Add TNEF handling and email loading improvements
- Implement TNEF extraction and recursive parsing in new `tnef_reader.go` and associated tests. - Create tests for TNEF extraction scenarios in `tnef_diag_test.go`, `tnef_diag7_test.go`, and `tnef_diag8_test.go`.
This commit is contained in:
Flavio Fois
273
backend/utils/mail/tnef_diag7_test.go
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273
backend/utils/mail/tnef_diag7_test.go
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package internal
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import (
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"bytes"
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"encoding/binary"
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"fmt"
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"io"
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"os"
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"strings"
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"testing"
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"github.com/teamwork/tnef"
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)
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func TestTNEFRecursiveExtract(t *testing.T) {
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testFile := `H:\Dev\Gits\EMLy\EML_TNEF.eml`
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if _, err := os.Stat(testFile); os.IsNotExist(err) {
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t.Skip("test EML file not present")
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}
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f, _ := os.Open(testFile)
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defer f.Close()
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outerEmail, _ := Parse(f)
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var innerData []byte
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for _, att := range outerEmail.Attachments {
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if strings.Contains(strings.ToLower(att.Filename), "postacert.eml") {
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innerData, _ = io.ReadAll(att.Data)
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break
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}
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}
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innerEmail, _ := Parse(bytes.NewReader(innerData))
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for _, att := range innerEmail.Attachments {
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rawData, _ := io.ReadAll(att.Data)
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if strings.ToLower(att.Filename) != "winmail.dat" {
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continue
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}
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fmt.Println("=== Level 0 (top TNEF) ===")
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atts, body := recursiveExtract(rawData, 0)
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fmt.Printf("\nTotal extracted attachments: %d\n", len(atts))
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for i, a := range atts {
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fmt.Printf(" [%d] %q (%d bytes)\n", i, a.Title, len(a.Data))
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}
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fmt.Printf("Body HTML len: %d\n", len(body))
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if len(body) > 0 && len(body) < 500 {
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fmt.Printf("Body: %s\n", body)
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}
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}
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}
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func recursiveExtract(tnefData []byte, depth int) ([]*tnef.Attachment, string) {
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prefix := strings.Repeat(" ", depth)
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decoded, err := tnef.Decode(tnefData)
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if err != nil {
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fmt.Printf("%sDecode error: %v\n", prefix, err)
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return nil, ""
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}
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// Collect body
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bodyHTML := string(decoded.BodyHTML)
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bodyText := string(decoded.Body)
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// Check for RTF body in attributes
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for _, attr := range decoded.Attributes {
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if attr.Name == 0x1009 {
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fmt.Printf("%sFound PR_RTF_COMPRESSED: %d bytes\n", prefix, len(attr.Data))
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}
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if attr.Name == 0x1000 {
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fmt.Printf("%sFound PR_BODY: %d bytes\n", prefix, len(attr.Data))
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if bodyText == "" {
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bodyText = string(attr.Data)
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}
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}
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if attr.Name == 0x1013 || attr.Name == 0x1035 {
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fmt.Printf("%sFound PR_BODY_HTML/PR_HTML: %d bytes\n", prefix, len(attr.Data))
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if bodyHTML == "" {
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bodyHTML = string(attr.Data)
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}
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}
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}
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fmt.Printf("%sAttachments: %d, Body: %d, BodyHTML: %d\n",
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prefix, len(decoded.Attachments), len(bodyText), len(bodyHTML))
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var allAttachments []*tnef.Attachment
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// Collect real attachments (skip placeholders)
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for _, a := range decoded.Attachments {
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if a.Title == "Untitled Attachment" && len(a.Data) < 200 {
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fmt.Printf("%sSkipping placeholder: %q (%d bytes)\n", prefix, a.Title, len(a.Data))
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continue
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}
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allAttachments = append(allAttachments, a)
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}
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// Now scan for embedded messages in raw TNEF
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embeddedStreams := findEmbeddedTNEFStreams(tnefData)
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for i, stream := range embeddedStreams {
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fmt.Printf("%s--- Recursing into embedded message %d (%d bytes) ---\n", prefix, i, len(stream))
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subAtts, subBody := recursiveExtract(stream, depth+1)
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allAttachments = append(allAttachments, subAtts...)
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if bodyHTML == "" && subBody != "" {
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bodyHTML = subBody
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}
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}
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if bodyHTML != "" {
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return allAttachments, bodyHTML
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}
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return allAttachments, bodyText
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}
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func findEmbeddedTNEFStreams(tnefData []byte) [][]byte {
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var streams [][]byte
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// Navigate through TNEF attributes
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offset := 6
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for offset+9 < len(tnefData) {
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level := tnefData[offset]
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attrID := binary.LittleEndian.Uint32(tnefData[offset+1 : offset+5])
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attrLen := int(binary.LittleEndian.Uint32(tnefData[offset+5 : offset+9]))
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dataStart := offset + 9
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if dataStart+attrLen > len(tnefData) {
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break
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}
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// attAttachment (0x9005) at attachment level
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if level == 0x02 && attrID == 0x00069005 && attrLen > 100 {
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mapiData := tnefData[dataStart : dataStart+attrLen]
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embedded := extractPRAttachDataObj2(mapiData)
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if embedded != nil && len(embedded) > 22 {
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// Skip 16-byte GUID, check for TNEF signature
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afterGuid := embedded[16:]
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if len(afterGuid) >= 4 {
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sig := binary.LittleEndian.Uint32(afterGuid[0:4])
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if sig == 0x223E9F78 {
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streams = append(streams, afterGuid)
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}
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}
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}
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}
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offset += 9 + attrLen + 2
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}
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return streams
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}
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func extractPRAttachDataObj2(mapiData []byte) []byte {
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if len(mapiData) < 4 {
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return nil
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}
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count := int(binary.LittleEndian.Uint32(mapiData[0:4]))
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offset := 4
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for i := 0; i < count && offset+4 <= len(mapiData); i++ {
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propTag := binary.LittleEndian.Uint32(mapiData[offset : offset+4])
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propType := propTag & 0xFFFF
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propID := (propTag >> 16) & 0xFFFF
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offset += 4
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if propID >= 0x8000 {
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if offset+20 > len(mapiData) {
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return nil
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}
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kind := binary.LittleEndian.Uint32(mapiData[offset+16 : offset+20])
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offset += 20
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if kind == 0 {
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offset += 4
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} else {
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if offset+4 > len(mapiData) {
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return nil
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}
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nameLen := int(binary.LittleEndian.Uint32(mapiData[offset : offset+4]))
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offset += 4 + nameLen
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if nameLen%4 != 0 {
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offset += 4 - nameLen%4
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}
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}
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}
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switch propType {
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case 0x0002:
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offset += 4
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case 0x0003:
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offset += 4
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case 0x000B:
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offset += 4
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case 0x0040:
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offset += 8
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case 0x001E, 0x001F:
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if offset+4 > len(mapiData) {
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return nil
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}
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cnt := int(binary.LittleEndian.Uint32(mapiData[offset : offset+4]))
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offset += 4
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for j := 0; j < cnt; j++ {
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if offset+4 > len(mapiData) {
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return nil
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}
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slen := int(binary.LittleEndian.Uint32(mapiData[offset : offset+4]))
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offset += 4 + slen
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if slen%4 != 0 {
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offset += 4 - slen%4
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}
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}
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case 0x0102:
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if offset+4 > len(mapiData) {
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return nil
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}
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cnt := int(binary.LittleEndian.Uint32(mapiData[offset : offset+4]))
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offset += 4
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for j := 0; j < cnt; j++ {
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if offset+4 > len(mapiData) {
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return nil
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}
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blen := int(binary.LittleEndian.Uint32(mapiData[offset : offset+4]))
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offset += 4 + blen
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if blen%4 != 0 {
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offset += 4 - blen%4
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}
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}
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case 0x000D:
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if offset+4 > len(mapiData) {
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return nil
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}
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cnt := int(binary.LittleEndian.Uint32(mapiData[offset : offset+4]))
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offset += 4
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for j := 0; j < cnt; j++ {
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if offset+4 > len(mapiData) {
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return nil
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}
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olen := int(binary.LittleEndian.Uint32(mapiData[offset : offset+4]))
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offset += 4
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if propID == 0x3701 {
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return mapiData[offset : offset+olen]
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}
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offset += olen
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if olen%4 != 0 {
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offset += 4 - olen%4
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}
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}
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case 0x1003:
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if offset+4 > len(mapiData) {
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return nil
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}
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cnt := int(binary.LittleEndian.Uint32(mapiData[offset : offset+4]))
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offset += 4 + cnt*4
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case 0x1102:
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if offset+4 > len(mapiData) {
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return nil
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}
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cnt := int(binary.LittleEndian.Uint32(mapiData[offset : offset+4]))
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offset += 4
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for j := 0; j < cnt; j++ {
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if offset+4 > len(mapiData) {
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return nil
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}
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blen := int(binary.LittleEndian.Uint32(mapiData[offset : offset+4]))
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offset += 4 + blen
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if blen%4 != 0 {
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offset += 4 - blen%4
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}
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}
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default:
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return nil
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}
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}
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return nil
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}
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