Fix various malloc failure checks.

asn1_template_noexp_d2i call ASN1_item_ex_free(&skfield,...) on error.

Reworked error handling in asn1_item_ex_combine_new:
- call ASN1_item_ex_free and return the correct error code if
  ASN1_template_new failed.
- dont call ASN1_item_ex_free if ASN1_OP_NEW_PRE failed.

Reworked error handing in x509_name_ex_d2i and x509_name_encode.

(Imported from upstream's 748cb9a17f4f2b77aad816cf658cd4025dc847ee.)

I believe the tasn1_new.c change is a no-op since we have no
ASN1_OP_NEW_PRE hooks anymore. I'm not sure what the commit message is
referring to with ASN1_template_new. It also seems odd as
ASN1_item_ex_free should probably be able to survive *pval being NULL.
Whatever.

We'd previously tried to fix x509_name_ex_d2i, but I think ours wasn't
quite right. (This thing is a mess...) I've aligned that function with
upstream.

Change-Id: Ie71521cd8a1ec357876caadd13be1ce247110f76
Reviewed-on: https://boringssl-review.googlesource.com/13831
Reviewed-by: David Benjamin <davidben@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>

crypto/asn1/tasn_dec.c

@@ -667,6 +667,7 @@ static int asn1_template_noexp_d2i(ASN1_VALUE **val,
             }
             len -= p - q;
             if (!sk_ASN1_VALUE_push((STACK_OF(ASN1_VALUE) *)*val, skfield)) {
+                ASN1_item_ex_free(&skfield, ASN1_ITEM_ptr(tt->item));
                 OPENSSL_PUT_ERROR(ASN1, ERR_R_MALLOC_FAILURE);
                 goto err;
             }

crypto/asn1/tasn_new.c

@@ -160,7 +160,7 @@ static int asn1_item_ex_combine_new(ASN1_VALUE **pval, const ASN1_ITEM *it,
         }
         asn1_set_choice_selector(pval, -1, it);
         if (asn1_cb && !asn1_cb(ASN1_OP_NEW_POST, pval, it, NULL))
-            goto auxerr;
+            goto auxerr2;
         break;
 
     case ASN1_ITYPE_NDEF_SEQUENCE:
@@ -188,10 +188,10 @@ static int asn1_item_ex_combine_new(ASN1_VALUE **pval, const ASN1_ITEM *it,
         for (i = 0, tt = it->templates; i < it->tcount; tt++, i++) {
             pseqval = asn1_get_field_ptr(pval, tt);
             if (!ASN1_template_new(pseqval, tt))
-                goto memerr;
+                goto memerr2;
         }
         if (asn1_cb && !asn1_cb(ASN1_OP_NEW_POST, pval, it, NULL))
-            goto auxerr;
+            goto auxerr2;
         break;
     }
 #ifdef CRYPTO_MDEBUG
@@ -200,18 +200,20 @@ static int asn1_item_ex_combine_new(ASN1_VALUE **pval, const ASN1_ITEM *it,
 #endif
     return 1;
 
+ memerr2:
+    ASN1_item_ex_free(pval, it);
  memerr:
     OPENSSL_PUT_ERROR(ASN1, ERR_R_MALLOC_FAILURE);
-    ASN1_item_ex_free(pval, it);
 #ifdef CRYPTO_MDEBUG
     if (it->sname)
         CRYPTO_pop_info();
 #endif
     return 0;
 
+ auxerr2:
+    ASN1_item_ex_free(pval, it);
  auxerr:
     OPENSSL_PUT_ERROR(ASN1, ASN1_R_AUX_ERROR);
-    ASN1_item_ex_free(pval, it);
 #ifdef CRYPTO_MDEBUG
     if (it->sname)
         CRYPTO_pop_info();

crypto/x509/x_name.c

@@ -229,12 +229,11 @@ static int x509_name_ex_d2i(ASN1_VALUE **val,
 
     if (*val)
         x509_name_ex_free(val, NULL);
+    if (!x509_name_ex_new(&nm.a, NULL))
+        goto err;
     /* We've decoded it: now cache encoding */
-    if (!x509_name_ex_new(&nm.a, NULL) || !BUF_MEM_grow(nm.x->bytes, p - q)) {
-        sk_STACK_OF_X509_NAME_ENTRY_pop_free(intname.s,
-                                             local_sk_X509_NAME_ENTRY_pop_free);
+    if (!BUF_MEM_grow(nm.x->bytes, p - q))
         goto err;
-    }
     OPENSSL_memcpy(nm.x->bytes->data, q, p - q);
 
     /* Convert internal representation to X509_NAME structure */
@@ -245,13 +244,14 @@ static int x509_name_ex_d2i(ASN1_VALUE **val,
             entry->set = i;
             if (!sk_X509_NAME_ENTRY_push(nm.x->entries, entry))
                 goto err;
+            sk_X509_NAME_ENTRY_set(entries, j, NULL);
         }
-        sk_X509_NAME_ENTRY_free(entries);
     }
-    sk_STACK_OF_X509_NAME_ENTRY_free(intname.s);
     ret = x509_name_canon(nm.x);
     if (!ret)
         goto err;
+    sk_STACK_OF_X509_NAME_ENTRY_pop_free(intname.s,
+                                         local_sk_X509_NAME_ENTRY_free);
     nm.x->modified = 0;
     *val = nm.a;
     *in = p;
@@ -259,6 +259,8 @@ static int x509_name_ex_d2i(ASN1_VALUE **val,
  err:
     if (nm.x != NULL)
         X509_NAME_free(nm.x);
+    sk_STACK_OF_X509_NAME_ENTRY_pop_free(intname.s,
+                                         local_sk_X509_NAME_ENTRY_pop_free);
     OPENSSL_PUT_ERROR(X509, ERR_R_ASN1_LIB);
     return 0;
 }
@@ -307,8 +309,10 @@ static int x509_name_encode(X509_NAME *a)
             entries = sk_X509_NAME_ENTRY_new_null();
             if (!entries)
                 goto memerr;
-            if (!sk_STACK_OF_X509_NAME_ENTRY_push(intname.s, entries))
+            if (!sk_STACK_OF_X509_NAME_ENTRY_push(intname.s, entries)) {
+                sk_X509_NAME_ENTRY_free(entries);
                 goto memerr;
+            }
             set = entry->set;
         }
         if (!sk_X509_NAME_ENTRY_push(entries, entry))