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⚙️ Some refactoring.
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@Mihara
Mihara committed Jun 25, 2023
1 parent 6b54a67 commit a63209d
Showing 1 changed file with 39 additions and 27 deletions.
66 changes: 39 additions & 27 deletions main.go
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Original file line number Diff line number Diff line change
Expand Up @@ -146,12 +146,16 @@ func certInList(a []*x509.Certificate, x *x509.Certificate) bool {
return false
}

func check(e error, message string) {
func check(e error, message any) {
if e != nil {
l.Fatal(message, " ", e)
l.Fatal("ERROR: ", message, " ", e)
}
}

func die(message ...any) {
l.Fatal("ERROR: ", message)
}

func getCallsign(c x509.Certificate) string {
// This is how LoTW certificates encode callsign, I have no idea why.
callsign := ""
Expand Down Expand Up @@ -179,11 +183,11 @@ func saveFile(filename string, fileData []byte) {
if filename != "" {
if filename == "=" {
if _, err := os.Stdout.Write(fileData); err != nil {
l.Fatal("Error while saving a file:", err)
die("Error while saving a file:", err)
}
} else {
if err := os.WriteFile(filename, fileData, 0666); err != nil {
l.Fatal("Error while saving a file:", err)
die("Error while saving a file:", err)
}
}
}
Expand Down Expand Up @@ -240,7 +244,7 @@ func normalizeTextString(text string) string {

var textLines []string
for _, l := range strings.Split(replacer.Replace(text), replacement) {
textLines = append(textLines, strings.Trim(l, " \t"))
textLines = append(textLines, strings.TrimSpace(l))
}

// All preceding empty lines and all tailing empty lines must be ignored when signing as well.
Expand Down Expand Up @@ -337,15 +341,15 @@ func main() {
check(err, "Could not make sense of the key file.")

if time.Now().After(cert.NotAfter) {
l.Fatal("Cannot use a LoTW certificate beyond its expiry time.")
die("Cannot use a LoTW certificate beyond its expiry time.")
}
if time.Now().Before(cert.NotBefore) {
l.Fatal("Cannot use a LoTW certificate before it goes active.")
die("Cannot use a LoTW certificate before it goes active.")
}

callsign := getCallsign(*cert)
if callsign == "" {
l.Fatal("The signing key does not appear to be a LoTW key.")
die("The signing key does not appear to be a LoTW key.")
}

// Slurp the input file...
Expand Down Expand Up @@ -374,7 +378,7 @@ func main() {
hashed[:],
)
default:
l.Fatal("You have discovered a LoTW key of a previously unseen, unsupported type! Please email me about it.")
die("You have discovered a LoTW key of a previously unseen, unsupported type! Please email me about it.")
}
check(err, "Signing failure, something weird happened.")

Expand Down Expand Up @@ -464,18 +468,18 @@ func main() {
textData := string(fileData)
rawTextHeader, restText, found = strings.Cut(textData, textModeHeader)
if !found {
l.Fatal("The file does not appear to be signed in text mode.")
die("The file does not appear to be signed in text mode.")
}

tailEnd := strings.LastIndex(restText, textModeFooter)
if tailEnd < 0 {
l.Fatal("Signed message seems to have lost a chunk.")
die("Signed message seems to have lost a chunk.")
}
signedText := restText[:tailEnd]

postSig := strings.LastIndex(restText, textModeEnding)
if postSig < 0 {
l.Fatal("Signed message appears to be missing parts of the signature.")
die("Signed message appears to be missing parts of the signature.")
}

rawTextFooter = restText[postSig+len(textModeEnding):]
Expand All @@ -485,7 +489,7 @@ func main() {
// So we normalize the restText before feeding it into the decoder.
block, _ := pem.Decode([]byte(normalizeTextString(restText)))
if block == nil || block.Type != textModeSigPem {
l.Fatal("Signature not found.")
die("Signature not found.")
}

sigBlock, err = uncompress(block.Bytes)
Expand All @@ -494,7 +498,7 @@ func main() {
} else {
sigStart := bytes.LastIndex(fileData, []byte(sigHeader))
if sigStart < 0 {
l.Fatal("Broken or missing signature block.")
die("Broken or missing signature block.")
}
sigBlock = fileData[sigStart:]
fileData = fileData[:sigStart]
Expand All @@ -507,7 +511,7 @@ func main() {
var sigData SigBlock
if !textMode {
if !bytes.Equal(sigBlock[:len(sigHeader)], []byte(sigHeader)) {
l.Fatal("Could not find signature in file.")
die("Could not find signature in file.")
}
sigBlock = sigBlock[len(sigHeader):]
// While we're at it, try to uncompress sig block.
Expand All @@ -528,13 +532,13 @@ func main() {
check(err, "Broken version number in signature block.")

if myVersion.Compare(sigVersion) < 0 {
l.Fatal("File is signed with a newer version of lotw-trust than v", myVersion)
die("File is signed with a newer version of lotw-trust than v", myVersion)
}

if myVersion.Compare(sigVersion) > 0 {
oldVersion, _ := semver.Parse(minSupportedVersion)
if sigVersion.Compare(oldVersion) < 0 {
l.Fatal("Cannot verify signatures made with versions older than v", minSupportedVersion)
die("Cannot verify signatures made with versions older than v", minSupportedVersion)
}
}

Expand Down Expand Up @@ -589,7 +593,7 @@ func main() {
sigData.Signature,
)
default:
l.Fatal("Unsupported signature algorithm. This shouldn't happen, which means you found a bug.")
die("Unsupported signature algorithm. This shouldn't happen, which means you found a bug.")
}

check(err, "Failed to verify signature.")
Expand Down Expand Up @@ -628,16 +632,24 @@ func main() {
displayTime, _ := verificationTime.UTC().MarshalText()
l.Println("Signed by:", getCallsign(*cert), "on", string(displayTime))
if textMode {
// Text mode file output tries to preserve anything not bracketed with the "signed text"
// markers, and instead brackets it in new ones which say the signed text was verified.
newLine := detectNewline(string(fileData))
textData := []byte(rawTextHeader)
textData = append(textData, []byte("-----LOTW-TRUST SIGNED----"+newLine)...)
textData = append(textData, fileData...)
textData = append(textData, []byte(fmt.Sprintf(
"%s-----LOTW-TRUST VERIFIED-----%sSigned by: %s on %s", newLine, newLine,
getCallsign(*cert),
string(displayTime)))...)
textData = append(textData, []byte(rawTextFooter)...)
fileData = textData
fileData = bytes.Join(
[][]byte{
[]byte(rawTextHeader),
[]byte("-----LOTW-TRUST SIGNED----" + newLine),
fileData,
[]byte(fmt.Sprintf(
"%s-----LOTW-TRUST VERIFIED-----%sSigned by: %s on %s",
newLine,
newLine,
getCallsign(*cert),
string(displayTime))),
[]byte(rawTextFooter),
},
[]byte{},
)
}

saveFile(outputFile, fileData)
Expand Down

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