restrict pprof-addr to localhost

[adam-mateen]

Description of the issue

Avoid potential misconfiguration exposing agent debug info externally.

Description of changes

Improved the --help text for the --prof-addr option.
Added a check to ensure that the address is localhost:nnnn

License

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

Tests

• Manual testing:

amazon-cloudwatch-agent --pprof-addr 123
2023-10-06T14:46:12Z W! Not starting pprof, it is restricted to localhost:nnnn
2023-10-06T14:46:12Z E! [telegraf] Error running agent: no config file specified

amazon-cloudwatch-agent --pprof-addr localhost
2023-10-06T14:46:18Z I! Starting pprof HTTP server at: http://localhost/debug/pprof
2023-10-06T14:46:18Z E! [telegraf] Error running agent: no config file specified
2023-10-06T14:46:18Z E! listen tcp: address localhost: missing port in address

amazon-cloudwatch-agent --pprof-addr localhost:123
2023-10-06T14:46:26Z I! Starting pprof HTTP server at: http://localhost:123/debug/pprof
2023-10-06T14:46:26Z E! [telegraf] Error running agent: no config file specified

amazon-cloudwatch-agent --pprof-addr :123         
2023-10-06T14:46:39Z I! Starting pprof HTTP server at: http://localhost:123/debug/pprof
2023-10-06T14:46:39Z E! [telegraf] Error running agent: no config file specified

amazon-cloudwatch-agent --pprof-addr lokalhost:8090
2023-10-06T14:47:04Z W! Not starting pprof, it is restricted to localhost:nnnn
2023-10-06T14:47:04Z E! [telegraf] Error running agent: no config file specified

--help output looks like this:

  -otelconfig string
    	YAML configuration file to run OTel pipeline
  -output-filter string
    	filter the outputs to enable, separator is :
  -output-list
    	print available output plugins.
  -pidfile string
    	file to write our pid to
  -pprof-addr string
    	pprof address to listen on, disabled by default, examples: 'localhost:1234', ':4567' (restricted to localhost)

Requirements

Before commit the code, please do the following steps.

1. Run make fmt and make fmt-sh
2. Run make lint

[codecov-commenter]

Codecov Report

Attention: 37 lines in your changes are missing coverage. Please review.

Comparison is base (96d4763) 57.58% compared to head (15e57df) 62.66%.
Report is 418 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #893      +/-   ##
==========================================
+ Coverage   57.58%   62.66%   +5.08%     
==========================================
  Files         370      338      -32     
  Lines       17548    17009     -539     
==========================================
+ Hits        10105    10659     +554     
+ Misses       6848     5796    -1052     
+ Partials      595      554      -41     

Files	Coverage Δ
cfg/commonconfig/commonconfig.go	8.00% <ø> (ø)
...md/amazon-cloudwatch-agent-config-wizard/wizard.go	59.55% <ø> (-8.51%)	⬇️
...amazon-cloudwatch-agent/amazon-cloudwatch-agent.go	2.66% <ø> (ø)
...oudwatch-agent/register_event_logger_notwindows.go	0.00% <ø> (ø)
...-cloudwatch-agent/register_event_logger_windows.go	0.00% <ø> (ø)
cmd/config-translator/translator.go	0.00% <ø> (ø)
cmd/xray-migration/commands_unix.go	42.50% <ø> (ø)
cmd/xray-migration/commands_windows.go	42.50% <ø> (ø)
cmd/xray-migration/xray-migration.go	30.28% <ø> (ø)
handlers/agentinfo/info.go	84.94% <ø> (ø)
... and 22 more

... and 207 files with indirect coverage changes

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.