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Re: CVE Request: Ruby safe level bypasses
From: Tyler Hicks <tyhicks () canonical com>
Date: Wed, 3 Oct 2012 13:30:56 -0700

On 2012-10-03 13:48:14, Kurt Seifried wrote:
On 10/02/2012 04:32 PM, Tyler Hicks wrote:
Hello - Upstream Ruby has fixed[1] exception methods that
incorrectly allowed safe level bypasses. These bypasses allowed
untainted strings to be modified by untrusted code in safe level
4.

Note that the changes to exc_to_s() and name_err_to_s(), in
error.c, are similar to the fix for CVE-2011-1005, but the Ruby
advisory[2] made it clear that Ruby 1.9.x was not affected by
CVE-2011-1005. It turns out that the vulnerability was later
reintroduced to Ruby's trunk in revision 29456. Ruby 1.9.3-p0 and
later is affected.

While Shugo Maeda was fixing the issue above, he noticed that 
name_err_mesg_to_str() had a similar flaw. Ruby 1.8.x, along with 
1.9.3-p0 and later is affected.

I believe that these issues need two separate CVEs. Both issues
are fixed in the same upstream patch[1]. Could you please allocate
ids?

Thanks, Tyler

[1]
http://svn.ruby-lang.org/cgi-bin/viewvc.cgi?view=revision&revision=37068


[2]
http://www.ruby-lang.org/en/news/2011/02/18/exception-methods-can-bypass-safe/


Please use CVE-2012-4464 for this issue.

Hi Kurt - I think that two CVE ids are needed here.

All issues are fixed in the same upstream patch but some issues in that
patch affect different versions. I'll use the notation from "CVE
Abstraction Content Decisions: Rationale and Application" to describe
how I see it:

S1: The vulnerability found in exc_to_s()
S2: The vulnerability found in name_err_to_s()
S3: The vulnerability found in name_err_mesg_to_str()

S1, S2 and S3 are the same type of bug. S1 and S2 appear in the same
versions (1.9.3-p0 and newer), so MERGE them. S3 appears in 1.8.x, as
well as 1.9.3-p0 and newer, so SPLIT it from S1 and S2.

Tyler

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