sepgsql: Move some code from hooks.c to label.c
authorRobert Haas
Wed, 15 Feb 2012 18:54:26 +0000 (13:54 -0500)
committerRobert Haas
Wed, 15 Feb 2012 18:54:26 +0000 (13:54 -0500)
This is some preliminary refactoring related to a pending patch
to allow sepgsql-enable sessions to make dynamic label transitions.
But this commit doesn't involve any functional change: it just puts
some bits of code in more logical places.

KaiGai Kohei

contrib/sepgsql/hooks.c
contrib/sepgsql/label.c
contrib/sepgsql/sepgsql.h

index 47437ba5b312eb344f40715e5663b9dccb55653c..70934950e51d32454df010cd0a43b8101d146f06 100644 (file)
@@ -18,7 +18,6 @@
 #include "commands/seclabel.h"
 #include "executor/executor.h"
 #include "fmgr.h"
-#include "libpq/auth.h"
 #include "miscadmin.h"
 #include "tcop/utility.h"
 #include "utils/guc.h"
@@ -36,10 +35,7 @@ void     _PG_init(void);
  * Saved hook entries (if stacked)
  */
 static object_access_hook_type next_object_access_hook = NULL;
-static ClientAuthentication_hook_type next_client_auth_hook = NULL;
 static ExecutorCheckPerms_hook_type next_exec_check_perms_hook = NULL;
-static needs_fmgr_hook_type next_needs_fmgr_hook = NULL;
-static fmgr_hook_type next_fmgr_hook = NULL;
 static ProcessUtility_hook_type next_ProcessUtility_hook = NULL;
 static ExecutorStart_hook_type next_ExecutorStart_hook = NULL;
 
@@ -81,48 +77,6 @@ sepgsql_get_debug_audit(void)
    return sepgsql_debug_audit;
 }
 
-/*
- * sepgsql_client_auth
- *
- * Entrypoint of the client authentication hook.
- * It switches the client label according to getpeercon(), and the current
- * performing mode according to the GUC setting.
- */
-static void
-sepgsql_client_auth(Port *port, int status)
-{
-   char       *context;
-
-   if (next_client_auth_hook)
-       (*next_client_auth_hook) (port, status);
-
-   /*
-    * In the case when authentication failed, the supplied socket shall be
-    * closed soon, so we don't need to do anything here.
-    */
-   if (status != STATUS_OK)
-       return;
-
-   /*
-    * Getting security label of the peer process using API of libselinux.
-    */
-   if (getpeercon_raw(port->sock, &context) < 0)
-       ereport(FATAL,
-               (errcode(ERRCODE_INTERNAL_ERROR),
-                errmsg("SELinux: unable to get peer label: %m")));
-
-   sepgsql_set_client_label(context);
-
-   /*
-    * Switch the current performing mode from INTERNAL to either DEFAULT or
-    * PERMISSIVE.
-    */
-   if (sepgsql_permissive)
-       sepgsql_set_mode(SEPGSQL_MODE_PERMISSIVE);
-   else
-       sepgsql_set_mode(SEPGSQL_MODE_DEFAULT);
-}
-
 /*
  * sepgsql_object_access
  *
@@ -220,121 +174,6 @@ sepgsql_exec_check_perms(List *rangeTabls, bool abort)
    return true;
 }
 
-/*
- * sepgsql_needs_fmgr_hook
- *
- * It informs the core whether the supplied function is trusted procedure,
- * or not. If true, sepgsql_fmgr_hook shall be invoked at start, end, and
- * abort time of function invocation.
- */
-static bool
-sepgsql_needs_fmgr_hook(Oid functionId)
-{
-   ObjectAddress   object;
-
-   if (next_needs_fmgr_hook &&
-       (*next_needs_fmgr_hook) (functionId))
-       return true;
-
-   /*
-    * SELinux needs the function to be called via security_definer wrapper,
-    * if this invocation will take a domain-transition. We call these
-    * functions as trusted-procedure, if the security policy has a rule that
-    * switches security label of the client on execution.
-    */
-   if (sepgsql_avc_trusted_proc(functionId) != NULL)
-       return true;
-
-   /*
-    * Even if not a trusted-procedure, this function should not be inlined
-    * unless the client has db_procedure:{execute} permission. Please note
-    * that it shall be actually failed later because of same reason with
-    * ACL_EXECUTE.
-    */
-   object.classId = ProcedureRelationId;
-   object.objectId = functionId;
-   object.objectSubId = 0;
-   if (!sepgsql_avc_check_perms(&object,
-                                SEPG_CLASS_DB_PROCEDURE,
-                                SEPG_DB_PROCEDURE__EXECUTE,
-                                SEPGSQL_AVC_NOAUDIT, false))
-       return true;
-
-   return false;
-}
-
-/*
- * sepgsql_fmgr_hook
- *
- * It switches security label of the client on execution of trusted
- * procedures.
- */
-static void
-sepgsql_fmgr_hook(FmgrHookEventType event,
-                 FmgrInfo *flinfo, Datum *private)
-{
-   struct
-   {
-       char       *old_label;
-       char       *new_label;
-       Datum       next_private;
-   }          *stack;
-
-   switch (event)
-   {
-       case FHET_START:
-           stack = (void *) DatumGetPointer(*private);
-           if (!stack)
-           {
-               MemoryContext oldcxt;
-
-               oldcxt = MemoryContextSwitchTo(flinfo->fn_mcxt);
-               stack = palloc(sizeof(*stack));
-               stack->old_label = NULL;
-               stack->new_label = sepgsql_avc_trusted_proc(flinfo->fn_oid);
-               stack->next_private = 0;
-
-               MemoryContextSwitchTo(oldcxt);
-
-               /*
-                * process:transition permission between old and new label,
-                * when user tries to switch security label of the client
-                * on execution of trusted procedure.
-                */
-               if (stack->new_label)
-                   sepgsql_avc_check_perms_label(stack->new_label,
-                                                 SEPG_CLASS_PROCESS,
-                                                 SEPG_PROCESS__TRANSITION,
-                                                 NULL, true);
-
-               *private = PointerGetDatum(stack);
-           }
-           Assert(!stack->old_label);
-           if (stack->new_label)
-               stack->old_label = sepgsql_set_client_label(stack->new_label);
-
-           if (next_fmgr_hook)
-               (*next_fmgr_hook) (event, flinfo, &stack->next_private);
-           break;
-
-       case FHET_END:
-       case FHET_ABORT:
-           stack = (void *) DatumGetPointer(*private);
-
-           if (next_fmgr_hook)
-               (*next_fmgr_hook) (event, flinfo, &stack->next_private);
-
-           if (stack->old_label)
-               sepgsql_set_client_label(stack->old_label);
-           stack->old_label = NULL;
-           break;
-
-       default:
-           elog(ERROR, "unexpected event type: %d", (int) event);
-           break;
-   }
-}
-
 /*
  * sepgsql_executor_start
  *
@@ -465,8 +304,6 @@ sepgsql_utility_command(Node *parsetree,
 void
 _PG_init(void)
 {
-   char       *context;
-
    /*
     * We allow to load the SE-PostgreSQL module on single-user-mode or
     * shared_preload_libraries settings only.
@@ -522,33 +359,16 @@ _PG_init(void)
                             NULL,
                             NULL);
 
-   /*
-    * Set up dummy client label.
-    *
-    * XXX - note that PostgreSQL launches background worker process like
-    * autovacuum without authentication steps. So, we initialize sepgsql_mode
-    * with SEPGSQL_MODE_INTERNAL, and client_label with the security context
-    * of server process. Later, it also launches background of user session.
-    * In this case, the process is always hooked on post-authentication, and
-    * we can initialize the sepgsql_mode and client_label correctly.
-    */
-   if (getcon_raw(&context) < 0)
-       ereport(ERROR,
-               (errcode(ERRCODE_INTERNAL_ERROR),
-                errmsg("SELinux: failed to get server security label: %m")));
-   sepgsql_set_client_label(context);
-
    /* Initialize userspace access vector cache */
    sepgsql_avc_init();
 
+   /* Initialize security label of the client and related stuff */
+   sepgsql_init_client_label();
+
    /* Security label provider hook */
    register_label_provider(SEPGSQL_LABEL_TAG,
                            sepgsql_object_relabel);
 
-   /* Client authentication hook */
-   next_client_auth_hook = ClientAuthentication_hook;
-   ClientAuthentication_hook = sepgsql_client_auth;
-
    /* Object access hook */
    next_object_access_hook = object_access_hook;
    object_access_hook = sepgsql_object_access;
@@ -557,13 +377,6 @@ _PG_init(void)
    next_exec_check_perms_hook = ExecutorCheckPerms_hook;
    ExecutorCheckPerms_hook = sepgsql_exec_check_perms;
 
-   /* Trusted procedure hooks */
-   next_needs_fmgr_hook = needs_fmgr_hook;
-   needs_fmgr_hook = sepgsql_needs_fmgr_hook;
-
-   next_fmgr_hook = fmgr_hook;
-   fmgr_hook = sepgsql_fmgr_hook;
-
    /* ProcessUtility hook */
    next_ProcessUtility_hook = ProcessUtility_hook;
    ProcessUtility_hook = sepgsql_utility_command;
index 2ab7a6f20359b28bdbc98cf60cda0aef35da884f..340bec6864caaa81777e404bbea1457a16357425 100644 (file)
@@ -22,6 +22,7 @@
 #include "catalog/pg_proc.h"
 #include "commands/dbcommands.h"
 #include "commands/seclabel.h"
+#include "libpq/auth.h"
 #include "libpq/libpq-be.h"
 #include "miscadmin.h"
 #include "utils/builtins.h"
 
 #include 
 
+/*
+ * Saved hook entries (if stacked)
+ */
+static ClientAuthentication_hook_type next_client_auth_hook = NULL;
+static needs_fmgr_hook_type next_needs_fmgr_hook = NULL;
+static fmgr_hook_type next_fmgr_hook = NULL;
+
 /*
  * client_label
  *
@@ -47,14 +55,197 @@ sepgsql_get_client_label(void)
    return client_label;
 }
 
-char *
-sepgsql_set_client_label(char *new_label)
+/*
+ * sepgsql_client_auth
+ *
+ * Entrypoint of the client authentication hook.
+ * It switches the client label according to getpeercon(), and the current
+ * performing mode according to the GUC setting.
+ */
+static void
+sepgsql_client_auth(Port *port, int status)
+{
+   if (next_client_auth_hook)
+       (*next_client_auth_hook) (port, status);
+
+   /*
+    * In the case when authentication failed, the supplied socket shall be
+    * closed soon, so we don't need to do anything here.
+    */
+   if (status != STATUS_OK)
+       return;
+
+   /*
+    * Getting security label of the peer process using API of libselinux.
+    */
+   if (getpeercon_raw(port->sock, &client_label) < 0)
+       ereport(FATAL,
+               (errcode(ERRCODE_INTERNAL_ERROR),
+                errmsg("SELinux: unable to get peer label: %m")));
+
+   /*
+    * Switch the current performing mode from INTERNAL to either DEFAULT or
+    * PERMISSIVE.
+    */
+   if (sepgsql_get_permissive())
+       sepgsql_set_mode(SEPGSQL_MODE_PERMISSIVE);
+   else
+       sepgsql_set_mode(SEPGSQL_MODE_DEFAULT);
+}
+
+/*
+ * sepgsql_needs_fmgr_hook
+ *
+ * It informs the core whether the supplied function is trusted procedure,
+ * or not. If true, sepgsql_fmgr_hook shall be invoked at start, end, and
+ * abort time of function invocation.
+ */
+static bool
+sepgsql_needs_fmgr_hook(Oid functionId)
 {
-   char       *old_label = client_label;
+   ObjectAddress   object;
+
+   if (next_needs_fmgr_hook &&
+       (*next_needs_fmgr_hook) (functionId))
+       return true;
+
+   /*
+    * SELinux needs the function to be called via security_definer wrapper,
+    * if this invocation will take a domain-transition. We call these
+    * functions as trusted-procedure, if the security policy has a rule that
+    * switches security label of the client on execution.
+    */
+   if (sepgsql_avc_trusted_proc(functionId) != NULL)
+       return true;
+
+   /*
+    * Even if not a trusted-procedure, this function should not be inlined
+    * unless the client has db_procedure:{execute} permission. Please note
+    * that it shall be actually failed later because of same reason with
+    * ACL_EXECUTE.
+    */
+   object.classId = ProcedureRelationId;
+   object.objectId = functionId;
+   object.objectSubId = 0;
+   if (!sepgsql_avc_check_perms(&object,
+                                SEPG_CLASS_DB_PROCEDURE,
+                                SEPG_DB_PROCEDURE__EXECUTE,
+                                SEPGSQL_AVC_NOAUDIT, false))
+       return true;
+
+   return false;
+}
+
+/*
+ * sepgsql_fmgr_hook
+ *
+ * It switches security label of the client on execution of trusted
+ * procedures.
+ */
+static void
+sepgsql_fmgr_hook(FmgrHookEventType event,
+                 FmgrInfo *flinfo, Datum *private)
+{
+   struct
+   {
+       char       *old_label;
+       char       *new_label;
+       Datum       next_private;
+   }          *stack;
+
+   switch (event)
+   {
+       case FHET_START:
+           stack = (void *) DatumGetPointer(*private);
+           if (!stack)
+           {
+               MemoryContext oldcxt;
+
+               oldcxt = MemoryContextSwitchTo(flinfo->fn_mcxt);
+               stack = palloc(sizeof(*stack));
+               stack->old_label = NULL;
+               stack->new_label = sepgsql_avc_trusted_proc(flinfo->fn_oid);
+               stack->next_private = 0;
+
+               MemoryContextSwitchTo(oldcxt);
+
+               /*
+                * process:transition permission between old and new label,
+                * when user tries to switch security label of the client
+                * on execution of trusted procedure.
+                */
+               if (stack->new_label)
+                   sepgsql_avc_check_perms_label(stack->new_label,
+                                                 SEPG_CLASS_PROCESS,
+                                                 SEPG_PROCESS__TRANSITION,
+                                                 NULL, true);
+
+               *private = PointerGetDatum(stack);
+           }
+           Assert(!stack->old_label);
+           if (stack->new_label)
+           {
+               stack->old_label = client_label;
+               client_label = stack->new_label;
+           }
+           if (next_fmgr_hook)
+               (*next_fmgr_hook) (event, flinfo, &stack->next_private);
+           break;
+
+       case FHET_END:
+       case FHET_ABORT:
+           stack = (void *) DatumGetPointer(*private);
+
+           if (next_fmgr_hook)
+               (*next_fmgr_hook) (event, flinfo, &stack->next_private);
+
+           if (stack->new_label)
+           {
+               client_label = stack->old_label;
+               stack->old_label = NULL;
+           }
+           break;
+
+       default:
+           elog(ERROR, "unexpected event type: %d", (int) event);
+           break;
+   }
+}
+
+/*
+ * sepgsql_init_client_label
+ *
+ * This routine initialize security label of the client, and set up related
+ * hooks to be invoked later.
+ */
+void
+sepgsql_init_client_label(void)
+{
+   /*
+    * Set up dummy client label.
+    *
+    * XXX - note that PostgreSQL launches background worker process like
+    * autovacuum without authentication steps. So, we initialize sepgsql_mode
+    * with SEPGSQL_MODE_INTERNAL, and client_label with the security context
+    * of server process. Later, it also launches background of user session.
+    * In this case, the process is always hooked on post-authentication, and
+    * we can initialize the sepgsql_mode and client_label correctly.
+    */
+   if (getcon_raw(&client_label) < 0)
+       ereport(ERROR,
+               (errcode(ERRCODE_INTERNAL_ERROR),
+                errmsg("SELinux: failed to get server security label: %m")));
+
+   /* Client authentication hook */
+   next_client_auth_hook = ClientAuthentication_hook;
+   ClientAuthentication_hook = sepgsql_client_auth;
 
-   client_label = new_label;
+   /* Trusted procedure hooks */
+   next_needs_fmgr_hook = needs_fmgr_hook;
+   needs_fmgr_hook = sepgsql_needs_fmgr_hook;
 
-   return old_label;
+   next_fmgr_hook = fmgr_hook;
+   fmgr_hook = sepgsql_fmgr_hook;
 }
 
 /*
index c93da7ad70b172354b7e91ef7155ec72823d6cbb..9ce8d2d9c482abca928e88508a99d1486f3bda20 100644 (file)
@@ -267,7 +267,7 @@ extern void sepgsql_avc_init(void);
  * label.c
  */
 extern char *sepgsql_get_client_label(void);
-extern char *sepgsql_set_client_label(char *new_label);
+extern void  sepgsql_init_client_label(void);
 extern char *sepgsql_get_label(Oid relOid, Oid objOid, int32 subId);
 
 extern void sepgsql_object_relabel(const ObjectAddress *object,