[libvirt] [PATCH 3/3] virISCSIGetSession: Don't leak memory

[Michal Privoznik]

On 04/05/2017 10:34 PM, John Ferlan wrote:
> 
> 
> On 04/05/2017 04:16 PM, Martin Kletzander wrote:
>> On Wed, Apr 05, 2017 at 03:11:52PM -0400, John Ferlan wrote:
>>>
>>>
>>> On 04/05/2017 04:50 AM, Michal Privoznik wrote:
>>>> This function runs an iscsi command and parses its output.
>>>> However, due to the nature of things, virISCSIExtractSession()
>>>> callback can be called multiple times. In each run it would
>>>> allocate new memory and overwrite the variable where we keep
>>>> pointer to it and thus leaking old allocations.
>>>>
>>>> Signed-off-by: Michal Privoznik <mprivozn at redhat.com>
>>>> ---
>>>>  src/util/viriscsi.c | 3 ++-
>>>>  1 file changed, 2 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/src/util/viriscsi.c b/src/util/viriscsi.c
>>>> index 504ffbd..9c6fde0 100644
>>>> --- a/src/util/viriscsi.c
>>>> +++ b/src/util/viriscsi.c
>>>> @@ -52,7 +52,8 @@ virISCSIExtractSession(char **const groups,
>>>>  {
>>>>      struct virISCSISessionData *data = opaque;
>>>>
>>>> -    if (STREQ(groups[1], data->devpath))
>>>> +    if (!data->devpath &&
>>>> +        STREQ(groups[1], data->devpath))
>>>>          return VIR_STRDUP(data->session, groups[0]);
>>>>      return 0;
>>>>  }
>>>>
>>>
>>> I see you fixed your typo "!data->devpath" to "!data->session" before
>>
>> I wonder how I missed that, maybe because this wasn't the first time I
>> saw the patch O:-)
>>
>>> pushing, but the reality is this is a no-op considering at most we can
>>> only match once, but because virCommandRunRegex only bails if the return
>>
>> It is not no-op.  The function is ran on every line of output and, as
>> we've noticed on Michal's machine, he got 2 lines with the same
>> group[1], so to speak.
>>
> 
> So what's the output from a "iscsiadm --mode session" on Michal's
> machine?  And then if there is a duplicate - how did it happen?

# iscsiadm --mode session
tcp: [31] 10.34.126.253:3260,1 iqn.2017-03.com.mprivozn:server
tcp: [32] virt-iscsi-server.usersys.redhat.com:3260,1 iqn.2017-03.com.mprivozn:server

where the URL from "line" [32] resolves to the IP from "line" [31].

Michal