[tarantool-patches] [PATCH v1 1/1] sql: check that received iterator is not NULL

[imeevma@tarantool.org]

If the user does not have permission to read from the “_collation”
space, the “PRAGMA collation_list” command causes a segmentation
fault. Added new check.

Closes #3857
---
https://github.com/tarantool/tarantool/issues/3857
https://github.com/tarantool/tarantool/tree/imeevma/gh-3857-add-check-for-received-iterator

 src/box/sql/pragma.c        |  5 +++++
 test/sql/collation.result   | 18 ++++++++++++++++++
 test/sql/collation.test.lua |  8 ++++++++
 3 files changed, 31 insertions(+)

diff --git a/src/box/sql/pragma.c b/src/box/sql/pragma.c
index 5c35017..2b0d812 100644
--- a/src/box/sql/pragma.c
+++ b/src/box/sql/pragma.c
@@ -521,6 +521,11 @@ sqlite3Pragma(Parse * pParse, Token * pId,	/* First part of [schema.]id field */
 		box_tuple_t *tuple;
 		box_iterator_t* iter;
 		iter = box_index_iterator(space->def->id, 0,ITER_ALL, key_buf, key_end);
+		if (iter == NULL) {
+			pParse->rc = SQL_TARANTOOL_ERROR;
+			pParse->nErr++;
+			goto pragma_out;
+		}
 		int rc = box_iterator_next(iter, &tuple);
 		(void) rc;
 		assert(rc == 0);
diff --git a/test/sql/collation.result b/test/sql/collation.result
index f98e9cb..148a1a1 100644
--- a/test/sql/collation.result
+++ b/test/sql/collation.result
@@ -243,3 +243,21 @@ box.sql.execute("DROP TABLE t;")
 box.schema.user.revoke('guest', 'read,write,execute', 'universe')
 ---
 ...
+-- gh-3857 "PRAGMA collation_list" invokes segmentation fault.
+box.schema.user.create('tmp')
+---
+...
+box.session.su('tmp')
+---
+...
+-- Error: read access to space is denied.
+box.sql.execute("pragma collation_list")
+---
+- error: Read access to space '_collation' is denied for user 'tmp'
+...
+box.session.su('admin')
+---
+...
+box.schema.user.drop('tmp')
+---
+...
diff --git a/test/sql/collation.test.lua b/test/sql/collation.test.lua
index c4c31fc..ade3a69 100644
--- a/test/sql/collation.test.lua
+++ b/test/sql/collation.test.lua
@@ -94,3 +94,11 @@ box.sql.execute("SELECT b COLLATE \"unicode\" FROM t UNION SELECT a FROM t;")
 
 box.sql.execute("DROP TABLE t;")
 box.schema.user.revoke('guest', 'read,write,execute', 'universe')
+
+-- gh-3857 "PRAGMA collation_list" invokes segmentation fault.
+box.schema.user.create('tmp')
+box.session.su('tmp')
+-- Error: read access to space is denied.
+box.sql.execute("pragma collation_list")
+box.session.su('admin')
+box.schema.user.drop('tmp')
-- 
2.7.4