linux/kernel
Pu Lehui 222bd95c89 bpf, cgroup: Fix kernel BUG in purge_effective_progs
[ Upstream commit 7d6620f107 ]

Syzkaller reported a triggered kernel BUG as follows:

  ------------[ cut here ]------------
  kernel BUG at kernel/bpf/cgroup.c:925!
  invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
  CPU: 1 PID: 194 Comm: detach Not tainted 5.19.0-14184-g69dac8e431af #8
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
  rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014
  RIP: 0010:__cgroup_bpf_detach+0x1f2/0x2a0
  Code: 00 e8 92 60 30 00 84 c0 75 d8 4c 89 e0 31 f6 85 f6 74 19 42 f6 84
  28 48 05 00 00 02 75 0e 48 8b 80 c0 00 00 00 48 85 c0 75 e5 <0f> 0b 48
  8b 0c5
  RSP: 0018:ffffc9000055bdb0 EFLAGS: 00000246
  RAX: 0000000000000000 RBX: ffff888100ec0800 RCX: ffffc900000f1000
  RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffff888100ec4578
  RBP: 0000000000000000 R08: ffff888100ec0800 R09: 0000000000000040
  R10: 0000000000000000 R11: 0000000000000000 R12: ffff888100ec4000
  R13: 000000000000000d R14: ffffc90000199000 R15: ffff888100effb00
  FS:  00007f68213d2b80(0000) GS:ffff88813bc80000(0000)
  knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 000055f74a0e5850 CR3: 0000000102836000 CR4: 00000000000006e0
  Call Trace:
   <TASK>
   cgroup_bpf_prog_detach+0xcc/0x100
   __sys_bpf+0x2273/0x2a00
   __x64_sys_bpf+0x17/0x20
   do_syscall_64+0x3b/0x90
   entry_SYSCALL_64_after_hwframe+0x63/0xcd
  RIP: 0033:0x7f68214dbcb9
  Code: 08 44 89 e0 5b 41 5c c3 66 0f 1f 84 00 00 00 00 00 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 ff8
  RSP: 002b:00007ffeb487db68 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
  RAX: ffffffffffffffda RBX: 000000000000000b RCX: 00007f68214dbcb9
  RDX: 0000000000000090 RSI: 00007ffeb487db70 RDI: 0000000000000009
  RBP: 0000000000000003 R08: 0000000000000012 R09: 0000000b00000003
  R10: 00007ffeb487db70 R11: 0000000000000246 R12: 00007ffeb487dc20
  R13: 0000000000000004 R14: 0000000000000001 R15: 000055f74a1011b0
   </TASK>
  Modules linked in:
  ---[ end trace 0000000000000000 ]---

Repetition steps:

For the following cgroup tree,

  root
   |
  cg1
   |
  cg2

  1. attach prog2 to cg2, and then attach prog1 to cg1, both bpf progs
     attach type is NONE or OVERRIDE.
  2. write 1 to /proc/thread-self/fail-nth for failslab.
  3. detach prog1 for cg1, and then kernel BUG occur.

Failslab injection will cause kmalloc fail and fall back to
purge_effective_progs. The problem is that cg2 have attached another prog,
so when go through cg2 layer, iteration will add pos to 1, and subsequent
operations will be skipped by the following condition, and cg will meet
NULL in the end.

  `if (pos && !(cg->bpf.flags[atype] & BPF_F_ALLOW_MULTI))`

The NULL cg means no link or prog match, this is as expected, and it's not
a bug. So here just skip the no match situation.

Fixes: 4c46091ee9 ("bpf: Fix KASAN use-after-free Read in compute_effective_progs")
Signed-off-by: Pu Lehui <pulehui@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220813134030.1972696-1-pulehui@huawei.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-09-08 12:28:01 +02:00
..
bpf bpf, cgroup: Fix kernel BUG in purge_effective_progs 2022-09-08 12:28:01 +02:00
cgroup cgroup: Fix race condition at rebind_subsystems() 2022-08-31 17:16:33 +02:00
configs
debug lockdown: also lock down previous kgdb use 2022-05-25 09:57:37 +02:00
dma swiotlb: fail map correctly with failed io_tlb_default_mem 2022-08-17 14:24:07 +02:00
entry signal: Replace force_fatal_sig with force_exit_sig when in doubt 2021-11-25 09:49:07 +01:00
events perf/core: Fix data race between perf_event_set_output() and perf_mmap_close() 2022-07-29 17:25:11 +02:00
gcov Kconfig: Introduce ARCH_WANTS_NO_INSTR and CC_HAS_NO_PROFILE_FN_ATTR 2021-06-22 11:07:18 -07:00
irq irqdomain: Report irq number for NOMAP domains 2022-08-17 14:23:14 +02:00
kcsan LKMM updates: 2021-09-02 13:00:15 -07:00
livepatch livepatch: Fix build failure on 32 bits processors 2022-04-08 14:23:29 +02:00
locking locking/lockdep: Fix lockdep_init_map_*() confusion 2022-08-17 14:23:08 +02:00
power PM: hibernate: defer device probing when resuming from hibernation 2022-08-17 14:23:04 +02:00
printk printk: wake waiters for safe and NMI contexts 2022-06-09 10:22:49 +02:00
rcu rcutorture: Fix ksoftirqd boosting timing and iteration 2022-08-17 14:23:23 +02:00
sched sched/core: Do not requeue task on CPU excluded from cpus_mask 2022-08-17 14:24:15 +02:00
time timekeeping: contribute wall clock to rng on time change 2022-08-17 14:24:24 +02:00
trace ftrace: Fix NULL pointer dereference in is_ftrace_trampoline when ftrace is dead 2022-09-05 10:30:07 +02:00
.gitignore
acct.c kernel/acct.c: use dedicated helper to access rlimit values 2021-09-08 11:50:26 -07:00
async.c Revert "module, async: async_synchronize_full() on module init iff async is used" 2022-02-23 12:03:07 +01:00
audit_fsnotify.c audit: fix potential double free on error path from fsnotify_add_inode_mark 2022-08-31 17:16:33 +02:00
audit_tree.c audit: move put_tree() to avoid trim_trees refcount underflow and UAF 2021-08-24 18:52:36 -04:00
audit_watch.c
audit.c audit: improve audit queue handling when "audit=1" on cmdline 2022-02-08 18:34:03 +01:00
audit.h audit: log AUDIT_TIME_* records only from rules 2022-04-08 14:23:06 +02:00
auditfilter.c
auditsc.c audit: log AUDIT_TIME_* records only from rules 2022-04-08 14:23:06 +02:00
backtracetest.c
bounds.c
capability.c
cfi.c cfi: Fix __cfi_slowpath_diag RCU usage with cpuidle 2022-06-22 14:22:04 +02:00
compat.c arch: remove compat_alloc_user_space 2021-09-08 15:32:35 -07:00
configs.c
context_tracking.c
cpu_pm.c PM: cpu: Make notifier chain use a raw_spinlock_t 2021-08-16 18:55:32 +02:00
cpu.c random: clear fast pool, crng, and batches in cpuhp bring up 2022-05-30 09:29:09 +02:00
crash_core.c kernel/crash_core: suppress unknown crashkernel parameter warning 2021-12-29 12:28:49 +01:00
crash_dump.c
cred.c ucounts: Base set_cred_ucounts changes on the real user 2022-02-23 12:03:20 +01:00
delayacct.c
dma.c
exec_domain.c
exit.c fix race between exit_itimers() and /proc/pid/timers 2022-07-21 21:24:11 +02:00
extable.c
fail_function.c
fork.c sched: Fix yet more sched_fork() races 2022-03-08 19:12:49 +01:00
freezer.c sched: Add get_current_state() 2021-06-18 11:43:08 +02:00
futex.c futex: Remove unused variable 'vpid' in futex_proxy_trylock_atomic() 2021-09-03 23:00:22 +02:00
gen_kheaders.sh
groups.c
hung_task.c Merge branch 'akpm' (patches from Andrew) 2021-07-02 12:08:10 -07:00
iomem.c
irq_work.c
jump_label.c jump_label: Fix jump_label_text_reserved() vs __init 2021-07-05 10:46:20 +02:00
kallsyms.c module: add printk formats to add module build ID to stacktraces 2021-07-08 11:48:22 -07:00
kcmp.c
Kconfig.freezer
Kconfig.hz
Kconfig.locks locking/rwlock: Provide RT variant 2021-08-17 17:50:51 +02:00
Kconfig.preempt sched/core: Disable CONFIG_SCHED_CORE by default 2021-06-28 22:43:05 +02:00
kcov.c
kexec_core.c Merge branch 'rework/printk_safe-removal' into for-linus 2021-08-30 16:36:10 +02:00
kexec_elf.c
kexec_file.c ima: force signature verification when CONFIG_KEXEC_SIG is configured 2022-07-21 21:24:29 +02:00
kexec_internal.h
kexec.c kexec: avoid compat_alloc_user_space 2021-09-08 15:32:34 -07:00
kheaders.c
kmod.c
kprobes.c kprobes: don't call disarm_kprobe() for disabled kprobes 2022-09-05 10:30:12 +02:00
ksysfs.c
kthread.c Merge branch 'akpm' (patches from Andrew) 2021-06-29 17:29:11 -07:00
latencytop.c
Makefile static_call: Don't make __static_call_return0 static 2022-04-13 20:59:28 +02:00
module_signature.c
module_signing.c
module-internal.h
module.c module: fix [e_shstrndx].sh_size=0 OOB access 2022-07-12 16:35:09 +02:00
notifier.c notifier: Remove atomic_notifier_call_chain_robust() 2021-08-16 18:55:32 +02:00
nsproxy.c memcg: enable accounting for new namesapces and struct nsproxy 2021-09-03 09:58:12 -07:00
padata.c padata: Remove repeated verbose license text 2021-08-27 16:30:18 +08:00
panic.c Merge branch 'rework/printk_safe-removal' into for-linus 2021-08-30 16:36:10 +02:00
params.c params: lift param_set_uint_minmax to common code 2021-08-16 14:42:22 +02:00
pid_namespace.c memcg: enable accounting for new namesapces and struct nsproxy 2021-09-03 09:58:12 -07:00
pid.c kernel/pid.c: implement additional checks upon pidfd_create() parameters 2021-08-10 12:53:07 +02:00
profile.c profiling: fix shift too large makes kernel panic 2022-08-17 14:24:04 +02:00
ptrace.c ptrace: Reimplement PTRACE_KILL by always sending SIGKILL 2022-06-09 10:22:29 +02:00
range.c
reboot.c reboot: Add hardware protection power-off 2021-06-21 13:08:36 +01:00
regset.c
relay.c
resource_kunit.c
resource.c kernel/resource: fix kfree() of bootmem memory again 2022-04-08 14:23:43 +02:00
rseq.c rseq: Remove broken uapi field layout on 32-bit little endian 2022-04-08 14:23:10 +02:00
scftorture.c scftorture: Fix distribution of short handler delays 2022-06-09 10:22:46 +02:00
scs.c scs: Release kasan vmalloc poison in scs_free process 2021-11-18 19:16:29 +01:00
seccomp.c seccomp: Invalidate seccomp mode to catch death failures 2022-02-16 12:56:38 +01:00
signal.c signal handling: don't use BUG_ON() for debugging 2022-07-21 21:24:42 +02:00
smp.c locking/csd_lock: Change csdlock_debug from early_param to __setup 2022-08-17 14:24:24 +02:00
smpboot.c smpboot: Replace deprecated CPU-hotplug functions. 2021-08-10 14:57:42 +02:00
smpboot.h
softirq.c genirq: Change force_irqthreads to a static key 2021-08-10 22:50:07 +02:00
stackleak.c gcc-plugins/stackleak: Use noinstr in favor of notrace 2022-02-23 12:03:07 +01:00
stacktrace.c stacktrace: move filter_irq_stacks() to kernel/stacktrace.c 2022-04-13 20:59:28 +02:00
static_call_inline.c static_call: Don't make __static_call_return0 static 2022-04-13 20:59:28 +02:00
static_call.c static_call: Don't make __static_call_return0 static 2022-04-13 20:59:28 +02:00
stop_machine.c
sys_ni.c kernel/sys_ni: add compat entry for fadvise64_64 2022-08-31 17:16:33 +02:00
sys.c ucounts: Move RLIMIT_NPROC handling after set_user 2022-02-23 12:03:20 +01:00
sysctl-test.c kernel/sysctl-test: Remove some casts which are no-longer required 2021-06-23 16:41:24 -06:00
sysctl.c sysctl: move some boundary constants from sysctl.c to sysctl_vals 2022-07-29 17:25:11 +02:00
task_work.c
taskstats.c
test_kprobes.c
torture.c torture: Replace deprecated CPU-hotplug functions. 2021-08-10 10:48:07 -07:00
tracepoint.c tracepoint: Fix kerneldoc comments 2021-08-16 11:39:51 -04:00
tsacct.c taskstats: Cleanup the use of task->exit_code 2022-01-27 11:05:35 +01:00
ucount.c ucounts: Handle wrapping in is_ucounts_overlimit 2022-02-23 12:03:20 +01:00
uid16.c
uid16.h
umh.c
up.c
user_namespace.c ucounts: Fix systemd LimitNPROC with private users regression 2022-03-08 19:12:42 +01:00
user-return-notifier.c
user.c fs/epoll: use a per-cpu counter for user's watches count 2021-09-08 11:50:27 -07:00
usermode_driver.c Merge branch 'work.namei' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2021-07-03 11:41:14 -07:00
utsname_sysctl.c
utsname.c
watch_queue.c watch_queue: Fix missing locking in add_watch_to_object() 2022-08-03 12:03:43 +02:00
watchdog_hld.c
watchdog.c watchdog: export lockup_detector_reconfigure 2022-08-25 11:40:43 +02:00
workqueue_internal.h workqueue: Assign a color to barrier work items 2021-08-17 07:49:10 -10:00
workqueue.c workqueue: Fix unbind_workers() VS wq_worker_running() race 2022-01-16 09:12:41 +01:00