Fix for bug #58499 "DEFINER-security view selecting from

INVOKER-security view access check wrong".

When privilege checks were done for tables used from an 
INVOKER-security view which in its turn was used from 
a DEFINER-security view connection's active security
context was incorrectly used instead of security context
with privileges of the second view's creator.

This meant that users which had enough rights to access
the DEFINER-security view and as result were supposed to 
be able successfully access it were unable to do so in 
cases when they didn't have privileges on underlying tables 
of the INVOKER-security view.

This problem was caused by the fact that for INVOKER-security
views TABLE_LIST::security_ctx member for underlying tables
were set to 0 even in cases when particular view was used from 
another DEFINER-security view. This meant that when checks of
privileges on these underlying tables was done in
setup_tables_and_check_access() active connection security 
context was used instead of context corresponding to the 
creator of caller view.

This fix addresses the problem by ensuring that underlying
tables of an INVOKER-security view inherit security context
from the view and thus correct security context is used for
privilege checks on underlying tables in cases when such view 
is used from another view with DEFINER-security.

mysql-test/r/view_grant.result:
  Added coverage for various combinations of DEFINER and
  INVOKER-security views, including test for bug #58499
  "DEFINER-security view selecting from INVOKER-security
  view access check wrong".
mysql-test/t/view_grant.test:
  Added coverage for various combinations of DEFINER and
  INVOKER-security views, including test for bug #58499
  "DEFINER-security view selecting from INVOKER-security
  view access check wrong".
sql/sql_view.cc:
  When opening a non-suid view ensure that its underlying 
  tables will get the same security context as use for
  checking privileges on the view, i.e. security context
  of view invoker. This context can be different from the
  security context which is currently active for connection 
  in cases when this non-suid view is used from a view with
  suid security. Inheriting security context in such situation
  allows correctly apply privileges of creator of suid view
  in checks for tables of non-suid view (since in this 
  situation creator/definer of suid view serves as invoker
  for non-suid view).

1 files changed, 126 insertions, 0 deletions

diff --git a/mysql-test/r/view_grant.result b/mysql-test/r/view_grant.result
index 52c8bc8a3d5..0348a8428a5 100644
--- a/mysql-test/r/view_grant.result
+++ b/mysql-test/r/view_grant.result
@@ -1248,3 +1248,129 @@ Note	1449	The user specified as a definer ('unknown'@'unknown') does not exist
 LOCK TABLES v1 READ;
 ERROR HY000: The user specified as a definer ('unknown'@'unknown') does not exist
 DROP VIEW v1;
+#
+# Bug #58499 "DEFINER-security view selecting from INVOKER-security view
+#             access check wrong".
+#
+# Check that we correctly handle privileges for various combinations
+# of INVOKER and DEFINER-security views using each other.
+DROP DATABASE IF EXISTS mysqltest1;
+CREATE DATABASE mysqltest1;
+USE mysqltest1;
+CREATE TABLE t1 (i INT);
+CREATE TABLE t2 (j INT);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t2 VALUES (2);
+#
+# 1) DEFINER-security view uses INVOKER-security view (covers
+#    scenario originally described in the bug report).
+CREATE SQL SECURITY INVOKER VIEW v1_uses_t1 AS SELECT * FROM t1;
+CREATE SQL SECURITY INVOKER VIEW v1_uses_t2 AS SELECT * FROM t2;
+CREATE USER 'mysqluser1'@'%';
+GRANT CREATE VIEW ON mysqltest1.* TO 'mysqluser1'@'%';
+GRANT SELECT ON t1 TO 'mysqluser1'@'%';
+# To be able create 'v2_uses_t2' we also need select on t2. 
+GRANT SELECT ON t2 TO 'mysqluser1'@'%';
+GRANT SELECT ON v1_uses_t1 TO 'mysqluser1'@'%';
+GRANT SELECT ON v1_uses_t2 TO 'mysqluser1'@'%';
+#
+# Connection 'mysqluser1'.
+CREATE SQL SECURITY DEFINER VIEW v2_uses_t1 AS SELECT * FROM v1_uses_t1;
+CREATE SQL SECURITY DEFINER VIEW v2_uses_t2 AS SELECT * FROM v1_uses_t2;
+#
+# Connection 'default'.
+CREATE USER 'mysqluser2'@'%';
+GRANT SELECT ON v2_uses_t1 TO 'mysqluser2'@'%';
+GRANT SELECT ON v2_uses_t2 TO 'mysqluser2'@'%';
+GRANT SELECT ON t2 TO 'mysqluser2'@'%';
+GRANT CREATE VIEW ON mysqltest1.* TO 'mysqluser2'@'%';
+# Make 'mysqluser1' unable to access t2.
+REVOKE SELECT ON t2 FROM 'mysqluser1'@'%';
+#
+# Connection 'mysqluser2'.
+# The below statement should succeed thanks to suid nature of v2_uses_t1.
+SELECT * FROM v2_uses_t1;
+i
+1
+# The below statement should fail due to suid nature of v2_uses_t2.
+SELECT * FROM v2_uses_t2;
+ERROR HY000: View 'mysqltest1.v2_uses_t2' references invalid table(s) or column(s) or function(s) or definer/invoker of view lack rights to use them
+#
+# 2) INVOKER-security view uses INVOKER-security view.
+#
+# Connection 'default'.
+DROP VIEW v2_uses_t1, v2_uses_t2;
+CREATE SQL SECURITY INVOKER VIEW v2_uses_t1 AS SELECT * FROM v1_uses_t1;
+CREATE SQL SECURITY INVOKER VIEW v2_uses_t2 AS SELECT * FROM v1_uses_t2;
+GRANT SELECT ON v2_uses_t1 TO 'mysqluser1'@'%';
+GRANT SELECT ON v2_uses_t2 TO 'mysqluser1'@'%';
+GRANT SELECT ON v1_uses_t1 TO 'mysqluser2'@'%';
+GRANT SELECT ON v1_uses_t2 TO 'mysqluser2'@'%';
+#
+# Connection 'mysqluser1'.
+# For both versions of 'v2' 'mysqluser1' privileges should be used.
+SELECT * FROM v2_uses_t1;
+i
+1
+SELECT * FROM v2_uses_t2;
+ERROR HY000: View 'mysqltest1.v2_uses_t2' references invalid table(s) or column(s) or function(s) or definer/invoker of view lack rights to use them
+#
+# Connection 'mysqluser2'.
+# And now for both versions of 'v2' 'mysqluser2' privileges should
+# be used.
+SELECT * FROM v2_uses_t1;
+ERROR HY000: View 'mysqltest1.v2_uses_t1' references invalid table(s) or column(s) or function(s) or definer/invoker of view lack rights to use them
+SELECT * FROM v2_uses_t2;
+j
+2
+#
+# 3) INVOKER-security view uses DEFINER-security view.
+#
+# Connection 'default'.
+DROP VIEW v1_uses_t1, v1_uses_t2;
+# To be able create 'v1_uses_t2' we also need select on t2. 
+GRANT SELECT ON t2 TO 'mysqluser1'@'%';
+#
+# Connection 'mysqluser1'.
+CREATE SQL SECURITY DEFINER VIEW v1_uses_t1 AS SELECT * FROM t1;
+CREATE SQL SECURITY DEFINER VIEW v1_uses_t2 AS SELECT * FROM t2;
+#
+# Connection 'default'.
+# Make 'mysqluser1' unable to access t2.
+REVOKE SELECT ON t2 FROM 'mysqluser1'@'%';
+#
+# Connection 'mysqluser2'.
+# Due to suid nature of v1_uses_t1 and v1_uses_t2 the first
+# select should succeed and the second select should fail.
+SELECT * FROM v2_uses_t1;
+i
+1
+SELECT * FROM v2_uses_t2;
+ERROR HY000: View 'mysqltest1.v2_uses_t2' references invalid table(s) or column(s) or function(s) or definer/invoker of view lack rights to use them
+#
+# 4) DEFINER-security view uses DEFINER-security view.
+#
+# Connection 'default'.
+DROP VIEW v2_uses_t1, v2_uses_t2;
+# To be able create 'v2_uses_t2' we also need select on t2. 
+GRANT SELECT ON t2 TO 'mysqluser1'@'%';
+#
+# Connection 'mysqluser2'.
+CREATE SQL SECURITY DEFINER VIEW v2_uses_t1 AS SELECT * FROM v1_uses_t1;
+CREATE SQL SECURITY DEFINER VIEW v2_uses_t2 AS SELECT * FROM v1_uses_t2;
+#
+# Connection 'default'.
+# Make 'mysqluser1' unable to access t2.
+REVOKE SELECT ON t2 FROM 'mysqluser1'@'%';
+#
+# Connection 'mysqluser2'.
+# Again privileges of creator of innermost views should apply.
+SELECT * FROM v2_uses_t1;
+i
+1
+SELECT * FROM v2_uses_t2;
+ERROR HY000: View 'mysqltest1.v2_uses_t2' references invalid table(s) or column(s) or function(s) or definer/invoker of view lack rights to use them
+USE test;
+DROP DATABASE mysqltest1;
+DROP USER 'mysqluser1'@'%';
+DROP USER 'mysqluser2'@'%';