android_kernel_motorola_sm6375/kernel/trace
Repository files (latest commit first)
Filename Latest commit message Latest commit date
Steven Rostedt (VMware) d4238c7539 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 [#1] PREEMPT SMP
 CPU: 6 PID: 1810 Comm: cat Not tainted 5.13.0-rc5-test+ #61
 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: 79e577cbce ("tracing: Support string type key properly")
Fixes: 5967bd5c42 ("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 16:10:40 +02:00
..
blktrace.c blktrace: ensure our debugfs dir exists 2020-09-03 11:26:42 +02:00
bpf_trace.c tracepoint: Add tracepoint_probe_register_may_exist() for BPF tracing 2021-07-14 16:53:08 +02:00
fgraph.c fgraph: Initialize tracing_graph_pause at task creation 2021-02-10 09:25:29 +01:00
ftrace.c ftrace: Do not blindly read the ip address in ftrace_bug() 2021-06-16 11:59:45 +02:00
ftrace_internal.h
Kconfig tracing/kprobes: Do the notrace functions check without kprobes on ftrace 2021-01-19 18:26:12 +01:00
Makefile
power-traces.c
preemptirq_delay_test.c
ring_buffer.c tracing: Fix race in trace_open and buffer resize call 2021-01-30 13:54:10 +01:00
ring_buffer_benchmark.c
rpm-traces.c
trace.c tracing: Resize tgid_map to pid_max, not PID_MAX_DEFAULT 2021-07-19 08:53:17 +02:00
trace.h ftrace: Handle tracing when switching between context 2020-11-10 12:37:28 +01:00
trace_benchmark.c
trace_benchmark.h
trace_branch.c
trace_clock.c tracing: Do no increment trace_clock_global() by one 2021-06-23 14:41:28 +02:00
trace_dynevent.c tracing: Add tracing_check_open_get_tr() 2019-10-12 20:44:07 -04:00
trace_dynevent.h
trace_entries.h tracing: Set kernel_stack's caller size properly 2020-10-01 13:17:29 +02:00
trace_event_perf.c tracing: Fix race in perf_trace_buf initialization 2019-10-21 19:38:28 -04:00
trace_events.c tracing: Do not count ftrace events in top level enable output 2021-02-17 10:35:14 +01:00
trace_events_filter.c tracing: Avoid memory leak in process_system_preds() 2020-01-09 10:20:00 +01:00
trace_events_filter_test.h
trace_events_hist.c tracing: Do not reference char * as a string in histograms 2021-07-20 16:10:40 +02:00
trace_events_trigger.c tracing: Fix event trigger to accept redundant spaces 2020-06-30 15:37:10 -04:00
trace_export.c
trace_functions.c
trace_functions_graph.c
trace_hwlat.c tracing: Remove WARN_ON in start_thread() 2020-12-08 10:40:28 +01:00
trace_irqsoff.c
trace_kdb.c
trace_kprobe.c tracing/kprobe: Fix to support kretprobe events on unloaded modules 2021-02-13 13:52:54 +01:00
trace_kprobe_selftest.c
trace_kprobe_selftest.h
trace_mmiotrace.c
trace_nop.c
trace_output.c tracing: Make the space reserved for the pid wider 2020-10-07 08:01:27 +02:00
trace_output.h
trace_preemptirq.c lockdep: fix order in trace_hardirqs_off_caller() 2020-10-01 13:18:14 +02:00
trace_printk.c tracing: Add locked_down checks to the open calls of files created for tracefs 2019-10-12 20:48:06 -04:00
trace_probe.c tracing/probe: Fix memleak in fetch_op_data operations 2020-06-24 17:50:51 +02:00
trace_probe.h tracing/uprobe: Fix to make trace_uprobe_filter alignment safe 2020-02-05 21:22:53 +00:00
trace_probe_tmpl.h
trace_sched_switch.c tracing: Fix sched switch start/stop refcount racy updates 2020-02-11 04:35:07 -08:00
trace_sched_wakeup.c kernel/trace: Fix do not unregister tracepoints when register sched_migrate_task fail 2020-01-14 20:08:22 +01:00
trace_selftest.c ftrace: Handle tracing when switching between context 2020-11-10 12:37:28 +01:00
trace_selftest_dynamic.c
trace_seq.c
trace_stack.c tracing: Have stack tracer compile when MCOUNT_INSN_SIZE is not defined 2020-01-14 20:08:22 +01:00
trace_stat.c tracing: Fix very unlikely race of registering two stat tracers 2020-02-24 08:36:30 +01:00
trace_stat.h
trace_syscalls.c
trace_uprobe.c tracing/probe: Fix bpf_task_fd_query() for kprobes and uprobes 2020-06-24 17:50:43 +02:00
tracing_map.c tracing: Have the histogram compare functions convert to u64 first 2020-01-09 10:20:00 +01:00
tracing_map.h