| Package | Affected versions | Patched versions |
|---|---|---|
| org.mariadb.jdbc:mariadb-java-client | ≥ 3.0.0, < 3.3.7≥ 3.4.0, < 3.4.5≥ 3.5.0, < 3.5.11 | 3.3.73.4.53.5.11 |
MariaDB Connector/J sized heap allocations from lengths declared by the server in OK packets before checking that those lengths fit in the packet. A rogue or MitM server can make the client allocate megabytes from a packet of a few bytes.
When CLIENT_SESSION_TRACK is negotiated (the default), an OK packet carries an
info field followed by session-state blocks, each tracked variable being sent as a
length-encoded name and value. OkPacket.parse() and parseWithInfo() allocated
new byte[len] for the info field, the variable name and the value with the
server-declared len, then copied the packet data into it. The copy failed with an
ArrayIndexOutOfBoundsException when the packet was shorter, but only after the
allocation had taken place.
A server-declared length of 8 MiB in an 18-byte packet was enough to trigger an 8 MiB allocation; the integer-range validation of length-encoded values does not help, since such lengths are valid positive integers.
The fix validates every server-declared length against the remaining packet bytes
before any allocation (ReadableByteBuf.checkLength() and a bounded
readBytes(int)), and stops reading the session state at the first inconsistent
entry.
Availability only: a malicious or compromised server, or a MitM, can drive
attacker-controlled heap allocations on every OK packet, creating GC pressure up to
OutOfMemoryError in the client application. Exploitation requires control of the
server side of the connection; no authentication bypass, confidentiality or
integrity impact.
Reported by fg0x0
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