Re: [PATCH 5/5] perf tool: Add basic event modifier sanity check

From: Namhyung Kim
Date: Mon Nov 12 2012 - 21:22:18 EST


Hi Jiri,

On Mon, 12 Nov 2012 18:34:04 +0100, Jiri Olsa wrote:
> Updating event parser to allow any non zero string containing
> [ukhpGH] characters for event modifier.
>
> The modifier sanity is checked later in parse-event object logic.
> The check validates modifier to contain only one instance of any
> modifier (apart from 'p') present.
[snip]
> +/*
> + * Basic modifier sanity check to validate it contains only one
> + * instance of any modifier (apart from 'p') present.
> + */
> +static int check_modifier(char *str)
> +{
> + char *p = str;
> +
> + while (*p) {
> + if (*p != 'p' && strchr(p + 1, *p))
> + return -1;
> + p++;
> + }

How about adding a length check too? i.e. something like:

if ((p - str) > strlen("ukhGHppp"))
return -1;

Thanks,
Namhyung

> +
> + return 0;
> +}
> +
> int parse_events__modifier_event(struct list_head *list, char *str, bool add)
> {
> struct perf_evsel *evsel;
> @@ -730,6 +747,9 @@ int parse_events__modifier_event(struct list_head *list, char *str, bool add)
> if (str == NULL)
> return 0;
>
> + if (check_modifier(str))
> + return -EINVAL;
> +
> if (!add && get_event_modifier(&mod, str, NULL))
> return -EINVAL;
>
> diff --git a/tools/perf/util/parse-events.l b/tools/perf/util/parse-events.l
> index 66959fa..e9d1134 100644
> --- a/tools/perf/util/parse-events.l
> +++ b/tools/perf/util/parse-events.l
> @@ -82,7 +82,7 @@ num_hex 0x[a-fA-F0-9]+
> num_raw_hex [a-fA-F0-9]+
> name [a-zA-Z_*?][a-zA-Z0-9_*?]*
> name_minus [a-zA-Z_*?][a-zA-Z0-9\-_*?]*
> -modifier_event [ukhpGH]{1,8}
> +modifier_event [ukhpGH]+
> modifier_bp [rwx]{1,3}
>
> %%
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