Package Instance

TemporaryFolder on unix-like systems does not limit access to created files
**Vulnerability**

`PreparedStatement.setText(int, InputStream)`
and

`PreparedStatemet.setBytea(int, InputStream)`

will create a temporary file if the InputStream is larger than 51k

 
Example of vulnerable code:

```java
String s = "some very large string greater than 51200 bytes";

PreparedStatement.setInputStream(1, new ByteArrayInputStream(s.getBytes()) );
```
This will create a temporary file which is readable by other users on Unix like systems, but not MacOS.

Impact
On Unix like systems, the system's temporary directory is shared between all users on that system. Because of this, when files and directories are written into this directory they are, by default, readable by other users on that same system.

This vulnerability does not allow other users to overwrite the contents of these directories or files. This is purely an information disclosure vulnerability.

When analyzing the impact of this vulnerability, here are the important questions to ask:

Is the driver running in an environment where the OS has other untrusted users.
If yes, and you answered 'yes' to question 1, this vulnerability impacts you.
If no, this vulnerability does not impact you.
Patches
Because certain JDK file system APIs were only added in JDK 1.7, this this fix is dependent upon the version of the JDK you are using.

Java 1.8 and higher users: this vulnerability is fixed in 42.2.27, 42.3.8, 42.4.3, 42.5.1
Java 1.7 users: this vulnerability is fixed in 42.2.27.jre7
Java 1.6 and lower users: no patch is available; you must use the workaround below.
Workarounds
If you are unable to patch, or are stuck running on Java 1.6, specifying the java.io.tmpdir system environment variable to a directory that is exclusively owned by the executing user will fix this vulnerability.

References
[CWE-200: Exposure of Sensitive Information to an Unauthorized Actor](https://cwe.mitre.org/data/definitions/200.html)
Fix commit https://github.com/pgjdbc/pgjdbc/commit/9008dc9aade6dbfe4efafcd6872ebc55f4699cf5
Similar Vulnerabilities
Google Guava - https://github.com/google/guava/issues/4011
Apache Ant - https://nvd.nist.gov/vuln/detail/CVE-2020-1945
JetBrains Kotlin Compiler - https://nvd.nist.gov/vuln/detail/CVE-2020-15824

PostgreSQL JDBC Driver SQL Injection in ResultSet.refreshRow() with malicious column names
### Impact
_What kind of vulnerability is it? Who is impacted?_

The PGJDBC implementation of the `java.sql.ResultRow.refreshRow()` method is not performing escaping of column names so a malicious column name that contains a statement terminator, e.g. `;`, could lead to SQL injection. This could lead to executing additional SQL commands as the application's JDBC user.

User applications that do not invoke the `ResultSet.refreshRow()` method are not impacted.

User application that do invoke that method are impacted if the underlying database that they are querying via their JDBC application may be under the control of an attacker. The attack requires the attacker to trick the user into executing SQL against a table name who's column names would contain the malicious SQL and subsequently invoke the `refreshRow()` method on the ResultSet.

For example:

```sql
CREATE TABLE refresh_row_example (
  id     int PRIMARY KEY,
  "1 FROM refresh_row_example; SELECT pg_sleep(10); SELECT * " int
);
```

This example has a table with two columns. The name of the second column is crafted to contain a statement terminator followed by additional SQL. Invoking the `ResultSet.refreshRow()` on a ResultSet that queried this table, e.g. `SELECT * FROM refresh_row`, would cause the additional SQL commands such as the `SELECT pg_sleep(10)` invocation to be executed.

As the multi statement command would contain multiple results, it would not be possible for the attacker to get data directly out of this approach as the `ResultSet.refreshRow()` method would throw an exception. However, the attacker could execute any arbitrary SQL including inserting the data into another table that could then be read or any other DML / DDL statement.

Note that the application's JDBC user and the schema owner need not be the same. A JDBC application that executes as a privileged user querying database schemas owned by potentially malicious less-privileged users would be vulnerable. In that situation it may be possible for the malicious user to craft a schema that causes the application to execute commands as the privileged user.

### Patches
_Has the problem been patched? What versions should users upgrade to?_

Yes, versions 42.2.26, 42.3.7, and 42.4.1 have been released with a fix.

### Workarounds
_Is there a way for users to fix or remediate the vulnerability without upgrading?_

Check that you are not using the `ResultSet.refreshRow()` method.

If you are, ensure that the code that executes that method does not connect to a database that is controlled by an unauthenticated or malicious user. If your application only connects to its own database with a fixed schema with no DDL permissions, then you will not be affected by this vulnerability as it requires a maliciously crafted schema.