Allow out_present to be NULL in CBS_get_optional_asn1
This is useful to skip an optional element, and mirrors the behaviour of
CBS_get_optional_asn1_octet_string.
Change-Id: Icb538c5e99a1d4e46412cae3c438184a94fab339
Reviewed-on: https://boringssl-review.googlesource.com/5800
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/crypto/bytestring/cbs.c b/crypto/bytestring/cbs.c
index c0fb677..5e0c538 100644
--- a/crypto/bytestring/cbs.c
+++ b/crypto/bytestring/cbs.c
@@ -329,14 +329,19 @@
}
int CBS_get_optional_asn1(CBS *cbs, CBS *out, int *out_present, unsigned tag) {
+ int present = 0;
+
if (CBS_peek_asn1_tag(cbs, tag)) {
if (!CBS_get_asn1(cbs, out, tag)) {
return 0;
}
- *out_present = 1;
- } else {
- *out_present = 0;
+ present = 1;
}
+
+ if (out_present != NULL) {
+ *out_present = present;
+ }
+
return 1;
}
diff --git a/include/openssl/bytestring.h b/include/openssl/bytestring.h
index f6db950..1b1a0a9 100644
--- a/include/openssl/bytestring.h
+++ b/include/openssl/bytestring.h
@@ -178,10 +178,10 @@
* in 64 bits. */
OPENSSL_EXPORT int CBS_get_asn1_uint64(CBS *cbs, uint64_t *out);
-/* CBS_get_optional_asn1 gets an optional explicitly-tagged element
- * from |cbs| tagged with |tag| and sets |*out| to its contents. If
- * present, it sets |*out_present| to one, otherwise zero. It returns
- * one on success, whether or not the element was present, and zero on
+/* CBS_get_optional_asn1 gets an optional explicitly-tagged element from |cbs|
+ * tagged with |tag| and sets |*out| to its contents. If present and if
+ * |out_present| is not NULL, it sets |*out_present| to one, otherwise zero. It
+ * returns one on success, whether or not the element was present, and zero on
* decode failure. */
OPENSSL_EXPORT int CBS_get_optional_asn1(CBS *cbs, CBS *out, int *out_present,
unsigned tag);
