Author | Tokens | Token Proportion | Commits | Commit Proportion |
---|---|---|---|---|
Eric Biggers | 692 | 95.19% | 20 | 83.33% |
Mimi Zohar | 31 | 4.26% | 1 | 4.17% |
Linus Torvalds (pre-git) | 2 | 0.28% | 1 | 4.17% |
Matthew Wilcox | 1 | 0.14% | 1 | 4.17% |
Andrew Morton | 1 | 0.14% | 1 | 4.17% |
Total | 727 | 24 |
/* SPDX-License-Identifier: GPL-2.0 */ /* * fs-verity: read-only file-based authenticity protection * * This header declares the interface between the fs/verity/ support layer and * filesystems that support fs-verity. * * Copyright 2019 Google LLC */ #ifndef _LINUX_FSVERITY_H #define _LINUX_FSVERITY_H #include <linux/fs.h> #include <linux/mm.h> #include <crypto/hash_info.h> #include <crypto/sha2.h> #include <uapi/linux/fsverity.h> /* * Largest digest size among all hash algorithms supported by fs-verity. * Currently assumed to be <= size of fsverity_descriptor::root_hash. */ #define FS_VERITY_MAX_DIGEST_SIZE SHA512_DIGEST_SIZE /* Arbitrary limit to bound the kmalloc() size. Can be changed. */ #define FS_VERITY_MAX_DESCRIPTOR_SIZE 16384 /* Verity operations for filesystems */ struct fsverity_operations { /** * Begin enabling verity on the given file. * * @filp: a readonly file descriptor for the file * * The filesystem must do any needed filesystem-specific preparations * for enabling verity, e.g. evicting inline data. It also must return * -EBUSY if verity is already being enabled on the given file. * * i_rwsem is held for write. * * Return: 0 on success, -errno on failure */ int (*begin_enable_verity)(struct file *filp); /** * End enabling verity on the given file. * * @filp: a readonly file descriptor for the file * @desc: the verity descriptor to write, or NULL on failure * @desc_size: size of verity descriptor, or 0 on failure * @merkle_tree_size: total bytes the Merkle tree took up * * If desc == NULL, then enabling verity failed and the filesystem only * must do any necessary cleanups. Else, it must also store the given * verity descriptor to a fs-specific location associated with the inode * and do any fs-specific actions needed to mark the inode as a verity * inode, e.g. setting a bit in the on-disk inode. The filesystem is * also responsible for setting the S_VERITY flag in the VFS inode. * * i_rwsem is held for write, but it may have been dropped between * ->begin_enable_verity() and ->end_enable_verity(). * * Return: 0 on success, -errno on failure */ int (*end_enable_verity)(struct file *filp, const void *desc, size_t desc_size, u64 merkle_tree_size); /** * Get the verity descriptor of the given inode. * * @inode: an inode with the S_VERITY flag set * @buf: buffer in which to place the verity descriptor * @bufsize: size of @buf, or 0 to retrieve the size only * * If bufsize == 0, then the size of the verity descriptor is returned. * Otherwise the verity descriptor is written to 'buf' and its actual * size is returned; -ERANGE is returned if it's too large. This may be * called by multiple processes concurrently on the same inode. * * Return: the size on success, -errno on failure */ int (*get_verity_descriptor)(struct inode *inode, void *buf, size_t bufsize); /** * Read a Merkle tree page of the given inode. * * @inode: the inode * @index: 0-based index of the page within the Merkle tree * @num_ra_pages: The number of Merkle tree pages that should be * prefetched starting at @index if the page at @index * isn't already cached. Implementations may ignore this * argument; it's only a performance optimization. * * This can be called at any time on an open verity file. It may be * called by multiple processes concurrently, even with the same page. * * Note that this must retrieve a *page*, not necessarily a *block*. * * Return: the page on success, ERR_PTR() on failure */ struct page *(*read_merkle_tree_page)(struct inode *inode, pgoff_t index, unsigned long num_ra_pages); /** * Write a Merkle tree block to the given inode. * * @inode: the inode for which the Merkle tree is being built * @buf: the Merkle tree block to write * @pos: the position of the block in the Merkle tree (in bytes) * @size: the Merkle tree block size (in bytes) * * This is only called between ->begin_enable_verity() and * ->end_enable_verity(). * * Return: 0 on success, -errno on failure */ int (*write_merkle_tree_block)(struct inode *inode, const void *buf, u64 pos, unsigned int size); }; #ifdef CONFIG_FS_VERITY static inline struct fsverity_info *fsverity_get_info(const struct inode *inode) { /* * Pairs with the cmpxchg_release() in fsverity_set_info(). * I.e., another task may publish ->i_verity_info concurrently, * executing a RELEASE barrier. We need to use smp_load_acquire() here * to safely ACQUIRE the memory the other task published. */ return smp_load_acquire(&inode->i_verity_info); } /* enable.c */ int fsverity_ioctl_enable(struct file *filp, const void __user *arg); /* measure.c */ int fsverity_ioctl_measure(struct file *filp, void __user *arg); int fsverity_get_digest(struct inode *inode, u8 raw_digest[FS_VERITY_MAX_DIGEST_SIZE], u8 *alg, enum hash_algo *halg); /* open.c */ int __fsverity_file_open(struct inode *inode, struct file *filp); int __fsverity_prepare_setattr(struct dentry *dentry, struct iattr *attr); void __fsverity_cleanup_inode(struct inode *inode); /** * fsverity_cleanup_inode() - free the inode's verity info, if present * @inode: an inode being evicted * * Filesystems must call this on inode eviction to free ->i_verity_info. */ static inline void fsverity_cleanup_inode(struct inode *inode) { if (inode->i_verity_info) __fsverity_cleanup_inode(inode); } /* read_metadata.c */ int fsverity_ioctl_read_metadata(struct file *filp, const void __user *uarg); /* verify.c */ bool fsverity_verify_blocks(struct folio *folio, size_t len, size_t offset); void fsverity_verify_bio(struct bio *bio); void fsverity_enqueue_verify_work(struct work_struct *work); #else /* !CONFIG_FS_VERITY */ static inline struct fsverity_info *fsverity_get_info(const struct inode *inode) { return NULL; } /* enable.c */ static inline int fsverity_ioctl_enable(struct file *filp, const void __user *arg) { return -EOPNOTSUPP; } /* measure.c */ static inline int fsverity_ioctl_measure(struct file *filp, void __user *arg) { return -EOPNOTSUPP; } static inline int fsverity_get_digest(struct inode *inode, u8 raw_digest[FS_VERITY_MAX_DIGEST_SIZE], u8 *alg, enum hash_algo *halg) { /* * fsverity is not enabled in the kernel configuration, so always report * that the file doesn't have fsverity enabled (digest size 0). */ return 0; } /* open.c */ static inline int __fsverity_file_open(struct inode *inode, struct file *filp) { return -EOPNOTSUPP; } static inline int __fsverity_prepare_setattr(struct dentry *dentry, struct iattr *attr) { return -EOPNOTSUPP; } static inline void fsverity_cleanup_inode(struct inode *inode) { } /* read_metadata.c */ static inline int fsverity_ioctl_read_metadata(struct file *filp, const void __user *uarg) { return -EOPNOTSUPP; } /* verify.c */ static inline bool fsverity_verify_blocks(struct folio *folio, size_t len, size_t offset) { WARN_ON_ONCE(1); return false; } static inline void fsverity_verify_bio(struct bio *bio) { WARN_ON_ONCE(1); } static inline void fsverity_enqueue_verify_work(struct work_struct *work) { WARN_ON_ONCE(1); } #endif /* !CONFIG_FS_VERITY */ static inline bool fsverity_verify_folio(struct folio *folio) { return fsverity_verify_blocks(folio, folio_size(folio), 0); } static inline bool fsverity_verify_page(struct page *page) { return fsverity_verify_blocks(page_folio(page), PAGE_SIZE, 0); } /** * fsverity_active() - do reads from the inode need to go through fs-verity? * @inode: inode to check * * This checks whether ->i_verity_info has been set. * * Filesystems call this from ->readahead() to check whether the pages need to * be verified or not. Don't use IS_VERITY() for this purpose; it's subject to * a race condition where the file is being read concurrently with * FS_IOC_ENABLE_VERITY completing. (S_VERITY is set before ->i_verity_info.) * * Return: true if reads need to go through fs-verity, otherwise false */ static inline bool fsverity_active(const struct inode *inode) { return fsverity_get_info(inode) != NULL; } /** * fsverity_file_open() - prepare to open a verity file * @inode: the inode being opened * @filp: the struct file being set up * * When opening a verity file, deny the open if it is for writing. Otherwise, * set up the inode's ->i_verity_info if not already done. * * When combined with fscrypt, this must be called after fscrypt_file_open(). * Otherwise, we won't have the key set up to decrypt the verity metadata. * * Return: 0 on success, -errno on failure */ static inline int fsverity_file_open(struct inode *inode, struct file *filp) { if (IS_VERITY(inode)) return __fsverity_file_open(inode, filp); return 0; } /** * fsverity_prepare_setattr() - prepare to change a verity inode's attributes * @dentry: dentry through which the inode is being changed * @attr: attributes to change * * Verity files are immutable, so deny truncates. This isn't covered by the * open-time check because sys_truncate() takes a path, not a file descriptor. * * Return: 0 on success, -errno on failure */ static inline int fsverity_prepare_setattr(struct dentry *dentry, struct iattr *attr) { if (IS_VERITY(d_inode(dentry))) return __fsverity_prepare_setattr(dentry, attr); return 0; } #endif /* _LINUX_FSVERITY_H */
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