1 files changed, 10 insertions, 4 deletions

diff --git a/src/lib/libcrypto/x509/x509_conf.c b/src/lib/libcrypto/x509/x509_conf.c
index 8c4cf5793c..6d611204a5 100644
--- a/src/lib/libcrypto/x509/x509_conf.c
+++ b/src/lib/libcrypto/x509/x509_conf.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: x509_conf.c,v 1.8 2024/06/18 05:24:24 tb Exp $ */
+/* $OpenBSD: x509_conf.c,v 1.9 2024/06/18 05:32:38 tb Exp $ */
 /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
  * project 1999.
  */
@@ -188,7 +188,7 @@ static X509_EXTENSION *
 do_ext_i2d(const X509V3_EXT_METHOD *method, int ext_nid, int crit,
     void *ext_struc)
 {
-        unsigned char *ext_der;
+        unsigned char *ext_der = NULL;
         int ext_len;
         ASN1_OCTET_STRING *ext_oct = NULL;
         X509_EXTENSION *ext;
@@ -201,16 +201,21 @@ do_ext_i2d(const X509V3_EXT_METHOD *method, int ext_nid, int crit,
                         goto merr;
         } else {
                 unsigned char *p;
-                ext_len = method->i2d(ext_struc, NULL);
+
+                if ((ext_len = method->i2d(ext_struc, NULL)) <= 0)
+                        goto merr;
                 if ((ext_der = malloc(ext_len)) == NULL)
                         goto merr;
                 p = ext_der;
-                method->i2d(ext_struc, &p);
+                if (method->i2d(ext_struc, &p) != ext_len)
+                        goto merr;
         }
         if ((ext_oct = ASN1_OCTET_STRING_new()) == NULL)
                 goto merr;
         ext_oct->data = ext_der;
         ext_oct->length = ext_len;
+        ext_der = NULL;
+        ext_len = 0;
 
         ext = X509_EXTENSION_create_by_NID(NULL, ext_nid, crit, ext_oct);
         if (ext == NULL)
@@ -220,6 +225,7 @@ do_ext_i2d(const X509V3_EXT_METHOD *method, int ext_nid, int crit,
         return ext;
 
  merr:
+        free(ext_der);
         ASN1_OCTET_STRING_free(ext_oct);
         X509V3error(ERR_R_MALLOC_FAILURE);
         return NULL;