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Issue 778658 link

Starred by 2 users

Issue metadata

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

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Security: content security policy bypass

Reported by, Oct 26 2017

Issue description

chrome 62.0.3202.62 stable

online demo:
firefox & safari block the request,but chrome does not

in one word
"CSP not inherited after iframe navigate to about:blank scheme uri"
68.4 KB View Download
228 KB View Download

Comment 1 by, Oct 26 2017

a simple analyze & patch:
as andy write in
"Inherit CSP when we inherit the security origin"
if the navigation happends in top frame, then the new page does not inherit the security origin
but when the navigation happends in iframe, then the element would inherit the security origin ,but forget to inhreit the CSP

as a matter of fact,this bug occurs because of when iframe location set to about:blank,when it navigate to about:blank again, it would not inhreit the CSP.

consider  issue 669086  and  issue 747847  so far

Comment 2 by, Oct 26 2017

the key point is in

      policy_to_inherit =
      if (url_.IsEmpty() || url_.ProtocolIsAbout() || url_.ProtocolIsData() ||
          url_.ProtocolIs("blob") || url_.ProtocolIs("filesystem")) {

after the check , CSP is not inhreit
inherit_from->GetSecurityContext()->GetContentSecurityPolicy(); may get a null result

Comment 3 by, Oct 26 2017

another possible reason is :
your code did not consider the following situation

when the top frame navigate from to about:blank ,CSP did not need to inhreit because of the page did not inhreit origin.
but in iframe, it inhreit the origin ( so that it need to consider CSP.
so you need to add check in plz navigate
Components: Blink>SecurityFeature>ContentSecurityPolicy

Comment 5 by, Oct 30 2017

Re #5: This issue will be triaged as a part of the normal Chrome security triage process. At first glance, it does not seem to be of particularly high severity.
Labels: Security_Severity-Medium Security_Impact-Stable OS-Android OS-Chrome OS-Linux OS-Mac OS-Windows
Status: Assigned (was: Unconfirmed)
andypaicu: Would you mind taking a look?
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Comment 8 by, Oct 31 2017

Labels: M-63
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Comment 9 by, Oct 31 2017

Labels: Pri-1
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Comment 10 by, Nov 9 2017

andypaicu: Uh oh! This issue still open and hasn't been updated in the last 14 days. This is a serious vulnerability, and we want to ensure that there's progress. Could you please leave an update with the current status and any potential blockers?

If you're not the right owner for this issue, could you please remove yourself as soon as possible or help us find the right one?

If the issue is fixed or you can't reproduce it, please close the bug. If you've started working on a fix, please set the status to Started.

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

For more details visit - Your friendly Sheriffbot
Labels: Hotlist-EnamelAndFriendsFixIt
Status: Started (was: Assigned)
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Comment 13 by, Nov 21 2017

The following revision refers to this bug:

commit 209f225b2d51334eaf69ffdf002e25eaa1e0d448
Author: Andy Paicu <>
Date: Tue Nov 21 14:59:32 2017

Fixed bug where PlzNavigate CSP in a iframe did not get the inherited CSP

When inheriting the CSP from a parent document to a local-scheme CSP,
it does not always get propagated to the PlzNavigate CSP. This means
that PlzNavigate CSP checks (like `frame-src`) would be ran against
a blank policy instead of the proper inherited policy.

Bug:  778658 
Change-Id: I61bb0d432e1cea52f199e855624cb7b3078f56a9
Commit-Queue: Andy Paicu <>
Reviewed-by: Mike West <>
Cr-Commit-Position: refs/heads/master@{#518245}

Status: Fixed (was: Started)
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Comment 15 by, Dec 1 2017

Labels: -Restrict-View-SecurityTeam Restrict-View-SecurityNotify
Labels: reward-topanel
Labels: -M-63 M-64
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Comment 18 by, Dec 15 2017

Labels: Merge-Request-64
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Comment 19 by, Dec 15 2017

Labels: -Merge-Request-64 Hotlist-Merge-Review Merge-Review-64
This bug requires manual review: M64 has already been promoted to the beta branch, so this requires manual review
Please contact the milestone owner if you have questions.
Owners: cmasso@(Android), cmasso@(iOS), kbleicher@(ChromeOS), abdulsyed@(Desktop)

For more details visit - Your friendly Sheriffbot
Labels: -Hotlist-Merge-Review -Merge-Review-64
Fix is already in 64.
Labels: -reward-topanel reward-unpaid reward-1000
*** Boilerplate reminders! ***
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Thanks! $1,000 for this report from the VRP panel.
Labels: -reward-unpaid reward-inprocess
Labels: Release-0-M64
Labels: CVE-2018-6040
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Comment 26 by, Mar 8 2018

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

For more details visit - Your friendly Sheriffbot
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Comment 27 by, Mar 27 2018

Labels: -M-64 M-65
Labels: CVE_description-missing
Labels: -CVE_description-missing CVE_description-submitted

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