Specify mode rb on file reads

[AlanFoster]

Fixes an edge case when reading files on Windows, and fixes Ruby 3 crashes when reading files.

Windows fix

The file upload support of Meterpreter was broken on windows machines, which was doing additional EOL<->CRLF conversions on windows:

"b"  Binary file mode
     Suppresses EOL <-> CRLF conversion on Windows. And
     sets external encoding to ASCII-8BIT unless explicitly
     specified.

Crash fix

Ruby 2.7:

irb
2.7.1 :001 > RUBY_DESCRIPTION
 => "ruby 2.7.1p83 (2020-03-31 revision a0c7c23c9c) [x86_64-darwin18]" 
2.7.1 :003 > File.read('/etc/passwd', {:mode => 'rb'}).length
(irb):3: warning: Using the last argument as keyword parameters is deprecated
 => 7630 

Ruby 3:

/ # irb
irb(main):001:0> RUBY_DESCRIPTION
=> "ruby 3.0.1p64 (2021-04-05 revision 0fb782ee38) [x86_64-linux-musl]"
irb(main):002:0> File.read('/etc/passwd', {:mode => 'rb'}).length
(irb):2:in `read': no implicit conversion of Hash into Integer (TypeError)
	from (irb):2:in `<main>'
	from /usr/local/lib/ruby/gems/3.0.0/gems/irb-1.3.5/exe/irb:11:in `<top (required)>'
	from /usr/local/bin/irb:23:in `load'
	from /usr/local/bin/irb:23:in `<main>'

[timwr]

Looks good to me. I suspect some of these calls could be refactored to use the exploit_data function from file.rb, but I'll go ahead and land this for now to keep things simple and avoid needlessly breaking things.

[timwr]

Release notes

The change fixes the mode specification on File.read required for ruby 3 on multiple modules.