diff --git a/configure b/configure index 039d5f863330b1adf6c3bc0817228d0c45f49a52..31bc8fb374bb01ec5ac417c0afb7bea42316ae6a 100755 --- a/configure +++ b/configure @@ -9481,9 +9481,9 @@ fi # 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 @@ -9501,11 +9501,11 @@ cat >>conftest.$ac_ext <<_ACEOF #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; } @@ -9531,12 +9531,12 @@ $as_echo "$ac_try_echo") >&5 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.$ac_ext >&5 - ac_cv_lib_selinux_selinux_sepgsql_context_path=no + ac_cv_lib_selinux_selinux_status_open=no fi rm -rf conftest.dSYM @@ -9544,9 +9544,9 @@ rm -f core conftest.err conftest.$ac_objext conftest_ipa8_conftest.oo \ 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 @@ -9554,8 +9554,8 @@ _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 "$as_me: error: library 'libselinux', version 2.0.99 or newer, is required for SELinux support" >&2;} { (exit 1); exit 1; }; } fi diff --git a/configure.in b/configure.in index 15a206b092f1f7947d0f576dd94233907a40bf20..05259cb86942bec684641716534f7fcb2ab87b9b 100644 --- a/configure.in +++ b/configure.in @@ -964,8 +964,8 @@ fi # for contrib/sepgsql if test "$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 diff --git a/contrib/sepgsql/Makefile b/contrib/sepgsql/Makefile index 248b1dd7f401c3b5972b0720210292e92d9bda06..c83b2e3cef80d826b83d41c37aa7d905a050037c 100644 --- a/contrib/sepgsql/Makefile +++ b/contrib/sepgsql/Makefile @@ -1,7 +1,7 @@ # 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 diff --git a/contrib/sepgsql/dml.c b/contrib/sepgsql/dml.c index 22666b708e96912b2701cb895c21db1de07d1c86..319933747c835da25bff088b8e332f5179f668ca 100644 --- a/contrib/sepgsql/dml.c +++ b/contrib/sepgsql/dml.c @@ -150,12 +150,11 @@ check_relation_privileges(Oid relOid, 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; /* @@ -184,45 +183,43 @@ check_relation_privileges(Oid relOid, /* * 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); /* @@ -242,7 +239,6 @@ check_relation_privileges(Oid relOid, { AttrNumber attnum; uint32 column_perms = 0; - ObjectAddress object; if (bms_is_member(index, selected)) column_perms |= SEPG_DB_COLUMN__SELECT; @@ -258,20 +254,17 @@ check_relation_privileges(Oid relOid, /* 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) diff --git a/contrib/sepgsql/hooks.c b/contrib/sepgsql/hooks.c index 7797ccb199f088ed101b0c77b41d0b9f98a63d2d..ca6ce99808001cc74925f9033e466a103802fb0d 100644 --- a/contrib/sepgsql/hooks.c +++ b/contrib/sepgsql/hooks.c @@ -184,9 +184,7 @@ sepgsql_exec_check_perms(List *rangeTabls, bool abort) 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)) @@ -198,14 +196,8 @@ sepgsql_needs_fmgr_hook(Oid 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 @@ -213,17 +205,15 @@ sepgsql_needs_fmgr_hook(Oid functionId) * 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; } @@ -251,33 +241,31 @@ sepgsql_fmgr_hook(FmgrHookEventType event, 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); @@ -290,7 +278,8 @@ sepgsql_fmgr_hook(FmgrHookEventType event, 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; @@ -433,6 +422,9 @@ _PG_init(void) 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); diff --git a/contrib/sepgsql/proc.c b/contrib/sepgsql/proc.c index 3b8bf23ba393cfe77bb956b2662c6698a9598aa3..9630d456896ad97aab15bb43acb5960051950b1f 100644 --- a/contrib/sepgsql/proc.c +++ b/contrib/sepgsql/proc.c @@ -96,64 +96,30 @@ sepgsql_proc_post_create(Oid functionId) 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; -} diff --git a/contrib/sepgsql/relation.c b/contrib/sepgsql/relation.c index 963cfdf9f10c7ba9845f7a1f3a0eb0538791b910..07673825e5d335e89773d590058cfdaa5c262c8a 100644 --- a/contrib/sepgsql/relation.c +++ b/contrib/sepgsql/relation.c @@ -79,10 +79,8 @@ void 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, @@ -97,26 +95,20 @@ sepgsql_attribute_relabel(Oid relOid, AttrNumber attnum, /* * 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); } @@ -227,8 +219,7 @@ out: 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; @@ -246,31 +237,27 @@ sepgsql_relation_relabel(Oid relOid, const char *seclabel) 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); } diff --git a/contrib/sepgsql/schema.c b/contrib/sepgsql/schema.c index 0de89971fbc15c879e7bbac765ebd26dea62460b..aae68ef964bc2867aee45e0ebd5fcf2bb212a4c2 100644 --- a/contrib/sepgsql/schema.c +++ b/contrib/sepgsql/schema.c @@ -65,35 +65,30 @@ sepgsql_schema_post_create(Oid namespaceId) 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); } diff --git a/contrib/sepgsql/selinux.c b/contrib/sepgsql/selinux.c index 1f5a97e878ab1d67bd66a5a02500a6c1ecb3c989..d693d63ed0e844bab4daa362a1ea4b4036f91ac8 100644 --- a/contrib/sepgsql/selinux.c +++ b/contrib/sepgsql/selinux.c @@ -642,7 +642,7 @@ bool sepgsql_getenforce(void) { if (sepgsql_mode == SEPGSQL_MODE_DEFAULT && - security_getenforce() > 0) + selinux_status_getenforce() > 0) return true; return false; diff --git a/contrib/sepgsql/sepgsql.h b/contrib/sepgsql/sepgsql.h index 71688ab784f7fba46c882b5a3f701937eb6b7d1e..35b500c3ffa8a4d7b067e45cfebfd61ab05f373f 100644 --- a/contrib/sepgsql/sepgsql.h +++ b/contrib/sepgsql/sepgsql.h @@ -15,6 +15,7 @@ #include "fmgr.h" #include <selinux/selinux.h> +#include <selinux/avc.h> /* * SE-PostgreSQL Label Tag @@ -245,6 +246,22 @@ extern bool sepgsql_check_perms(const char *scontext, 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 @@ -286,6 +303,5 @@ extern void sepgsql_relation_relabel(Oid relOid, const char *seclabel); */ 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 */ diff --git a/contrib/sepgsql/uavc.c b/contrib/sepgsql/uavc.c new file mode 100644 index 0000000000000000000000000000000000000000..bcf0d4cd1cf97bb25a3e909f207c7779a0f24392 --- /dev/null +++ b/contrib/sepgsql/uavc.c @@ -0,0 +1,511 @@ +/* ------------------------------------------------------------------------- + * + * 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); +} diff --git a/doc/src/sgml/sepgsql.sgml b/doc/src/sgml/sepgsql.sgml index fc379885d8b0389923984b17ef1b59b8fe743393..0a02edb624a490ff356ded38358eb9924bee06d2 100644 --- a/doc/src/sgml/sepgsql.sgml +++ b/doc/src/sgml/sepgsql.sgml @@ -64,7 +64,7 @@ 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</> - 2.0.93 or higher and <productname>selinux-policy</> 3.9.13 or higher + 2.0.99 or higher and <productname>selinux-policy</> 3.9.13 or higher (some distributions may backport the necessary rules into older policy versions). </para> @@ -473,16 +473,6 @@ postgres=# SELECT cid, cname, show_credit(cid) FROM customer; <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>