162409 - Can trick layout history into filling <input type=file> with text from <input type=text> using key collision

Status: VERIFIED FIXED

(Core :: Security, defect)

Description

[Jesse Ruderman]

Layout history uses keys that look like this to refill forms in session history:
Tagname>InputName>InputType>FormName>IndexInForm

InputName and FormName can contain the > character, so it is possible to trick
layout history into filling the contents of a text field into a file-upload
field.  This allows an attacker to upload a file if he knows its filename.

Comment 1

[Jesse Ruderman]

Attachment: lame demo

I'm working on a better demo.

Comment 2

[Jesse Ruderman]

Attachment: better demo: uploads c:\test.txt

Thanks to jesus_X and grok for writing the server side of this demo.

Comment 3

[John Keiser (jkeiser)]

Attachment: Patch

This fixes the problem by putting all developer-controlled elements *after*
non-developer-controlled elements like type in the key.  Because the key is
used only to match, if the first part (containing the type) does not match the
entire key cannot match.  And since none of the things inserted can be
controlled directly by the developer, there is no chance of messing up that
crucial part. 

This has been tested against http://www.johnkeiser.com/cgi-bin/mozform.pl (to
ensure no regressions), Bugzilla bug entry and attachment pages, and the
enclosed testcase.

Comment 4

[John Keiser (jkeiser)]

Attachment: Patch -u

Universal diff of previous patch.

Comment 5

[John Keiser (jkeiser)]

sicking, bz, reviews?

Comment 6

[Boris Zbarsky [:bzbarsky]]

Comment on attachment 95074 [details] [diff] [review]
Patch -u

sr=bzbarsky

Comment 7

[Jonas Sicking (:sicking) No longer reading bugmail consistently]

Comment on attachment 95074 [details] [diff] [review]
Patch -u

r=sicking

Comment 8

[Jonas Sicking (:sicking) No longer reading bugmail consistently]

It might be worth adding some comment to make sure that noone changes this
again. IE something about that author-data should be last so that it can't
tamper with the type.

Comment 9

[John Keiser (jkeiser)]

I actually considered that but figured people watching the checkin would notice;
it would be nice to make this checkin seem as benign as humanly possible given
the horrifying scope of the exploit.

Comment 10

[Jaime Rodriguez, Jr.]

Marking as ADT2 RTM, until we can discuss the severity and discoverability of
this one with jesse and mitch.

Comment 11

[John Keiser (jkeiser)]

Fix checked in to trunk.  Leaving open until we decide what else to do with it.

Comment 12

[John Keiser (jkeiser)]

Comment on attachment 95074 [details] [diff] [review]
Patch -u

a=asa for 1.0.x (asa gave approval just now)

Comment 13

[John Keiser (jkeiser)]

Checked in on 1.1 branch.

Comment 14

[John Keiser (jkeiser)]

Attachment: Linux-friendly testcase

Comment 15

[Christine Hoffman]

Tested on Linux with the following:

1. Netscape 7.0 PR1
2. Patch build based on 8/13 trunk build

Using the testcase created in comment 14, clicked on the button 'Make me upload
/etc/passwd'.

Results:
In Netscape 7.0PR1 contents of file were returned.
With patch build, contents of file were NOT returned.

Comment 16

[scottputterman]

adding adt1.0.1+.  Please check this in tonight.

Comment 17

[Jaime Rodriguez, Jr.]

jkeiser: Did we not check this into the 1.0 branch? Ia sk because there is no
"fixed1.0.1" marking in the keywords, nor did I see a comment saying this was
checked into the 1.0 branch, after Scott provided ADT approval. Pls advise ...

Comment 18

[scottputterman]

According to bonsai, this was checked in last night, so marking fixed1.0.1

Comment 19

[John Keiser (jkeiser)]

Yes, sorry, things got hectic last night.  It should be in this morning's builds.

This is all the builds I am concerned with, resolving fixed.

We need to notify the embedders we know about so that they can pick up this fix.

Comment 20

[Jaime Rodriguez, Jr.]

bsharma: bindu, pls verify this as fixed on the 1.0 branch and the trunk.

Comment 21

[bsharma]

Verified on 2002-08-14-trunk build on Win 2000.

Loaded test cases in comment #1, #2, #3.

All of them give either error or exception in the JS console.

Comment 22

[bsharma]

Verified on 2002-08-15-branch build on Win 2000.

Loaded comment #1, #2 and #3 and all of them gave the appropriate error messages.