Add CBS_write_bytes() to copy the remaining CBS bytes to the caller.

This is a common operation when dealing with CBS.

ok miod@ jsing@

2 files changed, 24 insertions, 2 deletions

diff --git a/lib/libssl/src/ssl/bs_cbs.c b/lib/libssl/src/ssl/bs_cbs.c
index 1368fe0fd7f..b36ba489f3a 100644
--- a/lib/libssl/src/ssl/bs_cbs.c
+++ b/lib/libssl/src/ssl/bs_cbs.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: bs_cbs.c,v 1.11 2015/06/17 07:00:22 doug Exp $	*/
+/*	$OpenBSD: bs_cbs.c,v 1.12 2015/06/17 07:06:22 doug Exp $	*/
 /*
  * Copyright (c) 2014, Google Inc.
  *
@@ -96,6 +96,20 @@ CBS_strdup(const CBS *cbs, char **out_ptr)
 }
 
 int
+CBS_write_bytes(const CBS *cbs, uint8_t *dst, size_t dst_len, size_t *copied)
+{
+	if (dst_len < cbs->len)
+		return 0;
+
+	memmove(dst, cbs->data, cbs->len);
+
+	if (copied != NULL)
+		*copied = cbs->len;
+
+	return 1;
+}
+
+int
 CBS_contains_zero_byte(const CBS *cbs)
 {
 	return memchr(cbs->data, 0, cbs->len) != NULL;
diff --git a/lib/libssl/src/ssl/bytestring.h b/lib/libssl/src/ssl/bytestring.h
index 80ca00d77a4..2eb18e207dc 100644
--- a/lib/libssl/src/ssl/bytestring.h
+++ b/lib/libssl/src/ssl/bytestring.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: bytestring.h,v 1.10 2015/06/17 07:00:22 doug Exp $	*/
+/*	$OpenBSD: bytestring.h,v 1.11 2015/06/17 07:06:22 doug Exp $	*/
 /*
  * Copyright (c) 2014, Google Inc.
  *
@@ -92,6 +92,14 @@ int CBS_stow(const CBS *cbs, uint8_t **out_ptr, size_t *out_len);
 int CBS_strdup(const CBS *cbs, char **out_ptr);
 
 /*
+ * CBS_write_bytes writes all of the remaining data from |cbs| into |dst|
+ * if it is at most |dst_len| bytes.  If |copied| is not NULL, it will be set
+ * to the amount copied. It returns one on success and zero otherwise.
+ */
+int CBS_write_bytes(const CBS *cbs, uint8_t *dst, size_t dst_len,
+    size_t *copied);
+
+/*
  * CBS_contains_zero_byte returns one if the current contents of |cbs| contains
  * a NUL byte and zero otherwise.
  */