RE: [PATCH] net: sched: taprio: Fix potential integer overflow in taprio_set_picos_per_byte
Hi Vladimir, > Looks ok to me, but I have no saying over ethtool API. Actually I don't even > know whom to ask - the output of ./scripts/get_maintainer.pl > net/core/ethtool.c is a bit overwhelming. > To avoid conflicts, there needs to be somebody out of us who takes Eric's > simplification, with Gustavo's Reported-by tag, and the 2 ethtool & taprio > patches to avoid division by zero, and the printing fix, and maybe do the > same in > cbs. Will you be the one? Should I? If you have the cycles to do it, go for it. I would only be able to work on this next week. > > Thanks, > -Vladimir Thanks a lot, -- Vinicius
Re: [PATCH] net: sched: taprio: Fix potential integer overflow in taprio_set_picos_per_byte
Hi Vinicius,
On Wed, 4 Sep 2019 at 00:26, Vinicius Costa Gomes
wrote:
>
> Hi,
>
> Vladimir Oltean writes:
>
> > Right. And while we're at it, there's still the potential
> > division-by-zero problem which I still don't know how to solve without
> > implementing a full-blown __ethtool_get_link_ksettings parser that
> > checks against all the possible outputs it can have under the "no
> > carrier" condition - see "[RFC PATCH 1/1] phylink: Set speed to
> > SPEED_UNKNOWN when there is no PHY connected" for details.
> > And there's also a third fix to be made: the netdev_dbg should be made
> > to print "speed" instead of "ecmd.base.speed".
>
> For the ksettings part I am thinking on adding something like this to
> ethtool.c. Do you think anything is missing (apart from the
> documentation)?
>
> ->
>
> diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h
> index 95991e43..d37c80b 100644
> --- a/include/linux/ethtool.h
> +++ b/include/linux/ethtool.h
> @@ -177,6 +177,9 @@ void ethtool_convert_legacy_u32_to_link_mode(unsigned
> long *dst,
> bool ethtool_convert_link_mode_to_legacy_u32(u32 *legacy_u32,
> const unsigned long *src);
>
> +u32 ethtool_link_ksettings_to_speed(const struct ethtool_link_ksettings
> *settings,
> + u32 default_speed);
> +
> /**
> * struct ethtool_ops - optional netdev operations
> * @get_drvinfo: Report driver/device information. Should only set the
> diff --git a/net/core/ethtool.c b/net/core/ethtool.c
> index 6288e69..80e3db3 100644
> --- a/net/core/ethtool.c
> +++ b/net/core/ethtool.c
> @@ -539,6 +539,18 @@ struct ethtool_link_usettings {
> } link_modes;
> };
>
> +u32 ethtool_link_ksettings_to_speed(const struct ethtool_link_ksettings
> *settings,
> + u32 default_speed)
> +{
> + if (settings->base.speed == SPEED_UNKNOWN)
> + return default_speed;
> +
> + if (settings->base.speed == 0)
> + return default_speed;
> +
> + return settings->base.speed;
> +}
> +
> /* Internal kernel helper to query a device ethtool_link_settings. */
> int __ethtool_get_link_ksettings(struct net_device *dev,
> struct ethtool_link_ksettings
> *link_ksettings)
Looks ok to me, but I have no saying over ethtool API. Actually I
don't even know whom to ask - the output of
./scripts/get_maintainer.pl net/core/ethtool.c is a bit overwhelming.
To avoid conflicts, there needs to be somebody out of us who takes
Eric's simplification, with Gustavo's Reported-by tag, and the 2
ethtool & taprio patches to avoid division by zero, and the printing
fix, and maybe do the same in cbs. Will you be the one? Should I?
Thanks,
-Vladimir
Re: [PATCH] net: sched: taprio: Fix potential integer overflow in taprio_set_picos_per_byte
Hi,
Vladimir Oltean writes:
> Right. And while we're at it, there's still the potential
> division-by-zero problem which I still don't know how to solve without
> implementing a full-blown __ethtool_get_link_ksettings parser that
> checks against all the possible outputs it can have under the "no
> carrier" condition - see "[RFC PATCH 1/1] phylink: Set speed to
> SPEED_UNKNOWN when there is no PHY connected" for details.
> And there's also a third fix to be made: the netdev_dbg should be made
> to print "speed" instead of "ecmd.base.speed".
For the ksettings part I am thinking on adding something like this to
ethtool.c. Do you think anything is missing (apart from the
documentation)?
->
diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h
index 95991e43..d37c80b 100644
--- a/include/linux/ethtool.h
+++ b/include/linux/ethtool.h
@@ -177,6 +177,9 @@ void ethtool_convert_legacy_u32_to_link_mode(unsigned long
*dst,
bool ethtool_convert_link_mode_to_legacy_u32(u32 *legacy_u32,
const unsigned long *src);
+u32 ethtool_link_ksettings_to_speed(const struct ethtool_link_ksettings
*settings,
+ u32 default_speed);
+
/**
* struct ethtool_ops - optional netdev operations
* @get_drvinfo: Report driver/device information. Should only set the
diff --git a/net/core/ethtool.c b/net/core/ethtool.c
index 6288e69..80e3db3 100644
--- a/net/core/ethtool.c
+++ b/net/core/ethtool.c
@@ -539,6 +539,18 @@ struct ethtool_link_usettings {
} link_modes;
};
+u32 ethtool_link_ksettings_to_speed(const struct ethtool_link_ksettings
*settings,
+ u32 default_speed)
+{
+ if (settings->base.speed == SPEED_UNKNOWN)
+ return default_speed;
+
+ if (settings->base.speed == 0)
+ return default_speed;
+
+ return settings->base.speed;
+}
+
/* Internal kernel helper to query a device ethtool_link_settings. */
int __ethtool_get_link_ksettings(struct net_device *dev,
struct ethtool_link_ksettings *link_ksettings)
Re: [PATCH] net: sched: taprio: Fix potential integer overflow in taprio_set_picos_per_byte
On Tue, 3 Sep 2019 at 10:19, Eric Dumazet wrote:
>
>
>
> On 9/3/19 3:08 AM, Gustavo A. R. Silva wrote:
> > Add suffix LL to constant 1000 in order to avoid a potential integer
> > overflow and give the compiler complete information about the proper
> > arithmetic to use. Notice that this constant is being used in a context
> > that expects an expression of type s64, but it's currently evaluated
> > using 32-bit arithmetic.
> >
> > Addresses-Coverity-ID: 1453459 ("Unintentional integer overflow")
> > Fixes: f04b514c0ce2 ("taprio: Set default link speed to 10 Mbps in
> > taprio_set_picos_per_byte")
> > Signed-off-by: Gustavo A. R. Silva
> > ---
> > net/sched/sch_taprio.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/net/sched/sch_taprio.c b/net/sched/sch_taprio.c
> > index 8d8bc2ec5cd6..956f837436ea 100644
> > --- a/net/sched/sch_taprio.c
> > +++ b/net/sched/sch_taprio.c
> > @@ -966,7 +966,7 @@ static void taprio_set_picos_per_byte(struct net_device
> > *dev,
> >
> > skip:
> > picos_per_byte = div64_s64(NSEC_PER_SEC * 1000LL * 8,
> > -speed * 1000 * 1000);
> > +speed * 1000LL * 1000);
> >
> > atomic64_set(>picos_per_byte, picos_per_byte);
> > netdev_dbg(dev, "taprio: set %s's picos_per_byte to: %lld, linkspeed:
> > %d\n",
> >
>
> But, why even multiplying by 1,000,000 in the first place, this seems silly,
> a standard 32 bit divide could be used instead.
>
> ->
>
> diff --git a/net/sched/sch_taprio.c b/net/sched/sch_taprio.c
> index
> 8d8bc2ec5cd6281d811fd5d8a5c5211ebb0edd73..944b1af3215668e927d486b6c6c65c4599fb9539
> 100644
> --- a/net/sched/sch_taprio.c
> +++ b/net/sched/sch_taprio.c
> @@ -965,8 +965,7 @@ static void taprio_set_picos_per_byte(struct net_device
> *dev,
> speed = ecmd.base.speed;
>
> skip:
> - picos_per_byte = div64_s64(NSEC_PER_SEC * 1000LL * 8,
> - speed * 1000 * 1000);
> + picos_per_byte = (USEC_PER_SEC * 8) / speed;
>
> atomic64_set(>picos_per_byte, picos_per_byte);
> netdev_dbg(dev, "taprio: set %s's picos_per_byte to: %lld, linkspeed:
> %d\n",
>
>
>
Right. And while we're at it, there's still the potential
division-by-zero problem which I still don't know how to solve without
implementing a full-blown __ethtool_get_link_ksettings parser that
checks against all the possible outputs it can have under the "no
carrier" condition - see "[RFC PATCH 1/1] phylink: Set speed to
SPEED_UNKNOWN when there is no PHY connected" for details.
And there's also a third fix to be made: the netdev_dbg should be made
to print "speed" instead of "ecmd.base.speed".
Thanks,
-Vladimir
Re: [PATCH] net: sched: taprio: Fix potential integer overflow in taprio_set_picos_per_byte
On 9/3/19 3:08 AM, Gustavo A. R. Silva wrote:
> Add suffix LL to constant 1000 in order to avoid a potential integer
> overflow and give the compiler complete information about the proper
> arithmetic to use. Notice that this constant is being used in a context
> that expects an expression of type s64, but it's currently evaluated
> using 32-bit arithmetic.
>
> Addresses-Coverity-ID: 1453459 ("Unintentional integer overflow")
> Fixes: f04b514c0ce2 ("taprio: Set default link speed to 10 Mbps in
> taprio_set_picos_per_byte")
> Signed-off-by: Gustavo A. R. Silva
> ---
> net/sched/sch_taprio.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/net/sched/sch_taprio.c b/net/sched/sch_taprio.c
> index 8d8bc2ec5cd6..956f837436ea 100644
> --- a/net/sched/sch_taprio.c
> +++ b/net/sched/sch_taprio.c
> @@ -966,7 +966,7 @@ static void taprio_set_picos_per_byte(struct net_device
> *dev,
>
> skip:
> picos_per_byte = div64_s64(NSEC_PER_SEC * 1000LL * 8,
> -speed * 1000 * 1000);
> +speed * 1000LL * 1000);
>
> atomic64_set(>picos_per_byte, picos_per_byte);
> netdev_dbg(dev, "taprio: set %s's picos_per_byte to: %lld, linkspeed:
> %d\n",
>
But, why even multiplying by 1,000,000 in the first place, this seems silly,
a standard 32 bit divide could be used instead.
->
diff --git a/net/sched/sch_taprio.c b/net/sched/sch_taprio.c
index
8d8bc2ec5cd6281d811fd5d8a5c5211ebb0edd73..944b1af3215668e927d486b6c6c65c4599fb9539
100644
--- a/net/sched/sch_taprio.c
+++ b/net/sched/sch_taprio.c
@@ -965,8 +965,7 @@ static void taprio_set_picos_per_byte(struct net_device
*dev,
speed = ecmd.base.speed;
skip:
- picos_per_byte = div64_s64(NSEC_PER_SEC * 1000LL * 8,
- speed * 1000 * 1000);
+ picos_per_byte = (USEC_PER_SEC * 8) / speed;
atomic64_set(>picos_per_byte, picos_per_byte);
netdev_dbg(dev, "taprio: set %s's picos_per_byte to: %lld, linkspeed:
%d\n",
Re: [PATCH] net: sched: taprio: Fix potential integer overflow in taprio_set_picos_per_byte
On Tue, 3 Sep 2019 at 04:08, Gustavo A. R. Silva wrote:
>
> Add suffix LL to constant 1000 in order to avoid a potential integer
> overflow and give the compiler complete information about the proper
> arithmetic to use. Notice that this constant is being used in a context
> that expects an expression of type s64, but it's currently evaluated
> using 32-bit arithmetic.
>
> Addresses-Coverity-ID: 1453459 ("Unintentional integer overflow")
> Fixes: f04b514c0ce2 ("taprio: Set default link speed to 10 Mbps in
> taprio_set_picos_per_byte")
> Signed-off-by: Gustavo A. R. Silva
> ---
Acked-by: Vladimir Oltean
> net/sched/sch_taprio.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/net/sched/sch_taprio.c b/net/sched/sch_taprio.c
> index 8d8bc2ec5cd6..956f837436ea 100644
> --- a/net/sched/sch_taprio.c
> +++ b/net/sched/sch_taprio.c
> @@ -966,7 +966,7 @@ static void taprio_set_picos_per_byte(struct net_device
> *dev,
>
> skip:
> picos_per_byte = div64_s64(NSEC_PER_SEC * 1000LL * 8,
> - speed * 1000 * 1000);
> + speed * 1000LL * 1000);
>
> atomic64_set(>picos_per_byte, picos_per_byte);
> netdev_dbg(dev, "taprio: set %s's picos_per_byte to: %lld, linkspeed:
> %d\n",
> --
> 2.23.0
>
[PATCH] net: sched: taprio: Fix potential integer overflow in taprio_set_picos_per_byte
Add suffix LL to constant 1000 in order to avoid a potential integer
overflow and give the compiler complete information about the proper
arithmetic to use. Notice that this constant is being used in a context
that expects an expression of type s64, but it's currently evaluated
using 32-bit arithmetic.
Addresses-Coverity-ID: 1453459 ("Unintentional integer overflow")
Fixes: f04b514c0ce2 ("taprio: Set default link speed to 10 Mbps in
taprio_set_picos_per_byte")
Signed-off-by: Gustavo A. R. Silva
---
net/sched/sch_taprio.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/sched/sch_taprio.c b/net/sched/sch_taprio.c
index 8d8bc2ec5cd6..956f837436ea 100644
--- a/net/sched/sch_taprio.c
+++ b/net/sched/sch_taprio.c
@@ -966,7 +966,7 @@ static void taprio_set_picos_per_byte(struct net_device
*dev,
skip:
picos_per_byte = div64_s64(NSEC_PER_SEC * 1000LL * 8,
- speed * 1000 * 1000);
+ speed * 1000LL * 1000);
atomic64_set(>picos_per_byte, picos_per_byte);
netdev_dbg(dev, "taprio: set %s's picos_per_byte to: %lld, linkspeed:
%d\n",
--
2.23.0
