tracing/probe: Check event name length correctly

mhiramat · rostedt · commit dec65d79fd26 · 2019-03-14T19:53:47.000-04:00
Ensure given name of event is not too long when parsing it, and fix to update event name offset correctly when the group name is given. For example, this makes probe event to check the "p:foo/" error case correctly. Link: http://lkml.kernel.org/r/155253782046.14922.14724124823730168629.stgit@devnote2 Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
@@ -159,6 +159,7 @@ int traceprobe_parse_event_name(const char **pevent, const char **pgroup,
 				char *buf)
 {
 	const char *slash, *event = *pevent;
+	int len;
 
 	slash = strchr(event, '/');
 	if (slash) {
@@ -173,10 +174,15 @@ int traceprobe_parse_event_name(const char **pevent, const char **pgroup,
 		strlcpy(buf, event, slash - event + 1);
 		*pgroup = buf;
 		*pevent = slash + 1;
+		event = *pevent;
 	}
-	if (strlen(event) == 0) {
+	len = strlen(event);
+	if (len == 0) {
 		pr_info("Event name is not specified\n");
 		return -EINVAL;
+	} else if (len > MAX_EVENT_NAME_LEN) {
+		pr_info("Event name is too long\n");
+		return -E2BIG;
 	}
 	return 0;
 }

Original file line number	Diff line number	Diff line change
`@@ -159,6 +159,7 @@ int traceprobe_parse_event_name(const char pevent, const char pgroup,`
`159`	`159`	`char *buf)`
`160`	`160`	`{`
`161`	`161`	`const char slash, event = *pevent;`
	`162`	`+ int len;`
`162`	`163`
`163`	`164`	`slash = strchr(event, '/');`
`164`	`165`	`if (slash) {`
`@@ -173,10 +174,15 @@ int traceprobe_parse_event_name(const char pevent, const char pgroup,`
`173`	`174`	`strlcpy(buf, event, slash - event + 1);`
`174`	`175`	`*pgroup = buf;`
`175`	`176`	`*pevent = slash + 1;`
	`177`	`+ event = *pevent;`
`176`	`178`	`}`
`177`		`- if (strlen(event) == 0) {`
	`179`	`+ len = strlen(event);`
	`180`	`+ if (len == 0) {`
`178`	`181`	`pr_info("Event name is not specified\n");`
`179`	`182`	`return -EINVAL;`
	`183`	`+ } else if (len > MAX_EVENT_NAME_LEN) {`
	`184`	`+ pr_info("Event name is too long\n");`
	`185`	`+ return -E2BIG;`
`180`	`186`	`}`
`181`	`187`	`return 0;`
`182`	`188`	`}`