2 * Copyright (C) 2016 IBM Corporation
5 * Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
6 * Mimi Zohar <zohar@linux.vnet.ibm.com>
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
13 #include <linux/seq_file.h>
14 #include <linux/vmalloc.h>
15 #include <linux/kexec.h>
18 #ifdef CONFIG_IMA_KEXEC
19 static int ima_dump_measurement_list(unsigned long *buffer_size, void **buffer,
20 unsigned long segment_size)
22 struct ima_queue_entry *qe;
24 struct ima_kexec_hdr khdr = {
25 .version = 1, .buffer_size = 0, .count = 0};
28 /* segment size can't change between kexec load and execute */
29 file.buf = vmalloc(segment_size);
35 file.size = segment_size;
37 file.count = sizeof(khdr); /* reserved space */
39 list_for_each_entry_rcu(qe, &ima_measurements, later) {
40 if (file.count < file.size) {
42 ima_measurements_show(&file, qe);
53 * fill in reserved space with some buffer details
54 * (eg. version, buffer size, number of measurements)
56 khdr.buffer_size = file.count;
57 memcpy(file.buf, &khdr, sizeof(khdr));
58 print_hex_dump(KERN_DEBUG, "ima dump: ", DUMP_PREFIX_NONE,
60 file.count < 100 ? file.count : 100, true);
62 *buffer_size = file.count;
71 * Called during kexec_file_load so that IMA can add a segment to the kexec
72 * image for the measurement list for the next kernel.
74 * This function assumes that kexec_mutex is held.
76 void ima_add_kexec_buffer(struct kimage *image)
78 struct kexec_buf kbuf = { .image = image, .buf_align = PAGE_SIZE,
79 .buf_min = 0, .buf_max = ULONG_MAX,
81 unsigned long binary_runtime_size;
83 /* use more understandable variable names than defined in kbuf */
84 void *kexec_buffer = NULL;
85 size_t kexec_buffer_size;
86 size_t kexec_segment_size;
90 * Reserve an extra half page of memory for additional measurements
91 * added during the kexec load.
93 binary_runtime_size = ima_get_binary_runtime_size();
94 if (binary_runtime_size >= ULONG_MAX - PAGE_SIZE)
95 kexec_segment_size = ULONG_MAX;
97 kexec_segment_size = ALIGN(ima_get_binary_runtime_size() +
98 PAGE_SIZE / 2, PAGE_SIZE);
99 if ((kexec_segment_size == ULONG_MAX) ||
100 ((kexec_segment_size >> PAGE_SHIFT) > totalram_pages / 2)) {
101 pr_err("Binary measurement list too large.\n");
105 ima_dump_measurement_list(&kexec_buffer_size, &kexec_buffer,
108 pr_err("Not enough memory for the kexec measurement buffer.\n");
112 kbuf.buffer = kexec_buffer;
113 kbuf.bufsz = kexec_buffer_size;
114 kbuf.memsz = kexec_segment_size;
115 ret = kexec_add_buffer(&kbuf);
117 pr_err("Error passing over kexec measurement buffer.\n");
121 ret = arch_ima_add_kexec_buffer(image, kbuf.mem, kexec_segment_size);
123 pr_err("Error passing over kexec measurement buffer.\n");
127 pr_debug("kexec measurement buffer for the loaded kernel at 0x%lx.\n",
130 #endif /* IMA_KEXEC */
133 * Restore the measurement list from the previous kernel.
135 void ima_load_kexec_buffer(void)
137 void *kexec_buffer = NULL;
138 size_t kexec_buffer_size = 0;
141 rc = ima_get_kexec_buffer(&kexec_buffer, &kexec_buffer_size);
144 rc = ima_restore_measurement_list(kexec_buffer_size,
147 pr_err("Failed to restore the measurement list: %d\n",
150 ima_free_kexec_buffer();
153 pr_debug("Restoring the measurement list not supported\n");
156 pr_debug("No measurement list to restore\n");
159 pr_debug("Error restoring the measurement list: %d\n", rc);