kex, pki, server, options: Filter algorithms in FIPS mode

When in FIPS mode, filter the algorithms to enable only the allowed
ones.  If any algorithm is explicitly set through options or
configuration file, they are kept.

Signed-off-by: Anderson Toshiyuki Sasaki <ansasaki@redhat.com>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>

1 files changed, 21 insertions, 4 deletions

diff --git a/src/pki.c b/src/pki.c
index a65e8a48..d49eaa19 100644
--- a/src/pki.c
+++ b/src/pki.c
@@ -323,7 +323,11 @@ int ssh_key_algorithm_allowed(ssh_session session, const char *type)
     if (session->client) {
         allowed_list = session->opts.pubkey_accepted_types;
         if (allowed_list == NULL) {
-            allowed_list = ssh_kex_get_default_methods(SSH_HOSTKEYS);
+            if (ssh_fips_mode()) {
+                allowed_list = ssh_kex_get_fips_methods(SSH_HOSTKEYS);
+            } else {
+                allowed_list = ssh_kex_get_default_methods(SSH_HOSTKEYS);
+            }
         }
     }
 #ifdef WITH_SERVER
@@ -2111,13 +2115,26 @@ int pki_key_check_hash_compatible(ssh_key key,
     case SSH_KEYTYPE_DSS_CERT01:
     case SSH_KEYTYPE_DSS:
         if (hash_type == SSH_DIGEST_SHA1) {
-            return SSH_OK;
+            if (ssh_fips_mode()) {
+                SSH_LOG(SSH_LOG_WARN, "SHA1 is not allowed in FIPS mode");
+                return SSH_ERROR;
+            } else {
+                return SSH_OK;
+            }
         }
         break;
     case SSH_KEYTYPE_RSA_CERT01:
     case SSH_KEYTYPE_RSA:
-        if (hash_type == SSH_DIGEST_SHA1 ||
-            hash_type == SSH_DIGEST_SHA256 ||
+        if (hash_type == SSH_DIGEST_SHA1) {
+            if (ssh_fips_mode()) {
+                SSH_LOG(SSH_LOG_WARN, "SHA1 is not allowed in FIPS mode");
+                return SSH_ERROR;
+            } else {
+                return SSH_OK;
+            }
+        }
+
+        if (hash_type == SSH_DIGEST_SHA256 ||
             hash_type == SSH_DIGEST_SHA512)
         {
             return SSH_OK;