hfs/hfsplus: prevent getting negative values of offset/length

The syzbot reported KASAN out-of-bounds issue in
hfs_bnode_move():

[   45.588165][ T9821] hfs: dst 14, src 65536, len -65536
[   45.588895][ T9821] ==================================================================
[   45.590114][ T9821] BUG: KASAN: out-of-bounds in hfs_bnode_move+0xfd/0x140
[   45.591127][ T9821] Read of size 18446744073709486080 at addr ffff888035935400 by task repro/9821
[   45.592207][ T9821]
[   45.592420][ T9821] CPU: 0 UID: 0 PID: 9821 Comm: repro Not tainted 6.16.0-rc7-dirty #42 PREEMPT(full)
[   45.592428][ T9821] Hardware name: QEMU Ubuntu 24.04 PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[   45.592431][ T9821] Call Trace:
[   45.592434][ T9821]  <TASK>
[   45.592437][ T9821]  dump_stack_lvl+0x1c1/0x2a0
[   45.592446][ T9821]  ? __virt_addr_valid+0x1c8/0x5c0
[   45.592454][ T9821]  ? __pfx_dump_stack_lvl+0x10/0x10
[   45.592461][ T9821]  ? rcu_is_watching+0x15/0xb0
[   45.592469][ T9821]  ? lock_release+0x4b/0x3e0
[   45.592476][ T9821]  ? __virt_addr_valid+0x1c8/0x5c0
[   45.592483][ T9821]  ? __virt_addr_valid+0x4a5/0x5c0
[   45.592491][ T9821]  print_report+0x17e/0x7c0
[   45.592497][ T9821]  ? __virt_addr_valid+0x1c8/0x5c0
[   45.592504][ T9821]  ? __virt_addr_valid+0x4a5/0x5c0
[   45.592511][ T9821]  ? __phys_addr+0xd3/0x180
[   45.592519][ T9821]  ? hfs_bnode_move+0xfd/0x140
[   45.592526][ T9821]  kasan_report+0x147/0x180
[   45.592531][ T9821]  ? _printk+0xcf/0x120
[   45.592537][ T9821]  ? hfs_bnode_move+0xfd/0x140
[   45.592544][ T9821]  ? hfs_bnode_move+0xfd/0x140
[   45.592552][ T9821]  kasan_check_range+0x2b0/0x2c0
[   45.592557][ T9821]  ? hfs_bnode_move+0xfd/0x140
[   45.592565][ T9821]  __asan_memmove+0x29/0x70
[   45.592572][ T9821]  hfs_bnode_move+0xfd/0x140
[   45.592580][ T9821]  hfs_brec_remove+0x473/0x560
[   45.592589][ T9821]  hfs_cat_move+0x6fb/0x960
[   45.592598][ T9821]  ? __pfx_hfs_cat_move+0x10/0x10
[   45.592607][ T9821]  ? seqcount_lockdep_reader_access+0x122/0x1c0
[   45.592614][ T9821]  ? lockdep_hardirqs_on+0x9c/0x150
[   45.592631][ T9821]  ? __lock_acquire+0xaec/0xd80
[   45.592641][ T9821]  hfs_rename+0x1dc/0x2d0
[   45.592649][ T9821]  ? __pfx_hfs_rename+0x10/0x10
[   45.592657][ T9821]  vfs_rename+0xac6/0xed0
[   45.592664][ T9821]  ? __pfx_vfs_rename+0x10/0x10
[   45.592670][ T9821]  ? d_alloc+0x144/0x190
[   45.592677][ T9821]  ? bpf_lsm_path_rename+0x9/0x20
[   45.592683][ T9821]  ? security_path_rename+0x17d/0x490
[   45.592691][ T9821]  do_renameat2+0x890/0xc50
[   45.592699][ T9821]  ? __pfx_do_renameat2+0x10/0x10
[   45.592707][ T9821]  ? getname_flags+0x1e5/0x540
[   45.592714][ T9821]  __x64_sys_rename+0x82/0x90
[   45.592720][ T9821]  ? entry_SYSCALL_64_after_hwframe+0x77/0x7f
[   45.592725][ T9821]  do_syscall_64+0xf3/0x3a0
[   45.592741][ T9821]  ? exc_page_fault+0x9f/0xf0
[   45.592748][ T9821]  entry_SYSCALL_64_after_hwframe+0x77/0x7f
[   45.592754][ T9821] RIP: 0033:0x7f7f73fe3fc9
[   45.592760][ T9821] Code: 00 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 48
[   45.592765][ T9821] RSP: 002b:00007ffc7e116cf8 EFLAGS: 00000283 ORIG_RAX: 0000000000000052
[   45.592772][ T9821] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f7f73fe3fc9
[   45.592776][ T9821] RDX: 0000200000000871 RSI: 0000200000000780 RDI: 00002000000003c0
[   45.592781][ T9821] RBP: 00007ffc7e116d00 R08: 0000000000000000 R09: 00007ffc7e116d30
[   45.592784][ T9821] R10: fffffffffffffff0 R11: 0000000000000283 R12: 00005557e81f8250
[   45.592788][ T9821] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
[   45.592795][ T9821]  </TASK>
[   45.592797][ T9821]
[   45.619721][ T9821] The buggy address belongs to the physical page:
[   45.620300][ T9821] page: refcount:1 mapcount:1 mapping:0000000000000000 index:0x559a88174 pfn:0x35935
[   45.621150][ T9821] memcg:ffff88810a1d5b00
[   45.621531][ T9821] anon flags: 0xfff60000020838(uptodate|dirty|lru|owner_2|swapbacked|node=0|zone=1|lastcpupid=0x7ff)
[   45.622496][ T9821] raw: 00fff60000020838 ffffea0000d64d88 ffff888021753e10 ffff888029da0771
[   45.623260][ T9821] raw: 0000000559a88174 0000000000000000 0000000100000000 ffff88810a1d5b00
[   45.624030][ T9821] page dumped because: kasan: bad access detected
[   45.624602][ T9821] page_owner tracks the page as allocated
[   45.625115][ T9821] page last allocated via order 0, migratetype Movable, gfp_mask 0x140dca(GFP_HIGHUSER_MOVABLE|__GFP_ZERO0
[   45.626685][ T9821]  post_alloc_hook+0x240/0x2a0
[   45.627127][ T9821]  get_page_from_freelist+0x2101/0x21e0
[   45.627628][ T9821]  __alloc_frozen_pages_noprof+0x274/0x380
[   45.628154][ T9821]  alloc_pages_mpol+0x241/0x4b0
[   45.628593][ T9821]  vma_alloc_folio_noprof+0xe4/0x210
[   45.629066][ T9821]  folio_prealloc+0x30/0x180
[   45.629487][ T9821]  __handle_mm_fault+0x34bd/0x5640
[   45.629957][ T9821]  handle_mm_fault+0x40e/0x8e0
[   45.630392][ T9821]  do_user_addr_fault+0xa81/0x1390
[   45.630862][ T9821]  exc_page_fault+0x76/0xf0
[   45.631273][ T9821]  asm_exc_page_fault+0x26/0x30
[   45.631712][ T9821] page last free pid 5269 tgid 5269 stack trace:
[   45.632281][ T9821]  free_unref_folios+0xc73/0x14c0
[   45.632740][ T9821]  folios_put_refs+0x55b/0x640
[   45.633177][ T9821]  free_pages_and_swap_cache+0x26d/0x510
[   45.633685][ T9821]  tlb_flush_mmu+0x3a0/0x680
[   45.634105][ T9821]  tlb_finish_mmu+0xd4/0x200
[   45.634525][ T9821]  exit_mmap+0x44c/0xb70
[   45.634914][ T9821]  __mmput+0x118/0x420
[   45.635286][ T9821]  exit_mm+0x1da/0x2c0
[   45.635659][ T9821]  do_exit+0x652/0x2330
[   45.636039][ T9821]  do_group_exit+0x21c/0x2d0
[   45.636457][ T9821]  __x64_sys_exit_group+0x3f/0x40
[   45.636915][ T9821]  x64_sys_call+0x21ba/0x21c0
[   45.637342][ T9821]  do_syscall_64+0xf3/0x3a0
[   45.637756][ T9821]  entry_SYSCALL_64_after_hwframe+0x77/0x7f
[   45.638290][ T9821] page has been migrated, last migrate reason: numa_misplaced
[   45.638956][ T9821]
[   45.639173][ T9821] Memory state around the buggy address:
[   45.639677][ T9821]  ffff888035935300: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[   45.640397][ T9821]  ffff888035935380: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[   45.641117][ T9821] >ffff888035935400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[   45.641837][ T9821]                    ^
[   45.642207][ T9821]  ffff888035935480: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[   45.642929][ T9821]  ffff888035935500: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
[   45.643650][ T9821] ==================================================================

This commit [1] fixes the issue if an offset inside of b-tree node
or length of the request is bigger than b-tree node. However,
this fix is still not ready for negative values
of the offset or length. Moreover, negative values of
the offset or length doesn't make sense for b-tree's
operations. Because we could try to access the memory address
outside of the beginning of memory page's addresses range.
Also, using of negative values make logic very complicated,
unpredictable, and we could access the wrong item(s)
in the b-tree node.

This patch changes b-tree interface by means of converting
signed integer arguments of offset and length on u32 type.
Such conversion has goal to prevent of using negative values
unintentionally or by mistake in b-tree operations.

[1] 'commit a431930c9bac ("hfs: fix slab-out-of-bounds in hfs_bnode_read()")'

Signed-off-by: Viacheslav Dubeyko <slava@dubeyko.com>
cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
cc: Yangtao Li <frank.li@vivo.com>
cc: linux-fsdevel@vger.kernel.org
Link: https://lore.kernel.org/r/20251002200020.2578311-1-slava@dubeyko.com
Signed-off-by: Viacheslav Dubeyko <slava@dubeyko.com>

0 files changed, 0 insertions, 0 deletions