add mbedtls crypto support

Summary:
This patch adds support for mbedTLS as a crypto backend for libssh.
mbedTLS is an SSL/TLS library that has been designed to mainly be used
in embedded systems.  It is loosely coupled and has a low memory
footprint.  mbedTLS also provides a cryptography library (libmbedcrypto)
that can be used without the TLS modules.
The patch is unfortunately quite big, since several new files had to
be added.
DSA is disabled at compile time, since mbedTLS doesn't support DSA
Patch review and feedback would be appreciated, and if any issues or
suggestions appear, I'm willing to work on them.

Signed-off-by: Juraj Vijtiuk <juraj.vijtiuk@sartura.hr>

Test Plan:
* The patch has been tested with a Debug and MinSizeRel build, with
libssh unit tests, client tests and the pkd tests.
* All the tests have been run with valgrind's memcheck, drd and helgrind
tools.
* The examples/samplessh client works when built with the patch.

Reviewers: asn, aris

Subscribers: simonsj

Differential Revision: https://bugs.libssh.org/D1

1 files changed, 14 insertions, 0 deletions

diff --git a/tests/client/torture_knownhosts.c b/tests/client/torture_knownhosts.c
index 1702b467..cfa47deb 100644
--- a/tests/client/torture_knownhosts.c
+++ b/tests/client/torture_knownhosts.c
@@ -40,6 +40,7 @@
                "YgIytryNn7LLiwYfoSxvWigFrTTZsrVtCOYyNgklmffpGdzuC43wdANvTewfI9G" \
                "o71r8EXmEc228CrYPmb8Scv3mpXFK/BosohSGkPlEHu9lf3YjnknBicDaVtJOYp" \
                "wnXJPjZo2EhG79HxDRpjJHH"
+#ifdef HAVE_DSA
 #define BADDSA "AAAAB3NzaC1kc3MAAACBAITDKqGQ5aC5wHySG6ZdL1+BVBY2nLP5vzw3i3pvZfP" \
                "yNUS0UCwrt5pajsMvDRGXXebTJhWVonDnv8tpSgiuIBXMZrma8CU1KCFGRzwb/n8" \
                "cc5tJmIphlOUTrObjBmsRz7u1eZmoaddXC9ask6BNnt0DmhzYi2esL3mbardy8IN" \
@@ -50,6 +51,7 @@
                "EcxqLVllrNEvd2EGD9p16BYO2yaalYon8im59PtOcul2ay5XQ6rVDQ2T0pgNUpsI" \
                "h0dSi8VJXI1wes5HTyLsv9VBmU1uCXUUvufoQKfF/OcSH0ufcCpnd62g1/adZcy2" \
                "WJg=="
+#endif
 
 static int sshd_setup(void **state)
 {
@@ -187,6 +189,7 @@ static void torture_knownhosts_fail(void **state) {
     assert_int_equal(rc, SSH_SERVER_KNOWN_CHANGED);
 }
 
+#ifdef HAVE_DSA
 static void torture_knownhosts_other(void **state) {
     struct torture_state *s = *state;
     ssh_session session = s->ssh.session;
@@ -272,6 +275,7 @@ static void torture_knownhosts_other_auto(void **state) {
 
     /* session will be freed by session_teardown() */
 }
+#endif
 
 static void torture_knownhosts_conflict(void **state) {
     struct torture_state *s = *state;
@@ -298,7 +302,9 @@ static void torture_knownhosts_conflict(void **state) {
     file = fopen(known_hosts_file, "w");
     assert_true(file != NULL);
     fprintf(file, "127.0.0.10 ssh-rsa %s\n", BADRSA);
+#ifdef HAVE_DSA
     fprintf(file, "127.0.0.10 ssh-dss %s\n", BADDSA);
+#endif
     fclose(file);
 
     rc = ssh_connect(session);
@@ -356,15 +362,21 @@ static void torture_knownhosts_precheck(void **state) {
     file = fopen(known_hosts_file, "w");
     assert_true(file != NULL);
     fprintf(file, "127.0.0.10 ssh-rsa %s\n", BADRSA);
+#ifdef HAVE_DSA
     fprintf(file, "127.0.0.10 ssh-dss %s\n", BADDSA);
+#endif
     fclose(file);
 
     kex = ssh_knownhosts_algorithms(session);
     assert_true(kex != NULL);
     assert_string_equal(kex[0],"ssh-rsa");
+#ifdef HAVE_DSA
     assert_string_equal(kex[1],"ssh-dss");
     assert_true(kex[2]==NULL);
     free(kex[1]);
+#else
+    assert_true(kex[1]==NULL);
+#endif
     free(kex[0]);
     free(kex);
 }
@@ -378,12 +390,14 @@ int torture_run_tests(void) {
         cmocka_unit_test_setup_teardown(torture_knownhosts_fail,
                                         session_setup,
                                         session_teardown),
+#ifdef HAVE_DSA
         cmocka_unit_test_setup_teardown(torture_knownhosts_other,
                                         session_setup,
                                         session_teardown),
         cmocka_unit_test_setup_teardown(torture_knownhosts_other_auto,
                                         session_setup,
                                         session_teardown),
+#endif
         cmocka_unit_test_setup_teardown(torture_knownhosts_conflict,
                                         session_setup,
                                         session_teardown),