efb8046827
We should have done it this way all along, but we accidentally got
away with using the wrong BIO field up until OpenSSL 3.2. There,
the library's BIO routines that we rely on use the "data" field
for their own purposes, and our conflicting use causes assorted
weird behaviors up to and including core dumps when SSL connections
are attempted. Switch to using the approved field for the purpose,
i.e. app_data.
While at it, remove our configure probes for BIO_get_data as well
as the fallback implementation. BIO_{get,set}_app_data have been
there since long before any OpenSSL version that we still support,
even in the back branches.
Also, update src/test/ssl/t/001_ssltests.pl to allow for a minor
change in an error message spelling that evidently came in with 3.2.
Tristan Partin and Bo Andreson. Back-patch to all supported branches.
Discussion: https://postgr.es/m/CAN55FZ1eDDYsYaL7mv+oSLUij2h_u6hvD4Qmv-7PK7jkji0uyQ@mail.gmail.com
|
||
|---|---|---|
| .. | ||
| Makefile | ||
| README.SSL | ||
| auth-scram.c | ||
| auth.c | ||
| be-fsstubs.c | ||
| be-gssapi-common.c | ||
| be-secure-common.c | ||
| be-secure-gssapi.c | ||
| be-secure-openssl.c | ||
| be-secure.c | ||
| crypt.c | ||
| hba.c | ||
| ifaddr.c | ||
| pg_hba.conf.sample | ||
| pg_ident.conf.sample | ||
| pqcomm.c | ||
| pqformat.c | ||
| pqmq.c | ||
| pqsignal.c | ||
README.SSL
src/backend/libpq/README.SSL
SSL
===
>From the servers perspective:
Receives StartupPacket
|
|
(Is SSL_NEGOTIATE_CODE?) ----------- Normal startup
| No
|
| Yes
|
|
(Server compiled with USE_SSL?) ------- Send 'N'
| No |
| |
| Yes Normal startup
|
|
Send 'S'
|
|
Establish SSL
|
|
Normal startup
>From the clients perspective (v6.6 client _with_ SSL):
Connect
|
|
Send packet with SSL_NEGOTIATE_CODE
|
|
Receive single char ------- 'S' -------- Establish SSL
| |
| '<else>' |
| Normal startup
|
|
Is it 'E' for error ------------------- Retry connection
| Yes without SSL
| No
|
Is it 'N' for normal ------------------- Normal startup
| Yes
|
Fail with unknown
---------------------------------------------------------------------------
Ephemeral DH
============
Since the server static private key ($DataDir/server.key) will
normally be stored unencrypted so that the database backend can
restart automatically, it is important that we select an algorithm
that continues to provide confidentiality even if the attacker has the
server's private key. Ephemeral DH (EDH) keys provide this and more
(Perfect Forward Secrecy aka PFS).
N.B., the static private key should still be protected to the largest
extent possible, to minimize the risk of impersonations.
Another benefit of EDH is that it allows the backend and clients to
use DSA keys. DSA keys can only provide digital signatures, not
encryption, and are often acceptable in jurisdictions where RSA keys
are unacceptable.
The downside to EDH is that it makes it impossible to use ssldump(1)
if there's a problem establishing an SSL session. In this case you'll
need to temporarily disable EDH (see initialize_dh()).