61 lines
1.6 KiB
Go
61 lines
1.6 KiB
Go
/*
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SSHSecure - a program to harden OpenSSH from defaults
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Copyright (C) 2020 Brent Saner
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <https://www.gnu.org/licenses/>.
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*/
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package moduli
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import (
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"bytes"
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"encoding/hex"
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"errors"
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"fmt"
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"net/http"
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"golang.org/x/crypto/sha3"
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)
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func getPregen() ([]byte, error) {
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// get the pregenerated moduli
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resp, err := http.Get(pregenURL)
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if err != nil {
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return nil, err
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}
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if resp.StatusCode != http.StatusOK {
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return nil, errors.New(fmt.Sprintf("returned status code %v: %v", resp.StatusCode, resp.Status))
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}
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defer resp.Body.Close()
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b := make([]byte, resp.ContentLength)
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if _, err = resp.Body.Read(b); err != nil {
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return nil, err
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}
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// and compare the SHA3-512 (NIST) checksum.
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s := sha3.New512()
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if _, err = s.Write(b); err != nil {
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// TODO: return nil instead of b?
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return b, err
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}
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goodCksum, err := hex.DecodeString(pregenCksum)
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if err != nil {
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return nil, err
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}
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// We just compare the bytestrings.
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if bytes.Compare(s.Sum(nil), goodCksum) != 0 {
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return nil, errors.New("checksums do not match")
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}
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return b, nil
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}
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