CVE-2023-3397: Linux Kernel: [PATCH] fs/jfs: Add a mutex named txEnd_lmLogClose_mutex to prevent a race condition between txEnd and lmLogClose functions

Syzkaller reported an error "slab-use-after-free Write in txEnd".

crash report：

================================================================== BUG: KASAN: slab-use-after-free in instrument_atomic_write include/linux/instrumented.h:87 [inline] BUG: KASAN: slab-use-after-free in clear_bit include/asm-generic/bitops/instrumented-atomic.h:41 [inline] BUG: KASAN: slab-use-after-free in txEnd+0x2a3/0x5a0 fs/jfs/jfs_txnmgr.c:535 Write of size 8 at addr ffff888021bee840 by task jfsCommit/130

CPU: 3 PID: 130 Comm: jfsCommit Not tainted 6.3.0-rc7-pasta #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd9/0x150 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:319 [inline] print_report+0xc1/0x5e0 mm/kasan/report.c:430 kasan_report+0xc0/0xf0 mm/kasan/report.c:536 check_region_inline mm/kasan/generic.c:181 [inline] kasan_check_range+0x144/0x190 mm/kasan/generic.c:187 instrument_atomic_write include/linux/instrumented.h:87 [inline] clear_bit include/asm-generic/bitops/instrumented-atomic.h:41 [inline] txEnd+0x2a3/0x5a0 fs/jfs/jfs_txnmgr.c:535 txLazyCommit fs/jfs/jfs_txnmgr.c:2679 [inline] jfs_lazycommit+0x75f/0xb10 fs/jfs/jfs_txnmgr.c:2727 kthread+0x2e8/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308 </TASK>

Allocated by task 86743: kasan_save_stack+0x22/0x40 mm/kasan/common.c:45 kasan_set_track+0x25/0x30 mm/kasan/common.c:52 ____kasan_kmalloc mm/kasan/common.c:374 [inline] ____kasan_kmalloc mm/kasan/common.c:333 [inline] __kasan_kmalloc+0xa3/0xb0 mm/kasan/common.c:383 kmalloc include/linux/slab.h:580 [inline] kzalloc include/linux/slab.h:720 [inline] open_inline_log fs/jfs/jfs_logmgr.c:1159 [inline] lmLogOpen+0x562/0x1430 fs/jfs/jfs_logmgr.c:1069 jfs_mount_rw+0x2f6/0x6d0 fs/jfs/jfs_mount.c:257 jfs_fill_super+0xa00/0xd40 fs/jfs/super.c:565 mount_bdev+0x351/0x410 fs/super.c:1380 legacy_get_tree+0x109/0x220 fs/fs_context.c:610 vfs_get_tree+0x8d/0x350 fs/super.c:1510 do_new_mount fs/namespace.c:3042 [inline] path_mount+0x675/0x1e30 fs/namespace.c:3372 do_mount fs/namespace.c:3385 [inline] __do_sys_mount fs/namespace.c:3594 [inline] __se_sys_mount fs/namespace.c:3571 [inline] __x64_sys_mount+0x283/0x300 fs/namespace.c:3571 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Freed by task 16288: kasan_save_stack+0x22/0x40 mm/kasan/common.c:45 kasan_set_track+0x25/0x30 mm/kasan/common.c:52 kasan_save_free_info+0x2b/0x40 mm/kasan/generic.c:521 ____kasan_slab_free mm/kasan/common.c:236 [inline] ____kasan_slab_free+0x13b/0x1a0 mm/kasan/common.c:200 kasan_slab_free include/linux/kasan.h:162 [inline] __cache_free mm/slab.c:3390 [inline] __do_kmem_cache_free mm/slab.c:3577 [inline] __kmem_cache_free+0xcd/0x2c0 mm/slab.c:3584 lmLogClose+0x595/0x720 fs/jfs/jfs_logmgr.c:1461 jfs_umount+0x2ef/0x430 fs/jfs/jfs_umount.c:114 jfs_put_super+0x85/0x1d0 fs/jfs/super.c:194 generic_shutdown_super+0x158/0x480 fs/super.c:500 kill_block_super+0x9b/0xf0 fs/super.c:1407 deactivate_locked_super+0x98/0x160 fs/super.c:331 deactivate_super+0xb1/0xd0 fs/super.c:362 cleanup_mnt+0x2ae/0x3d0 fs/namespace.c:1177 task_work_run+0x168/0x260 kernel/task_work.c:179 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop kernel/entry/common.c:171 [inline] exit_to_user_mode_prepare+0x210/0x240 kernel/entry/common.c:204 __syscall_exit_to_user_mode_work kernel/entry/common.c:286 [inline] syscall_exit_to_user_mode+0x1d/0x50 kernel/entry/common.c:297 do_syscall_64+0x46/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Last potentially related work creation: kasan_save_stack+0x22/0x40 mm/kasan/common.c:45 __kasan_record_aux_stack+0x7b/0x90 mm/kasan/generic.c:491 kvfree_call_rcu+0x70/0xad0 kernel/rcu/tree.c:3327 neigh_destroy+0x431/0x660 net/core/neighbour.c:941 neigh_release include/net/neighbour.h:449 [inline] neigh_cleanup_and_release+0x1f8/0x280 net/core/neighbour.c:103 neigh_periodic_work+0x60c/0xac0 net/core/neighbour.c:1025 process_one_work+0x98a/0x15c0 kernel/workqueue.c:2390 worker_thread+0x669/0x1090 kernel/workqueue.c:2537 kthread+0x2e8/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308

The buggy address belongs to the object at ffff888021bee800 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 64 bytes inside of freed 1024-byte region [ffff888021bee800, ffff888021beec00)

The buggy address belongs to the physical page: page:ffffea000086fb80 refcount:1 mapcount:0 mapping:0000000000000000 flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000000200 ffff888012440700 ffffea0000583ed0 ffffea0000609790 raw: 0000000000000000 ffff888021bee000 0000000100000002 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated prep_new_page mm/page_alloc.c:2553 [inline] get_page_from_freelist+0x119c/0x2d40 mm/page_alloc.c:4326 __alloc_pages+0x1cb/0x4a0 mm/page_alloc.c:5592 __alloc_pages_node include/linux/gfp.h:237 [inline] kmem_getpages mm/slab.c:1360 [inline] cache_grow_begin+0x9b/0x3b0 mm/slab.c:2570 cache_alloc_refill+0x27e/0x380 mm/slab.c:2943 ____cache_alloc mm/slab.c:3019 [inline] ____cache_alloc mm/slab.c:3002 [inline] __do_cache_alloc mm/slab.c:3202 [inline] slab_alloc_node mm/slab.c:3250 [inline] __kmem_cache_alloc_node+0x360/0x3f0 mm/slab.c:3541 __do_kmalloc_node mm/slab_common.c:966 [inline] __kmalloc+0x4e/0x190 mm/slab_common.c:980 kmalloc include/linux/slab.h:584 [inline] kzalloc include/linux/slab.h:720 [inline] ieee802_11_parse_elems_full+0x106/0x1320 net/mac80211/util.c:1609 ieee802_11_parse_elems_crc.constprop.0+0x99/0xd0 net/mac80211/ieee80211_i.h:2265 ieee802_11_parse_elems net/mac80211/ieee80211_i.h:2272 [inline] ieee80211_bss_info_update+0x410/0xb50 net/mac80211/scan.c:212 ieee80211_rx_bss_info net/mac80211/ibss.c:1120 [inline] ieee80211_rx_mgmt_probe_beacon net/mac80211/ibss.c:1609 [inline] ieee80211_ibss_rx_queued_mgmt+0x18b2/0x2d30 net/mac80211/ibss.c:1638 ieee80211_iface_process_skb net/mac80211/iface.c:1583 [inline] ieee80211_iface_work+0xa47/0xd60 net/mac80211/iface.c:1637 process_one_work+0x98a/0x15c0 kernel/workqueue.c:2390 worker_thread+0x669/0x1090 kernel/workqueue.c:2537 kthread+0x2e8/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308 page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1454 [inline] free_pcp_prepare+0x4e3/0x920 mm/page_alloc.c:1504 free_unref_page_prepare mm/page_alloc.c:3388 [inline] free_unref_page+0x1d/0x4e0 mm/page_alloc.c:3483 slab_destroy mm/slab.c:1613 [inline] slabs_destroy+0x85/0xc0 mm/slab.c:1633 __cache_free_alien mm/slab.c:773 [inline] cache_free_alien mm/slab.c:789 [inline] ___cache_free+0x203/0x3e0 mm/slab.c:3417 qlink_free mm/kasan/quarantine.c:168 [inline] qlist_free_all+0x4f/0x1a0 mm/kasan/quarantine.c:187 kasan_quarantine_reduce+0x188/0x1d0 mm/kasan/quarantine.c:294 __kasan_slab_alloc+0x63/0x90 mm/kasan/common.c:305 kasan_slab_alloc include/linux/kasan.h:186 [inline] slab_post_alloc_hook mm/slab.h:769 [inline] slab_alloc_node mm/slab.c:3257 [inline] slab_alloc mm/slab.c:3266 [inline] __kmem_cache_alloc_lru mm/slab.c:3443 [inline] kmem_cache_alloc+0x1bd/0x3f0 mm/slab.c:3452 vm_area_alloc+0x20/0x100 kernel/fork.c:458 mmap_region+0x389/0x2270 mm/mmap.c:2553 do_mmap+0x853/0xf20 mm/mmap.c:1364 vm_mmap_pgoff+0x1af/0x280 mm/util.c:542 ksys_mmap_pgoff+0x41f/0x5a0 mm/mmap.c:1410 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Memory state around the buggy address: ffff888021bee700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888021bee780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc

ffff888021bee800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888021bee880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888021bee900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================

Through analysis, it was found that a race condition occurred between two functions lmLogClose and txEnd, which were executed in different threads. The possible sequence is as follows:

---

cpu1(free thread) | cpu2(use thread)

lmLogClose | txEnd | log = JFS_SBI(tblk->sb)->log; sbi->log = NULL; | kfree(log); [1] free log | | clear_bit(log_FLUSH, &log->flag); [2] UAF

Fix it by add a mutex lock between lmLogClose and txEnd:

Fixes: 1da177e4c3f4 (“Linux-2.6.12-rc2”) Signed-off-by: Zheng Wang zyytlz.wz@xxxxxxx

---

fs/jfs/jfs_debug.c | 1 + fs/jfs/jfs_debug.h | 1 + fs/jfs/jfs_logmgr.c | 2 ++ fs/jfs/jfs_txnmgr.c | 8 ++++++++ 4 files changed, 12 insertions(+)

diff --git a/fs/jfs/jfs_debug.c b/fs/jfs/jfs_debug.c index 44b62b3c322e…a9c9266b222b 100644 — a/fs/jfs/jfs_debug.c +++ b/fs/jfs/jfs_debug.c @@ -78,3 +78,4 @@ void jfs_proc_clean(void) }

#endif /* PROC_FS_JFS */ +DEFINE_MUTEX(txEnd_lmLogClose_mutex); \ No newline at end of file diff --git a/fs/jfs/jfs_debug.h b/fs/jfs/jfs_debug.h index 48e2150c092e…25da8ee71f5e 100644 — a/fs/jfs/jfs_debug.h +++ b/fs/jfs/jfs_debug.h @@ -107,3 +107,4 @@ int jfs_xtstat_proc_show(struct seq_file *m, void *v); #endif /* CONFIG_JFS_STATISTICS */

#endif /* _H_JFS_DEBUG */ +extern struct mutex txEnd_lmLogClose_mutex; \ No newline at end of file diff --git a/fs/jfs/jfs_logmgr.c b/fs/jfs/jfs_logmgr.c index 695415cbfe98…05c5391075db 100644 — a/fs/jfs/jfs_logmgr.c +++ b/fs/jfs/jfs_logmgr.c @@ -1442,6 +1442,7 @@ int lmLogClose(struct super_block *sb) jfs_info("lmLogClose: log:0x%p", log);

mutex\_lock(&jfs\_log\_mutex);

• mutex_lock(&txEnd_lmLogClose_mutex); LOG_LOCK(log); list_del(&sbi->log_list); LOG_UNLOCK(log); @@ -1490,6 +1491,7 @@ int lmLogClose(struct super_block *sb) kfree(log);

  out:

• mutex_unlock(&txEnd_lmLogClose_mutex); mutex_unlock(&jfs_log_mutex); jfs_info("lmLogClose: exit(%d)", rc); return rc; diff --git a/fs/jfs/jfs_txnmgr.c b/fs/jfs/jfs_txnmgr.c index ffd4feece078…5b4351e59535 100644 — a/fs/jfs/jfs_txnmgr.c +++ b/fs/jfs/jfs_txnmgr.c @@ -490,6 +490,7 @@ void txEnd(tid_t tid) struct jfs_log *log;

  jfs_info("txEnd: tid = %d", tid);

• mutex_lock(&txEnd_lmLogClose_mutex); TXN_LOCK();

  /* @@ -500,6 +501,11 @@ void txEnd(tid_t tid)

  log = JFS_SBI(tblk->sb)->log;

• if (!log) {

•   mutex\_unlock(&txEnd\_lmLogClose\_mutex);
  

•   return;
  

• }

• /* * Lazy commit thread can’t free this guy until we mark it UNLOCKED, * otherwise, we would be left with a transaction that may have been @@ -515,6 +521,7 @@ void txEnd(tid_t tid) spin_lock_irq(&log->gclock); // LOGGC_LOCK tblk->flag |= tblkGC_UNLOCKED; spin_unlock_irq(&log->gclock); // LOGGC_UNLOCK

•   mutex\_unlock(&txEnd\_lmLogClose\_mutex);
    return;
  

  }

@@ -561,6 +568,7 @@ void txEnd(tid_t tid) * wakeup all waitors for a free tblock */ TXN_WAKEUP(&TxAnchor.freewait);

• mutex_unlock(&txEnd_lmLogClose_mutex); }

/*

2.25.1