fs/ntfs3: Validate buffer length while parsing index

In the Linux kernel, the following vulnerability has been resolved:

fs/ntfs3: Validate buffer length while parsing index

indx_read is called when we have some NTFS directory operations that
need more information from the index buffers. This adds a sanity check
to make sure the returned index buffer length is legit, or we may have
some out-of-bound memory accesses.

[ 560.897595] BUG: KASAN: slab-out-of-bounds in hdr_find_e.isra.0+0x10c/0x320
[ 560.898321] Read of size 2 at addr ffff888009497238 by task exp/245
[ 560.898760]
[ 560.899129] CPU: 0 PID: 245 Comm: exp Not tainted 6.0.0-rc6 #37
[ 560.899505] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
[ 560.900170] Call Trace:
[ 560.900407] <TASK>
[ 560.900732] dump_stack_lvl+0x49/0x63
[ 560.901108] print_report.cold+0xf5/0x689
[ 560.901395] ? hdr_find_e.isra.0+0x10c/0x320
[ 560.901716] kasan_report+0xa7/0x130
[ 560.901950] ? hdr_find_e.isra.0+0x10c/0x320
[ 560.902208] __asan_load2+0x68/0x90
[ 560.902427] hdr_find_e.isra.0+0x10c/0x320
[ 560.902846] ? cmp_uints+0xe0/0xe0
[ 560.903363] ? cmp_sdh+0x90/0x90
[ 560.903883] ? ntfs_bread_run+0x190/0x190
[ 560.904196] ? rwsem_down_read_slowpath+0x750/0x750
[ 560.904969] ? ntfs_fix_post_read+0xe0/0x130
[ 560.905259] ? __kasan_check_write+0x14/0x20
[ 560.905599] ? up_read+0x1a/0x90
[ 560.905853] ? indx_read+0x22c/0x380
[ 560.906096] indx_find+0x2ef/0x470
[ 560.906352] ? indx_find_buffer+0x2d0/0x2d0
[ 560.906692] ? __kasan_kmalloc+0x88/0xb0
[ 560.906977] dir_search_u+0x196/0x2f0
[ 560.907220] ? ntfs_nls_to_utf16+0x450/0x450
[ 560.907464] ? __kasan_check_write+0x14/0x20
[ 560.907747] ? mutex_lock+0x8f/0xe0
[ 560.907970] ? __mutex_lock_slowpath+0x20/0x20
[ 560.908214] ? kmem_cache_alloc+0x143/0x4b0
[ 560.908459] ntfs_lookup+0xe0/0x100
[ 560.908788] __lookup_slow+0x116/0x220
[ 560.909050] ? lookup_fast+0x1b0/0x1b0
[ 560.909309] ? lookup_fast+0x13f/0x1b0
[ 560.909601] walk_component+0x187/0x230
[ 560.909944] link_path_walk.part.0+0x3f0/0x660
[ 560.910285] ? handle_lookup_down+0x90/0x90
[ 560.910618] ? path_init+0x642/0x6e0
[ 560.911084] ? percpu_counter_add_batch+0x6e/0xf0
[ 560.912559] ? __alloc_file+0x114/0x170
[ 560.913008] path_openat+0x19c/0x1d10
[ 560.913419] ? getname_flags+0x73/0x2b0
[ 560.913815] ? kasan_save_stack+0x3a/0x50
[ 560.914125] ? kasan_save_stack+0x26/0x50
[ 560.914542] ? __kasan_slab_alloc+0x6d/0x90
[ 560.914924] ? kmem_cache_alloc+0x143/0x4b0
[ 560.915339] ? getname_flags+0x73/0x2b0
[ 560.915647] ? getname+0x12/0x20
[ 560.916114] ? __x64_sys_open+0x4c/0x60
[ 560.916460] ? path_lookupat.isra.0+0x230/0x230
[ 560.916867] ? __isolate_free_page+0x2e0/0x2e0
[ 560.917194] do_filp_open+0x15c/0x1f0
[ 560.917448] ? may_open_dev+0x60/0x60
[ 560.917696] ? expand_files+0xa4/0x3a0
[ 560.917923] ? __kasan_check_write+0x14/0x20
[ 560.918185] ? _raw_spin_lock+0x88/0xdb
[ 560.918409] ? _raw_spin_lock_irqsave+0x100/0x100
[ 560.918783] ? _find_next_bit+0x4a/0x130
[ 560.919026] ? _raw_spin_unlock+0x19/0x40
[ 560.919276] ? alloc_fd+0x14b/0x2d0
[ 560.919635] do_sys_openat2+0x32a/0x4b0
[ 560.920035] ? file_open_root+0x230/0x230
[ 560.920336] ? __rcu_read_unlock+0x5b/0x280
[ 560.920813] do_sys_open+0x99/0xf0
[ 560.921208] ? filp_open+0x60/0x60
[ 560.921482] ? exit_to_user_mode_prepare+0x49/0x180
[ 560.921867] __x64_sys_open+0x4c/0x60
[ 560.922128] do_syscall_64+0x3b/0x90
[ 560.922369] entry_SYSCALL_64_after_hwframe+0x63/0xcd
[ 560.923030] RIP: 0033:0x7f7dff2e4469
[ 560.923681] Code: 00 f3 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 088
[ 560.924451] RSP: 002b:00007ffd41a210b8 EFLAGS: 00000206 ORIG_RAX: 0000000000000002
[ 560.925168] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f7dff2e4469
[ 560.925655] RDX: 0000000000000000 RSI: 0000000000000002 RDI:
---truncated---