diff mbox series

test/eventdev: fix sprintf with snprintf

Message ID 1549449822-412-1-git-send-email-pallantlax.poornima@intel.com (mailing list archive)
State Accepted, archived
Delegated to: Jerin Jacob
Headers
Series test/eventdev: fix sprintf with snprintf |

Checks

Context Check Description
ci/checkpatch success coding style OK
ci/mellanox-Performance-Testing success Performance Testing PASS
ci/intel-Performance-Testing success Performance Testing PASS
ci/Intel-compilation success Compilation OK

Commit Message

Poornima, PallantlaX Feb. 6, 2019, 10:43 a.m. UTC 
  sprintf function is not secure as it doesn't check the length of string.
More secure function snprintf is used.

Fixes: 2a9c83ae3b ("test/eventdev: add multi-ports test")
Cc: stable@dpdk.org

Signed-off-by: Pallantla Poornima <pallantlax.poornima@intel.com>
---
 test/test/test_event_eth_rx_adapter.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Comments

Aaron Conole Feb. 8, 2019, 9:19 p.m. UTC | #1 
Pallantla Poornima <pallantlax.poornima@intel.com> writes:

> sprintf function is not secure as it doesn't check the length of string.
> More secure function snprintf is used.
>
> Fixes: 2a9c83ae3b ("test/eventdev: add multi-ports test")
> Cc: stable@dpdk.org
>
> Signed-off-by: Pallantla Poornima <pallantlax.poornima@intel.com>
> ---
>  test/test/test_event_eth_rx_adapter.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/test/test/test_event_eth_rx_adapter.c b/test/test/test_event_eth_rx_adapter.c
> index 1d3be82b5..38f5c039f 100644
> --- a/test/test/test_event_eth_rx_adapter.c
> +++ b/test/test/test_event_eth_rx_adapter.c
> @@ -479,7 +479,8 @@ adapter_multi_eth_add_del(void)
>  	/* add the max port for rx_adapter */
>  	port_index = rte_eth_dev_count_total();
>  	for (; port_index < RTE_MAX_ETHPORTS; port_index += 1) {
> -		sprintf(driver_name, "%s%u", "net_null", drv_id);
> +		snprintf(driver_name, sizeof(driver_name), "%s%u", "net_null",
> +				drv_id);
>  		err = rte_vdev_init(driver_name, NULL);
>  		TEST_ASSERT(err == 0, "Failed driver %s got %d",
>  		driver_name, err);

You call this a fix, but it's not possible for the value of drv_id to
exceed '32' and the buffer size is plenty accommodating for that.  Did I
miss something?  What is this fixing?
Jananee Parthasarathy March 12, 2019, 7:41 a.m. UTC | #2 
Hi

>-----Original Message-----
>From: Parthasarathy, JananeeX M
>Sent: Tuesday, February 19, 2019 6:33 PM
>To: Aaron Conole <aconole@redhat.com>; Poornima, PallantlaX
><pallantlax.poornima@intel.com>
>Cc: dev@dpdk.org; Pattan, Reshma <reshma.pattan@intel.com>; Rao, Nikhil
><nikhil.rao@intel.com>; stable@dpdk.org
>Subject: RE: [dpdk-dev] [PATCH] test/eventdev: fix sprintf with snprintf
>
>
>
>>-----Original Message-----
>>From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Aaron Conole
>>Sent: Saturday, February 09, 2019 2:50 AM
>>To: Poornima, PallantlaX <pallantlax.poornima@intel.com>
>>Cc: dev@dpdk.org; Pattan, Reshma <reshma.pattan@intel.com>; Rao, Nikhil
>><nikhil.rao@intel.com>; stable@dpdk.org
>>Subject: Re: [dpdk-dev] [PATCH] test/eventdev: fix sprintf with
>>snprintf
>>
>>Pallantla Poornima <pallantlax.poornima@intel.com> writes:
>>
>>> sprintf function is not secure as it doesn't check the length of string.
>>> More secure function snprintf is used.
>>>
>>> Fixes: 2a9c83ae3b ("test/eventdev: add multi-ports test")
>>> Cc: stable@dpdk.org
>>>
>>> Signed-off-by: Pallantla Poornima <pallantlax.poornima@intel.com>
>>> ---
>>>  test/test/test_event_eth_rx_adapter.c | 3 ++-
>>>  1 file changed, 2 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/test/test/test_event_eth_rx_adapter.c
>>> b/test/test/test_event_eth_rx_adapter.c
>>> index 1d3be82b5..38f5c039f 100644
>>> --- a/test/test/test_event_eth_rx_adapter.c
>>> +++ b/test/test/test_event_eth_rx_adapter.c
>>> @@ -479,7 +479,8 @@ adapter_multi_eth_add_del(void)
>>>  	/* add the max port for rx_adapter */
>>>  	port_index = rte_eth_dev_count_total();
>>>  	for (; port_index < RTE_MAX_ETHPORTS; port_index += 1) {
>>> -		sprintf(driver_name, "%s%u", "net_null", drv_id);
>>> +		snprintf(driver_name, sizeof(driver_name), "%s%u", "net_null",
>>> +				drv_id);
>>>  		err = rte_vdev_init(driver_name, NULL);
>>>  		TEST_ASSERT(err == 0, "Failed driver %s got %d",
>>>  		driver_name, err);
>>
>>You call this a fix, but it's not possible for the value of drv_id to
>>exceed '32' and the buffer size is plenty accommodating for that.  Did
>>I miss something?  What is this fixing?
>
>It is better practice to use snprintf although in this case buffer will not overflow
>as size is big enough to accommodate. The changes were done mainly to
>replace sprintf to snprintf. Probably we can remove "fix" line as it is not issue in
>this scenario.
>
>Thanks
>M.P.Jananee

Please suggest if we can remove "fix" line.

Thanks
Aaron Conole March 12, 2019, 2:44 p.m. UTC | #3 
"Parthasarathy, JananeeX M" <jananeex.m.parthasarathy@intel.com> writes:

> Hi
>
>>-----Original Message-----
>>From: Parthasarathy, JananeeX M
>>Sent: Tuesday, February 19, 2019 6:33 PM
>>To: Aaron Conole <aconole@redhat.com>; Poornima, PallantlaX
>><pallantlax.poornima@intel.com>
>>Cc: dev@dpdk.org; Pattan, Reshma <reshma.pattan@intel.com>; Rao, Nikhil
>><nikhil.rao@intel.com>; stable@dpdk.org
>>Subject: RE: [dpdk-dev] [PATCH] test/eventdev: fix sprintf with snprintf
>>
>>
>>
>>>-----Original Message-----
>>>From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Aaron Conole
>>>Sent: Saturday, February 09, 2019 2:50 AM
>>>To: Poornima, PallantlaX <pallantlax.poornima@intel.com>
>>>Cc: dev@dpdk.org; Pattan, Reshma <reshma.pattan@intel.com>; Rao, Nikhil
>>><nikhil.rao@intel.com>; stable@dpdk.org
>>>Subject: Re: [dpdk-dev] [PATCH] test/eventdev: fix sprintf with
>>>snprintf
>>>
>>>Pallantla Poornima <pallantlax.poornima@intel.com> writes:
>>>
>>>> sprintf function is not secure as it doesn't check the length of string.
>>>> More secure function snprintf is used.
>>>>
>>>> Fixes: 2a9c83ae3b ("test/eventdev: add multi-ports test")
>>>> Cc: stable@dpdk.org
>>>>
>>>> Signed-off-by: Pallantla Poornima <pallantlax.poornima@intel.com>
>>>> ---
>>>>  test/test/test_event_eth_rx_adapter.c | 3 ++-
>>>>  1 file changed, 2 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/test/test/test_event_eth_rx_adapter.c
>>>> b/test/test/test_event_eth_rx_adapter.c
>>>> index 1d3be82b5..38f5c039f 100644
>>>> --- a/test/test/test_event_eth_rx_adapter.c
>>>> +++ b/test/test/test_event_eth_rx_adapter.c
>>>> @@ -479,7 +479,8 @@ adapter_multi_eth_add_del(void)
>>>>  	/* add the max port for rx_adapter */
>>>>  	port_index = rte_eth_dev_count_total();
>>>>  	for (; port_index < RTE_MAX_ETHPORTS; port_index += 1) {
>>>> -		sprintf(driver_name, "%s%u", "net_null", drv_id);
>>>> +		snprintf(driver_name, sizeof(driver_name), "%s%u", "net_null",
>>>> +				drv_id);
>>>>  		err = rte_vdev_init(driver_name, NULL);
>>>>  		TEST_ASSERT(err == 0, "Failed driver %s got %d",
>>>>  		driver_name, err);
>>>
>>>You call this a fix, but it's not possible for the value of drv_id to
>>>exceed '32' and the buffer size is plenty accommodating for that.  Did
>>>I miss something?  What is this fixing?
>>
>>It is better practice to use snprintf although in this case buffer will not overflow
>>as size is big enough to accommodate. The changes were done mainly to
>>replace sprintf to snprintf. Probably we can remove "fix" line as it is not issue in
>>this scenario.
>>
>>Thanks
>>M.P.Jananee
>
> Please suggest if we can remove "fix" line.

This is a stylistic change, I don't think it's appropriate to call it a
fix, so I think you can remove the "Fixes" line.

On further reflection, I actually think it will still be wrong.  If the
size buffer is ever changed, what will happen on truncation?  We don't
get an overflow any longer, but we still pass an invalid argument, so I
don't think this 'fix' is really even a fix.  It still has a bug -
albeit not one that immediately triggers SSP exception or stack
overflow.

Makes sense?

> Thanks
Ferruh Yigit March 13, 2019, 11:04 a.m. UTC | #4 
On 3/12/2019 2:44 PM, Aaron Conole wrote:
> "Parthasarathy, JananeeX M" <jananeex.m.parthasarathy@intel.com> writes:
> 
>> Hi
>>
>>> -----Original Message-----
>>> From: Parthasarathy, JananeeX M
>>> Sent: Tuesday, February 19, 2019 6:33 PM
>>> To: Aaron Conole <aconole@redhat.com>; Poornima, PallantlaX
>>> <pallantlax.poornima@intel.com>
>>> Cc: dev@dpdk.org; Pattan, Reshma <reshma.pattan@intel.com>; Rao, Nikhil
>>> <nikhil.rao@intel.com>; stable@dpdk.org
>>> Subject: RE: [dpdk-dev] [PATCH] test/eventdev: fix sprintf with snprintf
>>>
>>>
>>>
>>>> -----Original Message-----
>>>> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Aaron Conole
>>>> Sent: Saturday, February 09, 2019 2:50 AM
>>>> To: Poornima, PallantlaX <pallantlax.poornima@intel.com>
>>>> Cc: dev@dpdk.org; Pattan, Reshma <reshma.pattan@intel.com>; Rao, Nikhil
>>>> <nikhil.rao@intel.com>; stable@dpdk.org
>>>> Subject: Re: [dpdk-dev] [PATCH] test/eventdev: fix sprintf with
>>>> snprintf
>>>>
>>>> Pallantla Poornima <pallantlax.poornima@intel.com> writes:
>>>>
>>>>> sprintf function is not secure as it doesn't check the length of string.
>>>>> More secure function snprintf is used.
>>>>>
>>>>> Fixes: 2a9c83ae3b ("test/eventdev: add multi-ports test")
>>>>> Cc: stable@dpdk.org
>>>>>
>>>>> Signed-off-by: Pallantla Poornima <pallantlax.poornima@intel.com>
>>>>> ---
>>>>>  test/test/test_event_eth_rx_adapter.c | 3 ++-
>>>>>  1 file changed, 2 insertions(+), 1 deletion(-)
>>>>>
>>>>> diff --git a/test/test/test_event_eth_rx_adapter.c
>>>>> b/test/test/test_event_eth_rx_adapter.c
>>>>> index 1d3be82b5..38f5c039f 100644
>>>>> --- a/test/test/test_event_eth_rx_adapter.c
>>>>> +++ b/test/test/test_event_eth_rx_adapter.c
>>>>> @@ -479,7 +479,8 @@ adapter_multi_eth_add_del(void)
>>>>>  	/* add the max port for rx_adapter */
>>>>>  	port_index = rte_eth_dev_count_total();
>>>>>  	for (; port_index < RTE_MAX_ETHPORTS; port_index += 1) {
>>>>> -		sprintf(driver_name, "%s%u", "net_null", drv_id);
>>>>> +		snprintf(driver_name, sizeof(driver_name), "%s%u", "net_null",
>>>>> +				drv_id);
>>>>>  		err = rte_vdev_init(driver_name, NULL);
>>>>>  		TEST_ASSERT(err == 0, "Failed driver %s got %d",
>>>>>  		driver_name, err);
>>>>
>>>> You call this a fix, but it's not possible for the value of drv_id to
>>>> exceed '32' and the buffer size is plenty accommodating for that.  Did
>>>> I miss something?  What is this fixing?
>>>
>>> It is better practice to use snprintf although in this case buffer will not overflow
>>> as size is big enough to accommodate. The changes were done mainly to
>>> replace sprintf to snprintf. Probably we can remove "fix" line as it is not issue in
>>> this scenario.
>>>
>>> Thanks
>>> M.P.Jananee
>>
>> Please suggest if we can remove "fix" line.
> 
> This is a stylistic change, I don't think it's appropriate to call it a
> fix, so I think you can remove the "Fixes" line.
> 
> On further reflection, I actually think it will still be wrong.  If the
> size buffer is ever changed, what will happen on truncation?  We don't
> get an overflow any longer, but we still pass an invalid argument, so I
> don't think this 'fix' is really even a fix.  It still has a bug -
> albeit not one that immediately triggers SSP exception or stack
> overflow.
> 
> Makes sense?

Hi Aaron,

I see your point and I agree that existing code is not broken, it is functioning
well as it is.

But we are fixing a possible issue, or lets say fixing using less secure API
although it doesn't cause any problem right now. Perhaps we can update the patch
title slightly [1] but I am for keeping the fix and I think it makes sense to
keep "Fixes" tag so that this update can be backported to stable trees.

Thanks,
ferruh

[1]
test/eventdev: fix possible buffer overflow
Aaron Conole March 13, 2019, 1:43 p.m. UTC | #5 
Ferruh Yigit <ferruh.yigit@intel.com> writes:

> On 3/12/2019 2:44 PM, Aaron Conole wrote:
>> "Parthasarathy, JananeeX M" <jananeex.m.parthasarathy@intel.com> writes:
>> 
>>> Hi
>>>
>>>> -----Original Message-----
>>>> From: Parthasarathy, JananeeX M
>>>> Sent: Tuesday, February 19, 2019 6:33 PM
>>>> To: Aaron Conole <aconole@redhat.com>; Poornima, PallantlaX
>>>> <pallantlax.poornima@intel.com>
>>>> Cc: dev@dpdk.org; Pattan, Reshma <reshma.pattan@intel.com>; Rao, Nikhil
>>>> <nikhil.rao@intel.com>; stable@dpdk.org
>>>> Subject: RE: [dpdk-dev] [PATCH] test/eventdev: fix sprintf with snprintf
>>>>
>>>>
>>>>
>>>>> -----Original Message-----
>>>>> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Aaron Conole
>>>>> Sent: Saturday, February 09, 2019 2:50 AM
>>>>> To: Poornima, PallantlaX <pallantlax.poornima@intel.com>
>>>>> Cc: dev@dpdk.org; Pattan, Reshma <reshma.pattan@intel.com>; Rao, Nikhil
>>>>> <nikhil.rao@intel.com>; stable@dpdk.org
>>>>> Subject: Re: [dpdk-dev] [PATCH] test/eventdev: fix sprintf with
>>>>> snprintf
>>>>>
>>>>> Pallantla Poornima <pallantlax.poornima@intel.com> writes:
>>>>>
>>>>>> sprintf function is not secure as it doesn't check the length of string.
>>>>>> More secure function snprintf is used.
>>>>>>
>>>>>> Fixes: 2a9c83ae3b ("test/eventdev: add multi-ports test")
>>>>>> Cc: stable@dpdk.org
>>>>>>
>>>>>> Signed-off-by: Pallantla Poornima <pallantlax.poornima@intel.com>
>>>>>> ---
>>>>>>  test/test/test_event_eth_rx_adapter.c | 3 ++-
>>>>>>  1 file changed, 2 insertions(+), 1 deletion(-)
>>>>>>
>>>>>> diff --git a/test/test/test_event_eth_rx_adapter.c
>>>>>> b/test/test/test_event_eth_rx_adapter.c
>>>>>> index 1d3be82b5..38f5c039f 100644
>>>>>> --- a/test/test/test_event_eth_rx_adapter.c
>>>>>> +++ b/test/test/test_event_eth_rx_adapter.c
>>>>>> @@ -479,7 +479,8 @@ adapter_multi_eth_add_del(void)
>>>>>>  	/* add the max port for rx_adapter */
>>>>>>  	port_index = rte_eth_dev_count_total();
>>>>>>  	for (; port_index < RTE_MAX_ETHPORTS; port_index += 1) {
>>>>>> -		sprintf(driver_name, "%s%u", "net_null", drv_id);
>>>>>> +		snprintf(driver_name, sizeof(driver_name), "%s%u", "net_null",
>>>>>> +				drv_id);
>>>>>>  		err = rte_vdev_init(driver_name, NULL);
>>>>>>  		TEST_ASSERT(err == 0, "Failed driver %s got %d",
>>>>>>  		driver_name, err);
>>>>>
>>>>> You call this a fix, but it's not possible for the value of drv_id to
>>>>> exceed '32' and the buffer size is plenty accommodating for that.  Did
>>>>> I miss something?  What is this fixing?
>>>>
>>>> It is better practice to use snprintf although in this case buffer will not overflow
>>>> as size is big enough to accommodate. The changes were done mainly to
>>>> replace sprintf to snprintf. Probably we can remove "fix" line as it is not issue in
>>>> this scenario.
>>>>
>>>> Thanks
>>>> M.P.Jananee
>>>
>>> Please suggest if we can remove "fix" line.
>> 
>> This is a stylistic change, I don't think it's appropriate to call it a
>> fix, so I think you can remove the "Fixes" line.
>> 
>> On further reflection, I actually think it will still be wrong.  If the
>> size buffer is ever changed, what will happen on truncation?  We don't
>> get an overflow any longer, but we still pass an invalid argument, so I
>> don't think this 'fix' is really even a fix.  It still has a bug -
>> albeit not one that immediately triggers SSP exception or stack
>> overflow.
>> 
>> Makes sense?
>
> Hi Aaron,
>
> I see your point and I agree that existing code is not broken, it is functioning
> well as it is.
>
> But we are fixing a possible issue, or lets say fixing using less secure API
> although it doesn't cause any problem right now. Perhaps we can update the patch
> title slightly [1] but I am for keeping the fix and I think it makes sense to
> keep "Fixes" tag so that this update can be backported to stable trees.

I can get behind changing the sprintf to snprintf, since it is a better
API - but it needs to handle the return value properly (otherwise, in
this case we will specify an incorrect device).  I can even
understanding calling it a fix, it's metadata and is probably needed
from some kind of compliance anyway.

I also understand that this is in test suite, but people usually copy
code from test suites and that means the flaw at some point will be
propagated.  So I still think it should be a version which checks the
return code.  Otherwise in production if this is copied, and if I can
figure out how to overflow the counter knowing the buffer boundaries,
then there is a fixed device that will always be chosen.

I think it goes for all the other 's/sprintf\(/snprintf\)' replacements,
too.  Maybe I misunderstand something?

> Thanks,
> ferruh
>
> [1]
> test/eventdev: fix possible buffer overflow
Ferruh Yigit March 13, 2019, 2:07 p.m. UTC | #6 
On 3/13/2019 1:43 PM, Aaron Conole wrote:
> Ferruh Yigit <ferruh.yigit@intel.com> writes:
> 
>> On 3/12/2019 2:44 PM, Aaron Conole wrote:
>>> "Parthasarathy, JananeeX M" <jananeex.m.parthasarathy@intel.com> writes:
>>>
>>>> Hi
>>>>
>>>>> -----Original Message-----
>>>>> From: Parthasarathy, JananeeX M
>>>>> Sent: Tuesday, February 19, 2019 6:33 PM
>>>>> To: Aaron Conole <aconole@redhat.com>; Poornima, PallantlaX
>>>>> <pallantlax.poornima@intel.com>
>>>>> Cc: dev@dpdk.org; Pattan, Reshma <reshma.pattan@intel.com>; Rao, Nikhil
>>>>> <nikhil.rao@intel.com>; stable@dpdk.org
>>>>> Subject: RE: [dpdk-dev] [PATCH] test/eventdev: fix sprintf with snprintf
>>>>>
>>>>>
>>>>>
>>>>>> -----Original Message-----
>>>>>> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Aaron Conole
>>>>>> Sent: Saturday, February 09, 2019 2:50 AM
>>>>>> To: Poornima, PallantlaX <pallantlax.poornima@intel.com>
>>>>>> Cc: dev@dpdk.org; Pattan, Reshma <reshma.pattan@intel.com>; Rao, Nikhil
>>>>>> <nikhil.rao@intel.com>; stable@dpdk.org
>>>>>> Subject: Re: [dpdk-dev] [PATCH] test/eventdev: fix sprintf with
>>>>>> snprintf
>>>>>>
>>>>>> Pallantla Poornima <pallantlax.poornima@intel.com> writes:
>>>>>>
>>>>>>> sprintf function is not secure as it doesn't check the length of string.
>>>>>>> More secure function snprintf is used.
>>>>>>>
>>>>>>> Fixes: 2a9c83ae3b ("test/eventdev: add multi-ports test")
>>>>>>> Cc: stable@dpdk.org
>>>>>>>
>>>>>>> Signed-off-by: Pallantla Poornima <pallantlax.poornima@intel.com>
>>>>>>> ---
>>>>>>>  test/test/test_event_eth_rx_adapter.c | 3 ++-
>>>>>>>  1 file changed, 2 insertions(+), 1 deletion(-)
>>>>>>>
>>>>>>> diff --git a/test/test/test_event_eth_rx_adapter.c
>>>>>>> b/test/test/test_event_eth_rx_adapter.c
>>>>>>> index 1d3be82b5..38f5c039f 100644
>>>>>>> --- a/test/test/test_event_eth_rx_adapter.c
>>>>>>> +++ b/test/test/test_event_eth_rx_adapter.c
>>>>>>> @@ -479,7 +479,8 @@ adapter_multi_eth_add_del(void)
>>>>>>>  	/* add the max port for rx_adapter */
>>>>>>>  	port_index = rte_eth_dev_count_total();
>>>>>>>  	for (; port_index < RTE_MAX_ETHPORTS; port_index += 1) {
>>>>>>> -		sprintf(driver_name, "%s%u", "net_null", drv_id);
>>>>>>> +		snprintf(driver_name, sizeof(driver_name), "%s%u", "net_null",
>>>>>>> +				drv_id);
>>>>>>>  		err = rte_vdev_init(driver_name, NULL);
>>>>>>>  		TEST_ASSERT(err == 0, "Failed driver %s got %d",
>>>>>>>  		driver_name, err);
>>>>>>
>>>>>> You call this a fix, but it's not possible for the value of drv_id to
>>>>>> exceed '32' and the buffer size is plenty accommodating for that.  Did
>>>>>> I miss something?  What is this fixing?
>>>>>
>>>>> It is better practice to use snprintf although in this case buffer will not overflow
>>>>> as size is big enough to accommodate. The changes were done mainly to
>>>>> replace sprintf to snprintf. Probably we can remove "fix" line as it is not issue in
>>>>> this scenario.
>>>>>
>>>>> Thanks
>>>>> M.P.Jananee
>>>>
>>>> Please suggest if we can remove "fix" line.
>>>
>>> This is a stylistic change, I don't think it's appropriate to call it a
>>> fix, so I think you can remove the "Fixes" line.
>>>
>>> On further reflection, I actually think it will still be wrong.  If the
>>> size buffer is ever changed, what will happen on truncation?  We don't
>>> get an overflow any longer, but we still pass an invalid argument, so I
>>> don't think this 'fix' is really even a fix.  It still has a bug -
>>> albeit not one that immediately triggers SSP exception or stack
>>> overflow.
>>>
>>> Makes sense?
>>
>> Hi Aaron,
>>
>> I see your point and I agree that existing code is not broken, it is functioning
>> well as it is.
>>
>> But we are fixing a possible issue, or lets say fixing using less secure API
>> although it doesn't cause any problem right now. Perhaps we can update the patch
>> title slightly [1] but I am for keeping the fix and I think it makes sense to
>> keep "Fixes" tag so that this update can be backported to stable trees.
> 
> I can get behind changing the sprintf to snprintf, since it is a better
> API - but it needs to handle the return value properly (otherwise, in
> this case we will specify an incorrect device).  I can even
> understanding calling it a fix, it's metadata and is probably needed
> from some kind of compliance anyway.
> 
> I also understand that this is in test suite, but people usually copy
> code from test suites and that means the flaw at some point will be
> propagated.  So I still think it should be a version which checks the
> return code.  Otherwise in production if this is copied, and if I can
> figure out how to overflow the counter knowing the buffer boundaries,
> then there is a fixed device that will always be chosen.
> 
> I think it goes for all the other 's/sprintf\(/snprintf\)' replacements,
> too.  Maybe I misunderstand something?

These patches focus on preventing possible buffer overflow, the impact of
possible truncation changes case by case I think, like for this case I don't see
much benefit of adding return value check.

For all cases I expect truncation trigger a functional error which should be
already handled properly, like in this case 'rte_vdev_init()' will fail in
second call if buffer is small.

There may be cases to check the return value, but that should be the case with
'sprintf' as well, changing API to 'snprintf' shouldn't require additional check
by default.
Aaron Conole March 13, 2019, 2:35 p.m. UTC | #7 
Ferruh Yigit <ferruh.yigit@intel.com> writes:

> On 3/13/2019 1:43 PM, Aaron Conole wrote:
>> Ferruh Yigit <ferruh.yigit@intel.com> writes:
>> 
>>> On 3/12/2019 2:44 PM, Aaron Conole wrote:
>>>> "Parthasarathy, JananeeX M" <jananeex.m.parthasarathy@intel.com> writes:
>>>>
>>>>> Hi
>>>>>
>>>>>> -----Original Message-----
>>>>>> From: Parthasarathy, JananeeX M
>>>>>> Sent: Tuesday, February 19, 2019 6:33 PM
>>>>>> To: Aaron Conole <aconole@redhat.com>; Poornima, PallantlaX
>>>>>> <pallantlax.poornima@intel.com>
>>>>>> Cc: dev@dpdk.org; Pattan, Reshma <reshma.pattan@intel.com>; Rao, Nikhil
>>>>>> <nikhil.rao@intel.com>; stable@dpdk.org
>>>>>> Subject: RE: [dpdk-dev] [PATCH] test/eventdev: fix sprintf with snprintf
>>>>>>
>>>>>>
>>>>>>
>>>>>>> -----Original Message-----
>>>>>>> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Aaron Conole
>>>>>>> Sent: Saturday, February 09, 2019 2:50 AM
>>>>>>> To: Poornima, PallantlaX <pallantlax.poornima@intel.com>
>>>>>>> Cc: dev@dpdk.org; Pattan, Reshma <reshma.pattan@intel.com>; Rao, Nikhil
>>>>>>> <nikhil.rao@intel.com>; stable@dpdk.org
>>>>>>> Subject: Re: [dpdk-dev] [PATCH] test/eventdev: fix sprintf with
>>>>>>> snprintf
>>>>>>>
>>>>>>> Pallantla Poornima <pallantlax.poornima@intel.com> writes:
>>>>>>>
>>>>>>>> sprintf function is not secure as it doesn't check the length of string.
>>>>>>>> More secure function snprintf is used.
>>>>>>>>
>>>>>>>> Fixes: 2a9c83ae3b ("test/eventdev: add multi-ports test")
>>>>>>>> Cc: stable@dpdk.org
>>>>>>>>
>>>>>>>> Signed-off-by: Pallantla Poornima <pallantlax.poornima@intel.com>
>>>>>>>> ---
>>>>>>>>  test/test/test_event_eth_rx_adapter.c | 3 ++-
>>>>>>>>  1 file changed, 2 insertions(+), 1 deletion(-)
>>>>>>>>
>>>>>>>> diff --git a/test/test/test_event_eth_rx_adapter.c
>>>>>>>> b/test/test/test_event_eth_rx_adapter.c
>>>>>>>> index 1d3be82b5..38f5c039f 100644
>>>>>>>> --- a/test/test/test_event_eth_rx_adapter.c
>>>>>>>> +++ b/test/test/test_event_eth_rx_adapter.c
>>>>>>>> @@ -479,7 +479,8 @@ adapter_multi_eth_add_del(void)
>>>>>>>>  	/* add the max port for rx_adapter */
>>>>>>>>  	port_index = rte_eth_dev_count_total();
>>>>>>>>  	for (; port_index < RTE_MAX_ETHPORTS; port_index += 1) {
>>>>>>>> -		sprintf(driver_name, "%s%u", "net_null", drv_id);
>>>>>>>> +		snprintf(driver_name, sizeof(driver_name), "%s%u", "net_null",
>>>>>>>> +				drv_id);
>>>>>>>>  		err = rte_vdev_init(driver_name, NULL);
>>>>>>>>  		TEST_ASSERT(err == 0, "Failed driver %s got %d",
>>>>>>>>  		driver_name, err);
>>>>>>>
>>>>>>> You call this a fix, but it's not possible for the value of drv_id to
>>>>>>> exceed '32' and the buffer size is plenty accommodating for that.  Did
>>>>>>> I miss something?  What is this fixing?
>>>>>>
>>>>>> It is better practice to use snprintf although in this case buffer will not overflow
>>>>>> as size is big enough to accommodate. The changes were done mainly to
>>>>>> replace sprintf to snprintf. Probably we can remove "fix" line as it is not issue in
>>>>>> this scenario.
>>>>>>
>>>>>> Thanks
>>>>>> M.P.Jananee
>>>>>
>>>>> Please suggest if we can remove "fix" line.
>>>>
>>>> This is a stylistic change, I don't think it's appropriate to call it a
>>>> fix, so I think you can remove the "Fixes" line.
>>>>
>>>> On further reflection, I actually think it will still be wrong.  If the
>>>> size buffer is ever changed, what will happen on truncation?  We don't
>>>> get an overflow any longer, but we still pass an invalid argument, so I
>>>> don't think this 'fix' is really even a fix.  It still has a bug -
>>>> albeit not one that immediately triggers SSP exception or stack
>>>> overflow.
>>>>
>>>> Makes sense?
>>>
>>> Hi Aaron,
>>>
>>> I see your point and I agree that existing code is not broken, it is functioning
>>> well as it is.
>>>
>>> But we are fixing a possible issue, or lets say fixing using less secure API
>>> although it doesn't cause any problem right now. Perhaps we can update the patch
>>> title slightly [1] but I am for keeping the fix and I think it makes sense to
>>> keep "Fixes" tag so that this update can be backported to stable trees.
>> 
>> I can get behind changing the sprintf to snprintf, since it is a better
>> API - but it needs to handle the return value properly (otherwise, in
>> this case we will specify an incorrect device).  I can even
>> understanding calling it a fix, it's metadata and is probably needed
>> from some kind of compliance anyway.
>> 
>> I also understand that this is in test suite, but people usually copy
>> code from test suites and that means the flaw at some point will be
>> propagated.  So I still think it should be a version which checks the
>> return code.  Otherwise in production if this is copied, and if I can
>> figure out how to overflow the counter knowing the buffer boundaries,
>> then there is a fixed device that will always be chosen.
>> 
>> I think it goes for all the other 's/sprintf\(/snprintf\)' replacements,
>> too.  Maybe I misunderstand something?
>
> These patches focus on preventing possible buffer overflow, the impact of
> possible truncation changes case by case I think, like for this case I don't see
> much benefit of adding return value check.
>
> For all cases I expect truncation trigger a functional error which should be
> already handled properly, like in this case 'rte_vdev_init()' will fail in
> second call if buffer is small.

And give the user a bad error ("I said net_null1038123825, not net_null10
- bug in dpdk!").

> There may be cases to check the return value, but that should be the case with
> 'sprintf' as well, changing API to 'snprintf' shouldn't require additional check
> by default.

I agree, that's true.  I think it's the right thing to do here, though.
Jerin Jacob Kollanukkaran March 30, 2019, 2:15 p.m. UTC | #8 
On Wed, 2019-03-13 at 10:35 -0400, Aaron Conole wrote:
> 
> > For all cases I expect truncation trigger a functional error which
> > should be
> > already handled properly, like in this case 'rte_vdev_init()' will
> > fail in
> > second call if buffer is small.
> 
> And give the user a bad error ("I said net_null1038123825, not
> net_null10
> - bug in dpdk!").
> 
> > There may be cases to check the return value, but that should be
> > the case with
> > 'sprintf' as well, changing API to 'snprintf' shouldn't require
> > additional check
> > by default.
> 
> I agree, that's true.  I think it's the right thing to do here,
> though.

Aaron,

Are you expecting next version of this patch? Or I can merge this
patch?
Aaron Conole April 1, 2019, 8:37 p.m. UTC | #9 
Jerin Jacob Kollanukkaran <jerinj@marvell.com> writes:

> On Wed, 2019-03-13 at 10:35 -0400, Aaron Conole wrote:
>> 
>> > For all cases I expect truncation trigger a functional error which
>> > should be
>> > already handled properly, like in this case 'rte_vdev_init()' will
>> > fail in
>> > second call if buffer is small.
>> 
>> And give the user a bad error ("I said net_null1038123825, not
>> net_null10
>> - bug in dpdk!").
>> 
>> > There may be cases to check the return value, but that should be
>> > the case with
>> > 'sprintf' as well, changing API to 'snprintf' shouldn't require
>> > additional check
>> > by default.
>> 
>> I agree, that's true.  I think it's the right thing to do here,
>> though.
>
> Aaron,
>
> Are you expecting next version of this patch? Or I can merge this
> patch?

Go ahead and merge.
Jerin Jacob Kollanukkaran April 2, 2019, 1:35 a.m. UTC | #10 
On Mon, 2019-04-01 at 16:37 -0400, Aaron Conole wrote:
> 
> Jerin Jacob Kollanukkaran <jerinj@marvell.com> writes:
> 
> > On Wed, 2019-03-13 at 10:35 -0400, Aaron Conole wrote:
> > > > For all cases I expect truncation trigger a functional error
> > > > which
> > > > should be
> > > > already handled properly, like in this case 'rte_vdev_init()'
> > > > will
> > > > fail in
> > > > second call if buffer is small.
> > > 
> > > And give the user a bad error ("I said net_null1038123825, not
> > > net_null10
> > > - bug in dpdk!").
> > > 
> > > > There may be cases to check the return value, but that should
> > > > be
> > > > the case with
> > > > 'sprintf' as well, changing API to 'snprintf' shouldn't require
> > > > additional check
> > > > by default.
> > > 
> > > I agree, that's true.  I think it's the right thing to do here,
> > > though.
> > 
> > Aaron,
> > 
> > Are you expecting next version of this patch? Or I can merge this
> > patch?
> 
> Go ahead and merge.


Applied to dpdk-next-eventdev/master. Thanks.
diff mbox series

Patch

diff --git a/test/test/test_event_eth_rx_adapter.c b/test/test/test_event_eth_rx_adapter.c
index 1d3be82b5..38f5c039f 100644
--- a/test/test/test_event_eth_rx_adapter.c
+++ b/test/test/test_event_eth_rx_adapter.c
@@ -479,7 +479,8 @@  adapter_multi_eth_add_del(void)
 	/* add the max port for rx_adapter */
 	port_index = rte_eth_dev_count_total();
 	for (; port_index < RTE_MAX_ETHPORTS; port_index += 1) {
-		sprintf(driver_name, "%s%u", "net_null", drv_id);
+		snprintf(driver_name, sizeof(driver_name), "%s%u", "net_null",
+				drv_id);
 		err = rte_vdev_init(driver_name, NULL);
 		TEST_ASSERT(err == 0, "Failed driver %s got %d",
 		driver_name, err);