1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
|
/*
* Copyright (C) 2022 Ernesto A. Fernández <ernesto@corellium.com>
*/
#include <assert.h>
#include <stdlib.h>
#include <string.h>
#include <apfs/raw.h>
#include <apfs/types.h>
#include "apfsck.h"
#include "htable.h"
#include "key.h"
#include "snapshot.h"
#include "super.h"
/**
* free_snap - Free a snapshot structure after some final checks
* @entry: the entry to free
*/
static void free_snap(struct htable_entry *entry)
{
struct snapshot *snap = (struct snapshot *)entry;
if (!snap->sn_name_seen || !snap->sn_meta_seen)
report("Snapshot", "missing metadata entry.");
if (!snap->sn_omap_seen)
report("Snapshot", "missing omap entry.");
free(entry);
}
/**
* free_snap_table - Free the snapshot hash table and all its entries
* @table: table to free
*/
void free_snap_table(struct htable_entry **table)
{
free_htable(table, free_snap);
}
/**
* get_snapshot - Find or create a snapshot structure in the snapshot hash table
* @xid: transaction id for the snapshot
*
* Returns the snapshot structure, after creating it if necessary.
*/
struct snapshot *get_snapshot(u64 xid)
{
struct htable_entry *entry;
entry = get_htable_entry(xid, sizeof(struct snapshot), vsb->v_snap_table);
return (struct snapshot *)entry;
}
/**
* parse_snap_name_record - Parse and check a snapshot name record value
* @key: pointer to the raw key
* @val: pointer to the raw value
* @len: length of the raw value
*
* Internal consistency of @key must be checked before calling this function.
*/
static void parse_snap_name_record(struct apfs_snap_name_key *key, struct apfs_snap_name_val *val, int len)
{
struct snapshot *snap = NULL;
if (len != sizeof(*val))
report("Snapshot name record", "wrong length for value.");
snap = get_snapshot(le64_to_cpu(val->snap_xid));
if (snap->sn_name_seen)
report("Snapshot tree", "snap with two name records.");
snap->sn_name_seen = true;
if (!snap->sn_meta_seen || !snap->sn_meta_name)
report("Snapshot tree", "missing a metadata record.");
if (strcmp((char *)key->name, snap->sn_meta_name) != 0)
report("Snapshot tree", "inconsistent names for snapshot.");
}
/**
* check_snapshot - Check a whole snapshot
* @xid: transaction for the snapshot
* @vol_bno: block number for the snapshot volume superblock
* @extentref_bno: block number for the snapshot's extentref tree
*/
static void check_snapshot(u64 xid, u64 vol_bno, u64 extentref_bno)
{
struct volume_superblock *latest_vsb = vsb;
u64 latest_xid = sb->s_xid;
vsb = NULL;
sb->s_xid = xid;
vsb = alloc_volume_super(true);
/* The list of extref trees is shared by all transactions */
vsb->v_snap_extrefs = latest_vsb->v_snap_extrefs;
vsb->v_snap_count = latest_vsb->v_snap_count;
vsb->v_raw = read_object(vol_bno, NULL, &vsb->v_obj);
read_volume_super(latest_vsb->v_index, vsb, &vsb->v_obj);
if (vsb->v_extref_oid != 0)
report("Snapshot volume superblock", "has extentref tree.");
vsb->v_extref_oid = extentref_bno;
if (vsb->v_omap_oid != 0)
report("Snapshot volume superblock", "has object map.");
vsb->v_omap = latest_vsb->v_omap;
vsb->v_omap_table = latest_vsb->v_omap_table;
omap_htable_clear_seen_for_snap(latest_vsb->v_omap_table);
vsb->v_snap_max_xid = latest_vsb->v_snap_max_xid;
if (vsb->v_snap_meta_oid != 0)
report("Snapshot volume superblock", "has snapshot tree.");
check_volume_super();
/* Go back to the latest transaction */
sb->s_xid = latest_xid;
latest_vsb->v_snap_extrefs = vsb->v_snap_extrefs;
latest_vsb->v_block_count += vsb->v_block_count;
vsb = latest_vsb; /* TODO: don't leak */
}
/**
* parse_snap_metadata_record - Parse and check a snapshot metadata record value
* @key: pointer to the raw key
* @val: pointer to the raw value
* @len: length of the raw value
*
* Internal consistency of @key must be checked before calling this function.
*/
static void parse_snap_metadata_record(struct apfs_snap_metadata_key *key, struct apfs_snap_metadata_val *val, int len)
{
struct snapshot *snap = NULL;
u64 snap_xid;
int namelen;
if (len < sizeof(*val) + 1)
report("Snapshot metadata record", "value is too small.");
if (*((char *)val + len - 1) != 0)
report("Snapshot metadata record", "name lacks NULL-termination.");
namelen = le16_to_cpu(val->name_len);
if (strlen((char *)val->name) + 1 != namelen)
report("Snapshot metadata record", "wrong name length.");
if (len != sizeof(*val) + namelen)
report("Snapshot metadata record", "size of value doesn't match name length.");
snap_xid = cat_cnid(&key->hdr);
snap = get_snapshot(snap_xid);
if (snap->sn_meta_seen)
report("Snapshot tree", "snap with two metadata records.");
snap->sn_meta_seen = true;
snap->sn_meta_name = calloc(1, namelen);
if (!snap->sn_meta_name)
system_error();
strcpy(snap->sn_meta_name, (char *)val->name);
if (le32_to_cpu(val->extentref_tree_type) != (APFS_OBJ_PHYSICAL | APFS_OBJECT_TYPE_BTREE))
report("Snapshot metadata", "wrong type for extentref tree.");
if (val->flags)
report_unknown("Snapshot flags");
check_snapshot(snap_xid, le64_to_cpu(val->sblock_oid), le64_to_cpu(val->extentref_tree_oid));
++vsb->v_snap_count;
}
/**
* parse_snap_record - Parse and check a snapshot tree record value
* @key: pointer to the raw key
* @val: pointer to the raw value
* @len: length of the raw value
*
* Internal consistency of @key must be checked before calling this function.
*/
void parse_snap_record(void *key, void *val, int len)
{
switch (cat_type(key)) {
case APFS_TYPE_SNAP_METADATA:
return parse_snap_metadata_record(key, val, len);
case APFS_TYPE_SNAP_NAME:
return parse_snap_name_record(key, val, len);
default:
report(NULL, "Bug!");
}
}
/**
* parse_omap_snap_record - Parse and check an omap snapshot tree record value
* @key: pointer to the raw key
* @val: pointer to the raw value
* @len: length of the raw value
*
* Internal consistency of @key must be checked before calling this function.
*/
void parse_omap_snap_record(__le64 *key, struct apfs_omap_snapshot *val, int len)
{
struct snapshot *snapshot = NULL;
u64 snap_xid;
/*
* These keys and values must be aligned to eight bytes.
* TODO: add the same check to the free queue?
*/
if ((u64)key & 7 || (u64)val & 7)
report("Omap snapshot record", "bad alignment for key or value.");
if (len != sizeof(*val))
report("Omap snapshot record", "value is too small.");
snap_xid = le64_to_cpu(*key);
if (snap_xid == 0)
report("Omap snapshot record", "xid is zero.");
if (snap_xid >= sb->s_xid)
report("Omap snapshot record", "xid is in the future.");
if (snap_xid >= vsb->v_snap_max_xid)
vsb->v_snap_max_xid = snap_xid;
snapshot = get_snapshot(snap_xid);
snapshot->sn_omap_seen = true;
if (val->oms_flags)
report_unknown("Deleted or reverted snapshot");
if (val->oms_pad)
report("Omap snapshot record", "padding should be zeroes.");
if (val->oms_oid)
report("Omap snapshot record", "oid should be zero.");
}
|
