[libvirt] [PATCH 1/4] qemu: Add checking in helpers for sgio setting
Osier Yang
jyang at redhat.com
Mon Feb 11 11:09:29 UTC 2013
On 2013年02月11日 18:48, Daniel P. Berrange wrote:
> On Mon, Feb 11, 2013 at 06:35:42PM +0800, Osier Yang wrote:
>> On 2013年02月09日 04:21, John Ferlan wrote:
>>> On 02/08/2013 08:07 AM, Osier Yang wrote:
>>>> This moves the checking into the helpers, to avoid the
>>>> callers missing the checking.
>>>> ---
>>>> src/qemu/qemu_conf.c | 20 ++++++++++++++++----
>>>> src/qemu/qemu_conf.h | 4 ++--
>>>> src/qemu/qemu_driver.c | 18 +++++++-----------
>>>> src/qemu/qemu_process.c | 21 ++++++++++++---------
>>>> 4 files changed, 37 insertions(+), 26 deletions(-)
>>>>
>>>> diff --git a/src/qemu/qemu_conf.c b/src/qemu/qemu_conf.c
>>>> index 17f7d45..69ba710 100644
>>>> --- a/src/qemu/qemu_conf.c
>>>> +++ b/src/qemu/qemu_conf.c
>>>> @@ -726,12 +726,20 @@ qemuGetSharedDiskKey(const char *disk_path)
>>>> */
>>>> int
>>>> qemuAddSharedDisk(virHashTablePtr sharedDisks,
>>>> - const char *disk_path)
>>>> + virDomainDiskDefPtr disk)
>>>> {
>>>> size_t *ref = NULL;
>>>> char *key = NULL;
>>>>
>>>> - if (!(key = qemuGetSharedDiskKey(disk_path)))
>>>> + /* Currently the only conflicts we have to care about
>>>> + * for the shared disk is "sgio" setting, which is only
>>>> + * valid for block disk.
>>>> + */
>>>> + if (disk->type != VIR_DOMAIN_DISK_TYPE_BLOCK ||
>>>> + !disk->shared || !disk->src)
>>>> + return 0;
>>>> +
>>>> + if (!(key = qemuGetSharedDiskKey(disk->src)))
>>>> return -1;
>>>>
>>>> if ((ref = virHashLookup(sharedDisks, key))) {
>>>> @@ -755,12 +763,16 @@ qemuAddSharedDisk(virHashTablePtr sharedDisks,
>>>> */
>>>> int
>>>> qemuRemoveSharedDisk(virHashTablePtr sharedDisks,
>>>> - const char *disk_path)
>>>> + virDomainDiskDefPtr disk)
>>>> {
>>>> size_t *ref = NULL;
>>>> char *key = NULL;
>>>>
>>>> - if (!(key = qemuGetSharedDiskKey(disk_path)))
>>>> + if (disk->type != VIR_DOMAIN_DISK_TYPE_BLOCK ||
>>>> + !disk->shared || !disk->src)
>>>> + return 0;
>>
>> [2]
>>
>>>> +
>>>> + if (!(key = qemuGetSharedDiskKey(disk->src)))
>>>> return -1;
>>>>
>>>> if (!(ref = virHashLookup(sharedDisks, key))) {
>>>> diff --git a/src/qemu/qemu_conf.h b/src/qemu/qemu_conf.h
>>>> index 60c4109..8e84bcf 100644
>>>> --- a/src/qemu/qemu_conf.h
>>>> +++ b/src/qemu/qemu_conf.h
>>>> @@ -270,11 +270,11 @@ void qemuDriverCloseCallbackRunAll(virQEMUDriverPtr driver,
>>>> virConnectPtr conn);
>>>>
>>>> int qemuAddSharedDisk(virHashTablePtr sharedDisks,
>>>> - const char *disk_path)
>>>> + virDomainDiskDefPtr disk)
>>>> ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2);
>>>>
>>>> int qemuRemoveSharedDisk(virHashTablePtr sharedDisks,
>>>> - const char *disk_path)
>>>> + virDomainDiskDefPtr disk)
>>>> ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2);
>>>> char * qemuGetSharedDiskKey(const char *disk_path)
>>>> ATTRIBUTE_NONNULL(1);
>>>> diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
>>>> index 979a027..043efd3 100644
>>>> --- a/src/qemu/qemu_driver.c
>>>> +++ b/src/qemu/qemu_driver.c
>>>> @@ -5855,11 +5855,9 @@ qemuDomainAttachDeviceDiskLive(virConnectPtr conn,
>>>> }
>>>>
>>>> if (ret == 0) {
>>>> - if (disk->type == VIR_DOMAIN_DISK_TYPE_BLOCK&& disk->shared) {
>>>> - if (qemuAddSharedDisk(driver->sharedDisks, disk->src)< 0)
>>>> - VIR_WARN("Failed to add disk '%s' to shared disk table",
>>>> - disk->src);
>>>> - }
>>>> + if (qemuAddSharedDisk(driver->sharedDisks, disk)< 0)
>>>> + VIR_WARN("Failed to add disk '%s' to shared disk table",
>>>> + disk->src);
>>>>
>>>> if (qemuSetUnprivSGIO(disk)< 0)
>>>> VIR_WARN("Failed to set unpriv_sgio of disk '%s'", disk->src);
>>>
>>> Does there need to be a NULLSTR(disk->src)? Doesn't seem so, but just
>>> checking. I only note this because the qemuAddSharedDisk() has a
>>> !disk->src check prior to returning zero.
>>
>> qemuSetUnprivSGIO returns 0 as long as disk->src is NULL too. See [1].
>
> If disk->type == NETWORK, then de-referencing disk->src has potential to
> SEGV the entire process, since that field is not valid.
There is checking in this version:
/* "sgio" is only valid for block disk; cdrom
* and floopy disk can have empty source.
*/
if (disk->type != VIR_DOMAIN_DISK_TYPE_BLOCK ||
!disk->src)
return 0;
So for a network disk, it has no chance to de-reference disk->src
if the return value < 0.
>>
>>>
>>>> @@ -5980,12 +5978,10 @@ qemuDomainDetachDeviceDiskLive(virQEMUDriverPtr driver,
>>>> break;
>>>> }
>>>>
>>>> - if (ret == 0&&
>>>> - disk->type == VIR_DOMAIN_DISK_TYPE_BLOCK&&
>>>> - disk->shared) {
>>>> - if (qemuRemoveSharedDisk(driver->sharedDisks, disk->src)< 0)
>>>> - VIR_WARN("Failed to remove disk '%s' from shared disk table",
>>>> - disk->src);
>>>> + if (ret == 0) {
>>>> + if (qemuRemoveSharedDisk(driver->sharedDisks, disk)< 0)
>>>> + VIR_WARN("Failed to remove disk '%s' from shared disk table",
>>>> + disk->src);
>>>
>>> Similar comment here w/r/t NULLSTR and checks in Remove code
>>
>> Likewise. See [2].
>
> Again you must *not* de-reference disk->src without first validating
> the disk->type value.
>
Likewise.
>
> Daniel
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