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* [PATCH] xen-block: stop leaking memory in xen_block_drive_create()
@ 2019-02-19 16:34 Paul Durrant
  0 siblings, 0 replies; 7+ messages in thread
From: Paul Durrant @ 2019-02-19 16:34 UTC (permalink / raw)
  To: qeme-devel, qemu-block, xen-devel
  Cc: Kevin Wolf, Peter Maydell, Stefano Stabellini, Max Reitz,
	Paul Durrant, Anthony Perard

The locally allocated QDict-s need to be freed. ('file_layer' will be
freed implicitly since it is added as an object to 'driver_layer').

Spotted by Coverity: CID 1398649

While in the neighbourhood free 'driver' and 'filename' as soon as they are
added to the QDicts. Freeing after the 'done' label doesn't make that much
sense as, if the error path jumps to that label, the values would be NULL
anyway.

This patch also makes that more obvious by taking the error path if
'params' is NULL and then asserting that both driver and filename are
non-NULL in the normal path.

Reported-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
---
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Anthony Perard <anthony.perard@citrix.com>
Cc: Kevin Wolf <kwolf@redhat.com>
Cc: Max Reitz <mreitz@redhat.com>
---
 hw/block/xen-block.c | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/hw/block/xen-block.c b/hw/block/xen-block.c
index 37a456c207..70fc2455e8 100644
--- a/hw/block/xen-block.c
+++ b/hw/block/xen-block.c
@@ -743,12 +743,12 @@ static XenBlockDrive *xen_block_drive_create(const char *id,
         }
 
         g_strfreev(v);
-    }
-
-    if (!filename) {
-        error_setg(errp, "no filename");
+    } else {
+        error_setg(errp, "no params");
         goto done;
     }
+
+    assert(filename);
     assert(driver);
 
     drive = g_new0(XenBlockDrive, 1);
@@ -758,6 +758,7 @@ static XenBlockDrive *xen_block_drive_create(const char *id,
 
     qdict_put_str(file_layer, "driver", "file");
     qdict_put_str(file_layer, "filename", filename);
+    g_free(filename);
 
     if (mode && *mode != 'w') {
         qdict_put_bool(file_layer, "read-only", true);
@@ -793,16 +794,17 @@ static XenBlockDrive *xen_block_drive_create(const char *id,
     driver_layer = qdict_new();
 
     qdict_put_str(driver_layer, "driver", driver);
+    g_free(driver);
+
     qdict_put_obj(driver_layer, "file", QOBJECT(file_layer));
 
     g_assert(!drive->node_name);
     drive->node_name = xen_block_blockdev_add(drive->id, driver_layer,
                                               &local_err);
 
-done:
-    g_free(driver);
-    g_free(filename);
+    qobject_unref(driver_layer);
 
+done:
     if (local_err) {
         error_propagate(errp, local_err);
         xen_block_drive_destroy(drive, NULL);
-- 
2.20.1.2.gb21ebb6


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^ permalink raw reply related	[flat|nested] 7+ messages in thread

end of thread, other threads:[~2019-02-25 16:47 UTC | newest]

Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
     [not found] <20190219163440.15702-1-paul.durrant@citrix.com>
2019-02-19 16:36 ` [Qemu-devel] [PATCH] xen-block: stop leaking memory in xen_block_drive_create() Paul Durrant
2019-02-25 16:46   ` Anthony PERARD
2019-02-25 16:46     ` Anthony PERARD
2019-02-19 16:36 ` Paul Durrant
2019-02-19 16:37 ` [Qemu-devel] " Peter Maydell
2019-02-19 16:37 ` Peter Maydell
2019-02-19 16:34 Paul Durrant

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