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SubjectRe: [PATCH v2] tools/perf/util: null-terminate version char array upon error
Em Tue, May 14, 2019 at 07:01:00AM -0400, Donald Yandt escreveu:
> If fgets fails due to any other error besides end-of-file, the version char array may not even be null-terminated.

Thanks, but out of curiosity, was this found just by visual inspection?
Some static analysis tool? An actual problem you stumbled when
processing some /proc/version in a custom kernel?

Also please consider adding a:

Fixes: a1645ce12adb ("perf: 'perf kvm' tool for monitoring guest performance from host")

So that we can get this picked up by the stable kernel trees. I'm adding
it now.

Thanks!

- Arnaldo

> Signed-off-by: Donald Yandt <donald.yandt@gmail.com>
> ---
> tools/perf/util/machine.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
> index 3c520baa1..28a9541c4 100644
> --- a/tools/perf/util/machine.c
> +++ b/tools/perf/util/machine.c
> @@ -1234,8 +1234,9 @@ static char *get_kernel_version(const char *root_dir)
> if (!file)
> return NULL;
>
> - version[0] = '\0';
> tmp = fgets(version, sizeof(version), file);
> + if (!tmp)
> + *version = '\0';
> fclose(file);
>
> name = strstr(version, prefix);
> --
> 2.20.1

--

- Arnaldo

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