perf sched: Fix memory leaks in __cmd_record detected with -fsanitize=address

An array of strings is passed to cmd_record but not freed. As
cmd_record modifies the array, add another array as a copy that can be
mutated allowing the original array contents to all be freed.

Detected with -fsanitize=address.

Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: https://lore.kernel.org/r/20220824145733.409005-1-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
index 2f6cd1b..a5cf243 100644 (file)
--- a/tools/perf/builtin-sched.c
+++ b/tools/perf/builtin-sched.c
@@ -3355,7 +3355,8 @@ static bool schedstat_events_exposed(void)
 static int __cmd_record(int argc, const char **argv)
 {
        unsigned int rec_argc, i, j;
-       const char **rec_argv;
+       char **rec_argv;
+       const char **rec_argv_copy;
        const char * const record_args[] = {
                "record",
                "-a",
@@ -3384,6 +3385,7 @@ static int __cmd_record(int argc, const char **argv)
                ARRAY_SIZE(schedstat_args) : 0;
 
        struct tep_event *waking_event;
+       int ret;
 
        /*
         * +2 for either "-e", "sched:sched_wakeup" or
@@ -3391,14 +3393,18 @@ static int __cmd_record(int argc, const char **argv)
         */
        rec_argc = ARRAY_SIZE(record_args) + 2 + schedstat_argc + argc - 1;
        rec_argv = calloc(rec_argc + 1, sizeof(char *));
-
        if (rec_argv == NULL)
                return -ENOMEM;
+       rec_argv_copy = calloc(rec_argc + 1, sizeof(char *));
+       if (rec_argv_copy == NULL) {
+               free(rec_argv);
+               return -ENOMEM;
+       }
 
        for (i = 0; i < ARRAY_SIZE(record_args); i++)
                rec_argv[i] = strdup(record_args[i]);
 
-       rec_argv[i++] = "-e";
+       rec_argv[i++] = strdup("-e");
        waking_event = trace_event__tp_format("sched", "sched_waking");
        if (!IS_ERR(waking_event))
                rec_argv[i++] = strdup("sched:sched_waking");
@@ -3409,11 +3415,19 @@ static int __cmd_record(int argc, const char **argv)
                rec_argv[i++] = strdup(schedstat_args[j]);
 
        for (j = 1; j < (unsigned int)argc; j++, i++)
-               rec_argv[i] = argv[j];
+               rec_argv[i] = strdup(argv[j]);
 
        BUG_ON(i != rec_argc);
 
-       return cmd_record(i, rec_argv);
+       memcpy(rec_argv_copy, rec_argv, sizeof(char *) * rec_argc);
+       ret = cmd_record(rec_argc, rec_argv_copy);
+
+       for (i = 0; i < rec_argc; i++)
+               free(rec_argv[i]);
+       free(rec_argv);
+       free(rec_argv_copy);
+
+       return ret;
 }
 
 int cmd_sched(int argc, const char **argv)