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update obfuscation
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@rusq
rusq committed Mar 4, 2023
1 parent 595d56b commit 340cd41
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Showing 5 changed files with 76 additions and 39 deletions.
41 changes: 41 additions & 0 deletions internal/chunk/obfuscate/ids.go
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Original file line number Diff line number Diff line change
@@ -0,0 +1,41 @@
package obfuscate

import (
"encoding/hex"
"strings"
)

const (
userPrefix = "UO"
chanPrefix = "CO"
filePrefix = "FO"
teamPrefix = "TO"
)

// ID obfuscates an ID.
func (o obfuscator) ID(prefix string, id string) string {
if id == "" {
return ""
}
h := o.hasher()
if _, err := h.Write([]byte(o.salt + id)); err != nil {
panic(err)
}
return prefix + strings.ToUpper(hex.EncodeToString(h.Sum(nil)))[:len(id)-1]
}

func (o obfuscator) UserID(u string) string {
return o.ID(userPrefix, u)
}

func (o obfuscator) ChannelID(c string) string {
return o.ID(chanPrefix, c)
}

func (o obfuscator) FileID(f string) string {
return o.ID(filePrefix, f)
}

func (o obfuscator) TeamID(g string) string {
return o.ID(teamPrefix, g)
}
48 changes: 20 additions & 28 deletions internal/chunk/obfuscate/obfuscate.go
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Original file line number Diff line number Diff line change
Expand Up @@ -8,7 +8,6 @@ package obfuscate
import (
"context"
"crypto/sha256"
"encoding/hex"
"encoding/json"
"hash"
"io"
Expand Down Expand Up @@ -80,7 +79,7 @@ type obfuscator struct {
}

func (o obfuscator) Chunk(c *chunk.Chunk) {
c.ChannelID = o.ID("C", c.ChannelID)
c.ChannelID = o.ChannelID(c.ChannelID)
switch c.Type {
case chunk.CMessages:
o.Messages(c.Messages...)
Expand All @@ -105,7 +104,7 @@ func (o obfuscator) Messages(m ...slack.Message) {
}
}

const filePrefix = "https://files.slack.com/"
const fileURLPrefix = "https://files.slack.com/"

func notNilFn(s string, fn func(string) string) string {
if s != "" {
Expand All @@ -119,14 +118,14 @@ func (o obfuscator) OneMessage(m *slack.Message) {
return
}
m.ClientMsgID = notNilFn(m.ClientMsgID, func(s string) string { return randomUUID() })
m.Team = o.ID("T", m.Team)
m.Channel = o.ID("C", m.Channel)
m.User = o.ID("U", m.User)
m.Team = o.TeamID(m.Team)
m.Channel = o.UserID(m.Channel)
m.User = o.UserID(m.User)
if m.Text != "" {
m.Text = randomString(len(m.Text))
}
if m.Edited != nil {
m.Edited.User = o.ID("U", m.Edited.User)
m.Edited.User = o.UserID(m.Edited.User)
}
if len(m.Blocks.BlockSet) > 0 {
m.Blocks.BlockSet = nil // too much hassle to obfuscate
Expand All @@ -138,7 +137,7 @@ func (o obfuscator) OneMessage(m *slack.Message) {
m.Attachments = nil // too much hassle to obfuscate
}
if m.ParentUserId != "" {
m.ParentUserId = o.ID("U", m.ParentUserId)
m.ParentUserId = o.UserID(m.ParentUserId)
}
for i := range m.Files {
o.OneFile(&m.Files[i])
Expand All @@ -157,8 +156,8 @@ func (o obfuscator) OneFile(f *slack.File) {
}
ifnotnil := func(s string) string {
if s != "" {
if strings.HasPrefix(s, filePrefix) {
s = filePrefix + randomString(len(s)-len(filePrefix))
if strings.HasPrefix(s, fileURLPrefix) {
s = fileURLPrefix + randomString(len(s)-len(fileURLPrefix))
} else {
s = randomString(len(s))
}
Expand Down Expand Up @@ -198,8 +197,8 @@ func (o obfuscator) OneFile(f *slack.File) {
f.OriginalW = 0
f.OriginalH = 0
f.InitialComment = slack.Comment{}
f.User = o.ID("U", f.User)
f.ID = o.ID("F", f.ID)
f.User = o.UserID(f.User)
f.ID = o.FileID(f.ID)
}

// randomString returns a random string of length n + random number [0,40).
Expand Down Expand Up @@ -241,23 +240,11 @@ func randomUUID() string {
return string(b)
}

// ID obfuscates an ID.
func (o obfuscator) ID(prefix string, id string) string {
if id == "" {
return ""
}
h := o.hasher()
if _, err := h.Write([]byte(o.salt + id)); err != nil {
panic(err)
}
return prefix + strings.ToUpper(hex.EncodeToString(h.Sum(nil)))[:len(id)-1]
}

func (o obfuscator) Reactions(r []slack.ItemReaction) {
for i := range r {
r[i].Name = randomStringExact(len(r[i].Name))
for j := range r[i].Users {
r[i].Users[j] = o.ID("U", r[i].Users[j])
r[i].Users[j] = o.UserID(r[i].Users[j])
}
}
}
Expand All @@ -266,13 +253,18 @@ func (o obfuscator) Channel(c *slack.Channel) {
if c == nil {
return
}
c.ID = o.ID("C", c.ID)
c.Creator = o.ID("U", c.Creator)
c.ID = o.ChannelID(c.ID)
c.Creator = o.UserID(c.Creator)
c.Name = o.ID("", c.Name)
c.NameNormalized = o.ID("", c.NameNormalized)

c.Purpose.Value = randomStringExact(len(c.Purpose.Value))
c.Purpose.Creator = o.UserID(c.Purpose.Creator)

c.Topic.Value = randomStringExact(len(c.Topic.Value))
c.Topic.Creator = o.UserID(c.Topic.Creator)

for i := range c.Members {
c.Members[i] = o.ID("U", c.Members[i])
c.Members[i] = o.UserID(c.Members[i])
}
}
24 changes: 14 additions & 10 deletions internal/chunk/obfuscate/obfuscate_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -141,10 +141,10 @@ func Test_obfuscator_OneMessage(t *testing.T) {
ClientMsgID: "a29ab0f5-808b-bc8e-f22e-b4ac1a00fcd4",
Type: "message",
Channel: "",
User: "U8EEA06E1",
User: userPrefix + "8EEA06E1",
Text: "9 LVwGabEN7FkWNmyD0HtOdvcYYvfHfF hVA6Nd1BtVOw52BH40tQ4xsZr1rbOE",
Timestamp: "1645095505.023899",
Team: "TEBC93378",
Team: teamPrefix + "EBC93378",
},
},
},
Expand Down Expand Up @@ -199,15 +199,15 @@ func Test_obfuscator_OneFile(t *testing.T) {
f: fixtures.Load[*slack.File](fixtures.FileJPEG),
},
wantFile: &slack.File{
ID: "F8B5BAA15C4",
ID: filePrefix + "8B5BAA15C4",
Created: 1638784624,
Timestamp: 1638784624,
Name: "N1CIe93m6sjyQtxxQ",
Title: "NrZ60 cPGC7",
Mimetype: "image/jpeg",
Filetype: "jpg",
PrettyType: "JPEG",
User: "U8EEA06E1",
User: userPrefix + "8EEA06E1",
Mode: "hosted",
Size: 359002,
URLPrivate: "https://files.slack.com/jXUJR9JT5pul5g8MDbK7E1ycTwBhzdJG9 LVwGabEN7FkWNmyD0HtOdvcYYvfHfF hVA6Nd1BtVOw52BH40tQ4xsZr1rbOEdndtLrooKH5L9GzLgWmmWfVTBKfSvym98qEQMYaWdLEKrJCEXzYB2bFiOLzhK",
Expand Down Expand Up @@ -246,10 +246,12 @@ var testChan = &slack.Channel{
IsArchived: false,
Creator: "U024BE7LH",
Topic: slack.Topic{
Value: "Fun times",
Value: "Fun times",
Creator: "U024BE7LV",
},
Purpose: slack.Purpose{
Value: "A place for non-work-related flimflam.",
Value: "A place for non-work-related flimflam.",
Creator: "U024BE7LH",
},
Conversation: slack.Conversation{
ID: "C0G9QF9GW",
Expand Down Expand Up @@ -287,15 +289,17 @@ func Test_obfuscator_Channel(t *testing.T) {
GroupConversation: slack.GroupConversation{
Name: "55D55",
IsArchived: false,
Creator: "UF209DFAC",
Creator: userPrefix + "F209DFAC",
Topic: slack.Topic{
Value: "GabEN7FkW",
Value: "GabEN7FkW",
Creator: userPrefix + "0077C5B4",
},
Purpose: slack.Purpose{
Value: "2jXUJR9JT5pul5g8MDbK7E1ycTwBhzdJG9 LVw",
Value: "2jXUJR9JT5pul5g8MDbK7E1ycTwBhzdJG9 LVw",
Creator: userPrefix + "F209DFAC",
},
Conversation: slack.Conversation{
ID: "C0250C11A",
ID: chanPrefix + "0250C11A",
IsGroup: false,
Created: 1449252882,
},
Expand Down
Binary file modified internal/fixtures/assets/chunks.jsonl.gz
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2 changes: 1 addition & 1 deletion internal/fixtures/chunk.go
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Original file line number Diff line number Diff line change
Expand Up @@ -14,7 +14,7 @@ import (
//go:embed assets/chunks.jsonl.gz
var chunksJsonlGz []byte

const ChunkFileChannelID = "C73D19AAE17"
const ChunkFileChannelID = "CO73D19AAE17"

// chunksJSONL returns a reader for the b []byte, which assumed to be a
// gzip-compressed bytes slice. It panics on error.
Expand Down

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