* [PATCH v2] ethtool: avoiding integer overflow in ethtool_phys_id()
@ 2022-11-22 6:54 Maxim Korotkov
2022-11-22 12:14 ` Alexander Lobakin
0 siblings, 1 reply; 2+ messages in thread
From: Maxim Korotkov @ 2022-11-22 6:54 UTC (permalink / raw)
To: David S. Miller
Cc: Maxim Korotkov, Eric Dumazet, Jakub Kicinski, Paolo Abeni,
Guangbin Huang, Andrew Lunn, Alexander Lobakin, Keller, Jacob E,
Tom Rix, Marco Bonelli, Edward Cree, netdev, linux-kernel,
lvc-project
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 <korotkov.maxim.s@gmail.com>
---
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..f845e8be4d7c 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
^ permalink raw reply related [flat|nested] 2+ messages in thread* Re: [PATCH v2] ethtool: avoiding integer overflow in ethtool_phys_id()
2022-11-22 6:54 [PATCH v2] ethtool: avoiding integer overflow in ethtool_phys_id() Maxim Korotkov
@ 2022-11-22 12:14 ` Alexander Lobakin
0 siblings, 0 replies; 2+ messages in thread
From: Alexander Lobakin @ 2022-11-22 12:14 UTC (permalink / raw)
To: Maxim Korotkov
Cc: Alexander Lobakin, David S. Miller, Eric Dumazet, Jakub Kicinski,
Paolo Abeni, Guangbin Huang, Andrew Lunn, Keller, Jacob E,
Tom Rix, Marco Bonelli, Edward Cree, netdev, linux-kernel,
lvc-project
From: Maxim Korotkov <korotkov.maxim.s@gmail.com>
Date: Tue, 22 Nov 2022 09:54:23 +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 <korotkov.maxim.s@gmail.com>
> ---
> 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..f845e8be4d7c 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);
^^
Meh, you forgot to put a space after the comma :s
Other than that (please add it to a v3):
Reviewed-by: Alexander Lobakin <alexandr.lobakin@intel.com>
> + u64 i = 0;
>
> do {
> rtnl_lock();
> --
> 2.17.1
Thanks,
Olek
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