diff options
Diffstat (limited to 'include/linux/fsverity.h')
| -rw-r--r-- | include/linux/fsverity.h | 172 |
1 files changed, 84 insertions, 88 deletions
diff --git a/include/linux/fsverity.h b/include/linux/fsverity.h index 1eb7eae580be..a8f9aa75b792 100644 --- a/include/linux/fsverity.h +++ b/include/linux/fsverity.h @@ -26,9 +26,10 @@ /* Arbitrary limit to bound the kmalloc() size. Can be changed. */ #define FS_VERITY_MAX_DESCRIPTOR_SIZE 16384 +struct fsverity_info; + /* Verity operations for filesystems */ struct fsverity_operations { - /** * Begin enabling verity on the given file. * @@ -89,10 +90,6 @@ struct fsverity_operations { * * @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. @@ -102,13 +99,28 @@ struct fsverity_operations { * 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); + pgoff_t index); + + /** + * Perform readahead of a Merkle tree for the given inode. + * + * @inode: the inode + * @index: 0-based index of the first page within the Merkle tree + * @nr_pages: number of pages to be read ahead. + * + * This can be called at any time on an open verity file. It may be + * called by multiple processes concurrently, even with the same range. + * + * Optional method so that ->read_merkle_tree_page preferably finds + * cached data instead of issuing dependent I/O. + */ + void (*readahead_merkle_tree)(struct inode *inode, pgoff_t index, + unsigned long nr_pages); /** - * Write a Merkle tree block to the given inode. + * Write a Merkle tree block to the given file. * - * @inode: the inode for which the Merkle tree is being built + * @file: the file 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) @@ -118,21 +130,48 @@ struct fsverity_operations { * * Return: 0 on success, -errno on failure */ - int (*write_merkle_tree_block)(struct inode *inode, const void *buf, + int (*write_merkle_tree_block)(struct file *file, const void *buf, u64 pos, unsigned int size); }; #ifdef CONFIG_FS_VERITY +/** + * fsverity_active() - do reads from the inode need to go through fs-verity? + * @inode: inode to check + * + * This checks whether the inode's verity info has been set, and reads need + * to verify the file data. + * + * Return: true if reads need to go through fs-verity, otherwise false + */ +static inline bool fsverity_active(const struct inode *inode) +{ + if (IS_VERITY(inode)) { + /* + * This pairs with the try_cmpxchg in set_mask_bits() + * used to set the S_VERITY bit in i_flags. + */ + smp_mb(); + return true; + } + return false; +} + +struct fsverity_info *__fsverity_get_info(const struct inode *inode); +/** + * fsverity_get_info - get fsverity information for an inode + * @inode: inode to operate on. + * + * This gets the fsverity_info for @inode if it exists. Safe to call without + * knowin that a fsverity_info exist for @inode, including on file systems that + * do not support fsverity. + */ 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); + if (!fsverity_active(inode)) + return NULL; + return __fsverity_get_info(inode); } /* enable.c */ @@ -149,20 +188,6 @@ int fsverity_get_digest(struct inode *inode, /* 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 */ @@ -170,12 +195,20 @@ 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_readahead(struct fsverity_info *vi, pgoff_t index, + unsigned long nr_pages); +bool fsverity_verify_blocks(struct fsverity_info *vi, struct folio *folio, + size_t len, size_t offset); +void fsverity_verify_bio(struct fsverity_info *vi, struct bio *bio); void fsverity_enqueue_verify_work(struct work_struct *work); #else /* !CONFIG_FS_VERITY */ +static inline bool fsverity_active(const struct inode *inode) +{ + return false; +} + static inline struct fsverity_info *fsverity_get_info(const struct inode *inode) { return NULL; @@ -214,16 +247,6 @@ 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, @@ -234,14 +257,21 @@ static inline int fsverity_ioctl_read_metadata(struct file *filp, /* verify.c */ -static inline bool fsverity_verify_blocks(struct folio *folio, size_t len, +static inline void fsverity_readahead(struct fsverity_info *vi, pgoff_t index, + unsigned long nr_pages) +{ +} + +static inline bool fsverity_verify_blocks(struct fsverity_info *vi, + struct folio *folio, size_t len, size_t offset) { WARN_ON_ONCE(1); return false; } -static inline void fsverity_verify_bio(struct bio *bio) +static inline void fsverity_verify_bio(struct fsverity_info *vi, + struct bio *bio) { WARN_ON_ONCE(1); } @@ -253,32 +283,10 @@ static inline void fsverity_enqueue_verify_work(struct work_struct *work) #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) +static inline bool fsverity_verify_folio(struct fsverity_info *vi, + struct folio *folio) { - return fsverity_get_info(inode) != NULL; + return fsverity_verify_blocks(vi, folio, folio_size(folio), 0); } /** @@ -287,7 +295,7 @@ static inline bool fsverity_active(const struct inode *inode) * @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. + * set up the inode's 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. @@ -301,22 +309,10 @@ static inline int fsverity_file_open(struct inode *inode, struct file *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; -} +void fsverity_cleanup_inode(struct inode *inode); + +struct page *generic_read_merkle_tree_page(struct inode *inode, pgoff_t index); +void generic_readahead_merkle_tree(struct inode *inode, pgoff_t index, + unsigned long nr_pages); #endif /* _LINUX_FSVERITY_H */ |