[Android 5.10] KASAN: use-after-free Read in __ext4_check_dir_entry

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 70b6ab09a34b Revert "hrtimer: Report offline hrtimer enque..
git tree: android13-5.10-lts
console+strace: https://syzkaller.appspot.com/x/log.txt?x=1196303f180000
kernel config: https://syzkaller.appspot.com/x/.config?x=32ace1916c4b73d8
dashboard link: https://syzkaller.appspot.com/bug?extid=8f42da1dbf662eb1d6f0
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16cc5b70980000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=162be85c980000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/c2e16761410a/disk-70b6ab09.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/d0874dd2861d/vmlinux-70b6ab09.xz
kernel image: https://storage.googleapis.com/syzbot-assets/4e2f94cb7466/bzImage-70b6ab09.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/5401de323a8a/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+8f42da...@syzkaller.appspotmail.com

EXT4-fs error (device loop0): make_indexed_dir:2245: inode #2: block 255: comm syz-executor320: bad entry in directory: rec_len is smaller than minimal - offset=1024, inode=5120, rec_len=0, size=993 fake=0
EXT4-fs warning (device loop0): dx_probe:805: inode #2: comm syz-executor320: Unrecognised inode hash code 49
EXT4-fs warning (device loop0): dx_probe:945: inode #2: comm syz-executor320: Corrupt directory, running e2fsck is recommended
==================================================================
BUG: KASAN: use-after-free in __ext4_check_dir_entry+0x700/0x880 fs/ext4/dir.c:85
Read of size 2 at addr ffff888116f28003 by task syz-executor320/321

CPU: 0 PID: 321 Comm: syz-executor320 Not tainted 5.10.210-syzkaller-00394-g70b6ab09a34b #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack_lvl+0x1e2/0x24b lib/dump_stack.c:118
print_address_description+0x81/0x3b0 mm/kasan/report.c:248
__kasan_report mm/kasan/report.c:435 [inline]
kasan_report+0x179/0x1c0 mm/kasan/report.c:452
__asan_report_load2_noabort+0x14/0x20 mm/kasan/report_generic.c:307
__ext4_check_dir_entry+0x700/0x880 fs/ext4/dir.c:85
ext4_readdir+0x1402/0x37c0 fs/ext4/dir.c:258
iterate_dir+0x265/0x580
__do_sys_getdents64 fs/readdir.c:369 [inline]
__se_sys_getdents64+0x1c1/0x460 fs/readdir.c:354
__x64_sys_getdents64+0x7b/0x90 fs/readdir.c:354
do_syscall_64+0x34/0x70
entry_SYSCALL_64_after_hwframe+0x61/0xc6
RIP: 0033:0x7fe88ee8e0e9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 21 18 00 00 90 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffc23661ba8 EFLAGS: 00000246 ORIG_RAX: 00000000000000d9
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007fe88ee8e0e9
RDX: 0000000000000010 RSI: 0000000000000000 RDI: 0000000000000005
RBP: 0000000000000000 R08: 00007ffc23661bdc R09: 00007ffc23661bdc
R10: 00007ffc23661bdc R11: 0000000000000246 R12: 00007ffc23661bdc
R13: 000000000000000a R14: 431bde82d7b634db R15: 00007ffc23661c10

The buggy address belongs to the page:
page:ffffea00045bca00 refcount:0 mapcount:-128 mapping:0000000000000000 index:0x1 pfn:0x116f28
flags: 0x4000000000000000()
raw: 4000000000000000 ffffea00045bd6c8 ffffea0004431488 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 0x8100dca(GFP_HIGHUSER_MOVABLE|__GFP_ZERO|0x8000000), pid 230, ts 14510620823, free_ts 14512075758
set_page_owner include/linux/page_owner.h:35 [inline]
post_alloc_hook mm/page_alloc.c:2456 [inline]
prep_new_page+0x166/0x180 mm/page_alloc.c:2462
get_page_from_freelist+0x2d8c/0x2f30 mm/page_alloc.c:4254
__alloc_pages_nodemask+0x435/0xaf0 mm/page_alloc.c:5346
__alloc_pages include/linux/gfp.h:544 [inline]
__alloc_pages_node include/linux/gfp.h:557 [inline]
alloc_pages_node include/linux/gfp.h:571 [inline]
alloc_pages include/linux/gfp.h:590 [inline]
do_anonymous_page mm/memory.c:3934 [inline]
handle_pte_fault+0x174f/0x3de0 mm/memory.c:4757
__handle_mm_fault mm/memory.c:4915 [inline]
handle_mm_fault+0x11d6/0x1a10 mm/memory.c:5329
do_user_addr_fault arch/x86/mm/fault.c:1396 [inline]
handle_page_fault arch/x86/mm/fault.c:1462 [inline]
exc_page_fault+0x2a6/0x5b0 arch/x86/mm/fault.c:1518
asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:571
page last free stack trace:
reset_page_owner include/linux/page_owner.h:28 [inline]
free_pages_prepare mm/page_alloc.c:1349 [inline]
free_pcp_prepare mm/page_alloc.c:1421 [inline]
free_unref_page_prepare+0x2ae/0x2d0 mm/page_alloc.c:3336
free_unref_page_list+0x122/0xb20 mm/page_alloc.c:3443
release_pages+0xea0/0xef0 mm/swap.c:1103
free_pages_and_swap_cache+0x8a/0xa0 mm/swap_state.c:356
tlb_batch_pages_flush mm/mmu_gather.c:49 [inline]
tlb_flush_mmu_free mm/mmu_gather.c:240 [inline]
tlb_flush_mmu mm/mmu_gather.c:247 [inline]
tlb_finish_mmu+0x177/0x320 mm/mmu_gather.c:326
unmap_region+0x31c/0x370 mm/mmap.c:2807
__do_munmap+0x699/0x8c0 mm/mmap.c:3036
__vm_munmap mm/mmap.c:3059 [inline]
__do_sys_munmap mm/mmap.c:3085 [inline]
__se_sys_munmap+0x120/0x1a0 mm/mmap.c:3081
__x64_sys_munmap+0x5b/0x70 mm/mmap.c:3081
do_syscall_64+0x34/0x70
entry_SYSCALL_64_after_hwframe+0x61/0xc6

Memory state around the buggy address:
ffff888116f27f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff888116f27f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888116f28000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
^
ffff888116f28080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff888116f28100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
EXT4-fs error (device loop0): ext4_readdir:260: inode #2: block 255: comm syz-executor320: path /root/syzkaller.u2Naqf/10/file0: bad entry in directory: rec_len is smaller than minimal - offset=1023, inode=0, rec_len=0, size=1024 fake=0


---
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[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 4d55129aea65 UPSTREAM: crypto: x86/curve25519 - disable gcov
git tree: android14-6.1
console+strace: https://syzkaller.appspot.com/x/log.txt?x=106710cc980000
kernel config: https://syzkaller.appspot.com/x/.config?x=4a340f281ebc7608
dashboard link: https://syzkaller.appspot.com/bug?extid=3f08b9d4d6ca05d557f8

compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13b59bbc980000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10be7d04980000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/a8e23b3a85b8/disk-4d55129a.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/c7d768734df0/vmlinux-4d55129a.xz
kernel image: https://storage.googleapis.com/syzbot-assets/2c636465af27/bzImage-4d55129a.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/a6ce4ae5c18f/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:

Reported-by: syzbot+3f08b9...@syzkaller.appspotmail.com

EXT4-fs warning (device loop0): dx_probe:832: inode #2: comm syz-executor231: Unrecognised inode hash code 49
EXT4-fs warning (device loop0): dx_probe:965: inode #2: comm syz-executor231: Corrupt directory, running e2fsck is recommended

==================================================================
BUG: KASAN: use-after-free in __ext4_check_dir_entry+0x700/0x880 fs/ext4/dir.c:85

Read of size 2 at addr ffff8881217cb003 by task syz-executor231/300

CPU: 1 PID: 300 Comm: syz-executor231 Not tainted 6.1.75-syzkaller-00003-g4d55129aea65 #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Call Trace:

<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x151/0x1b7 lib/dump_stack.c:106
print_address_description mm/kasan/report.c:316 [inline]
print_report+0x158/0x4e0 mm/kasan/report.c:427
kasan_report+0x13c/0x170 mm/kasan/report.c:531
__asan_report_load2_noabort+0x14/0x20 mm/kasan/report_generic.c:349
__ext4_check_dir_entry+0x700/0x880 fs/ext4/dir.c:85
ext4_readdir+0x1386/0x3930 fs/ext4/dir.c:258
iterate_dir+0x265/0x610

__do_sys_getdents64 fs/readdir.c:369 [inline]
__se_sys_getdents64+0x1c1/0x460 fs/readdir.c:354
__x64_sys_getdents64+0x7b/0x90 fs/readdir.c:354

do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f3f8b08c0e9

Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 21 18 00 00 90 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 b8 ff ff ff f7 d8 64 89 01 48

RSP: 002b:00007ffc4c3447a8 EFLAGS: 00000246 ORIG_RAX: 00000000000000d9
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f3f8b08c0e9

RDX: 0000000000000010 RSI: 0000000000000000 RDI: 0000000000000005

RBP: 0000000000000000 R08: 00007ffc4c3447dc R09: 00007ffc4c3447dc
R10: 00007ffc4c3447dc R11: 0000000000000246 R12: 00007ffc4c3447dc
R13: 0000000000000001 R14: 431bde82d7b634db R15: 00007ffc4c344810
</TASK>

The buggy address belongs to the physical page:
page:ffffea000485f2c0 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x1217cb
flags: 0x4000000000000000(zone=1)
raw: 4000000000000000 ffffea000485f308 ffff8881f703bb68 0000000000000000
raw: 0000000000000001 0000000000000000 00000000ffffffff 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 0x8140dca(GFP_HIGHUSER_MOVABLE|__GFP_COMP|__GFP_ZERO|__GFP_CMA), pid 235, tgid 235 (sshd), ts 14746125651, free_ts 14770395574
set_page_owner include/linux/page_owner.h:33 [inline]
post_alloc_hook+0x213/0x220 mm/page_alloc.c:2590
prep_new_page+0x1b/0x110 mm/page_alloc.c:2597
get_page_from_freelist+0x27ea/0x2870 mm/page_alloc.c:4425
__alloc_pages+0x3a1/0x780 mm/page_alloc.c:5712
__folio_alloc+0x15/0x40 mm/page_alloc.c:5744
__folio_alloc_node include/linux/gfp.h:245 [inline]
folio_alloc include/linux/gfp.h:274 [inline]
alloc_page_vma include/linux/gfp.h:283 [inline]
do_anonymous_page mm/memory.c:4219 [inline]
handle_pte_fault mm/memory.c:5094 [inline]
__handle_mm_fault mm/memory.c:5238 [inline]
handle_mm_fault+0x1fb0/0x2f40 mm/memory.c:5378
do_user_addr_fault arch/x86/mm/fault.c:1363 [inline]
handle_page_fault arch/x86/mm/fault.c:1506 [inline]
exc_page_fault+0x3b3/0x700 arch/x86/mm/fault.c:1562
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:26 [inline]
free_pages_prepare mm/page_alloc.c:1498 [inline]
free_pcp_prepare mm/page_alloc.c:1572 [inline]
free_unref_page_prepare+0x83d/0x850 mm/page_alloc.c:3498
free_unref_page_list+0xf1/0x7b0 mm/page_alloc.c:3646
release_pages+0xf7f/0xfe0 mm/swap.c:1063
free_pages_and_swap_cache+0x8a/0xa0 mm/swap_state.c:314
tlb_batch_pages_flush mm/mmu_gather.c:59 [inline]
tlb_flush_mmu_free mm/mmu_gather.c:254 [inline]
tlb_flush_mmu mm/mmu_gather.c:261 [inline]
tlb_finish_mmu+0x1e0/0x3f0 mm/mmu_gather.c:361
unmap_region+0x2c1/0x310 mm/mmap.c:2405
do_mas_align_munmap+0xd05/0x1400 mm/mmap.c:2672
do_mas_munmap+0x23e/0x2b0 mm/mmap.c:2730
__vm_munmap+0x263/0x3a0 mm/mmap.c:3020
__do_sys_munmap mm/mmap.c:3046 [inline]
__se_sys_munmap mm/mmap.c:3042 [inline]
__x64_sys_munmap+0x6b/0x80 mm/mmap.c:3042
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x63/0xcd

Memory state around the buggy address:

ffff8881217caf00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff8881217caf80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8881217cb000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
^
ffff8881217cb080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
ffff8881217cb100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
EXT4-fs error (device loop0): ext4_readdir:260: inode #2: block 255: comm syz-executor231: path /root/syzkaller.uT7fTt/1/file0: bad entry in directory: directory entry overrun - offset=1023, inode=542842880, rec_len=8224, size=1024 fake=0