CVE-2015-1262

CVE: CVE-2015-1262
CWE:
- 456
- 17
bugs:
- 476647
repo: 
vccs:
- note: Made a revert here that could fix this problem in some cases. See 'interesting_commits'
    section for more info.
  commit: fa6c3f7bc3cabfdae1fa852713f3554e9d6b25c6
fixes:
- note: ''
  commit: d8fccaec4e73a9120074293c1997f963f810c9dd
bounty:
  date: '2015-05-19 11:49:00.000000000 -04:00'
  amount: 500.0
  references:
  - http://chromereleases.googleblog.com/2015/05/stable-channel-update_19.html
lessons:
  yagni:
    note: 
    applies: 
  question: |
    Are there any common lessons we have learned from class that apply to this
    vulnerability? In other words, could this vulnerability serve as an example
    of one of those lessons?

    Leave "applies" blank or put false if you did not see that lesson (you do
    not need to put a reason). Put "true" if you feel the lesson applies and put
    a quick explanation of how it applies.

    Don't feel the need to claim that ALL of these apply, but it's pretty likely
    that one or two of them apply.

    If you think of another lesson we covered in class that applies here, feel
    free to give it a small name and add one in the same format as these.
  serial_killer:
    note: 
    applies: 
  complex_inputs:
    note: 
    applies: 
  distrust_input:
    note: Functions and classes should distrust input from other functions and/or
      classes. The functions that have to work with the width field after it was supposed
      to be set by the HarfBuzzShaper::shape() functions, should not trust that the
      value is correct and should check if the field is set to a proper value, and
      if not then it should be set by that other function.
    applies: true
  least_privilege:
    note: 
    applies: 
  native_wrappers:
    note: 
    applies: 
  defense_in_depth:
    note: 
    applies: 
  secure_by_default:
    note: 
    applies: 
  environment_variables:
    note: 
    applies: 
  security_by_obscurity:
    note: 
    applies: 
  frameworks_are_optional:
    note: 
    applies: 
reviews:
- 1108663003
- 1137843003
- 1103233003
upvotes: 8
mistakes:
  answer: The mistake was mostly a design issue. They initialized the variable, but
    it was initialized after a condition was checked. If the condition passed it would
    return and the value was never set, so the value just needed to be set at an earlier
    point in the code, which is what they did to mitiigate. To prevent against this
    issue , or mistakes similar to this, they could have code reviews to catch design/coding
    flaws that have the potential to harm the system such as this one. Another way
    to prevent against something like this would be to use TDD (test driven development).
    This way, when going through the conditions in the HarfBuzzShaper::shape() function,
    they could check for what the values of certain fields are, or if those fields
    were even set at all, and correct the issue if anything was not what it should
    be.
  question: |
    In your opinion, after all of this research, what mistakes were made that
    led to this vulnerability? Coding mistakes? Design mistakes?
    Maintainability? Requirements? Miscommunications?

    Look at the CWE entry for this vulnerability and examine the mitigations
    they have written there. Are they doing those? Does the fix look proper?

    Use those questions to inspire your answer. Don't feel obligated to answer
    every one. Write a thoughtful entry here that those ing the software
    engineering industry would find interesting.
announced: '2015-05-20 06:59:14.370000000 -04:00'
subsystem:
  name: Shaping
  answer: Based on the Parent Folder name, blog and module name
  question: |
    What subsystems was the mistake in?

    Look at the path of the source code files code that were fixed to get
    directory names. Look at comments in the code. Look at the bug reports how
    the bug report was tagged. Examples: "clipboard", "gpu", "ssl", "speech", "renderer"
discovered:
  date: '2015-04-13'
  answer: This vulnerability was discovered by ClusterFuzz - An uninitialized value
    was being returned by a function which was causing an error when a tool(Skia)
    was was trying to use that value to draw the bounding box for a TextBlob.
  google: true
  contest: 
  question: |
    How was this vulnerability discovered?

    Go to the bug report and read the conversation to find out how this was
    originally found. Answer in longform below in "answer", fill in the date in
    YYYY-MM-DD, and then determine if the vulnerability was found by a Google
    employee (you can tell from their email address). If it's clear that the
    vulenrability was discovered by a contest, fill in the name there.

    The "automated" flag can be true, false, or nil.
    The "google" flag can be true, false, or nil.

    If there is no evidence as to how this vulnerability was found, then you may
    leave the entries blank except for "answer". Write down where you looked in "answer".
  automated: true
description: A width field, m_totalWidth, was not initialized, but was used in other
  areas of the code. This could have caused denial of service or other unspecified
  impact via Unicode text.
unit_tested:
  fix: true
  code: true
  answer: Tests did not exist before the fix, but they were added with the fix. Tests
    did exist for the entire module beforehand.
  question: |
    Were automated unit tests involved in this vulnerability?
    Was the original code unit tested, or not unit tested? Did the fix involve
    improving the automated tests?

    For the "code" answer below, look not only at the fix but the surrounding
    code near the fix and determine if and was there were unit tests involved
    for this module.

    For the "fix" answer below, check if the fix for the vulnerability involves
    adding or improving an automated test to ensure this doesn't happen again.
major_events:
  answer: I did not notice any major events.
  events:
  - date: 
    name: 
  - date: 
    name: 
  question: |
    Please record any major events you found in the history of this
    vulnerability. Was the code rewritten at some point? Was a nearby subsystem
    changed? Did the team change?

    The event doesn't need to be directly related to this vulnerability, rather,
    we want to capture what the development team was dealing with at the time.
curation_level: 0
CWE_instructions: |
  Please go to cwe.mitre.org and find the most specific, appropriate CWE entry
  that describes your vulnerability. (Tip: this may not be a good one to start
  with - spend time understanding this vulnerability before making your choice!)
bounty_instructions: |
  If you came across any indications that a bounty was paid out for this
  vulnerability, fill it out here. Or correct it if the information already here
  was wrong. Otherwise, leave it blank.
interesting_commits:
  answer: 
  commits:
  - note: They reverted back to broken code because it interferred with how other
      parts of the module was working, where in the m_totalWidth variable was set
      after the conditional was set. They had to rework a more robust fix. Since there
      was a condition that returned a boolean above where the value was set, the reverted
      code only fixed the vulnerability when the condition didn't pass.
    commit: fa6c3f7bc3cabfdae1fa852713f3554e9d6b25c6
  - note: 
    commit: 
  question: |
    Are there any interesting commits between your VCC(s) and fix(es)?

    Write a brief (under 100 words) description of why you think this commit was
    interesting in light of the lessons learned from this vulnerability. Any
    emerging themes?

    If there are no interesting commits, demonstrate that you completed this section by explaining what happened between the VCCs and the fix.
curated_instructions: |
  If you are manually editing this file, then you are "curating" it. Set the
  entry below to "true" as soon as you start. This will enable additional
  integrity checks on this file to make sure you fill everything out properly.
  If you are a student, we cannot accept your work as finished unless curated is
  set to true.
upvotes_instructions: |
  For the first round, ignore this upvotes number.

  For the second round of reviewing, you will be giving a certain amount of
  upvotes to each vulnerability you see. Your peers will tell you how
  interesting they think this vulnerability is, and you'll add that to the
  upvotes score on your branch.
announced_instructions: |
  Was there a date that this vulnerability was announced to the world? You can
  find this in changelogs, blogs, bug reports, or perhaps the CVE date. A good
  source for this is Chrome's Stable Release Channel
  (https://chromereleases.googleblog.com/).
  Please enter your date in YYYY-MM-DD format.
fixes_vcc_instructions: |
  Please put the commit hash in "commit" below (see my example in
  CVE-2011-3092.yml). Fixes and VCCs follow the same format.
description_instructions: |
  You can get an initial description from the CVE entry on cve.mitre.org. These
  descriptions are a fine start, but they can be kind of jargony.

  Rewrite this description in your own words. Make it interesting and easy to
  read to anyone with some programming experience. We can always pull up the NVD
  description later to get more technical.

  Try to still be specific in your description, but remove Chromium-specific
  stuff. Remove references to versions, specific filenames, and other jargon
  that outsiders to Chromium would not understand. Technology like "regular
  expressions" is fine, and security phrases like "invalid write" are fine to
  keep too.