Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  1) // SPDX-License-Identifier: GPL-2.0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  3)  * Ioctl to get a verity file's digest
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  4)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  5)  * Copyright 2019 Google LLC
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  6)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  7) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  8) #include "fsverity_private.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  9) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) #include <linux/uaccess.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13)  * fsverity_ioctl_measure() - get a verity file's digest
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14)  * @filp: file to get digest of
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15)  * @_uarg: user pointer to fsverity_digest
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17)  * Retrieve the file digest that the kernel is enforcing for reads from a verity
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18)  * file.  See the "FS_IOC_MEASURE_VERITY" section of
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19)  * Documentation/filesystems/fsverity.rst for the documentation.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21)  * Return: 0 on success, -errno on failure
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) int fsverity_ioctl_measure(struct file *filp, void __user *_uarg)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25) 	const struct inode *inode = file_inode(filp);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) 	struct fsverity_digest __user *uarg = _uarg;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) 	const struct fsverity_info *vi;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) 	const struct fsverity_hash_alg *hash_alg;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) 	struct fsverity_digest arg;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) 	vi = fsverity_get_info(inode);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) 	if (!vi)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) 		return -ENODATA; /* not a verity file */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) 	hash_alg = vi->tree_params.hash_alg;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) 	 * The user specifies the digest_size their buffer has space for; we can
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) 	 * return the digest if it fits in the available space.  We write back
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) 	 * the actual size, which may be shorter than the user-specified size.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) 	if (get_user(arg.digest_size, &uarg->digest_size))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) 		return -EFAULT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) 	if (arg.digest_size < hash_alg->digest_size)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45) 		return -EOVERFLOW;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47) 	memset(&arg, 0, sizeof(arg));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) 	arg.digest_algorithm = hash_alg - fsverity_hash_algs;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) 	arg.digest_size = hash_alg->digest_size;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51) 	if (copy_to_user(uarg, &arg, sizeof(arg)))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52) 		return -EFAULT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54) 	if (copy_to_user(uarg->digest, vi->file_digest, hash_alg->digest_size))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) 		return -EFAULT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59) EXPORT_SYMBOL_GPL(fsverity_ioctl_measure);