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formalize token munging code

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This commit is contained in:
Shivaram Lingamneni 2019-05-15 05:00:55 -04:00
parent 84fe2c60dd
commit 7d53dd5d81
3 changed files with 57 additions and 11 deletions
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16
irc/channel.go
View File

@ -777,12 +777,6 @@ func stripMaskFromNick(nickMask string) (nick string) {
return nickMask[0:index]
}
// munge the msgid corresponding to a replayable event,
// yielding a consistent msgid for the fake PRIVMSG from HistServ
func mungeMsgidForHistserv(token string) (result string) {
return fmt.Sprintf("_%s", token)
}
func (channel *Channel) replayHistoryItems(rb *ResponseBuffer, items []history.Item, autoreplay bool) {
chname := channel.Name()
client := rb.target
@ -823,7 +817,7 @@ func (channel *Channel) replayHistoryItems(rb *ResponseBuffer, items []history.I
} else {
message = fmt.Sprintf(client.t("%[1]s [account: %[2]s] joined the channel"), nick, item.AccountName)
}
rb.AddFromClient(item.Message.Time, mungeMsgidForHistserv(item.Message.Msgid), "HistServ", "*", nil, "PRIVMSG", chname, message)
rb.AddFromClient(item.Message.Time, utils.MungeSecretToken(item.Message.Msgid), "HistServ", "*", nil, "PRIVMSG", chname, message)
}
case history.Part:
if eventPlayback {
@ -833,14 +827,14 @@ func (channel *Channel) replayHistoryItems(rb *ResponseBuffer, items []history.I
continue // #474
}
message := fmt.Sprintf(client.t("%[1]s left the channel (%[2]s)"), nick, item.Message.Message)
rb.AddFromClient(item.Message.Time, mungeMsgidForHistserv(item.Message.Msgid), "HistServ", "*", nil, "PRIVMSG", chname, message)
rb.AddFromClient(item.Message.Time, utils.MungeSecretToken(item.Message.Msgid), "HistServ", "*", nil, "PRIVMSG", chname, message)
}
case history.Kick:
if eventPlayback {
rb.AddFromClient(item.Message.Time, item.Message.Msgid, item.Nick, item.AccountName, nil, "HEVENT", "KICK", chname, item.Params[0], item.Message.Message)
} else {
message := fmt.Sprintf(client.t("%[1]s kicked %[2]s (%[3]s)"), nick, item.Params[0], item.Message.Message)
rb.AddFromClient(item.Message.Time, mungeMsgidForHistserv(item.Message.Msgid), "HistServ", "*", nil, "PRIVMSG", chname, message)
rb.AddFromClient(item.Message.Time, utils.MungeSecretToken(item.Message.Msgid), "HistServ", "*", nil, "PRIVMSG", chname, message)
}
case history.Quit:
if eventPlayback {
@ -850,14 +844,14 @@ func (channel *Channel) replayHistoryItems(rb *ResponseBuffer, items []history.I
continue // #474
}
message := fmt.Sprintf(client.t("%[1]s quit (%[2]s)"), nick, item.Message.Message)
rb.AddFromClient(item.Message.Time, mungeMsgidForHistserv(item.Message.Msgid), "HistServ", "*", nil, "PRIVMSG", chname, message)
rb.AddFromClient(item.Message.Time, utils.MungeSecretToken(item.Message.Msgid), "HistServ", "*", nil, "PRIVMSG", chname, message)
}
case history.Nick:
if eventPlayback {
rb.AddFromClient(item.Message.Time, item.Message.Msgid, item.Nick, item.AccountName, nil, "HEVENT", "NICK", item.Params[0])
} else {
message := fmt.Sprintf(client.t("%[1]s changed nick to %[2]s"), nick, item.Params[0])
rb.AddFromClient(item.Message.Time, mungeMsgidForHistserv(item.Message.Msgid), "HistServ", "*", nil, "PRIVMSG", chname, message)
rb.AddFromClient(item.Message.Time, utils.MungeSecretToken(item.Message.Msgid), "HistServ", "*", nil, "PRIVMSG", chname, message)
}
}
}

23
irc/utils/crypto.go
View File

@ -28,6 +28,29 @@ func GenerateSecretToken() string {
return B32Encoder.EncodeToString(buf[:])
}
// "munge" a secret token to a new value. requirements:
// 1. MUST be roughly as unlikely to collide with `GenerateSecretToken` outputs
// as those outputs are with each other
// 2. SHOULD be deterministic (motivation: if a JOIN line has msgid x,
// create a deterministic msgid y for the fake HistServ PRIVMSG that "replays" it)
// 3. SHOULD be in the same "namespace" as `GenerateSecretToken` outputs
// (same length and character set)
func MungeSecretToken(token string) (result string) {
bytes, err := B32Encoder.DecodeString(token)
if err != nil {
// this should never happen
return GenerateSecretToken()
}
// add 1 with carrying
for i := len(bytes) - 1; 0 <= i; i -= 1 {
bytes[i] += 1
if bytes[i] != 0 {
break
} // else: overflow, carry to the next place
}
return B32Encoder.EncodeToString(bytes)
}
// securely check if a supplied token matches a stored token
func SecretTokensMatch(storedToken string, suppliedToken string) bool {
// XXX fix a potential gotcha: if the stored token is uninitialized,

29
irc/utils/crypto_test.go
View File

@ -47,8 +47,37 @@ func TestTokenCompare(t *testing.T) {
}
}
func TestMunging(t *testing.T) {
count := 131072
set := make(map[string]bool)
var token string
for i := 0; i < count; i++ {
token = GenerateSecretToken()
set[token] = true
}
// all tokens generated thus far should be unique
assertEqual(len(set), count, t)
// iteratively munge the last generated token an additional `count` times
mungedToken := token
for i := 0; i < count; i++ {
mungedToken = MungeSecretToken(mungedToken)
assertEqual(len(mungedToken), len(token), t)
set[mungedToken] = true
}
// munged tokens should not collide with generated tokens, or each other
assertEqual(len(set), count*2, t)
}
func BenchmarkGenerateSecretToken(b *testing.B) {
for i := 0; i < b.N; i++ {
GenerateSecretToken()
}
}
func BenchmarkMungeSecretToken(b *testing.B) {
t := GenerateSecretToken()
for i := 0; i < b.N; i++ {
t = MungeSecretToken(t)
}
}