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OpenCloudOS-Kernel/kernel/trace
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Daniel Xu 6fa6d28051 lib/strncpy_from_user.c: Mask out bytes after NUL terminator. 
do_strncpy_from_user() may copy some extra bytes after the NUL
terminator into the destination buffer. This usually does not matter for
normal string operations. However, when BPF programs key BPF maps with
strings, this matters a lot.

A BPF program may read strings from user memory by calling the
bpf_probe_read_user_str() helper which eventually calls
do_strncpy_from_user(). The program can then key a map with the
destination buffer. BPF map keys are fixed-width and string-agnostic,
meaning that map keys are treated as a set of bytes.

The issue is when do_strncpy_from_user() overcopies bytes after the NUL
terminator, it can result in seemingly identical strings occupying
multiple slots in a BPF map. This behavior is subtle and totally
unexpected by the user.

This commit masks out the bytes following the NUL while preserving
long-sized stride in the fast path.

Fixes: 6ae08ae3de ("bpf: Add probe_read_{user, kernel} and probe_read_{user, kernel}_str helpers")
Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/21efc982b3e9f2f7b0379eed642294caaa0c27a7.1605642949.git.dxu@dxuuu.xyz
 		2020-11-19 11:56:16 -08:00
..
Kconfig Tracing updates for 5.8: 2020-06-09 10:06:18 -07:00
Makefile Kbuild updates for v5.9 2020-08-09 14:10:26 -07:00
blktrace.c block: add a bdget_part helper 2020-10-05 10:38:33 -06:00
bpf_trace.c lib/strncpy_from_user.c: Mask out bytes after NUL terminator. 2020-11-19 11:56:16 -08:00
bpf_trace.h bpf: Use dedicated bpf_trace_printk event instead of trace_printk() 2020-07-13 16:55:49 -07:00
fgraph.c fgraph: Convert ret_stack tasklist scanning to rcu 2020-09-21 21:06:02 -04:00
ftrace.c Updates for tracing and bootconfig: 2020-10-15 15:51:28 -07:00
ftrace_internal.h x86/ftrace: Have ftrace trampolines turn read-only at the end of system boot up 2020-05-12 18:24:34 -04:00
kprobe_event_gen_test.c tracing: Add kprobe event command generation test module 2020-01-30 09:46:28 -05:00
power-traces.c
…
preemptirq_delay_test.c tracing: Wait for preempt irq delay thread to execute 2020-05-11 17:00:34 -04:00
ring_buffer.c ring-buffer: Fix recursion protection transitions between interrupt context 2020-11-02 15:58:32 -05:00
ring_buffer_benchmark.c sched,tracing: Convert to sched_set_fifo() 2020-07-29 11:43:53 +02:00
rpm-traces.c
…
synth_event_gen_test.c tracing: Add support for dynamic strings to synthetic events 2020-10-05 19:32:18 -04:00
trace.c tracing: Fix the checking of stackidx in __ftrace_trace_stack 2020-11-02 11:21:40 -05:00
trace.h ftrace: Handle tracing when switching between context 2020-11-02 08:52:18 -05:00
trace_benchmark.c trace: Use pr_warn instead of pr_warning 2019-10-18 15:01:57 +02:00
trace_benchmark.h tracing: Fix SPDX format headers to use C++ style comments 2018-08-16 19:08:06 -04:00
trace_boot.c tracing/boot: Add ftrace.instance.*.alloc_snapshot option 2020-10-15 12:01:13 -04:00
trace_branch.c tracing: Make struct ring_buffer less ambiguous 2020-01-13 13:19:38 -05:00
trace_clock.c tracing: Add SPDX License format tags to tracing files 2018-08-16 19:08:06 -04:00
trace_dynevent.c tracing: Delete repeated words in comments 2020-09-21 21:06:02 -04:00
trace_dynevent.h tracing: Remove check_arg() callbacks from dynevent args 2020-02-01 13:09:23 -05:00
trace_entries.h tracing: Make ftrace packed events have align of 1 2020-06-16 21:21:02 -04:00
trace_event_perf.c Merge branch 'perf/urgent' into perf/core, to pick up fixes 2019-10-28 12:38:26 +01:00
trace_events.c Tracing: Fix mismatch section of adding early trace events 2020-10-16 14:56:52 -07:00
trace_events_filter.c treewide: Use fallthrough pseudo-keyword 2020-08-23 17:36:59 -05:00
trace_events_filter_test.h tracing: Fix SPDX format headers to use C++ style comments 2018-08-16 19:08:06 -04:00
trace_events_hist.c tracing: Check return value of __create_val_fields() before using its result 2020-10-15 12:00:59 -04:00
trace_events_inject.c tracing: Initialize val to zero in parse_entry of inject code 2020-01-02 19:04:57 -05:00
trace_events_synth.c tracing: Make -ENOMEM the default error for parse_synth_field() 2020-11-02 15:58:32 -05:00
trace_events_trigger.c tracing: Fix event trigger to accept redundant spaces 2020-06-23 21:51:40 -04:00
trace_export.c treewide: Convert macro and uses of __section(foo) to __section("foo") 2020-10-25 14:51:49 -07:00
trace_functions.c tracing: Enable creating new instance early boot 2020-09-21 21:06:04 -04:00
trace_functions_graph.c tracing: make tracing_init_dentry() returns an integer instead of a d_entry pointer 2020-09-18 22:17:14 -04:00
trace_hwlat.c tracing: make tracing_init_dentry() returns an integer instead of a d_entry pointer 2020-09-18 22:17:14 -04:00
trace_irqsoff.c tracing: Rename trace_buffer to array_buffer 2020-01-13 13:19:38 -05:00
trace_kdb.c tracing: Rename trace_buffer to array_buffer 2020-01-13 13:19:38 -05:00
trace_kprobe.c kprobes: Use module_name() macro 2020-09-24 15:55:49 +02:00
trace_kprobe_selftest.c selftest/ftrace: Move kprobe selftest function to separate compile unit 2018-07-30 18:41:04 -04:00
trace_kprobe_selftest.h tracing: Fix SPDX format headers to use C++ style comments 2018-08-16 19:08:06 -04:00
trace_mmiotrace.c tracing: Make struct ring_buffer less ambiguous 2020-01-13 13:19:38 -05:00
trace_nop.c
…
trace_output.c tracing: Make the space reserved for the pid wider 2020-09-18 12:42:11 -04:00
trace_output.h tracing: Fix SPDX format headers to use C++ style comments 2018-08-16 19:08:06 -04:00
trace_preemptirq.c lockdep: fix order in trace_hardirqs_off_caller() 2020-09-14 10:08:07 +02:00
trace_printk.c Updates for tracing and bootconfig: 2020-10-15 15:51:28 -07:00
trace_probe.c tracing/probe: Fix memleak in fetch_op_data operations 2020-06-16 21:21:02 -04:00
trace_probe.h tracing: Move is_good_name() from trace_probe.h to trace.h 2020-10-15 12:01:13 -04:00
trace_probe_tmpl.h tracing/probe: Support user-space dereference 2019-05-25 23:04:42 -04:00
trace_sched_switch.c tracing: Fix sched switch start/stop refcount racy updates 2020-01-30 09:46:10 -05:00
trace_sched_wakeup.c tracing: Make struct ring_buffer less ambiguous 2020-01-13 13:19:38 -05:00
trace_selftest.c ftrace: Handle tracing when switching between context 2020-11-02 08:52:18 -05:00
trace_selftest_dynamic.c
…
trace_seq.c tracing: Remove unused TRACE_SEQ_BUF_USED 2020-01-21 18:39:54 -05:00
trace_stack.c tracing: make tracing_init_dentry() returns an integer instead of a d_entry pointer 2020-09-18 22:17:14 -04:00
trace_stat.c tracing: make tracing_init_dentry() returns an integer instead of a d_entry pointer 2020-09-18 22:17:14 -04:00
trace_stat.h tracing: Use generic type for comparator function 2019-11-14 13:15:11 -05:00
trace_synth.h tracing: Add support for dynamic strings to synthetic events 2020-10-05 19:32:18 -04:00
trace_syscalls.c Tracing updates: 2020-02-06 07:12:11 +00:00
trace_uprobe.c tracing/uprobes: Support perf-style return probe 2020-09-21 21:06:03 -04:00
tracing_map.c tracing: Delete repeated words in comments 2020-09-21 21:06:02 -04:00
tracing_map.h tracing: Fix SPDX format headers to use C++ style comments 2018-08-16 19:08:06 -04:00