1 // SPDX-License-Identifier: GPL-2.0-or-later <<
2 /* 1 /*
3 * Squashfs - a compressed read only filesyste 2 * Squashfs - a compressed read only filesystem for Linux
4 * 3 *
5 * Copyright (c) 2010 4 * Copyright (c) 2010
6 * Phillip Lougher <phillip@squashfs.org.uk> 5 * Phillip Lougher <phillip@squashfs.org.uk>
>> 6 *
>> 7 * This program is free software; you can redistribute it and/or
>> 8 * modify it under the terms of the GNU General Public License
>> 9 * as published by the Free Software Foundation; either version 2,
>> 10 * or (at your option) any later version.
>> 11 *
>> 12 * This program is distributed in the hope that it will be useful,
>> 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
>> 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
>> 15 * GNU General Public License for more details.
>> 16 *
>> 17 * You should have received a copy of the GNU General Public License
>> 18 * along with this program; if not, write to the Free Software
>> 19 * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
7 * 20 *
8 * xattr_id.c 21 * xattr_id.c
9 */ 22 */
10 23
11 /* 24 /*
12 * This file implements code to map the 32-bit 25 * 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 26 * into the on disk location of the xattr data.
14 */ 27 */
15 28
16 #include <linux/fs.h> 29 #include <linux/fs.h>
17 #include <linux/vfs.h> 30 #include <linux/vfs.h>
18 #include <linux/slab.h> 31 #include <linux/slab.h>
19 32
20 #include "squashfs_fs.h" 33 #include "squashfs_fs.h"
21 #include "squashfs_fs_sb.h" 34 #include "squashfs_fs_sb.h"
22 #include "squashfs.h" 35 #include "squashfs.h"
23 #include "xattr.h" 36 #include "xattr.h"
24 37
25 /* 38 /*
26 * Map xattr id using the xattr id look up tab 39 * Map xattr id using the xattr id look up table
27 */ 40 */
28 int squashfs_xattr_lookup(struct super_block * 41 int squashfs_xattr_lookup(struct super_block *sb, unsigned int index,
29 int *count, unsigned int *size 42 int *count, unsigned int *size, unsigned long long *xattr)
30 { 43 {
31 struct squashfs_sb_info *msblk = sb->s 44 struct squashfs_sb_info *msblk = sb->s_fs_info;
32 int block = SQUASHFS_XATTR_BLOCK(index 45 int block = SQUASHFS_XATTR_BLOCK(index);
33 int offset = SQUASHFS_XATTR_BLOCK_OFFS 46 int offset = SQUASHFS_XATTR_BLOCK_OFFSET(index);
34 u64 start_block; 47 u64 start_block;
35 struct squashfs_xattr_id id; 48 struct squashfs_xattr_id id;
36 int err; 49 int err;
37 50
38 if (index >= msblk->xattr_ids) 51 if (index >= msblk->xattr_ids)
39 return -EINVAL; 52 return -EINVAL;
40 53
41 start_block = le64_to_cpu(msblk->xattr 54 start_block = le64_to_cpu(msblk->xattr_id_table[block]);
42 55
43 err = squashfs_read_metadata(sb, &id, 56 err = squashfs_read_metadata(sb, &id, &start_block, &offset,
44 57 sizeof(id));
45 if (err < 0) 58 if (err < 0)
46 return err; 59 return err;
47 60
48 *xattr = le64_to_cpu(id.xattr); 61 *xattr = le64_to_cpu(id.xattr);
49 *size = le32_to_cpu(id.size); 62 *size = le32_to_cpu(id.size);
50 *count = le32_to_cpu(id.count); 63 *count = le32_to_cpu(id.count);
51 return 0; 64 return 0;
52 } 65 }
53 66
54 67
55 /* 68 /*
56 * Read uncompressed xattr id lookup table ind 69 * Read uncompressed xattr id lookup table indexes from disk into memory
57 */ 70 */
58 __le64 *squashfs_read_xattr_id_table(struct su 71 __le64 *squashfs_read_xattr_id_table(struct super_block *sb, u64 table_start,
59 u64 *xattr_table_start, unsign 72 u64 *xattr_table_start, unsigned int *xattr_ids)
60 { 73 {
61 struct squashfs_sb_info *msblk = sb->s 74 struct squashfs_sb_info *msblk = sb->s_fs_info;
62 unsigned int len, indexes; 75 unsigned int len, indexes;
63 struct squashfs_xattr_id_table *id_tab 76 struct squashfs_xattr_id_table *id_table;
64 __le64 *table; 77 __le64 *table;
65 u64 start, end; 78 u64 start, end;
66 int n; 79 int n;
67 80
68 id_table = squashfs_read_table(sb, tab 81 id_table = squashfs_read_table(sb, table_start, sizeof(*id_table));
69 if (IS_ERR(id_table)) 82 if (IS_ERR(id_table))
70 return (__le64 *) id_table; 83 return (__le64 *) id_table;
71 84
72 *xattr_table_start = le64_to_cpu(id_ta 85 *xattr_table_start = le64_to_cpu(id_table->xattr_table_start);
73 *xattr_ids = le32_to_cpu(id_table->xat 86 *xattr_ids = le32_to_cpu(id_table->xattr_ids);
74 kfree(id_table); 87 kfree(id_table);
75 88
76 /* Sanity check values */ 89 /* Sanity check values */
77 90
78 /* there is always at least one xattr 91 /* there is always at least one xattr id */
79 if (*xattr_ids == 0) 92 if (*xattr_ids == 0)
80 return ERR_PTR(-EINVAL); 93 return ERR_PTR(-EINVAL);
81 94
82 len = SQUASHFS_XATTR_BLOCK_BYTES(*xatt 95 len = SQUASHFS_XATTR_BLOCK_BYTES(*xattr_ids);
83 indexes = SQUASHFS_XATTR_BLOCKS(*xattr 96 indexes = SQUASHFS_XATTR_BLOCKS(*xattr_ids);
84 97
85 /* 98 /*
86 * The computed size of the index tabl 99 * The computed size of the index table (len bytes) should exactly
87 * match the table start and end point 100 * match the table start and end points
88 */ 101 */
89 start = table_start + sizeof(*id_table 102 start = table_start + sizeof(*id_table);
90 end = msblk->bytes_used; 103 end = msblk->bytes_used;
91 104
92 if (len != (end - start)) 105 if (len != (end - start))
93 return ERR_PTR(-EINVAL); 106 return ERR_PTR(-EINVAL);
94 107
95 table = squashfs_read_table(sb, start, 108 table = squashfs_read_table(sb, start, len);
96 if (IS_ERR(table)) 109 if (IS_ERR(table))
97 return table; 110 return table;
98 111
99 /* table[0], table[1], ... table[index 112 /* table[0], table[1], ... table[indexes - 1] store the locations
100 * of the compressed xattr id blocks. 113 * of the compressed xattr id blocks. Each entry should be less than
101 * the next (i.e. table[0] < table[1]) 114 * the next (i.e. table[0] < table[1]), and the difference between them
102 * should be SQUASHFS_METADATA_SIZE or 115 * should be SQUASHFS_METADATA_SIZE or less. table[indexes - 1]
103 * should be less than table_start, an 116 * should be less than table_start, and again the difference
104 * shouls be SQUASHFS_METADATA_SIZE or 117 * shouls be SQUASHFS_METADATA_SIZE or less.
105 * 118 *
106 * Finally xattr_table_start should be 119 * Finally xattr_table_start should be less than table[0].
107 */ 120 */
108 for (n = 0; n < (indexes - 1); n++) { 121 for (n = 0; n < (indexes - 1); n++) {
109 start = le64_to_cpu(table[n]); 122 start = le64_to_cpu(table[n]);
110 end = le64_to_cpu(table[n + 1] 123 end = le64_to_cpu(table[n + 1]);
111 124
112 if (start >= end || (end - sta 125 if (start >= end || (end - start) >
113 (SQUASHFS_META 126 (SQUASHFS_METADATA_SIZE + SQUASHFS_BLOCK_OFFSET)) {
114 kfree(table); 127 kfree(table);
115 return ERR_PTR(-EINVAL 128 return ERR_PTR(-EINVAL);
116 } 129 }
117 } 130 }
118 131
119 start = le64_to_cpu(table[indexes - 1] 132 start = le64_to_cpu(table[indexes - 1]);
120 if (start >= table_start || (table_sta 133 if (start >= table_start || (table_start - start) >
121 (SQUASHFS_META 134 (SQUASHFS_METADATA_SIZE + SQUASHFS_BLOCK_OFFSET)) {
122 kfree(table); 135 kfree(table);
123 return ERR_PTR(-EINVAL); 136 return ERR_PTR(-EINVAL);
124 } 137 }
125 138
126 if (*xattr_table_start >= le64_to_cpu( 139 if (*xattr_table_start >= le64_to_cpu(table[0])) {
127 kfree(table); 140 kfree(table);
128 return ERR_PTR(-EINVAL); 141 return ERR_PTR(-EINVAL);
129 } 142 }
130 143
131 return table; 144 return table;
132 } 145 }
133 146
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