frostfs-s3-gw/api/auth/center.go
Evgeniy Kulikov 0284bf136b Migrate to Credentials client
Signed-off-by: Evgeniy Kulikov <kim@nspcc.ru>
2020-11-24 12:17:36 +03:00

144 lines
3.8 KiB
Go

package auth
import (
"bytes"
"context"
"crypto/sha256"
"encoding/hex"
"fmt"
"io/ioutil"
"net/http"
"regexp"
"strings"
"time"
"github.com/aws/aws-sdk-go/aws/credentials"
v4 "github.com/aws/aws-sdk-go/aws/signer/v4"
sdk "github.com/nspcc-dev/cdn-neofs-sdk"
"github.com/nspcc-dev/cdn-neofs-sdk/creds/hcs"
"github.com/nspcc-dev/neofs-api-go/pkg/object"
"github.com/nspcc-dev/neofs-api-go/pkg/token"
"github.com/pkg/errors"
"go.uber.org/zap"
)
var authorizationFieldRegexp = regexp.MustCompile(`AWS4-HMAC-SHA256 Credential=(?P<access_key_id_cid>[^/]+)/(?P<access_key_id_oid>[^/]+)/(?P<date>[^/]+)/(?P<region>[^/]*)/(?P<service>[^/]+)/aws4_request,\s*SignedHeaders=(?P<signed_header_fields>.+),\s*Signature=(?P<v4_signature>.+)`)
type (
Center interface {
Authenticate(request *http.Request) (*token.BearerToken, error)
}
center struct {
cli sdk.Client
key hcs.PrivateKey
reg *regexpSubmatcher
}
Params struct {
Client sdk.Client
Logger *zap.Logger
Credential hcs.Credentials
}
)
// New creates an instance of AuthCenter.
func New(cli sdk.Client, key hcs.PrivateKey) Center {
return &center{
cli: cli,
key: key,
reg: &regexpSubmatcher{re: authorizationFieldRegexp},
}
}
func (c *center) Authenticate(r *http.Request) (*token.BearerToken, error) {
queryValues := r.URL.Query()
if queryValues.Get("X-Amz-Algorithm") == "AWS4-HMAC-SHA256" {
return nil, errors.New("pre-signed form of request is not supported")
}
authHeaderField := r.Header["Authorization"]
if len(authHeaderField) != 1 {
return nil, errors.New("unsupported request: wrong length of Authorization header field")
}
sms1 := c.reg.getSubmatches(authHeaderField[0])
if len(sms1) != 7 {
return nil, errors.New("bad Authorization header field")
}
signedHeaderFieldsNames := strings.Split(sms1["signed_header_fields"], ";")
if len(signedHeaderFieldsNames) == 0 {
return nil, errors.New("wrong format of signed headers part")
}
signatureDateTime, err := time.Parse("20060102T150405Z", r.Header.Get("X-Amz-Date"))
if err != nil {
return nil, errors.Wrap(err, "failed to parse x-amz-date header field")
}
accessKeyID := fmt.Sprintf("%s/%s", sms1["access_key_id_cid"], sms1["access_key_id_oid"])
address := object.NewAddress()
if err = address.Parse(accessKeyID); err != nil {
return nil, errors.Wrapf(err, "could not parse AccessBox address: %s", accessKeyID)
}
tkn, err := c.cli.Credentials().BearerToken(r.Context(), address, c.key)
if err != nil {
return nil, err
}
data, err := tkn.Marshal()
if err != nil {
return nil, err
}
hash := sha256.Sum256(data)
secret := hex.EncodeToString(hash[:])
otherRequest := r.Clone(context.TODO())
otherRequest.Header = map[string][]string{}
for hfn, hfvs := range r.Header {
for _, shfn := range signedHeaderFieldsNames {
if strings.EqualFold(hfn, shfn) {
otherRequest.Header[hfn] = hfvs
}
}
}
awsCreds := credentials.NewStaticCredentials(accessKeyID, secret, "")
signer := v4.NewSigner(awsCreds)
body, err := readAndKeepBody(r)
if err != nil {
return nil, errors.Wrap(err, "failed to read out request body")
}
hdr, err := signer.Sign(otherRequest, body, sms1["service"], sms1["region"], signatureDateTime)
if err != nil {
return nil, errors.Wrap(err, "failed to sign temporary HTTP request")
}
sms2 := c.reg.getSubmatches(hdr.Get("Authorization"))
if sms1["v4_signature"] != sms2["v4_signature"] {
return nil, errors.Wrap(err, "failed to pass authentication procedure")
}
return tkn, nil
}
// TODO: Make this write into a smart buffer backed by a file on a fast drive.
func readAndKeepBody(request *http.Request) (*bytes.Reader, error) {
if request.Body == nil {
var r bytes.Reader
return &r, nil
}
payload, err := ioutil.ReadAll(request.Body)
if err != nil {
return nil, err
}
request.Body = ioutil.NopCloser(bytes.NewReader(payload))
return bytes.NewReader(payload), nil
}