linux-kernel - KASAN: slab-use-after-free Read in __list_add_valid_or

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Message-ID:
	<TYSPR06MB71587CEA59B76B2413940A6FF68D2@TYSPR06MB7158.apcprd06.prod.outlook.com>
Date: Fri, 2 May 2025 05:04:24 +0000
From: "huk23@...udan.edu.cn" <huk23@...udan.edu.cn>
To: Andrew Morton <akpm@...ux-foundation.org>
CC: "syzkaller@...glegroups.com" <syzkaller@...glegroups.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"jjtan24@...udan.edu.cn" <jjtan24@...udan.edu.cn>, 白烁冉
	<baishuoran@...eu.edu.cn>
Subject: KASAN: slab-use-after-free Read in __list_add_valid_or_report

Dear Maintainers,




When using our customized Syzkaller to fuzz the latest Linux kernel, the following crash (67th)was triggered.





HEAD commit: 6537cfb395f352782918d8ee7b7f10ba2cc3cbf2
git tree: upstream
Output:https://github.com/pghk13/Kernel-Bug/blob/main/0219_6.13rc7_todo/67-KASAN_%20slab-use-after-free%20Read%20in%20cd_forget/67call_trace.txt
Kernel config:https://github.com/pghk13/Kernel-Bug/blob/main/config.txt
C reproducer:https:https://github.com/pghk13/Kernel-Bug/blob/main/0219_6.13rc7_todo/67-KASAN_%20slab-use-after-free%20Read%20in%20cd_forget/67repro.c
Syzlang reproducer:https://github.com/pghk13/Kernel-Bug/blob/main/0219_6.13rc7_todo/67-KASAN_%20slab-use-after-free%20Read%20in%20cd_forget/67repro.txt

The problem may arise in the __list_add_valid_or_report function, which tries to read the freed memory address ffff888012acfc20. An NTFS inode was assigned, which was later released.
However, in another process, an attempt is made to access a linked list containing a pointer to the released inode via a chrdev_open function. When __list_add_valid_or_report function verifies the integrity of the linked list, it accesses the memory that has been freed.
We have reproduced this issue several times on 6.15-rc1 again.






If you fix this issue, please add the following tag to the commit:
Reported-by: Kun Hu <huk23@...udan.edu.cn>, Jiaji Qin <jjtan24@...udan.edu.cn>, Shuoran Bai <baishuoran@...eu.edu.cn>

==================================================================
BUG: KASAN: slab-use-after-free in __list_add_valid_or_report+0x16a/0x1a0
Read of size 8 at addr ffff888012acfc20 by task syz-executor311/9489

CPU: 0 UID: 0 PID: 9489 Comm: syz-executor311 Not tainted 6.15.0-rc1 #1 PREEMPT(full)
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0x116/0x1b0
 print_report+0xc1/0x630
 kasan_report+0x96/0xd0
 __list_add_valid_or_report+0x16a/0x1a0
 chrdev_open+0x3a7/0x590
 do_dentry_open+0x786/0x1c90
 vfs_open+0x82/0x3f0
 path_openat+0x1f75/0x2980
 do_filp_open+0x1f9/0x2f0
 do_sys_openat2+0x4e3/0x710
 do_sys_open+0xc6/0x150
 __x64_sys_openat+0x9d/0x110
 do_syscall_64+0xcf/0x260
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe80723d76d
Code: c3 e8 17 2d 00 00 0f 1f 80 00 00 00 00 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffe67327788 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0030656c69662f2e RCX: 00007fe80723d76d
RDX: 0000000000000000 RSI: 0000000020002140 RDI: ffffffffffffff9c
RBP: 0000000000000003 R08: 00007ffe67327ca9 R09: 00007ffe67327ca9
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe673277ac
R13: 00007ffe673277d0 R14: 00007ffe673277b0 R15: 0000000000000001
 </TASK>

Allocated by task 9483:
 kasan_save_stack+0x24/0x50
 kasan_save_track+0x14/0x30
 __kasan_slab_alloc+0x87/0x90
 kmem_cache_alloc_lru_noprof+0x165/0x4a0
 ntfs_alloc_inode+0x27/0x80
 alloc_inode+0x67/0x1f0
 new_inode+0x16/0x40
 ntfs_new_inode+0x44/0x110
 ntfs_create_inode+0x3e5/0x4200
 ntfs_mknod+0x3c/0x50
 vfs_mknod+0x5f3/0x900
 do_mknodat+0x377/0x540
 __x64_sys_mknodat+0xb0/0xe0
 do_syscall_64+0xcf/0x260
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 15:
 kasan_save_stack+0x24/0x50
 kasan_save_track+0x14/0x30
 kasan_save_free_info+0x3a/0x60
 __kasan_slab_free+0x54/0x70
 kmem_cache_free+0x14d/0x550
 i_callback+0x46/0x70
 rcu_core+0x7a4/0x1660
 handle_softirqs+0x1be/0x850
 run_ksoftirqd+0x3a/0x60
 smpboot_thread_fn+0x3d2/0xaa0
 kthread+0x447/0x8a0
 ret_from_fork+0x48/0x80
 ret_from_fork_asm+0x1a/0x30

Last potentially related work creation:
 kasan_save_stack+0x24/0x50
 kasan_record_aux_stack+0xb0/0xc0
 __call_rcu_common.constprop.0+0x99/0x820
 destroy_inode+0x12b/0x1b0
 evict+0x4d2/0x830
 iput+0x513/0x820
 dentry_unlink_inode+0x2cd/0x4c0
 __dentry_kill+0x186/0x5b0
 shrink_dentry_list+0x13d/0x650
 shrink_dcache_parent+0x1c4/0x590
 do_one_tree+0x11/0x50
 shrink_dcache_for_umount+0x95/0x1c0
 generic_shutdown_super+0x6c/0x390
 kill_block_super+0x3b/0x90
 ntfs3_kill_sb+0x40/0xf0
 deactivate_locked_super+0xbb/0x130
 deactivate_super+0xb1/0xd0
 cleanup_mnt+0x378/0x510
 task_work_run+0x172/0x280
 syscall_exit_to_user_mode+0x29e/0x2a0
 do_syscall_64+0xdc/0x260
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888012acf580
 which belongs to the cache ntfs_inode_cache of size 1752
The buggy address is located 1696 bytes inside of
 freed 1752-byte region [ffff888012acf580, ffff888012acfc58)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x12ac8
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff88801f47ab01
flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88801f352c80 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000110011 00000000f5000000 ffff88801f47ab01
head: 00fff00000000040 ffff88801f352c80 dead000000000122 0000000000000000
head: 0000000000000000 0000000000110011 00000000f5000000 ffff88801f47ab01
head: 00fff00000000003 ffffea00004ab201 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Reclaimable, gfp_mask 0xd2050(__GFP_RECLAIMABLE|__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 9483, tgid 9483 (syz-executor311), ts 123154831134, free_ts 103166767187
 prep_new_page+0x1b0/0x1e0
 get_page_from_freelist+0x1649/0x30f0
 __alloc_frozen_pages_noprof+0x2fd/0x6d0
 alloc_pages_mpol+0x209/0x550
 new_slab+0x24b/0x340
 ___slab_alloc+0xf0c/0x17c0
 __slab_alloc.isra.0+0x56/0xb0
 kmem_cache_alloc_lru_noprof+0x272/0x4a0
 ntfs_alloc_inode+0x27/0x80
 alloc_inode+0x67/0x1f0
 iget5_locked+0x5f/0xa0
 ntfs_iget5+0xda/0x3a10
 ntfs_fill_super+0x1abd/0x3f10
 get_tree_bdev_flags+0x38a/0x620
 vfs_get_tree+0x93/0x340
 path_mount+0x1270/0x1b90
page last free pid 6892 tgid 6892 stack trace:
 __free_frozen_pages+0x7cd/0x1320
 __put_partials+0x14c/0x170
 qlist_free_all+0x50/0x130
 kasan_quarantine_reduce+0x168/0x1c0
 __kasan_slab_alloc+0x67/0x90
 __kmalloc_noprof+0x1c8/0x600
 tomoyo_realpath_from_path+0xc3/0x600
 tomoyo_path_perm+0x235/0x440
 security_inode_getattr+0x122/0x2b0
 vfs_getattr+0x26/0x70
 vfs_fstat+0x50/0xa0
 __do_sys_newfstat+0x83/0x100
 do_syscall_64+0xcf/0x260
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff888012acfb00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888012acfb80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888012acfc00: fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc fc
                              ^
 ffff888012acfc80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888012acfd00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================



thanks,
Kun Hu