The value of an arithmetic expression "n * id.data" is subject
to possible overflow due to a failure to cast operands to a larger data
type before performing arithmetic. Used macro for multiplication instead
operator for avoiding overflow.
Found by Linux Verification Center (linuxtesting.org) with SVACE.
Signed-off-by: Maxim Korotkov <[email protected]>
---
net/ethtool/ioctl.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/net/ethtool/ioctl.c b/net/ethtool/ioctl.c
index 6a7308de192d..6b59e7a1c906 100644
--- a/net/ethtool/ioctl.c
+++ b/net/ethtool/ioctl.c
@@ -2007,7 +2007,8 @@ static int ethtool_phys_id(struct net_device *dev, void __user *useraddr)
} else {
/* Driver expects to be called at twice the frequency in rc */
int n = rc * 2, interval = HZ / n;
- u64 count = n * id.data, i = 0;
+ u64 count = mul_u32_u32(n, id.data);
+ u64 i = 0;
do {
rtnl_lock();
--
2.17.1
From: Maxim Korotkov <[email protected]>
Date: Tue, 22 Nov 2022 15:29:01 +0300
> The value of an arithmetic expression "n * id.data" is subject
> to possible overflow due to a failure to cast operands to a larger data
> type before performing arithmetic. Used macro for multiplication instead
> operator for avoiding overflow.
>
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
>
> Signed-off-by: Maxim Korotkov <[email protected]>
Reviewed-by: Alexander Lobakin <[email protected]>
> ---
> net/ethtool/ioctl.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/net/ethtool/ioctl.c b/net/ethtool/ioctl.c
> index 6a7308de192d..6b59e7a1c906 100644
> --- a/net/ethtool/ioctl.c
> +++ b/net/ethtool/ioctl.c
> @@ -2007,7 +2007,8 @@ static int ethtool_phys_id(struct net_device *dev, void __user *useraddr)
> } else {
> /* Driver expects to be called at twice the frequency in rc */
> int n = rc * 2, interval = HZ / n;
> - u64 count = n * id.data, i = 0;
> + u64 count = mul_u32_u32(n, id.data);
> + u64 i = 0;
>
> do {
> rtnl_lock();
> --
> 2.17.1
Some notes to the process, not the code:
1) I asked to add my Reviewed-by to v3 in the previous thread, it's
mandatory for authors to pick-up all the tags before publishing
a new revision;
2) when sending v2, v3, ... vN, please have a changelog in the
commit message or right below those '---' after your SoB, that
makes it easier to review.
Thanks,
Olek
On Tue, Nov 22, 2022 at 03:29:01PM +0300, Maxim Korotkov wrote:
> The value of an arithmetic expression "n * id.data" is subject
> to possible overflow due to a failure to cast operands to a larger data
> type before performing arithmetic. Used macro for multiplication instead
> operator for avoiding overflow.
>
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
>
> Signed-off-by: Maxim Korotkov <[email protected]>
Reviewed-by: Andrew Lunn <[email protected]>
Andrew
On Tue, 22 Nov 2022 15:29:01 +0300 Maxim Korotkov wrote:
> The value of an arithmetic expression "n * id.data" is subject
> to possible overflow due to a failure to cast operands to a larger data
> type before performing arithmetic. Used macro for multiplication instead
> operator for avoiding overflow.
>
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
>
> Signed-off-by: Maxim Korotkov <[email protected]>
Applying to net-next, pretty sure nobody expects us to support blinking
an LED 4 billion times, at a rate low enough for a human eye to see...
But let's watch the stable bots pick it up anyway.
Hello:
This patch was applied to netdev/net-next.git (master)
by Jakub Kicinski <[email protected]>:
On Tue, 22 Nov 2022 15:29:01 +0300 you wrote:
> The value of an arithmetic expression "n * id.data" is subject
> to possible overflow due to a failure to cast operands to a larger data
> type before performing arithmetic. Used macro for multiplication instead
> operator for avoiding overflow.
>
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
>
> [...]
Here is the summary with links:
- [v3] ethtool: avoiding integer overflow in ethtool_phys_id()
https://git.kernel.org/netdev/net-next/c/64a8f8f7127d
You are awesome, thank you!
--
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