cmd/go: define HTTP authentication extension mechanism

draftcode commented 6 years ago

NOTE: The accepted proposal is https://github.com/golang/go/issues/26232#issuecomment-461525141.

Problem

The custom import path mechanism (?go-get=1 and meta tag) works for public URLs, but it doesn't work for auth required URLs. This is because when go-get fetches the URL with ?go-get=1, it uses net/http.DefaultClient, and it doesn't know the credentials it needs to access the URL. A user cannot run go get against private source code hosting service because of this.

Goal

Make go get git.mycompany.com/private-repo work, where https://git.mycompany.com/private-repo requires authentication.

Idea 1 (credential helper)

Introduce a credential helper mechanism like git-credential-helpers. A user specifies a path to a binary via GOGET_CREDENTIAL_HELPER and go get executes that with the import path as an argument. The credential helper binary returns HTTP headers (like "Authorization: Basic blah\n", and go get adds these headers when it tries to fetch go-get=1 URLs.

PRO: Straightforward solution to the problem description.
CON: Supporting multiple credential helpers becomes complicated. Git's credential helper mechanism supports multiple credential helper, and Git runs each in order. This sometimes makes an unexpected behavior that is hard to debug.

Idea 2 (go-get helper)

Introduce a custom source code fetching mechanism. When go get needs to fetch the source code for the import path git.mycompany.com/private-repo, it looks for the binary go-get-git.mycompany.com based on the host name of the import path. When such binary exists in $PATH, it executes that binary with the import path and a destination in $GOPATH (for example, go-get-git.mycompany.com git.mycompany.com/private-repo $GOPATH/src/git.mycompany.com/private-repo). The binary is responsible for fetching the source code to the specified $GOPATH location.

PRO: As a side effect, this make go get work with VCSs other than git/hg/svn/bzr.
CON: I'm not sure how this works with go get -f or go get -insecure.

draftcode commented 6 years ago

rsc commented 6 years ago

The original vgo prototype just read $HOME/.netrc. I'd rather do something like that than shell out to a whole separate program.

draftcode commented 6 years ago

.netrc works for HTTP basic auth with unlimited lifetime credentials. But it doesn't work for other types, like:

OAuth2 access tokens. OAuth2 access tokens usually have a limited lifetime, and it needs to be issued dynamically. Because of this, this cannot be in a static file.
Cookie based auth. netrc as a format is not a format that represent an HTTP cookie. Alternatively, Netscape's cookie file format (the same format as .gitcookies) can be used. This cannot support dynamically generated credentials as well. We actually have Git repositories that are behind dynamically generated cookie-based auth at Google (BeyondCorp at Google: https://cloud.google.com/beyondcorp/).

rsc commented 6 years ago

Note that even "access denied" pages can have meta tags - go get does not require a 200 response, exactly for this kind of thing. So git.mycompany.com could serve the tags unauthenticated as one workaround.

Are there any more general "HTTP auth credential helpers" in the world besides git-credential-helper? How do other systems deal with this? If there's something standard to hook into (like .netrc) then that's better than designing our own.

draftcode commented 6 years ago

If the access denied page contains the meta tag, it can be used as a prober. Let's say git.mycompany.com has an not-yet announced new product, collaborating with another company other-tech-company.com, and they host a Git repository at git.mycompany.com/ng-product/collab-other-tech-company. An attacker can probe if a repository exists by looking at the go-get's meta tag, and they can learn mycompany.com will have a business relationship other-tech-company.com to create a new product (and maybe benefit from this insider info).

As far as I know, there's no generic mechanism that majority of people use for storing and obtaining credentials through API. The closest thing I can think of is ssh-agent. Or if it's OS X, OS X Keychain.

rsc commented 6 years ago

It's only a prober if you check that the thing exists before serving the meta-tag.

$ curl 'https://rsc.io/asdgihopajdfklgadfglhifsdfj?go-get=1'
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
<meta name="go-import" content="rsc.io/asdgihopajdfklgadfglhifsdfj git https://github.com/rsc/asdgihopajdfklgadfglhifsdfj">
<meta http-equiv="refresh" content="0; url=https://godoc.org/rsc.io/asdgihopajdfklgadfglhifsdfj">
</head>
<body>
Redirecting to docs at <a href="https://godoc.org/rsc.io/asdgihopajdfklgadfglhifsdfj">godoc.org/rsc.io/asdgihopajdfklgadfglhifsdfj</a>...
</body>
</html>
r$

rsc commented 6 years ago

Clearly we could use a better idea here but I'd like to have just one thing that's standard instead of inventing our own (that is, I want something like .netrc).

draftcode commented 6 years ago

It's only a prober if you check that the thing exists before serving the meta-tag.

I cannot interpret this. The problem is that an attacker can use this to extract the repository existence by using this meta-tag. If the page checks if the repository exists and change the response, it can be used as a prober.

rsc commented 6 years ago

If the page checks if the repository exists and change the response, it can be used as a prober.

Then don't check, and don't change the response.

bradfitz commented 6 years ago

Are there any more general "HTTP auth credential helpers" in the world besides git-credential-helper?

https://docs.docker.com/engine/reference/commandline/login/#credentials-store

https://github.com/GoogleCloudPlatform/docker-credential-gcr

draftcode commented 6 years ago

Then don't check, and don't change the response.

So the page should not do any auth, and should not contain meta tag? I thought you're suggesting to add a meta tag and in the next response you're saying not to add meta tag?

draftcode commented 6 years ago

An example leakage: https://play.golang.org/p/rCYzVWQSQni

We want to avoid this. By adding a meta-tag to the response as rsc suggests, the repository existence is leaked.

bradfitz commented 6 years ago

@draftcode, I assumed what was meant as you should advertise it for all URLs, including /android/device/g000gle/foo-bar-not-exist , regardless of whether it actually exists.

draftcode commented 6 years ago

I assumed what was meant as you should advertise it for all URLs, including /android/device/g000gle/foo-bar-not-exist , regardless of whether it actually exists.

Note that the third part in meta tag should be a git repository URL. This means, if a repository exists, the third part should be a valid Git repository path. In the example, I used example.com/android/device/google/marlin-kernel/foo/bar as an example package path. The valid meta tag for this is <meta name="go-import" content="example.com git http://example.com/android/device/google/marlin-kernel">, not <meta name="go-import" content="example.com git http://example.com/android/device/google/marlin-kernel/foo/bar">. Because of this, I can tell whether a repository exists by adding paths that wouldn't exist. When I make a request, if meta tag's returned path is modified, it means the repository exists.

draftcode commented 6 years ago

An example that for this: https://play.golang.org/p/OWb6zRUD02r

rsc commented 6 years ago

@draftcode I am saying that if you pick a trivial rule like "example.com/x/y/z/w redirects to the repo at git.example.com/x/y", then you can implement it with no Auth check and no repo validity check, so that it responds to any possible x/y/z/w with the same answer. Then there is no leakage. That was the point of my curl example above: there is no actual package at rsc.io/asdgihopajdfklgadfglhifsdfj but the curl still reads back meta tags for it.

If you need example.com/x/y/z/w to redirect to different git servers based on the exact values of x,y,z,w then that's more difficult of course and leakage is hard to avoid.

This is all just a suggested workaround. What I'd really like is to find out about some plausibly general (not git-specific, not docker-specific) semi-standard way to interact with credential helpers. Maybe none exists and we have to come up with something. But that would be my last choice.

draftcode commented 6 years ago

If you need example.com/x/y/z/w to redirect to different git servers based on the exact values of x,y,z,w then that's more difficult of course and leakage is hard to avoid.

OK. We've considered that option when we investigated how GitHub deals with this, and found out that GitHub won't allow slashes in a repository name, so they can do what you've said. We cannot do that, so filed this bug.

What I'd really like is to find out about some plausibly general (not git-specific, not docker-specific) semi-standard way to interact with credential helpers. Maybe none exists and we have to come up with something. But that would be my last choice.

So far, I've shown what Git does for a similar problem. @bradfitz showed what Docker and GCP does for a similar problem (ADC now works only for service accounts, so it's a bit different). If there's a some standard way to get a cred, considering the size of these tools' community, there should be some implementation of that, but it seems there's no such thing. In fact, Docker created a credential helper mechanism following what Git did. From these, such standard, if exists, is something that Git and Docker communities at least are not aware of and are not using. @rsc, @bradfitz, and I are also not aware of such generic way that would be called as "semi-standard", it seems.

rsc commented 6 years ago

Given that there doesn't seem to be an agreed-upon standard, I guess the next step is for someone to propose a design that Go should use. I looked at git credential helpers but stopped looking when I saw bash snippets.

draftcode commented 6 years ago

Questions on the requirements:

My impression is that @rsc strongly prefers using a file instead of executing a command and using stdin/stdout. Is this a hard requirement?
- If this is a requirement, this means that Go cannot support OS-standard credential management mechanisms.
- Also this makes it hard to protect credentials. If this is done in stdin/stdout, the credential manager side can do a necessary re-auth.
This is just "defining a protocol between Go's toolchain and a user-defined credential manager", right? We do not want to create a password manager like LastPass for this purpose.
With a user-defined credential manager, users should be able to:
- Add an HTTP header (including cookies)
- Add an SSL client certificate
- Anything else?

josharian commented 6 years ago

My impression is that @rsc strongly prefers using a file instead of executing a command and using stdin/stdout. Is this a hard requirement?

He objected to bash snippets. It is possible (I do not know) that executing a binary rather than a shell might sit better with him.

If it were indeed command execution (a la EDITOR), then e.g. those of us who use 1password could use their command line support. I think macOS keychain has similar support.

rsc commented 5 years ago

Command-line execution seems necessary, since you want to lock things down and give cmd/go access to just one password, not your whole password set. Josh, what did you have in mind? Want to propose a starting point design?

dmitris commented 5 years ago

It would be great if we could achieve the stated above goal ("Make go get git.mycompany.com/private-repo work, where https://git.mycompany.com/private-repo requires authentication") without forcing the users to perform custom modifications to their ~/.netrc or ~/.gitconfig files (or installing extra binaries) - at least in the (I believe) common cases of GitHub [Enterprise] with SSH authentication (from the ssh agent).

Assuming the server returns a meta tag such as <meta name="go-import" content="git.mycompany.com/org/repo git https://git.mycompany.com/org/repo.git">, could the go tool try the following:

shell out git ls-remote -q https://git.mycompany.com/org/repo.git first (as now)
if it gets a response with an auth prompt: Username for 'https://git.mycompany.com':, try next the command with the corresponding ssh URL: git ls-remote -q ssh://git@git.mycompany.com/org/repo.git - and if it works, remember / cache that protocol for other git operations with the server (at least, within the same go invocation). (The git user must be standard for GitHub as it is indicated on https://help.github.com/articles/testing-your-ssh-connection/ and https://help.github.com/enterprise/2.14/user/articles/testing-your-ssh-connection/). This "retrial" step can be limited to the cases where server replies with Server: Github.com HTTP header ([1], [2]).

I believe this would make possible to use git with the SSH auth without having everyone to add the insteadOf stanzas in ~/.gitconfig on every server / VM or putting passwords in ~/.netrc etc. (To avoid this, we currently have to use a redirect server on an equivalent of go.mycompany.com that sends back <meta name="go-import" content="git.mycompany.com/org/repo git ssh://git@git.mycompany.com/org/repo"> - but it would be so nice to be able to use the "natural" git.mycompany.com/org/repo as imports / package names instead of go.mycompany.com and forcing everyone to learn and use the git.mycompany.com => go.mycompany.com replacement!) Having all Go users in the company to install an additional binary to bridge go and auth secrets would IMO be even more cumbersome (and the security team will likely consider it as yet another thing to worry about...).

I think it is an incredible strength of the Go tool that you can install and use it "right out of the box" - would love to see that feature and stellar user experience preserved and extended! 😄

[1] https://go-review.googlesource.com/c/go/+/33171 (abandoned; issue https://golang.org/issue/17898) [2] Russ's comment - https://github.com/golang/go/issues/24076#issuecomment-377562501

draftcode commented 5 years ago

Assuming the server returns a meta tag

@dmitris This proposal is for the servers that cannot return meta tags without an auth (see https://github.com/golang/go/issues/26232#issuecomment-412958321). It seems to me that your problem is not related to this.

rsc commented 5 years ago

@bcmills we should probably make this a Go 1.13 early.

bcmills commented 5 years ago

OAuth2 access tokens usually have a limited lifetime, and it needs to be issued dynamically. Because of this, this cannot be in a static file.

Heroku takes an interesting approach to that: their CLI obtains a fresh OAuth2 token and writes it to the user's .netrc file.

bcmills commented 5 years ago

@dmitris, if the user is able to contact the private HTTPS server, and the server knows that the repo is also private, why couldn't it provide an ssh:// URL in the <meta> tag (instead of an https:// URL) itself?

dmitris commented 5 years ago

@bcmills yes that works. Actually the modern GHE provides the Go meta tags "natively" so we were able to switch to git.xyzcompany.com imports and shut down the go.xyzcompany.com redirect server. My only gripe now is that go seems to prefer https:// git URLs + "personal access tokens" (as in https://help.github.com/articles/creating-a-personal-access-token-for-the-command-line/) while the standard at our company is the SSH authentication and git@git.xyzcompany.com URLs, so everyone has to add the insteadOf incantation in ~/.gitconfig in every environment / VM. To make clear - I'm not blaming Go at all, GitHub itself says cloning with HTTPs is recommended on https://help.github.com/articles/which-remote-url-should-i-use/ - so it is a reasonable pick. I still wish go would try both and use whichever one works so that we could run go install or go get without stumbling on the missing insteadOf config...

I have a tangential question: is it possible to pass to the go tool a client TLS certificate + key + CAcert (in environment variables or otherwise)? It could be useful in environments that take Zero Trust Networking seriously and where go tool needs to talk to the other side (the replace targets) that lives in a public cloud using mutual TLS for authN/Z. (This is hypothetical - we haven't yet had that requirement specifically for go, but mTLS is standard/required for communicating with the clouds)

bcmills commented 5 years ago

SSH vs. HTTPS for GitHub in particular is tracked in #26134.

I'm not sure about mTLS — please file that separately.

bcmills commented 5 years ago

Here is my proposed design for Go 1.13.

Design

A new environment variable, GOAUTH, will contain a list of authenticator commands to invoke: each command is a space-separated argument list, and the commands themselves are separated by semicolons.

The go command will maintain, in memory, a cache of credentials produced by GOAUTH invocations, and use them for both go-import resolution and the HTTPS module proxy protocol.

Before the first HTTPS fetch, the go command will invoke each GOAUTH command in the list with no additional arguments and no input. The GOAUTH command may reply with zero or more credentials to cache, written to stdout in this format:

one per line, one or more URL prefixes to which the credential should apply, beginning with the string https:// and ending at a complete path element.
an empty line
one per line, zero or more request headers to set to apply the credential
another empty line.

For each URL to be fetched, the go command will check the credential cache and apply the first matching credential from the command that appears earliest in the list, appending the corresponding headers to its own request headers (if any).

If the server responds with any 4xx code and the response body does not satisfy the request (for example, by including a valid <meta name="go-import"> tag), the go command will invoke the GOAUTH commands again, this time with the URL as an additional command-line argument. The go command will also write the following to the programs' stdin:

the protocol and status from the response
the response headers as parsed by the net/http package
an empty line.

(Note that, at least for HTTP 1.1, the contents written to stdin can be parsed verbatim as an HTTP HEAD response.)

Each GOAUTH command may reply with credentials as before, and those credentials take precedence over any previous credentials from that command for that prefix. (A non-empty list of prefixes followed by an empty list of request headers removes the previous credentials.) If none of the credentials in the replies match the request, the go command fails the fetch.

The go command will then retry the fetch with the updated credential for the URL. If the server responds with an error again, the fetch fails: a URL-specific GOAUTH will only be attempted once per fetch. The go command will recognize three builtin GOAUTH commands: off, netrc, and git. The netrc implementation will be equivalent to the go command's existing .netrc file support. The git implementation will use git credential fill. The default value of GOAUTH (if not set in the environment) will be netrc, preserving the credential behavior from Go 1.12.

Rationale

This approach provides very wide latitude for the authentication mechanism, while keeping the protocol close to HTTP itself. (The implementation for git credential is straightforward, and .netrc and cookies.txt should be similar.)

The initial calls to the GOAUTH programs reduce overhead from repeated command invocations (and latency from initial credential misses), while the secondary calls allow the programs to respond intelligently to authentication hints from the server (such as WWW-Authenticate types and realms).

Example exchange

Command:

$GOAUTH https://github.com/bcmills/private-repo

Input to GOAUTH:

HTTP/1.1 404 Not Found
Cache-Control: no-cache
Content-Security-Policy: default-src 'none'; base-uri 'self'; connect-src 'self'; form-action 'self'; img-src 'self' data:; script-src 'self'; style-src 'unsafe-inline'
Content-Type: text/html; charset=utf-8
Date: Wed, 06 Feb 2019 22:47:12 GMT
Expect-Ct: max-age=2592000, report-uri="https://api.github.com/_private/browser/errors"
Referrer-Policy: origin-when-cross-origin, strict-origin-when-cross-origin
Server: GitHub.com
Set-Cookie: has_recent_activity=1; path=/; expires=Wed, 06 Feb 2019 23:47:12 -0000
Set-Cookie: _gh_sess=ZWdxekI4RlFHbS82MEl5djZwcWNrRHJqdzhUNDlpTFM4aVFOa2E2TDRRTWFuZkhJenBDdmVYc24rYXBFZXJOTHN3VGdTZnc2RGVpYndmdTJCVFVTeE4zaTRkbHR0ZHYrODJLQTdqR1llaFQrVklQSk9YSWw2b3lROWxleENtL0ItLUJ2MGs1TnhuTnVPMTBpdXRIcUFSVmc9PQ%3D%3D--47220df4045034db9d8ce85c771e0d20341b29c0; path=/; secure; HttpOnly
Status: 404 Not Found
Strict-Transport-Security: max-age=31536000; includeSubdomains; preload
Vary: X-PJAX
X-Content-Type-Options: nosniff
X-Frame-Options: deny
X-Github-Request-Id: CE63:55B5:2AF684:48FB29:5C5B63F0
X-Request-Id: 8c810f80-9be4-48d9-b8c4-9a31b56aa312
X-Xss-Protection: 1; mode=block

Output from GOAUTH:

https://github.com

Authorization: Basic YWxhZGRpbjpvcGVuc2VzYW1l

(Note: the credential above is aladdin:opensesame, the standard example username and password for HTTPS auth protocols. Please be careful not to paste real credentials!)

gopherbot commented 5 years ago

Change https://golang.org/cl/161698 mentions this issue: cmd/go/internal/web2: make netrc parsing more robust

gopherbot commented 5 years ago

Change https://golang.org/cl/161666 mentions this issue: cmd/auth/authtest: add a manual-test harness for GOAUTH implementations

gopherbot commented 5 years ago

Change https://golang.org/cl/161667 mentions this issue: cmd/auth/gitauth: add a reference GOAUTH implementation using 'git credential fill'

gopherbot commented 5 years ago

Change https://golang.org/cl/161668 mentions this issue: cmd/auth/netrcauth: add a reference GOAUTH implementation using .netrc files

gopherbot commented 5 years ago

Change https://golang.org/cl/161669 mentions this issue: cmd/auth/cookieauth: add a GOAUTH implementation that reads from a cookiefile

rsc commented 5 years ago

I talked with @bcmills about his proposed solution, and it seems worth trying. Does anyone object to accepting this?

myitcv commented 5 years ago

@bcmills @rsc - looks great, just a couple of questions:

Many people who have hit auth-related issues thus far use git over ssh. Am I right in concluding that for these people their lot will not improve, i.e. they will still need to use either a .netrc file or a credential helper?
Is there any harm in making the default value of GOAUTH for 1.13 netrc;git? For those people (and selfishly I count myself amongst them) who have a git credential helper set, this will save setting another global environment variable. And in any case I'm guessing using a git credential helper is the direction in which we want to be pushing people?

bcmills commented 5 years ago

Many people who have hit auth-related issues thus far use git over ssh. Am I right in concluding that for these people their lot will not improve […]?

The main git-over-ssh use-case is #26134, which we should address separately.

In general, if a repo cannot be accessed via HTTPS at all, then its <meta name="go-import" […]> tag should provide an appropriate ssh:// URL.

We can probably provide some sort of automatic fallback for the hard-coded hosting services, but in general if we receive an HTTPS URL we don't know what username to try for ssh, even if we could infer the rest of the path.

We may want to allow the go-import tag to list multiple alternative URLs (for example, on https:// and one ssh://), but if we do that we'll have to be very careful not to break the existing parsers with it.

bcmills commented 5 years ago

Is there any harm in making the default value of GOAUTH for [1.13] netrc;git?

git credential fill is aggressively interactive, so that could jam up folks' CI configurations and generally mess with scripting. In contrast, we can look for a .netrc file without any user interaction whatsoever.

I'd like to keep the default non-interactive if we can.

myitcv commented 5 years ago

Thanks, all makes sense now.

In general, if a repo cannot be accessed via HTTPS at all, then its <meta name="go-import" […]> tag should provide an appropriate ssh:// URL.

Right so in the main (?) scenario, we're assuming that the initial ?go-get=1 request will be unauthenticated.

Is it documented anywhere that a go-import meta tag can supply an ssh:// URL?

https://tip.golang.org/cmd/go/#hdr-Remote_import_paths

Or are you saying this is how that use case will be solved in future?

git credential fill is aggressively interactive

Presumably the interactive mode is some sort of fallback; I'm guessing from your response it's not possible to tell git not to use that fallback.

bcmills commented 5 years ago

Presumably the interactive mode is some sort of fallback; I'm guessing from your response it's not possible to tell git not to use that fallback.

Correct. To be precise, if $GIT_ASKPASS or $SSH_ASKPASS fails to return a credential, git credential fill will look for (and open) /dev/tty and issue a password prompt itself.

That's the right thing to do if the user actually wants to type it a password (that is, if the go command itself is invoked interactively), but totally wrong in a CI or IDE context.

bcmills commented 5 years ago

Is it documented anywhere that a go-import meta tag can supply an ssh:// URL?

I don't think we give an example of it, but if that doesn't work today, then I will make it work. 😤

draftcode commented 5 years ago

The GOAUTH command may reply with zero or more credentials to cache, written to stdout in this format:

I want to check if I understand this correctly. GOAUTH may reply multiple sets of the credentials. The response format is:

RESPONSE ::= CREDENTIAL_SET*
CREDENTIAL_SET ::= (URL NEWLINE)+ NEWLINE (HEADER NEWLINE)* NEWLINE
URL ::= /* URL that starts with "https://" */
NEWLINE ::= '\n'
HEADER ::= /* HTTP header */

mortyccp commented 5 years ago

Right so in the main (?) scenario, we're assuming that the initial ?go-get=1 request will be unauthenticated.

FYI, gitlab need authentication for private repos in nested sub-group. So I think the initial ?go-get=1 request need to support authentication too.

bcmills commented 5 years ago

@myitcv

Right so in the main (?) scenario, we're assuming that the initial ?go-get=1 request will be unauthenticated.

Not necessarily. The protocol in this proposal would apply to both the initial ?go-get=1 fetch, any subsequent requests that use the mod protocol, and any HTTPS traffic to the configured GOPROXY server.

(When using VCS tools for direct fetches, it's still up to those individual tools to decide how to authenticate their own internal HTTPS traffic, if any.)

palsivertsen commented 5 years ago

Aren't we reinventing the wheel here? I not sure which other VCS's are supported/used by go get, but in the case of git, authentication is built in for both HTTP and SSH transports. For HTTP there's gitcredentials and for SSH there's ssh_config(5). git also supports other protocols but I think it's safe to say that they are outside scope. I'm sure other VCS's have similar approaches.

If we leave authentication to the VCS, the go tool chain only needs to instruct the VCS which url to use and make this configurable by the user.

Example

Make go consult a config file before downloading a dependency. The file should contain a mapping between import paths and the url passed to the VCS. E.g:

example.com/foo/bar git@example.com:foo/bar.git

As a side effect this also allows uses of simple proxies.

bcmills commented 5 years ago

@palsivertsen, the go tool does not make every HTTPS request through a VCS tool. This proposal is specifically for the requests that are not made through a VCS.

Note that git credential fill is one of the supported credential sources under this proposal: if you want to use it, you will be able to set GOAUTH=git and won't need to write any additional configuration files.

gopherbot commented 5 years ago

Change https://golang.org/cl/170581 mentions this issue: vcs-test/vcweb: add a handler that requires HTTPS Basic Auth

palsivertsen commented 5 years ago

@bcmills Which calls does the go tool need to make calls outside a VCS tool?

Maybe this is the wrong issue, but I'm trying to find a solution for when the following is true for a dependency:

Requires authentication
Host will deny any existence of resource unless request is authenticated
Authenticating HTTP requests is not an option (2FA / weak passwords)

I came here from #29094 which is a symptom of the above case. There are a lot of similar issues like this and so far I've found only one workaround which involves renaming the dependency and tricking the go tool into using ssh.

bcmills commented 5 years ago

Which calls does the go tool need to make calls outside a VCS tool?

It makes https://[…]?go-get=1 requests to resolve paths to repos (using go-import meta tags), and if the go-import tag indicates mod then it uses HTTPS to fetch the resulting modules (using the protocol described in https://tip.golang.org/cmd/go/#hdr-Module_proxy_protocol).

bcmills commented 5 years ago

I'm trying to find a solution for when the following is true for a dependency:

Requires authentication

Host will deny any existence of resource unless request is authenticated

Authenticating HTTP requests is not an option (2FA / weak passwords)

You only get to pick two of those: “requires authentication” and “authenticating […] is not an option” are mutually exclusive.

But note that the protocol described in https://github.com/golang/go/issues/26232#issuecomment-461525141 allows the GOAUTH plugin to do whatever it needs to do to authenticate — including interacting with the user to obtain 2FA credentials — as long as it can encode the result as a URL prefix and a set of HTTP request headers.

golang / go