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}
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}
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return safeSysctlAllowlist
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}
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func getKernelVersion() (*version.Version, error) {
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kernelVersionStr, err := ipvs.NewLinuxKernelHandler().GetKernelVersion()
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if err != nil {
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return nil, fmt.Errorf("failed to get kernel version: %w", err)
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}
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kernelVersion, err := version.ParseGeneric(kernelVersionStr)
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if err != nil {
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return nil, fmt.Errorf("failed to parse kernel version: %w", err)
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}
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return kernelVersion, nil
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}
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