upstream: Make zlib optional. This adds a "ZLIB" build time option

that allows building without zlib compression and associated options.  With
feedback from markus@, ok djm@

OpenBSD-Commit-ID: 44c6e1133a90fd15a3aa865bdedc53bab28b7910

1 files changed, 36 insertions, 2 deletions

diff --git a/packet.c b/packet.c
index 2b50ef415..cffadd9a4 100644
--- a/packet.c
+++ b/packet.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: packet.c,v 1.287 2019/12/16 13:58:53 tobhe Exp $ */
+/* $OpenBSD: packet.c,v 1.288 2020/01/23 10:24:29 dtucker Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -76,7 +76,9 @@
 # endif
 #endif
 
+#ifdef WITH_ZLIB
 #include <zlib.h>
+#endif
 
 #include "xmalloc.h"
 #include "compat.h"
@@ -150,9 +152,11 @@ struct session_state {
         /* Scratch buffer for packet compression/decompression. */
         struct sshbuf *compression_buffer;
 
+#ifdef WITH_ZLIB
         /* Incoming/outgoing compression dictionaries */
         z_stream compression_in_stream;
         z_stream compression_out_stream;
+#endif
         int compression_in_started;
         int compression_out_started;
         int compression_in_failures;
@@ -609,7 +613,8 @@ ssh_packet_close_internal(struct ssh *ssh, int do_close)
                 state->newkeys[mode] = NULL;
                 ssh_clear_newkeys(ssh, mode);           /* next keys */
         }
-        /* compression state is in shared mem, so we can only release it once */
+#ifdef WITH_ZLIB
+        /* comression state is in shared mem, so we can only release it once */
         if (do_close && state->compression_buffer) {
                 sshbuf_free(state->compression_buffer);
                 if (state->compression_out_started) {
@@ -635,6 +640,7 @@ ssh_packet_close_internal(struct ssh *ssh, int do_close)
                                 inflateEnd(stream);
                 }
         }
+#endif  /* WITH_ZLIB */
         cipher_free(state->send_context);
         cipher_free(state->receive_context);
         state->send_context = state->receive_context = NULL;
@@ -690,6 +696,7 @@ ssh_packet_init_compression(struct ssh *ssh)
         return 0;
 }
 
+#ifdef WITH_ZLIB
 static int
 start_compression_out(struct ssh *ssh, int level)
 {
@@ -821,6 +828,33 @@ uncompress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out)
         /* NOTREACHED */
 }
 
+#else   /* WITH_ZLIB */
+
+static int
+start_compression_out(struct ssh *ssh, int level)
+{
+        return SSH_ERR_INTERNAL_ERROR;
+}
+
+static int
+start_compression_in(struct ssh *ssh)
+{
+        return SSH_ERR_INTERNAL_ERROR;
+}
+
+static int
+compress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out)
+{
+        return SSH_ERR_INTERNAL_ERROR;
+}
+
+static int
+uncompress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out)
+{
+        return SSH_ERR_INTERNAL_ERROR;
+}
+#endif  /* WITH_ZLIB */
+
 void
 ssh_clear_newkeys(struct ssh *ssh, int mode)
 {