From 21dde05a95bb301d485ac2c332a80271213e67c3 Mon Sep 17 00:00:00 2001 From: Stephen Hemminger Date: Mon, 24 Jun 2019 09:47:11 -0700 Subject: [PATCH] kni: fix copy_from_user failure handling The correct thing to return if user gives a bad data is to return -EFAULT. Logging is also discouraged because it could be used as a DoS attack. Signed-off-by: Stephen Hemminger Acked-by: Ferruh Yigit --- kernel/linux/kni/kni_misc.c | 16 +++++----------- 1 file changed, 5 insertions(+), 11 deletions(-) diff --git a/kernel/linux/kni/kni_misc.c b/kernel/linux/kni/kni_misc.c index b59cf24c21..be45f82340 100644 --- a/kernel/linux/kni/kni_misc.c +++ b/kernel/linux/kni/kni_misc.c @@ -301,11 +301,8 @@ kni_ioctl_create(struct net *net, uint32_t ioctl_num, return -EINVAL; /* Copy kni info from user space */ - ret = copy_from_user(&dev_info, (void *)ioctl_param, sizeof(dev_info)); - if (ret) { - pr_err("copy_from_user in kni_ioctl_create"); - return -EIO; - } + if (copy_from_user(&dev_info, (void *)ioctl_param, sizeof(dev_info))) + return -EFAULT; /* Check if name is zero-ended */ if (strnlen(dev_info.name, sizeof(dev_info.name)) == sizeof(dev_info.name)) { @@ -427,15 +424,12 @@ kni_ioctl_release(struct net *net, uint32_t ioctl_num, if (_IOC_SIZE(ioctl_num) > sizeof(dev_info)) return -EINVAL; - ret = copy_from_user(&dev_info, (void *)ioctl_param, sizeof(dev_info)); - if (ret) { - pr_err("copy_from_user in kni_ioctl_release"); - return -EIO; - } + if (copy_from_user(&dev_info, (void *)ioctl_param, sizeof(dev_info))) + return -EFAULT; /* Release the network device according to its name */ if (strlen(dev_info.name) == 0) - return ret; + return -EINVAL; down_write(&knet->kni_list_lock); list_for_each_entry_safe(dev, n, &knet->kni_list_head, list) { -- 2.20.1