Only call free in CBB_init().

CBB_init_fixed() should not call free because it can lead to use after
free or double free bugs.  The caller should be responsible for
creating and destroying the buffer.

From BoringSSL commit a84f06fc1eee6ea25ce040675fbad72c532afece

miod agrees with the reasoning
ok jsing@, beck@

2 files changed, 12 insertions, 6 deletions

diff --git a/src/lib/libssl/bs_cbb.c b/src/lib/libssl/bs_cbb.c
index 94ca54f43b..eed8091698 100644
--- a/src/lib/libssl/bs_cbb.c
+++ b/src/lib/libssl/bs_cbb.c
@@ -1,4 +1,4 @@
-/*      $OpenBSD: bs_cbb.c,v 1.3 2015/02/06 22:22:33 doug Exp $ */
+/*      $OpenBSD: bs_cbb.c,v 1.4 2015/02/07 04:37:35 doug Exp $ */
 /*
  * Copyright (c) 2014, Google Inc.
  *
@@ -29,7 +29,6 @@ cbb_init(CBB *cbb, uint8_t *buf, size_t cap)
 
         base = malloc(sizeof(struct cbb_buffer_st));
         if (base == NULL) {
-                free(buf);
                 return 0;
         }
 
@@ -53,7 +52,11 @@ CBB_init(CBB *cbb, size_t initial_capacity)
         if (initial_capacity > 0 && buf == NULL)
                 return 0;
 
-        return cbb_init(cbb, buf, initial_capacity);
+        if (!cbb_init(cbb, buf, initial_capacity)) {
+                free(buf);
+                return 0;
+        }
+        return 1;
 }
 
 int
diff --git a/src/lib/libssl/src/ssl/bs_cbb.c b/src/lib/libssl/src/ssl/bs_cbb.c
index 94ca54f43b..eed8091698 100644
--- a/src/lib/libssl/src/ssl/bs_cbb.c
+++ b/src/lib/libssl/src/ssl/bs_cbb.c
@@ -1,4 +1,4 @@
-/*      $OpenBSD: bs_cbb.c,v 1.3 2015/02/06 22:22:33 doug Exp $ */
+/*      $OpenBSD: bs_cbb.c,v 1.4 2015/02/07 04:37:35 doug Exp $ */
 /*
  * Copyright (c) 2014, Google Inc.
  *
@@ -29,7 +29,6 @@ cbb_init(CBB *cbb, uint8_t *buf, size_t cap)
 
         base = malloc(sizeof(struct cbb_buffer_st));
         if (base == NULL) {
-                free(buf);
                 return 0;
         }
 
@@ -53,7 +52,11 @@ CBB_init(CBB *cbb, size_t initial_capacity)
         if (initial_capacity > 0 && buf == NULL)
                 return 0;
 
-        return cbb_init(cbb, buf, initial_capacity);
+        if (!cbb_init(cbb, buf, initial_capacity)) {
+                free(buf);
+                return 0;
+        }
+        return 1;
 }
 
 int