perf tools: Pre-check sample size before parsing
Frederic Weisbecker [Sat, 21 May 2011 17:33:04 +0000 (19:33 +0200)]
Check that the total size of the sample fields having a fixed
size do not exceed the one of the whole event. This robustifies
the sample parsing.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Stephane Eranian <eranian@google.com>

tools/perf/builtin-test.c
tools/perf/util/event.c
tools/perf/util/event.h
tools/perf/util/evsel.c
tools/perf/util/python.c
tools/perf/util/session.c
tools/perf/util/session.h

index 11e3c84..44d7df2 100644 (file)
@@ -474,6 +474,7 @@ static int test__basic_mmap(void)
        unsigned int nr_events[nsyscalls],
                     expected_nr_events[nsyscalls], i, j;
        struct perf_evsel *evsels[nsyscalls], *evsel;
+       int sample_size = perf_sample_size(attr.sample_type);
 
        for (i = 0; i < nsyscalls; ++i) {
                char name[64];
@@ -558,7 +559,8 @@ static int test__basic_mmap(void)
                        goto out_munmap;
                }
 
-               perf_event__parse_sample(event, attr.sample_type, false, &sample);
+               perf_event__parse_sample(event, attr.sample_type, sample_size,
+                                        false, &sample);
                evsel = perf_evlist__id2evsel(evlist, sample.id);
                if (evsel == NULL) {
                        pr_debug("event with id %" PRIu64
index 1023f67..17c1c3c 100644 (file)
@@ -35,6 +35,22 @@ const char *perf_event__name(unsigned int id)
        return perf_event__names[id];
 }
 
+int perf_sample_size(u64 sample_type)
+{
+       u64 mask = sample_type & PERF_SAMPLE_MASK;
+       int size = 0;
+       int i;
+
+       for (i = 0; i < 64; i++) {
+               if ((mask << i) & 1)
+                       size++;
+       }
+
+       size *= sizeof(u64);
+
+       return size;
+}
+
 static struct perf_sample synth_sample = {
        .pid       = -1,
        .tid       = -1,
index 9c35170..c083328 100644 (file)
@@ -56,6 +56,13 @@ struct read_event {
        u64 id;
 };
 
+
+#define PERF_SAMPLE_MASK                               \
+       (PERF_SAMPLE_IP | PERF_SAMPLE_TID |             \
+        PERF_SAMPLE_TIME | PERF_SAMPLE_ADDR |          \
+       PERF_SAMPLE_ID | PERF_SAMPLE_STREAM_ID |        \
+        PERF_SAMPLE_CPU | PERF_SAMPLE_PERIOD)
+
 struct sample_event {
        struct perf_event_header        header;
        u64 array[];
@@ -75,6 +82,8 @@ struct perf_sample {
        struct ip_callchain *callchain;
 };
 
+int perf_sample_size(u64 sample_type);
+
 #define BUILD_ID_SIZE 20
 
 struct build_id_event {
@@ -178,6 +187,7 @@ int perf_event__preprocess_sample(const union perf_event *self,
 const char *perf_event__name(unsigned int id);
 
 int perf_event__parse_sample(const union perf_event *event, u64 type,
-                            bool sample_id_all, struct perf_sample *sample);
+                            int sample_size, bool sample_id_all,
+                            struct perf_sample *sample);
 
 #endif /* __PERF_RECORD_H */
index d6fd59b..bfce8bf 100644 (file)
@@ -304,7 +304,8 @@ static int perf_event__parse_id_sample(const union perf_event *event, u64 type,
 }
 
 int perf_event__parse_sample(const union perf_event *event, u64 type,
-                            bool sample_id_all, struct perf_sample *data)
+                            int sample_size, bool sample_id_all,
+                            struct perf_sample *data)
 {
        const u64 *array;
 
@@ -319,6 +320,9 @@ int perf_event__parse_sample(const union perf_event *event, u64 type,
 
        array = event->sample.array;
 
+       if (sample_size + sizeof(event->header) > event->header.size)
+               return -EFAULT;
+
        if (type & PERF_SAMPLE_IP) {
                data->ip = event->ip.ip;
                array++;
index 8b0eff8..4174c09 100644 (file)
@@ -690,8 +690,9 @@ static PyObject *pyrf_evlist__read_on_cpu(struct pyrf_evlist *pevlist,
                        return PyErr_NoMemory();
 
                first = list_entry(evlist->entries.next, struct perf_evsel, node);
-               perf_event__parse_sample(event, first->attr.sample_type, sample_id_all,
-                                        &pevent->sample);
+               perf_event__parse_sample(event, first->attr.sample_type,
+                                        perf_sample_size(first->attr.sample_type),
+                                        sample_id_all, &pevent->sample);
                return pyevent;
        }
 
index db65206..8940fd8 100644 (file)
@@ -97,6 +97,7 @@ out:
 void perf_session__update_sample_type(struct perf_session *self)
 {
        self->sample_type = perf_evlist__sample_type(self->evlist);
+       self->sample_size = perf_sample_size(self->sample_type);
        self->sample_id_all = perf_evlist__sample_id_all(self->evlist);
        perf_session__id_header_size(self);
 }
index 8daaa2d..66d4e14 100644 (file)
@@ -43,6 +43,7 @@ struct perf_session {
         */
        struct hists            hists;
        u64                     sample_type;
+       int                     sample_size;
        int                     fd;
        bool                    fd_pipe;
        bool                    repipe;
@@ -159,6 +160,7 @@ static inline int perf_session__parse_sample(struct perf_session *session,
                                             struct perf_sample *sample)
 {
        return perf_event__parse_sample(event, session->sample_type,
+                                       session->sample_size,
                                        session->sample_id_all, sample);
 }