[v1] hw/net/rocker: Avoid undefined shifts with more than 31 ports

[PATCH] hw/net/rocker: Avoid undefined shifts with more than 31 ports

Posted by Peter Maydell 1 year, 9 months ago

In rocker_port_phys_link_status() and rocker_port_phys_enable_read()
we construct a 64-bit value with one bit per front-panel port.
However we accidentally do the shift as 32-bit arithmetic, which
means that if there are more than 31 front-panel ports this is
undefined behaviour.

Fix the problem by ensuring we use 64-bit arithmetic for the whole
calculation. (We won't ever shift off the 64-bit value because
ROCKER_FP_PORTS_MAX is 62.)

Resolves: Coverity CID 1487121, 1487160
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 hw/net/rocker/rocker.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/hw/net/rocker/rocker.c b/hw/net/rocker/rocker.c
index 31f2340fb91..d8f3f16fe87 100644
--- a/hw/net/rocker/rocker.c
+++ b/hw/net/rocker/rocker.c
@@ -1010,7 +1010,7 @@ static uint64_t rocker_port_phys_link_status(Rocker *r)
         FpPort *port = r->fp_port[i];
 
         if (fp_port_get_link_up(port)) {
-            status |= 1 << (i + 1);
+            status |= 1ULL << (i + 1);
         }
     }
     return status;
@@ -1025,7 +1025,7 @@ static uint64_t rocker_port_phys_enable_read(Rocker *r)
         FpPort *port = r->fp_port[i];
 
         if (fp_port_enabled(port)) {
-            ret |= 1 << (i + 1);
+            ret |= 1ULL << (i + 1);
         }
     }
     return ret;
-- 
2.25.1

Re: [PATCH] hw/net/rocker: Avoid undefined shifts with more than 31 ports

Posted by Peter Maydell 1 year, 8 months ago

Ping?

thanks
-- PMM

On Fri, 29 Jul 2022 at 16:59, Peter Maydell <peter.maydell@linaro.org> wrote:
>
> In rocker_port_phys_link_status() and rocker_port_phys_enable_read()
> we construct a 64-bit value with one bit per front-panel port.
> However we accidentally do the shift as 32-bit arithmetic, which
> means that if there are more than 31 front-panel ports this is
> undefined behaviour.
>
> Fix the problem by ensuring we use 64-bit arithmetic for the whole
> calculation. (We won't ever shift off the 64-bit value because
> ROCKER_FP_PORTS_MAX is 62.)
>
> Resolves: Coverity CID 1487121, 1487160
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> ---
>  hw/net/rocker/rocker.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/hw/net/rocker/rocker.c b/hw/net/rocker/rocker.c
> index 31f2340fb91..d8f3f16fe87 100644
> --- a/hw/net/rocker/rocker.c
> +++ b/hw/net/rocker/rocker.c
> @@ -1010,7 +1010,7 @@ static uint64_t rocker_port_phys_link_status(Rocker *r)
>          FpPort *port = r->fp_port[i];
>
>          if (fp_port_get_link_up(port)) {
> -            status |= 1 << (i + 1);
> +            status |= 1ULL << (i + 1);
>          }
>      }
>      return status;
> @@ -1025,7 +1025,7 @@ static uint64_t rocker_port_phys_enable_read(Rocker *r)
>          FpPort *port = r->fp_port[i];
>
>          if (fp_port_enabled(port)) {
> -            ret |= 1 << (i + 1);
> +            ret |= 1ULL << (i + 1);
>          }
>      }
>      return ret;

Re: [PATCH] hw/net/rocker: Avoid undefined shifts with more than 31 ports

Posted by Richard Henderson 1 year, 8 months ago

On 8/4/22 03:45, Peter Maydell wrote:
> Ping?
> 
> thanks
> -- PMM
> 
> On Fri, 29 Jul 2022 at 16:59, Peter Maydell <peter.maydell@linaro.org> wrote:
>>
>> In rocker_port_phys_link_status() and rocker_port_phys_enable_read()
>> we construct a 64-bit value with one bit per front-panel port.
>> However we accidentally do the shift as 32-bit arithmetic, which
>> means that if there are more than 31 front-panel ports this is
>> undefined behaviour.
>>
>> Fix the problem by ensuring we use 64-bit arithmetic for the whole
>> calculation. (We won't ever shift off the 64-bit value because
>> ROCKER_FP_PORTS_MAX is 62.)
>>
>> Resolves: Coverity CID 1487121, 1487160
>> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>


r~

>> ---
>>   hw/net/rocker/rocker.c | 4 ++--
>>   1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/hw/net/rocker/rocker.c b/hw/net/rocker/rocker.c
>> index 31f2340fb91..d8f3f16fe87 100644
>> --- a/hw/net/rocker/rocker.c
>> +++ b/hw/net/rocker/rocker.c
>> @@ -1010,7 +1010,7 @@ static uint64_t rocker_port_phys_link_status(Rocker *r)
>>           FpPort *port = r->fp_port[i];
>>
>>           if (fp_port_get_link_up(port)) {
>> -            status |= 1 << (i + 1);
>> +            status |= 1ULL << (i + 1);
>>           }
>>       }
>>       return status;
>> @@ -1025,7 +1025,7 @@ static uint64_t rocker_port_phys_enable_read(Rocker *r)
>>           FpPort *port = r->fp_port[i];
>>
>>           if (fp_port_enabled(port)) {
>> -            ret |= 1 << (i + 1);
>> +            ret |= 1ULL << (i + 1);
>>           }
>>       }
>>       return ret;
>

Re: [PATCH] hw/net/rocker: Avoid undefined shifts with more than 31 ports

Posted by Jason Wang 1 year, 8 months ago

On Thu, Aug 4, 2022 at 11:27 PM Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> On 8/4/22 03:45, Peter Maydell wrote:
> > Ping?
> >
> > thanks
> > -- PMM
> >
> > On Fri, 29 Jul 2022 at 16:59, Peter Maydell <peter.maydell@linaro.org> wrote:
> >>
> >> In rocker_port_phys_link_status() and rocker_port_phys_enable_read()
> >> we construct a 64-bit value with one bit per front-panel port.
> >> However we accidentally do the shift as 32-bit arithmetic, which
> >> means that if there are more than 31 front-panel ports this is
> >> undefined behaviour.
> >>
> >> Fix the problem by ensuring we use 64-bit arithmetic for the whole
> >> calculation. (We won't ever shift off the 64-bit value because
> >> ROCKER_FP_PORTS_MAX is 62.)
> >>
> >> Resolves: Coverity CID 1487121, 1487160
> >> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
>
> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

Queued.

Thanks

>
>
> r~
>
> >> ---
> >>   hw/net/rocker/rocker.c | 4 ++--
> >>   1 file changed, 2 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/hw/net/rocker/rocker.c b/hw/net/rocker/rocker.c
> >> index 31f2340fb91..d8f3f16fe87 100644
> >> --- a/hw/net/rocker/rocker.c
> >> +++ b/hw/net/rocker/rocker.c
> >> @@ -1010,7 +1010,7 @@ static uint64_t rocker_port_phys_link_status(Rocker *r)
> >>           FpPort *port = r->fp_port[i];
> >>
> >>           if (fp_port_get_link_up(port)) {
> >> -            status |= 1 << (i + 1);
> >> +            status |= 1ULL << (i + 1);
> >>           }
> >>       }
> >>       return status;
> >> @@ -1025,7 +1025,7 @@ static uint64_t rocker_port_phys_enable_read(Rocker *r)
> >>           FpPort *port = r->fp_port[i];
> >>
> >>           if (fp_port_enabled(port)) {
> >> -            ret |= 1 << (i + 1);
> >> +            ret |= 1ULL << (i + 1);
> >>           }
> >>       }
> >>       return ret;
> >
>