diff options
| author | Heikki Linnakangas | 2025-04-02 13:41:48 +0000 |
|---|---|---|
| committer | Heikki Linnakangas | 2025-04-02 13:41:48 +0000 |
| commit | a460251f0a1ac987f0225203ff9593704da0b1a9 (patch) | |
| tree | 009893fb5dc0e934b15abf6eabfe20fda63b3d4d /src/include/libpq | |
| parent | 285613c60a7aff5daaf281c67002483b0d26e715 (diff) | |
Make cancel request keys longer
Currently, the cancel request key is a 32-bit token, which isn't very
much entropy. If you want to cancel another session's query, you can
brute-force it. In most environments, an unauthorized cancellation of
a query isn't very serious, but it nevertheless would be nice to have
more protection from it. Hence make the key longer, to make it harder
to guess.
The longer cancellation keys are generated when using the new protocol
version 3.2. For connections using version 3.0, short 4-bytes keys are
still used.
The new longer key length is not hardcoded in the protocol anymore,
the client is expected to deal with variable length keys, up to 256
bytes. This flexibility allows e.g. a connection pooler to add more
information to the cancel key, which might be useful for finding the
connection.
Reviewed-by: Jelte Fennema-Nio <postgres@jeltef.nl>
Reviewed-by: Robert Haas <robertmhaas@gmail.com> (earlier versions)
Discussion: https://www.postgresql.org/message-id/508d0505-8b7a-4864-a681-e7e5edfe32aa@iki.fi
Diffstat (limited to 'src/include/libpq')
| -rw-r--r-- | src/include/libpq/pqcomm.h | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/src/include/libpq/pqcomm.h b/src/include/libpq/pqcomm.h index 0aceb7147c7..d11069cf8dc 100644 --- a/src/include/libpq/pqcomm.h +++ b/src/include/libpq/pqcomm.h @@ -128,7 +128,12 @@ typedef uint32 AuthRequest; * * The cancel request code must not match any protocol version number * we're ever likely to use. This random choice should do. + * + * Before PostgreSQL v18 and the protocol version bump from 3.0 to 3.2, the + * cancel key was always 4 bytes. With protocol version 3.2, it's variable + * length. */ + #define CANCEL_REQUEST_CODE PG_PROTOCOL(1234,5678) typedef struct CancelRequestPacket @@ -136,7 +141,8 @@ typedef struct CancelRequestPacket /* Note that each field is stored in network byte order! */ MsgType cancelRequestCode; /* code to identify a cancel request */ uint32 backendPID; /* PID of client's backend */ - uint32 cancelAuthCode; /* secret key to authorize cancel */ + char cancelAuthCode[FLEXIBLE_ARRAY_MEMBER]; /* secret key to + * authorize cancel */ } CancelRequestPacket; /* Application-Layer Protocol Negotiation is required for direct connections |