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 <vincent.weaver@maine.edu>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/alpine.DEB.2.21.1907231100440.14532@macbook-air
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index 20111f8da5cb10f5acdbb00af4c11be2f6342008..47877f0f66670c2e94ac33ad48945f45b6071a2e 100644 (file)
--- 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);