Re: [patch] perf tool divide by zero error if f_header.attr_size==0

[Arnaldo Carvalho de Melo]

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.

Thanks for the patch, will be in my next perf/urgent pull req.

- Arnaldo
 
> Signed-off-by: Vince Weaver <vincent.weaver@xxxxxxxxx>
> 
> 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);