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SubjectRe: [patch] perf tool divide by zero error if f_header.attr_size==0
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 <vincent.weaver@maine.edu>


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

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