database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-10-16 17:07:43 +03:00
Code Activity

libpq: Be strict about cancel key lengths

Browse Source 
The protocol documentation states that the maximum length of a cancel
key is 256 bytes. This starts checking for that limit in libpq.
Otherwise third party backend implementations will probably start
using more bytes anyway. We also start requiring that a protocol 3.0
connection does not send a longer cancel key, to make sure that
servers don't start breaking old 3.0-only clients by accident. Finally
this also restricts the minimum key length to 4 bytes (both in the
protocol spec and in the libpq implementation).

Author: Jelte Fennema-Nio <postgres@jeltef.nl>
Reviewed-by: Jacob Champion <jchampion@postgresql.org>
Discussion: https://www.postgresql.org/message-id/df892f9f-5923-4046-9d6f-8c48d8980b50@iki.fi
Backpatch-through: 18
This commit is contained in:
Heikki Linnakangas
2025-08-22 14:39:29 +03:00
parent f6f0542266
commit e411a8d25a
2 changed files with 22 additions and 1 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
doc/src/sgml/protocol.sgml
View File

@@ -4136,7 +4136,7 @@ psql "dbname=postgres replication=database" -c "IDENTIFY_SYSTEM;"
message, indicated by the length field.
</para>
<para>
The maximum key length is 256 bytes. The
The minimum and maximum key length are 4 and 256 bytes, respectively. The
<productname>PostgreSQL</productname> server only sends keys up to
32 bytes, but the larger maximum size allows for future server
versions, as well as connection poolers and other middleware, to use