Fix bugs in libpq's management of GSS encryption state.

GSS-related resources should be cleaned up in pqDropConnection,
not freePGconn, else the wrong things happen when resetting
a connection or trying to switch to a different server.
It's also critical to reset conn->gssenc there.

During connection setup, initialize conn->try_gss at the correct
place, else switching to a different server won't work right.

Remove now-redundant cleanup of GSS resources around one (and, for
some reason, only one) pqDropConnection call in connectDBStart.

Per report from Kyotaro Horiguchi that psql would freeze up,
rather than successfully resetting a GSS-encrypted connection
after a server restart.

This is YA oversight in commit b0b39f72b, so back-patch to v12.

Discussion: https://postgr.es/m/20200710.173803.435804731896516388.horikyota.ntt@gmail.com

diff --git a/src/interfaces/libpq/fe-connect.c b/src/interfaces/libpq/fe-connect.c
index 27c9bb46eea05b7c27a880277bbfb5a9ffc48ccf..7bee9dd2014c0198777ba754ec06bdfea89655de 100644 (file)
--- a/src/interfaces/libpq/fe-connect.c
+++ b/src/interfaces/libpq/fe-connect.c
@@ -477,6 +477,11 @@ pqDropConnection(PGconn *conn, bool flushInput)
    {
        OM_uint32   min_s;
 
+       if (conn->gcred != GSS_C_NO_CREDENTIAL)
+       {
+           gss_release_cred(&min_s, &conn->gcred);
+           conn->gcred = GSS_C_NO_CREDENTIAL;
+       }
        if (conn->gctx)
            gss_delete_sec_context(&min_s, &conn->gctx, GSS_C_NO_BUFFER);
        if (conn->gtarg_nam)
@@ -496,6 +501,7 @@ pqDropConnection(PGconn *conn, bool flushInput)
            free(conn->gss_ResultBuffer);
            conn->gss_ResultBuffer = NULL;
        }
+       conn->gssenc = false;
    }
 #endif
 #ifdef ENABLE_SSPI
@@ -2027,11 +2033,6 @@ connectDBStart(PGconn *conn)
     */
    resetPQExpBuffer(&conn->errorMessage);
 
-#ifdef ENABLE_GSS
-   if (conn->gssencmode[0] == 'd') /* "disable" */
-       conn->try_gss = false;
-#endif
-
    /*
     * Set up to try to connect to the first host.  (Setting whichhost = -1 is
     * a bit of a cheat, but PQconnectPoll will advance it to 0 before
@@ -2468,6 +2469,9 @@ keep_going:                       /* We will come back to here until there is
        conn->allow_ssl_try = (conn->sslmode[0] != 'd');    /* "disable" */
        conn->wait_ssl_try = (conn->sslmode[0] == 'a'); /* "allow" */
 #endif
+#ifdef ENABLE_GSS
+       conn->try_gss = (conn->gssencmode[0] != 'd');   /* "disable" */
+#endif
 
        reset_connection_state_machine = false;
        need_new_connection = true;
@@ -3349,12 +3353,8 @@ keep_going:                      /* We will come back to here until there is
                     */
                    if (conn->gssenc && conn->gssencmode[0] == 'p')
                    {
-                       OM_uint32   minor;
-
                        /* postmaster expects us to drop the connection */
                        conn->try_gss = false;
-                       conn->gssenc = false;
-                       gss_delete_sec_context(&minor, &conn->gctx, NULL);
                        pqDropConnection(conn, true);
                        conn->status = CONNECTION_NEEDED;
                        goto keep_going;
@@ -3906,9 +3906,6 @@ makeEmptyPGconn(void)
    conn->verbosity = PQERRORS_DEFAULT;
    conn->show_context = PQSHOW_CONTEXT_ERRORS;
    conn->sock = PGINVALID_SOCKET;
-#ifdef ENABLE_GSS
-   conn->try_gss = true;
-#endif
 
    /*
     * We try to send at least 8K at a time, which is the usual size of pipe
@@ -4065,22 +4062,6 @@ freePGconn(PGconn *conn)
        free(conn->gsslib);
    if (conn->connip)
        free(conn->connip);
-#ifdef ENABLE_GSS
-   if (conn->gcred != GSS_C_NO_CREDENTIAL)
-   {
-       OM_uint32   minor;
-
-       gss_release_cred(&minor, &conn->gcred);
-       conn->gcred = GSS_C_NO_CREDENTIAL;
-   }
-   if (conn->gctx)
-   {
-       OM_uint32   minor;
-
-       gss_delete_sec_context(&minor, &conn->gctx, GSS_C_NO_BUFFER);
-       conn->gctx = NULL;
-   }
-#endif
    /* Note that conn->Pfdebug is not ours to close or free */
    if (conn->last_query)
        free(conn->last_query);