Fix #12007: RLog heap buffer

Work in progress for #12007.

- Avoid stack-fixed buffer in r_log_vmessage by allocating the formatted message on the heap (r_str_newvf), preventing truncation.
- Add a unit test to ensure long log messages are not truncated.

Author: seifreed

libr/util/log.c

@@ -173,16 +173,20 @@ R_API bool r_log_match(int level, const char *origin) {
 }
 
 R_API void r_log_vmessage(RLogLevel level, const char *origin, const char *func, int line, const char *fmt, va_list ap) {
-	char out[512];
+	char *out;
 	if (!r_log_init ()) {
 		return;
 	}
-	vsnprintf (out, sizeof (out), fmt, ap);
+	out = r_str_newvf (fmt, ap);
+	if (!out) {
+		return;
+	}
 	if (rlog->cbs) {
 		RListIter *iter;
 		RLogCallbackUser *cbu;
 		r_list_foreach (rlog->cbs, iter, cbu) {
 			if (cbu->cb (cbu->user, level, origin, out)) {
+				free (out);
 				return;
 			}
 		}
@@ -221,6 +225,7 @@ R_API void r_log_vmessage(RLogLevel level, const char *origin, const char *func,
 		}
 	}
 	r_strbuf_appendf (sb, "%s %s\n", ts, out);
+	free (out);
 	char *s = r_strbuf_drain (sb);
 	sb = NULL;
 	if (!rlog->quiet) {

test/unit/test_util.c

@@ -229,14 +229,56 @@ bool test_references(void) {
 	mu_end;
 }
 
+typedef struct {
+	const char *expected;
+	size_t expected_len;
+	size_t got_len;
+	bool got_msg;
+	bool match;
+} LogTestCtx;
+
+static bool cb_log_test(void *user, int type, const char *origin, const char *msg) {
+	(void)type;
+	(void)origin;
+	LogTestCtx *ctx = (LogTestCtx *)user;
+	if (!msg) {
+		return true;
+	}
+	ctx->got_len = strlen (msg);
+	ctx->got_msg = true;
+	ctx->match = !strcmp (msg, ctx->expected);
+	return ctx->match;
+}
+
 bool test_log(void) {
 	// Stand up a semi-realistic log environment with an RCore
 	RCore *core = r_core_new ();
+	mu_assert_notnull (core, "r_core_new should not return NULL");
 	r_log_set_quiet (true);
 
 	// https://github.com/radareorg/radare2/issues/22468
 	R_LOG_INFO ("%s", "");
 
+	const size_t slen = 600;
+	char *s = malloc (slen + 1);
+	mu_assert_notnull (s, "malloc should not return NULL");
+	memset (s, 'A', slen);
+	s[slen] = 0;
+	LogTestCtx ctx = {
+		.expected = s,
+		.expected_len = slen,
+		.got_len = 0,
+		.got_msg = false,
+		.match = false,
+	};
+	r_log_add_callback (cb_log_test, &ctx);
+	R_LOG_INFO ("%s", s);
+	r_log_del_callback (cb_log_test);
+	free (s);
+	mu_assert_true (ctx.got_msg, "log callback should receive message");
+	mu_assert_true (ctx.match, "log callback message should match expected string");
+	mu_assert_eq ((int)ctx.got_len, (int)ctx.expected_len, "log message should not be truncated");
+
 	r_core_free (core);
 	mu_end;
 }