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Remove TODO comment for closed issue #2573

Merged
merged 10 commits into from
May 10, 2023
Merged

Remove TODO comment for closed issue #2573

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9861d72
verify message checksum
adetunjii May 1, 2023
a538e85
Merge branch 'main' of https://github.com/adetunjii/FerretDB
adetunjii May 4, 2023
6731573
Merge branch 'main' of https://github.com/FerretDB/FerretDB
adetunjii May 6, 2023
9b978c3
fix: removed todo tag for closed issue
adetunjii May 6, 2023
6cc8692
fix: removed todo tags for closed issues
adetunjii May 6, 2023
898adb9
fix: removed todo tags for closed issues
adetunjii May 6, 2023
e93b955
fix: linting error
adetunjii May 8, 2023
3dd46a6
Merge branch 'main' of https://github.com/FerretDB/FerretDB
adetunjii May 9, 2023
d43517d
Merge branch 'main' into main
AlekSi May 9, 2023
05d82b9
Merge branch 'FerretDB:main' into main
adetunjii May 9, 2023
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verify message checksum
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@adetunjii
adetunjii committed May 1, 2023
commit 9861d72afd0f56824ac57e4b1b261e5a50af678c
59 changes: 59 additions & 0 deletions internal/wire/msg_body.go
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Original file line number Diff line number Diff line change
Expand Up @@ -17,8 +17,10 @@ package wire
import (
"bufio"
"encoding"
"encoding/binary"
"errors"
"fmt"
"hash/crc32"
"io"

"github.com/FerretDB/FerretDB/internal/util/lazyerrors"
Expand All @@ -34,6 +36,9 @@ type MsgBody interface {
msgbody() // seal for go-sumtype
}

// crc32c checksum byte size
const kCrc32Size = 4

//go-sumtype:decl MsgBody

// ErrZeroRead is returned when zero bytes was read from connection,
Expand All @@ -44,6 +49,10 @@ var ErrZeroRead = errors.New("zero bytes read")
//
// Error is (possibly wrapped) ErrZeroRead if zero bytes was read.
func ReadMessage(r *bufio.Reader) (*MsgHeader, MsgBody, error) {
if err := verifyChecksum(r); err != nil {
return nil, nil, lazyerrors.Error(err)
}

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var header MsgHeader
if err := header.readFrom(r); err != nil {
return nil, nil, lazyerrors.Error(err)
Expand Down Expand Up @@ -123,3 +132,53 @@ func WriteMessage(w *bufio.Writer, header *MsgHeader, msg MsgBody) error {

return nil
}

// verifyChecksum verifies the checksum of the message it is attached
func verifyChecksum(r *bufio.Reader) error {
// n = MsgHeaderLen + flagbits length
n := MsgHeaderLen + 4
msgHeader, err := r.Peek(n)
if err != nil {
if err == io.EOF {
return ErrZeroRead
}

return lazyerrors.Error(err)
}

msgLen := int(binary.LittleEndian.Uint32(msgHeader[0:4]))

if msgLen < MsgHeaderLen || msgLen > MaxMsgLen {
return lazyerrors.Errorf("invalid message length %d", msgLen)
}

b, err := r.Peek(msgLen)
if err != nil {
return lazyerrors.Error(err)
}

flagbits := OpMsgFlags(binary.LittleEndian.Uint32(msgHeader[MsgHeaderLen:n]))
if flagbits.FlagSet(OpMsgChecksumPresent) {
// remove checksum from the message
actualMsg, checksum := detachChecksum(b)

if checksum != calculateChecksum(actualMsg) {
return lazyerrors.New("OP_MSG checksum does not match contents")
}
}

return nil
}

func detachChecksum(data []byte) ([]byte, uint32) {
msgLen := len(data)
msg := data[:msgLen-kCrc32Size]
checksum := binary.LittleEndian.Uint32(data[msgLen-kCrc32Size:])

return msg, checksum
}

func calculateChecksum(msg []byte) uint32 {
table := crc32.MakeTable(crc32.Castagnoli)
return crc32.Checksum(msg, table)
}