chacha: fix build for mbedTLS

Fix the build for mbedTLS:
 * set HAVE_CHACHA for non-mbedTLS builds
 * only compile chachapoly.c when HAVE_CHACHA
 * use empty CHACHA20 in src/kex.c unless HAVE_CHACHA

Signed-off-by: Jon Simons <jon@jonsimons.org>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>

4 files changed, 16 insertions, 2 deletions

diff --git a/ConfigureChecks.cmake b/ConfigureChecks.cmake
index fd8ff136..3bb4a5e0 100644
--- a/ConfigureChecks.cmake
+++ b/ConfigureChecks.cmake
@@ -138,7 +138,8 @@ endif ()
 
 if (NOT WITH_MBEDTLS)
     set(HAVE_DSA 1)
-endif()
+    set(HAVE_CHACHA 1)
+endif (NOT WITH_MBEDTLS)
 
 # FUNCTIONS
 
diff --git a/config.h.cmake b/config.h.cmake
index 61d20acb..044e6032 100644
--- a/config.h.cmake
+++ b/config.h.cmake
@@ -89,6 +89,9 @@
 /* Define to 1 if you have DSA */
 #cmakedefine HAVE_DSA 1
 
+/* Define to 1 if you have chacha20-poly1305 */
+#cmakedefine HAVE_CHACHA 1
+
 /*************************** FUNCTIONS ***************************/
 
 /* Define to 1 if you have the `EVP_aes128_ctr' function. */
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 90e44253..4edc59f4 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -122,7 +122,6 @@ set(libssh_SRCS
   bignum.c
   buffer.c
   callbacks.c
-  chachapoly.c
   channels.c
   client.c
   config.c
@@ -167,6 +166,13 @@ set(libssh_SRCS
   external/sc25519.c
 )
 
+if (NOT WITH_MBEDTLS)
+    set(libssh_SRCS
+        ${libssh_SRCS}
+        chachapoly.c
+       )
+endif (NOT WITH_MBEDTLS)
+
 if (WITH_GCRYPT)
     set(libssh_SRCS
         ${libssh_SRCS}
diff --git a/src/kex.c b/src/kex.c
index 00f4e00f..8c51566e 100644
--- a/src/kex.c
+++ b/src/kex.c
@@ -95,7 +95,11 @@
 #define ECDH ""
 #endif
 
+#ifdef    HAVE_CHACHA
 #define CHACHA20 "chacha20-poly1305@openssh.com,"
+#else  /* HAVE_CHACHA */
+#define CHACHA20
+#endif /* HAVE_CHACHA */
 
 #define KEY_EXCHANGE CURVE25519 ECDH "diffie-hellman-group14-sha1,diffie-hellman-group1-sha1"
 #define KEX_METHODS_SIZE 10