kernel/linux.git/fs/hfsplus/bnode.c, branch v6.18.22

hfsplus: return error when node already exists in hfs_bnode_create

2026-02-26T22:58:56+00:00

[ Upstream commit d8a73cc46c8462a969a7516131feb3096f4c49d3 ] When hfs_bnode_create() finds that a node is already hashed (which should not happen in normal operation), it currently returns the existing node without incrementing its reference count. This causes a reference count inconsistency that leads to a kernel panic when the node is later freed in hfs_bnode_put(): kernel BUG at fs/hfsplus/bnode.c:676! BUG_ON(!atomic_read(&node->refcnt)) This scenario can occur when hfs_bmap_alloc() attempts to allocate a node that is already in use (e.g., when node 0's bitmap bit is incorrectly unset), or due to filesystem corruption. Returning an existing node from a create path is not normal operation. Fix this by returning ERR_PTR(-EEXIST) instead of the node when it's already hashed. This properly signals the error condition to callers, which already check for IS_ERR() return values. Reported-by: syzbot+1c8ff72d0cd8a50dfeaa@syzkaller.appspotmail.com Link: https://syzkaller.appspot.com/bug?extid=1c8ff72d0cd8a50dfeaa Link: https://lore.kernel.org/all/784415834694f39902088fa8946850fc1779a318.camel@ibm.com/ Fixes: 634725a92938 ("[PATCH] hfs: cleanup HFS+ prints") Signed-off-by: Shardul Bankar Reviewed-by: Viacheslav Dubeyko Signed-off-by: Viacheslav Dubeyko Link: https://lore.kernel.org/r/20251229204938.1907089-1-shardul.b@mpiricsoftware.com Signed-off-by: Viacheslav Dubeyko Signed-off-by: Sasha Levin

hfsplus: fix missing hfs_bnode_get() in __hfs_bnode_create

2026-01-02T11:56:40+00:00

[ Upstream commit 152af114287851583cf7e0abc10129941f19466a ] When sync() and link() are called concurrently, both threads may enter hfs_bnode_find() without finding the node in the hash table and proceed to create it. Thread A: hfsplus_write_inode() -> hfsplus_write_system_inode() -> hfs_btree_write() -> hfs_bnode_find(tree, 0) -> __hfs_bnode_create(tree, 0) Thread B: hfsplus_create_cat() -> hfs_brec_insert() -> hfs_bnode_split() -> hfs_bmap_alloc() -> hfs_bnode_find(tree, 0) -> __hfs_bnode_create(tree, 0) In this case, thread A creates the bnode, sets refcnt=1, and hashes it. Thread B also tries to create the same bnode, notices it has already been inserted, drops its own instance, and uses the hashed one without getting the node. ``` node2 = hfs_bnode_findhash(tree, cnid); if (!node2) { <- Thread A hash = hfs_bnode_hash(cnid); node->next_hash = tree->node_hash[hash]; tree->node_hash[hash] = node; tree->node_hash_cnt++; } else { <- Thread B spin_unlock(&tree->hash_lock); kfree(node); wait_event(node2->lock_wq, !test_bit(HFS_BNODE_NEW, &node2->flags)); return node2; } ``` However, hfs_bnode_find() requires each call to take a reference. Here both threads end up setting refcnt=1. When they later put the node, this triggers: BUG_ON(!atomic_read(&node->refcnt)) In this scenario, Thread B in fact finds the node in the hash table rather than creating a new one, and thus must take a reference. Fix this by calling hfs_bnode_get() when reusing a bnode newly created by another thread to ensure the refcount is updated correctly. A similar bug was fixed in HFS long ago in commit a9dc087fd3c4 ("fix missing hfs_bnode_get() in __hfs_bnode_create") but the same issue remained in HFS+ until now. Reported-by: syzbot+005d2a9ecd9fbf525f6a@syzkaller.appspotmail.com Signed-off-by: Yang Chenzhi Signed-off-by: Viacheslav Dubeyko Link: https://lore.kernel.org/r/20250829093912.611853-1-yang.chenzhi@vivo.com Signed-off-by: Viacheslav Dubeyko Signed-off-by: Sasha Levin

hfsplus: fix volume corruption issue for generic/070

2026-01-02T11:56:40+00:00

[ Upstream commit ed490f36f439b877393c12a2113601e4145a5a56 ] The xfstests' test-case generic/070 leaves HFS+ volume in corrupted state: sudo ./check generic/070 FSTYP -- hfsplus PLATFORM -- Linux/x86_64 hfsplus-testing-0001 6.17.0-rc1+ #4 SMP PREEMPT_DYNAMIC Wed Oct 1 15:02:44 PDT 2025 MKFS_OPTIONS -- /dev/loop51 MOUNT_OPTIONS -- /dev/loop51 /mnt/scratch generic/070 _check_generic_filesystem: filesystem on /dev/loop50 is inconsistent (see xfstests-dev/results//generic/070.full for details) Ran: generic/070 Failures: generic/070 Failed 1 of 1 tests sudo fsck.hfsplus -d /dev/loop50 ** /dev/loop50 Using cacheBlockSize=32K cacheTotalBlock=1024 cacheSize=32768K. Executing fsck_hfs (version 540.1-Linux). ** Checking non-journaled HFS Plus Volume. The volume name is test ** Checking extents overflow file. Unused node is not erased (node = 1) ** Checking catalog file. ** Checking multi-linked files. ** Checking catalog hierarchy. ** Checking extended attributes file. ** Checking volume bitmap. ** Checking volume information. Verify Status: VIStat = 0x0000, ABTStat = 0x0000 EBTStat = 0x0004 CBTStat = 0x0000 CatStat = 0x00000000 ** Repairing volume. ** Rechecking volume. ** Checking non-journaled HFS Plus Volume. The volume name is test ** Checking extents overflow file. ** Checking catalog file. ** Checking multi-linked files. ** Checking catalog hierarchy. ** Checking extended attributes file. ** Checking volume bitmap. ** Checking volume information. ** The volume test was repaired successfully. It is possible to see that fsck.hfsplus detected not erased and unused node for the case of extents overflow file. The HFS+ logic has special method that defines if the node should be erased: bool hfs_bnode_need_zeroout(struct hfs_btree *tree) { struct super_block *sb = tree->inode->i_sb; struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb); const u32 volume_attr = be32_to_cpu(sbi->s_vhdr->attributes); return tree->cnid == HFSPLUS_CAT_CNID && volume_attr & HFSPLUS_VOL_UNUSED_NODE_FIX; } However, it is possible to see that this method works only for the case of catalog file. But debugging of the issue has shown that HFSPLUS_VOL_UNUSED_NODE_FIX attribute has been requested for the extents overflow file too: catalog file kernel: hfsplus: node 4, num_recs 0, flags 0x10 kernel: hfsplus: tree->cnid 4, volume_attr 0x80000800 extents overflow file kernel: hfsplus: node 1, num_recs 0, flags 0x10 kernel: hfsplus: tree->cnid 3, volume_attr 0x80000800 This patch modifies the hfs_bnode_need_zeroout() by checking only volume_attr but not the b-tree ID because node zeroing can be requested for all HFS+ b-tree types. sudo ./check generic/070 FSTYP -- hfsplus PLATFORM -- Linux/x86_64 hfsplus-testing-0001 6.18.0-rc3+ #79 SMP PREEMPT_DYNAMIC Fri Oct 31 16:07:42 PDT 2025 MKFS_OPTIONS -- /dev/loop51 MOUNT_OPTIONS -- /dev/loop51 /mnt/scratch generic/070 33s ... 34s Ran: generic/070 Passed all 1 tests Signed-off-by: Viacheslav Dubeyko cc: John Paul Adrian Glaubitz cc: Yangtao Li cc: linux-fsdevel@vger.kernel.org Link: https://lore.kernel.org/r/20251101001229.247432-1-slava@dubeyko.com Signed-off-by: Viacheslav Dubeyko Signed-off-by: Sasha Levin

hfs/hfsplus: rework debug output subsystem

2025-09-24T23:30:34+00:00

Currently, HFS/HFS+ has very obsolete and inconvenient debug output subsystem. Also, the code is duplicated in HFS and HFS+ driver. This patch introduces linux/hfs_common.h for gathering common declarations, inline functions, and common short methods. Currently, this file contains only hfs_dbg() function that employs pr_debug() with the goal to print a debug-level messages conditionally. So, now, it is possible to enable the debug output by means of: echo 'file extent.c +p' > /proc/dynamic_debug/control echo 'func hfsplus_evict_inode +p' > /proc/dynamic_debug/control And debug output looks like this: hfs: pid 5831:fs/hfs/catalog.c:228 hfs_cat_delete(): delete_cat: 00,48 hfs: pid 5831:fs/hfs/extent.c:484 hfs_file_truncate(): truncate: 48, 409600 -> 0 hfs: pid 5831:fs/hfs/extent.c:212 hfs_dump_extent(): hfs: pid 5831:fs/hfs/extent.c:214 hfs_dump_extent(): 78:4 hfs: pid 5831:fs/hfs/extent.c:214 hfs_dump_extent(): 0:0 hfs: pid 5831:fs/hfs/extent.c:214 hfs_dump_extent(): 0:0 v4 Debug messages have been reworked and information about new HFS/HFS+ shared declarations file has been added to MAINTAINERS file. v5 Yangtao Li suggested to clean up debug output and fix several typos. Signed-off-by: Viacheslav Dubeyko cc: John Paul Adrian Glaubitz cc: Yangtao Li cc: linux-fsdevel@vger.kernel.org cc: Johannes Thumshirn Signed-off-by: Viacheslav Dubeyko

hfs: validate record offset in hfsplus_bmap_alloc

2025-09-01T01:09:44+00:00

hfsplus_bmap_alloc can trigger a crash if a record offset or length is larger than node_size [ 15.264282] BUG: KASAN: slab-out-of-bounds in hfsplus_bmap_alloc+0x887/0x8b0 [ 15.265192] Read of size 8 at addr ffff8881085ca188 by task test/183 [ 15.265949] [ 15.266163] CPU: 0 UID: 0 PID: 183 Comm: test Not tainted 6.17.0-rc2-gc17b750b3ad9 #14 PREEMPT(voluntary) [ 15.266165] Hardware name: QEMU Ubuntu 24.04 PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [ 15.266167] Call Trace: [ 15.266168] [ 15.266169] dump_stack_lvl+0x53/0x70 [ 15.266173] print_report+0xd0/0x660 [ 15.266181] kasan_report+0xce/0x100 [ 15.266185] hfsplus_bmap_alloc+0x887/0x8b0 [ 15.266208] hfs_btree_inc_height.isra.0+0xd5/0x7c0 [ 15.266217] hfsplus_brec_insert+0x870/0xb00 [ 15.266222] __hfsplus_ext_write_extent+0x428/0x570 [ 15.266225] __hfsplus_ext_cache_extent+0x5e/0x910 [ 15.266227] hfsplus_ext_read_extent+0x1b2/0x200 [ 15.266233] hfsplus_file_extend+0x5a7/0x1000 [ 15.266237] hfsplus_get_block+0x12b/0x8c0 [ 15.266238] __block_write_begin_int+0x36b/0x12c0 [ 15.266251] block_write_begin+0x77/0x110 [ 15.266252] cont_write_begin+0x428/0x720 [ 15.266259] hfsplus_write_begin+0x51/0x100 [ 15.266262] cont_write_begin+0x272/0x720 [ 15.266270] hfsplus_write_begin+0x51/0x100 [ 15.266274] generic_perform_write+0x321/0x750 [ 15.266285] generic_file_write_iter+0xc3/0x310 [ 15.266289] __kernel_write_iter+0x2fd/0x800 [ 15.266296] dump_user_range+0x2ea/0x910 [ 15.266301] elf_core_dump+0x2a94/0x2ed0 [ 15.266320] vfs_coredump+0x1d85/0x45e0 [ 15.266349] get_signal+0x12e3/0x1990 [ 15.266357] arch_do_signal_or_restart+0x89/0x580 [ 15.266362] irqentry_exit_to_user_mode+0xab/0x110 [ 15.266364] asm_exc_page_fault+0x26/0x30 [ 15.266366] RIP: 0033:0x41bd35 [ 15.266367] Code: bc d1 f3 0f 7f 27 f3 0f 7f 6f 10 f3 0f 7f 77 20 f3 0f 7f 7f 30 49 83 c0 0f 49 29 d0 48 8d 7c 17 31 e9 9f 0b 00 00 66 0f ef c0 0f 6f 0e f3 0f 6f 56 10 66 0f 74 c1 66 0f d7 d0 49 83 f8f [ 15.266369] RSP: 002b:00007ffc9e62d078 EFLAGS: 00010283 [ 15.266371] RAX: 00007ffc9e62d100 RBX: 0000000000000000 RCX: 0000000000000000 [ 15.266372] RDX: 00000000000000e0 RSI: 0000000000000000 RDI: 00007ffc9e62d100 [ 15.266373] RBP: 0000400000000040 R08: 00000000000000e0 R09: 0000000000000000 [ 15.266374] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 [ 15.266375] R13: 0000000000000000 R14: 0000000000000000 R15: 0000400000000000 [ 15.266376] When calling hfsplus_bmap_alloc to allocate a free node, this function first retrieves the bitmap from header node and map node using node->page together with the offset and length from hfs_brec_lenoff ``` len = hfs_brec_lenoff(node, 2, &off16); off = off16; off += node->page_offset; pagep = node->page + (off >> PAGE_SHIFT); data = kmap_local_page(*pagep); ``` However, if the retrieved offset or length is invalid(i.e. exceeds node_size), the code may end up accessing pages outside the allocated range for this node. This patch adds proper validation of both offset and length before use, preventing out-of-bounds page access. Move is_bnode_offset_valid and check_and_correct_requested_length to hfsplus_fs.h, as they may be required by other functions. Reported-by: syzbot+356aed408415a56543cd@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/67bcb4a6.050a0220.bbfd1.008f.GAE@google.com/ Signed-off-by: Yang Chenzhi Reviewed-by: Viacheslav Dubeyko Signed-off-by: Viacheslav Dubeyko Link: https://lore.kernel.org/r/20250818141734.8559-2-yang.chenzhi@vivo.com Signed-off-by: Viacheslav Dubeyko

hfsplus: fix slab-out-of-bounds in hfsplus_bnode_read()

2025-07-25T22:37:12+00:00

The hfsplus_bnode_read() method can trigger the issue: [ 174.852007][ T9784] ================================================================== [ 174.852709][ T9784] BUG: KASAN: slab-out-of-bounds in hfsplus_bnode_read+0x2f4/0x360 [ 174.853412][ T9784] Read of size 8 at addr ffff88810b5fc6c0 by task repro/9784 [ 174.854059][ T9784] [ 174.854272][ T9784] CPU: 1 UID: 0 PID: 9784 Comm: repro Not tainted 6.16.0-rc3 #7 PREEMPT(full) [ 174.854281][ T9784] Hardware name: QEMU Ubuntu 24.04 PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [ 174.854286][ T9784] Call Trace: [ 174.854289][ T9784] [ 174.854292][ T9784] dump_stack_lvl+0x10e/0x1f0 [ 174.854305][ T9784] print_report+0xd0/0x660 [ 174.854315][ T9784] ? __virt_addr_valid+0x81/0x610 [ 174.854323][ T9784] ? __phys_addr+0xe8/0x180 [ 174.854330][ T9784] ? hfsplus_bnode_read+0x2f4/0x360 [ 174.854337][ T9784] kasan_report+0xc6/0x100 [ 174.854346][ T9784] ? hfsplus_bnode_read+0x2f4/0x360 [ 174.854354][ T9784] hfsplus_bnode_read+0x2f4/0x360 [ 174.854362][ T9784] hfsplus_bnode_dump+0x2ec/0x380 [ 174.854370][ T9784] ? __pfx_hfsplus_bnode_dump+0x10/0x10 [ 174.854377][ T9784] ? hfsplus_bnode_write_u16+0x83/0xb0 [ 174.854385][ T9784] ? srcu_gp_start+0xd0/0x310 [ 174.854393][ T9784] ? __mark_inode_dirty+0x29e/0xe40 [ 174.854402][ T9784] hfsplus_brec_remove+0x3d2/0x4e0 [ 174.854411][ T9784] __hfsplus_delete_attr+0x290/0x3a0 [ 174.854419][ T9784] ? __pfx_hfs_find_1st_rec_by_cnid+0x10/0x10 [ 174.854427][ T9784] ? __pfx___hfsplus_delete_attr+0x10/0x10 [ 174.854436][ T9784] ? __asan_memset+0x23/0x50 [ 174.854450][ T9784] hfsplus_delete_all_attrs+0x262/0x320 [ 174.854459][ T9784] ? __pfx_hfsplus_delete_all_attrs+0x10/0x10 [ 174.854469][ T9784] ? rcu_is_watching+0x12/0xc0 [ 174.854476][ T9784] ? __mark_inode_dirty+0x29e/0xe40 [ 174.854483][ T9784] hfsplus_delete_cat+0x845/0xde0 [ 174.854493][ T9784] ? __pfx_hfsplus_delete_cat+0x10/0x10 [ 174.854507][ T9784] hfsplus_unlink+0x1ca/0x7c0 [ 174.854516][ T9784] ? __pfx_hfsplus_unlink+0x10/0x10 [ 174.854525][ T9784] ? down_write+0x148/0x200 [ 174.854532][ T9784] ? __pfx_down_write+0x10/0x10 [ 174.854540][ T9784] vfs_unlink+0x2fe/0x9b0 [ 174.854549][ T9784] do_unlinkat+0x490/0x670 [ 174.854557][ T9784] ? __pfx_do_unlinkat+0x10/0x10 [ 174.854565][ T9784] ? __might_fault+0xbc/0x130 [ 174.854576][ T9784] ? getname_flags.part.0+0x1c5/0x550 [ 174.854584][ T9784] __x64_sys_unlink+0xc5/0x110 [ 174.854592][ T9784] do_syscall_64+0xc9/0x480 [ 174.854600][ T9784] entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 174.854608][ T9784] RIP: 0033:0x7f6fdf4c3167 [ 174.854614][ T9784] Code: f0 ff ff 73 01 c3 48 8b 0d 26 0d 0e 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 08 [ 174.854622][ T9784] RSP: 002b:00007ffcb948bca8 EFLAGS: 00000206 ORIG_RAX: 0000000000000057 [ 174.854630][ T9784] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f6fdf4c3167 [ 174.854636][ T9784] RDX: 00007ffcb948bcc0 RSI: 00007ffcb948bcc0 RDI: 00007ffcb948bd50 [ 174.854641][ T9784] RBP: 00007ffcb948cd90 R08: 0000000000000001 R09: 00007ffcb948bb40 [ 174.854645][ T9784] R10: 00007f6fdf564fc0 R11: 0000000000000206 R12: 0000561e1bc9c2d0 [ 174.854650][ T9784] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 [ 174.854658][ T9784] [ 174.854661][ T9784] [ 174.879281][ T9784] Allocated by task 9784: [ 174.879664][ T9784] kasan_save_stack+0x20/0x40 [ 174.880082][ T9784] kasan_save_track+0x14/0x30 [ 174.880500][ T9784] __kasan_kmalloc+0xaa/0xb0 [ 174.880908][ T9784] __kmalloc_noprof+0x205/0x550 [ 174.881337][ T9784] __hfs_bnode_create+0x107/0x890 [ 174.881779][ T9784] hfsplus_bnode_find+0x2d0/0xd10 [ 174.882222][ T9784] hfsplus_brec_find+0x2b0/0x520 [ 174.882659][ T9784] hfsplus_delete_all_attrs+0x23b/0x320 [ 174.883144][ T9784] hfsplus_delete_cat+0x845/0xde0 [ 174.883595][ T9784] hfsplus_rmdir+0x106/0x1b0 [ 174.884004][ T9784] vfs_rmdir+0x206/0x690 [ 174.884379][ T9784] do_rmdir+0x2b7/0x390 [ 174.884751][ T9784] __x64_sys_rmdir+0xc5/0x110 [ 174.885167][ T9784] do_syscall_64+0xc9/0x480 [ 174.885568][ T9784] entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 174.886083][ T9784] [ 174.886293][ T9784] The buggy address belongs to the object at ffff88810b5fc600 [ 174.886293][ T9784] which belongs to the cache kmalloc-192 of size 192 [ 174.887507][ T9784] The buggy address is located 40 bytes to the right of [ 174.887507][ T9784] allocated 152-byte region [ffff88810b5fc600, ffff88810b5fc698) [ 174.888766][ T9784] [ 174.888976][ T9784] The buggy address belongs to the physical page: [ 174.889533][ T9784] page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x10b5fc [ 174.890295][ T9784] flags: 0x57ff00000000000(node=1|zone=2|lastcpupid=0x7ff) [ 174.890927][ T9784] page_type: f5(slab) [ 174.891284][ T9784] raw: 057ff00000000000 ffff88801b4423c0 ffffea000426dc80 dead000000000002 [ 174.892032][ T9784] raw: 0000000000000000 0000000080100010 00000000f5000000 0000000000000000 [ 174.892774][ T9784] page dumped because: kasan: bad access detected [ 174.893327][ T9784] page_owner tracks the page as allocated [ 174.893825][ T9784] page last allocated via order 0, migratetype Unmovable, gfp_mask 0x52c00(GFP_NOIO|__GFP_NOWARN|__GFP_NO1 [ 174.895373][ T9784] post_alloc_hook+0x1c0/0x230 [ 174.895801][ T9784] get_page_from_freelist+0xdeb/0x3b30 [ 174.896284][ T9784] __alloc_frozen_pages_noprof+0x25c/0x2460 [ 174.896810][ T9784] alloc_pages_mpol+0x1fb/0x550 [ 174.897242][ T9784] new_slab+0x23b/0x340 [ 174.897614][ T9784] ___slab_alloc+0xd81/0x1960 [ 174.898028][ T9784] __slab_alloc.isra.0+0x56/0xb0 [ 174.898468][ T9784] __kmalloc_noprof+0x2b0/0x550 [ 174.898896][ T9784] usb_alloc_urb+0x73/0xa0 [ 174.899289][ T9784] usb_control_msg+0x1cb/0x4a0 [ 174.899718][ T9784] usb_get_string+0xab/0x1a0 [ 174.900133][ T9784] usb_string_sub+0x107/0x3c0 [ 174.900549][ T9784] usb_string+0x307/0x670 [ 174.900933][ T9784] usb_cache_string+0x80/0x150 [ 174.901355][ T9784] usb_new_device+0x1d0/0x19d0 [ 174.901786][ T9784] register_root_hub+0x299/0x730 [ 174.902231][ T9784] page last free pid 10 tgid 10 stack trace: [ 174.902757][ T9784] __free_frozen_pages+0x80c/0x1250 [ 174.903217][ T9784] vfree.part.0+0x12b/0xab0 [ 174.903645][ T9784] delayed_vfree_work+0x93/0xd0 [ 174.904073][ T9784] process_one_work+0x9b5/0x1b80 [ 174.904519][ T9784] worker_thread+0x630/0xe60 [ 174.904927][ T9784] kthread+0x3a8/0x770 [ 174.905291][ T9784] ret_from_fork+0x517/0x6e0 [ 174.905709][ T9784] ret_from_fork_asm+0x1a/0x30 [ 174.906128][ T9784] [ 174.906338][ T9784] Memory state around the buggy address: [ 174.906828][ T9784] ffff88810b5fc580: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc [ 174.907528][ T9784] ffff88810b5fc600: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 174.908222][ T9784] >ffff88810b5fc680: 00 00 00 fc fc fc fc fc fc fc fc fc fc fc fc fc [ 174.908917][ T9784] ^ [ 174.909481][ T9784] ffff88810b5fc700: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [ 174.910432][ T9784] ffff88810b5fc780: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc [ 174.911401][ T9784] ================================================================== The reason of the issue that code doesn't check the correctness of the requested offset and length. As a result, incorrect value of offset or/and length could result in access out of allocated memory. This patch introduces is_bnode_offset_valid() method that checks the requested offset value. Also, it introduces check_and_correct_requested_length() method that checks and correct the requested length (if it is necessary). These methods are used in hfsplus_bnode_read(), hfsplus_bnode_write(), hfsplus_bnode_clear(), hfsplus_bnode_copy(), and hfsplus_bnode_move() with the goal to prevent the access out of allocated memory and triggering the crash. Reported-by: Kun Hu Reported-by: Jiaji Qin Reported-by: Shuoran Bai Signed-off-by: Viacheslav Dubeyko Link: https://lore.kernel.org/r/20250703214804.244077-1-slava@dubeyko.com Signed-off-by: Viacheslav Dubeyko

hfs/hfsplus: fix slab-out-of-bounds in hfs_bnode_read_key

2025-04-07T17:21:51+00:00

Syzbot reported an issue in hfs subsystem: BUG: KASAN: slab-out-of-bounds in memcpy_from_page include/linux/highmem.h:423 [inline] BUG: KASAN: slab-out-of-bounds in hfs_bnode_read fs/hfs/bnode.c:35 [inline] BUG: KASAN: slab-out-of-bounds in hfs_bnode_read_key+0x314/0x450 fs/hfs/bnode.c:70 Write of size 94 at addr ffff8880123cd100 by task syz-executor237/5102 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:377 [inline] print_report+0x169/0x550 mm/kasan/report.c:488 kasan_report+0x143/0x180 mm/kasan/report.c:601 kasan_check_range+0x282/0x290 mm/kasan/generic.c:189 __asan_memcpy+0x40/0x70 mm/kasan/shadow.c:106 memcpy_from_page include/linux/highmem.h:423 [inline] hfs_bnode_read fs/hfs/bnode.c:35 [inline] hfs_bnode_read_key+0x314/0x450 fs/hfs/bnode.c:70 hfs_brec_insert+0x7f3/0xbd0 fs/hfs/brec.c:159 hfs_cat_create+0x41d/0xa50 fs/hfs/catalog.c:118 hfs_mkdir+0x6c/0xe0 fs/hfs/dir.c:232 vfs_mkdir+0x2f9/0x4f0 fs/namei.c:4257 do_mkdirat+0x264/0x3a0 fs/namei.c:4280 __do_sys_mkdir fs/namei.c:4300 [inline] __se_sys_mkdir fs/namei.c:4298 [inline] __x64_sys_mkdir+0x6c/0x80 fs/namei.c:4298 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fbdd6057a99 Add a check for key length in hfs_bnode_read_key to prevent out-of-bounds memory access. If the key length is invalid, the key buffer is cleared, improving stability and reliability. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-by: syzbot+5f3a973ed3dfb85a6683@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=5f3a973ed3dfb85a6683 Cc: stable@vger.kernel.org Signed-off-by: Vasiliy Kovalev Link: https://lore.kernel.org/20241019191303.24048-1-kovalev@altlinux.org Reviewed-by: Cengiz Can Signed-off-by: Christian Brauner

hfsplus: convert kmap() to kmap_local_page() in bnode.c

2022-09-12T04:55:04+00:00

kmap() is being deprecated in favor of kmap_local_page(). Two main problems with kmap(): (1) It comes with an overhead as mapping space is restricted and protected by a global lock for synchronization and (2) it also requires global TLB invalidation when the kmap's pool wraps and it might block when the mapping space is fully utilized until a slot becomes available. With kmap_local_page() the mappings are per thread, CPU local, can take page faults, and can be called from any context (including interrupts). It is faster than kmap() in kernels with HIGHMEM enabled. Furthermore, the tasks can be preempted and, when they are scheduled to run again, the kernel virtual addresses are restored and still valid. Since its use in bnode.c is safe everywhere, it should be preferred. Therefore, replace kmap() with kmap_local_page() in bnode.c. Where possible, use the suited standard helpers (memzero_page(), memcpy_page()) instead of open coding kmap_local_page() plus memset() or memcpy(). Tested in a QEMU/KVM x86_32 VM, 6GB RAM, booting a kernel with HIGHMEM64GB enabled. Link: https://lkml.kernel.org/r/20220809203105.26183-3-fmdefrancesco@gmail.com Signed-off-by: Fabio M. De Francesco Suggested-by: Ira Weiny Reviewed-by: Ira Weiny Reviewed-by: Viacheslav Dubeyko Cc: Bart Van Assche Cc: Jens Axboe Cc: Kees Cook Cc: Matthew Wilcox Cc: Muchun Song Signed-off-by: Andrew Morton

hfsplus: Remove check for PageError

2022-06-29T12:51:06+00:00

If read_mapping_page() encounters an error, it returns an errno, not a page with PageError set, so this is dead code. Signed-off-by: Matthew Wilcox (Oracle)

hfs/hfsplus: clean up unused variables in bnode.c

2017-11-18T00:10:03+00:00

Delete variables 'tree' and 'sb', which are set but never used. Link: http://lkml.kernel.org/r/1507977146-15875-1-git-send-email-chris.gekas@gmail.com Signed-off-by: Christos Gkekas Cc: Christoph Hellwig Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds