Fixing serious memory allocation bug in sbus_message_handler.

dbus_message_append_args() adds a reference to memory that is not
copied to the outgoing message until dbus_connection_send() is
called. Since we compile our reply messages in functions and then
return the reply, we need a mechanism for deleting allocated
memory after invoking dbus_connection_send. I have changed the
arguments to sbus_msg_handler_fn so that it takes a talloc ctx
containing the sbus_message_handler_ctx and a pointer to a reply
object. We can now allocate memory as a child of the reply context
and free it after calling dbus_connection_send.

2 files changed, 51 insertions, 66 deletions

diff --git a/server/providers/data_provider.c b/server/providers/data_provider.c
index aa66c8e5..c1dc2801 100644
--- a/server/providers/data_provider.c
+++ b/server/providers/data_provider.c
@@ -76,9 +76,9 @@ struct dp_frontend {
 static int dp_backend_destructor(void *ctx);
 static int dp_frontend_destructor(void *ctx);
 
-static int service_identity(DBusMessage *message, void *data, DBusMessage **r);
-static int service_pong(DBusMessage *message, void *data, DBusMessage **r);
-static int service_reload(DBusMessage *message, void *data, DBusMessage **r);
+static int service_identity(DBusMessage *message, struct sbus_message_ctx *reply);
+static int service_pong(DBusMessage *message, struct sbus_message_ctx *reply);
+static int service_reload(DBusMessage *message, struct sbus_message_ctx *reply);
 
 struct sbus_method mon_sbus_methods[] = {
     { SERVICE_METHOD_IDENTITY, service_identity },
@@ -87,7 +87,7 @@ struct sbus_method mon_sbus_methods[] = {
     { NULL, NULL }
 };
 
-static int dp_get_account_info(DBusMessage *message, void *data, DBusMessage **r);
+static int dp_get_account_info(DBusMessage *message, struct sbus_message_ctx *reply);
 
 struct sbus_method dp_sbus_methods[] = {
     { DP_SRV_METHOD_GETACCTINFO, dp_get_account_info },
@@ -108,17 +108,16 @@ struct dp_be_request {
     struct dp_backend *be;
 };
 
-static int service_identity(DBusMessage *message, void *data, DBusMessage **r)
+static int service_identity(DBusMessage *message, struct sbus_message_ctx *reply)
 {
     dbus_uint16_t version = DATA_PROVIDER_VERSION;
     const char *name = DATA_PROVIDER_SERVICE_NAME;
-    DBusMessage *reply;
     dbus_bool_t ret;
 
     DEBUG(4, ("Sending identity data [%s,%d]\n", name, version));
 
-    reply = dbus_message_new_method_return(message);
-    ret = dbus_message_append_args(reply,
+    reply->reply_message = dbus_message_new_method_return(message);
+    ret = dbus_message_append_args(reply->reply_message,
                                    DBUS_TYPE_STRING, &name,
                                    DBUS_TYPE_UINT16, &version,
                                    DBUS_TYPE_INVALID);
@@ -126,33 +125,30 @@ static int service_identity(DBusMessage *message, void *data, DBusMessage **r)
         return EIO;
     }
 
-    *r = reply;
     return EOK;
 }
 
-static int service_pong(DBusMessage *message, void *data, DBusMessage **r)
+static int service_pong(DBusMessage *message, struct sbus_message_ctx *reply)
 {
-    DBusMessage *reply;
     dbus_bool_t ret;
 
-    reply = dbus_message_new_method_return(message);
-    ret = dbus_message_append_args(reply, DBUS_TYPE_INVALID);
+    reply->reply_message = dbus_message_new_method_return(message);
+    ret = dbus_message_append_args(reply->reply_message, DBUS_TYPE_INVALID);
     if (!ret) {
         return EIO;
     }
 
-    *r = reply;
     return EOK;
 }
 
-static int service_reload(DBusMessage *message, void *data, DBusMessage **r) {
+static int service_reload(DBusMessage *message, struct sbus_message_ctx *reply) {
     /* Monitor calls this function when we need to reload
      * our configuration information. Perform whatever steps
      * are needed to update the configuration objects.
      */
 
     /* Send an empty reply to acknowledge receipt */
-    return service_pong(message, data, r);
+    return service_pong(message, reply);
 }
 
 static int dp_monitor_init(struct dp_ctx *dpctx)
@@ -538,14 +534,13 @@ static int dp_send_acct_req(struct dp_be_request *bereq,
     return EOK;
 }
 
-static int dp_get_account_info(DBusMessage *message, void *data, DBusMessage **r)
+static int dp_get_account_info(DBusMessage *message, struct sbus_message_ctx *reply)
 {
     struct sbus_message_handler_ctx *smh_ctx;
     struct dp_client *dpcli;
     struct dp_be_request *bereq;
     struct dp_request *dpreq = NULL;
     struct dp_backend *dpbe;
-    DBusMessage *reply;
     DBusError dbus_error;
     dbus_bool_t dbret;
     void *user_data;
@@ -554,9 +549,11 @@ static int dp_get_account_info(DBusMessage *message, void *data, DBusMessage **r
     const char *errmsg = NULL;
     int dpret = 0, ret = 0;
 
-    if (!data) return EINVAL;
-    smh_ctx = talloc_get_type(data, struct sbus_message_handler_ctx);
+    if (!reply) return EINVAL;
+
+    smh_ctx = reply->mh_ctx;
     if (!smh_ctx) return EINVAL;
+
     user_data = sbus_conn_get_private_data(smh_ctx->conn_ctx);
     if (!user_data) return EINVAL;
     dpcli = talloc_get_type(user_data, struct dp_client);
@@ -578,7 +575,7 @@ static int dp_get_account_info(DBusMessage *message, void *data, DBusMessage **r
     DEBUG(4, ("Got request for [%s][%u][%s][%s]\n",
               domain, type, attrs, filter));
 
-    reply = dbus_message_new_method_return(message);
+    reply->reply_message = dbus_message_new_method_return(message);
 
     /* search for domain */
     if (!domain) {
@@ -606,7 +603,7 @@ static int dp_get_account_info(DBusMessage *message, void *data, DBusMessage **r
             goto respond;
         }
 
-        dpreq->reply = reply;
+        dpreq->reply = reply->reply_message;
         dpreq->src_cli = dpcli;
         dpreq->pending_replies = 0;
 
@@ -662,7 +659,7 @@ static int dp_get_account_info(DBusMessage *message, void *data, DBusMessage **r
             goto respond;
         }
 
-        dpreq->reply = reply;
+        dpreq->reply = reply->reply_message;
         dpreq->src_cli = dpcli;
         dpreq->pending_replies = 1;
 
@@ -698,14 +695,13 @@ static int dp_get_account_info(DBusMessage *message, void *data, DBusMessage **r
     return EOK;
 
 respond:
-    dbret = dbus_message_append_args(reply,
+    dbret = dbus_message_append_args(reply->reply_message,
                                      DBUS_TYPE_UINT16, &dpret,
                                      DBUS_TYPE_UINT32, &ret,
                                      DBUS_TYPE_STRING, &errmsg,
                                      DBUS_TYPE_INVALID);
     if (!dbret) return EIO;
 
-    *r = reply;
     return EOK;
 }
 
diff --git a/server/providers/data_provider_be.c b/server/providers/data_provider_be.c
index 7b491ce7..c12e2b2f 100644
--- a/server/providers/data_provider_be.c
+++ b/server/providers/data_provider_be.c
@@ -44,8 +44,8 @@
 
 typedef int (*be_init_fn_t)(TALLOC_CTX *, struct be_mod_ops **, void **);
 
-static int service_identity(DBusMessage *message, void *data, DBusMessage **r);
-static int service_pong(DBusMessage *message, void *data, DBusMessage **r);
+static int service_identity(DBusMessage *message, struct sbus_message_ctx *reply);
+static int service_pong(DBusMessage *message, struct sbus_message_ctx *reply);
 
 struct sbus_method mon_sbus_methods[] = {
     { SERVICE_METHOD_IDENTITY, service_identity },
@@ -53,9 +53,9 @@ struct sbus_method mon_sbus_methods[] = {
     { NULL, NULL }
 };
 
-static int be_identity(DBusMessage *message, void *data, DBusMessage **r);
-static int be_check_online(DBusMessage *message, void *data, DBusMessage **r);
-static int be_get_account_info(DBusMessage *message, void *data, DBusMessage **r);
+static int be_identity(DBusMessage *message, struct sbus_message_ctx *reply);
+static int be_check_online(DBusMessage *message, struct sbus_message_ctx *reply);
+static int be_get_account_info(DBusMessage *message, struct sbus_message_ctx *reply);
 
 struct sbus_method be_methods[] = {
     { DP_CLI_METHOD_IDENTITY, be_identity },
@@ -64,17 +64,16 @@ struct sbus_method be_methods[] = {
     { NULL, NULL }
 };
 
-static int service_identity(DBusMessage *message, void *data, DBusMessage **r)
+static int service_identity(DBusMessage *message, struct sbus_message_ctx *reply)
 {
     dbus_uint16_t version = DATA_PROVIDER_VERSION;
     struct sbus_message_handler_ctx *smh_ctx;
     struct be_ctx *ctx;
-    DBusMessage *reply;
     dbus_bool_t ret;
     void *user_data;
 
-    if (!data) return EINVAL;
-    smh_ctx = talloc_get_type(data, struct sbus_message_handler_ctx);
+    if (!reply) return EINVAL;
+    smh_ctx = reply->mh_ctx;
     if (!smh_ctx) return EINVAL;
     user_data = sbus_conn_get_private_data(smh_ctx->conn_ctx);
     if (!user_data) return EINVAL;
@@ -83,8 +82,8 @@ static int service_identity(DBusMessage *message, void *data, DBusMessage **r)
 
     DEBUG(4,("Sending ID reply: (%s,%d)\n", ctx->identity, version));
 
-    reply = dbus_message_new_method_return(message);
-    ret = dbus_message_append_args(reply,
+    reply->reply_message = dbus_message_new_method_return(message);
+    ret = dbus_message_append_args(reply->reply_message,
                                    DBUS_TYPE_STRING, &ctx->identity,
                                    DBUS_TYPE_UINT16, &version,
                                    DBUS_TYPE_INVALID);
@@ -92,37 +91,33 @@ static int service_identity(DBusMessage *message, void *data, DBusMessage **r)
         return EIO;
     }
 
-    *r = reply;
     return EOK;
 }
 
-static int service_pong(DBusMessage *message, void *data, DBusMessage **r)
+static int service_pong(DBusMessage *message, struct sbus_message_ctx *reply)
 {
-    DBusMessage *reply;
     dbus_bool_t ret;
 
-    reply = dbus_message_new_method_return(message);
-    ret = dbus_message_append_args(reply, DBUS_TYPE_INVALID);
+    reply->reply_message = dbus_message_new_method_return(message);
+    ret = dbus_message_append_args(reply->reply_message, DBUS_TYPE_INVALID);
     if (!ret) {
         return EIO;
     }
 
-    *r = reply;
     return EOK;
 }
 
-static int be_identity(DBusMessage *message, void *data, DBusMessage **r)
+static int be_identity(DBusMessage *message, struct sbus_message_ctx *reply)
 {
     dbus_uint16_t version = DATA_PROVIDER_VERSION;
     dbus_uint16_t clitype = DP_CLI_BACKEND;
     struct sbus_message_handler_ctx *smh_ctx;
     struct be_ctx *ctx;
-    DBusMessage *reply;
     dbus_bool_t ret;
     void *user_data;
 
-    if (!data) return EINVAL;
-    smh_ctx = talloc_get_type(data, struct sbus_message_handler_ctx);
+    if (!reply) return EINVAL;
+    smh_ctx = reply->mh_ctx;
     if (!smh_ctx) return EINVAL;
     user_data = sbus_conn_get_private_data(smh_ctx->conn_ctx);
     if (!user_data) return EINVAL;
@@ -132,8 +127,8 @@ static int be_identity(DBusMessage *message, void *data, DBusMessage **r)
     DEBUG(4,("Sending ID reply: (%d,%d,%s,%s)\n",
              clitype, version, ctx->name, ctx->domain));
 
-    reply = dbus_message_new_method_return(message);
-    ret = dbus_message_append_args(reply,
+    reply->reply_message = dbus_message_new_method_return(message);
+    ret = dbus_message_append_args(reply->reply_message,
                                    DBUS_TYPE_UINT16, &clitype,
                                    DBUS_TYPE_UINT16, &version,
                                    DBUS_TYPE_STRING, &ctx->name,
@@ -143,7 +138,6 @@ static int be_identity(DBusMessage *message, void *data, DBusMessage **r)
         return EIO;
     }
 
-    *r = reply;
     return EOK;
 }
 
@@ -237,13 +231,12 @@ static void online_chk_callback(struct be_req *req, int status,
 }
 
 
-static int be_check_online(DBusMessage *message, void *data, DBusMessage **r)
+static int be_check_online(DBusMessage *message, struct sbus_message_ctx *reply)
 {
     struct sbus_message_handler_ctx *smh_ctx;
     struct be_online_req *req;
     struct be_req *be_req;
     struct be_ctx *ctx;
-    DBusMessage *reply;
     dbus_bool_t dbret;
     void *user_data;
     int ret;
@@ -252,15 +245,15 @@ static int be_check_online(DBusMessage *message, void *data, DBusMessage **r)
     dbus_uint32_t err_min;
     const char *err_msg;
 
-    if (!data) return EINVAL;
-    smh_ctx = talloc_get_type(data, struct sbus_message_handler_ctx);
+    if (!reply) return EINVAL;
+    smh_ctx = reply->mh_ctx;
     if (!smh_ctx) return EINVAL;
     user_data = sbus_conn_get_private_data(smh_ctx->conn_ctx);
     if (!user_data) return EINVAL;
     ctx = talloc_get_type(user_data, struct be_ctx);
     if (!ctx) return EINVAL;
 
-    reply = dbus_message_new_method_return(message);
+    reply->reply_message = dbus_message_new_method_return(message);
 
     /* process request */
     be_req = talloc(ctx, struct be_req);
@@ -273,7 +266,7 @@ static int be_check_online(DBusMessage *message, void *data, DBusMessage **r)
     }
     be_req->be_ctx = ctx;
     be_req->fn = online_chk_callback;
-    be_req->pvt = reply;
+    be_req->pvt = reply->reply_message;
 
     req = talloc(be_req, struct be_online_req);
     if (!req) {
@@ -303,7 +296,7 @@ done:
         talloc_free(be_req);
     }
 
-    dbret = dbus_message_append_args(reply,
+    dbret = dbus_message_append_args(reply->reply_message,
                                      DBUS_TYPE_UINT16, &online,
                                      DBUS_TYPE_UINT16, &err_maj,
                                      DBUS_TYPE_UINT32, &err_min,
@@ -311,7 +304,6 @@ done:
                                      DBUS_TYPE_INVALID);
     if (!dbret) return EIO;
 
-    *r = reply;
     return EOK;
 }
 
@@ -355,13 +347,12 @@ static void acctinfo_callback(struct be_req *req, int status,
     talloc_free(req);
 }
 
-static int be_get_account_info(DBusMessage *message, void *data, DBusMessage **r)
+static int be_get_account_info(DBusMessage *message, struct sbus_message_ctx *reply)
 {
     struct sbus_message_handler_ctx *smh_ctx;
     struct be_acct_req *req;
     struct be_req *be_req;
     struct be_ctx *ctx;
-    DBusMessage *reply;
     DBusError dbus_error;
     dbus_bool_t dbret;
     void *user_data;
@@ -375,10 +366,9 @@ static int be_get_account_info(DBusMessage *message, void *data, DBusMessage **r
     const char *err_msg;
 
     be_req = NULL;
-    *r = NULL;
 
-    if (!data) return EINVAL;
-    smh_ctx = talloc_get_type(data, struct sbus_message_handler_ctx);
+    if (!reply) return EINVAL;
+    smh_ctx = reply->mh_ctx;
     if (!smh_ctx) return EINVAL;
     user_data = sbus_conn_get_private_data(smh_ctx->conn_ctx);
     if (!user_data) return EINVAL;
@@ -399,7 +389,7 @@ static int be_get_account_info(DBusMessage *message, void *data, DBusMessage **r
 
     DEBUG(4, ("Got request for [%u][%s][%s]\n", type, attrs, filter));
 
-    reply = dbus_message_new_method_return(message);
+    reply->reply_message = dbus_message_new_method_return(message);
 
     if (attrs) {
         if (strcmp(attrs, "core") == 0) attr_type = BE_ATTR_CORE;
@@ -448,7 +438,7 @@ static int be_get_account_info(DBusMessage *message, void *data, DBusMessage **r
     }
     be_req->be_ctx = ctx;
     be_req->fn = acctinfo_callback;
-    be_req->pvt = reply;
+    be_req->pvt = reply->reply_message;
 
     req = talloc(be_req, struct be_acct_req);
     if (!req) {
@@ -479,7 +469,7 @@ done:
         talloc_free(be_req);
     }
 
-    dbret = dbus_message_append_args(reply,
+    dbret = dbus_message_append_args(reply->reply_message,
                                      DBUS_TYPE_UINT16, &err_maj,
                                      DBUS_TYPE_UINT32, &err_min,
                                      DBUS_TYPE_STRING, &err_msg,
@@ -489,7 +479,6 @@ done:
     DEBUG(4, ("Request processed. Returned %d,%d,%s\n",
               err_maj, err_min, err_msg));
 
-    *r = reply;
     return EOK;
 }