tldap: Centralize connection rundown on error

Whenever send or recv return -1, we have to cancel all pending
requests and our transport stream is no longer usable: Discard it upon
such an error.

To avoid duplicate state, tldap_connection_ok() now looks at whether
we have a tstream_context around.

Bug: https://bugzilla.samba.org/show_bug.cgi?id=14465

Signed-off-by: Volker Lendecke <vl@samba.org>
Reviewed-by: Stefan Metzmacher <metze@samba.org>

diff --git a/source3/lib/tldap.c b/source3/lib/tldap.c
index 3bf58d0df3e6271d46a028bc15d2e57470de491c..de9f0c70ff117179251137b2c46c348b25605458 100644 (file)
--- a/source3/lib/tldap.c
+++ b/source3/lib/tldap.c
@@ -83,7 +83,6 @@ struct tldap_ctx_attribute {
 struct tldap_context {
        int ld_version;
        struct tstream_context *conn;
-       bool server_down;
        int msgid;
        struct tevent_queue *outgoing;
        struct tevent_req **pending;
@@ -186,10 +185,22 @@ struct tldap_context *tldap_context_create(TALLOC_CTX *mem_ctx, int fd)
 
 bool tldap_connection_ok(struct tldap_context *ld)
 {
+       int ret;
+
        if (ld == NULL) {
                return false;
        }
-       return !ld->server_down;
+
+       if (ld->conn == NULL) {
+               return false;
+       }
+
+       ret = tstream_pending_bytes(ld->conn);
+       if (ret == -1) {
+               return false;
+       }
+
+       return true;
 }
 
 static size_t tldap_pending_reqs(struct tldap_context *ld)
@@ -425,6 +436,43 @@ static bool tldap_push_controls(struct asn1_data *data,
        return asn1_pop_tag(data); /* ASN1_CONTEXT(0) */
 }
 
+#define tldap_context_disconnect(ld, status) \
+       _tldap_context_disconnect(ld, status, __location__)
+
+static void _tldap_context_disconnect(struct tldap_context *ld,
+                                     TLDAPRC status,
+                                     const char *location)
+{
+       if (ld->conn == NULL) {
+               /*
+                * We don't need to tldap_debug() on
+                * a potential 2nd run.
+                *
+                * The rest of the function would just
+                * be a noop for the 2nd run anyway.
+                */
+               return;
+       }
+
+       tldap_debug(ld, TLDAP_DEBUG_WARNING,
+                   "tldap_context_disconnect: %s at %s\n",
+                   tldap_rc2string(status),
+                   location);
+       tevent_queue_stop(ld->outgoing);
+       TALLOC_FREE(ld->read_req);
+       TALLOC_FREE(ld->conn);
+
+       while (talloc_array_length(ld->pending) > 0) {
+               struct tevent_req *req = NULL;
+               struct tldap_msg_state *state = NULL;
+
+               req = ld->pending[0];
+               state = tevent_req_data(req, struct tldap_msg_state);
+               tevent_req_defer_callback(req, state->ev);
+               tevent_req_ldap_error(req, status);
+       }
+}
+
 static void tldap_msg_sent(struct tevent_req *subreq);
 static void tldap_msg_received(struct tevent_req *subreq);
 
@@ -438,6 +486,7 @@ static struct tevent_req *tldap_msg_send(TALLOC_CTX *mem_ctx,
        struct tevent_req *req, *subreq;
        struct tldap_msg_state *state;
        DATA_BLOB blob;
+       bool ok;
 
        tldap_debug(ld, TLDAP_DEBUG_TRACE, "tldap_msg_send: sending msg %d\n",
                    id);
@@ -450,7 +499,8 @@ static struct tevent_req *tldap_msg_send(TALLOC_CTX *mem_ctx,
        state->ev = ev;
        state->id = id;
 
-       if (state->ld->server_down) {
+       ok = tldap_connection_ok(ld);
+       if (!ok) {
                tevent_req_ldap_error(req, TLDAP_SERVER_DOWN);
                return tevent_req_post(req, ev);
        }
@@ -582,7 +632,7 @@ static void tldap_msg_sent(struct tevent_req *subreq)
        nwritten = tstream_writev_queue_recv(subreq, &err);
        TALLOC_FREE(subreq);
        if (nwritten == -1) {
-               state->ld->server_down = true;
+               tldap_context_disconnect(state->ld, TLDAP_SERVER_DOWN);
                tevent_req_ldap_error(req, TLDAP_SERVER_DOWN);
                return;
        }
@@ -612,7 +662,7 @@ static void tldap_msg_received(struct tevent_req *subreq)
        ssize_t received;
        size_t num_pending;
        int i, err;
-       TLDAPRC status;
+       TLDAPRC status = TLDAP_PROTOCOL_ERROR;
        int id;
        uint8_t type;
        bool ok;
@@ -621,13 +671,16 @@ static void tldap_msg_received(struct tevent_req *subreq)
        TALLOC_FREE(subreq);
        ld->read_req = NULL;
        if (received == -1) {
-               ld->server_down = true;
                status = TLDAP_SERVER_DOWN;
                goto fail;
        }
 
        data = asn1_init(talloc_tos(), ASN1_MAX_TREE_DEPTH);
        if (data == NULL) {
+               /*
+                * We have to disconnect all, we can't tell which of
+                * the requests this reply is for.
+                */
                status = TLDAP_NO_MEMORY;
                goto fail;
        }
@@ -689,12 +742,7 @@ static void tldap_msg_received(struct tevent_req *subreq)
        return;
 
  fail:
-       while (talloc_array_length(ld->pending) > 0) {
-               req = ld->pending[0];
-               state = tevent_req_data(req, struct tldap_msg_state);
-               tevent_req_defer_callback(req, state->ev);
-               tevent_req_ldap_error(req, status);
-       }
+       tldap_context_disconnect(ld, status);
 }
 
 static TLDAPRC tldap_msg_recv(struct tevent_req *req, TALLOC_CTX *mem_ctx,