pgsql: Send ALPN in TLS handshake, require it in direct SSL connections

Started by Heikki Linnakangasover 2 years ago3 messagescomitters
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#1Heikki Linnakangas
heikki.linnakangas@enterprisedb.com

Send ALPN in TLS handshake, require it in direct SSL connections

libpq now always tries to send ALPN. With the traditional negotiated
SSL connections, the server accepts the ALPN, and refuses the
connection if it's not what we expect, but connecting without ALPN is
still OK. With the new direct SSL connections, ALPN is mandatory.

NOTE: This uses "TBD-pgsql" as the protocol ID. We must register a
proper one with IANA before the release!

Author: Greg Stark, Heikki Linnakangas
Reviewed-by: Matthias van de Meent, Jacob Champion

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/91044ae4baeac2e501e34164a69bd5d9c4976d21

Modified Files
--------------
doc/src/sgml/libpq.sgml | 12 +++++
src/backend/libpq/be-secure-openssl.c | 77 ++++++++++++++++++++++++++++++++
src/backend/tcop/backend_startup.c | 8 ++++
src/bin/psql/command.c | 7 ++-
src/include/libpq/libpq-be.h | 1 +
src/include/libpq/pqcomm.h | 19 ++++++++
src/interfaces/libpq/fe-secure-openssl.c | 35 +++++++++++++++
7 files changed, 157 insertions(+), 2 deletions(-)

#2Andres Freund
andres@anarazel.de
In reply to: Heikki Linnakangas (#1)
Re: pgsql: Send ALPN in TLS handshake, require it in direct SSL connections

Hi,

On 2024-04-08 01:25:40 +0000, Heikki Linnakangas wrote:

Send ALPN in TLS handshake, require it in direct SSL connections

libpq now always tries to send ALPN. With the traditional negotiated
SSL connections, the server accepts the ALPN, and refuses the
connection if it's not what we expect, but connecting without ALPN is
still OK. With the new direct SSL connections, ALPN is mandatory.

NOTE: This uses "TBD-pgsql" as the protocol ID. We must register a
proper one with IANA before the release!

Author: Greg Stark, Heikki Linnakangas
Reviewed-by: Matthias van de Meent, Jacob Champion

My compiler complains:

[396/992 42 39%] Compiling C object src/backend/postgres_lib.a.p/libpq_be-secure-openssl.c.o
../../../../../home/andres/src/postgresql/src/backend/libpq/be-secure-openssl.c: In function 'alpn_cb':
../../../../../home/andres/src/postgresql/src/backend/libpq/be-secure-openssl.c:1327:69: warning: ordered comparison of pointer with integer zero [-Wextra]
1327 | if (*out == NULL || *outlen > sizeof(alpn_protos) || outlen <= 0)
| ^~
[991/992 1 99%] Linking target src/bin/pg_dump/pg_dump

And I think it may show why the warning is a good idea - I assume
"*outlen <= 0" was intended?

Greetings,

Andres Freund

#3Heikki Linnakangas
heikki.linnakangas@enterprisedb.com
In reply to: Andres Freund (#2)
Re: pgsql: Send ALPN in TLS handshake, require it in direct SSL connections

On 08/04/2024 04:50, Andres Freund wrote:

On 2024-04-08 01:25:40 +0000, Heikki Linnakangas wrote:

Send ALPN in TLS handshake, require it in direct SSL connections

libpq now always tries to send ALPN. With the traditional negotiated
SSL connections, the server accepts the ALPN, and refuses the
connection if it's not what we expect, but connecting without ALPN is
still OK. With the new direct SSL connections, ALPN is mandatory.

NOTE: This uses "TBD-pgsql" as the protocol ID. We must register a
proper one with IANA before the release!

Author: Greg Stark, Heikki Linnakangas
Reviewed-by: Matthias van de Meent, Jacob Champion

My compiler complains:

[396/992 42 39%] Compiling C object src/backend/postgres_lib.a.p/libpq_be-secure-openssl.c.o
../../../../../home/andres/src/postgresql/src/backend/libpq/be-secure-openssl.c: In function 'alpn_cb':
../../../../../home/andres/src/postgresql/src/backend/libpq/be-secure-openssl.c:1327:69: warning: ordered comparison of pointer with integer zero [-Wextra]
1327 | if (*out == NULL || *outlen > sizeof(alpn_protos) || outlen <= 0)
| ^~
[991/992 1 99%] Linking target src/bin/pg_dump/pg_dump

And I think it may show why the warning is a good idea - I assume
"*outlen <= 0" was intended?

Yes. Fixed, thanks!

--
Heikki Linnakangas
Neon (https://neon.tech)