mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-09-21 10:01:00 +00:00
a4bbf53d88
Instead of looking up the algorithm by name in hash_algo_name[] to get its hash_algo ID, just store the hash_algo ID in the fsverity_hash_alg struct. Verify at boot time that every fsverity_hash_alg has a valid hash_algo ID with matching digest size. Remove an unnecessary memset() of the whole digest array to 0 before the digest is copied into it. Finally, remove the pr_debug statement. There is already a pr_debug for the fsverity digest when the file is opened. Signed-off-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com> Link: https://lore.kernel.org/r/20221129045139.69803-1-ebiggers@kernel.org
87 lines
2.4 KiB
C
87 lines
2.4 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
/*
|
|
* Ioctl to get a verity file's digest
|
|
*
|
|
* Copyright 2019 Google LLC
|
|
*/
|
|
|
|
#include "fsverity_private.h"
|
|
|
|
#include <linux/uaccess.h>
|
|
|
|
/**
|
|
* fsverity_ioctl_measure() - get a verity file's digest
|
|
* @filp: file to get digest of
|
|
* @_uarg: user pointer to fsverity_digest
|
|
*
|
|
* Retrieve the file digest that the kernel is enforcing for reads from a verity
|
|
* file. See the "FS_IOC_MEASURE_VERITY" section of
|
|
* Documentation/filesystems/fsverity.rst for the documentation.
|
|
*
|
|
* Return: 0 on success, -errno on failure
|
|
*/
|
|
int fsverity_ioctl_measure(struct file *filp, void __user *_uarg)
|
|
{
|
|
const struct inode *inode = file_inode(filp);
|
|
struct fsverity_digest __user *uarg = _uarg;
|
|
const struct fsverity_info *vi;
|
|
const struct fsverity_hash_alg *hash_alg;
|
|
struct fsverity_digest arg;
|
|
|
|
vi = fsverity_get_info(inode);
|
|
if (!vi)
|
|
return -ENODATA; /* not a verity file */
|
|
hash_alg = vi->tree_params.hash_alg;
|
|
|
|
/*
|
|
* The user specifies the digest_size their buffer has space for; we can
|
|
* return the digest if it fits in the available space. We write back
|
|
* the actual size, which may be shorter than the user-specified size.
|
|
*/
|
|
|
|
if (get_user(arg.digest_size, &uarg->digest_size))
|
|
return -EFAULT;
|
|
if (arg.digest_size < hash_alg->digest_size)
|
|
return -EOVERFLOW;
|
|
|
|
memset(&arg, 0, sizeof(arg));
|
|
arg.digest_algorithm = hash_alg - fsverity_hash_algs;
|
|
arg.digest_size = hash_alg->digest_size;
|
|
|
|
if (copy_to_user(uarg, &arg, sizeof(arg)))
|
|
return -EFAULT;
|
|
|
|
if (copy_to_user(uarg->digest, vi->file_digest, hash_alg->digest_size))
|
|
return -EFAULT;
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(fsverity_ioctl_measure);
|
|
|
|
/**
|
|
* fsverity_get_digest() - get a verity file's digest
|
|
* @inode: inode to get digest of
|
|
* @digest: (out) pointer to the digest
|
|
* @alg: (out) pointer to the hash algorithm enumeration
|
|
*
|
|
* Return the file hash algorithm and digest of an fsverity protected file.
|
|
* Assumption: before calling this, the file must have been opened.
|
|
*
|
|
* Return: 0 on success, -errno on failure
|
|
*/
|
|
int fsverity_get_digest(struct inode *inode,
|
|
u8 digest[FS_VERITY_MAX_DIGEST_SIZE],
|
|
enum hash_algo *alg)
|
|
{
|
|
const struct fsverity_info *vi;
|
|
const struct fsverity_hash_alg *hash_alg;
|
|
|
|
vi = fsverity_get_info(inode);
|
|
if (!vi)
|
|
return -ENODATA; /* not a verity file */
|
|
|
|
hash_alg = vi->tree_params.hash_alg;
|
|
memcpy(digest, vi->file_digest, hash_alg->digest_size);
|
|
*alg = hash_alg->algo_id;
|
|
return 0;
|
|
}
|