Port ssl3_get_client_hello to CBS.
Also fix some DTLS cookie bugs. rcvd_cookie is never referenced after being
saved (and the length isn't saved, so it couldn't be used anyway), and the
cookie verification failed to check the length.
For convenience, add a CBS_mem_equal helper function. Saves a bit of
repetition.
Change-Id: I187137733b069f0ac8d8b1bf151eeb80d388b971
Reviewed-on: https://boringssl-review.googlesource.com/1174
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/include/openssl/bytestring.h b/include/openssl/bytestring.h
index 631acdd..544a5d5 100644
--- a/include/openssl/bytestring.h
+++ b/include/openssl/bytestring.h
@@ -73,6 +73,11 @@
* a NUL byte and zero otherwise. */
int CBS_contains_zero_byte(const CBS *cbs);
+/* CBS_mem_equal compares the current contents of |cbs| with the |len| bytes
+ * starting at |data|. If they're equal, it returns one, otherwise zero. If the
+ * lengths match, it uses a constant-time comparison. */
+int CBS_mem_equal(const CBS *cbs, const uint8_t *data, size_t len);
+
/* CBS_get_u8 sets |*out| to the next uint8_t from |cbs| and advances |cbs|. It
* returns one on success and zero on error. */
int CBS_get_u8(CBS *cbs, uint8_t *out);
