Hello. We are Ubisectech Sirius Team, the vulnerability lab of China ValiantSec. Recently, our team has discovered a issue in Linux kernel 6.8. Attached to the email were a PoC file of the issue.
Stack dump: ------------[ cut here ]------------ UBSAN: array-index-out-of-bounds in fs/squashfs/file.c:256:34 index 4294967295 is out of range for type 'meta_entry [127]' CPU: 1 PID: 16927 Comm: syz-executor.0 Not tainted 6.8.0 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x136/0x150 lib/dump_stack.c:106 ubsan_epilogue lib/ubsan.c:217 [inline] __ubsan_handle_out_of_bounds+0xd5/0x130 lib/ubsan.c:347 fill_meta_index fs/squashfs/file.c:256 [inline] read_blocklist+0x175e/0x1790 fs/squashfs/file.c:333 squashfs_readahead+0x14fa/0x22d0 fs/squashfs/file.c:591 read_pages+0x1a2/0xd70 mm/readahead.c:160 page_cache_ra_unbounded+0x477/0x5f0 mm/readahead.c:269 do_page_cache_ra mm/readahead.c:299 [inline] page_cache_ra_order+0x772/0xa00 mm/readahead.c:544 do_sync_mmap_readahead mm/filemap.c:3153 [inline] filemap_fault+0x1691/0x3390 mm/filemap.c:3245 __do_fault+0x108/0x490 mm/memory.c:4396 do_read_fault mm/memory.c:4758 [inline] do_fault mm/memory.c:4888 [inline] do_pte_missing mm/memory.c:3745 [inline] handle_pte_fault mm/memory.c:5164 [inline] __handle_mm_fault+0x340a/0x48b0 mm/memory.c:5305 handle_mm_fault+0x3c2/0xa40 mm/memory.c:5470 do_user_addr_fault+0x2ed/0x1010 arch/x86/mm/fault.c:1355 handle_page_fault arch/x86/mm/fault.c:1498 [inline] exc_page_fault+0x99/0x180 arch/x86/mm/fault.c:1554 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:570 RIP: 0033:0x7f8446a28202 Code: 48 63 c3 5b c3 0f 1f 00 f3 0f 1e fa 48 89 7c 24 f0 48 89 74 24 e8 48 89 54 24 e0 48 8b 4c 24 f0 48 8b 54 24 e8 48 8b 74 24 e0 <8b> 41 40 23 81 00 01 00 00 f3 0f 6f 06 c1 e0 06 48 01 d0 0f 11 00 RSP: 002b:00007f8447755018 EFLAGS: 00010212 RAX: 00007f8446a281e0 RBX: 00007f8446bcbf80 RCX: 0000000020ff0000 RDX: 0000000000000000 RSI: 0000000020000000 RDI: 0000000020ff0000 RBP: 00007f8446af14a6 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000020ff0000 R11: 0000000020000000 R12: 0000000000000000 R13: 000000000000000b R14: 00007f8446bcbf80 R15: 00007f8447735000 </TASK> ---[ end trace ]--- Thank you for taking the time to read this email and we look forward to working with you further.
poc.c
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