From 50873a820f9d9c655b93e8ff2d4158aff29761ff Mon Sep 17 00:00:00 2001 From: Martin Pitt Date: Mon, 8 Oct 2018 15:19:02 +0200 Subject: [PATCH 1/2] ssh: Use SHA256 fingerprints when available libssh 0.8 offers SHA256 fingerprints in addition to the old MD5/SHA1 ones. The latter are both cryptographically broken, and not allowed when running in FIPS mode -- these cause an assertion crash in OpenSSL. The "ssh" CLI hasn't shown MD5 fingerprints in a long time, not even on RHEL 7 (it shows SHA1 and SHA256 there by default), so this actually improves compatibility with ssh. Use libssh 0.8's ssh_get_fingerprint_hash() function, as ssh itself shows SHA256 fingerprints in base64 instead of hex. cockpit-ssh's fingerprint prompts should be compatible, and hex fingerprints would be overly long. Adjust most check-multi-machine tests to not care about the particular type of fingerprint, as they don't check the actual fingerprint anyway. Only `TestMultiMachine.testDirectLogin` does, so adjust the test to accept both MD5 and SHA256 fingerprints. https://bugzilla.redhat.com/show_bug.cgi?id=1585191 Closes #10241 --- configure.ac | 2 ++ src/ssh/cockpitsshrelay.c | 17 +++++++++++++++-- src/ssh/test-sshbridge.c | 8 +++++++- 3 files changed, 24 insertions(+), 3 deletions(-) diff --git a/configure.ac b/configure.ac index af8b1e3..b0d4879 100644 --- a/configure.ac +++ b/configure.ac @@ -132,6 +132,8 @@ if test "$enable_ssh" != "no"; then AC_DEFINE_UNQUOTED(HAVE_SSH_GET_SERVER_PUBLICKEY, 1, Whether ssh_get_server_publickey is available) ]) + AC_CHECK_DECLS([SSH_PUBLICKEY_HASH_SHA256, ssh_get_fingerprint_hash], [], [], [[#include ]]) + COCKPIT_SSH_SESSION_CFLAGS="$COCKPIT_CFLAGS $LIBSSH_CFLAGS $KRB5_CFLAGS" COCKPIT_SSH_SESSION_LIBS="$COCKPIT_LIBS $LIBSSH_LIBS $KRB5_LIBS" AC_SUBST(COCKPIT_SSH_SESSION_LIBS) diff --git a/src/ssh/cockpitsshrelay.c b/src/ssh/cockpitsshrelay.c index 41286c3..1798345 100644 --- a/src/ssh/cockpitsshrelay.c +++ b/src/ssh/cockpitsshrelay.c @@ -52,6 +52,15 @@ #include #include +/* libssh 0.8 offers SHA256 fingerprints, use them if available */ +#if HAVE_DECL_SSH_PUBLICKEY_HASH_SHA256 +#define SSH_PUBLICKEY_HASH SSH_PUBLICKEY_HASH_SHA256 +#define SSH_PUBLICKEY_HASH_NAME "SHA256" +#else +#define SSH_PUBLICKEY_HASH SSH_PUBLICKEY_HASH_MD5 +#define SSH_PUBLICKEY_HASH_NAME "MD5" +#endif + /* we had a private one before moving to /etc/ssh/ssh_known_hosts */ #define LEGACY_KNOWN_HOSTS PACKAGE_LOCALSTATE_DIR "/known_hosts" @@ -505,7 +514,7 @@ prompt_for_host_key (CockpitSshData *data) message = g_strdup_printf ("The authenticity of host '%s:%d' can't be established. Do you want to proceed this time?", host, port); - prompt = g_strdup_printf ("MD5 Fingerprint (%s):", data->host_key_type); + prompt = g_strdup_printf (SSH_PUBLICKEY_HASH_NAME " Fingerprint (%s):", data->host_key_type); reply = prompt_with_authorize (data, prompt, message, data->host_fingerprint, data->host_key, TRUE); @@ -674,7 +683,7 @@ verify_knownhost (CockpitSshData *data, goto done; } - if (ssh_get_publickey_hash (key, SSH_PUBLICKEY_HASH_MD5, &hash, &len) < 0) + if (ssh_get_publickey_hash (key, SSH_PUBLICKEY_HASH, &hash, &len) < 0) { g_warning ("Couldn't hash ssh public key"); ret = "internal-error"; @@ -682,7 +691,11 @@ verify_knownhost (CockpitSshData *data, } else { +#if HAVE_DECL_SSH_GET_FINGERPRINT_HASH + data->host_fingerprint = ssh_get_fingerprint_hash (SSH_PUBLICKEY_HASH, hash, len); +#else data->host_fingerprint = ssh_get_hexa (hash, len); +#endif ssh_clean_pubkey_hash (&hash); } diff --git a/src/ssh/test-sshbridge.c b/src/ssh/test-sshbridge.c index e86f639..bc5bc3a 100644 --- a/src/ssh/test-sshbridge.c +++ b/src/ssh/test-sshbridge.c @@ -563,7 +563,13 @@ test_echo_large (TestCase *tc, static const gchar MOCK_RSA_KEY[] = "ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQCYzo07OA0H6f7orVun9nIVjGYrkf8AuPDScqWGzlKpAqSipoQ9oY/mwONwIOu4uhKh7FTQCq5p+NaOJ6+Q4z++xBzSOLFseKX+zyLxgNG28jnF06WSmrMsSfvPdNuZKt9rZcQFKn9fRNa8oixa+RsqEEVEvTYhGtRf7w2wsV49xIoIza/bln1ABX1YLaCByZow+dK3ZlHn/UU0r4ewpAIZhve4vCvAsMe5+6KJH8ft/OKXXQY06h6jCythLV4h18gY/sYosOa+/4XgpmBiE7fDeFRKVjP3mvkxMpxce+ckOFae2+aJu51h513S9kxY2PmKaV/JU9HBYO+yO4j+j24v"; +#if HAVE_DECL_SSH_PUBLICKEY_HASH_SHA256 +static const gchar MOCK_RSA_FP[] = "SHA256:XQ8a7zGxMFstDrGecBRUP9OMnOUXd/T3vkNGtYShs2w"; +#define SSH_PUBLICKEY_HASH_NAME "SHA256" +#else static const gchar MOCK_RSA_FP[] = "0e:6a:c8:b1:07:72:e2:04:95:9f:0e:b3:56:af:48:e2"; +#define SSH_PUBLICKEY_HASH_NAME "MD5" +#endif static void @@ -634,7 +640,7 @@ do_hostkey_conversation (TestCase *tc, (int)tc->ssh_port, MOCK_RSA_FP, (int)tc->ssh_port, MOCK_RSA_KEY); - do_auth_conversation (tc->transport, "MD5 Fingerprint (ssh-rsa):", + do_auth_conversation (tc->transport, SSH_PUBLICKEY_HASH_NAME " Fingerprint (ssh-rsa):", expect_json, response, add_header); g_free (expect_json); } -- 2.19.1