Convert BER to DER in d2i_PKCS7 if needed

crypto/pkcs7/pkcs7_asn1.c

@@ -5,6 +5,7 @@
 
 #include "internal.h"
 #include "../internal.h"
+#include "../bytestring/internal.h"
 
 ASN1_ADB_TEMPLATE(p7default) = ASN1_EXP_OPT(PKCS7, d.other, ASN1_ANY, 0);
 
@@ -22,7 +23,57 @@ ASN1_SEQUENCE(PKCS7) = {
     ASN1_ADB_OBJECT(PKCS7)
 } ASN1_SEQUENCE_END(PKCS7)
 
-IMPLEMENT_ASN1_FUNCTIONS(PKCS7)
+IMPLEMENT_ASN1_ALLOC_FUNCTIONS(PKCS7)
+
+PKCS7 *d2i_PKCS7(PKCS7 **a, const unsigned char **in, long len) {
+  uint8_t *der_bytes = NULL;
+  PKCS7 *ret = NULL;
+  CBS cbs, cbs_der;
+
+  if (!in) {
+    return NULL;
+  }
+
+  CBS_init(&cbs, *in, len);
+  // |CBS_asn1_ber_to_der| will allocate memory and point |der_bytes| to it.
+  // we're responsible for freeing this below.
+  if (!CBS_asn1_ber_to_der(&cbs, &cbs_der, &der_bytes)) {
+      goto err;
+  }
+
+  // |CBS_asn1_ber_to_der| will set |der_bytes| to NULL if it doesn't detect
+  // any convertible BER elements in |in|.
+  if (der_bytes == NULL) {
+    ret = (PKCS7 *) ASN1_item_d2i(
+        (ASN1_VALUE **) a, in, len,
+        ASN1_ITEM_rptr(PKCS7)
+    );
+  } else {
+    // |ASN1_item_d2i| will increment the input pointer by |der_len| length, so
+    // save off another pointer so we can free |der_bytes| at the end of this
+    // function.
+    uint8_t *der_bytes_ptr = der_bytes;
+    size_t der_len = CBS_len(&cbs_der);
+    ret = (PKCS7 *) ASN1_item_d2i(
+        (ASN1_VALUE **) a, (const uint8_t**) &der_bytes_ptr,
+        der_len, ASN1_ITEM_rptr(PKCS7)
+    );
+    // Advance |*in| by however many bytes |ASN1_item_d2i| advanced
+    // |der_bytes_ptr|
+    *in += der_bytes_ptr - der_bytes;
+  }
+
+err:
+  OPENSSL_free(der_bytes);
+  der_bytes = NULL;
+  return ret;
+}
+
+int i2d_PKCS7(PKCS7 *a, unsigned char **out) {
+    return ASN1_item_i2d((ASN1_VALUE *)a, out, ASN1_ITEM_rptr(PKCS7));
+}
+
+IMPLEMENT_ASN1_DUP_FUNCTION(PKCS7)
 
 ASN1_SEQUENCE(PKCS7_SIGNED) = {
         ASN1_SIMPLE(PKCS7_SIGNED, version, ASN1_INTEGER),