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SubjectRe: [patch] perf tool buffer overflow in perf_header__read_build_ids
Em Tue, Jul 23, 2019 at 04:42:30PM -0400, Vince Weaver escreveu:
> Hello
>
> my perf_tool_fuzzer has found another issue, this one a buffer overflow
> in perf_header__read_build_ids. The build id filename is read in with a
> filename length read from the perf.data file, but this can be longer than
> PATH_MAX which will smash the stack.
>
> This might not be the right fix, not sure if filename should be NUL
> terminated or not.
>
> Signed-off-by: Vince Weaver <vincent.weaver@maine.edu>
>
> diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
> index c24db7f4909c..9a893a26e678 100644
> --- a/tools/perf/util/header.c
> +++ b/tools/perf/util/header.c
> @@ -2001,6 +2001,9 @@ static int perf_header__read_build_ids(struct perf_header *header,
> perf_event_header__bswap(&bev.header);
>
> len = bev.header.size - sizeof(bev);
> +
> + if (len>PATH_MAX) len=PATH_MAX;
> +

Humm, I wonder if we shouldn't just declare the whole file invalid like
you did with the previous patch?

- Arnaldo

> if (readn(input, filename, len) != len)
> goto out;
> /*

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