From: Maxim Korotkov Date: Tue, 22 Nov 2022 12:29:01 +0000 (+0300) Subject: ethtool: avoiding integer overflow in ethtool_phys_id() X-Git-Tag: v6.0.16~123 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2f8f15f3f2fd1063bcef0374b4bfa6c374e7a4d3;p=thirdparty%2Fkernel%2Fstable.git ethtool: avoiding integer overflow in ethtool_phys_id() [ 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 Reviewed-by: Alexander Lobakin Reviewed-by: Andrew Lunn Link: https://lore.kernel.org/r/20221122122901.22294-1-korotkov.maxim.s@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- diff --git a/net/ethtool/ioctl.c b/net/ethtool/ioctl.c index 6a7308de192d9..6b59e7a1c9063 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();