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Issue metadata

Status: Fixed
Owner:
Closed: Sep 2017
Cc:
Components:
EstimatedDays: ----
NextAction: ----
OS: Linux , Android , Windows , Chrome , Mac
Pri: 1
Type: Bug-Security



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Security: UAF in CFFL_InteractiveFormFiller::OnBeforeKeyStroke

Reported by manhluat...@gmail.com, Sep 14 2017

Issue description

Notice: this PoC works on stable chrome (XFA disabled)

To repro, open pdf file on Chromium ASAN then click anywhere on page 0.

It even crash on Stable Chrome (MacOS) since I'm using gc();



https://cs.chromium.org/chromium/src/third_party/pdfium/fpdfsdk/formfiller/cffl_interactiveformfiller.cpp?q=CFFL_InteractiveFormFiller::OnBeforeKeyStroke&sq=package:chromium&l=909

std::pair<bool, bool> CFFL_InteractiveFormFiller::OnBeforeKeyStroke(

[...]

  CPDFSDK_Annot::ObservedPtr pObserved(pData->pWidget);
  if (!pData->pWidget->OnAAction(CPDF_AAction::KeyStroke, fa,
                                 pData->pPageView)) { <---- run JS script here
    if (!IsValidAnnot(pData->pPageView, pData->pWidget))
      bExit = true;
    return {bRC, bExit};
  }

  if (!pObserved || !IsValidAnnot(pData->pPageView, pData->pWidget))
    return {bRC, true};

  if (nAge != pData->pWidget->GetAppearanceAge()) {
    CPWL_Wnd* pWnd = pFormFiller->ResetPDFWindow(
        pData->pPageView, nValueAge == pData->pWidget->GetValueAge());
    pData = reinterpret_cast<CFFL_PrivateData*>(pWnd->GetAttachedData());
    bExit = true;
  }

[...]



Root cause:

We can run JS script at 909th line, we can destroy this widget's pdf window,
later it uses |pData| (which is element in PDFWindow class |CPWL_Listbox|)

UAF occurs.

To destroy pdf window:

I killfocus on this annot, then setfocus again (with m_Age has been changed), it will invoke |ResetPDFWindow| afterwards.



                                                    

 
asan
10.6 KB View Download
onbeforekeystroke.pdf
2.5 KB Download
poc.mov
16.4 MB Download
Do we have some way to record properly a chrome window ?

Cause I see some PoC attaching .mp4 video with high quality.

Thanks.


Comment 2 by mea...@chromium.org, Sep 14 2017

Components: Internals>Plugins>PDF
Labels: Security_Severity-High Security_Impact-Stable
Owner: tsepez@chromium.org
Status: Assigned (was: Unconfirmed)
Thanks for the report, I can reproduce the crash. Chrome doesn't have a builtin way of recording windows, but your PoC video is very clear. 

Tom: Can you please take a look? Thanks.
 

Comment 3 by mea...@chromium.org, Sep 14 2017

Labels: OS-Android OS-Chrome OS-Linux OS-Mac OS-Windows Pri-1

Comment 4 by tsepez@chromium.org, Sep 14 2017

Status: Started (was: Assigned)
Project Member

Comment 5 by sheriffbot@chromium.org, Sep 15 2017

Labels: M-61

Comment 6 by tsepez@chromium.org, Sep 15 2017

Cc: rharrison@chromium.org

Comment 7 by tsepez@chromium.org, Sep 15 2017

Status: Fixed (was: Started)
https://pdfium-review.googlesource.com/c/pdfium/+/14050
Project Member

Comment 8 by sheriffbot@chromium.org, Sep 16 2017

Labels: -Restrict-View-SecurityTeam Restrict-View-SecurityNotify
Project Member

Comment 9 by sheriffbot@chromium.org, Sep 18 2017

Labels: Merge-Request-62
Project Member

Comment 10 by sheriffbot@chromium.org, Sep 18 2017

Labels: -Merge-Request-62 Merge-Review-62 Hotlist-Merge-Review
This bug requires manual review: M62 has already been promoted to the beta branch, so this requires manual review
Please contact the milestone owner if you have questions.
Owners: amineer@(Android), cmasso@(iOS), bhthompson@(ChromeOS), abdulsyed@(Desktop)

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot
Cc: awhaley@chromium.org
Labels: -Merge-Review-62 Merge-Approved-62
+awhalley@

I'm approving merge to M62. Branch:3202
Labels: reward-topanel
Labels: -reward-topanel reward-unpaid reward-3000
*** Boilerplate reminders! ***
Please do NOT publicly disclose details until a fix has been released to all our users. Early public disclosure may cancel the provisional reward. Also, please be considerate about disclosure when the bug affects a core library that may be used by other products. Please do NOT share this information with third parties who are not directly involved in fixing the bug. Doing so may cancel the provisional reward. Please be honest if you have already disclosed anything publicly or to third parties. Lastly, we understand that some of you are not interested in money. We offer the option to donate your reward to an eligible charity. If you prefer this option, let us know and we will also match your donation - subject to our discretion. Any rewards that are unclaimed after 12 months will be donated to a charity of our choosing.
*********************************
Nice one! The VRP panel decided to award $3,000 for this report!
Labels: -reward-unpaid reward-inprocess
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Comment 16 by sheriffbot@chromium.org, Sep 22 2017

Cc: abdulsyed@google.com
This issue has been approved for a merge. Please merge the fix to any appropriate branches as soon as possible!

If all merges have been completed, please remove any remaining Merge-Approved labels from this issue.

Thanks for your time! To disable nags, add the Disable-Nags label.

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot
Project Member

Comment 17 by sheriffbot@chromium.org, Sep 25 2017

This issue has been approved for a merge. Please merge the fix to any appropriate branches as soon as possible!

If all merges have been completed, please remove any remaining Merge-Approved labels from this issue.

Thanks for your time! To disable nags, add the Disable-Nags label.

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot
Reminder to please merge to M62 branch 3202.
Will merge.
Labels: -Merge-Approved-62 merge-merged-3202
https://pdfium.googlesource.com/pdfium/+/effa1b15ae2ab34ae15892787d5c1caa015bd2d4
Labels: -M-61 M-62
Labels: Release-0-M62
Labels: CVE-2017-5127
Project Member

Comment 24 by sheriffbot@chromium.org, Dec 23 2017

Labels: -Restrict-View-SecurityNotify allpublic
This bug has been closed for more than 14 weeks. Removing security view restrictions.

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot
Project Member

Comment 25 by bugdroid1@chromium.org, Jan 4 2018

The following revision refers to this bug:
  https://pdfium.googlesource.com/pdfium/+/df0a749452d933e4f434e2a33112667f1880db34

commit df0a749452d933e4f434e2a33112667f1880db34
Author: Dan Sinclair <dsinclair@chromium.org>
Date: Thu Jan 04 20:19:21 2018

Remove allocations from JS test

This CL removes the millions of allocations from the test case for bug
765384. This takes the test execution from ~20s to ~400ms when run in
Debug.

Bug:  chromium:765384 
Change-Id: Ib1e9d3c6fb9853e541189e1a16f765d05202cdcc
Reviewed-on: https://pdfium-review.googlesource.com/22011
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Commit-Queue: dsinclair <dsinclair@chromium.org>

[modify] https://crrev.com/df0a749452d933e4f434e2a33112667f1880db34/testing/resources/bug_765384.in
[modify] https://crrev.com/df0a749452d933e4f434e2a33112667f1880db34/testing/resources/bug_765384.pdf

Project Member

Comment 26 by sheriffbot@chromium.org, Mar 27

Labels: -M-62 M-65
Labels: CVE_description-submitted

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