2020-12-07 14:50:21

by Colin King

Subject: [PATCH][next] seg6: fix unintentional integer overflow on left shift

From: Colin Ian King <[email protected]>

Shifting the integer value 1 is evaluated using 32-bit arithmetic
and then used in an expression that expects a unsigned long value
leads to a potential integer overflow. Fix this by using the BIT
macro to perform the shift to avoid the overflow.

Addresses-Coverity: ("Uninitentional integer overflow")
Fixes: 964adce526a4 ("seg6: improve management of behavior attributes")
Signed-off-by: Colin Ian King <[email protected]>
---
net/ipv6/seg6_local.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/ipv6/seg6_local.c b/net/ipv6/seg6_local.c
index b07f7c1c82a4..d68de8cd1207 100644
--- a/net/ipv6/seg6_local.c
+++ b/net/ipv6/seg6_local.c
@@ -1366,7 +1366,7 @@ static void __destroy_attrs(unsigned long parsed_attrs, int max_parsed,
* attribute; otherwise, we call the destroy() callback.
*/
for (i = 0; i < max_parsed; ++i) {
- if (!(parsed_attrs & (1 << i)))
+ if (!(parsed_attrs & BIT(i)))
continue;

param = &seg6_action_params[i];
--
2.29.2

2020-12-07 20:06:02

by Andrea Mayer

Subject: Re: [PATCH][next] seg6: fix unintentional integer overflow on left shift

On Mon, 7 Dec 2020 14:45:03 +0000
Colin King <[email protected]> wrote:

> From: Colin Ian King <[email protected]>
>
> Shifting the integer value 1 is evaluated using 32-bit arithmetic
> and then used in an expression that expects a unsigned long value
> leads to a potential integer overflow. Fix this by using the BIT
> macro to perform the shift to avoid the overflow.
>
> Addresses-Coverity: ("Uninitentional integer overflow")
> Fixes: 964adce526a4 ("seg6: improve management of behavior attributes")
> Signed-off-by: Colin Ian King <[email protected]>
> ---
> net/ipv6/seg6_local.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/net/ipv6/seg6_local.c b/net/ipv6/seg6_local.c
> index b07f7c1c82a4..d68de8cd1207 100644
> --- a/net/ipv6/seg6_local.c
> +++ b/net/ipv6/seg6_local.c
> @@ -1366,7 +1366,7 @@ static void __destroy_attrs(unsigned long parsed_attrs, int max_parsed,
> * attribute; otherwise, we call the destroy() callback.
> */
> for (i = 0; i < max_parsed; ++i) {
> - if (!(parsed_attrs & (1 << i)))
> + if (!(parsed_attrs & BIT(i)))
> continue;
>
> param = &seg6_action_params[i];
> --
> 2.29.2
>

Hi Colin,
thanks for the fix. I've just given a look a the whole seg6_local.c code and I
found that such issues is present in other parts of the code.

If we agree, I can make a fix which explicitly eliminates the several (1 << i)
in favor of BIT(i).

Andrea

2020-12-07 20:49:05

by Colin King

Subject: Re: [PATCH][next] seg6: fix unintentional integer overflow on left shift

On 07/12/2020 19:59, Andrea Mayer wrote:
> On Mon, 7 Dec 2020 14:45:03 +0000
> Colin King <[email protected]> wrote:
>
>> From: Colin Ian King <[email protected]>
>>
>> Shifting the integer value 1 is evaluated using 32-bit arithmetic
>> and then used in an expression that expects a unsigned long value
>> leads to a potential integer overflow. Fix this by using the BIT
>> macro to perform the shift to avoid the overflow.
>>
>> Addresses-Coverity: ("Uninitentional integer overflow")
>> Fixes: 964adce526a4 ("seg6: improve management of behavior attributes")
>> Signed-off-by: Colin Ian King <[email protected]>
>> ---
>> net/ipv6/seg6_local.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/net/ipv6/seg6_local.c b/net/ipv6/seg6_local.c
>> index b07f7c1c82a4..d68de8cd1207 100644
>> --- a/net/ipv6/seg6_local.c
>> +++ b/net/ipv6/seg6_local.c
>> @@ -1366,7 +1366,7 @@ static void __destroy_attrs(unsigned long parsed_attrs, int max_parsed,
>> * attribute; otherwise, we call the destroy() callback.
>> */
>> for (i = 0; i < max_parsed; ++i) {
>> - if (!(parsed_attrs & (1 << i)))
>> + if (!(parsed_attrs & BIT(i)))
>> continue;
>>
>> param = &seg6_action_params[i];
>> --
>> 2.29.2
>>
>
> Hi Colin,
> thanks for the fix. I've just given a look a the whole seg6_local.c code and I
> found that such issues is present in other parts of the code.
>
> If we agree, I can make a fix which explicitly eliminates the several (1 << i)
> in favor of BIT(i).

Sounds good to me.

Colin

>
> Andrea
>