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authorAlexei Starovoitov <ast@plumgrid.com>2015-10-22 17:10:14 -0700
committerDavid S. Miller <davem@davemloft.net>2015-10-26 21:49:26 -0700
commit62544ce8e01c1879d420ba309f7f319d24c0f4e6 (patch)
tree394d2f12e6a065b53b3d71bd89ea4b931ce3ec71
parent8b7c94e3478dbb0296293b43a974c3561d01e9fb (diff)
downloadlinux-sh-62544ce8e01c1879d420ba309f7f319d24c0f4e6.tar.gz
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>
-rw-r--r--include/linux/bpf.h1
-rw-r--r--kernel/bpf/arraymap.c25
-rw-r--r--kernel/trace/bpf_trace.c7
3 files changed, 22 insertions, 11 deletions
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index e3a51b74e275..75718fa28260 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -194,7 +194,6 @@ extern const struct bpf_func_proto bpf_map_lookup_elem_proto;
extern const struct bpf_func_proto bpf_map_update_elem_proto;
extern const struct bpf_func_proto bpf_map_delete_elem_proto;
-extern const struct bpf_func_proto bpf_perf_event_read_proto;
extern const struct bpf_func_proto bpf_get_prandom_u32_proto;
extern const struct bpf_func_proto bpf_get_smp_processor_id_proto;
extern const struct bpf_func_proto bpf_tail_call_proto;
diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c
index e3cfe46b074f..3f4c99e06c6b 100644
--- a/kernel/bpf/arraymap.c
+++ b/kernel/bpf/arraymap.c
@@ -292,16 +292,23 @@ static void *perf_event_fd_array_get_ptr(struct bpf_map *map, int fd)
attr = perf_event_attrs(event);
if (IS_ERR(attr))
- return (void *)attr;
+ goto err;
- if (attr->type != PERF_TYPE_RAW &&
- !(attr->type == PERF_TYPE_SOFTWARE &&
- attr->config == PERF_COUNT_SW_BPF_OUTPUT) &&
- attr->type != PERF_TYPE_HARDWARE) {
- perf_event_release_kernel(event);
- return ERR_PTR(-EINVAL);
- }
- return event;
+ if (attr->inherit)
+ goto err;
+
+ if (attr->type == PERF_TYPE_RAW)
+ return event;
+
+ if (attr->type == PERF_TYPE_HARDWARE)
+ return event;
+
+ if (attr->type == PERF_TYPE_SOFTWARE &&
+ attr->config == PERF_COUNT_SW_BPF_OUTPUT)
+ return event;
+err:
+ perf_event_release_kernel(event);
+ return ERR_PTR(-EINVAL);
}
static void perf_event_fd_array_put_ptr(void *ptr)
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,