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From:   Vince Weaver <vincent.weaver@maine.edu>
Date:   Tue, 23 Jul 2019 11:06:01 -0400 (EDT)
To:     linux-kernel@vger.kernel.org
cc:     Arnaldo Carvalho de Melo <acme@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Jiri Olsa <jolsa@redhat.com>,
        Namhyung Kim <namhyung@kernel.org>
Subject: [patch] perf tool divide by zero error if f_header.attr_size==0
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Hello

so I have been having lots of trouble with hand-crafted perf.data files 
causing segfaults and the like, so I have started fuzzing the perf tool.

First issue found:

If f_header.attr_size is 0 in the perf.data file, then perf will crash
with a divide-by-zero error.

Signed-off-by: Vince Weaver <vincent.weaver@maine.edu>

diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index c24db7f4909c..26df60ee9460 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -3559,6 +3559,10 @@ int perf_session__read_header(struct perf_session *session)
 			   data->file.path);
 	}
 
+	if (f_header.attr_size == 0) {
+		return -EINVAL;
+	}
+
 	nr_attrs = f_header.attrs.size / f_header.attr_size;
 	lseek(fd, f_header.attrs.offset, SEEK_SET);