# for contrib/sepgsql
if test "$with_selinux" = yes; then
-{ $as_echo "$as_me:$LINENO: checking for selinux_sepgsql_context_path in -lselinux" >&5
-$as_echo_n "checking for selinux_sepgsql_context_path in -lselinux... " >&6; }
-if test "${ac_cv_lib_selinux_selinux_sepgsql_context_path+set}" = set; then
+{ $as_echo "$as_me:$LINENO: checking for selinux_status_open in -lselinux" >&5
+$as_echo_n "checking for selinux_status_open in -lselinux... " >&6; }
+if test "${ac_cv_lib_selinux_selinux_status_open+set}" = set; then
$as_echo_n "(cached) " >&6
else
ac_check_lib_save_LIBS=$LIBS
#ifdef __cplusplus
extern "C"
#endif
-char selinux_sepgsql_context_path ();
+char selinux_status_open ();
int
main ()
{
-return selinux_sepgsql_context_path ();
+return selinux_status_open ();
;
return 0;
}
test "$cross_compiling" = yes ||
$as_test_x conftest$ac_exeext
}; then
- ac_cv_lib_selinux_selinux_sepgsql_context_path=yes
+ ac_cv_lib_selinux_selinux_status_open=yes
else
$as_echo "$as_me: failed program was:" >&5
sed 's/^/| /' conftest.$ac_ext >&5
- ac_cv_lib_selinux_selinux_sepgsql_context_path=no
+ ac_cv_lib_selinux_selinux_status_open=no
fi
rm -rf conftest.dSYM
conftest$ac_exeext conftest.$ac_ext
LIBS=$ac_check_lib_save_LIBS
fi
-{ $as_echo "$as_me:$LINENO: result: $ac_cv_lib_selinux_selinux_sepgsql_context_path" >&5
-$as_echo "$ac_cv_lib_selinux_selinux_sepgsql_context_path" >&6; }
-if test "x$ac_cv_lib_selinux_selinux_sepgsql_context_path" = x""yes; then
+{ $as_echo "$as_me:$LINENO: result: $ac_cv_lib_selinux_selinux_status_open" >&5
+$as_echo "$ac_cv_lib_selinux_selinux_status_open" >&6; }
+if test "x$ac_cv_lib_selinux_selinux_status_open" = x""yes; then
cat >>confdefs.h <<_ACEOF
#define HAVE_LIBSELINUX 1
_ACEOF
LIBS="-lselinux $LIBS"
else
- { { $as_echo "$as_me:$LINENO: error: library 'libselinux', version 2.0.93 or newer, is required for SELinux support" >&5
-$as_echo "$as_me: error: library 'libselinux', version 2.0.93 or newer, is required for SELinux support" >&2;}
+ { { $as_echo "$as_me:$LINENO: error: library 'libselinux', version 2.0.99 or newer, is required for SELinux support" >&5
+$as_echo "$as_me: error: library 'libselinux', version 2.0.99 or newer, is required for SELinux support" >&2;}
{ (exit 1); exit 1; }; }
fi
# for contrib/sepgsql
if test "$with_selinux" = yes; then
- AC_CHECK_LIB(selinux, selinux_sepgsql_context_path, [],
- [AC_MSG_ERROR([library 'libselinux', version 2.0.93 or newer, is required for SELinux support])])
+ AC_CHECK_LIB(selinux, selinux_status_open, [],
+ [AC_MSG_ERROR([library 'libselinux', version 2.0.99 or newer, is required for SELinux support])])
fi
# for contrib/uuid-ossp
# contrib/sepgsql/Makefile
MODULE_big = sepgsql
-OBJS = hooks.o selinux.o label.o dml.o \
+OBJS = hooks.o selinux.o uavc.o label.o dml.o \
schema.o relation.o proc.o
DATA_built = sepgsql.sql
uint32 required,
bool abort)
{
- char relkind = get_rel_relkind(relOid);
- char *scontext = sepgsql_get_client_label();
- char *tcontext;
+ ObjectAddress object;
char *audit_name;
Bitmapset *columns;
int index;
+ char relkind = get_rel_relkind(relOid);
bool result = true;
/*
/*
* Check permissions on the relation
*/
- tcontext = sepgsql_get_label(RelationRelationId, relOid, 0);
- audit_name = getObjectDescriptionOids(RelationRelationId, relOid);
+ object.classId = RelationRelationId;
+ object.objectId = relOid;
+ object.objectSubId = 0;
+ audit_name = getObjectDescription(&object);
switch (relkind)
{
case RELKIND_RELATION:
- result = sepgsql_check_perms(scontext,
- tcontext,
- SEPG_CLASS_DB_TABLE,
- required,
- audit_name,
- abort);
+ result = sepgsql_avc_check_perms(&object,
+ SEPG_CLASS_DB_TABLE,
+ required,
+ audit_name,
+ abort);
break;
case RELKIND_SEQUENCE:
Assert((required & ~SEPG_DB_TABLE__SELECT) == 0);
if (required & SEPG_DB_TABLE__SELECT)
- result = sepgsql_check_perms(scontext,
- tcontext,
- SEPG_CLASS_DB_SEQUENCE,
- SEPG_DB_SEQUENCE__GET_VALUE,
- audit_name,
- abort);
+ result = sepgsql_avc_check_perms(&object,
+ SEPG_CLASS_DB_SEQUENCE,
+ SEPG_DB_SEQUENCE__GET_VALUE,
+ audit_name,
+ abort);
break;
case RELKIND_VIEW:
- result = sepgsql_check_perms(scontext,
- tcontext,
- SEPG_CLASS_DB_VIEW,
- SEPG_DB_VIEW__EXPAND,
- audit_name,
- abort);
+ result = sepgsql_avc_check_perms(&object,
+ SEPG_CLASS_DB_VIEW,
+ SEPG_DB_VIEW__EXPAND,
+ audit_name,
+ abort);
break;
default:
/* nothing to be checked */
break;
}
- pfree(tcontext);
pfree(audit_name);
/*
{
AttrNumber attnum;
uint32 column_perms = 0;
- ObjectAddress object;
if (bms_is_member(index, selected))
column_perms |= SEPG_DB_COLUMN__SELECT;
/* obtain column's permission */
attnum = index + FirstLowInvalidHeapAttributeNumber;
- tcontext = sepgsql_get_label(RelationRelationId, relOid, attnum);
object.classId = RelationRelationId;
object.objectId = relOid;
object.objectSubId = attnum;
audit_name = getObjectDescription(&object);
- result = sepgsql_check_perms(scontext,
- tcontext,
- SEPG_CLASS_DB_COLUMN,
- column_perms,
- audit_name,
- abort);
- pfree(tcontext);
+ result = sepgsql_avc_check_perms(&object,
+ SEPG_CLASS_DB_COLUMN,
+ column_perms,
+ audit_name,
+ abort);
pfree(audit_name);
if (!result)
static bool
sepgsql_needs_fmgr_hook(Oid functionId)
{
- char *old_label;
- char *new_label;
- char *function_label;
+ ObjectAddress object;
if (next_needs_fmgr_hook &&
(*next_needs_fmgr_hook) (functionId))
* functions as trusted-procedure, if the security policy has a rule that
* switches security label of the client on execution.
*/
- old_label = sepgsql_get_client_label();
- new_label = sepgsql_proc_get_domtrans(functionId);
- if (strcmp(old_label, new_label) != 0)
- {
- pfree(new_label);
+ if (sepgsql_avc_trusted_proc(functionId) != NULL)
return true;
- }
- pfree(new_label);
/*
* Even if not a trusted-procedure, this function should not be inlined
* that it shall be actually failed later because of same reason with
* ACL_EXECUTE.
*/
- function_label = sepgsql_get_label(ProcedureRelationId, functionId, 0);
- if (sepgsql_check_perms(sepgsql_get_client_label(),
- function_label,
- SEPG_CLASS_DB_PROCEDURE,
- SEPG_DB_PROCEDURE__EXECUTE,
- NULL, false) != true)
- {
- pfree(function_label);
+ 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;
- }
- pfree(function_label);
+
return false;
}
if (!stack)
{
MemoryContext oldcxt;
- const char *cur_label = sepgsql_get_client_label();
oldcxt = MemoryContextSwitchTo(flinfo->fn_mcxt);
stack = palloc(sizeof(*stack));
stack->old_label = NULL;
- stack->new_label = sepgsql_proc_get_domtrans(flinfo->fn_oid);
+ stack->new_label = sepgsql_avc_trusted_proc(flinfo->fn_oid);
stack->next_private = 0;
MemoryContextSwitchTo(oldcxt);
- if (strcmp(cur_label, stack->new_label) != 0)
- {
- /*
- * process:transition permission between old and new
- * label, when user tries to switch security label of the
- * client on execution of trusted procedure.
- */
- sepgsql_check_perms(cur_label, stack->new_label,
- SEPG_CLASS_PROCESS,
- SEPG_PROCESS__TRANSITION,
- NULL, true);
- }
+ /*
+ * 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);
- stack->old_label = sepgsql_set_client_label(stack->new_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);
if (next_fmgr_hook)
(*next_fmgr_hook) (event, flinfo, &stack->next_private);
- sepgsql_set_client_label(stack->old_label);
+ if (stack->old_label)
+ sepgsql_set_client_label(stack->old_label);
stack->old_label = NULL;
break;
errmsg("SELinux: failed to get server security label: %m")));
sepgsql_set_client_label(context);
+ /* Initialize userspace access vector cache */
+ sepgsql_avc_init();
+
/* Security label provider hook */
register_label_provider(SEPGSQL_LABEL_TAG,
sepgsql_object_relabel);
void
sepgsql_proc_relabel(Oid functionId, const char *seclabel)
{
- char *scontext = sepgsql_get_client_label();
- char *tcontext;
- char *audit_name;
+ ObjectAddress object;
+ char *audit_name;
- audit_name = getObjectDescriptionOids(ProcedureRelationId, functionId);
+ object.classId = ProcedureRelationId;
+ object.objectId = functionId;
+ object.objectSubId = 0;
+ audit_name = getObjectDescription(&object);
/*
* check db_procedure:{setattr relabelfrom} permission
*/
- tcontext = sepgsql_get_label(ProcedureRelationId, functionId, 0);
- sepgsql_check_perms(scontext,
- tcontext,
- SEPG_CLASS_DB_PROCEDURE,
- SEPG_DB_PROCEDURE__SETATTR |
- SEPG_DB_PROCEDURE__RELABELFROM,
- audit_name,
- true);
- pfree(tcontext);
-
+ sepgsql_avc_check_perms(&object,
+ SEPG_CLASS_DB_PROCEDURE,
+ SEPG_DB_PROCEDURE__SETATTR |
+ SEPG_DB_PROCEDURE__RELABELFROM,
+ audit_name,
+ true);
/*
* check db_procedure:{relabelto} permission
*/
- sepgsql_check_perms(scontext,
- seclabel,
- SEPG_CLASS_DB_PROCEDURE,
- SEPG_DB_PROCEDURE__RELABELTO,
- audit_name,
- true);
+ sepgsql_avc_check_perms_label(seclabel,
+ SEPG_CLASS_DB_PROCEDURE,
+ SEPG_DB_PROCEDURE__RELABELTO,
+ audit_name,
+ true);
pfree(audit_name);
}
-
-/*
- * sepgsql_proc_get_domtrans
- *
- * It computes security label of the client that shall be applied when
- * the current client invokes the supplied function.
- * This computed label is either same or different from the current one.
- * If security policy informed the function is a trusted-procedure,
- * we need to switch security label of the client during execution of
- * the function.
- *
- * Also note that the translated label shall be allocated using palloc().
- * So, need to switch memory context, if you want to hold the string in
- * someone except for CurrentMemoryContext.
- */
-char *
-sepgsql_proc_get_domtrans(Oid functionId)
-{
- char *scontext = sepgsql_get_client_label();
- char *tcontext;
- char *ncontext;
-
- tcontext = sepgsql_get_label(ProcedureRelationId, functionId, 0);
-
- ncontext = sepgsql_compute_create(scontext,
- tcontext,
- SEPG_CLASS_PROCESS);
- pfree(tcontext);
-
- return ncontext;
-}
sepgsql_attribute_relabel(Oid relOid, AttrNumber attnum,
const char *seclabel)
{
- char *scontext = sepgsql_get_client_label();
- char *tcontext;
- char *audit_name;
ObjectAddress object;
+ char *audit_name;
if (get_rel_relkind(relOid) != RELKIND_RELATION)
ereport(ERROR,
/*
* check db_column:{setattr relabelfrom} permission
*/
- tcontext = sepgsql_get_label(RelationRelationId, relOid, attnum);
- sepgsql_check_perms(scontext,
- tcontext,
- SEPG_CLASS_DB_COLUMN,
- SEPG_DB_COLUMN__SETATTR |
- SEPG_DB_COLUMN__RELABELFROM,
- audit_name,
- true);
-
+ sepgsql_avc_check_perms(&object,
+ SEPG_CLASS_DB_COLUMN,
+ SEPG_DB_COLUMN__SETATTR |
+ SEPG_DB_COLUMN__RELABELFROM,
+ audit_name,
+ true);
/*
* check db_column:{relabelto} permission
*/
- sepgsql_check_perms(scontext,
- seclabel,
- SEPG_CLASS_DB_COLUMN,
- SEPG_DB_PROCEDURE__RELABELTO,
- audit_name,
- true);
-
- pfree(tcontext);
+ sepgsql_avc_check_perms_label(seclabel,
+ SEPG_CLASS_DB_COLUMN,
+ SEPG_DB_PROCEDURE__RELABELTO,
+ audit_name,
+ true);
pfree(audit_name);
}
void
sepgsql_relation_relabel(Oid relOid, const char *seclabel)
{
- char *scontext = sepgsql_get_client_label();
- char *tcontext;
+ ObjectAddress object;
char *audit_name;
char relkind;
uint16_t tclass = 0;
errmsg("cannot set security labels on relations except "
"for tables, sequences or views")));
- audit_name = getObjectDescriptionOids(RelationRelationId, relOid);
+ object.classId = RelationRelationId;
+ object.objectId = relOid;
+ object.objectSubId = 0;
+ audit_name = getObjectDescription(&object);
/*
* check db_xxx:{setattr relabelfrom} permission
*/
- tcontext = sepgsql_get_label(RelationRelationId, relOid, 0);
-
- sepgsql_check_perms(scontext,
- tcontext,
- tclass,
- SEPG_DB_TABLE__SETATTR |
- SEPG_DB_TABLE__RELABELFROM,
- audit_name,
- true);
-
+ sepgsql_avc_check_perms(&object,
+ tclass,
+ SEPG_DB_TABLE__SETATTR |
+ SEPG_DB_TABLE__RELABELFROM,
+ audit_name,
+ true);
/*
* check db_xxx:{relabelto} permission
*/
- sepgsql_check_perms(scontext,
- seclabel,
- tclass,
- SEPG_DB_TABLE__RELABELTO,
- audit_name,
- true);
-
- pfree(tcontext);
+ sepgsql_avc_check_perms_label(seclabel,
+ tclass,
+ SEPG_DB_TABLE__RELABELTO,
+ audit_name,
+ true);
pfree(audit_name);
}
void
sepgsql_schema_relabel(Oid namespaceId, const char *seclabel)
{
- char *scontext = sepgsql_get_client_label();
- char *tcontext;
- char *audit_name;
+ ObjectAddress object;
+ char *audit_name;
- audit_name = getObjectDescriptionOids(NamespaceRelationId, namespaceId);
+ object.classId = NamespaceRelationId;
+ object.objectId = namespaceId;
+ object.objectSubId = 0;
+ audit_name = getObjectDescription(&object);
/*
* check db_schema:{setattr relabelfrom} permission
*/
- tcontext = sepgsql_get_label(NamespaceRelationId, namespaceId, 0);
-
- sepgsql_check_perms(scontext,
- tcontext,
- SEPG_CLASS_DB_SCHEMA,
- SEPG_DB_SCHEMA__SETATTR |
- SEPG_DB_SCHEMA__RELABELFROM,
- audit_name,
- true);
-
+ sepgsql_avc_check_perms(&object,
+ SEPG_CLASS_DB_SCHEMA,
+ SEPG_DB_SCHEMA__SETATTR |
+ SEPG_DB_SCHEMA__RELABELFROM,
+ audit_name,
+ true);
/*
* check db_schema:{relabelto} permission
*/
- sepgsql_check_perms(scontext,
- seclabel,
- SEPG_CLASS_DB_SCHEMA,
- SEPG_DB_SCHEMA__RELABELTO,
- audit_name,
- true);
-
- pfree(tcontext);
+ sepgsql_avc_check_perms_label(seclabel,
+ SEPG_CLASS_DB_SCHEMA,
+ SEPG_DB_SCHEMA__RELABELTO,
+ audit_name,
+ true);
pfree(audit_name);
}
sepgsql_getenforce(void)
{
if (sepgsql_mode == SEPGSQL_MODE_DEFAULT &&
- security_getenforce() > 0)
+ selinux_status_getenforce() > 0)
return true;
return false;
#include "fmgr.h"
#include <selinux/selinux.h>
+#include <selinux/avc.h>
/*
* SE-PostgreSQL Label Tag
uint32 required,
const char *audit_name,
bool abort);
+/*
+ * uavc.c
+ */
+#define SEPGSQL_AVC_NOAUDIT ((void *)(-1))
+extern bool sepgsql_avc_check_perms_label(const char *tcontext,
+ uint16 tclass,
+ uint32 required,
+ const char *audit_name,
+ bool abort);
+extern bool sepgsql_avc_check_perms(const ObjectAddress *tobject,
+ uint16 tclass,
+ uint32 required,
+ const char *audit_name,
+ bool abort);
+extern char *sepgsql_avc_trusted_proc(Oid functionId);
+extern void sepgsql_avc_init(void);
/*
* label.c
*/
extern void sepgsql_proc_post_create(Oid functionId);
extern void sepgsql_proc_relabel(Oid functionId, const char *seclabel);
-extern char *sepgsql_proc_get_domtrans(Oid functionId);
#endif /* SEPGSQL_H */
--- /dev/null
+/* -------------------------------------------------------------------------
+ *
+ * contrib/sepgsql/uavc.c
+ *
+ * Implementation of userspace access vector cache; that enables to cache
+ * access control decisions recently used, and reduce number of kernel
+ * invocations to avoid unnecessary performance hit.
+ *
+ * Copyright (c) 2011, PostgreSQL Global Development Group
+ *
+ * -------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include "access/hash.h"
+#include "catalog/pg_proc.h"
+#include "commands/seclabel.h"
+#include "storage/ipc.h"
+#include "utils/guc.h"
+#include "utils/memutils.h"
+
+#include "sepgsql.h"
+
+/*
+ * avc_cache
+ *
+ * It enables to cache access control decision (and behavior on execution of
+ * trusted procedure, db_procedure class only) for a particular pair of
+ * security labels and object class in userspace.
+ */
+typedef struct
+{
+ uint32 hash; /* hash value of this cache entry */
+ char *scontext; /* security context of the subject */
+ char *tcontext; /* security context of the target */
+ uint16 tclass; /* object class of the target */
+
+ uint32 allowed; /* permissions to be allowed */
+ uint32 auditallow; /* permissions to be audited on allowed */
+ uint32 auditdeny; /* permissions to be audited on denied */
+
+ bool permissive; /* true, if permissive rule */
+ bool hot_cache; /* true, if recently referenced */
+ bool tcontext_is_valid;
+ /* true, if tcontext is valid */
+ char *ncontext; /* temporary scontext on execution of trusted
+ * procedure, or NULL elsewhere */
+} avc_cache;
+
+/*
+ * Declaration of static variables
+ */
+#define AVC_NUM_SLOTS 512
+#define AVC_NUM_RECLAIM 16
+#define AVC_DEF_THRESHOLD 384
+
+static MemoryContext avc_mem_cxt;
+static List *avc_slots[AVC_NUM_SLOTS]; /* avc's hash buckets */
+static int avc_num_caches; /* number of caches currently used */
+static int avc_lru_hint; /* index of the buckets to be reclaimed next */
+static int avc_threshold; /* threshold to launch cache-reclaiming */
+static char *avc_unlabeled; /* system 'unlabeled' label */
+
+/*
+ * Hash function
+ */
+static uint32
+sepgsql_avc_hash(const char *scontext, const char *tcontext, uint16 tclass)
+{
+ return hash_any((const unsigned char *)scontext, strlen(scontext))
+ ^ hash_any((const unsigned char *)tcontext, strlen(tcontext))
+ ^ tclass;
+}
+
+/*
+ * Reset all the avc caches
+ */
+static void
+sepgsql_avc_reset(void)
+{
+ MemoryContextReset(avc_mem_cxt);
+
+ memset(avc_slots, 0, sizeof(List *) * AVC_NUM_SLOTS);
+ avc_num_caches = 0;
+ avc_lru_hint = 0;
+ avc_unlabeled = NULL;
+}
+
+/*
+ * Reclaim caches recently unreferenced
+ */
+static void
+sepgsql_avc_reclaim(void)
+{
+ ListCell *cell;
+ ListCell *next;
+ ListCell *prev;
+ int index;
+
+ while (avc_num_caches >= avc_threshold - AVC_NUM_RECLAIM)
+ {
+ index = avc_lru_hint;
+
+ prev = NULL;
+ for (cell = list_head(avc_slots[index]); cell; cell = next)
+ {
+ avc_cache *cache = lfirst(cell);
+
+ next = lnext(cell);
+ if (!cache->hot_cache)
+ {
+ avc_slots[index]
+ = list_delete_cell(avc_slots[index], cell, prev);
+
+ pfree(cache->scontext);
+ pfree(cache->tcontext);
+ if (cache->ncontext)
+ pfree(cache->ncontext);
+ pfree(cache);
+
+ avc_num_caches--;
+ }
+ else
+ {
+ cache->hot_cache = false;
+ prev = cell;
+ }
+ }
+ avc_lru_hint = (avc_lru_hint + 1) % AVC_NUM_SLOTS;
+ }
+}
+
+/*
+ * sepgsql_avc_check_valid
+ *
+ * It checks whether the cached entries are still valid, or not.
+ * If security policy has been reloaded since last reference of access
+ * vector cache, we have to release all the entries, because they are
+ * not valid yet.
+ */
+static bool
+sepgsql_avc_check_valid(void)
+{
+ if (selinux_status_updated() > 0)
+ {
+ sepgsql_avc_reset();
+
+ return false;
+ }
+ return true;
+}
+
+/*
+ * sepgsql_avc_unlabeled
+ *
+ * It returns an alternative label to be applied when no label or invalid
+ * label would be assigned on objects.
+ */
+static char *
+sepgsql_avc_unlabeled(void)
+{
+ if (!avc_unlabeled)
+ {
+ security_context_t unlabeled;
+
+ if (security_get_initial_context_raw("unlabeled", &unlabeled) < 0)
+ ereport(ERROR,
+ (errcode(ERRCODE_INTERNAL_ERROR),
+ errmsg("SELinux: failed to get initial security label: %m")));
+ PG_TRY();
+ {
+ avc_unlabeled = MemoryContextStrdup(avc_mem_cxt, unlabeled);
+ }
+ PG_CATCH();
+ {
+ freecon(unlabeled);
+ PG_RE_THROW();
+ }
+ PG_END_TRY();
+
+ freecon(unlabeled);
+ }
+ return avc_unlabeled;
+}
+
+/*
+ * sepgsql_avc_compute
+ *
+ * A fallback path, when cache mishit. It asks SELinux its access control
+ * decision for the supplied pair of security context and object class.
+ */
+static avc_cache *
+sepgsql_avc_compute(const char *scontext, const char *tcontext, uint16 tclass)
+{
+ char *ucontext = NULL;
+ char *ncontext = NULL;
+ MemoryContext oldctx;
+ avc_cache *cache;
+ uint32 hash;
+ int index;
+ struct av_decision avd;
+
+ hash = sepgsql_avc_hash(scontext, tcontext, tclass);
+ index = hash % AVC_NUM_SLOTS;
+
+ /*
+ * Validation check of the supplied security context.
+ * Because it always invoke system-call, frequent check should be avoided.
+ * Unless security policy is reloaded, validation status shall be kept, so
+ * we also cache whether the supplied security context was valid, or not.
+ */
+ if (security_check_context_raw((security_context_t)tcontext) != 0)
+ ucontext = sepgsql_avc_unlabeled();
+
+ /*
+ * Ask SELinux its access control decision
+ */
+ if (!ucontext)
+ sepgsql_compute_avd(scontext, tcontext, tclass, &avd);
+ else
+ sepgsql_compute_avd(scontext, ucontext, tclass, &avd);
+
+ /*
+ * To boost up trusted procedure checks on db_procedure object
+ * class, we also confirm the decision when user calls a procedure
+ * labeled as 'tcontext'.
+ */
+ if (tclass == SEPG_CLASS_DB_PROCEDURE)
+ {
+ if (!ucontext)
+ ncontext = sepgsql_compute_create(scontext, tcontext,
+ SEPG_CLASS_PROCESS);
+ else
+ ncontext = sepgsql_compute_create(scontext, ucontext,
+ SEPG_CLASS_PROCESS);
+ if (strcmp(scontext, ncontext) == 0)
+ {
+ pfree(ncontext);
+ ncontext = NULL;
+ }
+ }
+
+ /*
+ * Set up an avc_cache object
+ */
+ oldctx = MemoryContextSwitchTo(avc_mem_cxt);
+
+ cache = palloc0(sizeof(avc_cache));
+
+ cache->hash = hash;
+ cache->scontext = pstrdup(scontext);
+ cache->tcontext = pstrdup(tcontext);
+ cache->tclass = tclass;
+
+ cache->allowed = avd.allowed;
+ cache->auditallow = avd.auditallow;
+ cache->auditdeny = avd.auditdeny;
+ cache->hot_cache = true;
+ if (avd.flags & SELINUX_AVD_FLAGS_PERMISSIVE)
+ cache->permissive = true;
+ if (!ucontext)
+ cache->tcontext_is_valid = true;
+ if (ncontext)
+ cache->ncontext = pstrdup(ncontext);
+
+ avc_num_caches++;
+
+ if (avc_num_caches > avc_threshold)
+ sepgsql_avc_reclaim();
+
+ avc_slots[index] = lcons(cache, avc_slots[index]);
+
+ MemoryContextSwitchTo(oldctx);
+
+ return cache;
+}
+
+/*
+ * sepgsql_avc_lookup
+ *
+ * It lookups a cache entry that matches with the supplied object
+ * identifiers and object class. If not found, it tries to create
+ * a new cache entry.
+ */
+static avc_cache *
+sepgsql_avc_lookup(const char *scontext, const char *tcontext, uint16 tclass)
+{
+ avc_cache *cache;
+ ListCell *cell;
+ uint32 hash;
+ int index;
+
+ hash = sepgsql_avc_hash(scontext, tcontext, tclass);
+ index = hash % AVC_NUM_SLOTS;
+
+ foreach (cell, avc_slots[index])
+ {
+ cache = lfirst(cell);
+
+ if (cache->hash == hash &&
+ cache->tclass == tclass &&
+ strcmp(cache->tcontext, tcontext) == 0 &&
+ strcmp(cache->scontext, scontext) == 0)
+ {
+ cache->hot_cache = true;
+ return cache;
+ }
+ }
+ /* not found, so insert a new cache */
+ return sepgsql_avc_compute(scontext, tcontext, tclass);
+}
+
+/*
+ * sepgsql_avc_check_perms(_label)
+ *
+ * It returns 'true', if the security policy suggested to allow the required
+ * permissions. Otherwise, it returns 'false' or raises an error according
+ * to the 'abort' argument.
+ * The 'tobject' and 'tclass' identify the target object being referenced,
+ * and 'required' is a bitmask of permissions (SEPG_*__*) defined for each
+ * object classes.
+ * The 'audit_name' is the object name (optional). If SEPGSQL_AVC_NOAUDIT
+ * was supplied, it means to skip all the audit messages.
+ */
+bool
+sepgsql_avc_check_perms_label(const char *tcontext,
+ uint16 tclass, uint32 required,
+ const char *audit_name, bool abort)
+{
+ char *scontext = sepgsql_get_client_label();
+ avc_cache *cache;
+ uint32 denied;
+ uint32 audited;
+ bool result;
+
+ sepgsql_avc_check_valid();
+ do {
+ result = true;
+
+ /*
+ * If target object is unlabeled, we assume it has
+ * system 'unlabeled' security context instead.
+ */
+ if (tcontext)
+ cache = sepgsql_avc_lookup(scontext, tcontext, tclass);
+ else
+ cache = sepgsql_avc_lookup(scontext,
+ sepgsql_avc_unlabeled(), tclass);
+
+ denied = required & ~cache->allowed;
+
+ /*
+ * Compute permissions to be audited
+ */
+ if (sepgsql_get_debug_audit())
+ audited = (denied ? (denied & ~0) : (required & ~0));
+ else
+ audited = denied ? (denied & cache->auditdeny)
+ : (required & cache->auditallow);
+
+ if (denied)
+ {
+ /*
+ * In permissive mode or permissive domain, violated permissions
+ * shall be audited on the log files at once, and implicitly
+ * allowed them to avoid flood of access denied logs, because
+ * the purpose of permissive mode/domain is to collect violation
+ * log to fix up security policy itself.
+ */
+ if (!sepgsql_getenforce() || cache->permissive)
+ cache->allowed |= required;
+ else
+ result = false;
+ }
+ } while (!sepgsql_avc_check_valid());
+
+ /*
+ * In the case when we have something auditable actions here,
+ * sepgsql_audit_log shall be called with text representation of
+ * security labels for both of subject and object.
+ * It records this access violation, so DBA will be able to find
+ * out unexpected security problems later.
+ */
+ if (audited != 0 &&
+ audit_name != SEPGSQL_AVC_NOAUDIT &&
+ sepgsql_get_mode() != SEPGSQL_MODE_INTERNAL)
+ {
+ sepgsql_audit_log(!!denied,
+ cache->scontext,
+ cache->tcontext_is_valid ?
+ cache->tcontext : sepgsql_avc_unlabeled(),
+ cache->tclass,
+ audited,
+ audit_name);
+ }
+
+ if (abort && !result)
+ ereport(ERROR,
+ (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
+ errmsg("SELinux: security policy violation")));
+
+ return result;
+}
+
+bool
+sepgsql_avc_check_perms(const ObjectAddress *tobject,
+ uint16 tclass, uint32 required,
+ const char *audit_name, bool abort)
+{
+ char *tcontext = GetSecurityLabel(tobject, SEPGSQL_LABEL_TAG);
+ bool rc;
+
+ rc = sepgsql_avc_check_perms_label(tcontext,
+ tclass, required,
+ audit_name, abort);
+ if (tcontext)
+ pfree(tcontext);
+
+ return rc;
+}
+
+/*
+ * sepgsql_avc_trusted_proc
+ *
+ * It returns a security label to be switched on execution of the supplied
+ * procedure, if it was configured as a trusted procedure. Otherwise, NULL
+ * shall be returned.
+ */
+char *
+sepgsql_avc_trusted_proc(Oid functionId)
+{
+ char *scontext = sepgsql_get_client_label();
+ char *tcontext;
+ ObjectAddress tobject;
+ avc_cache *cache;
+
+ tobject.classId = ProcedureRelationId;
+ tobject.objectId = functionId;
+ tobject.objectSubId = 0;
+ tcontext = GetSecurityLabel(&tobject, SEPGSQL_LABEL_TAG);
+
+ sepgsql_avc_check_valid();
+ do {
+ if (tcontext)
+ cache = sepgsql_avc_lookup(scontext, tcontext,
+ SEPG_CLASS_DB_PROCEDURE);
+ else
+ cache = sepgsql_avc_lookup(scontext, sepgsql_avc_unlabeled(),
+ SEPG_CLASS_DB_PROCEDURE);
+ } while (!sepgsql_avc_check_valid());
+
+ return cache->ncontext;
+}
+
+/*
+ * sepgsql_avc_exit
+ *
+ * It clean up userspace avc stuff on process exit
+ */
+static void
+sepgsql_avc_exit(int code, Datum arg)
+{
+ selinux_status_close();
+}
+
+/*
+ * sepgsql_avc_init
+ *
+ * It shall be invoked at once from _PG_init routine to initialize
+ * userspace access vector cache stuff.
+ */
+void
+sepgsql_avc_init(void)
+{
+ int rc;
+
+ /*
+ * All the avc stuff shall be allocated on avc_mem_cxt
+ */
+ avc_mem_cxt = AllocSetContextCreate(TopMemoryContext,
+ "userspace access vector cache",
+ ALLOCSET_DEFAULT_MINSIZE,
+ ALLOCSET_DEFAULT_INITSIZE,
+ ALLOCSET_DEFAULT_MAXSIZE);
+ memset(avc_slots, 0, sizeof(avc_slots));
+ avc_num_caches = 0;
+ avc_lru_hint = 0;
+ avc_threshold = AVC_DEF_THRESHOLD;
+
+ /*
+ * SELinux allows to mmap(2) its kernel status page in read-only mode
+ * to inform userspace applications its status updating (such as
+ * policy reloading) without system-call invocations.
+ * This feature is only supported in Linux-2.6.38 or later, however,
+ * libselinux provides a fallback mode to know its status using
+ * netlink sockets.
+ */
+ rc = selinux_status_open(1);
+ if (rc < 0)
+ ereport(ERROR,
+ (errcode(ERRCODE_INTERNAL_ERROR),
+ errmsg("SELinux: could not open selinux status : %m")));
+ else if (rc > 0)
+ ereport(LOG,
+ (errmsg("SELinux: kernel status page uses fallback mode")));
+
+ /*
+ * To close selinux status page on process exit
+ */
+ on_proc_exit(sepgsql_avc_exit, 0);
+}
or higher with <productname>SELinux</productname> enabled. It is not
available on any other platform, and must be explicitly enabled using
<literal>--with-selinux</>. You will also need <productname>libselinux</>
- 2.0.9
3 or higher and <productname>selinux-policy</> 3.9.13 or higher
+ 2.0.9
9 or higher and <productname>selinux-policy</> 3.9.13 or higher
(some distributions may backport the necessary rules into older policy
versions).
</para>
<title>Limitations</title>
<variablelist>
- <varlistentry>
- <term>Userspace access vector cache</term>
- <listitem>
- <para>
- <productname>sepgsql</> does not yet support an access vector cache.
- This would likely improve performance.
- </para>
- </listitem>
- </varlistentry>
-
<varlistentry>
<term>Data Definition Language (DDL) Permissions</term>
<listitem>
projects / postgresql / commitdiff