From: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Date: Tue, 7 Mar 2023 19:38:32 +0000 (-0500)
Subject: Fix: consumerd: type confusion in lttng_consumer_send_error
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=fbd566c25787aa7134e84efcfb7d3569f27d3350;p=lttng-tools.git

Fix: consumerd: type confusion in lttng_consumer_send_error

lttng_consumer_send_error sends an lttcomm_return_code to the session
daemon. However, the size of lttcomm_sessiond_command was used.

This was probably missed since the function accepts an integer instead
of a proper enum type.

The size accepted by the function is changed to use lttcomm_return_code
and the size of a fixed-size type is used to send the error code to the
session daemon.

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Change-Id: I318e6a8d145373779d11557a70e43abca9783e5c
---

diff --git a/src/bin/lttng-sessiond/manage-consumer.cpp b/src/bin/lttng-sessiond/manage-consumer.cpp
index b7eb10800..27a368e7f 100644
--- a/src/bin/lttng-sessiond/manage-consumer.cpp
+++ b/src/bin/lttng-sessiond/manage-consumer.cpp
@@ -164,8 +164,13 @@ static void *thread_consumer_management(void *data)
 
 	DBG2("Receiving code from consumer err_sock");
 
-	/* Getting status code from kconsumerd */
-	ret = lttcomm_recv_unix_sock(sock, &code, sizeof(enum lttcomm_return_code));
+	/* Getting status code from consumerd */
+	{
+		std::int32_t comm_code = 0;
+
+		ret = lttcomm_recv_unix_sock(sock, &comm_code, sizeof(comm_code));
+		code = static_cast<decltype(code)>(comm_code);
+	}
 	if (ret <= 0) {
 		mark_thread_intialization_as_failed(notifiers);
 		goto error;
@@ -304,9 +309,14 @@ static void *thread_consumer_management(void *data)
 					goto error;
 				}
 				health_code_update();
-				/* Wait for any kconsumerd error */
-				ret = lttcomm_recv_unix_sock(
-					sock, &code, sizeof(enum lttcomm_return_code));
+				/* Wait for any consumerd error */
+				{
+					std::int32_t comm_code = 0;
+
+					ret = lttcomm_recv_unix_sock(
+						sock, &comm_code, sizeof(comm_code));
+					code = static_cast<decltype(code)>(comm_code);
+				}
 				if (ret <= 0) {
 					ERR("consumer closed the command socket");
 					goto error;
diff --git a/src/common/consumer/consumer.cpp b/src/common/consumer/consumer.cpp
index 7e7e7d384..ed844f8df 100644
--- a/src/common/consumer/consumer.cpp
+++ b/src/common/consumer/consumer.cpp
@@ -45,6 +45,7 @@
 #include <sys/mman.h>
 #include <sys/socket.h>
 #include <sys/types.h>
+#include <type_traits>
 #include <unistd.h>
 
 lttng_consumer_global_data the_consumer_data;
@@ -1255,11 +1256,17 @@ void lttng_consumer_set_command_sock_path(struct lttng_consumer_local_data *ctx,
  * Send return code to the session daemon.
  * If the socket is not defined, we return 0, it is not a fatal error
  */
-int lttng_consumer_send_error(struct lttng_consumer_local_data *ctx, int cmd)
+int lttng_consumer_send_error(struct lttng_consumer_local_data *ctx,
+			      enum lttcomm_return_code error_code)
 {
 	if (ctx->consumer_error_socket > 0) {
+		const std::int32_t comm_code = std::int32_t(error_code);
+
+		static_assert(
+			sizeof(comm_code) >= sizeof(std::underlying_type<lttcomm_return_code>),
+			"Fixed-size communication type too small to accomodate lttcomm_return_code");
 		return lttcomm_send_unix_sock(
-			ctx->consumer_error_socket, &cmd, sizeof(enum lttcomm_sessiond_command));
+			ctx->consumer_error_socket, &comm_code, sizeof(comm_code));
 	}
 
 	return 0;
diff --git a/src/common/consumer/consumer.hpp b/src/common/consumer/consumer.hpp
index c62e01453..310969172 100644
--- a/src/common/consumer/consumer.hpp
+++ b/src/common/consumer/consumer.hpp
@@ -921,7 +921,8 @@ void lttng_consumer_set_command_sock_path(struct lttng_consumer_local_data *ctx,
  * Returns the return code of sendmsg : the number of bytes transmitted or -1
  * on error.
  */
-int lttng_consumer_send_error(struct lttng_consumer_local_data *ctx, int cmd);
+int lttng_consumer_send_error(struct lttng_consumer_local_data *ctx,
+		enum lttcomm_return_code error_code);
 
 /*
  * Called from signal handler to ensure a clean exit.