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Zhihao Cheng 5afedf670c blktrace: Fix uaf in blk_trace access after removing by sysfs 
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>
2021-09-24 11:06:15 -06:00
..
blktrace.c
blktrace: Fix uaf in blk_trace access after removing by sysfs
2021-09-24 11:06:15 -06:00
bpf_trace.c
bpf: Fix bpf-next builds without CONFIG_BPF_EVENTS
2021-08-25 19:41:39 -07:00
bpf_trace.h
…
error_report-traces.c
tracing: add error_report_end trace point
2021-02-26 09:41:02 -08:00
fgraph.c
tracing: Fix various typos in comments
2021-03-23 14:08:18 -04:00
ftrace_internal.h
…
ftrace.c
ftrace: Introduce ftrace_need_init_nop()
2021-08-03 14:31:40 +02:00
Kconfig
tracing: Simplify the Kconfig dependency of FTRACE
2021-08-16 11:37:20 -04:00
kprobe_event_gen_test.c
…
Makefile
tracing: Add a probe that attaches to trace events
2021-08-20 14:18:40 -04:00
power-traces.c
…
preemptirq_delay_test.c
kernel: trace: preemptirq_delay_test: add cpu affinity
2021-02-02 17:02:07 -05:00
ring_buffer_benchmark.c
…
ring_buffer.c
tracing: Replace deprecated CPU-hotplug functions.
2021-08-17 15:47:14 -04:00
rpm-traces.c
…
synth_event_gen_test.c
tracing: Fix various typos in comments
2021-03-23 14:08:18 -04:00
trace_benchmark.c
tracing: Fix some typos in comments
2020-11-10 20:39:40 -05:00
trace_benchmark.h
…
trace_boot.c
bootconfig: Rename xbc_node_find_child() to xbc_node_find_subkey()
2021-09-09 19:14:33 -04:00
trace_branch.c
tracing: Merge irqflags + preempt counter.
2021-02-02 17:02:06 -05:00
trace_clock.c
tracing: Do no increment trace_clock_global() by one
2021-06-18 09:10:00 -04:00
trace_dynevent.c
tracing: Have dynamic events have a ref counter
2021-08-18 18:13:47 -04:00
trace_dynevent.h
tracing: Add DYNAMIC flag for dynamic events
2021-08-18 18:10:32 -04:00
trace_entries.h
trace: Add timerlat tracer
2021-06-25 19:57:24 -04:00
trace_eprobe.c
tracing: Fix some alloc_event_probe() error handling bugs
2021-09-07 20:58:23 -04:00
trace_event_perf.c
tracing: Have dynamic events have a ref counter
2021-08-18 18:13:47 -04:00
trace_events_filter_test.h
…
trace_events_filter.c
tracing: Update create_system_filter() kernel-doc comment
2021-03-25 16:04:35 -04:00
trace_events_hist.c
tracing: Dynamically allocate the per-elt hist_elt_data array
2021-09-08 15:29:16 -04:00
trace_events_inject.c
tracing: Merge irqflags + preempt counter.
2021-02-02 17:02:06 -05:00
trace_events_synth.c
tracing: Have dynamic events have a ref counter
2021-08-18 18:13:47 -04:00
trace_events_trigger.c
tracing: Add a probe that attaches to trace events
2021-08-20 14:18:40 -04:00
trace_events.c
tracing: Add migrate-disabled counter to tracing output.
2021-09-03 19:42:35 -04:00
trace_export.c
tracing: Fix some typos in comments
2020-11-10 20:39:40 -05:00
trace_functions_graph.c
tracing: Fix various typos in comments
2021-03-23 14:08:18 -04:00
trace_functions.c
tracing: Add "func_no_repeats" option for function tracing
2021-04-15 14:50:02 -04:00
trace_hwlat.c
tracing: Replace deprecated CPU-hotplug functions.
2021-08-17 15:47:14 -04:00
trace_irqsoff.c
tracing: Merge irqflags + preempt counter.
2021-02-02 17:02:06 -05:00
trace_kdb.c
kdb: Rename members of struct kdbtab_t
2021-07-27 17:05:06 +01:00
trace_kprobe_selftest.c
…
trace_kprobe_selftest.h
…
trace_kprobe.c
tracing: Add a probe that attaches to trace events
2021-08-20 14:18:40 -04:00
trace_mmiotrace.c
tracing: Remove definition of DEBUG in trace_mmiotrace.c
2021-02-02 17:02:07 -05:00
trace_nop.c
…
trace_osnoise.c
tracing/osnoise: Fix missed cpus_read_unlock() in start_per_cpu_kthreads()
2021-09-08 15:10:24 -04:00
trace_output.c
tracing: Add migrate-disabled counter to tracing output.
2021-09-03 19:42:35 -04:00
trace_output.h
ftrace: Add recording of functions that caused recursion
2020-11-06 08:42:26 -05:00
trace_preemptirq.c
…
trace_printk.c
tracing: Add a verifier to check string pointers for trace events
2021-03-18 12:58:27 -04:00
trace_probe_tmpl.h
tracing/probes: Have process_fetch_insn() take a void * instead of pt_regs
2021-08-19 09:09:03 -04:00
trace_probe.c
tracing: Add a probe that attaches to trace events
2021-08-20 14:18:40 -04:00
trace_probe.h
tracing: Add a probe that attaches to trace events
2021-08-20 14:18:40 -04:00
trace_recursion_record.c
ftrace: Add recording of functions that caused recursion
2020-11-06 08:42:26 -05:00
trace_sched_switch.c
…
trace_sched_wakeup.c
tracing: Change variable type as bool for clean-up
2021-06-30 09:19:14 -04:00
trace_selftest_dynamic.c
…
trace_selftest.c
tracing: Fix various typos in comments
2021-03-23 14:08:18 -04:00
trace_seq.c
tracing: Fix various typos in comments
2021-03-23 14:08:18 -04:00
trace_stack.c
ftrace: Have the callbacks receive a struct ftrace_regs instead of pt_regs
2020-11-13 12:14:55 -05:00
trace_stat.c
…
trace_stat.h
…
trace_synth.h
tracing: synth events: increase max fields count
2021-09-08 15:29:16 -04:00
trace_syscalls.c
tracing: Merge irqflags + preempt counter.
2021-02-02 17:02:06 -05:00
trace_uprobe.c
tracing/probes: Reject events which have the same name of existing one
2021-08-19 09:15:19 -04:00
trace.c
More tracing updates for 5.15:
2021-09-09 13:11:15 -07:00
trace.h
tracing: Add a probe that attaches to trace events
2021-08-20 14:18:40 -04:00
tracing_map.c
tracing: Fix some typos in comments
2020-11-10 20:39:40 -05:00
tracing_map.h
tracing: Fix some typos in comments
2020-11-10 20:39:40 -05:00