89 lines
2.4 KiB
Go
89 lines
2.4 KiB
Go
// Copyright (c) 2024 Proton AG
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//
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// This file is part of Proton Mail Bridge.
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//
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// Proton Mail Bridge 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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//
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// Proton Mail Bridge 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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//
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// You should have received a copy of the GNU General Public License
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// along with Proton Mail Bridge. If not, see <https://www.gnu.org/licenses/>.
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package message
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import (
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"bytes"
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"encoding/base64"
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"io"
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"github.com/ProtonMail/go-proton-api"
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"github.com/ProtonMail/gopenpgp/v2/crypto"
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"github.com/pkg/errors"
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)
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type DecryptedAttachment struct {
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Packet []byte
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Encrypted []byte
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Data bytes.Buffer
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Err error
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}
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type DecryptedMessage struct {
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Msg proton.Message
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Body bytes.Buffer
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BodyErr error
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Attachments []DecryptedAttachment
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}
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var ErrInvalidAttachmentPacket = errors.New("invalid attachment packet")
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func DecryptMessage(kr *crypto.KeyRing, msg proton.Message, attData [][]byte) DecryptedMessage {
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result := DecryptedMessage{
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Msg: msg,
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}
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result.Body.Grow(len(msg.Body))
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if err := msg.DecryptInto(kr, &result.Body); err != nil {
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result.BodyErr = errors.Wrap(ErrDecryptionFailed, err.Error())
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}
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result.Attachments = make([]DecryptedAttachment, len(msg.Attachments))
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for i, attachment := range msg.Attachments {
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result.Attachments[i].Encrypted = attData[i]
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kps, err := base64.StdEncoding.DecodeString(attachment.KeyPackets)
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if err != nil {
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result.Attachments[i].Err = errors.Wrap(ErrInvalidAttachmentPacket, err.Error())
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continue
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}
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result.Attachments[i].Packet = kps
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// Use io.Multi
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attachmentReader := io.MultiReader(bytes.NewReader(kps), bytes.NewReader(attData[i]))
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stream, err := kr.DecryptStream(attachmentReader, nil, crypto.GetUnixTime())
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if err != nil {
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result.Attachments[i].Err = errors.Wrap(ErrDecryptionFailed, err.Error())
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continue
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}
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result.Attachments[i].Data.Grow(len(kps) + len(attData))
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if _, err := result.Attachments[i].Data.ReadFrom(stream); err != nil {
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result.Attachments[i].Err = errors.Wrap(ErrDecryptionFailed, err.Error())
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continue
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}
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}
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return result
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}
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