diff mbox

[dpdk-dev] vfio: fix close unchecked file descriptor

Message ID 1505901573-463-1-git-send-email-kubax.kozak@intel.com (mailing list archive)
State Superseded, archived
Headers

Checks

Context Check Description
ci/checkpatch success coding style OK
ci/Intel-compilation success Compilation OK

Commit Message

Kuba Kozak Sept. 20, 2017, 9:59 a.m. UTC 
  Add file descriptor value check before calling close() function.

Coverity issue: 141297
Fixes: 811b6b25060f ("vfio: fix file descriptor leak in multi-process")
Cc: patrick@patrickmacarthur.net
Cc: stable@dpdk.org

Signed-off-by: Kuba Kozak <kubax.kozak@intel.com>
---
 lib/librte_eal/linuxapp/eal/eal_vfio_mp_sync.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Comments

Anatoly Burakov Sept. 20, 2017, 10:15 a.m. UTC | #1 
On 20-Sep-17 10:59 AM, Kuba Kozak wrote:
> Add file descriptor value check before calling close() function.
> 
> Coverity issue: 141297
> Fixes: 811b6b25060f ("vfio: fix file descriptor leak in multi-process")
> Cc: patrick@patrickmacarthur.net
> Cc: stable@dpdk.org
> 
> Signed-off-by: Kuba Kozak <kubax.kozak@intel.com>
> ---

Acked-by: Anatoly Burakov <anatoly.burakov@intel.com>
Patrick MacArthur Sept. 20, 2017, 2:34 p.m. UTC | #2 
On 09/20/2017 05:59 AM, Kuba Kozak wrote:
> Add file descriptor value check before calling close() function.
> 
> Coverity issue: 141297
> Fixes: 811b6b25060f ("vfio: fix file descriptor leak in multi-process")
> Cc: patrick@patrickmacarthur.net
> Cc: stable@dpdk.org
> 
> Signed-off-by: Kuba Kozak <kubax.kozak@intel.com>
> ---
>   lib/librte_eal/linuxapp/eal/eal_vfio_mp_sync.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/lib/librte_eal/linuxapp/eal/eal_vfio_mp_sync.c b/lib/librte_eal/linuxapp/eal/eal_vfio_mp_sync.c
> index 7e8095c..c04f548 100644
> --- a/lib/librte_eal/linuxapp/eal/eal_vfio_mp_sync.c
> +++ b/lib/librte_eal/linuxapp/eal/eal_vfio_mp_sync.c
> @@ -301,7 +301,8 @@ vfio_mp_sync_thread(void __rte_unused * arg)
>   				vfio_mp_sync_send_request(conn_sock, SOCKET_ERR);
>   			else
>   				vfio_mp_sync_send_fd(conn_sock, fd);
> -			close(fd);
> +			if (fd != -1)
> +				close(fd);

IMHO this should be:

         if (fd >= 0)

What specifically is Coverity complaining about here? Is there a 
specific code path that leads to fd being -1 here?

Thanks,
Patrick MacArthur
Anatoly Burakov Sept. 20, 2017, 2:39 p.m. UTC | #3 
On 20-Sep-17 3:34 PM, Patrick MacArthur wrote:
> On 09/20/2017 05:59 AM, Kuba Kozak wrote:
>> Add file descriptor value check before calling close() function.
>>
>> Coverity issue: 141297
>> Fixes: 811b6b25060f ("vfio: fix file descriptor leak in multi-process")
>> Cc: patrick@patrickmacarthur.net
>> Cc: stable@dpdk.org
>>
>> Signed-off-by: Kuba Kozak <kubax.kozak@intel.com>
>> ---
>>   lib/librte_eal/linuxapp/eal/eal_vfio_mp_sync.c | 3 ++-
>>   1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/lib/librte_eal/linuxapp/eal/eal_vfio_mp_sync.c 
>> b/lib/librte_eal/linuxapp/eal/eal_vfio_mp_sync.c
>> index 7e8095c..c04f548 100644
>> --- a/lib/librte_eal/linuxapp/eal/eal_vfio_mp_sync.c
>> +++ b/lib/librte_eal/linuxapp/eal/eal_vfio_mp_sync.c
>> @@ -301,7 +301,8 @@ vfio_mp_sync_thread(void __rte_unused * arg)
>>                   vfio_mp_sync_send_request(conn_sock, SOCKET_ERR);
>>               else
>>                   vfio_mp_sync_send_fd(conn_sock, fd);
>> -            close(fd);
>> +            if (fd != -1)
>> +                close(fd);
> 
> IMHO this should be:
> 
>          if (fd >= 0)
> 
> What specifically is Coverity complaining about here? Is there a 
> specific code path that leads to fd being -1 here?
> 
Hi Patrick,

There's no way the fd will be 0 - the function we get the value from 
returns a valid fd, or a -1 in case of error. In this particular case, 
the "specific code path that leads to fd being -1" is when we can't get 
a container fd for some reason. I believe this is a very remote 
possibility as by the time we're spinning up the socket listening thread 
we're pretty sure we have a working VFIO container, but this is a valid 
fix nevertheless. Maybe having it >= 0 (or > 0, to be precise) would be 
cleaner, but it really makes no difference here.
Patrick MacArthur Sept. 21, 2017, 2:28 a.m. UTC | #4 
On 09/20/2017 10:39 AM, Burakov, Anatoly wrote:
> On 20-Sep-17 3:34 PM, Patrick MacArthur wrote:
>> On 09/20/2017 05:59 AM, Kuba Kozak wrote:
>>> Add file descriptor value check before calling close() function.
>>>
>>> Coverity issue: 141297
>>> Fixes: 811b6b25060f ("vfio: fix file descriptor leak in multi-process")
>>> Cc: patrick@patrickmacarthur.net
>>> Cc: stable@dpdk.org
>>>
>>> Signed-off-by: Kuba Kozak <kubax.kozak@intel.com>
>>> ---
>>>   lib/librte_eal/linuxapp/eal/eal_vfio_mp_sync.c | 3 ++-
>>>   1 file changed, 2 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/lib/librte_eal/linuxapp/eal/eal_vfio_mp_sync.c 
>>> b/lib/librte_eal/linuxapp/eal/eal_vfio_mp_sync.c
>>> index 7e8095c..c04f548 100644
>>> --- a/lib/librte_eal/linuxapp/eal/eal_vfio_mp_sync.c
>>> +++ b/lib/librte_eal/linuxapp/eal/eal_vfio_mp_sync.c
>>> @@ -301,7 +301,8 @@ vfio_mp_sync_thread(void __rte_unused * arg)
>>>                   vfio_mp_sync_send_request(conn_sock, SOCKET_ERR);
>>>               else
>>>                   vfio_mp_sync_send_fd(conn_sock, fd);
>>> -            close(fd);
>>> +            if (fd != -1)
>>> +                close(fd);
>>
>> IMHO this should be:
>>
>>          if (fd >= 0)
>>
>> What specifically is Coverity complaining about here? Is there a 
>> specific code path that leads to fd being -1 here?
>>
> Hi Patrick,
> 
> There's no way the fd will be 0 - the function we get the value from 
> returns a valid fd, or a -1 in case of error. In this particular case, 
> the "specific code path that leads to fd being -1" is when we can't get 
> a container fd for some reason. I believe this is a very remote 
> possibility as by the time we're spinning up the socket listening thread 
> we're pretty sure we have a working VFIO container, but this is a valid 
> fix nevertheless. Maybe having it >= 0 (or > 0, to be precise) would be 
> cleaner, but it really makes no difference here.

The point of my suggestion is that it would catch *any* negative value 
for fd as opposed to just -1.

I agree 0 should never happen since it is stdin but it is technically a 
valid fd that could occur if the user program did close(STDIN_FILENO) 
for some reason.

I don't feel too strongly about it but feel like if we are going to fix 
what amounts to close() possibly returning EBADF we might as well fix it 
for all cases.

Thanks,
Patrick
Kuba Kozak Sept. 21, 2017, 9:49 a.m. UTC | #5 
Hi,

Referring to Patrick suggestion I'll prepare patch with  (fd >= 0) condition.

Thanks,
Kuba

> -----Original Message-----

> From: Patrick MacArthur [mailto:patrick@patrickmacarthur.net]

> Sent: Thursday, September 21, 2017 04:28

> To: Burakov, Anatoly <anatoly.burakov@intel.com>; Kozak, KubaX <kubax.kozak@intel.com>

> Cc: dev@dpdk.org; stable@dpdk.org

> Subject: Re: [PATCH] vfio: fix close unchecked file descriptor

> 

> On 09/20/2017 10:39 AM, Burakov, Anatoly wrote:

> > On 20-Sep-17 3:34 PM, Patrick MacArthur wrote:

> >> On 09/20/2017 05:59 AM, Kuba Kozak wrote:

> >>> Add file descriptor value check before calling close() function.

> >>>

> >>> Coverity issue: 141297

> >>> Fixes: 811b6b25060f ("vfio: fix file descriptor leak in

> >>> multi-process")

> >>> Cc: patrick@patrickmacarthur.net

> >>> Cc: stable@dpdk.org

> >>>

> >>> Signed-off-by: Kuba Kozak <kubax.kozak@intel.com>

> >>> ---

> >>>   lib/librte_eal/linuxapp/eal/eal_vfio_mp_sync.c | 3 ++-

> >>>   1 file changed, 2 insertions(+), 1 deletion(-)

> >>>

> >>> diff --git a/lib/librte_eal/linuxapp/eal/eal_vfio_mp_sync.c

> >>> b/lib/librte_eal/linuxapp/eal/eal_vfio_mp_sync.c

> >>> index 7e8095c..c04f548 100644

> >>> --- a/lib/librte_eal/linuxapp/eal/eal_vfio_mp_sync.c

> >>> +++ b/lib/librte_eal/linuxapp/eal/eal_vfio_mp_sync.c

> >>> @@ -301,7 +301,8 @@ vfio_mp_sync_thread(void __rte_unused * arg)

> >>>                   vfio_mp_sync_send_request(conn_sock, SOCKET_ERR);

> >>>               else

> >>>                   vfio_mp_sync_send_fd(conn_sock, fd);

> >>> -            close(fd);

> >>> +            if (fd != -1)

> >>> +                close(fd);

> >>

> >> IMHO this should be:

> >>

> >>          if (fd >= 0)

> >>

> >> What specifically is Coverity complaining about here? Is there a

> >> specific code path that leads to fd being -1 here?

> >>

> > Hi Patrick,

> >

> > There's no way the fd will be 0 - the function we get the value from

> > returns a valid fd, or a -1 in case of error. In this particular case,

> > the "specific code path that leads to fd being -1" is when we can't

> > get a container fd for some reason. I believe this is a very remote

> > possibility as by the time we're spinning up the socket listening

> > thread we're pretty sure we have a working VFIO container, but this is

> > a valid fix nevertheless. Maybe having it >= 0 (or > 0, to be precise)

> > would be cleaner, but it really makes no difference here.

> 

> The point of my suggestion is that it would catch *any* negative value for fd as opposed to just -1.

> 

> I agree 0 should never happen since it is stdin but it is technically a valid fd that could occur if the user

> program did close(STDIN_FILENO) for some reason.

> 

> I don't feel too strongly about it but feel like if we are going to fix what amounts to close() possibly

> returning EBADF we might as well fix it for all cases.

> 

> Thanks,

> Patrick
diff mbox

Patch

diff --git a/lib/librte_eal/linuxapp/eal/eal_vfio_mp_sync.c b/lib/librte_eal/linuxapp/eal/eal_vfio_mp_sync.c
index 7e8095c..c04f548 100644
--- a/lib/librte_eal/linuxapp/eal/eal_vfio_mp_sync.c
+++ b/lib/librte_eal/linuxapp/eal/eal_vfio_mp_sync.c
@@ -301,7 +301,8 @@  vfio_mp_sync_thread(void __rte_unused * arg)
 				vfio_mp_sync_send_request(conn_sock, SOCKET_ERR);
 			else
 				vfio_mp_sync_send_fd(conn_sock, fd);
-			close(fd);
+			if (fd != -1)
+				close(fd);
 			break;
 		case SOCKET_REQ_GROUP:
 			/* wait for group number */