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postgresql/contrib/sepgsql/label.c
Tom Lane 1cff1b95ab Represent Lists as expansible arrays, not chains of cons-cells. 
Originally, Postgres Lists were a more or less exact reimplementation of
Lisp lists, which consist of chains of separately-allocated cons cells,
each having a value and a next-cell link.  We'd hacked that once before
(commit d0b4399d8) to add a separate List header, but the data was still
in cons cells.  That makes some operations -- notably list_nth() -- O(N),
and it's bulky because of the next-cell pointers and per-cell palloc
overhead, and it's very cache-unfriendly if the cons cells end up
scattered around rather than being adjacent.

In this rewrite, we still have List headers, but the data is in a
resizable array of values, with no next-cell links.  Now we need at
most two palloc's per List, and often only one, since we can allocate
some values in the same palloc call as the List header.  (Of course,
extending an existing List may require repalloc's to enlarge the array.
But this involves just O(log N) allocations not O(N).)

Of course this is not without downsides.  The key difficulty is that
addition or deletion of a list entry may now cause other entries to
move, which it did not before.

For example, that breaks foreach() and sister macros, which historically
used a pointer to the current cons-cell as loop state.  We can repair
those macros transparently by making their actual loop state be an
integer list index; the exposed "ListCell *" pointer is no longer state
carried across loop iterations, but is just a derived value.  (In
practice, modern compilers can optimize things back to having just one
loop state value, at least for simple cases with inline loop bodies.)
In principle, this is a semantics change for cases where the loop body
inserts or deletes list entries ahead of the current loop index; but
I found no such cases in the Postgres code.

The change is not at all transparent for code that doesn't use foreach()
but chases lists "by hand" using lnext().  The largest share of such
code in the backend is in loops that were maintaining "prev" and "next"
variables in addition to the current-cell pointer, in order to delete
list cells efficiently using list_delete_cell().  However, we no longer
need a previous-cell pointer to delete a list cell efficiently.  Keeping
a next-cell pointer doesn't work, as explained above, but we can improve
matters by changing such code to use a regular foreach() loop and then
using the new macro foreach_delete_current() to delete the current cell.
(This macro knows how to update the associated foreach loop's state so
that no cells will be missed in the traversal.)

There remains a nontrivial risk of code assuming that a ListCell *
pointer will remain good over an operation that could now move the list
contents.  To help catch such errors, list.c can be compiled with a new
define symbol DEBUG_LIST_MEMORY_USAGE that forcibly moves list contents
whenever that could possibly happen.  This makes list operations
significantly more expensive so it's not normally turned on (though it
is on by default if USE_VALGRIND is on).

There are two notable API differences from the previous code:

* lnext() now requires the List's header pointer in addition to the
current cell's address.

* list_delete_cell() no longer requires a previous-cell argument.

These changes are somewhat unfortunate, but on the other hand code using
either function needs inspection to see if it is assuming anything
it shouldn't, so it's not all bad.

Programmers should be aware of these significant performance changes:

* list_nth() and related functions are now O(1); so there's no
major access-speed difference between a list and an array.

* Inserting or deleting a list element now takes time proportional to
the distance to the end of the list, due to moving the array elements.
(However, it typically *doesn't* require palloc or pfree, so except in
long lists it's probably still faster than before.)  Notably, lcons()
used to be about the same cost as lappend(), but that's no longer true
if the list is long.  Code that uses lcons() and list_delete_first()
to maintain a stack might usefully be rewritten to push and pop at the
end of the list rather than the beginning.

* There are now list_insert_nth...() and list_delete_nth...() functions
that add or remove a list cell identified by index.  These have the
data-movement penalty explained above, but there's no search penalty.

* list_concat() and variants now copy the second list's data into
storage belonging to the first list, so there is no longer any
sharing of cells between the input lists.  The second argument is
now declared "const List *" to reflect that it isn't changed.

This patch just does the minimum needed to get the new implementation
in place and fix bugs exposed by the regression tests.  As suggested
by the foregoing, there's a fair amount of followup work remaining to
do.

Also, the ENABLE_LIST_COMPAT macros are finally removed in this
commit.  Code using those should have been gone a dozen years ago.

Patch by me; thanks to David Rowley, Jesper Pedersen, and others
for review.

Discussion: https://postgr.es/m/11587.1550975080@sss.pgh.pa.us
2019-07-15 13:41:58 -04:00

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/* -------------------------------------------------------------------------
*
* contrib/sepgsql/label.c
*
* Routines to support SELinux labels (security context)
*
* Copyright (c) 2010-2019, PostgreSQL Global Development Group
*
* -------------------------------------------------------------------------
*/
#include "postgres.h"
#include <selinux/label.h>
#include "access/htup_details.h"
#include "access/genam.h"
#include "access/table.h"
#include "access/xact.h"
#include "catalog/catalog.h"
#include "catalog/dependency.h"
#include "catalog/indexing.h"
#include "catalog/pg_attribute.h"
#include "catalog/pg_class.h"
#include "catalog/pg_database.h"
#include "catalog/pg_namespace.h"
#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 "utils/fmgroids.h"
#include "utils/guc.h"
#include "utils/lsyscache.h"
#include "utils/memutils.h"
#include "utils/rel.h"
#include "sepgsql.h"
/*
* 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_*
*
* security label of the database client. Initially the client security label
* is equal to client_label_peer, and can be changed by one or more calls to
* sepgsql_setcon(), and also be temporarily overridden during execution of a
* trusted-procedure.
*
* sepgsql_setcon() is a transaction-aware operation; a (sub-)transaction
* rollback should also rollback the current client security label. Therefore
* we use the list client_label_pending of pending_label to keep track of which
* labels were set during the (sub-)transactions.
*/
static char *client_label_peer = NULL; /* set by getpeercon(3) */
static List *client_label_pending = NIL; /* pending list being set by
* sepgsql_setcon() */
static char *client_label_committed = NULL; /* set by sepgsql_setcon(), and
* already committed */
static char *client_label_func = NULL; /* set by trusted procedure */
typedef struct
{
SubTransactionId subid;
char *label;
} pending_label;
/*
* sepgsql_get_client_label
*
* Returns the current security label of the client. All code should use this
* routine to get the current label, instead of referring to the client_label_*
* variables above.
*/
char *
sepgsql_get_client_label(void)
{
/* trusted procedure client label override */
if (client_label_func)
return client_label_func;
/* uncommitted sepgsql_setcon() value */
if (client_label_pending)
{
pending_label *plabel = llast(client_label_pending);
if (plabel->label)
return plabel->label;
}
else if (client_label_committed)
return client_label_committed; /* set by sepgsql_setcon() committed */
/* default label */
Assert(client_label_peer != NULL);
return client_label_peer;
}
/*
* sepgsql_set_client_label
*
* This routine tries to switch the current security label of the client, and
* checks related permissions. The supplied new label shall be added to the
* client_label_pending list, then saved at transaction-commit time to ensure
* transaction-awareness.
*/
static void
sepgsql_set_client_label(const char *new_label)
{
const char *tcontext;
MemoryContext oldcxt;
pending_label *plabel;
/* Reset to the initial client label, if NULL */
if (!new_label)
tcontext = client_label_peer;
else
{
if (security_check_context_raw((security_context_t) new_label) < 0)
ereport(ERROR,
(errcode(ERRCODE_INVALID_NAME),
errmsg("SELinux: invalid security label: \"%s\"",
new_label)));
tcontext = new_label;
}
/* Check process:{setcurrent} permission. */
sepgsql_avc_check_perms_label(sepgsql_get_client_label(),
SEPG_CLASS_PROCESS,
SEPG_PROCESS__SETCURRENT,
NULL,
true);
/* Check process:{dyntransition} permission. */
sepgsql_avc_check_perms_label(tcontext,
SEPG_CLASS_PROCESS,
SEPG_PROCESS__DYNTRANSITION,
NULL,
true);
/*
* Append the supplied new_label on the pending list until the current
* transaction is committed.
*/
oldcxt = MemoryContextSwitchTo(CurTransactionContext);
plabel = palloc0(sizeof(pending_label));
plabel->subid = GetCurrentSubTransactionId();
if (new_label)
plabel->label = pstrdup(new_label);
client_label_pending = lappend(client_label_pending, plabel);
MemoryContextSwitchTo(oldcxt);
}
/*
* sepgsql_xact_callback
*
* A callback routine of transaction commit/abort/prepare. Commit or abort
* changes in the client_label_pending list.
*/
static void
sepgsql_xact_callback(XactEvent event, void *arg)
{
if (event == XACT_EVENT_COMMIT)
{
if (client_label_pending != NIL)
{
pending_label *plabel = llast(client_label_pending);
char *new_label;
if (plabel->label)
new_label = MemoryContextStrdup(TopMemoryContext,
plabel->label);
else
new_label = NULL;
if (client_label_committed)
pfree(client_label_committed);
client_label_committed = new_label;
/*
* XXX - Note that items of client_label_pending are allocated on
* CurTransactionContext, thus, all acquired memory region shall
* be released implicitly.
*/
client_label_pending = NIL;
}
}
else if (event == XACT_EVENT_ABORT)
client_label_pending = NIL;
}
/*
* sepgsql_subxact_callback
*
* A callback routine of sub-transaction start/abort/commit. Releases all
* security labels that are set within the sub-transaction that is aborted.
*/
static void
sepgsql_subxact_callback(SubXactEvent event, SubTransactionId mySubid,
SubTransactionId parentSubid, void *arg)
{
ListCell *cell;
if (event == SUBXACT_EVENT_ABORT_SUB)
{
foreach(cell, client_label_pending)
{
pending_label *plabel = lfirst(cell);
if (plabel->subid == mySubid)
client_label_pending
= foreach_delete_current(client_label_pending, cell);
}
}
}
/*
* 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_peer) < 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)
{
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 |
SEPG_DB_PROCEDURE__ENTRYPOINT,
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.
*
* Also, db_procedure:entrypoint permission should be checked
* whether this procedure can perform as an entrypoint of the
* trusted procedure, or not. Note that db_procedure:execute
* permission shall be checked individually.
*/
if (stack->new_label)
{
ObjectAddress object;
object.classId = ProcedureRelationId;
object.objectId = flinfo->fn_oid;
object.objectSubId = 0;
sepgsql_avc_check_perms(&object,
SEPG_CLASS_DB_PROCEDURE,
SEPG_DB_PROCEDURE__ENTRYPOINT,
getObjectDescription(&object),
true);
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_func;
client_label_func = 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_func = stack->old_label;
stack->old_label = NULL;
}
break;
default:
elog(ERROR, "unexpected event type: %d", (int) event);
break;
}
}
/*
* sepgsql_init_client_label
*
* Initializes the client security label and sets up related hooks for client
* label management.
*/
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_peer) < 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;
/* 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;
/* Transaction/Sub-transaction callbacks */
RegisterXactCallback(sepgsql_xact_callback, NULL);
RegisterSubXactCallback(sepgsql_subxact_callback, NULL);
}
/*
* sepgsql_get_label
*
* It returns a security context of the specified database object.
* If unlabeled or incorrectly labeled, the system "unlabeled" label
* shall be returned.
*/
char *
sepgsql_get_label(Oid classId, Oid objectId, int32 subId)
{
ObjectAddress object;
char *label;
object.classId = classId;
object.objectId = objectId;
object.objectSubId = subId;
label = GetSecurityLabel(&object, SEPGSQL_LABEL_TAG);
if (!label || security_check_context_raw((security_context_t) label))
{
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();
{
label = pstrdup(unlabeled);
}
PG_CATCH();
{
freecon(unlabeled);
PG_RE_THROW();
}
PG_END_TRY();
freecon(unlabeled);
}
return label;
}
/*
* sepgsql_object_relabel
*
* An entrypoint of SECURITY LABEL statement
*/
void
sepgsql_object_relabel(const ObjectAddress *object, const char *seclabel)
{
/*
* validate format of the supplied security label, if it is security
* context of selinux.
*/
if (seclabel &&
security_check_context_raw((security_context_t) seclabel) < 0)
ereport(ERROR,
(errcode(ERRCODE_INVALID_NAME),
errmsg("SELinux: invalid security label: \"%s\"", seclabel)));
/*
* Do actual permission checks for each object classes
*/
switch (object->classId)
{
case DatabaseRelationId:
sepgsql_database_relabel(object->objectId, seclabel);
break;
case NamespaceRelationId:
sepgsql_schema_relabel(object->objectId, seclabel);
break;
case RelationRelationId:
if (object->objectSubId == 0)
sepgsql_relation_relabel(object->objectId,
seclabel);
else
sepgsql_attribute_relabel(object->objectId,
object->objectSubId,
seclabel);
break;
case ProcedureRelationId:
sepgsql_proc_relabel(object->objectId, seclabel);
break;
default:
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("sepgsql provider does not support labels on %s",
getObjectTypeDescription(object))));
break;
}
}
/*
* TEXT sepgsql_getcon(VOID)
*
* It returns the security label of the client.
*/
PG_FUNCTION_INFO_V1(sepgsql_getcon);
Datum
sepgsql_getcon(PG_FUNCTION_ARGS)
{
char *client_label;
if (!sepgsql_is_enabled())
PG_RETURN_NULL();
client_label = sepgsql_get_client_label();
PG_RETURN_TEXT_P(cstring_to_text(client_label));
}
/*
* BOOL sepgsql_setcon(TEXT)
*
* It switches the security label of the client.
*/
PG_FUNCTION_INFO_V1(sepgsql_setcon);
Datum
sepgsql_setcon(PG_FUNCTION_ARGS)
{
const char *new_label;
if (PG_ARGISNULL(0))
new_label = NULL;
else
new_label = TextDatumGetCString(PG_GETARG_DATUM(0));
sepgsql_set_client_label(new_label);
PG_RETURN_BOOL(true);
}
/*
* TEXT sepgsql_mcstrans_in(TEXT)
*
* It translate the given qualified MLS/MCS range into raw format
* when mcstrans daemon is working.
*/
PG_FUNCTION_INFO_V1(sepgsql_mcstrans_in);
Datum
sepgsql_mcstrans_in(PG_FUNCTION_ARGS)
{
text *label = PG_GETARG_TEXT_PP(0);
char *raw_label;
char *result;
if (!sepgsql_is_enabled())
ereport(ERROR,
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("sepgsql is not enabled")));
if (selinux_trans_to_raw_context(text_to_cstring(label),
&raw_label) < 0)
ereport(ERROR,
(errcode(ERRCODE_INTERNAL_ERROR),
errmsg("SELinux: could not translate security label: %m")));
PG_TRY();
{
result = pstrdup(raw_label);
}
PG_CATCH();
{
freecon(raw_label);
PG_RE_THROW();
}
PG_END_TRY();
freecon(raw_label);
PG_RETURN_TEXT_P(cstring_to_text(result));
}
/*
* TEXT sepgsql_mcstrans_out(TEXT)
*
* It translate the given raw MLS/MCS range into qualified format
* when mcstrans daemon is working.
*/
PG_FUNCTION_INFO_V1(sepgsql_mcstrans_out);
Datum
sepgsql_mcstrans_out(PG_FUNCTION_ARGS)
{
text *label = PG_GETARG_TEXT_PP(0);
char *qual_label;
char *result;
if (!sepgsql_is_enabled())
ereport(ERROR,
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("sepgsql is not currently enabled")));
if (selinux_raw_to_trans_context(text_to_cstring(label),
&qual_label) < 0)
ereport(ERROR,
(errcode(ERRCODE_INTERNAL_ERROR),
errmsg("SELinux: could not translate security label: %m")));
PG_TRY();
{
result = pstrdup(qual_label);
}
PG_CATCH();
{
freecon(qual_label);
PG_RE_THROW();
}
PG_END_TRY();
freecon(qual_label);
PG_RETURN_TEXT_P(cstring_to_text(result));
}
/*
* quote_object_names
*
* It tries to quote the supplied identifiers
*/
static char *
quote_object_name(const char *src1, const char *src2,
const char *src3, const char *src4)
{
StringInfoData result;
const char *temp;
initStringInfo(&result);
if (src1)
{
temp = quote_identifier(src1);
appendStringInfoString(&result, temp);
if (src1 != temp)
pfree((void *) temp);
}
if (src2)
{
temp = quote_identifier(src2);
appendStringInfo(&result, ".%s", temp);
if (src2 != temp)
pfree((void *) temp);
}
if (src3)
{
temp = quote_identifier(src3);
appendStringInfo(&result, ".%s", temp);
if (src3 != temp)
pfree((void *) temp);
}
if (src4)
{
temp = quote_identifier(src4);
appendStringInfo(&result, ".%s", temp);
if (src4 != temp)
pfree((void *) temp);
}
return result.data;
}
/*
* exec_object_restorecon
*
* This routine is a helper called by sepgsql_restorecon; it set up
* initial security labels of database objects within the supplied
* catalog OID.
*/
static void
exec_object_restorecon(struct selabel_handle *sehnd, Oid catalogId)
{
Relation rel;
SysScanDesc sscan;
HeapTuple tuple;
char *database_name = get_database_name(MyDatabaseId);
char *namespace_name;
Oid namespace_id;
char *relation_name;
/*
* Open the target catalog. We don't want to allow writable accesses by
* other session during initial labeling.
*/
rel = table_open(catalogId, AccessShareLock);
sscan = systable_beginscan(rel, InvalidOid, false,
NULL, 0, NULL);
while (HeapTupleIsValid(tuple = systable_getnext(sscan)))
{
Form_pg_database datForm;
Form_pg_namespace nspForm;
Form_pg_class relForm;
Form_pg_attribute attForm;
Form_pg_proc proForm;
char *objname;
int objtype = 1234;
ObjectAddress object;
security_context_t context;
/*
* The way to determine object name depends on object classes. So, any
* branches set up `objtype', `objname' and `object' here.
*/
switch (catalogId)
{
case DatabaseRelationId:
datForm = (Form_pg_database) GETSTRUCT(tuple);
objtype = SELABEL_DB_DATABASE;
objname = quote_object_name(NameStr(datForm->datname),
NULL, NULL, NULL);
object.classId = DatabaseRelationId;
object.objectId = datForm->oid;
object.objectSubId = 0;
break;
case NamespaceRelationId:
nspForm = (Form_pg_namespace) GETSTRUCT(tuple);
objtype = SELABEL_DB_SCHEMA;
objname = quote_object_name(database_name,
NameStr(nspForm->nspname),
NULL, NULL);
object.classId = NamespaceRelationId;
object.objectId = nspForm->oid;
object.objectSubId = 0;
break;
case RelationRelationId:
relForm = (Form_pg_class) GETSTRUCT(tuple);
if (relForm->relkind == RELKIND_RELATION ||
relForm->relkind == RELKIND_PARTITIONED_TABLE)
objtype = SELABEL_DB_TABLE;
else if (relForm->relkind == RELKIND_SEQUENCE)
objtype = SELABEL_DB_SEQUENCE;
else if (relForm->relkind == RELKIND_VIEW)
objtype = SELABEL_DB_VIEW;
else
continue; /* no need to assign security label */
namespace_name = get_namespace_name(relForm->relnamespace);
objname = quote_object_name(database_name,
namespace_name,
NameStr(relForm->relname),
NULL);
pfree(namespace_name);
object.classId = RelationRelationId;
object.objectId = relForm->oid;
object.objectSubId = 0;
break;
case AttributeRelationId:
attForm = (Form_pg_attribute) GETSTRUCT(tuple);
if (get_rel_relkind(attForm->attrelid) != RELKIND_RELATION &&
get_rel_relkind(attForm->attrelid) != RELKIND_PARTITIONED_TABLE)
continue; /* no need to assign security label */
objtype = SELABEL_DB_COLUMN;
namespace_id = get_rel_namespace(attForm->attrelid);
namespace_name = get_namespace_name(namespace_id);
relation_name = get_rel_name(attForm->attrelid);
objname = quote_object_name(database_name,
namespace_name,
relation_name,
NameStr(attForm->attname));
pfree(namespace_name);
pfree(relation_name);
object.classId = RelationRelationId;
object.objectId = attForm->attrelid;
object.objectSubId = attForm->attnum;
break;
case ProcedureRelationId:
proForm = (Form_pg_proc) GETSTRUCT(tuple);
objtype = SELABEL_DB_PROCEDURE;
namespace_name = get_namespace_name(proForm->pronamespace);
objname = quote_object_name(database_name,
namespace_name,
NameStr(proForm->proname),
NULL);
pfree(namespace_name);
object.classId = ProcedureRelationId;
object.objectId = proForm->oid;
object.objectSubId = 0;
break;
default:
elog(ERROR, "unexpected catalog id: %u", catalogId);
objname = NULL; /* for compiler quiet */
break;
}
if (selabel_lookup_raw(sehnd, &context, objname, objtype) == 0)
{
PG_TRY();
{
/*
* Check SELinux permission to relabel the fetched object,
* then do the actual relabeling.
*/
sepgsql_object_relabel(&object, context);
SetSecurityLabel(&object, SEPGSQL_LABEL_TAG, context);
}
PG_CATCH();
{
freecon(context);
PG_RE_THROW();
}
PG_END_TRY();
freecon(context);
}
else if (errno == ENOENT)
ereport(WARNING,
(errmsg("SELinux: no initial label assigned for %s (type=%d), skipping",
objname, objtype)));
else
ereport(ERROR,
(errcode(ERRCODE_INTERNAL_ERROR),
errmsg("SELinux: could not determine initial security label for %s (type=%d): %m", objname, objtype)));
pfree(objname);
}
systable_endscan(sscan);
table_close(rel, NoLock);
}
/*
* BOOL sepgsql_restorecon(TEXT specfile)
*
* This function tries to assign initial security labels on all the object
* within the current database, according to the system setting.
* It is typically invoked by sepgsql-install script just after initdb, to
* assign initial security labels.
*
* If @specfile is not NULL, it uses explicitly specified specfile, instead
* of the system default.
*/
PG_FUNCTION_INFO_V1(sepgsql_restorecon);
Datum
sepgsql_restorecon(PG_FUNCTION_ARGS)
{
struct selabel_handle *sehnd;
struct selinux_opt seopts;
/*
* SELinux has to be enabled on the running platform.
*/
if (!sepgsql_is_enabled())
ereport(ERROR,
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("sepgsql is not currently enabled")));
/*
* Check DAC permission. Only superuser can set up initial security
* labels, like root-user in filesystems
*/
if (!superuser())
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("SELinux: must be superuser to restore initial contexts")));
/*
* Open selabel_lookup(3) stuff. It provides a set of mapping between an
* initial security label and object class/name due to the system setting.
*/
if (PG_ARGISNULL(0))
{
seopts.type = SELABEL_OPT_UNUSED;
seopts.value = NULL;
}
else
{
seopts.type = SELABEL_OPT_PATH;
seopts.value = TextDatumGetCString(PG_GETARG_DATUM(0));
}
sehnd = selabel_open(SELABEL_CTX_DB, &seopts, 1);
if (!sehnd)
ereport(ERROR,
(errcode(ERRCODE_INTERNAL_ERROR),
errmsg("SELinux: failed to initialize labeling handle: %m")));
PG_TRY();
{
exec_object_restorecon(sehnd, DatabaseRelationId);
exec_object_restorecon(sehnd, NamespaceRelationId);
exec_object_restorecon(sehnd, RelationRelationId);
exec_object_restorecon(sehnd, AttributeRelationId);
exec_object_restorecon(sehnd, ProcedureRelationId);
}
PG_CATCH();
{
selabel_close(sehnd);
PG_RE_THROW();
}
PG_END_TRY();
selabel_close(sehnd);
PG_RETURN_BOOL(true);
}
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