linux/fs/verity/open.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Opening fs-verity files
 *
 * Copyright 2019 Google LLC
 */

#include "fsverity_private.h"

#include <linux/mm.h>
#include <linux/slab.h>

static struct kmem_cache *fsverity_info_cachep;

/**
 * fsverity_init_merkle_tree_params() - initialize Merkle tree parameters
 * @params: the parameters struct to initialize
 * @inode: the inode for which the Merkle tree is being built
 * @hash_algorithm: number of hash algorithm to use
 * @log_blocksize: log base 2 of block size to use
 * @salt: pointer to salt (optional)
 * @salt_size: size of salt, possibly 0
 *
 * Validate the hash algorithm and block size, then compute the tree topology
 * (num levels, num blocks in each level, etc.) and initialize @params.
 *
 * Return: 0 on success, -errno on failure
 */
int fsverity_init_merkle_tree_params(struct merkle_tree_params *params,
				     const struct inode *inode,
				     unsigned int hash_algorithm,
				     unsigned int log_blocksize,
				     const u8 *salt, size_t salt_size)
{ … }

/*
 * Compute the file digest by hashing the fsverity_descriptor excluding the
 * builtin signature and with the sig_size field set to 0.
 */
static int compute_file_digest(const struct fsverity_hash_alg *hash_alg,
			       struct fsverity_descriptor *desc,
			       u8 *file_digest)
{ … }

/*
 * Create a new fsverity_info from the given fsverity_descriptor (with optional
 * appended builtin signature), and check the signature if present.  The
 * fsverity_descriptor must have already undergone basic validation.
 */
struct fsverity_info *fsverity_create_info(const struct inode *inode,
					   struct fsverity_descriptor *desc)
{ … }

void fsverity_set_info(struct inode *inode, struct fsverity_info *vi)
{ … }

void fsverity_free_info(struct fsverity_info *vi)
{ … }

static bool validate_fsverity_descriptor(struct inode *inode,
					 const struct fsverity_descriptor *desc,
					 size_t desc_size)
{ … }

/*
 * Read the inode's fsverity_descriptor (with optional appended builtin
 * signature) from the filesystem, and do basic validation of it.
 */
int fsverity_get_descriptor(struct inode *inode,
			    struct fsverity_descriptor **desc_ret)
{ … }

/* Ensure the inode has an ->i_verity_info */
static int ensure_verity_info(struct inode *inode)
{ … }

int __fsverity_file_open(struct inode *inode, struct file *filp)
{ … }
EXPORT_SYMBOL_GPL(…);

int __fsverity_prepare_setattr(struct dentry *dentry, struct iattr *attr)
{ … }
EXPORT_SYMBOL_GPL(…);

void __fsverity_cleanup_inode(struct inode *inode)
{ … }
EXPORT_SYMBOL_GPL(…);

void __init fsverity_init_info_cache(void)
{ … }