forked from sassoftware/relic
/
info.go
81 lines (74 loc) · 1.93 KB
/
info.go
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//
// Copyright (c) SAS Institute Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
package starman
import (
"archive/tar"
"errors"
"io"
"io/ioutil"
"strings"
"github.com/sassoftware/relic/lib/readercounter"
)
const (
mdPrefix = ".metadata/"
sigSuffix = ".sig"
padSuffix = ".pad"
blockSize = 512
)
type starmanInfo struct {
mdblob, sigblob []byte
sigStart, sigEnd int64
mdname string
md TarMD
hasSig bool
}
func verifyMeta(r io.Reader) (*starmanInfo, error) {
info := new(starmanInfo)
rc := readercounter.New(r)
tr := tar.NewReader(rc)
hdr, err := tr.Next()
if err != nil {
return nil, err
} else if !strings.HasPrefix(hdr.Name, mdPrefix) {
return nil, errors.New("unsupported archive format")
}
info.mdname = hdr.Name
info.mdblob, err = ioutil.ReadAll(tr)
if err != nil {
return nil, err
}
info.sigStart = (rc.N + blockSize - 1) / blockSize * blockSize
hdr, err = tr.Next()
if err != nil && err != io.EOF {
return nil, err
} else if hdr.Name == info.mdname+sigSuffix || hdr.Name == info.mdname+padSuffix {
// read existing signature
info.sigblob, err = ioutil.ReadAll(tr)
if err != nil {
return nil, err
}
if hdr.Name == info.mdname+sigSuffix {
info.hasSig = true
}
info.sigEnd = (rc.N + blockSize - 1) / blockSize * blockSize
} else {
info.sigEnd = info.sigStart
}
if err := info.verifyFiles(tr); err != nil {
return nil, err
}
return info, nil
}