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Fri, 26 Jul 2019 12:00:19 -0700 (PDT) From: Arnaldo Carvalho de Melo X-Google-Original-From: Arnaldo Carvalho de Melo Received: by quaco.ghostprotocols.net (Postfix, from userid 1000) id 8561F40340; Fri, 26 Jul 2019 16:00:16 -0300 (-03) Date: Fri, 26 Jul 2019 16:00:16 -0300 To: Vince Weaver Cc: linux-kernel@vger.kernel.org, Peter Zijlstra , Ingo Molnar , Alexander Shishkin , Jiri Olsa , Namhyung Kim Subject: Re: [patch] perf tool divide by zero error if f_header.attr_size==0 Message-ID: <20190726190016.GB20482@kernel.org> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Url: http://acmel.wordpress.com User-Agent: Mutt/1.12.0 (2019-05-25) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Em Tue, Jul 23, 2019 at 11:06:01AM -0400, Vince Weaver escreveu: > 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 I added this on top: diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c index 25f89d0790fe..47877f0f6667 100644 --- a/tools/perf/util/header.c +++ b/tools/perf/util/header.c @@ -3560,6 +3560,9 @@ int perf_session__read_header(struct perf_session *session) } 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; } [acme@quaco perf]$ Thanks, applied. - Arnaldo > > 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); > -- - Arnaldo