f06492430e
Go 1.12.8 introduces a security fix for parsing URLs that contain a colon followed by an invalid port number. Since our SSH remotes can contain just such a colon, our hack to make these into URLs no longer works. Fix this by replacing the first colon in these "URLs" with a slash, which is a path delimiter, which makes them parsable by newer versions of Go. Update the name of the function since it now does more than its previous name implies.
328 lines
10 KiB
Go
328 lines
10 KiB
Go
package lfsapi
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import (
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"encoding/base64"
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"fmt"
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"net/http"
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"net/url"
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"os"
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"strings"
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"github.com/git-lfs/git-lfs/creds"
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"github.com/git-lfs/git-lfs/errors"
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"github.com/git-lfs/git-lfs/lfshttp"
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"github.com/rubyist/tracerx"
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)
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var (
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defaultEndpointFinder = NewEndpointFinder(nil)
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)
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// DoWithAuth sends an HTTP request to get an HTTP response. It attempts to add
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// authentication from netrc or git's credential helpers if necessary,
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// supporting basic and ntlm authentication.
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func (c *Client) DoWithAuth(remote string, access Access, req *http.Request) (*http.Response, error) {
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res, err := c.doWithAuth(remote, access, req, nil)
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if errors.IsAuthError(err) {
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if len(req.Header.Get("Authorization")) == 0 {
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// This case represents a rejected request that
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// should have been authenticated but wasn't. Do
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// not count this against our redirection
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// maximum.
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newAccess := c.Endpoints.AccessFor(access.url)
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tracerx.Printf("api: http response indicates %q authentication. Resubmitting...", newAccess.Mode())
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return c.DoWithAuth(remote, newAccess, req)
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}
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}
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return res, err
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}
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// DoWithAuthNoRetry sends an HTTP request to get an HTTP response. It works in
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// the same way as DoWithAuth, but will not retry the request if it fails with
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// an authorization error.
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func (c *Client) DoWithAuthNoRetry(remote string, access Access, req *http.Request) (*http.Response, error) {
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return c.doWithAuth(remote, access, req, nil)
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}
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// DoAPIRequestWithAuth sends an HTTP request to get an HTTP response similarly
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// to DoWithAuth, but using the LFS API endpoint for the provided remote and
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// operation to determine the access mode.
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func (c *Client) DoAPIRequestWithAuth(remote string, req *http.Request) (*http.Response, error) {
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operation := getReqOperation(req)
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apiEndpoint := c.Endpoints.Endpoint(operation, remote)
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access := c.Endpoints.AccessFor(apiEndpoint.Url)
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return c.DoWithAuth(remote, access, req)
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}
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func (c *Client) doWithAuth(remote string, access Access, req *http.Request, via []*http.Request) (*http.Response, error) {
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req.Header = c.client.ExtraHeadersFor(req)
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credWrapper, err := c.getCreds(remote, access, req)
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if err != nil {
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return nil, err
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}
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res, err := c.doWithCreds(req, credWrapper, access, via)
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if err != nil {
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if errors.IsAuthError(err) {
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newAccess := access.Upgrade(getAuthAccess(res))
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if newAccess.Mode() != access.Mode() {
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c.Endpoints.SetAccess(newAccess)
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}
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if credWrapper.Creds != nil {
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req.Header.Del("Authorization")
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credWrapper.CredentialHelper.Reject(credWrapper.Creds)
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}
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}
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}
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if res != nil && res.StatusCode < 300 && res.StatusCode > 199 {
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credWrapper.CredentialHelper.Approve(credWrapper.Creds)
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}
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return res, err
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}
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func (c *Client) doWithCreds(req *http.Request, credWrapper creds.CredentialHelperWrapper, access Access, via []*http.Request) (*http.Response, error) {
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if access.Mode() == NTLMAccess {
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return c.doWithNTLM(req, credWrapper)
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}
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req.Header.Set("User-Agent", lfshttp.UserAgent)
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redirectedReq, res, err := c.client.DoWithRedirect(c.client.HttpClient(req.Host), req, "", via)
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if err != nil || res != nil {
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return res, err
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}
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if redirectedReq == nil {
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return res, errors.New("failed to redirect request")
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}
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return c.doWithAuth("", access, redirectedReq, via)
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}
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// getCreds fills the authorization header for the given request if possible,
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// from the following sources:
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//
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// 1. NTLM access is handled elsewhere.
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// 2. Existing Authorization or ?token query tells LFS that the request is ready.
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// 3. Netrc based on the hostname.
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// 4. URL authentication on the Endpoint URL or the Git Remote URL.
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// 5. Git Credential Helper, potentially prompting the user.
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//
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// There are three URLs in play, that make this a little confusing.
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//
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// 1. The request URL, which should be something like "https://git.com/repo.git/info/lfs/objects/batch"
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// 2. The LFS API URL, which should be something like "https://git.com/repo.git/info/lfs"
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// This URL used for the "lfs.URL.access" git config key, which determines
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// what kind of auth the LFS server expects. Could be BasicAccess, NTLMAccess,
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// or NoneAccess, in which the Git Credential Helper step is skipped. We do
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// not want to prompt the user for a password to fetch public repository data.
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// 3. The Git Remote URL, which should be something like "https://git.com/repo.git"
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// This URL is used for the Git Credential Helper. This way existing https
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// Git remote credentials can be re-used for LFS.
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func (c *Client) getCreds(remote string, access Access, req *http.Request) (creds.CredentialHelperWrapper, error) {
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ef := c.Endpoints
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if ef == nil {
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ef = defaultEndpointFinder
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}
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operation := getReqOperation(req)
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apiEndpoint := ef.Endpoint(operation, remote)
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if access.Mode() != NTLMAccess {
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if requestHasAuth(req) || access.Mode() == NoneAccess {
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return creds.CredentialHelperWrapper{CredentialHelper: creds.NullCreds, Input: nil, Url: nil, Creds: nil}, nil
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}
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credsURL, err := getCredURLForAPI(ef, operation, remote, apiEndpoint, req)
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if err != nil {
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return creds.CredentialHelperWrapper{CredentialHelper: creds.NullCreds, Input: nil, Url: nil, Creds: nil}, errors.Wrap(err, "creds")
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}
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if credsURL == nil {
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return creds.CredentialHelperWrapper{CredentialHelper: creds.NullCreds, Input: nil, Url: nil, Creds: nil}, nil
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}
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credWrapper := c.getGitCredsWrapper(ef, req, credsURL)
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err = credWrapper.FillCreds()
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if err == nil {
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tracerx.Printf("Filled credentials for %s", credsURL)
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setRequestAuth(req, credWrapper.Creds["username"], credWrapper.Creds["password"])
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}
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return credWrapper, err
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}
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// NTLM ONLY
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credsURL, err := url.Parse(apiEndpoint.Url)
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if err != nil {
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return creds.CredentialHelperWrapper{CredentialHelper: creds.NullCreds, Input: nil, Url: nil, Creds: nil}, errors.Wrap(err, "creds")
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}
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// NTLM uses creds to create the session
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credWrapper := c.getGitCredsWrapper(ef, req, credsURL)
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return credWrapper, err
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}
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func (c *Client) getGitCredsWrapper(ef EndpointFinder, req *http.Request, u *url.URL) creds.CredentialHelperWrapper {
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return c.credContext.GetCredentialHelper(c.Credentials, u)
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}
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func getCredURLForAPI(ef EndpointFinder, operation, remote string, apiEndpoint lfshttp.Endpoint, req *http.Request) (*url.URL, error) {
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apiURL, err := url.Parse(apiEndpoint.Url)
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if err != nil {
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return nil, err
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}
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// if the LFS request doesn't match the current LFS url, don't bother
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// attempting to set the Authorization header from the LFS or Git remote URLs.
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if req.URL.Scheme != apiURL.Scheme ||
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req.URL.Host != apiURL.Host {
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return req.URL, nil
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}
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if setRequestAuthFromURL(req, apiURL) {
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return nil, nil
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}
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if len(remote) > 0 {
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if u := ef.GitRemoteURL(remote, operation == "upload"); u != "" {
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schemedUrl, _ := fixSchemelessURL(u)
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gitRemoteURL, err := url.Parse(schemedUrl)
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if err != nil {
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return nil, err
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}
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if gitRemoteURL.Scheme == apiURL.Scheme &&
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gitRemoteURL.Host == apiURL.Host {
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if setRequestAuthFromURL(req, gitRemoteURL) {
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return nil, nil
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}
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return gitRemoteURL, nil
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}
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}
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}
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return apiURL, nil
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}
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// fixSchemelessURL prepends an empty scheme "//" if none was found in
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// the URL and replaces the first colon with a slash in order to satisfy RFC
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// 3986 §3.3, and `net/url.Parse()`.
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//
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// It returns a string parse-able with `net/url.Parse()` and a boolean whether
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// or not an empty scheme was added.
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func fixSchemelessURL(u string) (string, bool) {
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if hasScheme(u) {
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return u, false
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}
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colon := strings.Index(u, ":")
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slash := strings.Index(u, "/")
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if colon >= 0 && (slash < 0 || colon < slash) {
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// First path segment has a colon, assumed that it's a
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// scheme-less URL. Append an empty scheme on top to
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// satisfy RFC 3986 §3.3, and `net/url.Parse()`.
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//
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// In addition, replace the first colon with a slash since
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// otherwise the colon looks like it's introducing a port
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// number.
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return fmt.Sprintf("//%s", strings.Replace(u, ":", "/", 1)), true
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}
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return u, true
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}
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var (
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// supportedSchemes is the list of URL schemes the `lfsapi` package
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// supports.
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supportedSchemes = []string{"ssh", "http", "https"}
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)
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// hasScheme returns whether or not a given string (taken to represent a RFC
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// 3986 URL) has a scheme that is supported by the `lfsapi` package.
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func hasScheme(what string) bool {
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for _, scheme := range supportedSchemes {
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if strings.HasPrefix(what, fmt.Sprintf("%s://", scheme)) {
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return true
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}
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}
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return false
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}
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func requestHasAuth(req *http.Request) bool {
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// The "Authorization" string constant is safe, since we assume that all
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// request headers have been canonicalized.
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if len(req.Header.Get("Authorization")) > 0 {
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return true
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}
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return len(req.URL.Query().Get("token")) > 0
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}
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func setRequestAuthFromURL(req *http.Request, u *url.URL) bool {
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if u.User == nil {
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return false
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}
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if pass, ok := u.User.Password(); ok {
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fmt.Fprintln(os.Stderr, "warning: current Git remote contains credentials")
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setRequestAuth(req, u.User.Username(), pass)
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return true
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}
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return false
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}
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func setRequestAuth(req *http.Request, user, pass string) {
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// better not be NTLM!
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if len(user) == 0 && len(pass) == 0 {
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return
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}
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token := fmt.Sprintf("%s:%s", user, pass)
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auth := "Basic " + strings.TrimSpace(base64.StdEncoding.EncodeToString([]byte(token)))
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req.Header.Set("Authorization", auth)
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}
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func getReqOperation(req *http.Request) string {
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operation := "download"
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if req.Method == "POST" || req.Method == "PUT" {
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operation = "upload"
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}
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return operation
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}
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var (
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authenticateHeaders = []string{"Lfs-Authenticate", "Www-Authenticate"}
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)
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func getAuthAccess(res *http.Response) AccessMode {
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for _, headerName := range authenticateHeaders {
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for _, auth := range res.Header[headerName] {
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pieces := strings.SplitN(strings.ToLower(auth), " ", 2)
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if len(pieces) == 0 {
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continue
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}
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switch AccessMode(pieces[0]) {
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case NegotiateAccess, NTLMAccess:
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// When server sends Www-Authentication: Negotiate, it supports both Kerberos and NTLM.
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// Since git-lfs current does not support Kerberos, we will return NTLM in this case.
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return NTLMAccess
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}
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}
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}
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return BasicAccess
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}
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