Git LFS support v2 (#122)

* Import github.com/git-lfs/lfs-test-server as lfs module base

Imported commit is 3968aac269a77b73924649b9412ae03f7ccd3198

Removed:

Dockerfile CONTRIBUTING.md mgmt* script/ vendor/ kvlogger.go
.dockerignore .gitignore README.md

* Remove config, add JWT support from github.com/mgit-at/lfs-test-server

Imported commit f0cdcc5a01599c5a955dc1bbf683bb4acecdba83

* Add LFS settings

* Add LFS meta object model

* Add LFS routes and initialization

* Import github.com/dgrijalva/jwt-go into vendor/

* Adapt LFS module: handlers, routing, meta store

* Move LFS routes to /user/repo/info/lfs/*

* Add request header checks to LFS BatchHandler / PostHandler

* Implement LFS basic authentication

* Rework JWT secret generation / load

* Implement LFS SSH token authentication with JWT

Specification: https://github.com/github/git-lfs/tree/master/docs/api

* Integrate LFS settings into install process

* Remove LFS objects when repository is deleted

Only removes objects from content store when deleted repo is the only
referencing repository

* Make LFS module stateless

Fixes bug where LFS would not work after installation without
restarting Gitea

* Change 500 'Internal Server Error' to 400 'Bad Request'

* Change sql query to xorm call

* Remove unneeded type from LFS module

* Change internal imports to code.gitea.io/gitea/

* Add Gitea authors copyright

* Change basic auth realm to "gitea-lfs"

* Add unique indexes to LFS model

* Use xorm count function in LFS check on repository delete

* Return io.ReadCloser from content store and close after usage

* Add LFS info to runWeb()

* Export LFS content store base path

* LFS file download from UI

* Work around git-lfs client issue with unauthenticated requests

Returning a dummy Authorization header for unauthenticated requests
lets git-lfs client skip asking for auth credentials
See: https://github.com/github/git-lfs/issues/1088

* Fix unauthenticated UI downloads from public repositories

* Authentication check order, Finish LFS file view logic

* Ignore LFS hooks if installed for current OS user

Fixes Gitea UI actions for repositories tracking LFS files.
Checks for minimum needed git version by parsing the semantic version
string.

* Hide LFS metafile diff from commit view, marking as binary

* Show LFS notice if file in commit view is tracked

* Add notbefore/nbf JWT claim

* Correct lint suggestions - comments for structs and functions

- Add comments to LFS model
- Function comment for GetRandomBytesAsBase64
- LFS server function comments and lint variable suggestion

* Move secret generation code out of conditional

Ensures no LFS code may run with an empty secret

* Do not hand out JWT tokens if LFS server support is disabled

vendor/github.com/dgrijalva/jwt-go/token.go

@@ -0,0 +1,108 @@
+package jwt
+
+import (
+	"encoding/base64"
+	"encoding/json"
+	"strings"
+	"time"
+)
+
+// TimeFunc provides the current time when parsing token to validate "exp" claim (expiration time).
+// You can override it to use another time value.  This is useful for testing or if your
+// server uses a different time zone than your tokens.
+var TimeFunc = time.Now
+
+// Parse methods use this callback function to supply
+// the key for verification.  The function receives the parsed,
+// but unverified Token.  This allows you to use properties in the
+// Header of the token (such as `kid`) to identify which key to use.
+type Keyfunc func(*Token) (interface{}, error)
+
+// A JWT Token.  Different fields will be used depending on whether you're
+// creating or parsing/verifying a token.
+type Token struct {
+	Raw       string                 // The raw token.  Populated when you Parse a token
+	Method    SigningMethod          // The signing method used or to be used
+	Header    map[string]interface{} // The first segment of the token
+	Claims    Claims                 // The second segment of the token
+	Signature string                 // The third segment of the token.  Populated when you Parse a token
+	Valid     bool                   // Is the token valid?  Populated when you Parse/Verify a token
+}
+
+// Create a new Token.  Takes a signing method
+func New(method SigningMethod) *Token {
+	return NewWithClaims(method, MapClaims{})
+}
+
+func NewWithClaims(method SigningMethod, claims Claims) *Token {
+	return &Token{
+		Header: map[string]interface{}{
+			"typ": "JWT",
+			"alg": method.Alg(),
+		},
+		Claims: claims,
+		Method: method,
+	}
+}
+
+// Get the complete, signed token
+func (t *Token) SignedString(key interface{}) (string, error) {
+	var sig, sstr string
+	var err error
+	if sstr, err = t.SigningString(); err != nil {
+		return "", err
+	}
+	if sig, err = t.Method.Sign(sstr, key); err != nil {
+		return "", err
+	}
+	return strings.Join([]string{sstr, sig}, "."), nil
+}
+
+// Generate the signing string.  This is the
+// most expensive part of the whole deal.  Unless you
+// need this for something special, just go straight for
+// the SignedString.
+func (t *Token) SigningString() (string, error) {
+	var err error
+	parts := make([]string, 2)
+	for i, _ := range parts {
+		var jsonValue []byte
+		if i == 0 {
+			if jsonValue, err = json.Marshal(t.Header); err != nil {
+				return "", err
+			}
+		} else {
+			if jsonValue, err = json.Marshal(t.Claims); err != nil {
+				return "", err
+			}
+		}
+
+		parts[i] = EncodeSegment(jsonValue)
+	}
+	return strings.Join(parts, "."), nil
+}
+
+// Parse, validate, and return a token.
+// keyFunc will receive the parsed token and should return the key for validating.
+// If everything is kosher, err will be nil
+func Parse(tokenString string, keyFunc Keyfunc) (*Token, error) {
+	return new(Parser).Parse(tokenString, keyFunc)
+}
+
+func ParseWithClaims(tokenString string, claims Claims, keyFunc Keyfunc) (*Token, error) {
+	return new(Parser).ParseWithClaims(tokenString, claims, keyFunc)
+}
+
+// Encode JWT specific base64url encoding with padding stripped
+func EncodeSegment(seg []byte) string {
+	return strings.TrimRight(base64.URLEncoding.EncodeToString(seg), "=")
+}
+
+// Decode JWT specific base64url encoding with padding stripped
+func DecodeSegment(seg string) ([]byte, error) {
+	if l := len(seg) % 4; l > 0 {
+		seg += strings.Repeat("=", 4-l)
+	}
+
+	return base64.URLEncoding.DecodeString(seg)
+}