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Re: Re: CVE request for Calibre
From: Kurt Seifried <kseifried () redhat com>
Date: Sun, 06 Nov 2011 20:11:50 -0700

On 11/04/2011 02:45 PM, Jason A. Donenfeld wrote:
Just do clarify: Issues 1 through 7.1 (8 issues) were released with the
current version that has been out for quite some time now. These require a
CVE. Issues 8 through 14 are ones introduced only during development and
So to confirm these issues will be assigned a CVE (double checking since
this has been quite the mess):
were not released, and do not need a CVE.

So where does that leave us with the CVEs? Well, there are the issues that
were "released" with a "version" of Calibre, and then the trove of bugs he
introduced in the middle. I'll try to recap and separate which is which:

1. Ability to create root owned directory anywhere. The mount helper calls
mkdir(argv[3], ...).

2. Ability to remove any empty directory on the system.

3. Ability to create user_controlled_dir/.created_by_calibre_mount_helper
anywhere on the filesystem.

4. Ability to delete user_controlled_dir/.created_by_calibre_mount_helper
anywhere on the filesystem.

5. Ability to inject arguments into 'mount' being exec'd. On lines 78, 81,
and 83, the final two arguments to mount are user controlled. On lines
1033, 106, 108, 139, and 141, the last argument to unmount/eject is user
controlled. The "exists()" check can be subverted via race condition or by
creating an existing file in the working directory with a filename equal to
the desired injected argument.

6. Ability to execute any program as root. The mount helper makes use of
execlp on lines 78, 81, 83, 103, 106, 108, 139, and 141, and the first
argument does not start with a / character. Because of this, execlp will
search PATH for the executable to run. PATH is user controlled, and thus it
is trivial to write a program that spawns a shell and give it "mount" as a
filename, and direct PATH to its directory.

7. Ability to mount any device to anywhere. This leads to local root, since
you can mount over /etc/ or /etc/pam.d/ or choose-your-own-adventure.

7.1. Ability to unmount any device.


-- 

-Kurt Seifried / Red Hat Security Response Team


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