"Invalid char ':'" error when building with GO111MODULE=on

[deanishe]

Go v1.12.4 on macOS High Sierra.

When trying to build caddy v1.0.0-beta1 or master with GO111MODULE=on, go fails to extract this plugin due to colons in filenames:

go: extracting github.com/pyed/ipfilter v1.1.1
-> unzip /Users/username/pkg/mod/cache/download/github.com/pyed/ipfilter/@v/v1.1.1.zip: malformed file path "testdata/blacklist/1234/abcd/1234:abcd::1": invalid char ':'
build github.com/mholt/caddy/caddy: cannot load github.com/pyed/ipfilter: unzip /Users/username/pkg/mod/cache/download/github.com/pyed/ipfilter/@v/v1.1.1.zip: malformed file path "testdata/blacklist/1234/abcd/1234:abcd::1": invalid char ':'
2019/04/16 18:26:12 exit status 1
exit status 1

It seems the Go team do not plan to allow colons in filenames, as it's a reserved character on Windows.

[krader1961]

I can appreciate why a colon is a reserved character in MS Windows file names. It also has special meaning on other non-UNIX operating systems (many of which are of historical interest only). But looking at https://docs.microsoft.com/en-us/windows/desktop/fileio/naming-a-file#naming-conventions I'm left shaking my head in disbelief. They also disallow <, >, ?, and * and other characters in file names. WTF? Does Go also disallow those chars in module file names?

Regardless, we should probably rename those unit test support files and modify this module to support both colons and some other separator char for IPv6 addresses.

[krader1961]

Does anyone have an opinion on the optimal alternative separator char for IPv6 addresses? Underscore? Hyphen? Dollar-sign? Hash(sharp)-sign? Something else? I'd prefer not using periods due to ambiguity with IPv4 addresses.

[deanishe]

Does anyone have an opinion on the optimal alternative separator char for IPv6 addresses?

🍺, tbh.

But seriously, is confusion with IPv4 addresses likely?

That said, :: is common in IPv6 addresses, and .. isn't going to work at all in a filename.

[pyed]

We need to go with an alternative character, hyphens sounds okay .. I guess, any thoughts ?

[krader1961]

and .. isn't going to work at all in a filename

I can't speak for how MS Windows file APIs work but dots, even two consecutive dots, are valid in a UNIX file name. A double dot only has special significance when that is the entire file name.

is confusion with IPv4 addresses likely?

There isn't any ambiguity in practice but using periods does make it marginally harder for a human to tell at a glance whether it's an IPv4 or IPv6 address.

hyphens sounds okay .. I guess, any thoughts ?

It should be a char that doesn't have special-meaning when used in a shell bare word. So that rules out dollar-sign, hash-mark, etc. I'm leaning towards = for the symmetry with : but - is fine too.

[pyed]

2001=db8=a0b=12f0==1 OR 2001-dbz-a0b-12f0--1, I guess = looks more like : and - makes it look like a Mac address, so = it is.
Edit: MAC address uses : too 🤦‍♂️

[krader1961]

@pyed Do you want to take care of this or would you prefer I do so since I wrote the code in question?

[pyed]

@krader1961 I'd really appreciate it if you write the fix for this as you know your way around this part of the code better than I do.

[ghost]

@krader1961 Any estimate on when you'll open a PR to fix this issue? I can't build Caddy from source because of this problem.

[krader1961]

@whalehub I will try fix it this weekend; i.e., the next 48 hours. But I'll need to send a P.R. for review and that could take a couple more days before it is merged.

[ghost]

@krader1961 Thank you!

@pyed Can you please push a v1.1.2 release which includes this commit?

[deanishe]

I can't speak for how MS Windows file APIs work but dots, even two consecutive dots, are valid in a UNIX file name

Windows doesn't like filename ending in a dot. Yup, it's technically valid in UNIX filenames, but code to mitigate filesystem traversal vulns doesn't always know that and may reject any path with .. in it.

[ghost]

@pyed Thank you for the v1.1.2 release!