Call the ASN1_OP_D2I_PRE callback after ASN1_item_ex_new().

In asn1_item_ex_d2i_choice(), only call the ASN1_OP_D2I_PRE callback after
allocation has occurred via ASN1_item_ex_new(). This matches the sequence
handling code and the documentation.

Discussed with tb@

1 files changed, 8 insertions, 10 deletions

diff --git a/src/lib/libcrypto/asn1/tasn_dec.c b/src/lib/libcrypto/asn1/tasn_dec.c
index db4424b6be..48ac38a883 100644
--- a/src/lib/libcrypto/asn1/tasn_dec.c
+++ b/src/lib/libcrypto/asn1/tasn_dec.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: tasn_dec.c,v 1.66 2022/05/12 19:52:31 jsing Exp $ */
+/* $OpenBSD: tasn_dec.c,v 1.67 2022/05/12 20:06:46 jsing Exp $ */
 /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
  * project 2000.
  */
@@ -135,6 +135,9 @@ asn1_item_ex_d2i_choice(ASN1_VALUE **pval, CBS *cbs, const ASN1_ITEM *it,
         ASN1_VALUE **pchptr;
         int i, ret;
 
+        if (aux != NULL)
+                asn1_cb = aux->asn1_cb;
+
         if (it->itype != ASN1_ITYPE_CHOICE)
                 goto err;
 
@@ -152,21 +155,16 @@ asn1_item_ex_d2i_choice(ASN1_VALUE **pval, CBS *cbs, const ASN1_ITEM *it,
                 *pval = NULL;
         }
 
-        if (aux != NULL)
-                asn1_cb = aux->asn1_cb;
+        if (!ASN1_item_ex_new(&achoice, it)) {
+                ASN1error(ERR_R_NESTED_ASN1_ERROR);
+                goto err;
+        }
 
         if (asn1_cb != NULL && !asn1_cb(ASN1_OP_D2I_PRE, &achoice, it, NULL)) {
                 ASN1error(ASN1_R_AUX_ERROR);
                 goto err;
         }
 
-        if (achoice == NULL) {
-                if (!ASN1_item_ex_new(&achoice, it)) {
-                        ASN1error(ERR_R_NESTED_ASN1_ERROR);
-                        goto err;
-                }
-        }
-
         /* Try each possible CHOICE in turn. */
         for (i = 0, tt = it->templates; i < it->tcount; i++, tt++) {
                 pchptr = asn1_get_field_ptr(&achoice, tt);