Release read and write buffers using freezero().

Provide a ssl3_release_buffer() function that correctly frees a buffer
and call it from the appropriate locations. While here also change
ssl3_release_{read,write}_buffer() to void since they cannot fail and
no callers check the return value currently.

ok beck@ inoguchi@ tb@

1 files changed, 15 insertions, 11 deletions

diff --git a/lib/libssl/ssl_both.c b/lib/libssl/ssl_both.c
index 488a5ff7c93..dff44ecd415 100644
--- a/lib/libssl/ssl_both.c
+++ b/lib/libssl/ssl_both.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssl_both.c,v 1.18 2020/05/19 16:35:20 jsing Exp $ */
+/* $OpenBSD: ssl_both.c,v 1.19 2020/09/24 17:59:54 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -708,7 +708,7 @@ ssl3_setup_read_buffer(SSL *s)
 		S3I(s)->rbuf.len = len;
 	}
 
-	s->internal->packet = &(S3I(s)->rbuf.buf[0]);
+	s->internal->packet = S3I(s)->rbuf.buf;
 	return 1;
 
 err:
@@ -759,18 +759,22 @@ ssl3_setup_buffers(SSL *s)
 	return 1;
 }
 
-int
-ssl3_release_write_buffer(SSL *s)
+void
+ssl3_release_buffer(SSL3_BUFFER_INTERNAL *b)
 {
-	free(S3I(s)->wbuf.buf);
-	S3I(s)->wbuf.buf = NULL;
-	return 1;
+	freezero(b->buf, b->len);
+	b->buf = NULL;
+	b->len = 0;
 }
 
-int
+void
 ssl3_release_read_buffer(SSL *s)
 {
-	free(S3I(s)->rbuf.buf);
-	S3I(s)->rbuf.buf = NULL;
-	return 1;
+	ssl3_release_buffer(&S3I(s)->rbuf);
+}
+
+void
+ssl3_release_write_buffer(SSL *s)
+{
+	ssl3_release_buffer(&S3I(s)->wbuf);
 }