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Steven Rostedt (VMware) 1834fbbd66 tracing: Do not reference char * as a string in histograms 
commit 704adfb5a9978462cd861f170201ae2b5e3d3a80 upstream.

The histogram logic was allowing events with char * pointers to be used as
normal strings. But it was easy to crash the kernel with:

 # echo 'hist:keys=filename' > events/syscalls/sys_enter_openat/trigger

And open some files, and boom!

 BUG: unable to handle page fault for address: 00007f2ced0c3280
 #PF: supervisor read access in kernel mode
 #PF: error_code(0x0000) - not-present page
 PGD 1173fa067 P4D 1173fa067 PUD 1171b6067 PMD 1171dd067 PTE 0
 Oops: 0000 [] PREEMPT SMP
 CPU: 6 PID: 1810 Comm: cat Not tainted 5.13.0-rc5-test+ 
 Hardware name: Hewlett-Packard HP Compaq Pro 6300 SFF/339A, BIOS K01
v03.03 07/14/2016
 RIP: 0010:strlen+0x0/0x20
 Code: f6 82 80 2a 0b a9 20 74 11 0f b6 50 01 48 83 c0 01 f6 82 80 2a 0b
a9 20 75 ef c3 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 <80> 3f 00 74
10 48 89 f8 48 83 c0 01 80 38 00 75 f7 48 29 f8 c3

 RSP: 0018:ffffbdbf81567b50 EFLAGS: 00010246
 RAX: 0000000000000003 RBX: ffff93815cdb3800 RCX: ffff9382401a22d0
 RDX: 0000000000000100 RSI: 0000000000000000 RDI: 00007f2ced0c3280
 RBP: 0000000000000100 R08: ffff9382409ff074 R09: ffffbdbf81567c98
 R10: ffff9382409ff074 R11: 0000000000000000 R12: ffff9382409ff074
 R13: 0000000000000001 R14: ffff93815a744f00 R15: 00007f2ced0c3280
 FS:  00007f2ced0f8580(0000) GS:ffff93825a800000(0000)
knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 00007f2ced0c3280 CR3: 0000000107069005 CR4: 00000000001706e0
 Call Trace:
  event_hist_trigger+0x463/0x5f0
  ? find_held_lock+0x32/0x90
  ? sched_clock_cpu+0xe/0xd0
  ? lock_release+0x155/0x440
  ? kernel_init_free_pages+0x6d/0x90
  ? preempt_count_sub+0x9b/0xd0
  ? kernel_init_free_pages+0x6d/0x90
  ? get_page_from_freelist+0x12c4/0x1680
  ? __rb_reserve_next+0xe5/0x460
  ? ring_buffer_lock_reserve+0x12a/0x3f0
  event_triggers_call+0x52/0xe0
  ftrace_syscall_enter+0x264/0x2c0
  syscall_trace_enter.constprop.0+0x1ee/0x210
  do_syscall_64+0x1c/0x80
  entry_SYSCALL_64_after_hwframe+0x44/0xae

Where it triggered a fault on strlen(key) where key was the filename.

The reason is that filename is a char * to user space, and the histogram
code just blindly dereferenced it, with obvious bad results.

I originally tried to use strncpy_from_user/kernel_nofault() but found
that there's other places that its dereferenced and not worth the effort.

Just do not allow "char *" to act like strings.

Link: https://lkml.kernel.org/r/20210715000206.025df9d2@rorschach.local.home

Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Tzvetomir Stoyanov <tz.stoyanov@gmail.com>
Cc: stable@vger.kernel.org
Acked-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Tom Zanussi <zanussi@kernel.org>
Fixes: 79e577cbce4c4 ("tracing: Support string type key properly")
Fixes: 5967bd5c4239 ("tracing: Let filter_assign_type() detect FILTER_PTR_STRING")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-07-20 16:16:07 +02:00
..
bpf
bpf: Add BPF_F_ANY_ALIGNMENT.
2021-06-10 13:24:08 +02:00
cgroup
cgroup1: don't allow '\n' in renaming
2021-06-16 11:54:59 +02:00
configs
kconfig: tinyconfig: remove stale stack protector fixups
2018-06-15 07:15:28 +09:00
debug
kdb: Make memory allocations more robust
2021-03-04 09:39:31 +01:00
dma
swiotlb: fix "x86: Don't panic if can not alloc buffer for swiotlb"
2020-11-18 19:18:51 +01:00
events
perf: Fix data race between pin_count increment/decrement
2021-06-16 11:55:01 +02:00
gcov
gcov: add support for GCC 10.1
2020-09-17 13:45:31 +02:00
irq
genirq/matrix: Prevent allocation counter corruption
2021-05-22 10:59:14 +02:00
livepatch
livepatch: Nullify obj->mod in klp_module_coming()'s error path
2019-10-07 18:57:10 +02:00
locking
locking/mutex: clear MUTEX_FLAGS if wait_list is empty due to signal
2021-05-26 11:48:32 +02:00
power
PM: hibernate: flush swap writer after marking
2021-02-03 23:23:24 +01:00
printk
printk: fix deadlock when kernel panic
2021-03-04 09:39:57 +01:00
rcu
rcu: Avoid data-race in rcu_gp_fqs_check_wake()
2020-02-11 04:33:55 -08:00
sched
sched/fair: Fix ascii art by relpacing tabs
2021-07-20 16:15:44 +02:00
time
clocksource: Retry clock read if long delays detected
2021-07-20 16:15:46 +02:00
trace
tracing: Do not reference char * as a string in histograms
2021-07-20 16:16:07 +02:00
.gitignore
…
acct.c
acct_on(): don't mess with freeze protection
2019-05-31 06:46:05 -07:00
async.c
…
audit_fsnotify.c
fsnotify: add fsnotify_add_inode_mark() wrappers
2018-05-18 14:58:22 +02:00
audit_tree.c
audit: Embed key into chunk
2019-12-13 08:51:11 +01:00
audit_watch.c
audit: CONFIG_CHANGE don't log internal bookkeeping as an event
2020-10-01 13:14:33 +02:00
audit.c
audit: fix a net reference leak in audit_list_rules_send()
2020-06-22 09:05:13 +02:00
audit.h
audit: fix a net reference leak in audit_list_rules_send()
2020-06-22 09:05:13 +02:00
auditfilter.c
audit: fix a net reference leak in audit_list_rules_send()
2020-06-22 09:05:13 +02:00
auditsc.c
audit: print empty EXECVE args
2019-12-01 09:17:17 +01:00
backtracetest.c
…
bounds.c
kbuild: fix kernel/bounds.c 'W=1' warning
2018-11-13 11:08:47 -08:00
capability.c
LSM: generalize flag passing to security_capable
2020-01-23 08:21:29 +01:00
compat.c
make 'user_access_begin()' do 'access_ok()'
2020-06-22 09:04:58 +02:00
configs.c
…
context_tracking.c
…
cpu_pm.c
kernel/cpu_pm: Fix uninitted local in cpu_pm
2020-06-22 09:05:28 +02:00
cpu.c
cpu/hotplug: Cure the cpusets trainwreck
2021-07-20 16:16:04 +02:00
crash_core.c
kernel/crash_core.c: print timestamp using time64_t
2018-08-22 10:52:47 -07:00
crash_dump.c
…
cred.c
memcg: account security cred as well to kmemcg
2020-01-09 10:19:00 +01:00
delayacct.c
…
dma.c
proc: introduce proc_create_single{,_data}
2018-05-16 07:23:35 +02:00
exec_domain.c
proc: introduce proc_create_single{,_data}
2018-05-16 07:23:35 +02:00
exit.c
futex: Mark the begin of futex exit explicitly
2021-01-30 13:32:11 +01:00
extable.c
…
fail_function.c
fail_function: Remove a redundant mutex unlock
2020-11-24 13:27:23 +01:00
fork.c
futex: Split futex_mm_release() for exit/exec
2021-01-30 13:32:11 +01:00
freezer.c
PM / reboot: Eliminate race between reboot and suspend
2018-08-06 12:35:20 +02:00
futex.c
mm, futex: fix shared futex pgoff on shmem huge page
2021-07-11 12:49:30 +02:00
groups.c
…
hung_task.c
kernel: hung_task.c: disable on suspend
2019-04-20 09:16:02 +02:00
iomem.c
memremap: split devm_memremap_pages() and memremap() infrastructure
2018-05-15 23:08:33 -07:00
irq_work.c
irq_work: Do not raise an IPI when queueing work on the local CPU
2019-05-31 06:46:19 -07:00
jump_label.c
locking/static_key: Fix false positive warnings on concurrent dec/inc
2021-03-04 09:39:30 +01:00
kallsyms.c
kallsyms: Refactor kallsyms_show_value() to take cred
2020-07-16 08:17:26 +02:00
kcmp.c
…
Kconfig.freezer
…
Kconfig.hz
…
Kconfig.locks
…
Kconfig.preempt
kconfig: include kernel/Kconfig.preempt from init/Kconfig
2018-08-02 08:06:54 +09:00
kcov.c
kernel/kcov.c: mark write_comp_data() as notrace
2019-02-12 19:47:20 +01:00
kexec_core.c
kernel: kexec: remove the lock operation of system_transition_mutex
2021-02-03 23:23:23 +01:00
kexec_file.c
kernel: kexec_file: fix error return code of kexec_calculate_store_digests()
2021-05-22 10:59:44 +02:00
kexec_internal.h
…
kexec.c
kexec: add call to LSM hook in original kexec_load syscall
2018-07-16 12:31:57 -07:00
kmod.c
kmod: make request_module() return an error when autoloading is disabled
2020-04-17 10:48:52 +02:00
kprobes.c
tracing/kprobe: Fix to support kretprobe events on unloaded modules
2021-02-13 13:51:13 +01:00
ksysfs.c
…
kthread.c
kthread: prevent deadlock when kthread_mod_delayed_work() races with kthread_cancel_delayed_work_sync()
2021-07-11 12:49:31 +02:00
latencytop.c
…
Makefile
elfcore: fix building with clang
2021-02-10 09:21:06 +01:00
memremap.c
mm/memory_hotplug: shrink zones when offlining memory
2020-01-29 16:43:27 +01:00
module_signing.c
modsign: log module name in the event of an error
2018-07-02 11:36:17 +02:00
module-internal.h
modsign: log module name in the event of an error
2018-07-02 11:36:17 +02:00
module.c
module: limit enabling module.sig_enforce
2021-06-30 08:48:28 -04:00
notifier.c
x86/mm: split vmalloc_sync_all()
2020-03-25 08:06:13 +01:00
nsproxy.c
…
padata.c
padata: purge get_cpu and reorder_via_wq from padata_do_serial
2020-05-27 17:37:36 +02:00
panic.c
kernel/panic.c: do not append newline to the stack protector panic string
2019-12-01 09:17:10 +01:00
params.c
…
pid_namespace.c
signal/pid_namespace: Fix reboot_pid_ns to use send_sig not force_sig
2019-07-26 09:14:01 +02:00
pid.c
Fix failure path in alloc_pid()
2019-01-13 09:51:06 +01:00
profile.c
…
ptrace.c
ptrace: make ptrace() fail if the tracee changed its pid unexpectedly
2021-05-26 11:48:32 +02:00
range.c
…
reboot.c
reboot: fix overflow parsing reboot cpu number
2020-11-18 19:18:52 +01:00
relay.c
kernel/relay.c: fix memleak on destroy relay channel
2020-08-26 10:30:59 +02:00
resource.c
resource: fix locking in find_next_iomem_res()
2019-09-16 08:22:20 +02:00
rseq.c
rseq: uapi: Declare rseq_cs field as union, update includes
2018-07-10 22:18:52 +02:00
seccomp.c
seccomp: Add missing return in non-void function
2021-03-04 09:39:54 +01:00
signal.c
ptrace: fix task_join_group_stop() for the case when current is traced
2020-11-10 12:35:53 +01:00
smp.c
smp: Fix smp_call_function_single_async prototype
2021-05-22 10:59:39 +02:00
smpboot.c
kthread: Extract KTHREAD_IS_PER_CPU
2021-02-07 14:48:38 +01:00
smpboot.h
…
softirq.c
nohz: Fix missing tick reprogram when interrupting an inline softirq
2018-08-03 15:52:10 +02:00
stacktrace.c
…
stop_machine.c
Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2018-08-13 11:25:07 -07:00
sys_ni.c
Merge branch 'core-rseq-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2018-06-10 10:17:09 -07:00
sys.c
kernel/sys.c: avoid copying possible padding bytes in copy_to_user
2020-10-01 13:14:29 +02:00
sysctl_binary.c
…
sysctl.c
sysctl: handle overflow in proc_get_long
2021-02-07 14:48:37 +01:00
task_work.c
…
taskstats.c
taskstats: fix data-race
2020-01-09 10:18:59 +01:00
test_kprobes.c
kprobes: Remove jprobe API implementation
2018-06-21 12:33:05 +02:00
torture.c
torture: Keep old-school dmesg format
2018-06-25 11:30:10 -07:00
tracepoint.c
tracepoint: Add tracepoint_probe_register_may_exist() for BPF tracing
2021-07-20 16:15:42 +02:00
tsacct.c
…
ucount.c
…
uid16.c
…
uid16.h
…
umh.c
usermodehelper: reset umask to default before executing user process
2020-10-14 10:31:21 +02:00
up.c
smp: Fix smp_call_function_single_async prototype
2021-05-22 10:59:39 +02:00
user_namespace.c
userns: also map extents in the reverse map to kernel IDs
2018-11-13 11:09:00 -08:00
user-return-notifier.c
…
user.c
userns: use irqsave variant of refcount_dec_and_lock()
2018-08-22 10:52:47 -07:00
utsname_sysctl.c
sys: don't hold uts_sem while accessing userspace memory
2018-08-11 02:05:53 -05:00
utsname.c
…
watchdog_hld.c
watchdog: Mark watchdog touch functions as notrace
2018-08-30 12:56:40 +02:00
watchdog.c
watchdog/softlockup: Enforce that timestamp is valid on boot
2020-02-24 08:34:49 +01:00
workqueue_internal.h
workqueue: Set worker->desc to workqueue name by default
2018-05-18 08:47:13 -07:00
workqueue.c
wq: handle VM suspension in stall detection
2021-06-16 11:54:57 +02:00