Code review for row security.

Buildfarm member tick identified an issue where the policies in the
relcache for a relation were were being replaced underneath a running
query, leading to segfaults while processing the policies to be added
to a query.  Similar to how TupleDesc RuleLocks are handled, add in a
equalRSDesc() function to check if the policies have actually changed
and, if not, swap back the rsdesc field (using the original instead of
the temporairly built one; the whole structure is swapped and then
specific fields swapped back).  This now passes a CLOBBER_CACHE_ALWAYS
for me and should resolve the buildfarm error.

In addition to addressing this, add a new chapter in Data Definition
under Privileges which explains row security and provides examples of
its usage, change \d to always list policies (even if row security is
disabled- but note that it is disabled, or enabled with no policies),
rework check_role_for_policy (it really didn't need the entire policy,
but it did need to be using has_privs_of_role()), and change the field
in pg_class to relrowsecurity from relhasrowsecurity, based on
Heikki's suggestion.  Also from Heikki, only issue SET ROW_SECURITY in
pg_restore when talking to a 9.5+ server, list Bypass RLS in \du, and
document --enable-row-security options for pg_dump and pg_restore.

Lastly, fix a number of minor whitespace and typo issues from Heikki,
Dimitri, add a missing #include, per Peter E, fix a few minor
variable-assigned-but-not-used and resource leak issues from Coverity
and add tab completion for role attribute bypassrls as well.

1 files changed, 20 insertions, 18 deletions

diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index a4594b6783c..886188c036f 100644
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@@ -1214,11 +1214,12 @@ psql_completion(const char *text, int start, int end)
 			  pg_strcasecmp(prev2_wd, "ROLE") == 0))
 	{
 		static const char *const list_ALTERUSER[] =
-		{"CONNECTION LIMIT", "CREATEDB", "CREATEROLE", "CREATEUSER",
-			"ENCRYPTED", "INHERIT", "LOGIN", "NOCREATEDB", "NOCREATEROLE",
-			"NOCREATEUSER", "NOINHERIT", "NOLOGIN", "NOREPLICATION",
-			"NOSUPERUSER", "RENAME TO", "REPLICATION", "RESET", "SET",
-		"SUPERUSER", "UNENCRYPTED", "VALID UNTIL", "WITH", NULL};
+		{"BYPASSRLS", "CONNECTION LIMIT", "CREATEDB", "CREATEROLE",
+			"CREATEUSER", "ENCRYPTED", "INHERIT", "LOGIN", "NOBYPASSRLS",
+			"NOCREATEDB", "NOCREATEROLE", "NOCREATEUSER", "NOINHERIT",
+			"NOLOGIN", "NOREPLICATION", "NOSUPERUSER", "RENAME TO",
+			"REPLICATION", "RESET", "SET", "SUPERUSER", "UNENCRYPTED",
+		"VALID UNTIL", "WITH", NULL};
 
 		COMPLETE_WITH_LIST(list_ALTERUSER);
 	}
@@ -1231,11 +1232,12 @@ psql_completion(const char *text, int start, int end)
 	{
 		/* Similar to the above, but don't complete "WITH" again. */
 		static const char *const list_ALTERUSER_WITH[] =
-		{"CONNECTION LIMIT", "CREATEDB", "CREATEROLE", "CREATEUSER",
-			"ENCRYPTED", "INHERIT", "LOGIN", "NOCREATEDB", "NOCREATEROLE",
-			"NOCREATEUSER", "NOINHERIT", "NOLOGIN", "NOREPLICATION",
-			"NOSUPERUSER", "RENAME TO", "REPLICATION", "RESET", "SET",
-		"SUPERUSER", "UNENCRYPTED", "VALID UNTIL", NULL};
+		{"BYPASSRLS", "CONNECTION LIMIT", "CREATEDB", "CREATEROLE",
+			"CREATEUSER", "ENCRYPTED", "INHERIT", "LOGIN", "NOBYPASSRLS",
+			"NOCREATEDB", "NOCREATEROLE", "NOCREATEUSER", "NOINHERIT",
+			"NOLOGIN", "NOREPLICATION", "NOSUPERUSER", "RENAME TO",
+			"REPLICATION", "RESET", "SET", "SUPERUSER", "UNENCRYPTED",
+		"VALID UNTIL", NULL};
 
 		COMPLETE_WITH_LIST(list_ALTERUSER_WITH);
 	}
@@ -2565,10 +2567,10 @@ psql_completion(const char *text, int start, int end)
 			  pg_strcasecmp(prev2_wd, "GROUP") == 0 || pg_strcasecmp(prev2_wd, "USER") == 0))
 	{
 		static const char *const list_CREATEROLE[] =
-		{"ADMIN", "CONNECTION LIMIT", "CREATEDB", "CREATEROLE", "CREATEUSER",
-			"ENCRYPTED", "IN", "INHERIT", "LOGIN", "NOCREATEDB",
-			"NOCREATEROLE", "NOCREATEUSER", "NOINHERIT", "NOLOGIN",
-			"NOREPLICATION", "NOSUPERUSER", "REPLICATION", "ROLE",
+		{"ADMIN", "BYPASSRLS", "CONNECTION LIMIT", "CREATEDB", "CREATEROLE",
+			"CREATEUSER", "ENCRYPTED", "IN", "INHERIT", "LOGIN", "NOBYPASSRLS",
+			"NOCREATEDB", "NOCREATEROLE", "NOCREATEUSER", "NOINHERIT",
+			"NOLOGIN", "NOREPLICATION", "NOSUPERUSER", "REPLICATION", "ROLE",
 		"SUPERUSER", "SYSID", "UNENCRYPTED", "VALID UNTIL", "WITH", NULL};
 
 		COMPLETE_WITH_LIST(list_CREATEROLE);
@@ -2583,10 +2585,10 @@ psql_completion(const char *text, int start, int end)
 	{
 		/* Similar to the above, but don't complete "WITH" again. */
 		static const char *const list_CREATEROLE_WITH[] =
-		{"ADMIN", "CONNECTION LIMIT", "CREATEDB", "CREATEROLE", "CREATEUSER",
-			"ENCRYPTED", "IN", "INHERIT", "LOGIN", "NOCREATEDB",
-			"NOCREATEROLE", "NOCREATEUSER", "NOINHERIT", "NOLOGIN",
-			"NOREPLICATION", "NOSUPERUSER", "REPLICATION", "ROLE",
+		{"ADMIN", "BYPASSRLS", "CONNECTION LIMIT", "CREATEDB", "CREATEROLE",
+			"CREATEUSER", "ENCRYPTED", "IN", "INHERIT", "LOGIN", "NOBYPASSRLS",
+			"NOCREATEDB", "NOCREATEROLE", "NOCREATEUSER", "NOINHERIT",
+			"NOLOGIN", "NOREPLICATION", "NOSUPERUSER", "REPLICATION", "ROLE",
 		"SUPERUSER", "SYSID", "UNENCRYPTED", "VALID UNTIL", NULL};
 
 		COMPLETE_WITH_LIST(list_CREATEROLE_WITH);