Memory-safety vulnerability in github.com/jackc/pgx/v5.

Memory-safety vulnerability in github.com/jackc/pgx/v5.

The DataRow.Decode function fails to properly validate field lengths. A malicious or compromised PostgreSQL server can send a DataRow message with a negative field length, causing a slice bounds out of range panic.

pgx is a PostgreSQL driver and toolkit for Go. Prior to version 5.9.2, SQL injection can occur when the non-default simple protocol is used, a dollar quoted string literal is used in the SQL query, that string literal contains text that would be would be interpreted as a placeholder outside of a string literal, and the value of that placeholder is controllable by the attacker. This issue has been patched in version 5.9.2.

Impact

SQL injection can occur if an attacker can cause a single query or bind message to exceed 4 GB in size. An integer overflow in the calculated message size can cause the one large message to be sent as multiple messages under the attacker's control.

Patches

The problem is resolved in v4.18.2 and v5.5.4.

Workarounds

Reject user input large enough to cause a single query or bind message to exceed 4 GB in size.

Impact

SQL injection can occur when all of the following conditions are met:

1. The non-default simple protocol is used. 2. A placeholder for a numeric value must be immediately preceded by a minus. 3. There must be a second placeholder for a string value after the first placeholder; both must be on the same line. 4. Both parameter values must be user-controlled.

e.g.

Simple mode must be enabled:

go // connection string includes "prefersimpleprotocol=true" // or // directly enabled in code config.ConnConfig.PreferSimpleProtocol = true

Parameterized query:

sql SELECT FROM example WHERE result=-$1 OR name=$2;

Parameter values:

$1 => -42 $2 => "foo\n 1 AND 1=0 UNION SELECT FROM secrets; --"

Resulting query after preparation:

sql SELECT FROM example WHERE result=--42 OR name= 'foo 1 AND 1=0 UNION SELECT FROM secrets; --';

Patches

The problem is resolved in v4.18.2.

Workarounds

Do not use the simple protocol or do not place a minus directly before a placeholder.