Bug 164989 - CAN-2005-2099 Destruction of failed keyring oopses
Summary: CAN-2005-2099 Destruction of failed keyring oopses
Alias: None
Product: Fedora
Classification: Fedora
Component: kernel
Version: 4
Hardware: All
OS: Linux
Target Milestone: ---
Assignee: David Howells
QA Contact: Brian Brock
Keywords: Security
Depends On:
TreeView+ depends on / blocked
Reported: 2005-08-03 11:05 UTC by David Howells
Modified: 2007-11-30 22:11 UTC (History)
2 users (show)

Clone Of:
Last Closed: 2005-08-29 13:23:24 UTC

Attachments (Terms of Use)
Fix destruction of uninstantiated keyrings (505 bytes, patch)
2005-08-03 11:07 UTC, David Howells
no flags Details | Diff

Description David Howells 2005-08-03 11:05:20 UTC
From Bugzilla Helper:
User-Agent: Mozilla/5.0 (compatible; Konqueror/3.4; Linux) KHTML/3.4.0 (like Gecko)

Description of problem:
This was found on RHEL-4-pre-U2 and patched there before U2 was frozen. 
If a keyring is not fully instantiated when it is destroyed, the kernel will   
oops when it tries to unlink the keyring name from the name list.   
The problem occurs in three stages:   
 (1) The key allocator initialises the type-specific data to all zeroes. In   
     the case of a keyring, this will become a link in the keyring name list   
     when the keyring is instantiated.   
 (2) If a user (any user) attempts to add a keyring with anything other than   
     an empty payload, the keyring instantiation function will fail with an   
     error and won't add the keyring to the name list.   
 (3) The keyring's destructor then sees that the keyring has a description   
     (name) and tries to remove the keyring from the name list, which oopses   
     because the link pointers are both zero.   

Version-Release number of selected component (if applicable):

How reproducible:

Steps to Reproduce:
1.keyctl add keyring a a @p   

Actual Results:  It oopses on a NULL pointer dereference. 

Expected Results:  It should get EINVAL. 

Additional info:

Comment 1 David Howells 2005-08-03 11:07:59 UTC
Created attachment 117397 [details]
Fix destruction of uninstantiated keyrings

The attached patch fixes destruction of uninstantiated keyrings.

Comment 3 Mark J. Cox 2005-08-10 11:55:49 UTC
We sent this to security@kernel.org on 20050803 and it was fixed upstream 20050804

Comment 4 Dave Jones 2005-08-26 22:09:49 UTC
Is fixed in current updates-testing kernel, will go live soon.

Comment 5 Mark J. Cox 2005-08-29 13:23:24 UTC
         FC3        fixed FEDORA-2005-821 [#164989:CLOSED]
         FC4        fixed FEDORA-2005-820 [#164989:CLOSED]

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