[PATCH 6.0 0954/1073] ethtool: avoiding integer overflow in ethtool_phys_id()

Greg Kroah-Hartman
2022-12-28T16:48:12Z

From: Maxim Korotkov <korotkov.maxim.s@gmail.com>

[ Upstream commit 64a8f8f7127da228d59a39e2c5e75f86590f90b4 ]

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>
Reviewed-by: Alexander Lobakin <alexandr.lobakin@intel.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/20221122122901.22294-1-korotkov.maxim.s@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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();
--
2.35.1