tracing: tprobe-events: Reject invalid tracepoint name

JIRA: https://issues.redhat.com/browse/RHEL-86682

commit d045365
Author: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Date:   Wed Feb 26 15:18:54 2025 +0900

    tracing: tprobe-events: Reject invalid tracepoint name

    Commit 57a7e6d ("tracing/fprobe: Support raw tracepoints on
    future loaded modules") allows user to set a tprobe on non-exist
    tracepoint but it does not check the tracepoint name is acceptable.
    So it leads tprobe has a wrong character for events (e.g. with
    subsystem prefix). In this case, the event is not shown in the
    events directory.

    Reject such invalid tracepoint name.

    The tracepoint name must consist of alphabet or digit or '_'.

    Link: https://lore.kernel.org/all/174055073461.4079315.15875502830565214255.stgit@mhiramat.tok.corp.google.com/

    Fixes: 57a7e6d ("tracing/fprobe: Support raw tracepoints on future loaded modules")
    Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
    Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
    Cc: stable@vger.kernel.org

Signed-off-by: Jerome Marchand <jmarchan@redhat.com>

Author: jeromemarchand

kernel/trace/trace_fprobe.c

@@ -1018,6 +1018,19 @@ static int parse_symbol_and_return(int argc, const char *argv[],
 	if (*is_return)
 		return 0;
 
+	if (is_tracepoint) {
+		tmp = *symbol;
+		while (*tmp && (isalnum(*tmp) || *tmp == '_'))
+			tmp++;
+		if (*tmp) {
+			/* find a wrong character. */
+			trace_probe_log_err(tmp - *symbol, BAD_TP_NAME);
+			kfree(*symbol);
+			*symbol = NULL;
+			return -EINVAL;
+		}
+	}
+
 	/* If there is $retval, this should be a return fprobe. */
 	for (i = 2; i < argc; i++) {
 		tmp = strstr(argv[i], "$retval");

kernel/trace/trace_probe.h

@@ -481,6 +481,7 @@ extern int traceprobe_define_arg_fields(struct trace_event_call *event_call,
 	C(NON_UNIQ_SYMBOL,	"The symbol is not unique"),		\
 	C(BAD_RETPROBE,		"Retprobe address must be an function entry"), \
 	C(NO_TRACEPOINT,	"Tracepoint is not found"),		\
+	C(BAD_TP_NAME,		"Invalid character in tracepoint name"),\
 	C(BAD_ADDR_SUFFIX,	"Invalid probed address suffix"), \
 	C(NO_GROUP_NAME,	"Group name is not specified"),		\
 	C(GROUP_TOO_LONG,	"Group name is too long"),		\