6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Viacheslav Dubeyko slava@dubeyko.com
commit 42520df65bf67189541a425f7d36b0b3e7bd7844 upstream.
The hfsplus_strcasecmp() logic can trigger the issue:
[ 117.317703][ T9855] ================================================================== [ 117.318353][ T9855] BUG: KASAN: slab-out-of-bounds in hfsplus_strcasecmp+0x1bc/0x490 [ 117.318991][ T9855] Read of size 2 at addr ffff88802160f40c by task repro/9855 [ 117.319577][ T9855] [ 117.319773][ T9855] CPU: 0 UID: 0 PID: 9855 Comm: repro Not tainted 6.17.0-rc6 #33 PREEMPT(full) [ 117.319780][ T9855] Hardware name: QEMU Ubuntu 24.04 PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [ 117.319783][ T9855] Call Trace: [ 117.319785][ T9855] <TASK> [ 117.319788][ T9855] dump_stack_lvl+0x1c1/0x2a0 [ 117.319795][ T9855] ? __virt_addr_valid+0x1c8/0x5c0 [ 117.319803][ T9855] ? __pfx_dump_stack_lvl+0x10/0x10 [ 117.319808][ T9855] ? rcu_is_watching+0x15/0xb0 [ 117.319816][ T9855] ? lock_release+0x4b/0x3e0 [ 117.319821][ T9855] ? __kasan_check_byte+0x12/0x40 [ 117.319828][ T9855] ? __virt_addr_valid+0x1c8/0x5c0 [ 117.319835][ T9855] ? __virt_addr_valid+0x4a5/0x5c0 [ 117.319842][ T9855] print_report+0x17e/0x7e0 [ 117.319848][ T9855] ? __virt_addr_valid+0x1c8/0x5c0 [ 117.319855][ T9855] ? __virt_addr_valid+0x4a5/0x5c0 [ 117.319862][ T9855] ? __phys_addr+0xd3/0x180 [ 117.319869][ T9855] ? hfsplus_strcasecmp+0x1bc/0x490 [ 117.319876][ T9855] kasan_report+0x147/0x180 [ 117.319882][ T9855] ? hfsplus_strcasecmp+0x1bc/0x490 [ 117.319891][ T9855] hfsplus_strcasecmp+0x1bc/0x490 [ 117.319900][ T9855] ? __pfx_hfsplus_cat_case_cmp_key+0x10/0x10 [ 117.319906][ T9855] hfs_find_rec_by_key+0xa9/0x1e0 [ 117.319913][ T9855] __hfsplus_brec_find+0x18e/0x470 [ 117.319920][ T9855] ? __pfx_hfsplus_bnode_find+0x10/0x10 [ 117.319926][ T9855] ? __pfx_hfs_find_rec_by_key+0x10/0x10 [ 117.319933][ T9855] ? __pfx___hfsplus_brec_find+0x10/0x10 [ 117.319942][ T9855] hfsplus_brec_find+0x28f/0x510 [ 117.319949][ T9855] ? __pfx_hfs_find_rec_by_key+0x10/0x10 [ 117.319956][ T9855] ? __pfx_hfsplus_brec_find+0x10/0x10 [ 117.319963][ T9855] ? __kmalloc_noprof+0x2a9/0x510 [ 117.319969][ T9855] ? hfsplus_find_init+0x8c/0x1d0 [ 117.319976][ T9855] hfsplus_brec_read+0x2b/0x120 [ 117.319983][ T9855] hfsplus_lookup+0x2aa/0x890 [ 117.319990][ T9855] ? __pfx_hfsplus_lookup+0x10/0x10 [ 117.320003][ T9855] ? d_alloc_parallel+0x2f0/0x15e0 [ 117.320008][ T9855] ? __lock_acquire+0xaec/0xd80 [ 117.320013][ T9855] ? __pfx_d_alloc_parallel+0x10/0x10 [ 117.320019][ T9855] ? __raw_spin_lock_init+0x45/0x100 [ 117.320026][ T9855] ? __init_waitqueue_head+0xa9/0x150 [ 117.320034][ T9855] __lookup_slow+0x297/0x3d0 [ 117.320039][ T9855] ? __pfx___lookup_slow+0x10/0x10 [ 117.320045][ T9855] ? down_read+0x1ad/0x2e0 [ 117.320055][ T9855] lookup_slow+0x53/0x70 [ 117.320065][ T9855] walk_component+0x2f0/0x430 [ 117.320073][ T9855] path_lookupat+0x169/0x440 [ 117.320081][ T9855] filename_lookup+0x212/0x590 [ 117.320089][ T9855] ? __pfx_filename_lookup+0x10/0x10 [ 117.320098][ T9855] ? strncpy_from_user+0x150/0x290 [ 117.320105][ T9855] ? getname_flags+0x1e5/0x540 [ 117.320112][ T9855] user_path_at+0x3a/0x60 [ 117.320117][ T9855] __x64_sys_umount+0xee/0x160 [ 117.320123][ T9855] ? __pfx___x64_sys_umount+0x10/0x10 [ 117.320129][ T9855] ? do_syscall_64+0xb7/0x3a0 [ 117.320135][ T9855] ? entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 117.320141][ T9855] ? entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 117.320145][ T9855] do_syscall_64+0xf3/0x3a0 [ 117.320150][ T9855] ? exc_page_fault+0x9f/0xf0 [ 117.320154][ T9855] entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 117.320158][ T9855] RIP: 0033:0x7f7dd7908b07 [ 117.320163][ T9855] Code: 23 0d 00 f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 08 [ 117.320167][ T9855] RSP: 002b:00007ffd5ebd9698 EFLAGS: 00000202 ORIG_RAX: 00000000000000a6 [ 117.320172][ T9855] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f7dd7908b07 [ 117.320176][ T9855] RDX: 0000000000000009 RSI: 0000000000000009 RDI: 00007ffd5ebd9740 [ 117.320179][ T9855] RBP: 00007ffd5ebda780 R08: 0000000000000005 R09: 00007ffd5ebd9530 [ 117.320181][ T9855] R10: 00007f7dd799bfc0 R11: 0000000000000202 R12: 000055e2008b32d0 [ 117.320184][ T9855] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 [ 117.320189][ T9855] </TASK> [ 117.320190][ T9855] [ 117.351311][ T9855] Allocated by task 9855: [ 117.351683][ T9855] kasan_save_track+0x3e/0x80 [ 117.352093][ T9855] __kasan_kmalloc+0x8d/0xa0 [ 117.352490][ T9855] __kmalloc_noprof+0x288/0x510 [ 117.352914][ T9855] hfsplus_find_init+0x8c/0x1d0 [ 117.353342][ T9855] hfsplus_lookup+0x19c/0x890 [ 117.353747][ T9855] __lookup_slow+0x297/0x3d0 [ 117.354148][ T9855] lookup_slow+0x53/0x70 [ 117.354514][ T9855] walk_component+0x2f0/0x430 [ 117.354921][ T9855] path_lookupat+0x169/0x440 [ 117.355325][ T9855] filename_lookup+0x212/0x590 [ 117.355740][ T9855] user_path_at+0x3a/0x60 [ 117.356115][ T9855] __x64_sys_umount+0xee/0x160 [ 117.356529][ T9855] do_syscall_64+0xf3/0x3a0 [ 117.356920][ T9855] entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 117.357429][ T9855] [ 117.357636][ T9855] The buggy address belongs to the object at ffff88802160f000 [ 117.357636][ T9855] which belongs to the cache kmalloc-2k of size 2048 [ 117.358827][ T9855] The buggy address is located 0 bytes to the right of [ 117.358827][ T9855] allocated 1036-byte region [ffff88802160f000, ffff88802160f40c) [ 117.360061][ T9855] [ 117.360266][ T9855] The buggy address belongs to the physical page: [ 117.360813][ T9855] page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x21608 [ 117.361562][ T9855] head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 [ 117.362285][ T9855] flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff) [ 117.362929][ T9855] page_type: f5(slab) [ 117.363282][ T9855] raw: 00fff00000000040 ffff88801a842f00 ffffea0000932000 dead000000000002 [ 117.364015][ T9855] raw: 0000000000000000 0000000080080008 00000000f5000000 0000000000000000 [ 117.364750][ T9855] head: 00fff00000000040 ffff88801a842f00 ffffea0000932000 dead000000000002 [ 117.365491][ T9855] head: 0000000000000000 0000000080080008 00000000f5000000 0000000000000000 [ 117.366232][ T9855] head: 00fff00000000003 ffffea0000858201 00000000ffffffff 00000000ffffffff [ 117.366968][ T9855] head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008 [ 117.367711][ T9855] page dumped because: kasan: bad access detected [ 117.368259][ T9855] page_owner tracks the page as allocated [ 117.368745][ T9855] page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN1 [ 117.370541][ T9855] post_alloc_hook+0x240/0x2a0 [ 117.370954][ T9855] get_page_from_freelist+0x2101/0x21e0 [ 117.371435][ T9855] __alloc_frozen_pages_noprof+0x274/0x380 [ 117.371935][ T9855] alloc_pages_mpol+0x241/0x4b0 [ 117.372360][ T9855] allocate_slab+0x8d/0x380 [ 117.372752][ T9855] ___slab_alloc+0xbe3/0x1400 [ 117.373159][ T9855] __kmalloc_cache_noprof+0x296/0x3d0 [ 117.373621][ T9855] nexthop_net_init+0x75/0x100 [ 117.374038][ T9855] ops_init+0x35c/0x5c0 [ 117.374400][ T9855] setup_net+0x10c/0x320 [ 117.374768][ T9855] copy_net_ns+0x31b/0x4d0 [ 117.375156][ T9855] create_new_namespaces+0x3f3/0x720 [ 117.375613][ T9855] unshare_nsproxy_namespaces+0x11c/0x170 [ 117.376094][ T9855] ksys_unshare+0x4ca/0x8d0 [ 117.376477][ T9855] __x64_sys_unshare+0x38/0x50 [ 117.376879][ T9855] do_syscall_64+0xf3/0x3a0 [ 117.377265][ T9855] page last free pid 9110 tgid 9110 stack trace: [ 117.377795][ T9855] __free_frozen_pages+0xbeb/0xd50 [ 117.378229][ T9855] __put_partials+0x152/0x1a0 [ 117.378625][ T9855] put_cpu_partial+0x17c/0x250 [ 117.379026][ T9855] __slab_free+0x2d4/0x3c0 [ 117.379404][ T9855] qlist_free_all+0x97/0x140 [ 117.379790][ T9855] kasan_quarantine_reduce+0x148/0x160 [ 117.380250][ T9855] __kasan_slab_alloc+0x22/0x80 [ 117.380662][ T9855] __kmalloc_noprof+0x232/0x510 [ 117.381074][ T9855] tomoyo_supervisor+0xc0a/0x1360 [ 117.381498][ T9855] tomoyo_env_perm+0x149/0x1e0 [ 117.381903][ T9855] tomoyo_find_next_domain+0x15ad/0x1b90 [ 117.382378][ T9855] tomoyo_bprm_check_security+0x11c/0x180 [ 117.382859][ T9855] security_bprm_check+0x89/0x280 [ 117.383289][ T9855] bprm_execve+0x8f1/0x14a0 [ 117.383673][ T9855] do_execveat_common+0x528/0x6b0 [ 117.384103][ T9855] __x64_sys_execve+0x94/0xb0 [ 117.384500][ T9855] [ 117.384706][ T9855] Memory state around the buggy address: [ 117.385179][ T9855] ffff88802160f300: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 117.385854][ T9855] ffff88802160f380: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 117.386534][ T9855] >ffff88802160f400: 00 04 fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 117.387204][ T9855] ^ [ 117.387566][ T9855] ffff88802160f480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 117.388243][ T9855] ffff88802160f500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [ 117.388918][ T9855] ==================================================================
The issue takes place if the length field of struct hfsplus_unistr is bigger than HFSPLUS_MAX_STRLEN. The patch simply checks the length of comparing strings. And if the strings' length is bigger than HFSPLUS_MAX_STRLEN, then it is corrected to this value.
v2 The string length correction has been added for hfsplus_strcmp().
Reported-by: Jiaming Zhang r772577952@gmail.com 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 cc: syzkaller@googlegroups.com Link: https://lore.kernel.org/r/20250919191243.1370388-1-slava@dubeyko.com Signed-off-by: Viacheslav Dubeyko slava@dubeyko.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/hfsplus/unicode.c | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+)
--- a/fs/hfsplus/unicode.c +++ b/fs/hfsplus/unicode.c @@ -40,6 +40,18 @@ int hfsplus_strcasecmp(const struct hfsp p1 = s1->unicode; p2 = s2->unicode;
+ if (len1 > HFSPLUS_MAX_STRLEN) { + len1 = HFSPLUS_MAX_STRLEN; + pr_err("invalid length %u has been corrected to %d\n", + be16_to_cpu(s1->length), len1); + } + + if (len2 > HFSPLUS_MAX_STRLEN) { + len2 = HFSPLUS_MAX_STRLEN; + pr_err("invalid length %u has been corrected to %d\n", + be16_to_cpu(s2->length), len2); + } + while (1) { c1 = c2 = 0;
@@ -74,6 +86,18 @@ int hfsplus_strcmp(const struct hfsplus_ p1 = s1->unicode; p2 = s2->unicode;
+ if (len1 > HFSPLUS_MAX_STRLEN) { + len1 = HFSPLUS_MAX_STRLEN; + pr_err("invalid length %u has been corrected to %d\n", + be16_to_cpu(s1->length), len1); + } + + if (len2 > HFSPLUS_MAX_STRLEN) { + len2 = HFSPLUS_MAX_STRLEN; + pr_err("invalid length %u has been corrected to %d\n", + be16_to_cpu(s2->length), len2); + } + for (len = min(len1, len2); len > 0; len--) { c1 = be16_to_cpu(*p1); c2 = be16_to_cpu(*p2);