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1 | /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ |
2 | /* | |
3 | * fs-verity user API | |
4 | * | |
5 | * These ioctls can be used on filesystems that support fs-verity. See the | |
6 | * "User API" section of Documentation/filesystems/fsverity.rst. | |
7 | * | |
8 | * Copyright 2019 Google LLC | |
9 | */ | |
10 | #ifndef _UAPI_LINUX_FSVERITY_H | |
11 | #define _UAPI_LINUX_FSVERITY_H | |
12 | ||
13 | #include <linux/ioctl.h> | |
14 | #include <linux/types.h> | |
15 | ||
16 | #define FS_VERITY_HASH_ALG_SHA256 1 | |
add890c9 | 17 | #define FS_VERITY_HASH_ALG_SHA512 2 |
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18 | |
19 | struct fsverity_enable_arg { | |
20 | __u32 version; | |
21 | __u32 hash_algorithm; | |
22 | __u32 block_size; | |
23 | __u32 salt_size; | |
24 | __u64 salt_ptr; | |
25 | __u32 sig_size; | |
26 | __u32 __reserved1; | |
27 | __u64 sig_ptr; | |
28 | __u64 __reserved2[11]; | |
29 | }; | |
30 | ||
31 | struct fsverity_digest { | |
32 | __u16 digest_algorithm; | |
33 | __u16 digest_size; /* input/output */ | |
34 | __u8 digest[]; | |
35 | }; | |
36 | ||
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37 | /* |
38 | * Struct containing a file's Merkle tree properties. The fs-verity file digest | |
39 | * is the hash of this struct. A userspace program needs this struct only if it | |
40 | * needs to compute fs-verity file digests itself, e.g. in order to sign files. | |
41 | * It isn't needed just to enable fs-verity on a file. | |
42 | * | |
43 | * Note: when computing the file digest, 'sig_size' and 'signature' must be left | |
44 | * zero and empty, respectively. These fields are present only because some | |
45 | * filesystems reuse this struct as part of their on-disk format. | |
46 | */ | |
47 | struct fsverity_descriptor { | |
48 | __u8 version; /* must be 1 */ | |
49 | __u8 hash_algorithm; /* Merkle tree hash algorithm */ | |
50 | __u8 log_blocksize; /* log2 of size of data and tree blocks */ | |
51 | __u8 salt_size; /* size of salt in bytes; 0 if none */ | |
52 | #ifdef __KERNEL__ | |
53 | __le32 sig_size; | |
54 | #else | |
55 | __le32 __reserved_0x04; /* must be 0 */ | |
56 | #endif | |
57 | __le64 data_size; /* size of file the Merkle tree is built over */ | |
58 | __u8 root_hash[64]; /* Merkle tree root hash */ | |
59 | __u8 salt[32]; /* salt prepended to each hashed block */ | |
60 | __u8 __reserved[144]; /* must be 0's */ | |
61 | #ifdef __KERNEL__ | |
62 | __u8 signature[]; | |
63 | #endif | |
64 | }; | |
65 | ||
66 | /* | |
67 | * Format in which fs-verity file digests are signed in built-in signatures. | |
68 | * This is the same as 'struct fsverity_digest', except here some magic bytes | |
69 | * are prepended to provide some context about what is being signed in case the | |
70 | * same key is used for non-fsverity purposes, and here the fields have fixed | |
71 | * endianness. | |
72 | * | |
73 | * This struct is specific to the built-in signature verification support, which | |
74 | * is optional. fs-verity users may also verify signatures in userspace, in | |
75 | * which case userspace is responsible for deciding on what bytes are signed. | |
76 | * This struct may still be used, but it doesn't have to be. For example, | |
77 | * userspace could instead use a string like "sha256:$digest_as_hex_string". | |
78 | */ | |
79 | struct fsverity_formatted_digest { | |
80 | char magic[8]; /* must be "FSVerity" */ | |
81 | __le16 digest_algorithm; | |
82 | __le16 digest_size; | |
83 | __u8 digest[]; | |
84 | }; | |
85 | ||
622699cf | 86 | #define FS_VERITY_METADATA_TYPE_MERKLE_TREE 1 |
947191ac | 87 | #define FS_VERITY_METADATA_TYPE_DESCRIPTOR 2 |
07c99001 | 88 | #define FS_VERITY_METADATA_TYPE_SIGNATURE 3 |
622699cf | 89 | |
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90 | struct fsverity_read_metadata_arg { |
91 | __u64 metadata_type; | |
92 | __u64 offset; | |
93 | __u64 length; | |
94 | __u64 buf_ptr; | |
95 | __u64 __reserved; | |
96 | }; | |
97 | ||
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98 | #define FS_IOC_ENABLE_VERITY _IOW('f', 133, struct fsverity_enable_arg) |
99 | #define FS_IOC_MEASURE_VERITY _IOWR('f', 134, struct fsverity_digest) | |
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100 | #define FS_IOC_READ_VERITY_METADATA \ |
101 | _IOWR('f', 135, struct fsverity_read_metadata_arg) | |
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102 | |
103 | #endif /* _UAPI_LINUX_FSVERITY_H */ |