f76f6dbccb
In CQL, table names are limited to so-called word characters (letters, numbers and underscores), but column names don't have such a limitation. When we create a secondary index, its default name is constructed from the column name - so can contain problematic characters. It can include even the "/" character. The problem is that the index name is then used, like a table name, to create a directory with that name. The test included in this patch demonstrates that before this patch, this can be misused to create subdirectories anywhere in the filesystem, or to crash Scylla when it fails to create a directory (which it considers an unrecoverable I/O error). In this patch we do what Cassandra does - remove all non-word characters from the indexed column name before constructing the default index name. In the included test - which can run on both Scylla and Cassandra - we verify that the constructed index name is the same as in Cassandra, which is useful to know (e.g., because knowing the index name is needed to DROP the index). Also, this patch adds a second line of defense against the security problem described above: It is now an error to create a schema with a slash or null (the two characters not allowed in Unix filenames) in the keyspace or table names. So if the first line of defense (CQL checking the validity of its commands) fails, we'll have that second line of defense. I verified that if I revert the default-index-name fix, the second line of defense kicks in, and the index creation is aborted and cannot create files in the wrong place to crash Scylla. Fixes #3403 Signed-off-by: Nadav Har'El <nyh@scylladb.com> Message-Id: <20220320162543.3091121-1-nyh@scylladb.com>
Scylla Developer Documentation
This documentation targets developers who are interested in contributing to Scylla codebase.
Contents
- Alternator - The open source DynamoDB-compatible API reference.
- Design notes - Explanations describing how new features work for other contributors and exploratory research.
- Guides - Instructions on how to build, run, test and debug the Scylla codebase.
- Contribute - Guidelines on how to contribute and maintain the project.