Date:   Fri, 22 Jul 2022 13:52:01 -0700
From:   Dipanjan Das <mail.dipanjan.das@...il.com>
To:     Matthew Wilcox <willy@...radead.org>,
        damien.lemoal@...nsource.wdc.com, jlayton@...nel.org, jack@...e.cz,
        edward.shishkin@...il.com, reiserfs-devel@...r.kernel.org,
        linux-kernel@...r.kernel.org
Cc:     syzkaller@...glegroups.com, fleischermarius@...glemail.com,
        its.priyanka.bose@...il.com
Subject: KASAN: use-after-free Read in reiserfs_fill_super

Hi,

We would like to report the following bug which has been found by our
modified version of syzkaller.

======================================================
description: KASAN: use-after-free Read in reiserfs_fill_super
affected file: fs/reiserfs/inode.c
kernel version: 5.19-rc6
kernel commit: 32346491ddf24599decca06190ebca03ff9de7f8
git tree: upstream
kernel config: https://syzkaller.appspot.com/text?tag=KernelConfig&x=cd73026ceaed1402
crash reproducer: attached
======================================================
Crash log:
======================================================
UG: KASAN: use-after-free in init_inode fs/reiserfs/inode.c:1325 [inline]
BUG: KASAN: use-after-free in reiserfs_read_locked_inode+0x1f9c/0x2300
fs/reiserfs/inode.c:1574
Read of size 4 at addr ffff88819f38c000 by task syz-executor.5/13593

CPU: 0 PID: 13593 Comm: syz-executor.5 Tainted: G           OE
5.19.0-rc6-g2eae0556bb9d #2
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
1.13.0-1ubuntu1.1 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:313 [inline]
 print_report.cold+0xe5/0x659 mm/kasan/report.c:429
 kasan_report+0x8a/0x1b0 mm/kasan/report.c:491
 init_inode fs/reiserfs/inode.c:1325 [inline]
 reiserfs_read_locked_inode+0x1f9c/0x2300 fs/reiserfs/inode.c:1574
 reiserfs_fill_super+0x126c/0x2f10 fs/reiserfs/super.c:2073
 mount_bdev+0x34d/0x410 fs/super.c:1367
 legacy_get_tree+0x105/0x220 fs/fs_context.c:610
 vfs_get_tree+0x89/0x2f0 fs/super.c:1497
 do_new_mount fs/namespace.c:3040 [inline]
 path_mount+0x1228/0x1cb0 fs/namespace.c:3370
 do_mount+0xf3/0x110 fs/namespace.c:3383
 __do_sys_mount fs/namespace.c:3591 [inline]
 __se_sys_mount fs/namespace.c:3568 [inline]
 __x64_sys_mount+0x18f/0x230 fs/namespace.c:3568
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x46/0xb0
RIP: 0033:0x7f4fe2e8fe8e
Code: 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f
84 00 00 00 00 00 90 f3 0f 1e fa 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d
01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f4fe148b9f8 EFLAGS: 00000202 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0000000020000200 RCX: 00007f4fe2e8fe8e
RDX: 0000000020000040 RSI: 0000000020000100 RDI: 00007f4fe148ba50
RBP: 00007f4fe148ba90 R08: 00007f4fe148ba90 R09: 0000000020000040
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000020000040
R13: 0000000020000100 R14: 00007f4fe148ba50 R15: 0000000020011400
 </TASK>

The buggy address belongs to the physical page:
page:ffffea00067ce300 refcount:0 mapcount:-128
mapping:0000000000000000 index:0x1 pfn:0x19f38c
flags: 0x17ff00000000000(node=0|zone=2|lastcpupid=0x7ff)
raw: 017ff00000000000 ffffea000610d9c8 ffffea0006897b08 0000000000000000
raw: 0000000000000001 0000000000000000 00000000ffffff7f 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as freed
page last allocated via order 0, migratetype Movable, gfp_mask
0x140cca(GFP_HIGHUSER_MOVABLE|__GFP_COMP), pid 2972, tgid 2972
(systemd-udevd), ts 583268397100, free_ts 649857437696
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook mm/page_alloc.c:2449 [inline]
 prep_new_page+0x297/0x330 mm/page_alloc.c:2456
 get_page_from_freelist+0x2142/0x3c80 mm/page_alloc.c:4198
 __alloc_pages+0x321/0x710 mm/page_alloc.c:5426
 __folio_alloc+0x12/0x40 mm/page_alloc.c:5457
 vma_alloc_folio+0xf9/0x6e0 mm/mempolicy.c:2233
 alloc_page_vma include/linux/gfp.h:634 [inline]
 wp_page_copy+0x1f1/0x1d00 mm/memory.c:3104
 do_wp_page+0x52c/0x1840 mm/memory.c:3471
 handle_pte_fault mm/memory.c:4921 [inline]
 __handle_mm_fault+0x2a69/0x3ee0 mm/memory.c:5042
 handle_mm_fault+0x322/0xa80 mm/memory.c:5140
 do_user_addr_fault+0x489/0x11c0 arch/x86/mm/fault.c:1397
 handle_page_fault arch/x86/mm/fault.c:1484 [inline]
 exc_page_fault+0x9e/0x180 arch/x86/mm/fault.c:1540
 asm_exc_page_fault+0x27/0x30 arch/x86/include/asm/idtentry.h:570
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1371 [inline]
 free_pcp_prepare+0x51f/0xd00 mm/page_alloc.c:1421
 free_unref_page_prepare mm/page_alloc.c:3343 [inline]
 free_unref_page_list+0x15a/0xe90 mm/page_alloc.c:3475
 release_pages+0x10ea/0x2590 mm/swap.c:980
 tlb_batch_pages_flush mm/mmu_gather.c:58 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:255 [inline]
 tlb_flush_mmu+0xef/0x690 mm/mmu_gather.c:262
 tlb_finish_mmu+0x93/0x3c0 mm/mmu_gather.c:353
 exit_mmap+0x1de/0x4b0 mm/mmap.c:3164
 __mmput kernel/fork.c:1196 [inline]
 mmput+0x16b/0x430 kernel/fork.c:1217
 exit_mm kernel/exit.c:511 [inline]
 do_exit+0xa33/0x2dd0 kernel/exit.c:784
 do_group_exit+0xd2/0x2f0 kernel/exit.c:927
 __do_sys_exit_group kernel/exit.c:938 [inline]
 __se_sys_exit_group kernel/exit.c:936 [inline]
 __x64_sys_exit_group+0x3a/0x50 kernel/exit.c:936
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x46/0xb0

Memory state around the buggy address:
 ffff88819f38bf00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88819f38bf80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88819f38c000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff88819f38c080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88819f38c100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================

-- 
Thanks and Regards,

Dipanjan

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