From 9f25b8deff8e5b8fad8493db421b4639f14d2e5d Mon Sep 17 00:00:00 2001
From: jiblime <47689567+jiblime@users.noreply.github.com>
Date: Wed, 18 Dec 2019 21:40:01 -0800
Subject: [PATCH 1/2] Fixes definition error when the deprecated
 MBEDTLS_ZLIB_SUPPORT and ENABLE_ZLIB_SUPPORT macro are defined/enabled for
 zlib support in mbedtls

100% tests passed, 0 tests failed out of 85

https://github.com/ARMmbed/mbedtls/blob/mbedtls-2.19.1/library/ssl_tls.c#L1842

https://github.com/ARMmbed/mbedtls/blob/mbedtls-2.19.1/library/ssl_tls.c#L1862
---
 library/ssl_tls.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index 6cf7781f2..51ae9da3c 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -1880,7 +1880,7 @@ int mbedtls_ssl_derive_keys( mbedtls_ssl_context *ssl )
 
     /* Allocate compression buffer */
 #if defined(MBEDTLS_ZLIB_SUPPORT)
-    if( session->compression == MBEDTLS_SSL_COMPRESS_DEFLATE &&
+    if( ssl->session_negotiate->compression == MBEDTLS_SSL_COMPRESS_DEFLATE &&
         ssl->compress_buf == NULL )
     {
         MBEDTLS_SSL_DEBUG_MSG( 3, ( "Allocating compression buffer" ) );

From 80fcacebdbf5ce48484f7336c8513ca0d00f3234 Mon Sep 17 00:00:00 2001
From: Gilles Peskine <Gilles.Peskine@arm.com>
Date: Wed, 22 Jan 2020 19:18:35 +0100
Subject: [PATCH 2/2] Add changelog entry for the zlib support fix

---
 ChangeLog | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/ChangeLog b/ChangeLog
index 1d3917221..58f0e72d5 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,11 @@
 mbed TLS ChangeLog (Sorted per branch, date)
 
+= mbed TLS x.x.x branch released xxxx-xx-xx
+
+Bugfix
+   * Fix build failure with MBEDTLS_ZLIB_SUPPORT enabled. Reported by
+     Jack Lloyd in #2859. Fix submitted by jiblime in #2963.
+
 = mbed TLS 2.20.0 branch released 2020-01-15
 
 Bugfix