[libvirt] [PATCH 2/3] virnetsocket: Resolve Coverity RESOURCE_LEAK

[John Ferlan]

On 08/22/2014 11:49 AM, Michal Privoznik wrote:
> On 22.08.2014 17:28, John Ferlan wrote:
>> Since '1b807f92d' - Coverity complains that in the error paths of
>> both virFork() and virProcessWait() that the 'passfd' will not be closed
>>
>> Signed-off-by: John Ferlan <jferlan at redhat.com>
>> ---
>>   src/rpc/virnetsocket.c | 8 ++++++--
>>   1 file changed, 6 insertions(+), 2 deletions(-)
>>
>> diff --git a/src/rpc/virnetsocket.c b/src/rpc/virnetsocket.c
>> index f913365..ce908fa 100644
>> --- a/src/rpc/virnetsocket.c
>> +++ b/src/rpc/virnetsocket.c
>> @@ -593,8 +593,10 @@ int virNetSocketNewConnectUNIX(const char *path,
>>            * behaviour on sockets according to POSIX, so it doesn't
>>            * work outside Linux.
>>            */
>> -        if ((pid = virFork()) < 0)
>> +        if ((pid = virFork()) < 0) {
>> +            VIR_FORCE_CLOSE(passfd);
>>               goto error;
>> +        }
>>   
>>           if (pid == 0) {
>>               umask(0077);
>> @@ -604,8 +606,10 @@ int virNetSocketNewConnectUNIX(const char *path,
>>               _exit(EXIT_SUCCESS);
>>           }
>>   
>> -        if (virProcessWait(pid, &status, false) < 0)
>> +        if (virProcessWait(pid, &status, false) < 0) {
>> +            VIR_FORCE_CLOSE(passfd);
>>               goto error;
>> +        }
>>   
>>           if (status != EXIT_SUCCESS) {
>>               /*
>>
> 
> Unfortunately not enough context is shown to express myself, so I'll paste interesting knobs from the function:
> 
>         if (listen(passfd, 0) < 0) {
>              virReportSystemError(errno, "%s",
>                                   _("Failed to listen on socket that's about "
>                                     "to be passed to the daemon"));
>              goto error;
>          }
>  
>          if (connect(fd, &remoteAddr.data.sa, remoteAddr.len) < 0) {
>              virReportSystemError(errno, _("Failed to connect socket to '%s'"),
>                                   path);
>              goto error;
>          }
>  
>          if (virNetSocketForkDaemon(binary, passfd) < 0)
>              goto error;
>      }
>  
>      localAddr.len = sizeof(localAddr.data);
>      if (getsockname(fd, &localAddr.data.sa, &localAddr.len) < 0) {
>          virReportSystemError(errno, "%s", _("Unable to get local socket name"));
>          goto error;
>      }
>  
>      if (!(*retsock = virNetSocketNew(&localAddr, &remoteAddr, true, fd, -1, 0)))
>          goto error;
>  
>      return 0;
>  
>   error:
>      VIR_FREE(buf);
>      VIR_FORCE_CLOSE(fd);
>      if (spawnDaemon)
>          unlink(path);
>      return -1;
>  }
> 
> 
> Here, if any of listen() or connect() fail, the control continues on the error label and the @passfd is leaked again.
> virNetSocketForkDaemon() is different - it closes passfd on failure. So I suggest moving VIR_FORCE_CLOSE() under the error label.
> 

Yeah - Coverity only complained about the two paths - so I was hesitant
to put the VIR_FORCE_CLOSE(passfd) in the error: path...

In any case, putting it the error: path does resolve the issue as well
as making sure to initialize passfd = -1 (initializing fd = -1 wasn't
necessary since there's currently no way to error unless it's set)

John