fix(lockfiles): fix privileges in lockfile scan

[MaineK00n]

What did you implement:

lockfile scan searches for the target lockfile and retrieves its contents from the scan destination.
Until now, even in fast-root mode, all command execution has been done as the executing user.
This PR grants privileges to the command according to its execution mode.

Type of change

• Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

env

$ vagrant ssh
vagrant@ubuntu-focal:~$ find / -type f -and -name "Cargo.lock" 2>&1 | grep -v "find:"
vagrant@ubuntu-focal:~$ sudo find / -type f -and -name "Cargo.lock" 2>&1 | grep -v "find:"
/root/Cargo.lock

findlock = true

• config.toml

[servers.vagrant]
host = "127.0.0.1"
port = "2222"
user = "vagrant"
keyPath            = "/home/mainek00n/github/github.com/MaineK00n/vuls-targets-docker/.ssh/id_rsa"
scanMode = ["fast-root"]
scanModules = ["lockfile"]
findLock = true

• before

$ vuls scan
[Aug  8 18:07:47]  INFO [localhost] vuls-v0.20.0-build-20220808_180441_1e45732
[Aug  8 18:07:47]  INFO [localhost] Start scanning
[Aug  8 18:07:47]  INFO [localhost] config: /home/mainek00n/github/github.com/MaineK00n/vuls/config.toml
[Aug  8 18:07:47]  INFO [localhost] Validating config...
[Aug  8 18:07:47]  INFO [localhost] Detecting Server/Container OS... 
[Aug  8 18:07:47]  INFO [localhost] Detecting OS of servers... 
[Aug  8 18:07:47]  INFO [localhost] (1/1) Detected: vagrant: ubuntu 20.04
[Aug  8 18:07:47]  INFO [localhost] Detecting OS of containers... 
[Aug  8 18:07:47]  INFO [localhost] Checking Scan Modes... 
[Aug  8 18:07:47]  INFO [localhost] Detecting Platforms... 
[Aug  8 18:07:48]  INFO [localhost] (1/1) vagrant is running on other
[Aug  8 18:07:48]  INFO [vagrant] Scanning Lockfile...


Scan Summary
================
vagrant	ubuntu20.04	0 installed, 0 updatable

• after

$ vuls scan
[Aug  8 18:27:44]  INFO [localhost] vuls-v0.20.0-build-20220808_182706_7ae7d4e
[Aug  8 18:27:44]  INFO [localhost] Start scanning
[Aug  8 18:27:44]  INFO [localhost] config: /home/mainek00n/github/github.com/MaineK00n/vuls/config.toml
[Aug  8 18:27:44]  INFO [localhost] Validating config...
[Aug  8 18:27:44]  INFO [localhost] Detecting Server/Container OS... 
[Aug  8 18:27:44]  INFO [localhost] Detecting OS of servers... 
[Aug  8 18:27:45]  INFO [localhost] (1/1) Detected: vagrant: ubuntu 20.04
[Aug  8 18:27:45]  INFO [localhost] Detecting OS of containers... 
[Aug  8 18:27:45]  INFO [localhost] Checking Scan Modes... 
[Aug  8 18:27:45]  INFO [localhost] Detecting Platforms... 
[Aug  8 18:27:46]  INFO [localhost] (1/1) vagrant is running on other
[Aug  8 18:27:46]  INFO [vagrant] Scanning Lockfile...


Scan Summary
================
vagrant	ubuntu20.04	0 installed, 0 updatable	399 libs

specify a path outside of the executing user privileges

• config.toml

[servers.vagrant]
host = "127.0.0.1"
port = "2222"
user = "vagrant"
keyPath            = "/home/mainek00n/github/github.com/MaineK00n/vuls-targets-docker/.ssh/id_rsa"
scanMode = ["fast-root"]
scanModules = ["lockfile"]
lockfiles = ["/root/Cargo.lock"]

• before

$ vuls scan
[Aug  8 18:30:38]  INFO [localhost] vuls-v0.20.0-build-20220808_180441_1e45732
[Aug  8 18:30:38]  INFO [localhost] Start scanning
[Aug  8 18:30:38]  INFO [localhost] config: /home/mainek00n/github/github.com/MaineK00n/vuls/config.toml
[Aug  8 18:30:38]  INFO [localhost] Validating config...
[Aug  8 18:30:38]  INFO [localhost] Detecting Server/Container OS... 
[Aug  8 18:30:38]  INFO [localhost] Detecting OS of servers... 
[Aug  8 18:30:38]  INFO [localhost] (1/1) Detected: vagrant: ubuntu 20.04
[Aug  8 18:30:38]  INFO [localhost] Detecting OS of containers... 
[Aug  8 18:30:38]  INFO [localhost] Checking Scan Modes... 
[Aug  8 18:30:38]  INFO [localhost] Detecting Platforms... 
[Aug  8 18:30:39]  INFO [localhost] (1/1) vagrant is running on other
[Aug  8 18:30:39]  INFO [vagrant] Scanning Lockfile...
[Aug  8 18:30:39] ERROR [localhost] Error on vagrant, err: [Failed to scan Library:
    github.com/future-architect/vuls/scanner.Scanner.getScanResults.func1
        /home/mainek00n/go/src/github.com/future-architect/vuls/scanner/scanner.go:888
  - Failed to get target file permission: execResult: servername: vagrant
      cmd: /usr/bin/ssh -tt -o StrictHostKeyChecking=yes -o LogLevel=quiet -o ConnectionAttempts=3 -o ConnectTimeout=10 -o ControlMaster=auto -o ControlPath=/home/mainek00n/.vuls/controlmaster-%r-vagrant.%p -o Controlpersist=10m -l vagrant -p 2222 -i /home/mainek00n/github/github.com/MaineK00n/vuls-targets-docker/.ssh/id_rsa -o PasswordAuthentication=no 127.0.0.1 stty cols 1000; stat -c "%a" /root/Cargo.lock
      exitstatus: 1
      stdout: stat: cannot stat '/root/Cargo.lock': Permission denied
    
      stderr: 
      err: %!s(<nil>), filepath: /root/Cargo.lock:
    github.com/future-architect/vuls/scanner.(*base).scanLibraries
        /home/mainek00n/go/src/github.com/future-architect/vuls/scanner/base.go:639]


Scan Summary
================
vagrant	Error		Use configtest subcommand or scan with --debug to view the details


[Aug  8 18:30:39] ERROR [localhost] Failed to scan: Failed to scan. err:
    github.com/future-architect/vuls/scanner.Scanner.Scan
        /home/mainek00n/go/src/github.com/future-architect/vuls/scanner/scanner.go:106
  - An error occurred on [vagrant]

• after

vuls scan
[Aug  8 18:32:33]  INFO [localhost] vuls-v0.20.0-build-20220808_182706_7ae7d4e
[Aug  8 18:32:33]  INFO [localhost] Start scanning
[Aug  8 18:32:33]  INFO [localhost] config: /home/mainek00n/github/github.com/MaineK00n/vuls/config.toml
[Aug  8 18:32:33]  INFO [localhost] Validating config...
[Aug  8 18:32:33]  INFO [localhost] Detecting Server/Container OS... 
[Aug  8 18:32:33]  INFO [localhost] Detecting OS of servers... 
[Aug  8 18:32:33]  INFO [localhost] (1/1) Detected: vagrant: ubuntu 20.04
[Aug  8 18:32:33]  INFO [localhost] Detecting OS of containers... 
[Aug  8 18:32:33]  INFO [localhost] Checking Scan Modes... 
[Aug  8 18:32:33]  INFO [localhost] Detecting Platforms... 
[Aug  8 18:32:34]  INFO [localhost] (1/1) vagrant is running on other
[Aug  8 18:32:34]  INFO [vagrant] Scanning Lockfile...


Scan Summary
================
vagrant	ubuntu20.04	0 installed, 0 updatable	399 libs

Checklist:

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• Write documentation
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Is this ready for review?: YES

Reference