Commit | Line | Data |
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68252eb5 | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
4b5397dc PL |
2 | /* |
3 | * Squashfs - a compressed read only filesystem for Linux | |
4 | * | |
5 | * Copyright (c) 2010 | |
d7f2ff67 | 6 | * Phillip Lougher <phillip@squashfs.org.uk> |
4b5397dc | 7 | * |
4b5397dc PL |
8 | * xattr_id.c |
9 | */ | |
10 | ||
11 | /* | |
12 | * This file implements code to map the 32-bit xattr id stored in the inode | |
13 | * into the on disk location of the xattr data. | |
14 | */ | |
15 | ||
16 | #include <linux/fs.h> | |
17 | #include <linux/vfs.h> | |
18 | #include <linux/slab.h> | |
19 | ||
20 | #include "squashfs_fs.h" | |
21 | #include "squashfs_fs_sb.h" | |
4b5397dc | 22 | #include "squashfs.h" |
5f3b321d | 23 | #include "xattr.h" |
4b5397dc PL |
24 | |
25 | /* | |
26 | * Map xattr id using the xattr id look up table | |
27 | */ | |
28 | int squashfs_xattr_lookup(struct super_block *sb, unsigned int index, | |
aa5b1894 | 29 | int *count, unsigned int *size, unsigned long long *xattr) |
4b5397dc PL |
30 | { |
31 | struct squashfs_sb_info *msblk = sb->s_fs_info; | |
32 | int block = SQUASHFS_XATTR_BLOCK(index); | |
33 | int offset = SQUASHFS_XATTR_BLOCK_OFFSET(index); | |
506220d2 | 34 | u64 start_block; |
4b5397dc PL |
35 | struct squashfs_xattr_id id; |
36 | int err; | |
37 | ||
506220d2 PL |
38 | if (index >= msblk->xattr_ids) |
39 | return -EINVAL; | |
40 | ||
41 | start_block = le64_to_cpu(msblk->xattr_id_table[block]); | |
42 | ||
4b5397dc PL |
43 | err = squashfs_read_metadata(sb, &id, &start_block, &offset, |
44 | sizeof(id)); | |
45 | if (err < 0) | |
46 | return err; | |
47 | ||
48 | *xattr = le64_to_cpu(id.xattr); | |
49 | *size = le32_to_cpu(id.size); | |
50 | *count = le32_to_cpu(id.count); | |
51 | return 0; | |
52 | } | |
53 | ||
54 | ||
55 | /* | |
56 | * Read uncompressed xattr id lookup table indexes from disk into memory | |
57 | */ | |
506220d2 | 58 | __le64 *squashfs_read_xattr_id_table(struct super_block *sb, u64 table_start, |
f65c4bbb | 59 | u64 *xattr_table_start, unsigned int *xattr_ids) |
4b5397dc | 60 | { |
506220d2 PL |
61 | struct squashfs_sb_info *msblk = sb->s_fs_info; |
62 | unsigned int len, indexes; | |
82de647e | 63 | struct squashfs_xattr_id_table *id_table; |
506220d2 PL |
64 | __le64 *table; |
65 | u64 start, end; | |
66 | int n; | |
82de647e | 67 | |
506220d2 | 68 | id_table = squashfs_read_table(sb, table_start, sizeof(*id_table)); |
82de647e PL |
69 | if (IS_ERR(id_table)) |
70 | return (__le64 *) id_table; | |
4b5397dc | 71 | |
82de647e PL |
72 | *xattr_table_start = le64_to_cpu(id_table->xattr_table_start); |
73 | *xattr_ids = le32_to_cpu(id_table->xattr_ids); | |
74 | kfree(id_table); | |
6f048645 PL |
75 | |
76 | /* Sanity check values */ | |
77 | ||
78 | /* there is always at least one xattr id */ | |
a5b21d8d | 79 | if (*xattr_ids == 0) |
6f048645 PL |
80 | return ERR_PTR(-EINVAL); |
81 | ||
506220d2 PL |
82 | len = SQUASHFS_XATTR_BLOCK_BYTES(*xattr_ids); |
83 | indexes = SQUASHFS_XATTR_BLOCKS(*xattr_ids); | |
84 | ||
85 | /* | |
86 | * The computed size of the index table (len bytes) should exactly | |
87 | * match the table start and end points | |
88 | */ | |
89 | start = table_start + sizeof(*id_table); | |
90 | end = msblk->bytes_used; | |
91 | ||
92 | if (len != (end - start)) | |
6f048645 PL |
93 | return ERR_PTR(-EINVAL); |
94 | ||
506220d2 PL |
95 | table = squashfs_read_table(sb, start, len); |
96 | if (IS_ERR(table)) | |
97 | return table; | |
98 | ||
99 | /* table[0], table[1], ... table[indexes - 1] store the locations | |
100 | * of the compressed xattr id blocks. Each entry should be less than | |
101 | * the next (i.e. table[0] < table[1]), and the difference between them | |
102 | * should be SQUASHFS_METADATA_SIZE or less. table[indexes - 1] | |
103 | * should be less than table_start, and again the difference | |
104 | * shouls be SQUASHFS_METADATA_SIZE or less. | |
105 | * | |
106 | * Finally xattr_table_start should be less than table[0]. | |
107 | */ | |
108 | for (n = 0; n < (indexes - 1); n++) { | |
109 | start = le64_to_cpu(table[n]); | |
110 | end = le64_to_cpu(table[n + 1]); | |
111 | ||
8b44ca2b PL |
112 | if (start >= end || (end - start) > |
113 | (SQUASHFS_METADATA_SIZE + SQUASHFS_BLOCK_OFFSET)) { | |
506220d2 PL |
114 | kfree(table); |
115 | return ERR_PTR(-EINVAL); | |
116 | } | |
117 | } | |
118 | ||
119 | start = le64_to_cpu(table[indexes - 1]); | |
8b44ca2b PL |
120 | if (start >= table_start || (table_start - start) > |
121 | (SQUASHFS_METADATA_SIZE + SQUASHFS_BLOCK_OFFSET)) { | |
506220d2 PL |
122 | kfree(table); |
123 | return ERR_PTR(-EINVAL); | |
124 | } | |
4b5397dc | 125 | |
506220d2 PL |
126 | if (*xattr_table_start >= le64_to_cpu(table[0])) { |
127 | kfree(table); | |
128 | return ERR_PTR(-EINVAL); | |
129 | } | |
4b5397dc | 130 | |
506220d2 | 131 | return table; |
4b5397dc | 132 | } |