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Re: [libvirt] [PATCH] pci: initialize virtual_functions array pointer to avoid segfault



On 07/01/2013 12:21 AM, Daniel Veillard wrote:
> On Mon, Jul 01, 2013 at 12:01:28AM -0400, Laine Stump wrote:
>> This fixes https://bugzilla.redhat.com/show_bug.cgi?id=971325
>>
>> The problem was that if virPCIGetVirtualFunctions was given the name
>> of a non-existent interface, it would return to its caller without
>> initializing the pointer to the array of virtual functions to NULL,
>> and the caller (virNetDevGetVirtualFunctions) would try to VIR_FREE()
>> the invalid pointer.
>>
>> The final error message before the crash would be:
>>
>>  virPCIGetVirtualFunctions:2088 :
>>   Failed to open dir '/sys/class/net/eth2/device':
>>   No such file or directory
>>
>> In this patch I move the initialization in virPCIGetVirtualFunctions()
>> to the begining of the function, and also do an explicit
>> initialization in virNetDevGetVirtualFunctions, just in case someone
>> in the future adds code into that function prior to the call to
>> virPCIGetVirtualFunctions.
>> ---
>>  src/util/virnetdev.c | 3 +++
>>  src/util/virpci.c    | 5 +++--
>>  2 files changed, 6 insertions(+), 2 deletions(-)
>>
>> diff --git a/src/util/virnetdev.c b/src/util/virnetdev.c
>> index ebe20d0..5e8dffb 100644
>> --- a/src/util/virnetdev.c
>> +++ b/src/util/virnetdev.c
>> @@ -1100,6 +1100,9 @@ virNetDevGetVirtualFunctions(const char *pfname,
>>      char *pci_sysfs_device_link = NULL;
>>      char *pciConfigAddr = NULL;
>>  
>> +    *virt_fns = NULL;
>> +    *n_vfname = 0;
>> +
>>      if (virNetDevSysfsFile(&pf_sysfs_device_link, pfname, "device") < 0)
>>          return ret;
>>  
>> diff --git a/src/util/virpci.c b/src/util/virpci.c
>> index 2acab1a..15de3f9 100644
>> --- a/src/util/virpci.c
>> +++ b/src/util/virpci.c
>> @@ -2449,6 +2449,9 @@ virPCIGetVirtualFunctions(const char *sysfs_path,
>>      VIR_DEBUG("Attempting to get SR IOV virtual functions for device"
>>                "with sysfs path '%s'", sysfs_path);
>>  
>> +    *virtual_functions = NULL;
>> +    *num_virtual_functions = 0;
>> +
>>      dir = opendir(sysfs_path);
>>      if (dir == NULL) {
>>          memset(errbuf, '\0', sizeof(errbuf));
>> @@ -2458,8 +2461,6 @@ virPCIGetVirtualFunctions(const char *sysfs_path,
>>          return ret;
>>      }
>>  
>> -    *virtual_functions = NULL;
>> -    *num_virtual_functions = 0;
>>      while ((entry = readdir(dir))) {
>>          if (STRPREFIX(entry->d_name, "virtfn")) {
>>              virPCIDeviceAddress *config_addr = NULL;
>> -- 
>> 1.7.11.7
>   ACK,
>

Pushed. Thanks!


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