[pve-devel] [PATCH qemu] zeroinit: fix regression with filename parsing

[Fiona Ebner]

As reported in the community forum [0], cloning or importing images
to RBD storages (without the krbd setting) was broken. This is a
result of no filename parsing happening anymore in bdrv_open_child()
after commit b242e7f ("backport fix for CVE-2024-4467"), which the
zeroinit relied on for passing along the RBD filename+key-value pairs.

There is a dedicated function for opening the file child which still
does filename parsing. Use that for opening the file child. Role and
flags should still be the same as with the manual bdrv_open_child(),
because the zeroinit driver is a filter, and the assignment bs->file
is also done by bdrv_open_file_child().

Fixes: b242e7f ("backport fix for CVE-2024-4467")
Signed-off-by: Fiona Ebner <f.ebner at proxmox.com>
---
 ...add-the-zeroinit-block-driver-filter.patch | 24 +++++++------------
 1 file changed, 9 insertions(+), 15 deletions(-)

diff --git a/debian/patches/pve/0019-PVE-block-add-the-zeroinit-block-driver-filter.patch b/debian/patches/pve/0019-PVE-block-add-the-zeroinit-block-driver-filter.patch
index 34a7efe..7464ca5 100644
--- a/debian/patches/pve/0019-PVE-block-add-the-zeroinit-block-driver-filter.patch
+++ b/debian/patches/pve/0019-PVE-block-add-the-zeroinit-block-driver-filter.patch
@@ -5,12 +5,13 @@ Subject: [PATCH] PVE: block: add the zeroinit block driver filter
 
 Signed-off-by: Thomas Lamprecht <t.lamprecht at proxmox.com>
 [FE: adapt to changed function signatures
-     adhere to block graph lock requirements]
+     adhere to block graph lock requirements
+     use dedicated function to open file child]
 Signed-off-by: Fiona Ebner <f.ebner at proxmox.com>
 ---
  block/meson.build |   1 +
- block/zeroinit.c  | 214 ++++++++++++++++++++++++++++++++++++++++++++++
- 2 files changed, 215 insertions(+)
+ block/zeroinit.c  | 207 ++++++++++++++++++++++++++++++++++++++++++++++
+ 2 files changed, 208 insertions(+)
  create mode 100644 block/zeroinit.c
 
 diff --git a/block/meson.build b/block/meson.build
@@ -27,10 +28,10 @@ index e1f03fd773..b530e117b5 100644
  system_ss.add(when: 'CONFIG_TCG', if_true: files('blkreplay.c'))
 diff --git a/block/zeroinit.c b/block/zeroinit.c
 new file mode 100644
-index 0000000000..696558d8d6
+index 0000000000..7998c9332d
 --- /dev/null
 +++ b/block/zeroinit.c
-@@ -0,0 +1,214 @@
+@@ -0,0 +1,207 @@
 +/*
 + * Filter to fake a zero-initialized block device.
 + *
@@ -96,7 +97,6 @@ index 0000000000..696558d8d6
 +                          Error **errp)
 +{
 +    BDRVZeroinitState *s = bs->opaque;
-+    BdrvChild *file = NULL;
 +    QemuOpts *opts;
 +    Error *local_err = NULL;
 +    int ret;
@@ -112,15 +112,9 @@ index 0000000000..696558d8d6
 +    }
 +
 +    /* Open the raw file */
-+    file = bdrv_open_child(qemu_opt_get(opts, "x-next"), options, "next", bs,
-+                           &child_of_bds,
-+                           BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY, false,
-+                           &local_err);
-+    bdrv_graph_wrlock();
-+    bs->file = file;
-+    bdrv_graph_wrunlock();
-+    if (local_err) {
-+        ret = -EINVAL;
++    ret = bdrv_open_file_child(qemu_opt_get(opts, "x-next"), options, "next",
++                               bs, &local_err);
++    if (ret < 0) {
 +        error_propagate(errp, local_err);
 +        goto fail;
 +    }
-- 
2.39.2