linux-kernel - [PATCHv2 5/5] perf tool: Add basic event modifier sanity check

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Date:	Tue, 13 Nov 2012 15:32:58 +0100
From:	Jiri Olsa <jolsa@...hat.com>
To:	Namhyung Kim <namhyung@...nel.org>
Cc:	linux-kernel@...r.kernel.org,
	Corey Ashford <cjashfor@...ux.vnet.ibm.com>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Ingo Molnar <mingo@...e.hu>, Paul Mackerras <paulus@...ba.org>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Arnaldo Carvalho de Melo <acme@...hat.com>
Subject: [PATCHv2 5/5] perf tool: Add basic event modifier sanity check

On Tue, Nov 13, 2012 at 11:22:24AM +0900, Namhyung Kim wrote:
> 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;

ok, v2 attached

thanks,
jirka


---
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.

v2:
  - added length check suggested Namhyung Kim

Signed-off-by: Jiri Olsa <jolsa@...hat.com>
Cc: Corey Ashford <cjashfor@...ux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@...il.com>
Cc: Ingo Molnar <mingo@...e.hu>
Cc: Paul Mackerras <paulus@...ba.org>
Cc: Peter Zijlstra <a.p.zijlstra@...llo.nl>
Cc: Arnaldo Carvalho de Melo <acme@...hat.com>
Cc: Namhyung Kim <namhyung@...nel.org>
---
 tools/perf/util/parse-events.c | 24 ++++++++++++++++++++++++
 tools/perf/util/parse-events.l |  2 +-
 2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index c0b785b..020323a 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -722,6 +722,27 @@ static int get_event_modifier(struct event_modifier *mod, char *str,
 	return 0;
 }
 
+/*
+ * 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;
+
+	/* The sizeof includes 0 byte as well. */
+	if (strlen(str) > (sizeof("ukhGHppp") - 1))
+		return -1;
+
+	while (*p) {
+		if (*p != 'p' && strchr(p + 1, *p))
+			return -1;
+		p++;
+	}
+
+	return 0;
+}
+
 int parse_events__modifier_event(struct list_head *list, char *str, bool add)
 {
 	struct perf_evsel *evsel;
@@ -730,6 +751,9 @@ 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}
 
 %%
-- 
1.7.11.7

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