9:28 a.m.
We do parse and represent period collection as unsigned int in our
internal structures, however commit
d5c67e7f4523450023b89b69c16472582c85eeaf converts this to int, thus wrapping
around inputs greater than INT_MAX which results in an error from QEMU.
This patch adds a check into QEMU driver, because period attribute is
only supported by QEMU.
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1140958
---
src/qemu/qemu_driver.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index bec05d4..46bd880 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -2414,6 +2414,12 @@ static int qemuDomainSetMemoryStatsPeriod(virDomainPtr dom, int
period,
/* Set the balloon driver collection interval */
priv = vm->privateData;
+ if (period < 0) {
+ virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
+ _("invalid value for collection period"));
+ goto endjob;
+ }
+
if (flags & VIR_DOMAIN_AFFECT_LIVE) {
qemuDomainObjEnterMonitor(driver, vm);
--
1.9.3
1:10 a.m.
On Tue, Feb 24, 2015 at 04:28:18PM +0100, Erik Skultety wrote:
Well, there are couple more things broken.
1) Change to this patch:
It is written in the description that period can me 0 or more, so
it would make sense to guard all the drivers (ideally at one
place) together. If that changes, the check can be moved to
individual drivers, but for now anything outside <0,INT_MAX>
doesn't make sense.
2) Curiosity:
<membaloon model='virtio'>
<stats period='5'/>
<address .../>
</membaloon>
This ^^ fails validation because <stats/> must come *after*
<address/> (WAT) even though all other device elements *require*
the address to be last (why would we even do that!).
3) Invalid number gets still parsed in the XML and it only wraps to
negative when sending to the monitor at the guest's start.
Since these are all small things, I expect them to be fixed as well
(be sure the BZ will come back anyway if you don't do that :) ),
although not necessarily in the same commit. One note: we must be
able to parse old XMLs, so you can either reject the number at start
(more pain then security) or you can just make period < 0 behave like
period == 0 or many other variants. You might even wrap everything to
unsigned as it is unsigned in qemu anyways. The other thing you can't
do is to fix our API without creating a new one. I wonder if wraping
negative values could be written in the docs so we have more options.
But anyway, who's going to request stats gathering period greater than
68 years except QE, right? ;)
6:25 a.m.
On 02/25/2015 02:10 AM, Martin Kletzander wrote:
correct... for that matter a really long period doesn't make much sense,
but if someone wants one, then they can have it...
Probably because I was still getting used to the XML/RNG
formatting/syntax "rules".... This would be easily dealt with by an
<interleave .../>, right? Then again, review missed it too ;-)
The input parsing for that value was created (or copied from some other
attribute) before the virStrToLong_ui[p] API's were created... I think
at the time those API's were created there was a comment about maybe
spending some cycles looking at all the various parsed 'int' or 'uint'
attributes to convert them to use the newer API, but that never got
anywhere.
John
10:42 a.m.
On 02/25/2015 08:10 AM, Martin Kletzander wrote:
Well stats collection period is only used by QEMU, but the issue here is
it's quite impossible to do it unified for all drivers, possibly at one
place, because you can't do it right after the domain gets parsed
(otherwise domain disappears after daemon's restart) and we already do
check this at client's side (both virsh cmd routine and our public API
virDomainSetMemoryStatsPeriod). However, this patch doesn't fix the
issue anyway, as the check is at a wrong place.
Will include fix for this one in the next versions :).
3) Invalid number gets still parsed in the XML and it only wraps to
negative when sending to the monitor at the guest's start.
We can't do much about this, can we?
Thank you for your review :),
Erik
1:49 a.m.
On Thu, Feb 26, 2015 at 05:42:10PM +0100, Erik Skultety wrote:
You're right, I didn't know we have checks in APIs on the way already.
Great! That'd be nice (although it's not an error per se).
Sure we can, the question is whether that makes sense. I'd either
shout at the time when qemu is starting the domain and fail when int
period <= 0 or ignore such values quietly (with VIR_DEBUG() at most).
When it comes to where to check this, it'd be best to check this
inside qemuMonitorSetMemoryStatsPeriod(), but beware! We are screwing
up the error messages all over the place and leaving them, duplicating
them, etc. So even though I'd accept a simple fix in that function,
I'd like to see (at least later on) some cleanup to this.
Thank you for your review :),
Erik
You're welcome ;)
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Martin Kletzander