[libvirt] [PATCH v2 1/3] qemu: Be more selective when determining cdrom for taint messaging
https://bugzilla.redhat.com/show_bug.cgi?id=1471225
Commit id '99a2d6af2' was a bit too aggressive with determining whether
the provided path was a "physical" cd-rom in order to generate a taint
message due to the possibility of some guest and host trying to control
the tray. For cd-rom guest devices backed to some VIR_STORAGE_TYPE_FILE
storage, this wouldn't be a problem and as such it shouldn't be a problem
for guest devices using some sort of block device on the host such as
iSCSI, LVM, or a Disk pool would present.
So before issuing a taint message, let's check if the provided path of
the VIR_STORAGE_TYPE_BLOCK backed device is a "known" physical cdrom name
by comparing the beginning of the path w/ "/dev/cdrom" and "/dev/sr".
Also since it's possible the provided path could resolve to some /dev/srN
device, let's get that path as well and perform the same check.
Signed-off-by: John Ferlan <jferlan(a)redhat.com>
---
src/qemu/qemu_domain.c | 31 ++++++++++++++++++++++++++++++-
1 file changed, 30 insertions(+), 1 deletion(-)
diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index 7203189..1b0c778 100644
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
@@ -4722,6 +4722,35 @@ qemuDomainDefFormatLive(virQEMUDriverPtr driver,
}
+/* qemuDomainFilePathIsHostCDROM
+ * @path: Supplied path.
+ *
+ * Determine if the path is a host CD-ROM path. Typically this is
+ * either /dev/cdrom[n] or /dev/srN, so those are easy checks, but
+ * it's also possible that @path resolves to /dev/srN, so check for
+ * those conditions on @path in order to emit the tainted message.
+ *
+ * Returns true if the path is a CDROM, false otherwise or on error.
+ */
+static bool
+qemuDomainFilePathIsHostCDROM(const char *path)
+{
+ bool ret = false;
+ char *linkpath = NULL;
+
+ if (virFileResolveLink(path, &linkpath) < 0)
+ goto cleanup;
+
+ if (STRPREFIX(path, "/dev/cdrom") || STRPREFIX(path, "/dev/sr")
||
+ STRPREFIX(linkpath, "/dev/sr"))
+ ret = true;
+
+ cleanup:
+ VIR_FREE(linkpath);
+ return ret;
+}
+
+
void qemuDomainObjTaint(virQEMUDriverPtr driver,
virDomainObjPtr obj,
virDomainTaintFlags taint,
@@ -4840,7 +4869,7 @@ void qemuDomainObjCheckDiskTaint(virQEMUDriverPtr driver,
if (disk->device == VIR_DOMAIN_DISK_DEVICE_CDROM &&
virStorageSourceGetActualType(disk->src) == VIR_STORAGE_TYPE_BLOCK &&
- disk->src->path)
+ disk->src->path &&
qemuDomainFilePathIsHostCDROM(disk->src->path))
qemuDomainObjTaint(driver, obj, VIR_DOMAIN_TAINT_CDROM_PASSTHROUGH,
logCtxt);
--
2.9.5