Re: [tcp/dccp] f6408a8641: BUG:KASAN:use-after-free_in_inet_twsk_kill

From: Eric Dumazet
Date: Mon Feb 07 2022 - 00:51:26 EST

On Sun, Feb 6, 2022 at 7:03 PM kernel test robot <oliver.sang@xxxxxxxxx> wrote:
>
>
>
> Greeting,
>
> FYI, we noticed the following commit (built with gcc-9):
>
> commit: f6408a86410131190bc04d3c9b12cae45383cdd4 ("[PATCH net-next 3/6] tcp/dccp: get rid of inet_twsk_purge()")
> url: https://github.com/0day-ci/linux/commits/Eric-Dumazet/netns-speedup-netns-dismantles/20220125-061934
> base: https://git.kernel.org/cgit/linux/kernel/git/davem/net-next.git 8aaaf2f3af2ae212428f4db1af34214225f5cec3
> patch link: https://lore.kernel.org/netdev/20220124202457.3450198-4-eric.dumazet@xxxxxxxxx
>

Right, and this has been fixed in

commit fbb8295248e1d6f576d444309fcf79356008eac1
Author: Eric Dumazet <edumazet@xxxxxxxxxx>
Date: Wed Jan 26 10:07:14 2022 -0800

tcp: allocate tcp_death_row outside of struct netns_ipv4
...
Fixes: 0dad4087a86a ("tcp/dccp: get rid of inet_twsk_purge()")
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Reported-by: syzbot <syzkaller@xxxxxxxxxxxxxxxx>
Reported-by: Paolo Abeni <pabeni@xxxxxxxxxx>
Tested-by: Paolo Abeni <pabeni@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20220126180714.845362-1-eric.dumazet@xxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>



> in testcase: kernel-selftests
> version: kernel-selftests-x86_64-f050cde9-1_20220127
> with following parameters:
>
> group: net
> ucode: 0xe2
>
> test-description: The kernel contains a set of "self tests" under the tools/testing/selftests/ directory. These are intended to be small unit tests to exercise individual code paths in the kernel.
> test-url: https://www.kernel.org/doc/Documentation/kselftest.txt
>
>
> on test machine: 8 threads Intel(R) Core(TM) i7-6770HQ CPU @ 2.60GHz with 32G memory
>
> caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace):
>
>
>
> If you fix the issue, kindly add following tag
> Reported-by: kernel test robot <oliver.sang@xxxxxxxxx>
>
>
> [ 1799.534962][ C0] BUG: KASAN: use-after-free in inet_twsk_kill (net/ipv4/inet_timewait_sock.c:46)
> [ 1799.542232][ C0] Read of size 8 at addr ffff88889835ea80 by task swapper/0/0
> [ 1799.549806][ C0]
> [ 1799.552099][ C0] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G I 5.16.0-rc8-02293-gf6408a864101 #1
> [ 1799.562554][ C0] Hardware name: /NUC6i7KYB, BIOS KYSKLi70.86A.0041.2016.0817.1130 08/17/2016
> [ 1799.571654][ C0] Call Trace:
> [ 1799.574923][ C0] <IRQ>
> [ 1799.577747][ C0] dump_stack_lvl (lib/dump_stack.c:107)
> [ 1799.582294][ C0] print_address_description+0x21/0x140
> [ 1799.588939][ C0] ? inet_twsk_kill (net/ipv4/inet_timewait_sock.c:46)
> [ 1799.593855][ C0] ? inet_twsk_kill (net/ipv4/inet_timewait_sock.c:46)
> [ 1799.598850][ C0] kasan_report.cold (mm/kasan/report.c:434 mm/kasan/report.c:450)
> [ 1799.603906][ C0] ? inet_twsk_kill (net/ipv4/inet_timewait_sock.c:46)
> [ 1799.608942][ C0] ? inet_twsk_kill (net/ipv4/inet_timewait_sock.c:148)
> [ 1799.614060][ C0] inet_twsk_kill (net/ipv4/inet_timewait_sock.c:46)
> [ 1799.619048][ C0] ? inet_twsk_kill (net/ipv4/inet_timewait_sock.c:148)
> [ 1799.624088][ C0] call_timer_fn (arch/x86/include/asm/jump_label.h:27 include/linux/jump_label.h:212 include/trace/events/timer.h:125 kernel/time/timer.c:1422)
> [ 1799.628802][ C0] ? lock_release (kernel/locking/lockdep.c:5315 kernel/locking/lockdep.c:5657)
> [ 1799.633639][ C0] ? del_timer_sync (kernel/time/timer.c:1398)
> [ 1799.638650][ C0] ? lock_downgrade (kernel/locking/lockdep.c:5645)
> [ 1799.643768][ C0] ? inet_twsk_kill (net/ipv4/inet_timewait_sock.c:148)
> [ 1799.648731][ C0] ? lockdep_hardirqs_on_prepare (kernel/locking/lockdep.c:4224 kernel/locking/lockdep.c:4292 kernel/locking/lockdep.c:4244)
> [ 1799.654797][ C0] ? inet_twsk_kill (net/ipv4/inet_timewait_sock.c:148)
> [ 1799.659608][ C0] run_timer_softirq (kernel/time/timer.c:1467 kernel/time/timer.c:1734 kernel/time/timer.c:1710 kernel/time/timer.c:1747)
> [ 1799.664743][ C0] ? call_timer_fn (kernel/time/timer.c:1744)
> [ 1799.669655][ C0] ? __next_base (kernel/time/hrtimer.c:506)
> [ 1799.674329][ C0] ? rcu_read_lock_sched_held (include/linux/lockdep.h:283 kernel/rcu/update.c:125)
> [ 1799.679957][ C0] ? rcu_read_lock_bh_held (kernel/rcu/update.c:120)
> [ 1799.685223][ C0] __do_softirq (arch/x86/include/asm/jump_label.h:27 include/linux/jump_label.h:212 include/trace/events/irq.h:142 kernel/softirq.c:559)
> [ 1799.689695][ C0] irq_exit_rcu (kernel/softirq.c:432 kernel/softirq.c:637 kernel/softirq.c:649)
> [ 1799.694165][ C0] sysvec_apic_timer_interrupt (arch/x86/kernel/apic/apic.c:1097 (discriminator 14))
> [ 1799.699785][ C0] </IRQ>
> [ 1799.702672][ C0] <TASK>
> [ 1799.705613][ C0] asm_sysvec_apic_timer_interrupt (arch/x86/include/asm/idtentry.h:638)
> [ 1799.711800][ C0] RIP: 0010:cpuidle_enter_state (drivers/cpuidle/cpuidle.c:259)
> [ 1799.717839][ C0] Code: 00 00 31 ff e8 47 58 43 fe 80 3c 24 00 74 12 9c 58 f6 c4 02 0f 85 1f 08 00 00 31 ff e8 6f 9c 5b fe e8 aa 0f 71 fe fb 45 85 f6 <0f> 88 90 03 00 00 49 63 ee 48 83 fd 09 0f 87 62 09 00 00 48 8d 44
> All code
> ========
> 0: 00 00 add %al,(%rax)
> 2: 31 ff xor %edi,%edi
> 4: e8 47 58 43 fe callq 0xfffffffffe435850
> 9: 80 3c 24 00 cmpb $0x0,(%rsp)
> d: 74 12 je 0x21
> f: 9c pushfq
> 10: 58 pop %rax
> 11: f6 c4 02 test $0x2,%ah
> 14: 0f 85 1f 08 00 00 jne 0x839
> 1a: 31 ff xor %edi,%edi
> 1c: e8 6f 9c 5b fe callq 0xfffffffffe5b9c90
> 21: e8 aa 0f 71 fe callq 0xfffffffffe710fd0
> 26: fb sti
> 27: 45 85 f6 test %r14d,%r14d
> 2a:* 0f 88 90 03 00 00 js 0x3c0 <-- trapping instruction
> 30: 49 63 ee movslq %r14d,%rbp
> 33: 48 83 fd 09 cmp $0x9,%rbp
> 37: 0f 87 62 09 00 00 ja 0x99f
> 3d: 48 rex.W
> 3e: 8d .byte 0x8d
> 3f: 44 rex.R
>
> Code starting with the faulting instruction
> ===========================================
> 0: 0f 88 90 03 00 00 js 0x396
> 6: 49 63 ee movslq %r14d,%rbp
> 9: 48 83 fd 09 cmp $0x9,%rbp
> d: 0f 87 62 09 00 00 ja 0x975
> 13: 48 rex.W
> 14: 8d .byte 0x8d
> 15: 44 rex.R
> [ 1799.738502][ C0] RSP: 0018:ffffffff85007dd8 EFLAGS: 00000202
> [ 1799.744586][ C0] RAX: 00000000012d2f7d RBX: ffffe8ffffa02090 RCX: 1ffffffff0bfa611
> [ 1799.752936][ C0] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff83055f16
> [ 1799.761247][ C0] RBP: 0000000000000004 R08: 0000000000000001 R09: 0000000000000001
> [ 1799.769680][ C0] R10: ffffffff85fd86e7 R11: fffffbfff0bfb0dc R12: ffffffff85a79e80
> [ 1799.778069][ C0] R13: 000001a2fc2052e6 R14: 0000000000000004 R15: 0000000000000000
> [ 1799.782354][ T6832] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready
> [ 1799.786409][ C0] ? cpuidle_enter_state (arch/x86/include/asm/irqflags.h:45 arch/x86/include/asm/irqflags.h:80 drivers/cpuidle/cpuidle.c:257)
> [ 1799.799117][ C0] ? cpuidle_enter_state (arch/x86/include/asm/irqflags.h:45 arch/x86/include/asm/irqflags.h:80 drivers/cpuidle/cpuidle.c:257)
> [ 1799.804473][ C0] ? menu_reflect (drivers/cpuidle/governors/menu.c:267)
> [ 1799.809304][ C0] cpuidle_enter (drivers/cpuidle/cpuidle.c:353)
> [ 1799.813795][ C0] do_idle (kernel/sched/idle.c:158 kernel/sched/idle.c:239 kernel/sched/idle.c:306)
> [ 1799.817917][ C0] ? arch_cpu_idle_exit+0xc0/0xc0
> [ 1799.823009][ C0] cpu_startup_entry (kernel/sched/idle.c:402 (discriminator 1))
> [ 1799.827914][ C0] start_kernel (init/main.c:1137)
> [ 1799.832479][ C0] secondary_startup_64_no_verify (arch/x86/kernel/head_64.S:283)
> [ 1799.838530][ C0] </TASK>
> [ 1799.841584][ C0]
> [ 1799.843870][ C0] Allocated by task 19319:
> [ 1799.848379][ C0] kasan_save_stack (mm/kasan/common.c:38)
> [ 1799.853303][ C0] __kasan_slab_alloc (mm/kasan/common.c:46 mm/kasan/common.c:434 mm/kasan/common.c:467)
> [ 1799.858176][ C0] kmem_cache_alloc (mm/slab.h:520 mm/slub.c:3234 mm/slub.c:3242 mm/slub.c:3247)
> [ 1799.863091][ C0] copy_net_ns (include/linux/slab.h:714 net/core/net_namespace.c:404 net/core/net_namespace.c:459)
> [ 1799.867457][ C0] create_new_namespaces+0x335/0x900
> [ 1799.873494][ C0] unshare_nsproxy_namespaces (kernel/nsproxy.c:226 (discriminator 4))
> [ 1799.879267][ C0] ksys_unshare (kernel/fork.c:3075)
> [ 1799.883868][ C0] __x64_sys_unshare (kernel/fork.c:3144)
> [ 1799.888661][ C0] do_syscall_64 (arch/x86/entry/common.c:50 arch/x86/entry/common.c:80)
> [ 1799.893312][ C0] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:113)
> [ 1799.899477][ C0]
> [ 1799.901845][ C0] The buggy address belongs to the object at ffff88889835e600
> [ 1799.901845][ C0] which belongs to the cache net_namespace of size 6272
> [ 1799.916823][ C0] The buggy address is located 1152 bytes inside of
> [ 1799.916823][ C0] 6272-byte region [ffff88889835e600, ffff88889835fe80)
> [ 1799.930935][ C0] The buggy address belongs to the page:
> [ 1799.936797][ C0] page:0000000041ff24a7 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88889835e600 pfn:0x898358
> [ 1799.948909][ C0] head:0000000041ff24a7 order:3 compound_mapcount:0 compound_pincount:0
> [ 1799.957574][ C0] memcg:ffff8881e9591681
> [ 1799.961926][ C0] flags: 0x17ffffc0010200(slab|head|node=0|zone=2|lastcpupid=0x1fffff)
> [ 1799.970490][ C0] raw: 0017ffffc0010200 ffffea000a32ac00 dead000000000002 ffff888100bc8c80
> [ 1799.979427][ C0] raw: ffff88889835e600 0000000080050004 00000001ffffffff ffff8881e9591681
> [ 1799.988352][ C0] page dumped because: kasan: bad access detected
> [ 1799.995035][ C0]
> [ 1799.997380][ C0] Memory state around the buggy address:
> [ 1800.003163][ C0] ffff88889835e980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> [ 1800.011374][ C0] ffff88889835ea00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> [ 1800.019699][ C0] >ffff88889835ea80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> [ 1800.028007][ C0] ^
> [ 1800.032207][ C0] ffff88889835eb00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> [ 1800.040602][ C0] ffff88889835eb80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> [ 1800.049061][ C0] ==================================================================
> [ 1800.057470][ C0] Disabling lock debugging due to kernel taint
> [ 1800.364663][ T434] # tx=19158 (1195 MB) txc=0 zc=n
> [ 1800.364686][ T434]
> [ 1800.763181][ T434] # rx=9578 (1195 MB)
> [ 1800.763193][ T434]
> [ 1800.769974][ T434] # ipv6 tcp -z -t 1
> [ 1800.769984][ T434]
> [ 1802.219504][ T434] # tx=17552 (1095 MB) txc=17552 zc=n
> [ 1802.219515][ T434]
> [ 1802.577158][ T434] # rx=8777 (1095 MB)
> [ 1802.577170][ T434]
> [ 1802.583655][ T434] # ok
> [ 1802.583669][ T434]
> [ 1802.697567][T19410] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready
> [ 1802.754498][ T434] # ipv4 udp -t 1
> [ 1802.754512][ T434]
> [ 1803.686331][T19410] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready
> [ 1804.167573][ T434] # tx=40439 (2523 MB) txc=0 zc=n
> [ 1804.167595][ T434]
> [ 1804.666768][ T434] # rx=40439 (2523 MB)
> [ 1804.666780][ T434]
> [ 1804.673747][ T434] # ipv4 udp -z -t 1
> [ 1804.673755][ T434]
> [ 1806.082032][ T434] # tx=18970 (1183 MB) txc=18970 zc=n
> [ 1806.082049][ T434]
> [ 1806.580275][ T434] # rx=18956 (1182 MB)
> [ 1806.580321][ T434]
> [ 1806.587038][ T434] # ok
> [ 1806.587045][ T434]
> [ 1806.717784][ T100] IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready
> [ 1806.781443][ T434] # ipv6 udp -t 1
>
>
> To reproduce:
>
> git clone https://github.com/intel/lkp-tests.git
> cd lkp-tests
> sudo bin/lkp install job.yaml # job file is attached in this email
> bin/lkp split-job --compatible job.yaml # generate the yaml file for lkp run
> sudo bin/lkp run generated-yaml-file
>
> # if come across any failure that blocks the test,
> # please remove ~/.lkp and /lkp dir to run from a clean state.
>
>
>
> ---
> 0DAY/LKP+ Test Infrastructure Open Source Technology Center
> https://lists.01.org/hyperkitty/list/lkp@xxxxxxxxxxxx Intel Corporation
>
> Thanks,
> Oliver Sang
>