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: 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>		2021-09-24 11:06:15 -06:00
..
Kconfig	tracing: Simplify the Kconfig dependency of FTRACE	2021-08-16 11:37:20 -04:00
Makefile	tracing: Add a probe that attaches to trace events	2021-08-20 14:18:40 -04:00
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	…
fgraph.c	…
ftrace.c	ftrace: Introduce ftrace_need_init_nop()	2021-08-03 14:31:40 +02:00
ftrace_internal.h	…
kprobe_event_gen_test.c	…
power-traces.c	…
preemptirq_delay_test.c	…
ring_buffer.c	tracing: Replace deprecated CPU-hotplug functions.	2021-08-17 15:47:14 -04:00
ring_buffer_benchmark.c	…
rpm-traces.c	…
synth_event_gen_test.c	…
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
trace_benchmark.c	…
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	…
trace_clock.c	…
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_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.c	tracing: Add migrate-disabled counter to tracing output.	2021-09-03 19:42:35 -04:00
trace_events_filter.c	…
trace_events_filter_test.h	…
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	…
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_export.c	…
trace_functions.c	…
trace_functions_graph.c	…
trace_hwlat.c	tracing: Replace deprecated CPU-hotplug functions.	2021-08-17 15:47:14 -04:00
trace_irqsoff.c	…
trace_kdb.c	kdb: Rename members of struct kdbtab_t	2021-07-27 17:05:06 +01:00
trace_kprobe.c	tracing: Add a probe that attaches to trace events	2021-08-20 14:18:40 -04:00
trace_kprobe_selftest.c	…
trace_kprobe_selftest.h	…
trace_mmiotrace.c	…
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	…
trace_preemptirq.c	…
trace_printk.c	…
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_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_recursion_record.c	…
trace_sched_switch.c	…
trace_sched_wakeup.c	…
trace_selftest.c	…
trace_selftest_dynamic.c	…
trace_seq.c	…
trace_stack.c	…
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	…
trace_uprobe.c	tracing/probes: Reject events which have the same name of existing one	2021-08-19 09:15:19 -04:00
tracing_map.c	…
tracing_map.h	…