rtla: Replace magic number with MAX_PATH

The trace functions use a buffer to manipulate strings that will be
written to tracefs files. These buffers are defined with a magic number
of 1024, which is a common source of vulnerabilities.

Replace the magic number 1024 with the MAX_PATH macro to make the code
safer and more readable. While at it, replace other instances of the
magic number with ARRAY_SIZE() when the buffer is locally defined.

Signed-off-by: Wander Lairson Costa <wander@redhat.com>
Link: https://lore.kernel.org/r/20260309195040.1019085-6-wander@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>

Author: walac

tools/tracing/rtla/src/osnoise.c

@@ -62,7 +62,7 @@ int osnoise_set_cpus(struct osnoise_context *context, char *cpus)
 	if (!context->curr_cpus)
 		return -1;
 
-	snprintf(buffer, 1024, "%s\n", cpus);
+	snprintf(buffer, ARRAY_SIZE(buffer), "%s\n", cpus);
 
 	debug_msg("setting cpus to %s from %s", cpus, context->orig_cpus);
 

tools/tracing/rtla/src/timerlat_u.c

@@ -32,7 +32,7 @@
 static int timerlat_u_main(int cpu, struct timerlat_u_params *params)
 {
 	struct sched_param sp = { .sched_priority = 95 };
-	char buffer[1024];
+	char buffer[MAX_PATH];
 	int timerlat_fd;
 	cpu_set_t set;
 	int retval;
@@ -83,7 +83,7 @@ static int timerlat_u_main(int cpu, struct timerlat_u_params *params)
 
 	/* add should continue with a signal handler */
 	while (true) {
-		retval = read(timerlat_fd, buffer, 1024);
+		retval = read(timerlat_fd, buffer, ARRAY_SIZE(buffer));
 		if (retval < 0)
 			break;
 	}

tools/tracing/rtla/src/trace.c

@@ -313,7 +313,7 @@ void trace_event_add_trigger(struct trace_events *event, char *trigger)
 static void trace_event_disable_filter(struct trace_instance *instance,
 				       struct trace_events *tevent)
 {
-	char filter[1024];
+	char filter[MAX_PATH];
 	int retval;
 
 	if (!tevent->filter)
@@ -325,7 +325,7 @@ static void trace_event_disable_filter(struct trace_instance *instance,
 	debug_msg("Disabling %s:%s filter %s\n", tevent->system,
 		  tevent->event ? : "*", tevent->filter);
 
-	snprintf(filter, 1024, "!%s\n", tevent->filter);
+	snprintf(filter, ARRAY_SIZE(filter), "!%s\n", tevent->filter);
 
 	retval = tracefs_event_file_write(instance->inst, tevent->system,
 					  tevent->event, "filter", filter);
@@ -344,7 +344,7 @@ static void trace_event_save_hist(struct trace_instance *instance,
 {
 	int retval, index, out_fd;
 	mode_t mode = 0644;
-	char path[1024];
+	char path[MAX_PATH];
 	char *hist;
 
 	if (!tevent)
@@ -359,7 +359,7 @@ static void trace_event_save_hist(struct trace_instance *instance,
 	if (retval)
 		return;
 
-	snprintf(path, 1024, "%s_%s_hist.txt", tevent->system, tevent->event);
+	snprintf(path, ARRAY_SIZE(path), "%s_%s_hist.txt", tevent->system, tevent->event);
 
 	printf("  Saving event %s:%s hist to %s\n", tevent->system, tevent->event, path);
 
@@ -391,7 +391,7 @@ static void trace_event_save_hist(struct trace_instance *instance,
 static void trace_event_disable_trigger(struct trace_instance *instance,
 					struct trace_events *tevent)
 {
-	char trigger[1024];
+	char trigger[MAX_PATH];
 	int retval;
 
 	if (!tevent->trigger)
@@ -405,7 +405,7 @@ static void trace_event_disable_trigger(struct trace_instance *instance,
 
 	trace_event_save_hist(instance, tevent);
 
-	snprintf(trigger, 1024, "!%s\n", tevent->trigger);
+	snprintf(trigger, ARRAY_SIZE(trigger), "!%s\n", tevent->trigger);
 
 	retval = tracefs_event_file_write(instance->inst, tevent->system,
 					  tevent->event, "trigger", trigger);
@@ -444,7 +444,7 @@ void trace_events_disable(struct trace_instance *instance,
 static int trace_event_enable_filter(struct trace_instance *instance,
 				     struct trace_events *tevent)
 {
-	char filter[1024];
+	char filter[MAX_PATH];
 	int retval;
 
 	if (!tevent->filter)
@@ -456,7 +456,7 @@ static int trace_event_enable_filter(struct trace_instance *instance,
 		return 1;
 	}
 
-	snprintf(filter, 1024, "%s\n", tevent->filter);
+	snprintf(filter, ARRAY_SIZE(filter), "%s\n", tevent->filter);
 
 	debug_msg("Enabling %s:%s filter %s\n", tevent->system,
 		  tevent->event ? : "*", tevent->filter);
@@ -479,7 +479,7 @@ static int trace_event_enable_filter(struct trace_instance *instance,
 static int trace_event_enable_trigger(struct trace_instance *instance,
 				      struct trace_events *tevent)
 {
-	char trigger[1024];
+	char trigger[MAX_PATH];
 	int retval;
 
 	if (!tevent->trigger)
@@ -491,7 +491,7 @@ static int trace_event_enable_trigger(struct trace_instance *instance,
 		return 1;
 	}
 
-	snprintf(trigger, 1024, "%s\n", tevent->trigger);
+	snprintf(trigger, ARRAY_SIZE(trigger), "%s\n", tevent->trigger);
 
 	debug_msg("Enabling %s:%s trigger %s\n", tevent->system,
 		  tevent->event ? : "*", tevent->trigger);