Add: Create krb5 config per IP

The default for the krb5 config was /etc/krb5.conf which. This now changes and for each IP a separate config is created in /tmp/krb5_<ip>.conf. These are also cleaned up.

Author: Kraemii

nasl/exec.c

@@ -15,6 +15,7 @@
 #include "nasl_func.h"
 #include "nasl_global_ctxt.h"
 #include "nasl_init.h"
+#include "nasl_krb5.h" /* for nasl_okrb5_clean */
 #include "nasl_lex_ctxt.h"
 #include "nasl_tree.h"
 #include "nasl_var.h"
@@ -1745,6 +1746,7 @@ exec_nasl_script (struct script_infos *script_infos, int mode)
     }
   g_free (old_dir);
 
+  nasl_okrb5_clean ();
   nasl_clean_ctx (&ctx);
   free_lex_ctxt (lexic);
   return err;

nasl/nasl_krb5.c

@@ -12,7 +12,11 @@
 #include "nasl_tree.h"
 #include "nasl_var.h"
 
+#include <gvm/base/networking.h>
+#include <netinet/in.h>
 #include <stdio.h>
+#include <string.h>
+#include <unistd.h>
 
 #define NASL_PRINT_KRB_ERROR(lexic, credential, result)                   \
   do                                                                      \
@@ -35,19 +39,22 @@ static OKrb5ErrorCode last_okrb5_result;
 // cached_gss_context is used on cases that require an already existing session.
 // NASL does currently not have the concept of a pointer nor struct so we need
 // to store it as a global variable.
-// 
+//
 // We use one context per run, this means that per run (target + oid) there is
 // only on credential allowed making it safe to be cached in that fashion.
 static struct OKrb5GSSContext *cached_gss_context = NULL;
 
-// Is used for `krb5_gss_update_context_out` and is essential a 
-// cache for the data from `krb5_gss_update_context`. 
+// Is used for `krb5_gss_update_context_out` and is essential a
+// cache for the data from `krb5_gss_update_context`.
 static struct OKrb5Slice *to_application = NULL;
 
 // Is used for `krb5_gss_update_context_needs_more` which indicates to the
-// script author that `krb5_gss_update_context` is not satisfied yet. 
+// script author that `krb5_gss_update_context` is not satisfied yet.
 static bool gss_update_context_more = false;
 
+// Stores the path to the generated krb5 config file for cleanup.
+static char *generated_config_path = NULL;
+
 #define SET_SLICE_FROM_LEX_OR_ENV(lexic, slice, name, env_name)            \
   do                                                                       \
     {                                                                      \
@@ -71,7 +78,6 @@ static bool gss_update_context_more = false;
     }                                                                  \
   while (0)
 
-
 static OKrb5Credential
 build_krb5_credential (lex_ctxt *lexic)
 {
@@ -84,9 +90,26 @@ build_krb5_credential (lex_ctxt *lexic)
                              "KRB5_CONFIG");
   if (credential.config_path.len == 0)
     {
-      okrb5_set_slice_from_str (credential.config_path, "/etc/krb5.conf");
+      char *ip_str = addr6_as_str (lexic->script_infos->ip);
+      for (int i = 0; ip_str[i] != '\0'; i++)
+        {
+          if (ip_str[i] == '.' || ip_str[i] == ':')
+            {
+              ip_str[i] = '_';
+            }
+        }
+      char default_config_path[256];
+      snprintf (default_config_path, sizeof (default_config_path),
+                "/tmp/krb5_%s.conf", ip_str);
+      okrb5_set_slice_from_str (credential.config_path, default_config_path);
     }
 
+  // Store path for cleanup
+  if (generated_config_path != NULL)
+    free (generated_config_path);
+  generated_config_path =
+    strndup (credential.config_path.data, credential.config_path.len);
+
   PERROR_SET_SLICE_FROM_LEX_OR_ENV (lexic, credential.realm, "realm",
                                     "KRB5_REALM");
   PERROR_SET_SLICE_FROM_LEX_OR_ENV (lexic, credential.kdc, "kdc", "KRB5_KDC");
@@ -240,7 +263,6 @@ nasl_okrb5_is_failure (lex_ctxt *lexic)
   return retc;
 }
 
-
 tree_cell *
 nasl_okrb5_gss_init (lex_ctxt *lexic)
 {
@@ -277,7 +299,6 @@ nasl_okrb5_gss_prepare_context (lex_ctxt *lexic)
   return retc;
 }
 
-
 tree_cell *
 nasl_okrb5_gss_update_context (lex_ctxt *lexic)
 {
@@ -322,6 +343,13 @@ nasl_okrb5_clean (void)
   if (cached_gss_context != NULL)
     {
       okrb5_gss_free_context (cached_gss_context);
+      cached_gss_context = NULL;
+    }
+  if (generated_config_path != NULL)
+    {
+      unlink (generated_config_path);
+      free (generated_config_path);
+      generated_config_path = NULL;
     }
 }
 

src/openvas.c

@@ -26,7 +26,6 @@
 #include "../misc/plugutils.h"     /* nvticache_free */
 #include "../misc/scan_id.h"       /* to manage global scan_id */
 #include "../misc/vendorversion.h" /* for vendor_version_set */
-#include "../nasl/nasl_krb5.h"     /* for nasl_okrb5_clean */
 #include "attack.h"                /* for attack_network */
 #include "debug_utils.h"           /* for init_sentry */
 #include "pluginlaunch.h"          /* for init_loading_shm */
@@ -641,7 +640,6 @@ openvas (int argc, char *argv[], char *env[])
 
       gvm_close_sentry ();
       destroy_scan_globals (globals);
-      nasl_okrb5_clean ();
 #ifdef LOG_REFERENCES_AVAILABLE
       free_log_reference ();
 #endif // LOG_REFERENCES_AVAILABLE