[libvirt] [PATCH 1/1] Fix the crash when seclable is freed

Osier Yang jyang at redhat.com
Tue Apr 2 08:45:52 UTC 2013


On 02/04/13 16:04, Li Zhang wrote:
> On 2013年04月02日 15:03, Li Zhang wrote:
>> On 2013年04月02日 14:47, Osier Yang wrote:
>>> On 02/04/13 13:58, Li Zhang wrote:
>>>> From: Li Zhang <zhlcindy at linux.vnet.ibm.com>
>>>>
>>>> When seclabel's type is VIR_DOMAIN_SECLABEL_NONE,
>>>> virSecurityLabelDefPtr's members are not allocated.
>>>> So it will cause crash when calling VIR_FREE.
>>>>
>>>> This problem is found when running autotest on PPC.
>>>>
>>>> Failed to remove cgroup for virt-tests-vm1
>>>> *** glibc detected *** /usr/sbin/libvirtd: free(): invalid pointer: 
>>>> 0x00003fff9c187510 ***
>>>> ======= Backtrace: =========
>>>> /lib64/libc.so.6(+0xb89c4)[0x3fffa9bc89c4]
>>>> /lib64/libvirt.so.0(virFree-0x3e2320)[0x3fffaa82e9c0]
>>>> /lib64/libvirt.so.0(virSecurityLabelDefFree-0x378984)[0x3fffaa89d69c]
>>>> /lib64/libvirt.so.0(virDomainDefFree-0x367c98)[0x3fffaa8ae968]
>>>> /usr/lib64/libvirt/connection-driver/libvirt_driver_qemu.so(qemuProcessStop-0xc85f8)[0x3fffa2899d58] 
>>>>
>>>> /usr/lib64/libvirt/connection-driver/libvirt_driver_qemu.so(+0xc3668)[0x3fffa28e3668] 
>>>>
>>>> /lib64/libvirt.so.0(virDomainDestroy-0x309bd0)[0x3fffaa90f6f0]
>>>> /usr/sbin/libvirtd[0x10035230]
>>>> /lib64/libvirt.so.0(virNetServerProgramDispatch-0x289b50)[0x3fffaa995930] 
>>>>
>>>> /lib64/libvirt.so.0(+0x20db18)[0x3fffaa98db18]
>>>> /lib64/libvirt.so.0(+0xfbd24)[0x3fffaa87bd24]
>>>> /lib64/libvirt.so.0(+0xfaec8)[0x3fffaa87aec8]
>>>> /lib64/libpthread.so.0(+0xc604)[0x3fffa9d7c604]
>>>> /lib64/libc.so.6(clone-0xb8fe4)[0x3fffa9c3f094]
>>>>
>>>> Signed-off-by: Li Zhang <zhlcindy at linux.vnet.ibm.com>
>>>> ---
>>>> src/conf/domain_conf.c | 2 ++
>>>> 1 files changed, 2 insertions(+), 0 deletions(-)
>>>>
>>>> diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
>>>> index f3fca7f..2856660 100644
>>>> --- a/src/conf/domain_conf.c
>>>> +++ b/src/conf/domain_conf.c
>>>> @@ -1006,6 +1006,8 @@ 
>>>> virSecurityLabelDefFree(virSecurityLabelDefPtr def)
>>>> {
>>>> if (!def)
>>>> return;
>>>> + if (def->type == VIR_DOMAIN_SECLABEL_NONE)
>>>> + return;
>>>> VIR_FREE(def->model);
>>>
>>> model is always parsed. So it will be leaked if someone specifies
>>> "model" even the type is "none".
>> Okay, it seems that is not always non-NULL although it is always parsed.
>>
>> My XML file is as:
>> <seclabel type='none'/>
>>
>> It should be better to add if clause before VIR_FREE.
>>
> Sorry, it seems that this is not right solution to resolve the problem.
> free(ptr): ptr can be NULL.
> This root cause is because of invalid pointer which is not NULL.
> I need to find out the invalid pointer.

The solution is not to parse "model" when the seclabel type is "none".
I might not be 100% correct. But I think the "model" is just useless
for "none". Then your patch is right.

>
>>>
>>>> VIR_FREE(def->label);
>>>> VIR_FREE(def->imagelabel);
>>>
>>
>
>




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