netlogon_creds_cli: Add netlogon_creds_cli_lck

This adds an external locking scheme to protect our
netlogon_creds_CredentialState. This is needed because the routines
exposed by netlogon_creds_cli.h need a more flexible locking to
set up our credentials in a properly protected way.

Signed-off-by: Volker Lendecke <vl@samba.org>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>

2 files changed, 163 insertions, 0 deletions

diff --git a/libcli/auth/netlogon_creds_cli.c b/libcli/auth/netlogon_creds_cli.c
index 3209f6cf871..06d7260c8b6 100644
--- a/libcli/auth/netlogon_creds_cli.c
+++ b/libcli/auth/netlogon_creds_cli.c
@@ -68,6 +68,7 @@ struct netlogon_creds_cli_context {
 		struct db_context *ctx;
 		struct g_lock_ctx *g_ctx;
 		struct netlogon_creds_cli_locked_state *locked_state;
+		enum netlogon_creds_cli_lck_type lock;
 	} db;
 };
 
@@ -909,6 +910,148 @@ NTSTATUS netlogon_creds_cli_lock(struct netlogon_creds_cli_context *context,
 	return status;
 }
 
+struct netlogon_creds_cli_lck {
+	struct netlogon_creds_cli_context *context;
+};
+
+struct netlogon_creds_cli_lck_state {
+	struct netlogon_creds_cli_lck *lck;
+	enum netlogon_creds_cli_lck_type type;
+};
+
+static void netlogon_creds_cli_lck_locked(struct tevent_req *subreq);
+static int netlogon_creds_cli_lck_destructor(
+	struct netlogon_creds_cli_lck *lck);
+
+struct tevent_req *netlogon_creds_cli_lck_send(
+	TALLOC_CTX *mem_ctx, struct tevent_context *ev,
+	struct netlogon_creds_cli_context *context,
+	enum netlogon_creds_cli_lck_type type)
+{
+	struct tevent_req *req, *subreq;
+	struct netlogon_creds_cli_lck_state *state;
+	enum g_lock_type gtype;
+
+	req = tevent_req_create(mem_ctx, &state,
+				struct netlogon_creds_cli_lck_state);
+	if (req == NULL) {
+		return NULL;
+	}
+
+	if (context->db.lock != NETLOGON_CREDS_CLI_LCK_NONE) {
+		DBG_DEBUG("context already locked\n");
+		tevent_req_nterror(req, NT_STATUS_INVALID_LOCK_SEQUENCE);
+		return tevent_req_post(req, ev);
+	}
+
+	switch (type) {
+	    case NETLOGON_CREDS_CLI_LCK_SHARED:
+		    gtype = G_LOCK_READ;
+		    break;
+	    case NETLOGON_CREDS_CLI_LCK_EXCLUSIVE:
+		    gtype = G_LOCK_WRITE;
+		    break;
+	    default:
+		    tevent_req_nterror(req, NT_STATUS_INVALID_PARAMETER);
+		    return tevent_req_post(req, ev);
+	}
+
+	state->lck = talloc(state, struct netlogon_creds_cli_lck);
+	if (tevent_req_nomem(state->lck, req)) {
+		return tevent_req_post(req, ev);
+	}
+	state->lck->context = context;
+	state->type = type;
+
+	subreq = g_lock_lock_send(state, ev,
+				  context->db.g_ctx,
+				  context->db.key_name,
+				  gtype);
+	if (tevent_req_nomem(subreq, req)) {
+		return tevent_req_post(req, ev);
+	}
+	tevent_req_set_callback(subreq, netlogon_creds_cli_lck_locked, req);
+
+	return req;
+}
+
+static void netlogon_creds_cli_lck_locked(struct tevent_req *subreq)
+{
+	struct tevent_req *req = tevent_req_callback_data(
+		subreq, struct tevent_req);
+	struct netlogon_creds_cli_lck_state *state = tevent_req_data(
+		req, struct netlogon_creds_cli_lck_state);
+	NTSTATUS status;
+
+	status = g_lock_lock_recv(subreq);
+	TALLOC_FREE(subreq);
+	if (tevent_req_nterror(req, status)) {
+		return;
+	}
+
+	state->lck->context->db.lock = state->type;
+	talloc_set_destructor(state->lck, netlogon_creds_cli_lck_destructor);
+
+	tevent_req_done(req);
+}
+
+static int netlogon_creds_cli_lck_destructor(
+	struct netlogon_creds_cli_lck *lck)
+{
+	struct netlogon_creds_cli_context *ctx = lck->context;
+	NTSTATUS status;
+
+	status = g_lock_unlock(ctx->db.g_ctx, ctx->db.key_name);
+	if (!NT_STATUS_IS_OK(status)) {
+		DBG_WARNING("g_lock_unlock failed: %s\n", nt_errstr(status));
+		smb_panic("g_lock_unlock failed");
+	}
+	ctx->db.lock = NETLOGON_CREDS_CLI_LCK_NONE;
+	return 0;
+}
+
+NTSTATUS netlogon_creds_cli_lck_recv(
+	struct tevent_req *req, TALLOC_CTX *mem_ctx,
+	struct netlogon_creds_cli_lck **lck)
+{
+	struct netlogon_creds_cli_lck_state *state = tevent_req_data(
+		req, struct netlogon_creds_cli_lck_state);
+	NTSTATUS status;
+
+	if (tevent_req_is_nterror(req, &status)) {
+		return status;
+	}
+	*lck = talloc_move(mem_ctx, &state->lck);
+	return NT_STATUS_OK;
+}
+
+NTSTATUS netlogon_creds_cli_lck(
+	struct netlogon_creds_cli_context *context,
+	enum netlogon_creds_cli_lck_type type,
+	TALLOC_CTX *mem_ctx, struct netlogon_creds_cli_lck **lck)
+{
+	TALLOC_CTX *frame = talloc_stackframe();
+	struct tevent_context *ev;
+	struct tevent_req *req;
+	NTSTATUS status = NT_STATUS_NO_MEMORY;
+
+	ev = samba_tevent_context_init(frame);
+	if (ev == NULL) {
+		goto fail;
+	}
+	req = netlogon_creds_cli_lck_send(frame, ev, context, type);
+	if (req == NULL) {
+		goto fail;
+	}
+	if (!tevent_req_poll_ntstatus(req, ev, &status)) {
+		goto fail;
+	}
+	status = netlogon_creds_cli_lck_recv(req, mem_ctx, lck);
+ fail:
+	TALLOC_FREE(frame);
+	return status;
+}
+
 struct netlogon_creds_cli_auth_state {
 	struct tevent_context *ev;
 	struct netlogon_creds_cli_context *context;
diff --git a/libcli/auth/netlogon_creds_cli.h b/libcli/auth/netlogon_creds_cli.h
index 7664387ab95..b3e30eb67bf 100644
--- a/libcli/auth/netlogon_creds_cli.h
+++ b/libcli/auth/netlogon_creds_cli.h
@@ -76,6 +76,26 @@ NTSTATUS netlogon_creds_cli_lock(struct netlogon_creds_cli_context *context,
 			TALLOC_CTX *mem_ctx,
 			struct netlogon_creds_CredentialState **creds);
 
+struct netlogon_creds_cli_lck;
+
+enum netlogon_creds_cli_lck_type {
+	NETLOGON_CREDS_CLI_LCK_NONE,
+	NETLOGON_CREDS_CLI_LCK_SHARED,
+	NETLOGON_CREDS_CLI_LCK_EXCLUSIVE,
+};
+
+struct tevent_req *netlogon_creds_cli_lck_send(
+	TALLOC_CTX *mem_ctx, struct tevent_context *ev,
+	struct netlogon_creds_cli_context *context,
+	enum netlogon_creds_cli_lck_type type);
+NTSTATUS netlogon_creds_cli_lck_recv(
+	struct tevent_req *req, TALLOC_CTX *mem_ctx,
+	struct netlogon_creds_cli_lck **lck);
+NTSTATUS netlogon_creds_cli_lck(
+	struct netlogon_creds_cli_context *context,
+	enum netlogon_creds_cli_lck_type type,
+	TALLOC_CTX *mem_ctx, struct netlogon_creds_cli_lck **lck);
+
 struct tevent_req *netlogon_creds_cli_auth_send(TALLOC_CTX *mem_ctx,
 				struct tevent_context *ev,
 				struct netlogon_creds_cli_context *context,