Make REPLICATION privilege checks test current user not authenticated user.

The pg_start_backup() and pg_stop_backup() functions checked the privileges
of the initially-authenticated user rather than the current user, which is
wrong.  For example, a user-defined index function could successfully call
these functions when executed by ANALYZE within autovacuum.  This could
allow an attacker with valid but low-privilege database access to interfere
with creation of routine backups.  Reported and fixed by Noah Misch.

Security: CVE-2013-1901

4 files changed, 7 insertions, 7 deletions

diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 859df783e6b..4c96afa0f3c 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -8982,7 +8982,7 @@ do_pg_start_backup(const char *backupidstr, bool fast, char **labelfile)
 	FILE	   *fp;
 	StringInfoData labelfbuf;
 
-	if (!superuser() && !is_authenticated_user_replication_role())
+	if (!superuser() && !has_rolreplication(GetUserId()))
 		ereport(ERROR,
 				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
 		   errmsg("must be superuser or replication role to run a backup")));
@@ -9261,7 +9261,7 @@ do_pg_stop_backup(char *labelfile, bool waitforarchive)
 	bool		reported_waiting = false;
 	char	   *remaining;
 
-	if (!superuser() && !is_authenticated_user_replication_role())
+	if (!superuser() && !has_rolreplication(GetUserId()))
 		ereport(ERROR,
 				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
 		 (errmsg("must be superuser or replication role to run a backup"))));
diff --git a/src/backend/utils/init/miscinit.c b/src/backend/utils/init/miscinit.c
index f6cd0c06759..25cbf60e657 100644
--- a/src/backend/utils/init/miscinit.c
+++ b/src/backend/utils/init/miscinit.c
@@ -389,15 +389,15 @@ SetUserIdAndContext(Oid userid, bool sec_def_context)
 
 
 /*
- * Check if the authenticated user is a replication role
+ * Check whether specified role has explicit REPLICATION privilege
  */
 bool
-is_authenticated_user_replication_role(void)
+has_rolreplication(Oid roleid)
 {
 	bool		result = false;
 	HeapTuple	utup;
 
-	utup = SearchSysCache1(AUTHOID, ObjectIdGetDatum(AuthenticatedUserId));
+	utup = SearchSysCache1(AUTHOID, ObjectIdGetDatum(roleid));
 	if (HeapTupleIsValid(utup))
 	{
 		result = ((Form_pg_authid) GETSTRUCT(utup))->rolreplication;
diff --git a/src/backend/utils/init/postinit.c b/src/backend/utils/init/postinit.c
index dfe338c2bfe..efb48d92ec2 100644
--- a/src/backend/utils/init/postinit.c
+++ b/src/backend/utils/init/postinit.c
@@ -669,7 +669,7 @@ InitPostgres(const char *in_dbname, Oid dboid, const char *username,
 		Assert(!bootstrap);
 
 		/* must have authenticated as a replication role */
-		if (!is_authenticated_user_replication_role())
+		if (!has_rolreplication(GetUserId()))
 			ereport(FATAL,
 					(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
 					 errmsg("must be replication role to start walsender")));
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 29363ead1a0..82af9ab89fa 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -395,7 +395,7 @@ extern void ValidatePgVersion(const char *path);
 extern void process_shared_preload_libraries(void);
 extern void process_local_preload_libraries(void);
 extern void pg_bindtextdomain(const char *domain);
-extern bool is_authenticated_user_replication_role(void);
+extern bool has_rolreplication(Oid roleid);
 
 /* in access/transam/xlog.c */
 extern bool BackupInProgress(void);