In the Linux kernel, the following vulnerability has been resolved:
jbd2: fix integer underflow in jbd2_journal_initialize_fast_commit()
jbd2_journal_initialize_fast_commit() validates journal capacity by
checking (journal->j_last - num_fc_blks < JBD2_MIN_JOURNAL_BLOCKS). Both j_last and num_fc_blks are unsigned, so when num_fc_blks exceeds
j_last the subtraction wraps to a large value, bypassing the bounds
check. The resulting underflow corrupts j_last, j_fc_first, and j_free,
leading to journal abort.
Fix by checking num_fc_blks against j_last before the subtraction,
returning -EFSCORRUPTED.
Attack Parameters
Attack Vector
Local
Requires local access
Attack Complexity
Low
Easy to exploit
Privileges Required
Low
Basic privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
High
Complete data leak
Integrity
High
Complete data modification
Availability
High
Complete denial of service
CVSS Vector v3.1
References 8
https://git.kernel.org/stable/c/289a2ca0c9b7eae74f93fc213b0b971669b8683d
416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/4450dcaadf7d4aae8b6e4223b5d6ee4eb77097a9
416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/4b48dcb88bb9117e3d3f051175a9a8b7cff7f8b6
416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/78955fdce8ff654e6d33a2fa90882a1e7eb26330
416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/a58fc10adf503969fec2007b5afe8987258046c4
416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/e144ad0250f77e23e28949587b8b57e40dc3b512
416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/fb9b49618ed7296ebfad62a3835da8945f727001
416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/aa90f00932bf572d6ef284c977c2a60b39c13bd6
416baaa9-dc9f-4396-8d5f-8c081fb06d67