Provide CBS_get_u64().

This will be used in the libcrypto certificate transparency code.

ok tb@

2 files changed, 25 insertions, 2 deletions

diff --git a/src/lib/libssl/bs_cbs.c b/src/lib/libssl/bs_cbs.c
index 627c609bb9..97b0163f3f 100644
--- a/src/lib/libssl/bs_cbs.c
+++ b/src/lib/libssl/bs_cbs.c
@@ -1,4 +1,4 @@
-/*      $OpenBSD: bs_cbs.c,v 1.22 2021/12/15 17:23:34 jsing Exp $       */
+/*      $OpenBSD: bs_cbs.c,v 1.23 2021/12/15 17:30:20 jsing Exp $       */
 /*
  * Copyright (c) 2014, Google Inc.
  *
@@ -191,6 +191,23 @@ CBS_get_u32(CBS *cbs, uint32_t *out)
 }
 
 int
+CBS_get_u64(CBS *cbs, uint64_t *out)
+{
+        uint32_t a, b;
+
+        if (cbs->len < 8)
+                return 0;
+
+        if (!CBS_get_u32(cbs, &a))
+                return 0;
+        if (!CBS_get_u32(cbs, &b))
+                return 0;
+
+        *out = (uint64_t)a << 32 | b;
+        return 1;
+}
+
+int
 CBS_get_last_u8(CBS *cbs, uint8_t *out)
 {
         if (cbs->len == 0)
diff --git a/src/lib/libssl/bytestring.h b/src/lib/libssl/bytestring.h
index 4ab2828d09..fa5e05fa27 100644
--- a/src/lib/libssl/bytestring.h
+++ b/src/lib/libssl/bytestring.h
@@ -1,4 +1,4 @@
-/*      $OpenBSD: bytestring.h,v 1.20 2021/12/15 17:23:34 jsing Exp $   */
+/*      $OpenBSD: bytestring.h,v 1.21 2021/12/15 17:30:20 jsing Exp $   */
 /*
  * Copyright (c) 2014, Google Inc.
  *
@@ -134,6 +134,12 @@ int CBS_get_u24(CBS *cbs, uint32_t *out);
 int CBS_get_u32(CBS *cbs, uint32_t *out);
 
 /*
+ * CBS_get_u64 sets |*out| to the next, big-endian uint64_t value from |cbs|
+ * and advances |cbs|. It returns one on success and zero on error.
+ */
+int CBS_get_u64(CBS *cbs, uint64_t *out);
+
+/*
  * CBS_get_last_u8 sets |*out| to the last uint8_t from |cbs| and shortens
  * |cbs|. It returns one on success and zero on error.
  */