Commit f006d25a authored by Han Pingtian's avatar Han Pingtian Committed by Arnaldo Carvalho de Melo
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perf tools: Fix buffer overflow error when specifying all tracepoints 



I found when specifying all tracepoints with -e to one of subcommand,
such as 'stat', the program will trigger a buffer overflow error, like
this:

*** buffer overflow detected ***: ./perf terminated
======= Backtrace: =========
/lib64/libc.so.6(__fortify_fail+0x37)[0x382cefb2c7]
....

The tracepoints are separated by comma, something like this:

$ perf stat -a -e `perf list |grep Tracepoint|awk -F'[' '{gsub(/[[:space:]]+/,"",$1);array[FNR]=$1}END{outputs=array[1];for (i=2;i<=FNR;i++){ outputs=outputs "," array[i];};print outputs}'`

The root reason of this problem is that store_event_type() is called for all
events, and will overflow the 'filename' at:

    strncat(filename, orgname, strlen(orgname));

This patch fixes it by calling store_event_type() only when the event name has
been found.

LKML-Reference: <20110106093922.GB6713@hpt.nay.redhat.com>
Signed-off-by: default avatarHan Pingtian <phan@redhat.com>
Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 4b95f135

tools/perf/util/parse-events.c

+30 −31
Original line number Diff line number Diff line
@@ -490,6 +490,31 @@ parse_multiple_tracepoint_event(char *sys_name, const char *evt_exp, 
	return EVT_HANDLED_ALL;

}



static int store_event_type(const char *orgname)

{

	char filename[PATH_MAX], *c;

	FILE *file;

	int id, n;



	sprintf(filename, "%s/", debugfs_path);

	strncat(filename, orgname, strlen(orgname));

	strcat(filename, "/id");



	c = strchr(filename, ':');

	if (c)

		*c = '/';



	file = fopen(filename, "r");

	if (!file)

		return 0;

	n = fscanf(file, "%i", &id);

	fclose(file);

	if (n < 1) {

		pr_err("cannot store event ID\n");

		return -EINVAL;

	}

	return perf_header__push_event(id, orgname);

}



static enum event_result parse_tracepoint_event(const char **strp,

				    struct perf_event_attr *attr)
@@ -533,10 +558,14 @@ static enum event_result parse_tracepoint_event(const char **strp, 
		*strp += strlen(sys_name) + evt_length;

		return parse_multiple_tracepoint_event(sys_name, evt_name,

						       flags);

	} else

	} else {

		if (store_event_type(evt_name) < 0)

			return EVT_FAILED;



		return parse_single_tracepoint_event(sys_name, evt_name,

						     evt_length, attr, strp);

	}

}



static enum event_result

parse_breakpoint_type(const char *type, const char **strp,
@@ -778,41 +807,11 @@ modifier: 
	return ret;

}



static int store_event_type(const char *orgname)

{

	char filename[PATH_MAX], *c;

	FILE *file;

	int id, n;



	sprintf(filename, "%s/", debugfs_path);

	strncat(filename, orgname, strlen(orgname));

	strcat(filename, "/id");



	c = strchr(filename, ':');

	if (c)

		*c = '/';



	file = fopen(filename, "r");

	if (!file)

		return 0;

	n = fscanf(file, "%i", &id);

	fclose(file);

	if (n < 1) {

		pr_err("cannot store event ID\n");

		return -EINVAL;

	}

	return perf_header__push_event(id, orgname);

}



int parse_events(const struct option *opt __used, const char *str, int unset __used)

{

	struct perf_event_attr attr;

	enum event_result ret;



	if (strchr(str, ':'))

		if (store_event_type(str) < 0)

			return -1;



	for (;;) {

		memset(&attr, 0, sizeof(attr));

		ret = parse_event_symbols(&str, &attr);

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