Sébastien Han
f2313d6db0
Trying to execute a binary from the host within the container can result in mismatched libraries. The host version is compiled with paths of libraries on the host where the libs inside the container can differ. Because the path is known and we only need to make sure whether the bin exists or not then simply doing a lookup when we fallback on /rootfs is sufficient. Closes: https://github.com/rook/rook/issues/6078 Signed-off-by: Sébastien Han <seb@redhat.com>
97 lines
2.7 KiB
Go
97 lines
2.7 KiB
Go
/*
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Copyright 2020 The Rook Authors. All rights reserved.
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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 osd
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import (
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"fmt"
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"os"
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"path/filepath"
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"github.com/pkg/errors"
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"github.com/rook/rook/pkg/clusterd"
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)
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const (
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// mountNsPath is the default mount namespace of the host
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mountNsPath = "/rootfs/proc/1/ns/mnt"
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// nsenterCmd is the nsenter command
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nsenterCmd = "nsenter"
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rootFSPath = "/rootfs"
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)
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var (
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binPathsToCheck = []string{"/usr/sbin", "/sbin/"}
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)
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// NSEnter is an nsenter object
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type NSEnter struct {
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context *clusterd.Context
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binary string
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binaryArgs []string
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}
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// NewNsenter returns an instance of the NSEnter object
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func NewNsenter(context *clusterd.Context, binary string, binaryArgs []string) *NSEnter {
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return &NSEnter{
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context: context,
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binary: binary,
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binaryArgs: binaryArgs,
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}
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}
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func (ne *NSEnter) buildNsEnterCLI(binPath string) []string {
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baseArgs := []string{fmt.Sprintf("--mount=%s", mountNsPath), "--", binPath}
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baseArgs = append(baseArgs, ne.binaryArgs...)
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return baseArgs
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}
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func (ne *NSEnter) callNsEnter(binPath string) error {
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args := ne.buildNsEnterCLI(binPath)
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op, err := ne.context.Executor.ExecuteCommandWithCombinedOutput(nsenterCmd, args...)
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if err != nil {
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return errors.Wrapf(err, "failed to execute nsenter. output: %s", op)
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}
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logger.Info("successfully called nsenter")
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return nil
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}
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func (ne *NSEnter) checkIfBinaryExistsOnHost() error {
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for _, path := range binPathsToCheck {
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binPath := filepath.Join(path, ne.binary)
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// Check with nsenter first
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err := ne.callNsEnter(binPath)
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if err != nil {
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logger.Debugf("failed to call nsenter. %v", err)
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// If nsenter failed, let's try with the rootfs directly but only lookup the binary and do not execute it
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// This avoids mismatch libraries between the container and the host while executing
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rootFSBinPath := filepath.Join(rootFSPath, binPath)
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_, err := os.Stat(rootFSBinPath)
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if err != nil {
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logger.Debugf("failed to lookup binary path %q on the host rootfs. %v", rootFSBinPath, err)
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continue
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}
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binPath = rootFSBinPath
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}
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logger.Infof("binary %q found on the host, proceeding with osd preparation", binPath)
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return nil
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}
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return errors.Errorf("binary %q does not exist on the host", ne.binary)
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}
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