Require all ASN1_PRIMITIVE_FUNCS functions to be provided.

If an ASN.1 item provides its own ASN1_PRIMITIVE_FUNCS functions, require
all functions to be provided (currently excluding prim_clear). This avoids
situations such as having a custom allocator that returns a specific struct
but then is then printed using the default primative print functions, which
interpret the memory as a different struct.

Found by oss-fuzz, fixes issue #13799.

ok beck@, tb@

1 files changed, 8 insertions, 8 deletions

diff --git a/src/lib/libcrypto/asn1/tasn_fre.c b/src/lib/libcrypto/asn1/tasn_fre.c
index c05310ec28..b621af3b37 100644
--- a/src/lib/libcrypto/asn1/tasn_fre.c
+++ b/src/lib/libcrypto/asn1/tasn_fre.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: tasn_fre.c,v 1.16 2018/04/06 12:16:06 bluhm Exp $ */
+/* $OpenBSD: tasn_fre.c,v 1.17 2019/04/01 15:48:04 jsing Exp $ */
 /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
  * project 2000.
  */
@@ -193,14 +193,14 @@ void
 ASN1_primitive_free(ASN1_VALUE **pval, const ASN1_ITEM *it)
 {
         int utype;
-        if (it) {
-                const ASN1_PRIMITIVE_FUNCS *pf;
-                pf = it->funcs;
-                if (pf && pf->prim_free) {
-                        pf->prim_free(pval, it);
-                        return;
-                }
+
+        if (it != NULL && it->funcs != NULL) {
+                const ASN1_PRIMITIVE_FUNCS *pf = it->funcs;
+
+                pf->prim_free(pval, it);
+                return;
         }
+
         /* Special case: if 'it' is NULL free contents of ASN1_TYPE */
         if (!it) {
                 ASN1_TYPE *typ = (ASN1_TYPE *)*pval;