diff mbox

[dpdk-dev,v4,16/18] app/proc-info: sprintf overrun bug

Message ID 152600319626.53146.13225564187658388686.stgit@localhost.localdomain (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State Superseded, archived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

Andy Green May 11, 2018, 1:46 a.m. UTC 
  /home/agreen/projects/dpdk/app/proc-info/main.c: In function
‘nic_xstats_display’:
/home/agreen/projects/dpdk/app/proc-info/main.c:495:45:
error: ‘%s’ directive writing up to 255 bytes into a region
of size between 165 and 232 [-Werror=format-overflow=]
    sprintf(buf, "PUTVAL %s/dpdkstat-port.%u/%s-%s N:%"
                                             ^~
     PRIu64"\n", host_id, port_id, counter_type,
                                   ~~~~~~~~~~~~
/home/agreen/projects/dpdk/app/proc-info/main.c:495:4: note:
‘sprintf’ output between 31 and 435 bytes into a destination
of size 256
    sprintf(buf, "PUTVAL %s/dpdkstat-port.%u/%s-%s N:%"
    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     PRIu64"\n", host_id, port_id, counter_type,
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     xstats_names[i].name, values[i]);

Signed-off-by: Andy Green <andy@warmcat.com>
---
 app/proc-info/main.c |    9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

Comments

De Lara Guarch, Pablo May 11, 2018, 12:26 p.m. UTC | #1 
> -----Original Message-----

> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Andy Green

> Sent: Friday, May 11, 2018 2:47 AM

> To: dev@dpdk.org

> Subject: [dpdk-dev] [PATCH v4 16/18] app/proc-info: sprintf overrun bug

> 

> /home/agreen/projects/dpdk/app/proc-info/main.c: In function

> ‘nic_xstats_display’:

> /home/agreen/projects/dpdk/app/proc-info/main.c:495:45:

> error: ‘%s’ directive writing up to 255 bytes into a region of size between 165

> and 232 [-Werror=format-overflow=]

>     sprintf(buf, "PUTVAL %s/dpdkstat-port.%u/%s-%s N:%"

>                                              ^~

>      PRIu64"\n", host_id, port_id, counter_type,

>                                    ~~~~~~~~~~~~

> /home/agreen/projects/dpdk/app/proc-info/main.c:495:4: note:

> ‘sprintf’ output between 31 and 435 bytes into a destination of size 256

>     sprintf(buf, "PUTVAL %s/dpdkstat-port.%u/%s-%s N:%"

>     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

>      PRIu64"\n", host_id, port_id, counter_type,

>      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

>      xstats_names[i].name, values[i]);

> 

> Signed-off-by: Andy Green <andy@warmcat.com>

> ---

>  app/proc-info/main.c |    9 +++++++--

>  1 file changed, 7 insertions(+), 2 deletions(-)

> 

> diff --git a/app/proc-info/main.c b/app/proc-info/main.c index

> 539e13243..df46c235e 100644

> --- a/app/proc-info/main.c

> +++ b/app/proc-info/main.c

> @@ -488,14 +488,19 @@ nic_xstats_display(uint16_t port_id)

>  		if (enable_collectd_format) {

>  			char counter_type[MAX_STRING_LEN];

>  			char buf[MAX_STRING_LEN];

> +			size_t n;

> 

>  			collectd_resolve_cnt_type(counter_type,

>  						  sizeof(counter_type),

>  						  xstats_names[i].name);

> -			sprintf(buf, "PUTVAL %s/dpdkstat-port.%u/%s-%s N:%"

> +			n = snprintf(buf, MAX_STRING_LEN,

> +				"PUTVAL %s/dpdkstat-port.%u/%s-%s N:%"

>  				PRIu64"\n", host_id, port_id, counter_type,

>  				xstats_names[i].name, values[i]);

> -			ret = write(stdout_fd, buf, strlen(buf));

> +			buf[sizeof(buf) - 1] = '\0';


No need to NULL terminate, since snprintf already does it.

> +			if (n > sizeof(buf) - 1)

> +				n = sizeof(buf) - 1;


If (n > sizeof(buf) -1 ), it means that there wasn't enough space to write all the data,
So shouldn't we return an error here?

> +			ret = write(stdout_fd, buf, n);

>  			if (ret < 0)

>  				goto err;

>  		} else {


Missing fixes line and CC stable.

Fixes: 2deb6b5246d7 ("app/procinfo: add collectd format and host id")
Cc: stable@dpdk.org
Andy Green May 12, 2018, 1:33 a.m. UTC | #2 
On 05/11/2018 08:26 PM, De Lara Guarch, Pablo wrote:
> 
> 
>> -----Original Message-----
>> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Andy Green
>> Sent: Friday, May 11, 2018 2:47 AM
>> To: dev@dpdk.org
>> Subject: [dpdk-dev] [PATCH v4 16/18] app/proc-info: sprintf overrun bug
>>
>> /home/agreen/projects/dpdk/app/proc-info/main.c: In function
>> ‘nic_xstats_display’:
>> /home/agreen/projects/dpdk/app/proc-info/main.c:495:45:
>> error: ‘%s’ directive writing up to 255 bytes into a region of size between 165
>> and 232 [-Werror=format-overflow=]
>>      sprintf(buf, "PUTVAL %s/dpdkstat-port.%u/%s-%s N:%"
>>                                               ^~
>>       PRIu64"\n", host_id, port_id, counter_type,
>>                                     ~~~~~~~~~~~~
>> /home/agreen/projects/dpdk/app/proc-info/main.c:495:4: note:
>> ‘sprintf’ output between 31 and 435 bytes into a destination of size 256
>>      sprintf(buf, "PUTVAL %s/dpdkstat-port.%u/%s-%s N:%"
>>      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>       PRIu64"\n", host_id, port_id, counter_type,
>>       ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>       xstats_names[i].name, values[i]);
>>
>> Signed-off-by: Andy Green <andy@warmcat.com>
>> ---
>>   app/proc-info/main.c |    9 +++++++--
>>   1 file changed, 7 insertions(+), 2 deletions(-)
>>
>> diff --git a/app/proc-info/main.c b/app/proc-info/main.c index
>> 539e13243..df46c235e 100644
>> --- a/app/proc-info/main.c
>> +++ b/app/proc-info/main.c
>> @@ -488,14 +488,19 @@ nic_xstats_display(uint16_t port_id)
>>   		if (enable_collectd_format) {
>>   			char counter_type[MAX_STRING_LEN];
>>   			char buf[MAX_STRING_LEN];
>> +			size_t n;
>>
>>   			collectd_resolve_cnt_type(counter_type,
>>   						  sizeof(counter_type),
>>   						  xstats_names[i].name);
>> -			sprintf(buf, "PUTVAL %s/dpdkstat-port.%u/%s-%s N:%"
>> +			n = snprintf(buf, MAX_STRING_LEN,
>> +				"PUTVAL %s/dpdkstat-port.%u/%s-%s N:%"
>>   				PRIu64"\n", host_id, port_id, counter_type,
>>   				xstats_names[i].name, values[i]);
>> -			ret = write(stdout_fd, buf, strlen(buf));
>> +			buf[sizeof(buf) - 1] = '\0';
> 
> No need to NULL terminate, since snprintf already does it.

OK.

>> +			if (n > sizeof(buf) - 1)
>> +				n = sizeof(buf) - 1;
> 
> If (n > sizeof(buf) -1 ), it means that there wasn't enough space to write all the data,
> So shouldn't we return an error here?

It's just logging stuff, policy about truncated overlength logs could go 
either way.

Prior to this patch its policy was to corrupt your stack if overlength 
;-) so I think it's moving it on in the right direction merely 
truncating it.

-Andy

>> +			ret = write(stdout_fd, buf, n);
>>   			if (ret < 0)
>>   				goto err;
>>   		} else {
> 
> Missing fixes line and CC stable.
> 
> Fixes: 2deb6b5246d7 ("app/procinfo: add collectd format and host id")
> Cc: stable@dpdk.org
>
diff mbox

Patch

diff --git a/app/proc-info/main.c b/app/proc-info/main.c
index 539e13243..df46c235e 100644
--- a/app/proc-info/main.c
+++ b/app/proc-info/main.c
@@ -488,14 +488,19 @@  nic_xstats_display(uint16_t port_id)
 		if (enable_collectd_format) {
 			char counter_type[MAX_STRING_LEN];
 			char buf[MAX_STRING_LEN];
+			size_t n;
 
 			collectd_resolve_cnt_type(counter_type,
 						  sizeof(counter_type),
 						  xstats_names[i].name);
-			sprintf(buf, "PUTVAL %s/dpdkstat-port.%u/%s-%s N:%"
+			n = snprintf(buf, MAX_STRING_LEN,
+				"PUTVAL %s/dpdkstat-port.%u/%s-%s N:%"
 				PRIu64"\n", host_id, port_id, counter_type,
 				xstats_names[i].name, values[i]);
-			ret = write(stdout_fd, buf, strlen(buf));
+			buf[sizeof(buf) - 1] = '\0';
+			if (n > sizeof(buf) - 1)
+				n = sizeof(buf) - 1;
+			ret = write(stdout_fd, buf, n);
 			if (ret < 0)
 				goto err;
 		} else {