linux-uconsole/kernel/trace
Yang Jihong dbd8c8fc60 ftrace: Fix NULL pointer dereference in is_ftrace_trampoline when ftrace is dead
commit c3b0f72e80 upstream.

ftrace_startup does not remove ops from ftrace_ops_list when
ftrace_startup_enable fails:

register_ftrace_function
  ftrace_startup
    __register_ftrace_function
      ...
      add_ftrace_ops(&ftrace_ops_list, ops)
      ...
    ...
    ftrace_startup_enable // if ftrace failed to modify, ftrace_disabled is set to 1
    ...
  return 0 // ops is in the ftrace_ops_list.

When ftrace_disabled = 1, unregister_ftrace_function simply returns without doing anything:
unregister_ftrace_function
  ftrace_shutdown
    if (unlikely(ftrace_disabled))
            return -ENODEV;  // return here, __unregister_ftrace_function is not executed,
                             // as a result, ops is still in the ftrace_ops_list
    __unregister_ftrace_function
    ...

If ops is dynamically allocated, it will be free later, in this case,
is_ftrace_trampoline accesses NULL pointer:

is_ftrace_trampoline
  ftrace_ops_trampoline
    do_for_each_ftrace_op(op, ftrace_ops_list) // OOPS! op may be NULL!

Syzkaller reports as follows:
[ 1203.506103] BUG: kernel NULL pointer dereference, address: 000000000000010b
[ 1203.508039] #PF: supervisor read access in kernel mode
[ 1203.508798] #PF: error_code(0x0000) - not-present page
[ 1203.509558] PGD 800000011660b067 P4D 800000011660b067 PUD 130fb8067 PMD 0
[ 1203.510560] Oops: 0000 [#1] SMP KASAN PTI
[ 1203.511189] CPU: 6 PID: 29532 Comm: syz-executor.2 Tainted: G    B   W         5.10.0 #8
[ 1203.512324] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
[ 1203.513895] RIP: 0010:is_ftrace_trampoline+0x26/0xb0
[ 1203.514644] Code: ff eb d3 90 41 55 41 54 49 89 fc 55 53 e8 f2 00 fd ff 48 8b 1d 3b 35 5d 03 e8 e6 00 fd ff 48 8d bb 90 00 00 00 e8 2a 81 26 00 <48> 8b ab 90 00 00 00 48 85 ed 74 1d e8 c9 00 fd ff 48 8d bb 98 00
[ 1203.518838] RSP: 0018:ffffc900012cf960 EFLAGS: 00010246
[ 1203.520092] RAX: 0000000000000000 RBX: 000000000000007b RCX: ffffffff8a331866
[ 1203.521469] RDX: 0000000000000000 RSI: 0000000000000008 RDI: 000000000000010b
[ 1203.522583] RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff8df18b07
[ 1203.523550] R10: fffffbfff1be3160 R11: 0000000000000001 R12: 0000000000478399
[ 1203.524596] R13: 0000000000000000 R14: ffff888145088000 R15: 0000000000000008
[ 1203.525634] FS:  00007f429f5f4700(0000) GS:ffff8881daf00000(0000) knlGS:0000000000000000
[ 1203.526801] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1203.527626] CR2: 000000000000010b CR3: 0000000170e1e001 CR4: 00000000003706e0
[ 1203.528611] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 1203.529605] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

Therefore, when ftrace_startup_enable fails, we need to rollback registration
process and remove ops from ftrace_ops_list.

Link: https://lkml.kernel.org/r/20220818032659.56209-1-yangjihong1@huawei.com

Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Yang Jihong <yangjihong1@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-09-05 10:28:56 +02:00
..
blktrace.c blktrace: Trace remapped requests correctly 2022-08-21 15:15:36 +02:00
bpf_trace.c bpf: Remove config check to enable bpf support for branch records 2022-01-27 10:53:54 +01:00
bpf_trace.h
fgraph.c fgraph: Initialize tracing_graph_pause at task creation 2021-02-10 09:29:16 +01:00
ftrace.c ftrace: Fix NULL pointer dereference in is_ftrace_trampoline when ftrace is dead 2022-09-05 10:28:56 +02:00
ftrace_internal.h
Kconfig tracing/kprobes: Do the notrace functions check without kprobes on ftrace 2021-01-19 18:27:19 +01:00
kprobe_event_gen_test.c
Makefile
power-traces.c
preemptirq_delay_test.c
ring_buffer.c ring-buffer: Protect ring_buffer_reset() from reentrancy 2021-11-18 14:03:49 +01:00
ring_buffer_benchmark.c
rpm-traces.c
synth_event_gen_test.c tracing: Add support for dynamic strings to synthetic events 2020-10-05 19:32:18 -04:00
trace.c tracing: Avoid adding tracer option before update_tracer_options 2022-06-14 18:32:38 +02:00
trace.h tracing: Fix pid filtering when triggers are attached 2021-12-01 09:19:01 +01:00
trace_benchmark.c
trace_benchmark.h
trace_boot.c tracing/boot: Fix a hist trigger dependency for boot time tracing 2021-09-22 12:28:03 +02:00
trace_branch.c
trace_clock.c tracing: Do no increment trace_clock_global() by one 2021-06-23 14:42:50 +02:00
trace_dynevent.c tracing: Delete repeated words in comments 2020-09-21 21:06:02 -04:00
trace_dynevent.h
trace_entries.h
trace_event_perf.c
trace_events.c tracing: Have filter accept "common_cpu" to be consistent 2022-08-25 11:37:51 +02:00
trace_events_filter.c tracing: Add ustring operation to filtering string pointers 2022-03-08 19:09:31 +01:00
trace_events_filter_test.h
trace_events_hist.c tracing/histograms: Fix memory leak problem 2022-07-21 21:19:59 +02:00
trace_events_inject.c
trace_events_synth.c tracing: Make -ENOMEM the default error for parse_synth_field() 2020-11-02 15:58:32 -05:00
trace_events_trigger.c tracing: Dump stacktrace trigger to the corresponding instance 2022-04-27 13:53:46 +02:00
trace_export.c treewide: Convert macro and uses of __section(foo) to __section("foo") 2020-10-25 14:51:49 -07:00
trace_functions.c tracing: Have all levels of checks prevent recursion 2021-10-27 09:56:56 +02:00
trace_functions_graph.c tracing: make tracing_init_dentry() returns an integer instead of a d_entry pointer 2020-09-18 22:17:14 -04:00
trace_hwlat.c tracing: Remove WARN_ON in start_thread() 2020-11-30 21:43:07 -05:00
trace_irqsoff.c tracing: Use pause-on-trace with the latency tracers 2021-02-10 09:29:16 +01:00
trace_kdb.c
trace_kprobe.c tracing: Fix return value of __setup handlers 2022-03-08 19:09:38 +01:00
trace_kprobe_selftest.c
trace_kprobe_selftest.h
trace_mmiotrace.c
trace_nop.c
trace_output.c
trace_output.h
trace_preemptirq.c
trace_printk.c Updates for tracing and bootconfig: 2020-10-15 15:51:28 -07:00
trace_probe.c tracing/probes: Have kprobes and uprobes use $COMM too 2022-08-25 11:38:23 +02:00
trace_probe.h tracing/probes: Reject events which have the same name of existing one 2021-09-22 12:28:00 +02:00
trace_probe_tmpl.h
trace_sched_switch.c
trace_sched_wakeup.c
trace_selftest.c tracing: Disable ftrace selftests when any tracer is running 2020-12-30 11:54:28 +01:00
trace_selftest_dynamic.c
trace_seq.c
trace_stack.c tracing: make tracing_init_dentry() returns an integer instead of a d_entry pointer 2020-09-18 22:17:14 -04:00
trace_stat.c tracing: make tracing_init_dentry() returns an integer instead of a d_entry pointer 2020-09-18 22:17:14 -04:00
trace_stat.h
trace_synth.h tracing: Synthetic event field_pos is an index not a boolean 2021-07-28 14:35:45 +02:00
trace_syscalls.c
trace_uprobe.c tracing/uprobe: Fix uprobe_perf_open probes iteration 2021-12-01 09:19:01 +01:00
tracing_map.c tracing: Fix a kmemleak false positive in tracing_map 2021-12-17 10:14:40 +01:00
tracing_map.h