sst-linux/kernel
GUO Zihua 9c3906c373 ima: Avoid blocking in RCU read-side critical section
commit 9a95c5bfbf02a0a7f5983280fe284a0ff0836c34 upstream.

A panic happens in ima_match_policy:

BUG: unable to handle kernel NULL pointer dereference at 0000000000000010
PGD 42f873067 P4D 0
Oops: 0000 [#1] SMP NOPTI
CPU: 5 PID: 1286325 Comm: kubeletmonit.sh
Kdump: loaded Tainted: P
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
               BIOS 0.0.0 02/06/2015
RIP: 0010:ima_match_policy+0x84/0x450
Code: 49 89 fc 41 89 cf 31 ed 89 44 24 14 eb 1c 44 39
      7b 18 74 26 41 83 ff 05 74 20 48 8b 1b 48 3b 1d
      f2 b9 f4 00 0f 84 9c 01 00 00 <44> 85 73 10 74 ea
      44 8b 6b 14 41 f6 c5 01 75 d4 41 f6 c5 02 74 0f
RSP: 0018:ff71570009e07a80 EFLAGS: 00010207
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000200
RDX: ffffffffad8dc7c0 RSI: 0000000024924925 RDI: ff3e27850dea2000
RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffffabfce739
R10: ff3e27810cc42400 R11: 0000000000000000 R12: ff3e2781825ef970
R13: 00000000ff3e2785 R14: 000000000000000c R15: 0000000000000001
FS:  00007f5195b51740(0000)
GS:ff3e278b12d40000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000010 CR3: 0000000626d24002 CR4: 0000000000361ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 ima_get_action+0x22/0x30
 process_measurement+0xb0/0x830
 ? page_add_file_rmap+0x15/0x170
 ? alloc_set_pte+0x269/0x4c0
 ? prep_new_page+0x81/0x140
 ? simple_xattr_get+0x75/0xa0
 ? selinux_file_open+0x9d/0xf0
 ima_file_check+0x64/0x90
 path_openat+0x571/0x1720
 do_filp_open+0x9b/0x110
 ? page_counter_try_charge+0x57/0xc0
 ? files_cgroup_alloc_fd+0x38/0x60
 ? __alloc_fd+0xd4/0x250
 ? do_sys_open+0x1bd/0x250
 do_sys_open+0x1bd/0x250
 do_syscall_64+0x5d/0x1d0
 entry_SYSCALL_64_after_hwframe+0x65/0xca

Commit c7423dbdbc9e ("ima: Handle -ESTALE returned by
ima_filter_rule_match()") introduced call to ima_lsm_copy_rule within a
RCU read-side critical section which contains kmalloc with GFP_KERNEL.
This implies a possible sleep and violates limitations of RCU read-side
critical sections on non-PREEMPT systems.

Sleeping within RCU read-side critical section might cause
synchronize_rcu() returning early and break RCU protection, allowing a
UAF to happen.

The root cause of this issue could be described as follows:
|	Thread A	|	Thread B	|
|			|ima_match_policy	|
|			|  rcu_read_lock	|
|ima_lsm_update_rule	|			|
|  synchronize_rcu	|			|
|			|    kmalloc(GFP_KERNEL)|
|			|      sleep		|
==> synchronize_rcu returns early
|  kfree(entry)		|			|
|			|    entry = entry->next|
==> UAF happens and entry now becomes NULL (or could be anything).
|			|    entry->action	|
==> Accessing entry might cause panic.

To fix this issue, we are converting all kmalloc that is called within
RCU read-side critical section to use GFP_ATOMIC.

Fixes: c7423dbdbc9e ("ima: Handle -ESTALE returned by ima_filter_rule_match()")
Cc: stable@vger.kernel.org
Signed-off-by: GUO Zihua <guozihua@huawei.com>
Acked-by: John Johansen <john.johansen@canonical.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
[PM: fixed missing comment, long lines, !CONFIG_IMA_LSM_RULES case]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-07-11 12:47:16 +02:00
..
bpf bpf: Mark bpf prog stack with kmsan_unposion_memory in interpreter mode 2024-07-05 09:31:48 +02:00
cgroup sched/fair: Allow disabling sched_balance_newidle with sched_relax_domain_level 2024-06-12 11:03:33 +02:00
configs
debug kdb: Use format-specifiers rather than memset() for padding in kdb_read() 2024-06-16 13:41:40 +02:00
dma dma-mapping: benchmark: handle NUMA_NO_NODE correctly 2024-06-12 11:03:54 +02:00
entry entry: Respect changes to system call number by trace_sys_enter() 2024-04-03 15:19:44 +02:00
events perf/core: Fix missing wakeup when waiting for context reference 2024-06-21 14:35:55 +02:00
futex futex: Don't include process MM in futex key on no-MMU 2023-11-20 11:51:50 +01:00
gcov gcov: add support for GCC 14 2024-06-27 13:46:22 +02:00
irq genirq/cpuhotplug, x86/vector: Prevent vector leak during CPU offline 2024-06-12 11:03:01 +02:00
kcsan
livepatch livepatch: Fix missing newline character in klp_resolve_symbols() 2023-11-20 11:52:10 +01:00
locking locking/mutex: Introduce devm_mutex_init() 2024-07-11 12:47:04 +02:00
module modules: wait do_free_init correctly 2024-03-26 18:20:52 -04:00
power PM: s2idle: Make sure CPUs will wakeup directly on resume 2024-04-17 11:18:22 +02:00
printk printk: Update @console_may_schedule in console_trylock_spinning() 2024-04-03 15:19:44 +02:00
rcu rcutorture: Fix invalid context warning when enable srcu barrier testing 2024-06-27 13:46:15 +02:00
sched sched/core: Fix incorrect initialization of the 'burst' parameter in cpu_max_write() 2024-06-12 11:03:33 +02:00
time tick/nohz_full: Don't abuse smp_call_function_single() in tick_setup_device() 2024-06-21 14:35:59 +02:00
trace tracing: Add MODULE_DESCRIPTION() to preemptirq_delay_test 2024-06-27 13:46:23 +02:00
.gitignore
acct.c
async.c async: Introduce async_schedule_dev_nocall() 2024-01-31 16:17:00 -08:00
audit_fsnotify.c
audit_tree.c
audit_watch.c audit: don't WARN_ON_ONCE(!current->mm) in audit_exe_compare() 2023-11-28 17:07:08 +00:00
audit.c audit: Send netlink ACK before setting connection in auditd_set 2024-02-05 20:12:47 +00:00
audit.h
auditfilter.c ima: Avoid blocking in RCU read-side critical section 2024-07-11 12:47:16 +02:00
auditsc.c audit,io_uring: io_uring openat triggers audit reference count underflow 2023-10-25 12:03:04 +02:00
backtracetest.c
bounds.c bounds: Use the right number of bits for power-of-two CONFIG_NR_CPUS 2024-05-02 16:29:32 +02:00
capability.c
cfi.c
compat.c
configs.c
context_tracking.c
cpu_pm.c
cpu.c cpu/hotplug: Fix dynstate assignment in __cpuhp_setup_state_cpuslocked() 2024-07-05 09:31:56 +02:00
crash_core.c
crash_dump.c
cred.c cred: switch to using atomic_long_t 2023-12-20 17:00:20 +01:00
delayacct.c
dma.c
exec_domain.c
exit.c mm: optimize the redundant loop of mm_update_owner_next() 2024-07-11 12:47:13 +02:00
extable.c
fail_function.c
fork.c Revert "fork: defer linking file vma until vma is fully initialized" 2024-06-21 14:35:59 +02:00
freezer.c
gen_kheaders.sh kheaders: explicitly define file modes for archived headers 2024-06-27 13:46:24 +02:00
groups.c
hung_task.c
iomem.c
irq_work.c
jump_label.c
kallsyms_internal.h kallsyms: Reduce the memory occupied by kallsyms_seqs_of_names[] 2023-10-25 12:03:16 +02:00
kallsyms.c kallsyms: Add helper kallsyms_on_each_match_symbol() 2023-10-25 12:03:16 +02:00
kcmp.c
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt
kcov.c kcov: don't lose track of remote references during softirqs 2024-06-27 13:46:22 +02:00
kexec_core.c
kexec_elf.c
kexec_file.c
kexec_internal.h
kexec.c kernel: kexec: copy user-array safely 2023-11-28 17:06:57 +00:00
kheaders.c
kmod.c
kprobes.c kprobes: Fix possible use-after-free issue on kprobe registration 2024-04-17 11:18:27 +02:00
ksysfs.c
kthread.c
latencytop.c
Makefile kernel/numa.c: Move logging out of numa.h 2024-06-12 11:03:16 +02:00
module_signature.c
notifier.c
nsproxy.c
numa.c kernel/numa.c: Move logging out of numa.h 2024-06-12 11:03:16 +02:00
padata.c padata: Disable BH when taking works lock on MT path 2024-06-27 13:46:14 +02:00
panic.c panic: Flush kernel log buffer at the end 2024-04-13 13:04:54 +02:00
params.c
pid_namespace.c zap_pid_ns_processes: clear TIF_NOTIFY_SIGNAL along with TIF_SIGPENDING 2024-06-21 14:36:01 +02:00
pid.c
profile.c
ptrace.c
range.c
reboot.c kernel/reboot: emergency_restart: Set correct system_state 2023-11-28 17:07:13 +00:00
regset.c
relay.c
resource_kunit.c
resource.c
rseq.c
scftorture.c scftorture: Forgive memory-allocation failure if KASAN 2023-09-23 11:11:00 +02:00
scs.c
seccomp.c
signal.c
smp.c smp,csd: Throw an error if a CSD lock is stuck for too long 2023-11-28 17:06:55 +00:00
smpboot.c
smpboot.h
softirq.c softirq: Fix suspicious RCU usage in __do_softirq() 2024-06-12 11:03:01 +02:00
stackleak.c
stacktrace.c
static_call_inline.c
static_call.c
stop_machine.c
sys_ni.c syscalls: fix compat_sys_io_pgetevents_time64 usage 2024-07-05 09:31:59 +02:00
sys.c getrusage: use sig->stats_lock rather than lock_task_sighand() 2024-03-15 10:48:22 -04:00
sysctl-test.c
sysctl.c
task_work.c
taskstats.c
torture.c
tracepoint.c
tsacct.c
ucount.c
uid16.c
uid16.h
umh.c
up.c
user_namespace.c
user-return-notifier.c
user.c
usermode_driver.c
utsname_sysctl.c
utsname.c
watch_queue.c kernel: watch_queue: copy user-array safely 2023-11-28 17:06:57 +00:00
watchdog_hld.c
watchdog.c watchdog: move softlockup_panic back to early_param 2023-11-28 17:07:09 +00:00
workqueue_internal.h
workqueue.c workqueue: Provide one lock class key per work_on_cpu() callsite 2023-11-28 17:06:55 +00:00