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 <postg...@jeltef.nl> Reviewed-by: Robert Haas <robertmh...@gmail.com> (earlier versions) Discussion: https://www.postgresql.org/message-id/508d0505-8b7a-4864-a681-e7e5edfe3...@iki.fi Branch ------ master Details ------- https://git.postgresql.org/pg/commitdiff/a460251f0a1ac987f0225203ff9593704da0b1a9 Modified Files -------------- doc/src/sgml/protocol.sgml | 29 +++++- src/backend/storage/ipc/procsignal.c | 23 ++--- src/backend/tcop/backend_startup.c | 55 ++++++----- src/backend/tcop/postgres.c | 15 ++- src/backend/utils/init/globals.c | 5 +- src/backend/utils/init/postinit.c | 2 +- src/include/libpq/pqcomm.h | 8 +- src/include/miscadmin.h | 4 +- src/include/storage/procsignal.h | 14 ++- src/interfaces/libpq/fe-cancel.c | 102 +++++++++++++++++---- src/interfaces/libpq/fe-connect.c | 15 ++- src/interfaces/libpq/fe-protocol3.c | 45 ++++++++- src/interfaces/libpq/libpq-int.h | 7 +- .../modules/libpq_pipeline/t/001_libpq_pipeline.pl | 12 ++- 14 files changed, 252 insertions(+), 84 deletions(-)
