On Fri, Apr 12, 2019 at 03:32:21PM +0200, Martin Kletzander wrote:
This does not cause a problem in usual scenarios thanks to us
allowing
CAP_DAC_OVERRIDE for the qemu process, however in some scenarios this might be
an issue because the directory is created with mkdtemp(3) which explicitly
creates that with 0700 permissions and qemu running as non-root cannot access
that.
The scenarios include:
- Builds without CAPNG
This makes sense, since we're unable to give QEMU CAP_DAC_OVERRIDE
- Running libvirtd in a container [1]
I'm rather puzzelled why this is a problem unless libvirtd itself
lacks permissions to give CAP_DAC_OVERRIDE, but if that was the
case I would have expected an error from capng when trying to
grant it/.
- and possibly others.
[1]
https://github.com/kubevirt/kubevirt/pull/2181#issuecomment-481840304
Signed-off-by: Martin Kletzander <mkletzan(a)redhat.com>
---
src/qemu/qemu_process.c | 16 ++++++++++++++++
1 file changed, 16 insertions(+)
diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
index 47d8ca2ff163..2e2c4812fef7 100644
--- a/src/qemu/qemu_process.c
+++ b/src/qemu/qemu_process.c
@@ -8447,6 +8447,19 @@ qemuProcessQMPNew(const char *binary,
}
+static int
+qemuProcessQEMULabelUniqPath(qemuProcessQMPPtr proc) {
+ /* We cannot use the security driver here, but we should not need to. */
+ if (chown(proc->uniqDir, proc->runUid, -1) < 0) {
+ virReportSystemError(errno,
+ "Cannot chown uniq path: %s", proc->uniqDir);
+ return -1;
+ }
+
+ return 0;
+}
+
+
static int
qemuProcessQMPInit(qemuProcessQMPPtr proc)
{
@@ -8466,6 +8479,9 @@ qemuProcessQMPInit(qemuProcessQMPPtr proc)
goto cleanup;
}
+ if (qemuProcessQEMULabelUniqPath(proc) < 0)
+ goto cleanup;
+
if (virAsprintf(&proc->monpath, "%s/%s", proc->uniqDir,
"qmp.monitor") < 0)
goto cleanup;
--
2.21.0
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Regards,
Daniel
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