Added ability to hide sensative logs

[JackSeaton]

I know this isn't ready to be merged, but the main idea is there.

Below is an example of posting some splash code, along with some variables to be executed (I pretty printed the JSON for readability):

[-] Log opened.
[-] Splash version: 3.2
[-] Qt 5.9.1, PyQt 5.9, WebKit 602.1, sip 4.19.3, Twisted 16.1.1, Lua 5.2
[-] Python 3.5.2 (default, Nov 23 2017, 16:37:01) [GCC 5.4.0 20160609]
[-] Open files limit: 1048576
[-] Can't bump open files limit
[-] Xvfb is started: ['Xvfb', ':437071335', '-screen', '0', '1024x768x24', '-nolisten', 'tcp']
QStandardPaths: XDG_RUNTIME_DIR not set, defaulting to '/tmp/runtime-root'
[-] proxy profiles support is enabled, proxy profiles path: /etc/splash/proxy-profiles
[-] verbosity=1
[-] slots=50
[-] argument_cache_max_entries=500
[-] Web UI: enabled, Lua: enabled (sandbox: enabled)
[-] Server listening on 0.0.0.0:8050
[-] Site starting on 8050
[-] Starting factory <twisted.web.server.Site object at 0x7fd12b120a20>
libpng warning: iCCP: known incorrect sRGB profile
libpng warning: iCCP: known incorrect sRGB profile
process 1: D-Bus library appears to be incorrectly set up; failed to read machine uuid: UUID file '/etc/machine-id' should contain a hex string of length 32, not length 0, with no other text
See the manual page for dbus-uuidgen to correct this issue.
In the main
[events] {
    "rendertime": 0.043580055236816406,
    "method": "POST",
    "user-agent": "PostmanRuntime/7.3.0",
    "load": [
        0.12,
        0.05,
        0.01
    ],
    "status_code": 200,
    "fds": 16,
    "timestamp": 1539298202,
    "path": "/execute",
    "active": 0,
    "qsize": 0,
    "args": {
        "posted_json": {
            "password": "Sup3rSaf3",
            "email": "test123@email.com"
        },
        "lua_source": "function main(splash)\n\tprint('In the main')\nend",
        "uid": 140536347530744
    },
    "maxrss": 90304,
    "_id": 140536347530744
}
[11/Oct/2018:22:50:01 +0000] "POST /execute HTTP/1.1" 200 - "-" "PostmanRuntime/7.3.0"

As you can clearly see it logs posted_json which contains our sensitive info (email, password, proxy configs, etc.) as well as lua_source which can also contain sensitive information.

As a solution I've added a command line arg that will disable the logging of these features.

Below is an example of the same code being posted to the endpoint with my changes in place

Log opened.
Splash version: 3.2
Qt 5.9.1, PyQt 5.9, WebKit 602.1, sip 4.19.3, Twisted 16.1.1, Lua 5.2
Python 3.5.2 (default, Nov 23 2017, 16:37:01) [GCC 5.4.0 20160609]
Open files limit: 1048576
Can't bump open files limit
Xvfb is started: ['Xvfb', ':1593578320', '-screen', '0', '1024x768x24', '-nolisten', 'tcp']
QStandardPaths: XDG_RUNTIME_DIR not set, defaulting to '/tmp/runtime-root'
proxy profiles support is enabled, proxy profiles path: /etc/splash/proxy-profiles
verbosity=1
slots=50
argument_cache_max_entries=500
Web UI: enabled, Lua: enabled (sandbox: enabled)
Server listening on 0.0.0.0:8050
Site starting on 8050
Starting factory <twisted.web.server.Site object at 0x7fb258b12a20>
libpng warning: iCCP: known incorrect sRGB profile
libpng warning: iCCP: known incorrect sRGB profile
process 1: D-Bus library appears to be incorrectly set up; failed to read machine uuid: UUID file '/etc/machine-id' should contain a hex string of length 32, not length 0, with no other text
See the manual page for dbus-uuidgen to correct this issue.
In the main
[events] {
    "args": {
        "uid": 140403968947704
    },
    "timestamp": 1539298443,
    "client_ip": "172.17.0.1",
    "fds": 16,
    "_id": 140403968947704,
    "status_code": 200,
    "rendertime": 0.03467202186584473,
    "path": "/execute",
    "method": "POST",
    "load": [
        0.08,
        0.07,
        0.01
    ],
    "active": 0,
    "user-agent": "PostmanRuntime/7.3.0",
    "qsize": 0,
    "maxrss": 90444
}
[11/Oct/2018:22:54:02 +0000] "POST /execute HTTP/1.1" 200 - "-" "PostmanRuntime/7.3.0"

As you can see, there's no lua_source or posted_json

Please feel free to comment on this PR and we can work together to get the feature wrapped into splash!

Thanks
Jack

[kmike]

Hi! I think it makes sense to have a way to prevent args from being put to logs. It is not only about security: if you're doing large crawls, and use lua scripts or cookies heavily, args may take a lot of disk space, and cause quite a lot of IO.

[kmike]

I don't think we should be hard-coding specific keys. I can see two ways of handling it:

1. dont_log argument, which can disable logging of specific fields per-request (posted_json and lua_source in this case);
2. --log-args 0 startup argument, which disables logging of args completely

[JackSeaton]

Yeah, I didn't think this was necessarily the best way to go about it. I was more so trying to get the idea out and we can go from there.

--log-args 0 would be great as long as it only stops the logging of this startup/shutdown args and not stops the logging from within the script (e.x. print())

[kmike]

I was thinking --log-args 0 disables logs only for Splash arguments, nothing else - i.e. "args" value in the log you've pasted