On Thu, Sep 22, 2022 at 4:52 AM Peter Eisentraut
<peter.eisentr...@enterprisedb.com> wrote:
> On 22.09.22 01:37, Jacob Champion wrote:
> > I think this is potentially
> > dangerous, but it mirrors the current behavior of libpq and I'm not
> > sure that we should change it as part of this patch.
>
> It might be worth reviewing that behavior for other reasons, but I think
> semantics of your patch are correct.
Sounds good. v9 removes the TODO and adds a better explanation.
> > If you're okay with those [GSS] limitations, I will rip out the code. The
> > reason I'm not too worried about it is, I don't think it makes much
> > sense to be strict about your authentication requirements while at the
> > same time leaving the choice of transport encryption up to the server.
>
> The way I understand what you explained here is that it would be more
> sensible to leave that code in. I would be okay with that.
I've added a comment there explaining the gssencmode interaction. That
leaves no TODOs inside the code itself.
I removed the commit message note about not being able to prevent
unexpected client cert requests or GSS encryption, since we've decided
to handle those cases outside of require_auth.
I'm not able to test SSPI easily at the moment; if anyone is able to
try it out, that'd be really helpful. There's also the question of
SASL forwards compatibility -- if someone adds a new SASL mechanism,
the code will treat it like scram-sha-256 until it's changed, and
there will be no test to catch it. Should we leave that to the future
mechanism implementer to fix, or add a mechanism check now so the
client is safe even if they forget?
Thanks!
--Jacob
commit e13f21d596bc5670156a441dc6eec5228864b4b0
Author: Jacob Champion <jchamp...@timescale.com>
Date: Thu Sep 22 16:39:34 2022 -0700
squash! libpq: let client reject unexpected auth methods
Remove TODOs, and document why the code remains as-is.
diff --git a/src/interfaces/libpq/fe-auth.c b/src/interfaces/libpq/fe-auth.c
index 565e44fcf6..793888d30f 100644
--- a/src/interfaces/libpq/fe-auth.c
+++ b/src/interfaces/libpq/fe-auth.c
@@ -921,8 +921,14 @@ check_expected_areq(AuthRequest areq, PGconn *conn)
* else that the user has allowed an
authentication-less
* connection).
*
- * TODO: how should !auth_required interact
with an incomplete
- * SCRAM exchange?
+ * If the user has allowed both SCRAM and
unauthenticated
+ * (trust) connections, then this check will
silently accept
+ * partial SCRAM exchanges, where a misbehaving
server does not
+ * provide its verifier before sending an OK.
This is consistent
+ * with historical behavior, but it may be a
point to revisit in
+ * the future, since it could allow a server
that doesn't know
+ * the user's password to silently harvest
material for a brute
+ * force attack.
*/
if (!conn->auth_required ||
conn->client_finished_auth)
break;
@@ -940,10 +946,9 @@ check_expected_areq(AuthRequest areq, PGconn *conn)
/*
* If implicit GSS auth has already
been performed via GSS
* encryption, we don't need to have
performed an
- * AUTH_REQ_GSS exchange.
- *
- * TODO: check this assumption. What
mutual auth guarantees
- * are made in this case?
+ * AUTH_REQ_GSS exchange. This allows
require_auth=gss to be
+ * combined with gssencmode, since
there won't be an
+ * explicit authentication request in
that case.
*/
}
else
From f88abcb4b22499466758e566b956c487877118bb Mon Sep 17 00:00:00 2001
From: Jacob Champion <pchamp...@vmware.com>
Date: Mon, 28 Feb 2022 09:40:43 -0800
Subject: [PATCH v9 1/2] libpq: let client reject unexpected auth methods
The require_auth connection option allows the client to choose a list of
acceptable authentication types for use with the server. There is no
negotiation: if the server does not present one of the allowed
authentication requests, the connection fails. Additionally, all methods
in the list may be negated, e.g. '!password', in which case the server
must NOT use the listed authentication type. The special method "none"
allows/disallows the use of unauthenticated connections (but it does not
govern transport-level authentication via TLS or GSSAPI).
Internally, the patch expands the role of check_expected_areq() to
ensure that the incoming request is compatible with conn->require_auth.
It also introduces a new flag, conn->client_finished_auth, which is set
by various authentication routines when the client side of the handshake
is finished. This signals to check_expected_areq() that an OK message
from the server is expected, and allows the client to complain if the
server forgoes authentication entirely.
(Since the client can't generally prove that the server is actually
doing the work of authentication, this last part is mostly useful for
SCRAM without channel binding. It could also provide a client with a
decent signal that, at the very least, it's not connecting to a database
with trust auth, and so the connection can be tied to the client in a
later audit.)
Deficiencies:
- This is unlikely to be very forwards-compatible at the moment,
especially with SASL/SCRAM.
- SSPI support is "implemented" but untested.
- require_auth=none,scram-sha-256 currently allows the server to leave a
SCRAM exchange unfinished. This is not net-new behavior but may be
surprising.
---
doc/src/sgml/libpq.sgml | 105 ++++++++++++++
src/include/libpq/pqcomm.h | 1 +
src/interfaces/libpq/fe-auth-scram.c | 1 +
src/interfaces/libpq/fe-auth.c | 143 +++++++++++++++++++
src/interfaces/libpq/fe-connect.c | 164 ++++++++++++++++++++++
src/interfaces/libpq/fe-secure-openssl.c | 1 -
src/interfaces/libpq/libpq-int.h | 7 +
src/test/authentication/t/001_password.pl | 149 ++++++++++++++++++++
src/test/kerberos/t/001_auth.pl | 26 ++++
src/test/ldap/t/001_auth.pl | 6 +
src/test/ssl/t/002_scram.pl | 25 ++++
11 files changed, 627 insertions(+), 1 deletion(-)
diff --git a/doc/src/sgml/libpq.sgml b/doc/src/sgml/libpq.sgml
index 8a1a9e9932..1d6c02058e 100644
--- a/doc/src/sgml/libpq.sgml
+++ b/doc/src/sgml/libpq.sgml
@@ -1220,6 +1220,101 @@ postgresql://%2Fvar%2Flib%2Fpostgresql/dbname
</listitem>
</varlistentry>
+ <varlistentry id="libpq-connect-require-auth" xreflabel="require_auth">
+ <term><literal>require_auth</literal></term>
+ <listitem>
+ <para>
+ Specifies the authentication method that the client requires from the
+ server. If the server does not use the required method to authenticate
+ the client, or if the authentication handshake is not fully completed by
+ the server, the connection will fail. A comma-separated list of methods
+ may also be provided, of which the server must use exactly one in order
+ for the connection to succeed. By default, any authentication method is
+ accepted, and the server is free to skip authentication altogether.
+ </para>
+ <para>
+ Methods may be negated with the addition of a <literal>!</literal>
+ prefix, in which case the server must <emphasis>not</emphasis> attempt
+ the listed method; any other method is accepted, and the server is free
+ not to authenticate the client at all. If a comma-separated list is
+ provided, the server may not attempt <emphasis>any</emphasis> of the
+ listed negated methods. Negated and non-negated forms may not be
+ combined in the same setting.
+ </para>
+ <para>
+ As a final special case, the <literal>none</literal> method requires the
+ server not to use an authentication challenge. (It may also be negated,
+ to require some form of authentication.)
+ </para>
+ <para>
+ The following methods may be specified:
+
+ <variablelist>
+ <varlistentry>
+ <term><literal>password</literal></term>
+ <listitem>
+ <para>
+ The server must request plaintext password authentication.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><literal>md5</literal></term>
+ <listitem>
+ <para>
+ The server must request MD5 hashed password authentication.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><literal>gss</literal></term>
+ <listitem>
+ <para>
+ The server must either request a Kerberos handshake via
+ <acronym>GSSAPI</acronym> or establish a
+ <acronym>GSS</acronym>-encrypted channel (see also
+ <xref linkend="libpq-connect-gssencmode" />).
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><literal>sspi</literal></term>
+ <listitem>
+ <para>
+ The server must request Windows <acronym>SSPI</acronym>
+ authentication.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><literal>scram-sha-256</literal></term>
+ <listitem>
+ <para>
+ The server must successfully complete a SCRAM-SHA-256 authentication
+ exchange with the client.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><literal>none</literal></term>
+ <listitem>
+ <para>
+ The server must not prompt the client for an authentication
+ exchange. (This does not prohibit client certificate authentication
+ via TLS, nor GSS authentication via its encrypted transport.)
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </para>
+ </listitem>
+ </varlistentry>
+
<varlistentry id="libpq-connect-channel-binding" xreflabel="channel_binding">
<term><literal>channel_binding</literal></term>
<listitem>
@@ -7756,6 +7851,16 @@ myEventProc(PGEventId evtId, void *evtInfo, void *passThrough)
</para>
</listitem>
+ <listitem>
+ <para>
+ <indexterm>
+ <primary><envar>PGREQUIREAUTH</envar></primary>
+ </indexterm>
+ <envar>PGREQUIREAUTH</envar> behaves the same as the <xref
+ linkend="libpq-connect-require-auth"/> connection parameter.
+ </para>
+ </listitem>
+
<listitem>
<para>
<indexterm>
diff --git a/src/include/libpq/pqcomm.h b/src/include/libpq/pqcomm.h
index fcf68df39b..912451c913 100644
--- a/src/include/libpq/pqcomm.h
+++ b/src/include/libpq/pqcomm.h
@@ -123,6 +123,7 @@ extern PGDLLIMPORT bool Db_user_namespace;
#define AUTH_REQ_SASL 10 /* Begin SASL authentication */
#define AUTH_REQ_SASL_CONT 11 /* Continue SASL authentication */
#define AUTH_REQ_SASL_FIN 12 /* Final SASL message */
+#define AUTH_REQ_MAX AUTH_REQ_SASL_FIN /* maximum AUTH_REQ_* value */
typedef uint32 AuthRequest;
diff --git a/src/interfaces/libpq/fe-auth-scram.c b/src/interfaces/libpq/fe-auth-scram.c
index 35cfd9987d..ad57df88b6 100644
--- a/src/interfaces/libpq/fe-auth-scram.c
+++ b/src/interfaces/libpq/fe-auth-scram.c
@@ -280,6 +280,7 @@ scram_exchange(void *opaq, char *input, int inputlen,
}
*done = true;
state->state = FE_SCRAM_FINISHED;
+ state->conn->client_finished_auth = true;
break;
default:
diff --git a/src/interfaces/libpq/fe-auth.c b/src/interfaces/libpq/fe-auth.c
index 49a1c626f6..c95deffd2b 100644
--- a/src/interfaces/libpq/fe-auth.c
+++ b/src/interfaces/libpq/fe-auth.c
@@ -137,7 +137,10 @@ pg_GSS_continue(PGconn *conn, int payloadlen)
}
if (maj_stat == GSS_S_COMPLETE)
+ {
+ conn->client_finished_auth = true;
gss_release_name(&lmin_s, &conn->gtarg_nam);
+ }
return STATUS_OK;
}
@@ -326,6 +329,9 @@ pg_SSPI_continue(PGconn *conn, int payloadlen)
FreeContextBuffer(outbuf.pBuffers[0].pvBuffer);
}
+ if (r == SEC_E_OK)
+ conn->client_finished_auth = true;
+
/* Cleanup is handled by the code in freePGconn() */
return STATUS_OK;
}
@@ -830,6 +836,44 @@ pg_password_sendauth(PGconn *conn, const char *password, AuthRequest areq)
return ret;
}
+/*
+ * Translate an AuthRequest into a human-readable description.
+ */
+static const char *
+auth_description(AuthRequest areq)
+{
+ switch (areq)
+ {
+ case AUTH_REQ_PASSWORD:
+ return libpq_gettext("a cleartext password");
+ case AUTH_REQ_MD5:
+ return libpq_gettext("a hashed password");
+ case AUTH_REQ_GSS:
+ case AUTH_REQ_GSS_CONT:
+ return libpq_gettext("GSSAPI authentication");
+ case AUTH_REQ_SSPI:
+ return libpq_gettext("SSPI authentication");
+ case AUTH_REQ_SCM_CREDS:
+ return libpq_gettext("UNIX socket credentials");
+ case AUTH_REQ_SASL:
+ case AUTH_REQ_SASL_CONT:
+ case AUTH_REQ_SASL_FIN:
+ return libpq_gettext("SASL authentication");
+ }
+
+ return libpq_gettext("an unknown authentication type");
+}
+
+/*
+ * Convenience macro for checking the allowed_auth_methods bitmask. Caller must
+ * ensure that type is not greater than 31 (high bit of the bitmask).
+ */
+#define auth_allowed(conn, type) \
+ (((conn)->allowed_auth_methods & (1 << (type))) != 0)
+
+StaticAssertDecl(AUTH_REQ_MAX < CHAR_BIT * sizeof(((PGconn){0}).allowed_auth_methods),
+ "AUTH_REQ_MAX overflows the allowed_auth_methods bitmask");
+
/*
* Verify that the authentication request is expected, given the connection
* parameters. This is especially important when the client wishes to
@@ -839,6 +883,102 @@ static bool
check_expected_areq(AuthRequest areq, PGconn *conn)
{
bool result = true;
+ char *reason = NULL;
+
+ /*
+ * If the user required a specific auth method, or specified an allowed set,
+ * then reject all others here, and make sure the server actually completes
+ * an authentication exchange.
+ */
+ if (conn->require_auth)
+ {
+ switch (areq)
+ {
+ case AUTH_REQ_OK:
+ /*
+ * Check to make sure we've actually finished our exchange (or
+ * else that the user has allowed an authentication-less
+ * connection).
+ *
+ * If the user has allowed both SCRAM and unauthenticated
+ * (trust) connections, then this check will silently accept
+ * partial SCRAM exchanges, where a misbehaving server does not
+ * provide its verifier before sending an OK. This is consistent
+ * with historical behavior, but it may be a point to revisit in
+ * the future, since it could allow a server that doesn't know
+ * the user's password to silently harvest material for a brute
+ * force attack.
+ */
+ if (!conn->auth_required || conn->client_finished_auth)
+ break;
+
+ /*
+ * No explicit authentication request was made by the server --
+ * or perhaps it was made and not completed, in the case of
+ * SCRAM -- but there is one special case to check. If the user
+ * allowed "gss", then a GSS-encrypted channel also satisfies
+ * the check.
+ */
+#ifdef ENABLE_GSS
+ if (auth_allowed(conn, AUTH_REQ_GSS) && conn->gssenc)
+ {
+ /*
+ * If implicit GSS auth has already been performed via GSS
+ * encryption, we don't need to have performed an
+ * AUTH_REQ_GSS exchange. This allows require_auth=gss to be
+ * combined with gssencmode, since there won't be an
+ * explicit authentication request in that case.
+ */
+ }
+ else
+#endif
+ {
+ reason = libpq_gettext("server did not complete authentication"),
+ result = false;
+ }
+
+ break;
+
+ case AUTH_REQ_PASSWORD:
+ case AUTH_REQ_MD5:
+ case AUTH_REQ_GSS:
+ case AUTH_REQ_SSPI:
+ case AUTH_REQ_GSS_CONT:
+ case AUTH_REQ_SASL:
+ case AUTH_REQ_SASL_CONT:
+ case AUTH_REQ_SASL_FIN:
+ /*
+ * We don't handle these with the default case, to avoid
+ * bit-shifting past the end of the allowed_auth_methods mask if
+ * the server sends an unexpected AuthRequest.
+ */
+ result = auth_allowed(conn, areq);
+ break;
+
+ default:
+ result = false;
+ break;
+ }
+ }
+
+ if (!result)
+ {
+ if (reason)
+ {
+ appendPQExpBuffer(&conn->errorMessage,
+ libpq_gettext("auth method \"%s\" requirement failed: %s\n"),
+ conn->require_auth, reason);
+ }
+ else
+ {
+ appendPQExpBuffer(&conn->errorMessage,
+ libpq_gettext("auth method \"%s\" required, but server requested %s\n"),
+ conn->require_auth,
+ auth_description(areq));
+ }
+
+ return result;
+ }
/*
* When channel_binding=require, we must protect against two cases: (1) we
@@ -1040,6 +1180,9 @@ pg_fe_sendauth(AuthRequest areq, int payloadlen, PGconn *conn)
"fe_sendauth: error sending password authentication\n");
return STATUS_ERROR;
}
+
+ /* We expect no further authentication requests. */
+ conn->client_finished_auth = true;
break;
}
diff --git a/src/interfaces/libpq/fe-connect.c b/src/interfaces/libpq/fe-connect.c
index 746e9b4f1e..40f571fadb 100644
--- a/src/interfaces/libpq/fe-connect.c
+++ b/src/interfaces/libpq/fe-connect.c
@@ -307,6 +307,10 @@ static const internalPQconninfoOption PQconninfoOptions[] = {
"Require-Peer", "", 10,
offsetof(struct pg_conn, requirepeer)},
+ {"require_auth", "PGREQUIREAUTH", NULL, NULL,
+ "Require-Auth", "", 14, /* sizeof("scram-sha-256") == 14 */
+ offsetof(struct pg_conn, require_auth)},
+
{"ssl_min_protocol_version", "PGSSLMINPROTOCOLVERSION", "TLSv1.2", NULL,
"SSL-Minimum-Protocol-Version", "", 8, /* sizeof("TLSv1.x") == 8 */
offsetof(struct pg_conn, ssl_min_protocol_version)},
@@ -1240,6 +1244,166 @@ connectOptions2(PGconn *conn)
}
}
+ /*
+ * parse and validate require_auth option
+ */
+ if (conn->require_auth)
+ {
+ char *s = conn->require_auth;
+ bool first, more;
+ bool negated = false;
+
+ /*
+ * By default, start from an empty set of allowed options and add to it.
+ */
+ conn->auth_required = true;
+ conn->allowed_auth_methods = 0;
+
+ for (first = true, more = true; more; first = false)
+ {
+ char *method, *part;
+ uint32 bits;
+
+ part = parse_comma_separated_list(&s, &more);
+ if (part == NULL)
+ goto oom_error;
+
+ /*
+ * Check for negation, e.g. '!password'. If one element is negated,
+ * they all have to be.
+ */
+ method = part;
+ if (*method == '!')
+ {
+ if (first)
+ {
+ /*
+ * Switch to a permissive set of allowed options, and
+ * subtract from it.
+ */
+ conn->auth_required = false;
+ conn->allowed_auth_methods = -1;
+ }
+ else if (!negated)
+ {
+ conn->status = CONNECTION_BAD;
+ appendPQExpBuffer(&conn->errorMessage,
+ libpq_gettext("negative require_auth method \"%s\" cannot be mixed with non-negative methods"),
+ method);
+
+ free(part);
+ return false;
+ }
+
+ negated = true;
+ method++;
+ }
+ else if (negated)
+ {
+ conn->status = CONNECTION_BAD;
+ appendPQExpBuffer(&conn->errorMessage,
+ libpq_gettext("require_auth method \"%s\" cannot be mixed with negative methods"),
+ method);
+
+ free(part);
+ return false;
+ }
+
+ if (strcmp(method, "password") == 0)
+ {
+ bits = (1 << AUTH_REQ_PASSWORD);
+ }
+ else if (strcmp(method, "md5") == 0)
+ {
+ bits = (1 << AUTH_REQ_MD5);
+ }
+ else if (strcmp(method, "gss") == 0)
+ {
+ bits = (1 << AUTH_REQ_GSS);
+ bits |= (1 << AUTH_REQ_GSS_CONT);
+ }
+ else if (strcmp(method, "sspi") == 0)
+ {
+ bits = (1 << AUTH_REQ_SSPI);
+ bits |= (1 << AUTH_REQ_GSS_CONT);
+ }
+ else if (strcmp(method, "scram-sha-256") == 0)
+ {
+ /* This currently assumes that SCRAM is the only SASL method. */
+ bits = (1 << AUTH_REQ_SASL);
+ bits |= (1 << AUTH_REQ_SASL_CONT);
+ bits |= (1 << AUTH_REQ_SASL_FIN);
+ }
+ else if (strcmp(method, "none") == 0)
+ {
+ /*
+ * Special case: let the user explicitly allow (or disallow)
+ * connections where the server does not send an explicit
+ * authentication challenge, such as "trust" and "cert" auth.
+ */
+ if (negated) /* "!none" */
+ {
+ if (conn->auth_required)
+ goto duplicate;
+
+ conn->auth_required = true;
+ }
+ else /* "none" */
+ {
+ if (!conn->auth_required)
+ goto duplicate;
+
+ conn->auth_required = false;
+ }
+
+ free(part);
+ continue; /* avoid the bitmask manipulation below */
+ }
+ else
+ {
+ conn->status = CONNECTION_BAD;
+ appendPQExpBuffer(&conn->errorMessage,
+ libpq_gettext("invalid require_auth method: \"%s\""),
+ method);
+
+ free(part);
+ return false;
+ }
+
+ /* Update the bitmask. */
+ if (negated)
+ {
+ if ((conn->allowed_auth_methods & bits) == 0)
+ goto duplicate;
+
+ conn->allowed_auth_methods &= ~bits;
+ }
+ else
+ {
+ if ((conn->allowed_auth_methods & bits) == bits)
+ goto duplicate;
+
+ conn->allowed_auth_methods |= bits;
+ }
+
+ free(part);
+ continue;
+
+duplicate:
+ /*
+ * A duplicated method probably indicates a typo in a setting where
+ * typos are extremely risky.
+ */
+ conn->status = CONNECTION_BAD;
+ appendPQExpBuffer(&conn->errorMessage,
+ libpq_gettext("require_auth method \"%s\" is specified more than once"),
+ part);
+
+ free(part);
+ return false;
+ }
+ }
+
/*
* validate channel_binding option
*/
diff --git a/src/interfaces/libpq/fe-secure-openssl.c b/src/interfaces/libpq/fe-secure-openssl.c
index aea4661736..957c080356 100644
--- a/src/interfaces/libpq/fe-secure-openssl.c
+++ b/src/interfaces/libpq/fe-secure-openssl.c
@@ -475,7 +475,6 @@ verify_cb(int ok, X509_STORE_CTX *ctx)
return ok;
}
-
/*
* OpenSSL-specific wrapper around
* pq_verify_peer_name_matches_certificate_name(), converting the ASN1_STRING
diff --git a/src/interfaces/libpq/libpq-int.h b/src/interfaces/libpq/libpq-int.h
index c75ed63a2c..e4d88e22a1 100644
--- a/src/interfaces/libpq/libpq-int.h
+++ b/src/interfaces/libpq/libpq-int.h
@@ -396,6 +396,7 @@ struct pg_conn
char *ssl_min_protocol_version; /* minimum TLS protocol version */
char *ssl_max_protocol_version; /* maximum TLS protocol version */
char *target_session_attrs; /* desired session properties */
+ char *require_auth; /* name of the expected auth method */
/* Optional file to write trace info to */
FILE *Pfdebug;
@@ -457,6 +458,9 @@ struct pg_conn
bool write_failed; /* have we had a write failure on sock? */
char *write_err_msg; /* write error message, or NULL if OOM */
+ bool auth_required; /* require an authentication challenge from the server? */
+ uint32 allowed_auth_methods; /* bitmask of acceptable AuthRequest codes */
+
/* Transient state needed while establishing connection */
PGTargetServerType target_server_type; /* desired session properties */
bool try_next_addr; /* time to advance to next address/host? */
@@ -512,6 +516,9 @@ struct pg_conn
bool error_result; /* do we need to make an ERROR result? */
PGresult *next_result; /* next result (used in single-row mode) */
+ bool client_finished_auth; /* have we finished our half of the
+ * authentication exchange? */
+
/* Assorted state for SASL, SSL, GSS, etc */
const pg_fe_sasl_mech *sasl;
void *sasl_state;
diff --git a/src/test/authentication/t/001_password.pl b/src/test/authentication/t/001_password.pl
index 3e3079c824..473a93d6db 100644
--- a/src/test/authentication/t/001_password.pl
+++ b/src/test/authentication/t/001_password.pl
@@ -82,6 +82,74 @@ test_role($node, 'scram_role', 'trust', 0,
test_role($node, 'md5_role', 'trust', 0,
log_unlike => [qr/connection authenticated:/]);
+# All positive require_auth options should fail...
+$node->connect_fails("user=scram_role require_auth=gss",
+ "GSS authentication can be required: fails with trust auth",
+ expected_stderr => qr/server did not complete authentication/);
+$node->connect_fails("user=scram_role require_auth=sspi",
+ "SSPI authentication can be required: fails with trust auth",
+ expected_stderr => qr/server did not complete authentication/);
+$node->connect_fails("user=scram_role require_auth=password",
+ "password authentication can be required: fails with trust auth",
+ expected_stderr => qr/server did not complete authentication/);
+$node->connect_fails("user=scram_role require_auth=md5",
+ "md5 authentication can be required: fails with trust auth",
+ expected_stderr => qr/server did not complete authentication/);
+$node->connect_fails("user=scram_role require_auth=scram-sha-256",
+ "SCRAM authentication can be required: fails with trust auth",
+ expected_stderr => qr/server did not complete authentication/);
+$node->connect_fails("user=scram_role require_auth=password,scram-sha-256",
+ "multiple authentication types can be required: fails with trust auth",
+ expected_stderr => qr/server did not complete authentication/);
+
+# ...and negative require_auth options should succeed.
+$node->connect_ok("user=scram_role require_auth=!gss",
+ "GSS authentication can be forbidden: succeeds with trust auth");
+$node->connect_ok("user=scram_role require_auth=!sspi",
+ "SSPI authentication can be forbidden: succeeds with trust auth");
+$node->connect_ok("user=scram_role require_auth=!password",
+ "password authentication can be forbidden: succeeds with trust auth");
+$node->connect_ok("user=scram_role require_auth=!md5",
+ "md5 authentication can be forbidden: succeeds with trust auth");
+$node->connect_ok("user=scram_role require_auth=!scram-sha-256",
+ "SCRAM authentication can be forbidden: succeeds with trust auth");
+$node->connect_ok("user=scram_role require_auth=!password,!scram-sha-256",
+ "multiple authentication types can be forbidden: succeeds with trust auth");
+
+# require_auth=[!]none should interact correctly with trust auth.
+$node->connect_ok("user=scram_role require_auth=none",
+ "all authentication can be forbidden: succeeds with trust auth");
+$node->connect_fails("user=scram_role require_auth=!none",
+ "any authentication can be required: fails with trust auth",
+ expected_stderr => qr/server did not complete authentication/);
+
+# Negative and positive require_auth options can't be mixed.
+$node->connect_fails("user=scram_role require_auth=scram-sha-256,!md5",
+ "negative require_auth methods can't be mixed with positive",
+ expected_stderr => qr/negative require_auth method "!md5" cannot be mixed with non-negative methods/);
+$node->connect_fails("user=scram_role require_auth=!password,scram-sha-256",
+ "positive require_auth methods can't be mixed with negative",
+ expected_stderr => qr/require_auth method "scram-sha-256" cannot be mixed with negative methods/);
+
+# require_auth methods can't be duplicated.
+$node->connect_fails("user=scram_role require_auth=password,md5,password",
+ "require_auth methods can't be duplicated: positive case",
+ expected_stderr => qr/require_auth method "password" is specified more than once/);
+$node->connect_fails("user=scram_role require_auth=!password,!md5,!password",
+ "require_auth methods can't be duplicated: negative case",
+ expected_stderr => qr/require_auth method "!password" is specified more than once/);
+$node->connect_fails("user=scram_role require_auth=none,md5,none",
+ "require_auth methods can't be duplicated: none case",
+ expected_stderr => qr/require_auth method "none" is specified more than once/);
+$node->connect_fails("user=scram_role require_auth=!none,!md5,!none",
+ "require_auth methods can't be duplicated: !none case",
+ expected_stderr => qr/require_auth method "!none" is specified more than once/);
+
+# Unknown require_auth methods are caught.
+$node->connect_fails("user=scram_role require_auth=none,abcdefg",
+ "unknown require_auth methods are rejected",
+ expected_stderr => qr/invalid require_auth method: "abcdefg"/);
+
# For plain "password" method, all users should also be able to connect.
reset_pg_hba($node, 'password');
test_role($node, 'scram_role', 'password', 0,
@@ -91,6 +159,33 @@ test_role($node, 'md5_role', 'password', 0,
log_like =>
[qr/connection authenticated: identity="md5_role" method=password/]);
+# require_auth should succeed with a plaintext password...
+$node->connect_ok("user=scram_role require_auth=password",
+ "password authentication can be required: works with password auth");
+$node->connect_ok("user=scram_role require_auth=!none",
+ "any authentication can be required: works with password auth");
+$node->connect_ok("user=scram_role require_auth=scram-sha-256,password,md5",
+ "multiple authentication types can be required: works with password auth");
+
+# ...fail for other auth types...
+$node->connect_fails("user=scram_role require_auth=md5",
+ "md5 authentication can be required: fails with password auth",
+ expected_stderr => qr/server requested a cleartext password/);
+$node->connect_fails("user=scram_role require_auth=scram-sha-256",
+ "SCRAM authentication can be required: fails with password auth",
+ expected_stderr => qr/server requested a cleartext password/);
+$node->connect_fails("user=scram_role require_auth=none",
+ "all authentication can be forbidden: fails with password auth",
+ expected_stderr => qr/server requested a cleartext password/);
+
+# ...and allow password authentication to be prohibited.
+$node->connect_fails("user=scram_role require_auth=!password",
+ "password authentication can be forbidden: fails with password auth",
+ expected_stderr => qr/server requested a cleartext password/);
+$node->connect_fails("user=scram_role require_auth=!password,!md5,!scram-sha-256",
+ "multiple authentication types can be forbidden: fails with password auth",
+ expected_stderr => qr/server requested a cleartext password/);
+
# For "scram-sha-256" method, user "scram_role" should be able to connect.
reset_pg_hba($node, 'scram-sha-256');
test_role(
@@ -104,6 +199,33 @@ test_role(
test_role($node, 'md5_role', 'scram-sha-256', 2,
log_unlike => [qr/connection authenticated:/]);
+# require_auth should succeed with SCRAM...
+$node->connect_ok("user=scram_role require_auth=scram-sha-256",
+ "SCRAM authentication can be required: works with SCRAM auth");
+$node->connect_ok("user=scram_role require_auth=!none",
+ "any authentication can be required: works with SCRAM auth");
+$node->connect_ok("user=scram_role require_auth=password,scram-sha-256,md5",
+ "multiple authentication types can be required: works with SCRAM auth");
+
+# ...fail for other auth types...
+$node->connect_fails("user=scram_role require_auth=password",
+ "password authentication can be required: fails with SCRAM auth",
+ expected_stderr => qr/server requested SASL authentication/);
+$node->connect_fails("user=scram_role require_auth=md5",
+ "md5 authentication can be required: fails with SCRAM auth",
+ expected_stderr => qr/server requested SASL authentication/);
+$node->connect_fails("user=scram_role require_auth=none",
+ "all authentication can be forbidden: fails with SCRAM auth",
+ expected_stderr => qr/server requested SASL authentication/);
+
+# ...and allow SCRAM authentication to be prohibited.
+$node->connect_fails("user=scram_role require_auth=!scram-sha-256",
+ "SCRAM authentication can be forbidden: fails with SCRAM auth",
+ expected_stderr => qr/server requested SASL authentication/);
+$node->connect_fails("user=scram_role require_auth=!password,!md5,!scram-sha-256",
+ "multiple authentication types can be forbidden: fails with SCRAM auth",
+ expected_stderr => qr/server requested SASL authentication/);
+
# Test that bad passwords are rejected.
$ENV{"PGPASSWORD"} = 'badpass';
test_role($node, 'scram_role', 'scram-sha-256', 2,
@@ -120,6 +242,33 @@ test_role($node, 'md5_role', 'md5', 0,
log_like =>
[qr/connection authenticated: identity="md5_role" method=md5/]);
+# require_auth should succeed with MD5...
+$node->connect_ok("user=md5_role require_auth=md5",
+ "MD5 authentication can be required: works with MD5 auth");
+$node->connect_ok("user=md5_role require_auth=!none",
+ "any authentication can be required: works with MD5 auth");
+$node->connect_ok("user=md5_role require_auth=md5,scram-sha-256,password",
+ "multiple authentication types can be required: works with MD5 auth");
+
+# ...fail for other auth types...
+$node->connect_fails("user=md5_role require_auth=password",
+ "password authentication can be required: fails with MD5 auth",
+ expected_stderr => qr/server requested a hashed password/);
+$node->connect_fails("user=md5_role require_auth=scram-sha-256",
+ "SCRAM authentication can be required: fails with MD5 auth",
+ expected_stderr => qr/server requested a hashed password/);
+$node->connect_fails("user=md5_role require_auth=none",
+ "all authentication can be forbidden: fails with MD5 auth",
+ expected_stderr => qr/server requested a hashed password/);
+
+# ...and allow MD5 authentication to be prohibited.
+$node->connect_fails("user=md5_role require_auth=!md5",
+ "password authentication can be forbidden: fails with MD5 auth",
+ expected_stderr => qr/server requested a hashed password/);
+$node->connect_fails("user=md5_role require_auth=!password,!md5,!scram-sha-256",
+ "multiple authentication types can be forbidden: fails with MD5 auth",
+ expected_stderr => qr/server requested a hashed password/);
+
# Tests for channel binding without SSL.
# Using the password authentication method; channel binding can't work
reset_pg_hba($node, 'password');
diff --git a/src/test/kerberos/t/001_auth.pl b/src/test/kerberos/t/001_auth.pl
index 47169a1d1e..054df71541 100644
--- a/src/test/kerberos/t/001_auth.pl
+++ b/src/test/kerberos/t/001_auth.pl
@@ -311,6 +311,24 @@ test_query(
'gssencmode=require',
'sending 100K lines works');
+# require_auth=gss should succeed...
+$node->connect_ok(
+ $node->connstr('postgres') . " user=test1 host=$host hostaddr=$hostaddr gssencmode=disable require_auth=gss",
+ "GSS authentication can be requested: works with GSS auth without encryption");
+$node->connect_ok(
+ $node->connstr('postgres') . " user=test1 host=$host hostaddr=$hostaddr gssencmode=require require_auth=gss",
+ "GSS authentication can be requested: works with GSS auth with encryption");
+
+# ...and require_auth=sspi should fail.
+$node->connect_fails(
+ $node->connstr('postgres') . " user=test1 host=$host hostaddr=$hostaddr gssencmode=disable require_auth=sspi",
+ "SSPI authentication can be requested: fails with GSS auth without encryption",
+ expected_stderr => qr/server requested GSSAPI authentication/);
+$node->connect_fails(
+ $node->connstr('postgres') . " user=test1 host=$host hostaddr=$hostaddr gssencmode=require require_auth=sspi",
+ "SSPI authentication can be requested: fails with GSS auth with encryption",
+ expected_stderr => qr/server did not complete authentication/);
+
unlink($node->data_dir . '/pg_hba.conf');
$node->append_conf('pg_hba.conf',
qq{hostgssenc all all $hostaddr/32 gss map=mymap});
@@ -339,6 +357,14 @@ test_access(
test_access($node, 'test1', 'SELECT true', 2, 'gssencmode=disable',
'fails with GSS encryption disabled and hostgssenc hba');
+# require_auth=gss should succeed.
+$node->connect_ok(
+ $node->connstr('postgres') . " user=test1 host=$host hostaddr=$hostaddr gssencmode=require require_auth=gss",
+ "GSS authentication can be requested: works with GSS encryption");
+$node->connect_ok(
+ $node->connstr('postgres') . " user=test1 host=$host hostaddr=$hostaddr gssencmode=require require_auth=gss,scram-sha-256",
+ "multiple authentication types can be requested: works with GSS encryption");
+
unlink($node->data_dir . '/pg_hba.conf');
$node->append_conf('pg_hba.conf',
qq{hostnogssenc all all $hostaddr/32 gss map=mymap});
diff --git a/src/test/ldap/t/001_auth.pl b/src/test/ldap/t/001_auth.pl
index 2f064f6944..25483e50cc 100644
--- a/src/test/ldap/t/001_auth.pl
+++ b/src/test/ldap/t/001_auth.pl
@@ -220,6 +220,12 @@ test_access(
qr/connection authenticated: identity="uid=test1,dc=example,dc=net" method=ldap/
],);
+# require_auth=password should complete successfully; other methods should fail.
+$node->connect_ok("user=test1 require_auth=password",
+ "password authentication can be required: works with ldap auth");
+$node->connect_fails("user=test1 require_auth=scram-sha-256",
+ "SCRAM authentication can be required: fails with ldap auth");
+
note "search+bind";
unlink($node->data_dir . '/pg_hba.conf');
diff --git a/src/test/ssl/t/002_scram.pl b/src/test/ssl/t/002_scram.pl
index deaa4aa086..cf61bc7d0d 100644
--- a/src/test/ssl/t/002_scram.pl
+++ b/src/test/ssl/t/002_scram.pl
@@ -136,4 +136,29 @@ $node->connect_ok(
qr/connection authenticated: identity="ssltestuser" method=scram-sha-256/
]);
+# channel_binding should continue to function independently of require_auth.
+$node->connect_ok("$common_connstr user=ssltestuser channel_binding=disable require_auth=scram-sha-256",
+ "SCRAM with SSL, channel_binding=disable, and require_auth=scram-sha-256");
+$node->connect_fails(
+ "$common_connstr user=md5testuser require_auth=md5 channel_binding=require",
+ "channel_binding can fail even when require_auth succeeds",
+ expected_stderr =>
+ qr/channel binding required but not supported by server's authentication request/
+);
+if ($supports_tls_server_end_point)
+{
+ $node->connect_ok(
+ "$common_connstr user=ssltestuser channel_binding=require require_auth=scram-sha-256",
+ "SCRAM with SSL, channel_binding=require, and require_auth=scram-sha-256");
+}
+else
+{
+ $node->connect_fails(
+ "$common_connstr user=ssltestuser channel_binding=require require_auth=scram-sha-256",
+ "SCRAM with SSL, channel_binding=require, and require_auth=scram-sha-256",
+ expected_stderr =>
+ qr/channel binding is required, but server did not offer an authentication method that supports channel binding/
+ );
+}
+
done_testing();
--
2.25.1
From ff3a153fa31bd98e19c5f6c77aaa54b0f7173d8e Mon Sep 17 00:00:00 2001
From: Jacob Champion <jchamp...@timescale.com>
Date: Fri, 24 Jun 2022 15:40:42 -0700
Subject: [PATCH v9 2/2] Add sslcertmode option for client certificates
The sslcertmode option controls whether the server is allowed and/or
required to request a certificate from the client. There are three
modes:
- "allow" is the default and follows the current behavior -- a
configured sslcert is sent if the server requests one (which, with
the current implementation, will happen whenever TLS is negotiated).
- "disable" causes the client to refuse to send a client certificate
even if an sslcert is configured.
- "require" causes the client to fail if a client certificate is never
sent and the server opens a connection anyway. This doesn't add any
additional security, since there is no guarantee that the server is
validating the certificate correctly, but it may help troubleshoot
more complicated TLS setups.
sslcertmode=require needs the OpenSSL implementation to support
SSL_CTX_set_cert_cb(). Notably, LibreSSL does not.
---
configure | 11 ++---
configure.ac | 4 +-
doc/src/sgml/libpq.sgml | 54 +++++++++++++++++++++++
src/include/pg_config.h.in | 3 ++
src/interfaces/libpq/fe-auth.c | 21 +++++++++
src/interfaces/libpq/fe-connect.c | 55 ++++++++++++++++++++++++
src/interfaces/libpq/fe-secure-openssl.c | 40 ++++++++++++++++-
src/interfaces/libpq/libpq-int.h | 3 ++
src/test/ssl/t/001_ssltests.pl | 43 ++++++++++++++++++
src/tools/msvc/Solution.pm | 8 ++++
10 files changed, 234 insertions(+), 8 deletions(-)
diff --git a/configure b/configure
index 1caca21b62..94171d4f54 100755
--- a/configure
+++ b/configure
@@ -12904,13 +12904,14 @@ else
fi
fi
- # Function introduced in OpenSSL 1.0.2.
- for ac_func in X509_get_signature_nid
+ # Functions introduced in OpenSSL 1.0.2. LibreSSL doesn't have all of these.
+ for ac_func in X509_get_signature_nid SSL_CTX_set_cert_cb
do :
- ac_fn_c_check_func "$LINENO" "X509_get_signature_nid" "ac_cv_func_X509_get_signature_nid"
-if test "x$ac_cv_func_X509_get_signature_nid" = xyes; then :
+ as_ac_var=`$as_echo "ac_cv_func_$ac_func" | $as_tr_sh`
+ac_fn_c_check_func "$LINENO" "$ac_func" "$as_ac_var"
+if eval test \"x\$"$as_ac_var"\" = x"yes"; then :
cat >>confdefs.h <<_ACEOF
-#define HAVE_X509_GET_SIGNATURE_NID 1
+#define `$as_echo "HAVE_$ac_func" | $as_tr_cpp` 1
_ACEOF
fi
diff --git a/configure.ac b/configure.ac
index 10fa55dd15..1150a21b1f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1350,8 +1350,8 @@ if test "$with_ssl" = openssl ; then
AC_SEARCH_LIBS(CRYPTO_new_ex_data, [eay32 crypto], [], [AC_MSG_ERROR([library 'eay32' or 'crypto' is required for OpenSSL])])
AC_SEARCH_LIBS(SSL_new, [ssleay32 ssl], [], [AC_MSG_ERROR([library 'ssleay32' or 'ssl' is required for OpenSSL])])
fi
- # Function introduced in OpenSSL 1.0.2.
- AC_CHECK_FUNCS([X509_get_signature_nid])
+ # Functions introduced in OpenSSL 1.0.2. LibreSSL doesn't have all of these.
+ AC_CHECK_FUNCS([X509_get_signature_nid SSL_CTX_set_cert_cb])
# Functions introduced in OpenSSL 1.1.0. We used to check for
# OPENSSL_VERSION_NUMBER, but that didn't work with 1.1.0, because LibreSSL
# defines OPENSSL_VERSION_NUMBER to claim version 2.0.0, even though it
diff --git a/doc/src/sgml/libpq.sgml b/doc/src/sgml/libpq.sgml
index 1d6c02058e..821078ea6a 100644
--- a/doc/src/sgml/libpq.sgml
+++ b/doc/src/sgml/libpq.sgml
@@ -1810,6 +1810,50 @@ postgresql://%2Fvar%2Flib%2Fpostgresql/dbname
</listitem>
</varlistentry>
+ <varlistentry id="libpq-connect-sslcertmode" xreflabel="sslcertmode">
+ <term><literal>sslcertmode</literal></term>
+ <listitem>
+ <para>
+ This option determines whether a client certificate may be sent to the
+ server, and whether the server is required to request one. There are
+ three modes:
+
+ <variablelist>
+ <varlistentry>
+ <term><literal>disable</literal></term>
+ <listitem>
+ <para>
+ a client certificate is never sent, even if one is provided via
+ <xref linkend="libpq-connect-sslcert" />
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><literal>allow</literal> (default)</term>
+ <listitem>
+ <para>
+ a certificate may be sent, if the server requests one and it has
+ been provided via <literal>sslcert</literal>
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><literal>require</literal></term>
+ <listitem>
+ <para>
+ the server <emphasis>must</emphasis> request a certificate. The
+ connection will fail if the server authenticates the client despite
+ not requesting or receiving one.
+ </para>
+ </listitem>
+ </varlistentry>
+ </variablelist>
+ </para>
+ </listitem>
+ </varlistentry>
+
<varlistentry id="libpq-connect-sslrootcert" xreflabel="sslrootcert">
<term><literal>sslrootcert</literal></term>
<listitem>
@@ -7968,6 +8012,16 @@ myEventProc(PGEventId evtId, void *evtInfo, void *passThrough)
</para>
</listitem>
+ <listitem>
+ <para>
+ <indexterm>
+ <primary><envar>PGSSLCERTMODE</envar></primary>
+ </indexterm>
+ <envar>PGSSLCERTMODE</envar> behaves the same as the <xref
+ linkend="libpq-connect-sslcertmode"/> connection parameter.
+ </para>
+ </listitem>
+
<listitem>
<para>
<indexterm>
diff --git a/src/include/pg_config.h.in b/src/include/pg_config.h.in
index c5a80b829e..08382e868b 100644
--- a/src/include/pg_config.h.in
+++ b/src/include/pg_config.h.in
@@ -397,6 +397,9 @@
/* Define to 1 if you have spinlocks. */
#undef HAVE_SPINLOCKS
+/* Define to 1 if you have the `SSL_CTX_set_cert_cb' function. */
+#undef HAVE_SSL_CTX_SET_CERT_CB
+
/* Define to 1 if stdbool.h conforms to C99. */
#undef HAVE_STDBOOL_H
diff --git a/src/interfaces/libpq/fe-auth.c b/src/interfaces/libpq/fe-auth.c
index c95deffd2b..793888d30f 100644
--- a/src/interfaces/libpq/fe-auth.c
+++ b/src/interfaces/libpq/fe-auth.c
@@ -885,6 +885,27 @@ check_expected_areq(AuthRequest areq, PGconn *conn)
bool result = true;
char *reason = NULL;
+ if (conn->sslcertmode[0] == 'r' /* require */
+ && areq == AUTH_REQ_OK)
+ {
+ /*
+ * Trade off a little bit of complexity to try to get these error
+ * messages as precise as possible.
+ */
+ if (!conn->ssl_cert_requested)
+ {
+ appendPQExpBufferStr(&conn->errorMessage,
+ libpq_gettext("server did not request a certificate"));
+ return false;
+ }
+ else if (!conn->ssl_cert_sent)
+ {
+ appendPQExpBufferStr(&conn->errorMessage,
+ libpq_gettext("server accepted connection without a valid certificate"));
+ return false;
+ }
+ }
+
/*
* If the user required a specific auth method, or specified an allowed set,
* then reject all others here, and make sure the server actually completes
diff --git a/src/interfaces/libpq/fe-connect.c b/src/interfaces/libpq/fe-connect.c
index 40f571fadb..eaca8cee1f 100644
--- a/src/interfaces/libpq/fe-connect.c
+++ b/src/interfaces/libpq/fe-connect.c
@@ -125,8 +125,10 @@ static int ldapServiceLookup(const char *purl, PQconninfoOption *options,
#define DefaultTargetSessionAttrs "any"
#ifdef USE_SSL
#define DefaultSSLMode "prefer"
+#define DefaultSSLCertMode "allow"
#else
#define DefaultSSLMode "disable"
+#define DefaultSSLCertMode "disable"
#endif
#ifdef ENABLE_GSS
#include "fe-gssapi-common.h"
@@ -283,6 +285,10 @@ static const internalPQconninfoOption PQconninfoOptions[] = {
"SSL-Client-Key", "", 64,
offsetof(struct pg_conn, sslkey)},
+ {"sslcertmode", "PGSSLCERTMODE", NULL, NULL,
+ "SSL-Client-Cert-Mode", "", 8, /* sizeof("disable") == 8 */
+ offsetof(struct pg_conn, sslcertmode)},
+
{"sslpassword", NULL, NULL, NULL,
"SSL-Client-Key-Password", "*", 20,
offsetof(struct pg_conn, sslpassword)},
@@ -1514,6 +1520,55 @@ duplicate:
return false;
}
+ /*
+ * validate sslcertmode option
+ */
+ if (conn->sslcertmode)
+ {
+ if (strcmp(conn->sslcertmode, "disable") != 0 &&
+ strcmp(conn->sslcertmode, "allow") != 0 &&
+ strcmp(conn->sslcertmode, "require") != 0)
+ {
+ conn->status = CONNECTION_BAD;
+ appendPQExpBuffer(&conn->errorMessage,
+ libpq_gettext("invalid %s value: \"%s\"\n"),
+ "sslcertmode",
+ conn->sslcertmode);
+ return false;
+ }
+#ifndef USE_SSL
+ if (strcmp(conn->sslcertmode, "require") == 0)
+ {
+ conn->status = CONNECTION_BAD;
+ appendPQExpBuffer(&conn->errorMessage,
+ libpq_gettext("sslcertmode value \"%s\" invalid when SSL support is not compiled in\n"),
+ conn->sslcertmode);
+ return false;
+ }
+#endif
+#ifndef HAVE_SSL_CTX_SET_CERT_CB
+ /*
+ * Without a certificate callback, the current implementation can't
+ * figure out if a certficate was actually requested, so "require" is
+ * useless.
+ */
+ if (strcmp(conn->sslcertmode, "require") == 0)
+ {
+ conn->status = CONNECTION_BAD;
+ appendPQExpBuffer(&conn->errorMessage,
+ libpq_gettext("sslcertmode value \"%s\" is not supported (check OpenSSL version)\n"),
+ conn->sslcertmode);
+ return false;
+ }
+#endif
+ }
+ else
+ {
+ conn->sslcertmode = strdup(DefaultSSLCertMode);
+ if (!conn->sslcertmode)
+ goto oom_error;
+ }
+
/*
* validate gssencmode option
*/
diff --git a/src/interfaces/libpq/fe-secure-openssl.c b/src/interfaces/libpq/fe-secure-openssl.c
index 957c080356..10d65c966f 100644
--- a/src/interfaces/libpq/fe-secure-openssl.c
+++ b/src/interfaces/libpq/fe-secure-openssl.c
@@ -475,6 +475,34 @@ verify_cb(int ok, X509_STORE_CTX *ctx)
return ok;
}
+#ifdef HAVE_SSL_CTX_SET_CERT_CB
+/*
+ * Certificate selection callback
+ *
+ * This callback lets us choose the client certificate we send to the server
+ * after seeing its CertificateRequest. We only support sending a single
+ * hard-coded certificate via sslcert, so we don't actually set any certificates
+ * here; we just it to record whether or not the server has actually asked for
+ * one and whether we have one to send.
+ */
+static int
+cert_cb(SSL *ssl, void *arg)
+{
+ PGconn *conn = arg;
+ conn->ssl_cert_requested = true;
+
+ /* Do we have a certificate loaded to send back? */
+ if (SSL_get_certificate(ssl))
+ conn->ssl_cert_sent = true;
+
+ /*
+ * Tell OpenSSL that the callback succeeded; we're not required to actually
+ * make any changes to the SSL handle.
+ */
+ return 1;
+}
+#endif
+
/*
* OpenSSL-specific wrapper around
* pq_verify_peer_name_matches_certificate_name(), converting the ASN1_STRING
@@ -969,6 +997,11 @@ initialize_SSL(PGconn *conn)
SSL_CTX_set_default_passwd_cb_userdata(SSL_context, conn);
}
+#ifdef HAVE_SSL_CTX_SET_CERT_CB
+ /* Set up a certificate selection callback. */
+ SSL_CTX_set_cert_cb(SSL_context, cert_cb, conn);
+#endif
+
/* Disable old protocol versions */
SSL_CTX_set_options(SSL_context, SSL_OP_NO_SSLv2 | SSL_OP_NO_SSLv3);
@@ -1132,7 +1165,12 @@ initialize_SSL(PGconn *conn)
else
fnbuf[0] = '\0';
- if (fnbuf[0] == '\0')
+ if (conn->sslcertmode[0] == 'd') /* disable */
+ {
+ /* don't send a client cert even if we have one */
+ have_cert = false;
+ }
+ else if (fnbuf[0] == '\0')
{
/* no home directory, proceed without a client cert */
have_cert = false;
diff --git a/src/interfaces/libpq/libpq-int.h b/src/interfaces/libpq/libpq-int.h
index e4d88e22a1..ad6f8b78c6 100644
--- a/src/interfaces/libpq/libpq-int.h
+++ b/src/interfaces/libpq/libpq-int.h
@@ -384,6 +384,7 @@ struct pg_conn
char *sslkey; /* client key filename */
char *sslcert; /* client certificate filename */
char *sslpassword; /* client key file password */
+ char *sslcertmode; /* client cert mode (require,allow,disable) */
char *sslrootcert; /* root certificate filename */
char *sslcrl; /* certificate revocation list filename */
char *sslcrldir; /* certificate revocation list directory name */
@@ -525,6 +526,8 @@ struct pg_conn
/* SSL structures */
bool ssl_in_use;
+ bool ssl_cert_requested; /* Did the server ask us for a cert? */
+ bool ssl_cert_sent; /* Did we send one in reply? */
#ifdef USE_SSL
bool allow_ssl_try; /* Allowed to try SSL negotiation */
diff --git a/src/test/ssl/t/001_ssltests.pl b/src/test/ssl/t/001_ssltests.pl
index efe5634fff..49003ba1b7 100644
--- a/src/test/ssl/t/001_ssltests.pl
+++ b/src/test/ssl/t/001_ssltests.pl
@@ -42,6 +42,10 @@ my $SERVERHOSTADDR = '127.0.0.1';
# This is the pattern to use in pg_hba.conf to match incoming connections.
my $SERVERHOSTCIDR = '127.0.0.1/32';
+# Determine whether build supports sslcertmode=require.
+my $supports_sslcertmode_require =
+ check_pg_config("#define HAVE_SSL_CTX_SET_CERT_CB 1");
+
# Allocation of base connection string shared among multiple tests.
my $common_connstr;
@@ -191,6 +195,22 @@ $node->connect_ok(
"$common_connstr sslrootcert=ssl/both-cas-2.crt sslmode=verify-ca",
"cert root file that contains two certificates, order 2");
+# sslcertmode=allow and =disable should both work without a client certificate.
+$node->connect_ok(
+ "$common_connstr sslrootcert=ssl/root+server_ca.crt sslmode=require sslcertmode=disable",
+ "connect with sslcertmode=disable");
+$node->connect_ok(
+ "$common_connstr sslrootcert=ssl/root+server_ca.crt sslmode=require sslcertmode=allow",
+ "connect with sslcertmode=allow");
+
+# sslcertmode=require, however, should fail.
+$node->connect_fails(
+ "$common_connstr sslrootcert=ssl/root+server_ca.crt sslmode=require sslcertmode=require",
+ "connect with sslcertmode=require fails without a client certificate",
+ expected_stderr => $supports_sslcertmode_require
+ ? qr/server accepted connection without a valid certificate/
+ : qr/sslcertmode value "require" is not supported/);
+
# CRL tests
# Invalid CRL filename is the same as no CRL, succeeds
@@ -538,6 +558,29 @@ $node->connect_ok(
"certificate authorization succeeds with correct client cert in encrypted DER format"
);
+# correct client cert with required/allowed certificate authentication
+if ($supports_sslcertmode_require)
+{
+ $node->connect_ok(
+ "$common_connstr user=ssltestuser sslcertmode=require sslcert=ssl/client.crt "
+ . sslkey('client.key'),
+ "certificate authorization succeeds with sslcertmode=require"
+ );
+}
+$node->connect_ok(
+ "$common_connstr user=ssltestuser sslcertmode=allow sslcert=ssl/client.crt "
+ . sslkey('client.key'),
+ "certificate authorization succeeds with sslcertmode=allow"
+);
+
+# client cert isn't sent if certificate authentication is disabled
+$node->connect_fails(
+ "$common_connstr user=ssltestuser sslcertmode=disable sslcert=ssl/client.crt "
+ . sslkey('client.key'),
+ "certificate authorization fails with sslcertmode=disable",
+ expected_stderr => qr/connection requires a valid client certificate/
+);
+
# correct client cert in encrypted PEM with wrong password
$node->connect_fails(
"$common_connstr user=ssltestuser sslcert=ssl/client.crt "
diff --git a/src/tools/msvc/Solution.pm b/src/tools/msvc/Solution.pm
index c2acb58df0..ff6d6f9e35 100644
--- a/src/tools/msvc/Solution.pm
+++ b/src/tools/msvc/Solution.pm
@@ -328,6 +328,7 @@ sub GenerateFiles
HAVE_SETPROCTITLE_FAST => undef,
HAVE_SOCKLEN_T => 1,
HAVE_SPINLOCKS => 1,
+ HAVE_SSL_CTX_SET_CERT_CB => undef,
HAVE_STDBOOL_H => 1,
HAVE_STDINT_H => 1,
HAVE_STDLIB_H => 1,
@@ -489,6 +490,13 @@ sub GenerateFiles
my ($digit1, $digit2, $digit3) = $self->GetOpenSSLVersion();
+ if ( ($digit1 >= '3' && $digit2 >= '0' && $digit3 >= '0')
+ || ($digit1 >= '1' && $digit2 >= '1' && $digit3 >= '0')
+ || ($digit1 >= '1' && $digit2 >= '0' && $digit3 >= '2'))
+ {
+ $define{HAVE_SSL_CTX_SET_CERT_CB} = 1;
+ }
+
# More symbols are needed with OpenSSL 1.1.0 and above.
if ( ($digit1 >= '3' && $digit2 >= '0' && $digit3 >= '0')
|| ($digit1 >= '1' && $digit2 >= '1' && $digit3 >= '0'))
--
2.25.1
