MS15-124 breaks VBScript's "InstrB" function when working with a byte safearray

Issue #5865907


Dec 14, 2015
This issue is public.
Reported by 0 people

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Steps to reproduce


Repro Steps:

    ' Test.vbs
Dim byteArray, byteArray2, byteArray3, bPosition
Dim responseText

' byte string
' "Hello hello"
byteArray = chrb(104) & chrb(101) & chrb(108) & chrb(108) & chrb(111) & chrb(32) & chrb(104) & chrb(101) & chrb(108) & chrb(108) & chrb(111) & chrb(0)

' byte array - What Response.BinaryRead is
byteArray2 = TextToBytes(byteArray)

' Vartype:
ResponseText = ResponseText + "blen: " & lenb(byteArray) & vbCRLF
ResponseText = ResponseText + "type: " & vartype(byteArray) & vbCRLF

ResponseText = ResponseText + "blen: " & lenb(byteArray2) & vbCRLF
ResponseText = ResponseText + "type: " & vartype(byteArray2) & vbCRLF

bPosition = instrb(1, byteArray, chrb(111))
ResponseText = ResponseText + "Position in string: " & bPosition & vbCRLF

bPosition = instrb(1, byteArray2, chrb(111))
ResponseText = ResponseText + "Position in byte array: " & bPosition & vbCRLF

bPosition = instrb(1, byteArray2, chrb(111) & chrb(32))
ResponseText = ResponseText + "Position in byte array: " & bPosition & vbCRLF

WScript.Echo ResponseText

' Converts a string (8) to a vbArray of bytes (8192 + 17)
Private Function TextToBytes(ByRef pbinBinaryData)
    Dim lobjRs
    Dim llngLength
    Dim lbinBuffer
    CONST adLongVarBinary = 205
    llngLength = LenB(pbinBinaryData)
    Set lobjRs = CreateObject("ADODB.Recordset")
    Call lobjRs.Fields.Append("BinaryData", adLongVarBinary, llngLength)
    Call lobjRs.Open()
    Call lobjRs.AddNew()
    Call lobjRs.Fields("BinaryData").AppendChunk(pbinBinaryData)
    Call lobjRs.Update()
    lbinBuffer = lobjRs.Fields("BinaryData").GetChunk(llngLength)
    Call lobjRs.Close()
    Set lobjRs = Nothing
    TextToBytes = lbinBuffer
End Function

Expected Results:

The InstrB function correctly works on byte arrays when searching for a single byte.

Actual Results:

Dev Channel specific:



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    Comments and activity

    • Microsoft Edge Team

      Changed Assigned To to “Kamen M.”

      Changed Assigned To to “Saty B.”

      Changed Assigned To from “Saty B.” to “Paul C.”

      Changed Status to “Confirmed”

      Changed Assigned To from “Paul C.” to “Hitesh K.”

      Changed Assigned To from “Hitesh K.” to “IE S.”

      Changed Status from “Confirmed”

    • Hello,

      Thank you for providing this information about the issue. We have confirmed the problem, and we are working on a solution for a future build of Edge. We are presently tracking this issue as a duplicate of an existing internal bug report. We look forward to additional feedback you may have on how we can improve Microsoft Edge.

      Best Wishes,
      The MS Edge Team

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