Bug 2320532 (CVE-2024-49957)

Summary: CVE-2024-49957 kernel: ocfs2: fix null-ptr-deref when journal load failed.
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Priority: medium    
Version: unspecifiedCC: dfreiber, drow, jburrell, vkumar
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Hardware: All   
OS: Linux   
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Bug Depends On: 2321064    
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Description OSIDB Bzimport 2024-10-21 19:08:49 UTC 
In the Linux kernel, the following vulnerability has been resolved:

ocfs2: fix null-ptr-deref when journal load failed.

During the mounting process, if journal_reset() fails because of too short
journal, then lead to jbd2_journal_load() fails with NULL j_sb_buffer. 
Subsequently, ocfs2_journal_shutdown() calls
jbd2_journal_flush()->jbd2_cleanup_journal_tail()->
__jbd2_update_log_tail()->jbd2_journal_update_sb_log_tail()
->lock_buffer(journal->j_sb_buffer), resulting in a null-pointer
dereference error.

To resolve this issue, we should check the JBD2_LOADED flag to ensure the
journal was properly loaded.  Additionally, use journal instead of
osb->journal directly to simplify the code.
Comment 1 Robb Gatica 2024-10-22 16:51:26 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2024102131-CVE-2024-49957-3302@gregkh/T