Bug 2297535 (CVE-2024-40951)

Summary: CVE-2024-40951 kernel: ocfs2: fix NULL pointer dereference in ocfs2_abort_trigger()
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: dfreiber, drow, jburrell, vkumar
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: kernel 6.6.36, kernel 6.9.7, kernel 6.10-rc5 Doc Type: If docs needed, set a value
Doc Text:
A flaw was found in the Linux kernel. The resolved OCFS2 vulnerability involved a NULL pointer dereference in `ocfs2_abort_trigger()`. The issue arose after `dev ->bd_super` was removed and replaced by `b_assoc_map->host->i_sb`, leading to errors since OCFS2 did not set `bh->b_assoc_map.`
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Description OSIDB Bzimport 2024-07-12 13:39:05 UTC 
In the Linux kernel, the following vulnerability has been resolved:

ocfs2: fix NULL pointer dereference in ocfs2_abort_trigger()

bdev->bd_super has been removed and commit 8887b94d9322 change the usage
from bdev->bd_super to b_assoc_map->host->i_sb.  Since ocfs2 hasn't set
bh->b_assoc_map, it will trigger NULL pointer dereference when calling
into ocfs2_abort_trigger().

Actually this was pointed out in history, see commit 74e364ad1b13.  But
I've made a mistake when reviewing commit 8887b94d9322 and then
re-introduce this regression.

Since we cannot revive bdev in buffer head, so fix this issue by
initializing all types of ocfs2 triggers when fill super, and then get the
specific ocfs2 trigger from ocfs2_caching_info when access journal.

[joseph.qi.com: v2]
  Link: https://lkml.kernel.org/r/20240602112045.1112708-1-joseph.qi@linux.alibaba.com