static int ndef_suffix_free(BIO *b, unsigned char **pbuf, int *plen,
void *parg);
+/*
+ * On success, the returned BIO owns the input BIO as part of its BIO chain.
+ * On failure, NULL is returned and the input BIO is owned by the caller.
+ *
+ * Unfortunately cannot constify this due to CMS_stream() and PKCS7_stream()
+ */
BIO *BIO_new_NDEF(BIO *out, ASN1_VALUE *val, const ASN1_ITEM *it)
{
NDEF_SUPPORT *ndef_aux = NULL;
BIO *asn_bio = NULL;
const ASN1_AUX *aux = it->funcs;
ASN1_STREAM_ARG sarg;
+ BIO *pop_bio = NULL;
if (!aux || !aux->asn1_cb) {
ASN1err(ASN1_F_BIO_NEW_NDEF, ASN1_R_STREAMING_NOT_SUPPORTED);
out = BIO_push(asn_bio, out);
if (out == NULL)
goto err;
+ pop_bio = asn_bio;
- BIO_asn1_set_prefix(asn_bio, ndef_prefix, ndef_prefix_free);
- BIO_asn1_set_suffix(asn_bio, ndef_suffix, ndef_suffix_free);
+ if (BIO_asn1_set_prefix(asn_bio, ndef_prefix, ndef_prefix_free) <= 0
+ || BIO_asn1_set_suffix(asn_bio, ndef_suffix, ndef_suffix_free) <= 0
+ || BIO_ctrl(asn_bio, BIO_C_SET_EX_ARG, 0, ndef_aux) <= 0)
+ goto err;
/*
- * Now let callback prepends any digest, cipher etc BIOs ASN1 structure
- * needs.
+ * Now let the callback prepend any digest, cipher, etc., that the BIO's
+ * ASN1 structure needs.
*/
sarg.out = out;
sarg.ndef_bio = NULL;
sarg.boundary = NULL;
- if (aux->asn1_cb(ASN1_OP_STREAM_PRE, &val, it, &sarg) <= 0)
+ /*
+ * The asn1_cb(), must not have mutated asn_bio on error, leaving it in the
+ * middle of some partially built, but not returned BIO chain.
+ */
+ if (aux->asn1_cb(ASN1_OP_STREAM_PRE, &val, it, &sarg) <= 0) {
+ /*
+ * ndef_aux is now owned by asn_bio so we must not free it in the err
+ * clean up block
+ */
+ ndef_aux = NULL;
goto err;
+ }
+
+ /*
+ * We must not fail now because the callback has prepended additional
+ * BIOs to the chain
+ */
ndef_aux->val = val;
ndef_aux->it = it;
ndef_aux->boundary = sarg.boundary;
ndef_aux->out = out;
- BIO_ctrl(asn_bio, BIO_C_SET_EX_ARG, 0, ndef_aux);
-
return sarg.ndef_bio;
err:
+ /* BIO_pop() is NULL safe */
+ (void)BIO_pop(pop_bio);
BIO_free(asn_bio);
OPENSSL_free(ndef_aux);
return NULL;