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Zhihao Cheng ebb8d26d93 blktrace: Fix uaf in blk_trace access after removing by sysfs 
[ Upstream commit 5afedf670caf30a2b5a52da96eb7eac7dee6a9c9 ]

There is an use-after-free problem triggered by following process:

      P1(sda)				P2(sdb)
			echo 0 > /sys/block/sdb/trace/enable
			  blk_trace_remove_queue
			    synchronize_rcu
			    blk_trace_free
			      relay_close
rcu_read_lock
__blk_add_trace
  trace_note_tsk
  (Iterate running_trace_list)
			        relay_close_buf
				  relay_destroy_buf
				    kfree(buf)
    trace_note(sdb's bt)
      relay_reserve
        buf->offset <- nullptr deference (use-after-free) !!!
rcu_read_unlock

[  502.714379] BUG: kernel NULL pointer dereference, address:
0000000000000010
[  502.715260] #PF: supervisor read access in kernel mode
[  502.715903] #PF: error_code(0x0000) - not-present page
[  502.716546] PGD 103984067 P4D 103984067 PUD 17592b067 PMD 0
[  502.717252] Oops: 0000 [#1] SMP
[  502.720308] RIP: 0010:trace_note.isra.0+0x86/0x360
[  502.732872] Call Trace:
[  502.733193]  __blk_add_trace.cold+0x137/0x1a3
[  502.733734]  blk_add_trace_rq+0x7b/0xd0
[  502.734207]  blk_add_trace_rq_issue+0x54/0xa0
[  502.734755]  blk_mq_start_request+0xde/0x1b0
[  502.735287]  scsi_queue_rq+0x528/0x1140
...
[  502.742704]  sg_new_write.isra.0+0x16e/0x3e0
[  502.747501]  sg_ioctl+0x466/0x1100

Reproduce method:
  ioctl(/dev/sda, BLKTRACESETUP, blk_user_trace_setup[buf_size=127])
  ioctl(/dev/sda, BLKTRACESTART)
  ioctl(/dev/sdb, BLKTRACESETUP, blk_user_trace_setup[buf_size=127])
  ioctl(/dev/sdb, BLKTRACESTART)

  echo 0 > /sys/block/sdb/trace/enable &
  // Add delay(mdelay/msleep) before kernel enters blk_trace_free()

  ioctl$SG_IO(/dev/sda, SG_IO, ...)
  // Enters trace_note_tsk() after blk_trace_free() returned
  // Use mdelay in rcu region rather than msleep(which may schedule out)

Remove blk_trace from running_list before calling blk_trace_free() by
sysfs if blk_trace is at Blktrace_running state.

Fixes: c71a896154119f ("blktrace: add ftrace plugin")
Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Link: https://lore.kernel.org/r/20210923134921.109194-1-chengzhihao1@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-09-30 10:09:24 +02:00
..
blktrace.c
blktrace: Fix uaf in blk_trace access after removing by sysfs
2021-09-30 10:09:24 +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_internal.h
treewide: Rename rcu_dereference_raw_notrace() to _check()
2019-08-01 14:16:21 -07:00
ftrace.c
ftrace: Do not blindly read the ip address in ftrace_bug()
2021-06-16 11:59:45 +02:00
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_benchmark.c
tracing: Use CONFIG_PREEMPTION
2019-07-31 19:03:35 +02:00
ring_buffer.c
tracing: Fix bug in rb_per_cpu_empty() that might cause deadloop.
2021-07-28 13:31:00 +02:00
rpm-traces.c
…
trace_benchmark.c
…
trace_benchmark.h
…
trace_branch.c
x86/uaccess, ftrace: Fix ftrace_likely_update() vs. SMAP
2019-04-03 11:02:24 +02:00
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
tracing/dynevent: Pass extra arguments to match operation
2019-08-31 12:19:38 -04:00
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_filter_test.h
…
trace_events_filter.c
tracing: Avoid memory leak in process_system_preds()
2020-01-09 10:20:00 +01:00
trace_events_hist.c
tracing / histogram: Fix NULL pointer dereference on strcmp() on NULL event name
2021-08-26 08:36:20 -04:00
trace_events_trigger.c
tracing: Fix event trigger to accept redundant spaces
2020-06-30 15:37:10 -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_export.c
…
trace_functions_graph.c
fgraph: Remove redundant ftrace_graph_notrace_addr() test
2019-07-30 21:50:03 -04:00
trace_functions.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
tracing: Silence GCC 9 array bounds warning
2019-05-25 23:04:30 -04:00
trace_kprobe_selftest.c
…
trace_kprobe_selftest.h
…
trace_kprobe.c
tracing/probes: Reject events which have the same name of existing one
2021-09-22 12:26:43 +02:00
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_tmpl.h
tracing/probe: Support user-space dereference
2019-05-25 23:04:42 -04:00
trace_probe.c
tracing/probes: Reject events which have the same name of existing one
2021-09-22 12:26:43 +02:00
trace_probe.h
tracing/probes: Reject events which have the same name of existing one
2021-09-22 12:26:43 +02:00
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_dynamic.c
…
trace_selftest.c
ftrace: Handle tracing when switching between context
2020-11-10 12:37:28 +01:00
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
syscalls: Remove start and number from syscall_get_arguments() args
2019-04-05 09:26:43 -04:00
trace_uprobe.c
tracing/probes: Reject events which have the same name of existing one
2021-09-22 12:26:43 +02:00
trace.c
tracing/histogram: Rename "cpu" to "common_cpu"
2021-07-28 13:31:00 +02:00
trace.h
ftrace: Handle tracing when switching between context
2020-11-10 12:37:28 +01:00
tracing_map.c
tracing: Have the histogram compare functions convert to u64 first
2020-01-09 10:20:00 +01:00
tracing_map.h
…