KASAN: use-after-free Read in tcp_write_timer_handler

From: Hao Sun
Date: Tue Sep 21 2021 - 21:45:18 EST

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Hello,

When using Healer to fuzz the latest Linux kernel, the following crash
was triggered.

HEAD commit: 4357f03d6611 Merge tag 'pm-5.15-rc2
git tree: upstream
console output:
https://drive.google.com/file/d/1TvIf-dvfzbm8RKtYz9QHfPWixHnjIcFW/view?usp=sharing
kernel config: https://drive.google.com/file/d/1HKZtF_s3l6PL3OoQbNq_ei9CdBus-Tz0/view?usp=sharing
Similar report:
https://syzkaller.appspot.com/bug?id=83d75b561d8b1b2529c635338ecfb7136261db11

Sorry, I don't have a reproducer for this crash, hope the symbolized
report can help.
If you fix this issue, please add the following tag to the commit:
Reported-by: Hao Sun <sunhao.th@xxxxxxxxx>

==================================================================
BUG: KASAN: use-after-free in tcp_probe_timer net/ipv4/tcp_timer.c:383 [inline]
BUG: KASAN: use-after-free in tcp_write_timer_handler+0x8fd/0x940
net/ipv4/tcp_timer.c:626
Read of size 1 at addr ffff88802272a0d5 by task syz-executor/12060

CPU: 2 PID: 12060 Comm: syz-executor Not tainted 5.15.0-rc1+ #10
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
1.13.0-1ubuntu1.1 04/01/2014
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
print_address_description.constprop.0.cold+0x93/0x334 mm/kasan/report.c:256
__kasan_report mm/kasan/report.c:442 [inline]
kasan_report.cold+0x83/0xdf mm/kasan/report.c:459
tcp_probe_timer net/ipv4/tcp_timer.c:383 [inline]
tcp_write_timer_handler+0x8fd/0x940 net/ipv4/tcp_timer.c:626
tcp_write_timer+0xa2/0x2b0 net/ipv4/tcp_timer.c:642
call_timer_fn+0x1a5/0x6b0 kernel/time/timer.c:1421
expire_timers kernel/time/timer.c:1466 [inline]
__run_timers.part.0+0x6b0/0xa90 kernel/time/timer.c:1734
__run_timers kernel/time/timer.c:1715 [inline]
run_timer_softirq+0xb6/0x1d0 kernel/time/timer.c:1747
__do_softirq+0x1d7/0x93b kernel/softirq.c:558
invoke_softirq kernel/softirq.c:432 [inline]
__irq_exit_rcu kernel/softirq.c:636 [inline]
irq_exit_rcu+0xf2/0x130 kernel/softirq.c:648
sysvec_apic_timer_interrupt+0x93/0xc0 arch/x86/kernel/apic/apic.c:1097
</IRQ>
asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638
RIP: 0010:zap_pte_range mm/memory.c:1335 [inline]
RIP: 0010:zap_pmd_range mm/memory.c:1481 [inline]
RIP: 0010:zap_pud_range mm/memory.c:1510 [inline]
RIP: 0010:zap_p4d_range mm/memory.c:1531 [inline]
RIP: 0010:unmap_page_range+0xbdd/0x2da0 mm/memory.c:1552
Code: 00 00 00 48 89 44 24 08 e9 8a f5 ff ff e8 4b 97 ca ff 48 8b 74
24 08 4c 89 ea 48 8b 7c 24 48 e8 69 ec ff ff 48 83 7c 24 38 00 <49> 89
c7 0f 85 02 15 00 00 e8 25 97 ca ff 48 8b 44 24 10 48 8d 68
RSP: 0018:ffffc900092cf7a0 EFLAGS: 00000246
RAX: ffffea000080c780 RBX: 0000000000000025 RCX: ffff888104079c80
RDX: 0000000000000000 RSI: ffff888104079c80 RDI: 0000000000000002
RBP: 0000000000000001 R08: ffffffff81aba2c6 R09: 000000000013ffff
R10: 0000000000000006 R11: ffffed102080f390 R12: 0000000000000025
R13: 000000002031e025 R14: dffffc0000000000 R15: 00000000004db000
unmap_single_vma+0x198/0x310 mm/memory.c:1597
unmap_vmas+0x16d/0x2f0 mm/memory.c:1629
exit_mmap+0x1d0/0x650 mm/mmap.c:3171
__mmput kernel/fork.c:1115 [inline]
mmput+0x16d/0x440 kernel/fork.c:1136
exit_mm kernel/exit.c:501 [inline]
do_exit+0xad6/0x2dd0 kernel/exit.c:812
do_group_exit+0x125/0x340 kernel/exit.c:922
get_signal+0x4d5/0x25a0 kernel/signal.c:2868
arch_do_signal_or_restart+0x2ed/0x1c40 arch/x86/kernel/signal.c:865
handle_signal_work kernel/entry/common.c:148 [inline]
exit_to_user_mode_loop kernel/entry/common.c:172 [inline]
exit_to_user_mode_prepare+0x192/0x2a0 kernel/entry/common.c:209
__syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:302
do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x4739cd
Code: Unable to access opcode bytes at RIP 0x4739a3.
RSP: 002b:00007f4ef3c1bcd8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 000000000059c0a0 RCX: 00000000004739cd
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000059c0a8
RBP: 000000000059c0a8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000059c0ac
R13: 00007ffc59e0995f R14: 00007ffc59e09b00 R15: 00007f4ef3c1bdc0

Allocated by task 10273:
kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
kasan_set_track mm/kasan/common.c:46 [inline]
set_alloc_info mm/kasan/common.c:434 [inline]
__kasan_slab_alloc+0x83/0xb0 mm/kasan/common.c:467
kasan_slab_alloc include/linux/kasan.h:254 [inline]
slab_post_alloc_hook+0x4d/0x4b0 mm/slab.h:519
slab_alloc_node mm/slub.c:3206 [inline]
slab_alloc mm/slub.c:3214 [inline]
kmem_cache_alloc+0x150/0x340 mm/slub.c:3219
kmem_cache_zalloc include/linux/slab.h:711 [inline]
net_alloc net/core/net_namespace.c:402 [inline]
copy_net_ns+0xea/0x660 net/core/net_namespace.c:457
create_new_namespaces.isra.0+0x3cb/0xae0 kernel/nsproxy.c:110
unshare_nsproxy_namespaces+0xc8/0x1f0 kernel/nsproxy.c:226
ksys_unshare+0x445/0x920 kernel/fork.c:3077
__do_sys_unshare kernel/fork.c:3151 [inline]
__se_sys_unshare kernel/fork.c:3149 [inline]
__x64_sys_unshare+0x2d/0x40 kernel/fork.c:3149
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+0x44/0xae

The buggy address belongs to the object at ffff888022729a40
which belongs to the cache net_namespace of size 6464
The buggy address is located 1685 bytes inside of
6464-byte region [ffff888022729a40, ffff88802272b380)
The buggy address belongs to the page:
page:ffffea000089ca00 refcount:1 mapcount:0 mapping:0000000000000000
index:0xffff888022729a40 pfn:0x22728
head:ffffea000089ca00 order:3 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 0000000000000000 dead000000000122 ffff888010e0c500
raw: ffff888022729a40 0000000080040002 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask
0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC),
pid 9342, ts 177339275214, free_ts 174923780601
set_page_owner include/linux/page_owner.h:31 [inline]
post_alloc_hook mm/page_alloc.c:2418 [inline]
prep_new_page+0x1a5/0x240 mm/page_alloc.c:2424
get_page_from_freelist+0x1f10/0x3b70 mm/page_alloc.c:4153
__alloc_pages+0x306/0x6e0 mm/page_alloc.c:5375
alloc_pages+0x115/0x240 mm/mempolicy.c:2197
alloc_slab_page mm/slub.c:1763 [inline]
allocate_slab mm/slub.c:1900 [inline]
new_slab+0x34a/0x480 mm/slub.c:1963
___slab_alloc+0xa9f/0x10d0 mm/slub.c:2994
__slab_alloc.isra.0+0x4d/0xa0 mm/slub.c:3081
slab_alloc_node mm/slub.c:3172 [inline]
slab_alloc mm/slub.c:3214 [inline]
kmem_cache_alloc+0x31e/0x340 mm/slub.c:3219
kmem_cache_zalloc include/linux/slab.h:711 [inline]
net_alloc net/core/net_namespace.c:402 [inline]
copy_net_ns+0xea/0x660 net/core/net_namespace.c:457
create_new_namespaces.isra.0+0x3cb/0xae0 kernel/nsproxy.c:110
copy_namespaces+0x391/0x450 kernel/nsproxy.c:178
copy_process+0x2d37/0x73d0 kernel/fork.c:2197
kernel_clone+0xe7/0x10d0 kernel/fork.c:2584
__do_sys_clone+0xc8/0x110 kernel/fork.c:2701
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+0x44/0xae
page last free stack trace:
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1338 [inline]
free_pcp_prepare+0x412/0x900 mm/page_alloc.c:1389
free_unref_page_prepare mm/page_alloc.c:3315 [inline]
free_unref_page+0x19/0x580 mm/page_alloc.c:3394
__unfreeze_partials+0x340/0x360 mm/slub.c:2495
qlink_free mm/kasan/quarantine.c:146 [inline]
qlist_free_all+0x5a/0xc0 mm/kasan/quarantine.c:165
kasan_quarantine_reduce+0x13d/0x180 mm/kasan/quarantine.c:272
__kasan_slab_alloc+0x95/0xb0 mm/kasan/common.c:444
kasan_slab_alloc include/linux/kasan.h:254 [inline]
slab_post_alloc_hook+0x4d/0x4b0 mm/slab.h:519
slab_alloc_node mm/slub.c:3206 [inline]
slab_alloc mm/slub.c:3214 [inline]
kmem_cache_alloc+0x150/0x340 mm/slub.c:3219
kmem_cache_zalloc include/linux/slab.h:711 [inline]
jbd2_alloc_handle include/linux/jbd2.h:1603 [inline]
new_handle fs/jbd2/transaction.c:481 [inline]
jbd2__journal_start fs/jbd2/transaction.c:508 [inline]
jbd2__journal_start+0x191/0x920 fs/jbd2/transaction.c:490
__ext4_journal_start_sb+0x3a8/0x4a0 fs/ext4/ext4_jbd2.c:105
__ext4_journal_start fs/ext4/ext4_jbd2.h:326 [inline]
ext4_da_write_begin+0x4c5/0x1180 fs/ext4/inode.c:3002
generic_perform_write+0x1fe/0x510 mm/filemap.c:3770
ext4_buffered_write_iter+0x206/0x4c0 fs/ext4/file.c:269
ext4_file_write_iter+0x42e/0x14a0 fs/ext4/file.c:680
call_write_iter include/linux/fs.h:2163 [inline]
do_iter_readv_writev+0x47b/0x750 fs/read_write.c:729
do_iter_write fs/read_write.c:855 [inline]
do_iter_write+0x18b/0x700 fs/read_write.c:836

Memory state around the buggy address:
ffff888022729f80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88802272a000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88802272a080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88802272a100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88802272a180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
----------------
Code disassembly (best guess):
0: 00 00 add %al,(%rax)
2: 00 48 89 add %cl,-0x77(%rax)
5: 44 24 08 rex.R and $0x8,%al
8: e9 8a f5 ff ff jmpq 0xfffff597
d: e8 4b 97 ca ff callq 0xffca975d
12: 48 8b 74 24 08 mov 0x8(%rsp),%rsi
17: 4c 89 ea mov %r13,%rdx
1a: 48 8b 7c 24 48 mov 0x48(%rsp),%rdi
1f: e8 69 ec ff ff callq 0xffffec8d
24: 48 83 7c 24 38 00 cmpq $0x0,0x38(%rsp)
* 2a: 49 89 c7 mov %rax,%r15 <-- trapping instruction
2d: 0f 85 02 15 00 00 jne 0x1535
33: e8 25 97 ca ff callq 0xffca975d
38: 48 8b 44 24 10 mov 0x10(%rsp),%rax
3d: 48 rex.W
3e: 8d .byte 0x8d
3f: 68 .byte 0x68

Next message: Chen Jun: "[PATCH v2 1/1] mm: Fix the uninitialized use in overcommit_policy_handler"
Previous message: Shengjiu Wang: "Re: [PATCH v4 3/4] remoteproc: imx_dsp_rproc: Add remoteproc driver for DSP on i.MX"
Next in thread: Eric Dumazet: "Re: KASAN: use-after-free Read in tcp_write_timer_handler"
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