libvirt/SOURCES/libvirt-node_device-Don-t-leak-error-message-buffer-from-virMdevctlListDefined-Active.patch

From f158b6573ac39bdd1ba36c3900e65afffe57f3ca Mon Sep 17 00:00:00 2001
Message-ID: <f158b6573ac39bdd1ba36c3900e65afffe57f3ca.1689974710.git.jdenemar@redhat.com>
From: Peter Krempa <pkrempa@redhat.com>
Date: Wed, 19 Jul 2023 15:22:22 +0200
Subject: [PATCH] node_device: Don't leak error message buffer from
 virMdevctlListDefined|Active

nodeDeviceUpdateMediatedDevices invokes virMdevctlListDefined and
virMdevctlListActive both of which were passed the same 'errmsg' buffer.

Since virCommandSetErrorBuffer() always allocates the error buffer one
of them was leaked.

Fix it by populating the 'errmsg' buffer only on failure of
virMdevctlListActive|Defined which invoke the command.

Add a comment to nodeDeviceGetMdevctlListCommand reminding how
virCommandSetErrorBuffer() works.

Fixes: 44a0f2f0c8f
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Boris Fiuczynski <fiuczy@linux.ibm.com>

Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=2143158

(cherry picked from commit 7ca777cc09242cb3a30b12d5e0e396c6aaf1a5e7)
Signed-off-by: Jonathon Jongsma <jjongsma@redhat.com>
---
 src/node_device/node_device_driver.c | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/src/node_device/node_device_driver.c b/src/node_device/node_device_driver.c
index 5dc45ddbb4..2ef9197adc 100644
--- a/src/node_device/node_device_driver.c
+++ b/src/node_device/node_device_driver.c
@@ -1044,6 +1044,15 @@ virMdevctlSetAutostart(virNodeDeviceDef *def, bool autostart, char **errmsg)
 }
 
 
+/**
+ * nodeDeviceGetMdevctlListCommand:
+ * @defined: list mdevctl entries with persistent config
+ * @output: filled with the output of mdevctl once invoked
+ * @errmsg: always allocated, optionally filled with error from 'mdevctl'
+ *
+ * Prepares a virCommand structure to invoke 'mdevctl' caller is responsible to
+ * free the buffers which are filled by the virCommand infrastructure.
+ */
 virCommand*
 nodeDeviceGetMdevctlListCommand(bool defined,
                                 char **output,
@@ -1624,9 +1633,11 @@ virMdevctlListDefined(virNodeDeviceDef ***devs, char **errmsg)
 {
     int status;
     g_autofree char *output = NULL;
-    g_autoptr(virCommand) cmd = nodeDeviceGetMdevctlListCommand(true, &output, errmsg);
+    g_autofree char *errbuf = NULL;
+    g_autoptr(virCommand) cmd = nodeDeviceGetMdevctlListCommand(true, &output, &errbuf);
 
     if (virCommandRun(cmd, &status) < 0 || status != 0) {
+        *errmsg = g_steal_pointer(&errbuf);
         return -1;
     }
 
@@ -1642,9 +1653,11 @@ virMdevctlListActive(virNodeDeviceDef ***devs, char **errmsg)
 {
     int status;
     g_autofree char *output = NULL;
-    g_autoptr(virCommand) cmd = nodeDeviceGetMdevctlListCommand(false, &output, errmsg);
+    g_autofree char *errbuf = NULL;
+    g_autoptr(virCommand) cmd = nodeDeviceGetMdevctlListCommand(false, &output, &errbuf);
 
     if (virCommandRun(cmd, &status) < 0 || status != 0) {
+        *errmsg = g_steal_pointer(&errbuf);
         return -1;
     }
 
-- 
2.41.0