[libvirt] [PATCH] Fix a crash when using Open vSwitch virtual ports

[Alex Jia]

On 08/30/2012 01:49 PM, Daniel Veillard wrote:


Daniel, BTW, To test this patch again, it works for me :)

> On Wed, Aug 29, 2012 at 02:44:36PM -0400, Kyle Mestery wrote:
>> Fixup buffer usage when handling VLANs. Also fix the logic
>> used to determine if the virNetDevVlanPtr is valid or not.
>> Fixes crashes in the latest code when using Open vSwitch
>> virtualports.
>>
>> Signed-off-by: Kyle Mestery<kmestery at cisco.com>
>> ---
>>   src/util/virnetdevopenvswitch.c | 26 +++++++++++++-------------
>>   1 file changed, 13 insertions(+), 13 deletions(-)
>>
>> diff --git a/src/util/virnetdevopenvswitch.c b/src/util/virnetdevopenvswitch.c
>> index b903ae4..cdbc5ef 100644
>> --- a/src/util/virnetdevopenvswitch.c
>> +++ b/src/util/virnetdevopenvswitch.c
>> @@ -59,7 +59,7 @@ int virNetDevOpenvswitchAddPort(const char *brname, const char *ifname,
>>       char *ifaceid_ex_id = NULL;
>>       char *profile_ex_id = NULL;
>>       char *vmid_ex_id = NULL;
>> -    virBufferPtr buf;
>> +    virBuffer buf = VIR_BUFFER_INITIALIZER;
>>
>>       virMacAddrFormat(macaddr, macaddrstr);
>>       virUUIDFormat(ovsport->interfaceID, ifuuidstr);
>> @@ -79,13 +79,12 @@ int virNetDevOpenvswitchAddPort(const char *brname, const char *ifname,
>>                           ovsport->profileID)<  0)
>>               goto out_of_memory;
>>       }
>> -    if (virtVlan) {
>> -        if (VIR_ALLOC(buf)<  0)
>> -            goto out_of_memory;
>> +
>> +    if (virtVlan&&  virtVlan->nTags>  0) {
>>
>>           /* Trunk port first */
>> -        if (virtVlan->trunk) {
>> -            virBufferAddLit(buf, "trunk=");
>> +        if (virtVlan->trunk == true) {
>> +            virBufferAddLit(&buf, "trunk=");
>>
>>               /*
>>                * Trunk ports have at least one VLAN. Do the first one
>> @@ -93,21 +92,21 @@ int virNetDevOpenvswitchAddPort(const char *brname, const char *ifname,
>>                * start of the for loop if there are more than one VLANs
>>                * on this trunk port.
>>                */
>> -            virBufferAsprintf(buf, "%d", virtVlan->tag[i]);
>> +            virBufferAsprintf(&buf, "%d", virtVlan->tag[i]);
>>
>>               for (i = 1; i<  virtVlan->nTags; i++) {
>> -                virBufferAddLit(buf, ",");
>> -                virBufferAsprintf(buf, "%d", virtVlan->tag[i]);
>> +                virBufferAddLit(&buf, ",");
>> +                virBufferAsprintf(&buf, "%d", virtVlan->tag[i]);
>>               }
>>           } else if (virtVlan->nTags) {
>> -            virBufferAsprintf(buf, "tag=%d", virtVlan->tag[0]);
>> +            virBufferAsprintf(&buf, "tag=%d", virtVlan->tag[0]);
>>           }
>>       }
>>
>>       cmd = virCommandNew(OVSVSCTL);
>>       if (ovsport->profileID[0] == '\0') {
>>           virCommandAddArgList(cmd, "--", "--may-exist", "add-port",
>> -                        brname, ifname, virBufferContentAndReset(buf),
>> +                        brname, ifname, virBufferCurrentContent(&buf),
>>                           "--", "set", "Interface", ifname, attachedmac_ex_id,
>>                           "--", "set", "Interface", ifname, ifaceid_ex_id,
>>                           "--", "set", "Interface", ifname, vmid_ex_id,
>> @@ -116,7 +115,7 @@ int virNetDevOpenvswitchAddPort(const char *brname, const char *ifname,
>>                           NULL);
>>       } else {
>>           virCommandAddArgList(cmd, "--", "--may-exist", "add-port",
>> -                        brname, ifname, virBufferContentAndReset(buf),
>> +                        brname, ifname, virBufferCurrentContent(&buf),
>>                           "--", "set", "Interface", ifname, attachedmac_ex_id,
>>                           "--", "set", "Interface", ifname, ifaceid_ex_id,
>>                           "--", "set", "Interface", ifname, vmid_ex_id,
>> @@ -135,7 +134,8 @@ int virNetDevOpenvswitchAddPort(const char *brname, const char *ifname,
>>
>>       ret = 0;
>>   cleanup:
>> -    VIR_FREE(buf);
>> +    if (virBufferUse(&buf)>  0)
>> +        virBufferFreeAndReset(&buf);
>    that looks fine up to here, where we could leak in theory,
>    virBufferUse() return the amount of bytes used in the buffer, not
>    if the buffer was allocated. Sounds to me we can use
>    virBufferFreeAndReset() directly without the test
>
>>       VIR_FREE(attachedmac_ex_id);
>>       VIR_FREE(ifaceid_ex_id);
>>       VIR_FREE(vmid_ex_id);
>    I pushed with that small change,
>
>     thanks !
>
> Daniel
>