X509_NAME_print: NUL-terminate and switch to BIO_printf()

This handles the empty string, which ruby-openssl checks.

Pointed out by anton

1 files changed, 5 insertions, 2 deletions

diff --git a/src/lib/libcrypto/asn1/t_x509.c b/src/lib/libcrypto/asn1/t_x509.c
index 669aec0093..d71e2d2e9a 100644
--- a/src/lib/libcrypto/asn1/t_x509.c
+++ b/src/lib/libcrypto/asn1/t_x509.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: t_x509.c,v 1.48 2025/01/26 20:18:26 tb Exp $ */
+/* $OpenBSD: t_x509.c,v 1.49 2025/01/27 08:05:02 tb Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -549,13 +549,16 @@ X509_NAME_print(BIO *bio, const X509_NAME *name, int obase)
                 started = 1;
         }
 
+        if (!CBB_add_u8(&cbb, '\0'))
+                goto err;
+
         if (!CBB_finish(&cbb, &buf, &buf_len))
                 goto err;
 
         if (buf_len > INT_MAX)
                 goto err;
 
-        if (BIO_write(bio, buf, buf_len) <= 0)
+        if (BIO_printf(bio, "%s", buf) < 0)
                 goto err;
 
         ret = 1;