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
|
/*
* Copyright (C) 2016 IBM Corporation
*
* Authors:
* Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
* Mimi Zohar <zohar@linux.vnet.ibm.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/seq_file.h>
#include <linux/vmalloc.h>
#include <linux/kexec.h>
#include "ima.h"
#ifdef CONFIG_IMA_KEXEC
static int ima_dump_measurement_list(unsigned long *buffer_size, void **buffer,
unsigned long segment_size)
{
struct ima_queue_entry *qe;
struct seq_file file;
struct ima_kexec_hdr khdr;
int ret = 0;
/* segment size can't change between kexec load and execute */
file.buf = vmalloc(segment_size);
if (!file.buf) {
ret = -ENOMEM;
goto out;
}
file.size = segment_size;
file.read_pos = 0;
file.count = sizeof(khdr); /* reserved space */
memset(&khdr, 0, sizeof(khdr));
khdr.version = 1;
list_for_each_entry_rcu(qe, &ima_measurements, later) {
if (file.count < file.size) {
khdr.count++;
ima_measurements_show(&file, qe);
} else {
ret = -EINVAL;
break;
}
}
if (ret < 0)
goto out;
/*
* fill in reserved space with some buffer details
* (eg. version, buffer size, number of measurements)
*/
khdr.buffer_size = file.count;
if (ima_canonical_fmt) {
khdr.version = cpu_to_le16(khdr.version);
khdr.count = cpu_to_le64(khdr.count);
khdr.buffer_size = cpu_to_le64(khdr.buffer_size);
}
memcpy(file.buf, &khdr, sizeof(khdr));
print_hex_dump(KERN_DEBUG, "ima dump: ", DUMP_PREFIX_NONE,
16, 1, file.buf,
file.count < 100 ? file.count : 100, true);
*buffer_size = file.count;
*buffer = file.buf;
out:
if (ret == -EINVAL)
vfree(file.buf);
return ret;
}
/*
* Called during kexec_file_load so that IMA can add a segment to the kexec
* image for the measurement list for the next kernel.
*
* This function assumes that kexec_mutex is held.
*/
void ima_add_kexec_buffer(struct kimage *image)
{
struct kexec_buf kbuf = { .image = image, .buf_align = PAGE_SIZE,
.buf_min = 0, .buf_max = ULONG_MAX,
.top_down = true };
unsigned long binary_runtime_size;
/* use more understandable variable names than defined in kbuf */
void *kexec_buffer = NULL;
size_t kexec_buffer_size;
size_t kexec_segment_size;
int ret;
/*
* Reserve an extra half page of memory for additional measurements
* added during the kexec load.
*/
binary_runtime_size = ima_get_binary_runtime_size();
if (binary_runtime_size >= ULONG_MAX - PAGE_SIZE)
kexec_segment_size = ULONG_MAX;
else
kexec_segment_size = ALIGN(ima_get_binary_runtime_size() +
PAGE_SIZE / 2, PAGE_SIZE);
if ((kexec_segment_size == ULONG_MAX) ||
((kexec_segment_size >> PAGE_SHIFT) > totalram_pages() / 2)) {
pr_err("Binary measurement list too large.\n");
return;
}
ima_dump_measurement_list(&kexec_buffer_size, &kexec_buffer,
kexec_segment_size);
if (!kexec_buffer) {
pr_err("Not enough memory for the kexec measurement buffer.\n");
return;
}
kbuf.buffer = kexec_buffer;
kbuf.bufsz = kexec_buffer_size;
kbuf.memsz = kexec_segment_size;
ret = kexec_add_buffer(&kbuf);
if (ret) {
pr_err("Error passing over kexec measurement buffer.\n");
return;
}
ret = arch_ima_add_kexec_buffer(image, kbuf.mem, kexec_segment_size);
if (ret) {
pr_err("Error passing over kexec measurement buffer.\n");
return;
}
pr_debug("kexec measurement buffer for the loaded kernel at 0x%lx.\n",
kbuf.mem);
}
#endif /* IMA_KEXEC */
/*
* Restore the measurement list from the previous kernel.
*/
void ima_load_kexec_buffer(void)
{
void *kexec_buffer = NULL;
size_t kexec_buffer_size = 0;
int rc;
rc = ima_get_kexec_buffer(&kexec_buffer, &kexec_buffer_size);
switch (rc) {
case 0:
rc = ima_restore_measurement_list(kexec_buffer_size,
kexec_buffer);
if (rc != 0)
pr_err("Failed to restore the measurement list: %d\n",
rc);
ima_free_kexec_buffer();
break;
case -ENOTSUPP:
pr_debug("Restoring the measurement list not supported\n");
break;
case -ENOENT:
pr_debug("No measurement list to restore\n");
break;
default:
pr_debug("Error restoring the measurement list: %d\n", rc);
}
}
|
