Bug 2401544 (CVE-2023-53616)

Summary: CVE-2023-53616 kernel: jfs: fix invalid free of JFS_IP(ipimap)->i_imap in diUnmount
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: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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A double-free vulnerability was found in the Linux kernel JFS filesystem's inode map cleanup. A local user with privileges to mount filesystems can mount a JFS filesystem, perform a remount operation that fails after freeing internal structures, then unmount the filesystem, causing the cleanup code to free the same memory twice, which results in memory corruption and denial of service through kernel crash.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2025-10-04 16:06:38 UTC 
In the Linux kernel, the following vulnerability has been resolved:

jfs: fix invalid free of JFS_IP(ipimap)->i_imap in diUnmount

syzbot found an invalid-free in diUnmount:

BUG: KASAN: double-free in slab_free mm/slub.c:3661 [inline]
BUG: KASAN: double-free in __kmem_cache_free+0x71/0x110 mm/slub.c:3674
Free of addr ffff88806f410000 by task syz-executor131/3632

 CPU: 0 PID: 3632 Comm: syz-executor131 Not tainted 6.1.0-rc7-syzkaller-00012-gca57f02295f1 #0
 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
 Call Trace:
  <TASK>
  __dump_stack lib/dump_stack.c:88 [inline]
  dump_stack_lvl+0x1b1/0x28e lib/dump_stack.c:106
  print_address_description+0x74/0x340 mm/kasan/report.c:284
  print_report+0x107/0x1f0 mm/kasan/report.c:395
  kasan_report_invalid_free+0xac/0xd0 mm/kasan/report.c:460
  ____kasan_slab_free+0xfb/0x120
  kasan_slab_free include/linux/kasan.h:177 [inline]
  slab_free_hook mm/slub.c:1724 [inline]
  slab_free_freelist_hook+0x12e/0x1a0 mm/slub.c:1750
  slab_free mm/slub.c:3661 [inline]
  __kmem_cache_free+0x71/0x110 mm/slub.c:3674
  diUnmount+0xef/0x100 fs/jfs/jfs_imap.c:195
  jfs_umount+0x108/0x370 fs/jfs/jfs_umount.c:63
  jfs_put_super+0x86/0x190 fs/jfs/super.c:194
  generic_shutdown_super+0x130/0x310 fs/super.c:492
  kill_block_super+0x79/0xd0 fs/super.c:1428
  deactivate_locked_super+0xa7/0xf0 fs/super.c:332
  cleanup_mnt+0x494/0x520 fs/namespace.c:1186
  task_work_run+0x243/0x300 kernel/task_work.c:179
  exit_task_work include/linux/task_work.h:38 [inline]
  do_exit+0x664/0x2070 kernel/exit.c:820
  do_group_exit+0x1fd/0x2b0 kernel/exit.c:950
  __do_sys_exit_group kernel/exit.c:961 [inline]
  __se_sys_exit_group kernel/exit.c:959 [inline]
  __x64_sys_exit_group+0x3b/0x40 kernel/exit.c:959
  do_syscall_x64 arch/x86/entry/common.c:50 [inline]
  do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
  entry_SYSCALL_64_after_hwframe+0x63/0xcd
[...]

JFS_IP(ipimap)->i_imap is not setting to NULL after free in diUnmount.
If jfs_remount() free JFS_IP(ipimap)->i_imap but then failed at diMount().
JFS_IP(ipimap)->i_imap will be freed once again.
Fix this problem by setting JFS_IP(ipimap)->i_imap to NULL after free.
Comment 1 Alexander B 2025-10-06 12:47:44 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025100435-CVE-2023-53616-9379@gregkh/T