From 98e1da905cbe64bb023a165c7c01eef5e800609e Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Sat, 21 May 2011 20:08:15 +0200 Subject: [PATCH] perf tools: Robustify dynamic sample content fetch Ensure the size of the dynamic fields such as callchains or raw events don't overlap the whole event boundaries. This prevents from dereferencing junk if the given size of the callchain goes too eager. Reported-by: Linus Torvalds Reported-by: Ingo Molnar Signed-off-by: Frederic Weisbecker Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Arnaldo Carvalho de Melo Cc: Stephane Eranian --- tools/perf/util/evsel.c | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c index bfce8bf642fa..ee0fe0dffa71 100644 --- a/tools/perf/util/evsel.c +++ b/tools/perf/util/evsel.c @@ -303,6 +303,17 @@ static int perf_event__parse_id_sample(const union perf_event *event, u64 type, return 0; } +static bool sample_overlap(const union perf_event *event, + const void *offset, u64 size) +{ + const void *base = event; + + if (offset + size > base + event->header.size) + return true; + + return false; +} + int perf_event__parse_sample(const union perf_event *event, u64 type, int sample_size, bool sample_id_all, struct perf_sample *data) @@ -373,14 +384,29 @@ int perf_event__parse_sample(const union perf_event *event, u64 type, } if (type & PERF_SAMPLE_CALLCHAIN) { + if (sample_overlap(event, array, sizeof(data->callchain->nr))) + return -EFAULT; + data->callchain = (struct ip_callchain *)array; + + if (sample_overlap(event, array, data->callchain->nr)) + return -EFAULT; + array += 1 + data->callchain->nr; } if (type & PERF_SAMPLE_RAW) { u32 *p = (u32 *)array; + + if (sample_overlap(event, array, sizeof(u32))) + return -EFAULT; + data->raw_size = *p; p++; + + if (sample_overlap(event, p, data->raw_size)) + return -EFAULT; + data->raw_data = p; } -- 2.20.1