Re: [libvirt] [PATCH] qemu: pass the information when disks are read-only

On Thu, Mar 11, 2010 at 06:14:01PM +0100, Daniel Veillard wrote: > The problem is that even when the user indicates that a drive has to be > opened as read-only (for example a cd-rom) qemu didn't get the > information and tried to open read-write. This could get really nasty > in case SELinux is monitoring that no read-write access is attempted: > > https://bugzilla.redhat.com/show_bug.cgi?id=536760 > > Patch is relatively simple and based on teh assumption that if the > -device qemu options are allowed then qemu also knows about the > readonly option (this was added to the help string quite later so > we should not rely on that in this case). > > * src/qemu/qemu_conf.c: add the ",readonly=on" for read-only disks > and also parse it back in qemuParseCommandLineDisk() > * tests/qemuxml2argvtest.c > tests/qemuxml2argvdata/qemuxml2argv-disk-drive-readonly-disk.args > tests/qemuxml2argvdata/qemuxml2argv-disk-drive-readonly-disk.xml: > add a specific regression test > > diff --git a/src/qemu/qemu_conf.c b/src/qemu/qemu_conf.c > index 40ca221..fb23c52 100644 > --- a/src/qemu/qemu_conf.c > +++ b/src/qemu/qemu_conf.c > @@ -2398,6 +2398,9 @@ qemuBuildDriveStr(virDomainDiskDefPtr disk, > if (bootable && > disk->device == VIR_DOMAIN_DISK_DEVICE_DISK) > virBufferAddLit(&opt, ",boot=on"); > + if (disk->readonly && > + qemuCmdFlags & QEMUD_CMD_FLAG_DEVICE) > + virBufferAddLit(&opt, ",readonly=on"); > if (disk->driverType && > disk->type != VIR_DOMAIN_DISK_TYPE_DIR && > qemuCmdFlags & QEMUD_CMD_FLAG_DRIVE_FORMAT) > @@ -4694,6 +4697,9 @@ qemuParseCommandLineDisk(const char *val, > _("cannot parse drive unit '%s'"), val); > goto cleanup; > } > + } else if (STREQ(keywords[i], "readonly")) { > + if ((values[i] == NULL) || STREQ(values[i], "on")) > + def->readonly = 1; > } > } > > diff --git a/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-readonly-disk.args b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-readonly-disk.args > new file mode 100644 > index 0000000..fbc3226 > --- /dev/null > +++ b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-readonly-disk.args > @@ -0,0 +1 @@ > +LC_ALL=C PATH=/bin HOME=/home/test USER=test LOGNAME=test /usr/bin/qemu -S -M pc -m 214 -smp 1 -nographic -nodefaults -monitor unix:/tmp/test-monitor,server,nowait -no-acpi -boot c -drive file=/dev/HostVG/QEMUGuest1,if=none,id=drive-ide0-0-0 -device ide-drive,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0 -drive file=/dev/sr0,if=none,media=cdrom,id=drive-ide0-1-0,readonly=on -device ide-drive,bus=ide.1,unit=0,drive=drive-ide0-1-0,id=ide0-1-0 -usb -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x3 > diff --git a/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-readonly-disk.xml b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-readonly-disk.xml > new file mode 100644 > index 0000000..39c3a1c > --- /dev/null > +++ b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-readonly-disk.xml > @@ -0,0 +1,30 @@ > +<domain type='qemu'> > + <name>QEMUGuest1</name> > + <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid> > + <memory>219200</memory> > + <currentMemory>219200</currentMemory> > + <vcpu>1</vcpu> > + <os> > + <type arch='i686' machine='pc'>hvm</type> > + <boot dev='hd'/> > + </os> > + <clock offset='utc'/> > + <on_poweroff>destroy</on_poweroff> > + <on_reboot>restart</on_reboot> > + <on_crash>destroy</on_crash> > + <devices> > + <emulator>/usr/bin/qemu</emulator> > + <disk type='block' device='disk'> > + <source dev='/dev/HostVG/QEMUGuest1'/> > + <target dev='hda' bus='ide'/> > + <address type='drive' controller='0' bus='0' unit='0'/> > + </disk> > + <disk type='block' device='cdrom'> > + <source dev='/dev/sr0'/> > + <target dev='hdc' bus='ide'/> > + <readonly/> > + <address type='drive' controller='0' bus='1' unit='0'/> > + </disk> > + <controller type='ide' index='0'/> > + </devices> > +</domain> > diff --git a/tests/qemuxml2argvtest.c b/tests/qemuxml2argvtest.c > index 4ca946a..e3762c9 100644 > --- a/tests/qemuxml2argvtest.c > +++ b/tests/qemuxml2argvtest.c > @@ -249,6 +249,8 @@ mymain(int argc, char **argv) > QEMUD_CMD_FLAG_DRIVE_BOOT | QEMUD_CMD_FLAG_DRIVE_FORMAT); > DO_TEST("disk-drive-fat", QEMUD_CMD_FLAG_DRIVE | > QEMUD_CMD_FLAG_DRIVE_BOOT | QEMUD_CMD_FLAG_DRIVE_FORMAT); > + DO_TEST("disk-drive-readonly-disk", QEMUD_CMD_FLAG_DRIVE | > + QEMUD_CMD_FLAG_DEVICE); > DO_TEST("disk-drive-fmt-qcow", QEMUD_CMD_FLAG_DRIVE | > QEMUD_CMD_FLAG_DRIVE_BOOT | QEMUD_CMD_FLAG_DRIVE_FORMAT); > DO_TEST("disk-drive-shared", QEMUD_CMD_FLAG_DRIVE | > ACK, good to finally have this done