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Diffstat (limited to 'include/uapi/linux/fsverity.h')
| -rw-r--r-- | include/uapi/linux/fsverity.h | 103 |
1 files changed, 103 insertions, 0 deletions
diff --git a/include/uapi/linux/fsverity.h b/include/uapi/linux/fsverity.h new file mode 100644 index 000000000..15384e22e --- /dev/null +++ b/include/uapi/linux/fsverity.h @@ -0,0 +1,103 @@ +/* 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 _UAPI_LINUX_FSVERITY_H +#define _UAPI_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 */ +#ifdef __KERNEL__ + __le32 sig_size; +#else + __le32 __reserved_0x04; /* must be 0 */ +#endif + __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 */ +#ifdef __KERNEL__ + __u8 signature[]; +#endif +}; + +/* + * 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 /* _UAPI_LINUX_FSVERITY_H */ |