tools: suppress ctime() error from static analysers

This function is not thread safe and can be easily misused
even in single threaded scenarios (one such minor bug fixed).

Signed-off-by: Nikos Mavrogiannopoulos <nmav@gnutls.org>

6 files changed, 40 insertions, 13 deletions

diff --git a/src/certtool.c b/src/certtool.c
index 6623b86385..f34f7d4573 100644
--- a/src/certtool.c
+++ b/src/certtool.c
@@ -325,6 +325,7 @@ generate_certificate(gnutls_privkey_t * ret_key,
 	unsigned int usage = 0, server, ask;
 	gnutls_x509_crq_t crq;	/* request */
 	unsigned pk;
+	char timebuf[SIMPLE_CTIME_BUF_SIZE];
 
 	ret = gnutls_x509_crt_init(&crt);
 	if (ret < 0) {
@@ -439,8 +440,8 @@ generate_certificate(gnutls_privkey_t * ret_key,
 
 		if (ca_crt && (secs > gnutls_x509_crt_get_expiration_time(ca_crt))) {
 			time_t exp = gnutls_x509_crt_get_expiration_time(ca_crt);
-			fprintf(stderr, "\nExpiration time: %s", ctime(&secs));
-			fprintf(stderr, "CA expiration time: %s", ctime(&exp));
+			fprintf(stderr, "\nExpiration time: %s\n", simple_ctime(&secs, timebuf));
+			fprintf(stderr, "CA expiration time: %s\n", simple_ctime(&exp, timebuf));
 			fprintf(stderr, "Warning: The time set exceeds the CA's expiration time\n");
 			ask = 1;
 		}
@@ -2652,12 +2653,13 @@ static void print_pkcs7_sig_info(gnutls_pkcs7_signature_info_st *info, common_in
 	gnutls_datum_t data;
 	char prefix[128];
 	int ret;
+	char timebuf[SIMPLE_CTIME_BUF_SIZE];
 
 	print_dn("\tSigner's issuer DN", &info->issuer_dn);
 	print_raw("\tSigner's serial", &info->signer_serial);
 	print_raw("\tSigner's issuer key ID", &info->issuer_keyid);
 	if (info->signing_time != -1)
-		fprintf(outfile, "\tSigning time: %s", ctime(&info->signing_time));
+		fprintf(outfile, "\tSigning time: %s\n", simple_ctime(&info->signing_time, timebuf));
 
 	fprintf(outfile, "\tSignature Algorithm: %s\n", gnutls_sign_get_name(info->algo));
 
diff --git a/src/common.c b/src/common.c
index 664513c9ad..433e31ac90 100644
--- a/src/common.c
+++ b/src/common.c
@@ -1199,3 +1199,22 @@ void log_set(FILE *file)
 {
 	logfile = file;
 }
+
+/* This is very similar to ctime() but it does not force a newline.
+ */
+char *simple_ctime(const time_t *t, char out[SIMPLE_CTIME_BUF_SIZE])
+{
+	struct tm tm;
+
+	if (localtime_r(t, &tm) == NULL)
+		goto error;
+
+	if (!strftime(out, SIMPLE_CTIME_BUF_SIZE, "%c", &tm))
+		goto error;
+
+	return out;
+
+ error:
+	snprintf(out, SIMPLE_CTIME_BUF_SIZE, "[error]");
+	return out;
+}
diff --git a/src/common.h b/src/common.h
index 40f16451ae..884a355a82 100644
--- a/src/common.h
+++ b/src/common.h
@@ -144,4 +144,7 @@ void set_read_funcs(gnutls_session_t session)
 # define set_read_funcs(x)
 #endif
 
+#define SIMPLE_CTIME_BUF_SIZE 64
+char *simple_ctime(const time_t *t, char buf[SIMPLE_CTIME_BUF_SIZE]);
+
 #endif /* GNUTLS_SRC_COMMON_H */
diff --git a/src/ocsptool-common.c b/src/ocsptool-common.c
index dd9dc2dc8d..4286e1484c 100644
--- a/src/ocsptool-common.c
+++ b/src/ocsptool-common.c
@@ -335,6 +335,8 @@ check_ocsp_response(gnutls_x509_crt_t cert,
 	int ret;
 	unsigned int status, cert_status;
 	time_t rtime, vtime, ntime, now;
+	char timebuf1[SIMPLE_CTIME_BUF_SIZE];
+	char timebuf2[SIMPLE_CTIME_BUF_SIZE];
 
 	now = time(0);
 
@@ -395,7 +397,7 @@ check_ocsp_response(gnutls_x509_crt_t cert,
 	}
 
 	if (cert_status == GNUTLS_OCSP_CERT_REVOKED) {
-		printf("*** Certificate was revoked at %s", ctime(&rtime));
+		printf("*** Certificate was revoked at %s\n", simple_ctime(&rtime, timebuf1));
 		ret = 0;
 		goto cleanup;
 	}
@@ -403,17 +405,16 @@ check_ocsp_response(gnutls_x509_crt_t cert,
 	if (ntime == -1) {
 		if (now - vtime > OCSP_VALIDITY_SECS) {
 			printf
-			    ("*** The OCSP response is old (was issued at: %s) ignoring",
-			     ctime(&vtime));
+			    ("*** The OCSP response is old (was issued at: %s) ignoring\n",
+			     simple_ctime(&vtime, timebuf1));
 			ret = -1;
 			goto cleanup;
 		}
 	} else {
 		/* there is a newer OCSP answer, don't trust this one */
 		if (ntime < now) {
-			printf
-			    ("*** The OCSP response was issued at: %s, but there is a newer issue at %s",
-			     ctime(&vtime), ctime(&ntime));
+			printf("*** The OCSP response was issued at: %s but there is a newer issue at %s\n",
+				simple_ctime(&vtime, timebuf1), simple_ctime(&ntime, timebuf2));
 			ret = -1;
 			goto cleanup;
 		}
@@ -445,8 +446,8 @@ check_ocsp_response(gnutls_x509_crt_t cert,
 	}
 
  finish_ok:
-	printf("- OCSP server flags certificate not revoked as of %s",
-	       ctime(&vtime));
+	printf("- OCSP server flags certificate not revoked as of %s\n",
+	       simple_ctime(&vtime, timebuf1));
 	ret = 1;
  cleanup:
 	gnutls_ocsp_resp_deinit(resp);
diff --git a/src/pkcs11.c b/src/pkcs11.c
index bb4acd66ce..d938231c35 100644
--- a/src/pkcs11.c
+++ b/src/pkcs11.c
@@ -281,6 +281,7 @@ pkcs11_list(FILE * outfile, const char *url, int type, unsigned int flags,
 		unsigned int oflags;
 		const char *vendor;
 		char *objurl;
+		char timebuf[SIMPLE_CTIME_BUF_SIZE];
 
 		ret =
 		    gnutls_pkcs11_obj_export_url(crt_list[i], detailed,
@@ -326,7 +327,7 @@ pkcs11_list(FILE * outfile, const char *url, int type, unsigned int flags,
 		}
 
 		if (otype == GNUTLS_PKCS11_OBJ_X509_CRT && exp != -1) {
-			fprintf(outfile, "\tExpires: %s", ctime(&exp));
+			fprintf(outfile, "\tExpires: %s\n", simple_ctime(&exp, timebuf));
 		}
 
 		gnutls_free(output);
diff --git a/src/serv.c b/src/serv.c
index 0866bff903..fbb40258a5 100644
--- a/src/serv.c
+++ b/src/serv.c
@@ -1451,6 +1451,7 @@ static void tcp_server(const char *name, int port)
 				if (accept_fd < 0) {
 					perror("accept()");
 				} else {
+					char timebuf[SIMPLE_CTIME_BUF_SIZE];
 					time_t tt = time(0);
 					char *ctt;
 
@@ -1472,7 +1473,7 @@ static void tcp_server(const char *name, int port)
 					j->close_ok = 0;
 
 					if (verbose != 0) {
-						ctt = ctime(&tt);
+						ctt = simple_ctime(&tt, timebuf);
 						ctt[strlen(ctt) - 1] = 0;
 
 						printf