tests: add tests for injection rejection in ssh exec

tests/libgit2/transport/ssh_exec.c

+#include "clar_libgit2.h"
+#include "git2/sys/remote.h"
+#include "git2/sys/transport.h"
+
+
+void test_transport_ssh_exec__reject_injection_username(void)
+{
+#ifndef GIT_SSH_EXEC
+	cl_skip();
+#else
+	git_remote *remote;
+	git_repository *repo;
+	git_transport *transport;
+	const char *url = "-oProxyCommand=git@somehost:somepath";
+	git_remote_connect_options opts = GIT_REMOTE_CONNECT_OPTIONS_INIT;
+
+
+	cl_git_pass(git_repository_init(&repo, "./transport-username", 0));
+	cl_git_pass(git_remote_create(&remote, repo, "test",
+				      cl_fixture("testrepo.git")));
+	cl_git_pass(git_transport_new(&transport, remote, url));
+	cl_git_fail_with(-1, transport->connect(transport, url,
+						GIT_SERVICE_UPLOADPACK_LS, &opts));
+
+	transport->free(transport);
+	git_remote_free(remote);
+	git_repository_free(repo);
+#endif
+}
+
+void test_transport_ssh_exec__reject_injection_hostname(void)
+{
+#ifndef GIT_SSH_EXEC
+	cl_skip();
+#else
+	git_remote *remote;
+	git_repository *repo;
+	git_transport *transport;
+	const char *url = "-oProxyCommand=somehost:somepath-hostname";
+	git_remote_connect_options opts = GIT_REMOTE_CONNECT_OPTIONS_INIT;
+
+
+	cl_git_pass(git_repository_init(&repo, "./transport-hostname", 0));
+	cl_git_pass(git_remote_create(&remote, repo, "test",
+				      cl_fixture("testrepo.git")));
+	cl_git_pass(git_transport_new(&transport, remote, url));
+	cl_git_fail_with(-1, transport->connect(transport, url,
+						GIT_SERVICE_UPLOADPACK_LS, &opts));
+
+	transport->free(transport);
+	git_remote_free(remote);
+	git_repository_free(repo);
+#endif
+}
+
+void test_transport_ssh_exec__reject_injection_path(void)
+{
+#ifndef GIT_SSH_EXEC
+	cl_skip();
+#else
+	git_remote *remote;
+	git_repository *repo;
+	git_transport *transport;
+	const char *url = "git@somehost:-somepath";
+	git_remote_connect_options opts = GIT_REMOTE_CONNECT_OPTIONS_INIT;
+
+
+	cl_git_pass(git_repository_init(&repo, "./transport-path", 0));
+	cl_git_pass(git_remote_create(&remote, repo, "test",
+				      cl_fixture("testrepo.git")));
+	cl_git_pass(git_transport_new(&transport, remote, url));
+	cl_git_fail_with(-1, transport->connect(transport, url,
+						GIT_SERVICE_UPLOADPACK_LS, &opts));
+
+	transport->free(transport);
+	git_remote_free(remote);
+	git_repository_free(repo);
+#endif
+}