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
|
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2016 IBM Corporation
*
* Authors:
* Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
*/
#include <linux/slab.h>
#include <linux/kexec.h>
#include <linux/of.h>
#include <linux/memblock.h>
#include <linux/libfdt.h>
static int get_addr_size_cells(int *addr_cells, int *size_cells)
{
struct device_node *root;
root = of_find_node_by_path("/");
if (!root)
return -EINVAL;
*addr_cells = of_n_addr_cells(root);
*size_cells = of_n_size_cells(root);
of_node_put(root);
return 0;
}
static int do_get_kexec_buffer(const void *prop, int len, unsigned long *addr,
size_t *size)
{
int ret, addr_cells, size_cells;
ret = get_addr_size_cells(&addr_cells, &size_cells);
if (ret)
return ret;
if (len < 4 * (addr_cells + size_cells))
return -ENOENT;
*addr = of_read_number(prop, addr_cells);
*size = of_read_number(prop + 4 * addr_cells, size_cells);
return 0;
}
/**
* ima_get_kexec_buffer - get IMA buffer from the previous kernel
* @addr: On successful return, set to point to the buffer contents.
* @size: On successful return, set to the buffer size.
*
* Return: 0 on success, negative errno on error.
*/
int ima_get_kexec_buffer(void **addr, size_t *size)
{
int ret, len;
unsigned long tmp_addr;
size_t tmp_size;
const void *prop;
prop = of_get_property(of_chosen, "linux,ima-kexec-buffer", &len);
if (!prop)
return -ENOENT;
ret = do_get_kexec_buffer(prop, len, &tmp_addr, &tmp_size);
if (ret)
return ret;
*addr = __va(tmp_addr);
*size = tmp_size;
return 0;
}
/**
* ima_free_kexec_buffer - free memory used by the IMA buffer
*/
int ima_free_kexec_buffer(void)
{
int ret;
unsigned long addr;
size_t size;
struct property *prop;
prop = of_find_property(of_chosen, "linux,ima-kexec-buffer", NULL);
if (!prop)
return -ENOENT;
ret = do_get_kexec_buffer(prop->value, prop->length, &addr, &size);
if (ret)
return ret;
ret = of_remove_property(of_chosen, prop);
if (ret)
return ret;
return memblock_free(addr, size);
}
/**
* remove_ima_buffer - remove the IMA buffer property and reservation from @fdt
*
* The IMA measurement buffer is of no use to a subsequent kernel, so we always
* remove it from the device tree.
*/
void remove_ima_buffer(void *fdt, int chosen_node)
{
int ret, len;
unsigned long addr;
size_t size;
const void *prop;
prop = fdt_getprop(fdt, chosen_node, "linux,ima-kexec-buffer", &len);
if (!prop)
return;
ret = do_get_kexec_buffer(prop, len, &addr, &size);
fdt_delprop(fdt, chosen_node, "linux,ima-kexec-buffer");
if (ret)
return;
ret = delete_fdt_mem_rsv(fdt, addr, size);
if (!ret)
pr_debug("Removed old IMA buffer reservation.\n");
}
#ifdef CONFIG_IMA_KEXEC
/**
* arch_ima_add_kexec_buffer - do arch-specific steps to add the IMA buffer
*
* Architectures should use this function to pass on the IMA buffer
* information to the next kernel.
*
* Return: 0 on success, negative errno on error.
*/
int arch_ima_add_kexec_buffer(struct kimage *image, unsigned long load_addr,
size_t size)
{
image->arch.ima_buffer_addr = load_addr;
image->arch.ima_buffer_size = size;
return 0;
}
static int write_number(void *p, u64 value, int cells)
{
if (cells == 1) {
u32 tmp;
if (value > U32_MAX)
return -EINVAL;
tmp = cpu_to_be32(value);
memcpy(p, &tmp, sizeof(tmp));
} else if (cells == 2) {
u64 tmp;
tmp = cpu_to_be64(value);
memcpy(p, &tmp, sizeof(tmp));
} else
return -EINVAL;
return 0;
}
/**
* setup_ima_buffer - add IMA buffer information to the fdt
* @image: kexec image being loaded.
* @fdt: Flattened device tree for the next kernel.
* @chosen_node: Offset to the chosen node.
*
* Return: 0 on success, or negative errno on error.
*/
int setup_ima_buffer(const struct kimage *image, void *fdt, int chosen_node)
{
int ret, addr_cells, size_cells, entry_size;
u8 value[16];
remove_ima_buffer(fdt, chosen_node);
if (!image->arch.ima_buffer_size)
return 0;
ret = get_addr_size_cells(&addr_cells, &size_cells);
if (ret)
return ret;
entry_size = 4 * (addr_cells + size_cells);
if (entry_size > sizeof(value))
return -EINVAL;
ret = write_number(value, image->arch.ima_buffer_addr, addr_cells);
if (ret)
return ret;
ret = write_number(value + 4 * addr_cells, image->arch.ima_buffer_size,
size_cells);
if (ret)
return ret;
ret = fdt_setprop(fdt, chosen_node, "linux,ima-kexec-buffer", value,
entry_size);
if (ret < 0)
return -EINVAL;
ret = fdt_add_mem_rsv(fdt, image->arch.ima_buffer_addr,
image->arch.ima_buffer_size);
if (ret)
return -EINVAL;
pr_debug("IMA buffer at 0x%llx, size = 0x%zx\n",
image->arch.ima_buffer_addr, image->arch.ima_buffer_size);
return 0;
}
#endif /* CONFIG_IMA_KEXEC */
|
