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Edit File: fsverity.h
/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ /* * fs-verity user API * * These ioctls can be used on filesystems that support fs-verity. See the * "User API" section of Documentation/filesystems/fsverity.rst. * * Copyright 2019 Google LLC */ #ifndef _LINUX_FSVERITY_H #define _LINUX_FSVERITY_H #include <linux/ioctl.h> #include <linux/types.h> #define FS_VERITY_HASH_ALG_SHA256 1 #define FS_VERITY_HASH_ALG_SHA512 2 struct fsverity_enable_arg { __u32 version; __u32 hash_algorithm; __u32 block_size; __u32 salt_size; __u64 salt_ptr; __u32 sig_size; __u32 __reserved1; __u64 sig_ptr; __u64 __reserved2[11]; }; struct fsverity_digest { __u16 digest_algorithm; __u16 digest_size; /* input/output */ __u8 digest[]; }; /* * Struct containing a file's Merkle tree properties. The fs-verity file digest * is the hash of this struct. A userspace program needs this struct only if it * needs to compute fs-verity file digests itself, e.g. in order to sign files. * It isn't needed just to enable fs-verity on a file. * * Note: when computing the file digest, 'sig_size' and 'signature' must be left * zero and empty, respectively. These fields are present only because some * filesystems reuse this struct as part of their on-disk format. */ struct fsverity_descriptor { __u8 version; /* must be 1 */ __u8 hash_algorithm; /* Merkle tree hash algorithm */ __u8 log_blocksize; /* log2 of size of data and tree blocks */ __u8 salt_size; /* size of salt in bytes; 0 if none */ __le32 __reserved_0x04; /* must be 0 */ __le64 data_size; /* size of file the Merkle tree is built over */ __u8 root_hash[64]; /* Merkle tree root hash */ __u8 salt[32]; /* salt prepended to each hashed block */ __u8 __reserved[144]; /* must be 0's */ }; /* * Format in which fs-verity file digests are signed in built-in signatures. * This is the same as 'struct fsverity_digest', except here some magic bytes * are prepended to provide some context about what is being signed in case the * same key is used for non-fsverity purposes, and here the fields have fixed * endianness. * * This struct is specific to the built-in signature verification support, which * is optional. fs-verity users may also verify signatures in userspace, in * which case userspace is responsible for deciding on what bytes are signed. * This struct may still be used, but it doesn't have to be. For example, * userspace could instead use a string like "sha256:$digest_as_hex_string". */ struct fsverity_formatted_digest { char magic[8]; /* must be "FSVerity" */ __le16 digest_algorithm; __le16 digest_size; __u8 digest[]; }; #define FS_VERITY_METADATA_TYPE_MERKLE_TREE 1 #define FS_VERITY_METADATA_TYPE_DESCRIPTOR 2 #define FS_VERITY_METADATA_TYPE_SIGNATURE 3 struct fsverity_read_metadata_arg { __u64 metadata_type; __u64 offset; __u64 length; __u64 buf_ptr; __u64 __reserved; }; #define FS_IOC_ENABLE_VERITY _IOW('f', 133, struct fsverity_enable_arg) #define FS_IOC_MEASURE_VERITY _IOWR('f', 134, struct fsverity_digest) #define FS_IOC_READ_VERITY_METADATA \ _IOWR('f', 135, struct fsverity_read_metadata_arg) #endif /* _LINUX_FSVERITY_H */