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| author | Alexei Starovoitov <ast@plumgrid.com> | 2015-10-22 17:10:14 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2015-10-26 21:49:26 -0700 |
| commit | 62544ce8e01c1879d420ba309f7f319d24c0f4e6 (patch) | |
| tree | 394d2f12e6a065b53b3d71bd89ea4b931ce3ec71 /kernel/trace | |
| parent | 8b7c94e3478dbb0296293b43a974c3561d01e9fb (diff) | |
| download | linux-62544ce8e01c1879d420ba309f7f319d24c0f4e6.tar.bz2 | |
bpf: fix bpf_perf_event_read() helper
Fix safety checks for bpf_perf_event_read():
- only non-inherited events can be added to perf_event_array map
(do this check statically at map insertion time)
- dynamically check that event is local and !pmu->count
Otherwise buggy bpf program can cause kernel splat.
Also fix error path after perf_event_attrs()
and remove redundant 'extern'.
Fixes: 35578d798400 ("bpf: Implement function bpf_perf_event_read() that get the selected hardware PMU conuter")
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Tested-by: Wang Nan <wangnan0@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'kernel/trace')
| -rw-r--r-- | kernel/trace/bpf_trace.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 47febbe7998e..003df3887287 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -199,6 +199,11 @@ static u64 bpf_perf_event_read(u64 r1, u64 index, u64 r3, u64 r4, u64 r5) if (!event) return -ENOENT; + /* make sure event is local and doesn't have pmu::count */ + if (event->oncpu != smp_processor_id() || + event->pmu->count) + return -EINVAL; + /* * we don't know if the function is run successfully by the * return value. It can be judged in other places, such as @@ -207,7 +212,7 @@ static u64 bpf_perf_event_read(u64 r1, u64 index, u64 r3, u64 r4, u64 r5) return perf_event_read_local(event); } -const struct bpf_func_proto bpf_perf_event_read_proto = { +static const struct bpf_func_proto bpf_perf_event_read_proto = { .func = bpf_perf_event_read, .gpl_only = false, .ret_type = RET_INTEGER, |