linux-stable/kernel/trace
Zhihao Cheng d56171d936 blktrace: Fix uaf in blk_trace access after removing by sysfs
[ Upstream commit 5afedf670c ]

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: c71a896154 ("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 15:05:06 +02:00
..
blktrace.c blktrace: Fix uaf in blk_trace access after removing by sysfs 2021-10-06 15:05:06 +02:00
bpf_trace.c bpf: fix check of allowed specifiers in bpf_trace_printk 2018-12-17 09:28:50 +01:00
ftrace.c ftrace: Do not blindly read the ip address in ftrace_bug() 2021-06-16 11:53:05 +02:00
Kconfig Stop the ad-hoc games with -Wno-maybe-initialized 2020-05-20 08:17:10 +02:00
Makefile
power-traces.c
ring_buffer.c tracing: Fix bug in rb_per_cpu_empty() that might cause deadloop. 2021-07-28 11:12:19 +02:00
ring_buffer_benchmark.c
rpm-traces.c
trace.c tracing: Simplify & fix saved_tgids logic 2021-07-20 16:17:47 +02:00
trace.h tracing: Fix userstacktrace option for instances 2020-12-11 13:39:06 +01:00
trace_benchmark.c
trace_benchmark.h
trace_branch.c Revert "x86/uaccess, ftrace: Fix ftrace_likely_update() vs. SMAP" 2019-07-03 13:15:57 +02:00
trace_clock.c tracing: Do no increment trace_clock_global() by one 2021-06-30 08:48:53 -04:00
trace_entries.h tracing: Set kernel_stack's caller size properly 2020-10-01 13:12:32 +02:00
trace_event_perf.c
trace_events.c tracing: Do not count ftrace events in top level enable output 2021-02-23 14:00:31 +01:00
trace_events_filter.c tracing: Fix regex_match_front() to not over compare the test string 2018-05-16 10:10:27 +02:00
trace_events_filter_test.h
trace_events_hist.c tracing: Do not reference char * as a string in histograms 2021-07-20 16:17:48 +02:00
trace_events_trigger.c tracing: Fix event trigger to accept redundant spaces 2020-06-30 15:38:08 -04:00
trace_export.c
trace_functions.c
trace_functions_graph.c tracing/fgraph: Fix set_graph_function from showing interrupts 2019-05-16 19:42:27 +02:00
trace_hwlat.c tracing/hwlat: Honor the tracing_cpumask 2020-08-21 09:48:19 +02:00
trace_irqsoff.c tracing/fgraph: Fix set_graph_function from showing interrupts 2019-05-16 19:42:27 +02:00
trace_kdb.c tracing: Silence GCC 9 array bounds warning 2019-06-25 11:36:50 +08:00
trace_kprobe.c ftrace/kprobe: Show the maxactive number on kprobe_events 2020-04-24 08:00:50 +02:00
trace_mmiotrace.c
trace_nop.c
trace_output.c tracing: Reorder display of TGID to be after PID 2018-07-17 11:39:30 +02:00
trace_output.h
trace_printk.c
trace_probe.c tracing: probeevent: Fix to support minus offset from symbol 2018-03-28 18:24:42 +02:00
trace_probe.h tracing: probeevent: Fix to support minus offset from symbol 2018-03-28 18:24:42 +02:00
trace_sched_switch.c tracing: Fix sched switch start/stop refcount racy updates 2020-02-14 16:32:07 -05:00
trace_sched_wakeup.c kernel/trace: Fix do not unregister tracepoints when register sched_migrate_task fail 2020-01-14 20:05:40 +01:00
trace_selftest.c ftrace: Handle tracing when switching between context 2020-11-10 10:29:04 +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 20:05:40 +01:00
trace_stat.c tracing: Fix very unlikely race of registering two stat tracers 2020-02-28 16:35:58 +01:00
trace_stat.h
trace_syscalls.c
trace_uprobe.c tracing/uprobes: Fix output for multiple string arguments 2019-02-20 10:20:53 +01:00
tracing_map.c tracing: Have the histogram compare functions convert to u64 first 2020-01-09 10:17:56 +01:00
tracing_map.h