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| author | Song Liu <songliubraving@fb.com> | 2019-05-07 18:15:45 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2019-06-03 11:58:18 +0200 |
| commit | 9fd2e48b9ae17978b2c2a98c055c774d5d90bce8 (patch) | |
| tree | 1a19cedd49c777f1082315f48f6eabadfdf96b44 /kernel | |
| parent | Merge tag 'v5.2-rc3' into perf/core, to pick up fixes (diff) | |
| download | linux-9fd2e48b9ae17978b2c2a98c055c774d5d90bce8.tar.xz linux-9fd2e48b9ae17978b2c2a98c055c774d5d90bce8.zip | |
perf/core: Allow non-privileged uprobe for user processes
Currently, non-privileged user could only use uprobe with
kernel.perf_event_paranoid = -1
However, setting perf_event_paranoid to -1 leaks other users' processes to
non-privileged uprobes.
To introduce proper permission control of uprobes, we are building the
following system:
A daemon with CAP_SYS_ADMIN is in charge to create uprobes via tracefs;
Users asks the daemon to create uprobes;
Then user can attach uprobe only to processes owned by the user.
This patch allows non-privileged user to attach uprobe to processes owned
by the user.
The following example shows how to use uprobe with non-privileged user.
This is based on Brendan's blog post [1]
1. Create uprobe with root:
sudo perf probe -x 'readline%return +0($retval):string'
2. Then non-root user can use the uprobe as:
perf record -vvv -e probe_bash:readline__return -p <pid> sleep 20
perf script
[1] http://www.brendangregg.com/blog/2015-06-28/linux-ftrace-uprobe.html
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <kernel-team@fb.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190507161545.788381-1-songliubraving@fb.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/events/core.c | 4 | ||||
| -rw-r--r-- | kernel/trace/trace_uprobe.c | 2 |
2 files changed, 3 insertions, 3 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c index abbd4b3b96c2..3005c80f621d 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -8532,9 +8532,9 @@ static int perf_tp_event_match(struct perf_event *event, if (event->hw.state & PERF_HES_STOPPED) return 0; /* - * All tracepoints are from kernel-space. + * If exclude_kernel, only trace user-space tracepoints (uprobes) */ - if (event->attr.exclude_kernel) + if (event->attr.exclude_kernel && !user_mode(regs)) return 0; if (!perf_tp_filter_match(event, data)) diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c index eb7e06b54741..0d60d6856de5 100644 --- a/kernel/trace/trace_uprobe.c +++ b/kernel/trace/trace_uprobe.c @@ -1331,7 +1331,7 @@ static inline void init_trace_event_call(struct trace_uprobe *tu, call->event.funcs = &uprobe_funcs; call->class->define_fields = uprobe_event_define_fields; - call->flags = TRACE_EVENT_FL_UPROBE; + call->flags = TRACE_EVENT_FL_UPROBE | TRACE_EVENT_FL_CAP_ANY; call->class->reg = trace_uprobe_register; call->data = tu; } |