Re: [RFC v3 6/9] kmsg: add ioctl for adding and deleting kmsg* devices
flat view
From: Arnd Bergmann <arnd@arndb.de>
Date: 2015-10-19 13:19:50
Also in:
lkml
On Monday 19 October 2015 14:58:20 Paul Osmialowski wrote:
quoted hunk ↗ jump to hunk
+ +struct kmsg_cmd_buffer_add { + size_t size; + unsigned short mode; + int minor; +} __attribute__((packed)); + +#define KMSG_IOCTL_MAGIC 0xBB + +/*
Try to avoid using packed unaligned data structures. Here I would just use __u64 and __u32 members.
quoted hunk ↗ jump to hunk
+ case KMSG_CMD_BUFFER_ADD: + if (copy_from_user(&size, argp, sizeof(size))) + return -EFAULT; + argp += sizeof(size); + if (copy_from_user(&mode, argp, sizeof(mode))) + return -EFAULT;
This is a rather unusual way to access the data. Just copy the entire structure to the stack. Arnd