From 7622236ceb167aa3857395f9bdaf871442aa467e Mon Sep 17 00:00:00 2001 From: Vince Weaver Date: Tue, 23 Jul 2019 11:06:01 -0400 Subject: [PATCH] perf header: Fix divide by zero error if f_header.attr_size==0 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. Committer note: Added a pr_err() to tell the user why the command failed. Signed-off-by: Vince Weaver Cc: Alexander Shishkin Cc: Jiri Olsa Cc: Namhyung Kim Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/alpine.DEB.2.21.1907231100440.14532@macbook-air Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/header.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c index 20111f8da5cb..47877f0f6667 100644 --- a/tools/perf/util/header.c +++ b/tools/perf/util/header.c @@ -3559,6 +3559,13 @@ int perf_session__read_header(struct perf_session *session) data->file.path); } + if (f_header.attr_size == 0) { + pr_err("ERROR: The %s file's attr size field is 0 which is unexpected.\n" + "Was the 'perf record' command properly terminated?\n", + data->file.path); + return -EINVAL; + } + nr_attrs = f_header.attrs.size / f_header.attr_size; lseek(fd, f_header.attrs.offset, SEEK_SET); -- 2.30.2