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Zhihao Cheng dacfd5e4d1 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>
2021-10-06 10:23:40 +02:00
..
blktrace.c
blktrace: Fix uaf in blk_trace access after removing by sysfs
2021-10-06 10:23:40 +02:00
bpf_trace.c
bpf: fix check of allowed specifiers in bpf_trace_printk
2018-12-17 09:38:33 +01:00
ftrace.c
ftrace: Do not blindly read the ip address in ftrace_bug()
2021-06-16 11:36:36 +02:00
Kconfig
Stop the ad-hoc games with -Wno-maybe-initialized
2020-05-20 08:15:37 +02:00
Makefile
Disable the __builtin_return_address() warning globally after all
2016-10-12 10:23:41 -07:00
power-traces.c
cpufreq: schedutil: New governor based on scheduler utilization data
2016-04-02 01:09:12 +02:00
ring_buffer_benchmark.c
…
ring_buffer.c
tracing: Fix bug in rb_per_cpu_empty() that might cause deadloop.
2021-07-28 09:14:28 +02:00
rpm-traces.c
…
trace_benchmark.c
…
trace_benchmark.h
…
trace_branch.c
…
trace_clock.c
tracing: Do no increment trace_clock_global() by one
2021-06-30 08:49:17 -04:00
trace_entries.h
tracing: Set kernel_stack's caller size properly
2020-10-01 20:40:05 +02:00
trace_event_perf.c
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next
2016-05-17 16:26:30 -07:00
trace_events_filter_test.h
…
trace_events_filter.c
tracing: Fix regex_match_front() to not over compare the test string
2018-05-16 10:08:43 +02:00
trace_events_hist.c
tracing: Do not reference char * as a string in histograms
2021-07-20 16:21:11 +02:00
trace_events_trigger.c
tracing: Fix event trigger to accept redundant spaces
2020-06-30 15:38:45 -04:00
trace_events.c
tracing: Do not count ftrace events in top level enable output
2021-02-23 13:59:15 +01:00
trace_export.c
…
trace_functions_graph.c
tracing: Fix missing return symbol in function_graph output
2018-07-11 16:26:43 +02:00
trace_functions.c
ftrace: Have set_ftrace_pid use the bitmap like events do
2016-06-20 09:54:19 -04:00
trace_hwlat.c
tracing/hwlat: Honor the tracing_cpumask
2020-08-26 10:29:03 +02:00
trace_irqsoff.c
tracing: Remove redundant reset per-CPU buff in irqsoff tracer
2016-03-18 16:39:11 -04:00
trace_kdb.c
tracing: Silence GCC 9 array bounds warning
2019-07-10 09:55:28 +02:00
trace_kprobe.c
tracing: Quiet gcc warning about maybe unused link variable
2018-08-03 07:55:12 +02:00
trace_mmiotrace.c
tracing: Expose CPU physical addresses (resource values) for PCI devices
2016-06-20 09:54:22 -04:00
trace_nop.c
tracing: Fix typoes in code comment and printk in trace_nop.c
2016-03-08 11:23:57 -05:00
trace_output.c
tracing: Add NMI tracing in hwlat detector
2016-09-02 12:47:55 -04:00
trace_output.h
…
trace_printk.c
tracing: Handle NULL formats in hold_module_trace_bprintk_format()
2016-06-20 09:46:12 -04:00
trace_probe.c
tracing: probeevent: Fix to support minus offset from symbol
2018-03-28 18:39:23 +02:00
trace_probe.h
tracing: probeevent: Fix to support minus offset from symbol
2018-03-28 18:39:23 +02:00
trace_sched_switch.c
…
trace_sched_wakeup.c
kernel/trace: Fix do not unregister tracepoints when register sched_migrate_task fail
2020-01-14 20:04:26 +01:00
trace_selftest_dynamic.c
…
trace_selftest.c
ftrace: Handle tracing when switching between context
2020-11-10 10:24:02 +01:00
trace_seq.c
…
trace_stack.c
tracing: Have stack tracer compile when MCOUNT_INSN_SIZE is not defined
2020-01-14 20:04:26 +01:00
trace_stat.c
tracing: Fix very unlikely race of registering two stat tracers
2020-02-28 15:42:21 +01:00
trace_stat.h
…
trace_syscalls.c
tracing/syscalls: fix multiline in error message text
2016-09-29 10:25:23 +02:00
trace_uprobe.c
tracing/uprobes: Fix output for multiple string arguments
2019-02-20 10:18:32 +01:00
trace.c
tracing: Do not stop recording comms if the trace file is being read
2021-06-30 08:49:18 -04:00
trace.h
tracing: Fix userstacktrace option for instances
2020-12-11 13:38:01 +01:00
tracing_map.c
tracing: Have the histogram compare functions convert to u64 first
2020-01-12 11:24:14 +01:00
tracing_map.h
tracing: Update some tracing_map constants and comments
2016-04-19 12:16:06 -04:00