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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
15 #include <linux/seq_file.h>
16 #include <linux/vmalloc.h>
17 #include <linux/kexec.h>
20 #ifdef CONFIG_IMA_KEXEC
21 static int ima_dump_measurement_list(unsigned long *buffer_size, void **buffer,
22 unsigned long segment_size)
24 struct ima_queue_entry *qe;
26 struct ima_kexec_hdr khdr;
29 /* segment size can't change between kexec load and execute */
30 file.buf = vmalloc(segment_size);
36 file.size = segment_size;
38 file.count = sizeof(khdr); /* reserved space */
40 memset(&khdr, 0, sizeof(khdr));
42 list_for_each_entry_rcu(qe, &ima_measurements, later) {
43 if (file.count < file.size) {
45 ima_measurements_show(&file, qe);
56 * fill in reserved space with some buffer details
57 * (eg. version, buffer size, number of measurements)
59 khdr.buffer_size = file.count;
60 if (ima_canonical_fmt) {
61 khdr.version = cpu_to_le16(khdr.version);
62 khdr.count = cpu_to_le64(khdr.count);
63 khdr.buffer_size = cpu_to_le64(khdr.buffer_size);
65 memcpy(file.buf, &khdr, sizeof(khdr));
67 print_hex_dump(KERN_DEBUG, "ima dump: ", DUMP_PREFIX_NONE,
69 file.count < 100 ? file.count : 100, true);
71 *buffer_size = file.count;
80 * Called during kexec_file_load so that IMA can add a segment to the kexec
81 * image for the measurement list for the next kernel.
83 * This function assumes that kexec_mutex is held.
85 void ima_add_kexec_buffer(struct kimage *image)
87 struct kexec_buf kbuf = { .image = image, .buf_align = PAGE_SIZE,
88 .buf_min = 0, .buf_max = ULONG_MAX,
90 unsigned long binary_runtime_size;
92 /* use more understandable variable names than defined in kbuf */
93 void *kexec_buffer = NULL;
94 size_t kexec_buffer_size;
95 size_t kexec_segment_size;
99 * Reserve an extra half page of memory for additional measurements
100 * added during the kexec load.
102 binary_runtime_size = ima_get_binary_runtime_size();
103 if (binary_runtime_size >= ULONG_MAX - PAGE_SIZE)
104 kexec_segment_size = ULONG_MAX;
106 kexec_segment_size = ALIGN(ima_get_binary_runtime_size() +
107 PAGE_SIZE / 2, PAGE_SIZE);
108 if ((kexec_segment_size == ULONG_MAX) ||
109 ((kexec_segment_size >> PAGE_SHIFT) > totalram_pages() / 2)) {
110 pr_err("Binary measurement list too large.\n");
114 ima_dump_measurement_list(&kexec_buffer_size, &kexec_buffer,
117 pr_err("Not enough memory for the kexec measurement buffer.\n");
121 kbuf.buffer = kexec_buffer;
122 kbuf.bufsz = kexec_buffer_size;
123 kbuf.memsz = kexec_segment_size;
124 ret = kexec_add_buffer(&kbuf);
126 pr_err("Error passing over kexec measurement buffer.\n");
130 ret = arch_ima_add_kexec_buffer(image, kbuf.mem, kexec_segment_size);
132 pr_err("Error passing over kexec measurement buffer.\n");
136 pr_debug("kexec measurement buffer for the loaded kernel at 0x%lx.\n",
139 #endif /* IMA_KEXEC */
142 * Restore the measurement list from the previous kernel.
144 void ima_load_kexec_buffer(void)
146 void *kexec_buffer = NULL;
147 size_t kexec_buffer_size = 0;
150 rc = ima_get_kexec_buffer(&kexec_buffer, &kexec_buffer_size);
153 rc = ima_restore_measurement_list(kexec_buffer_size,
156 pr_err("Failed to restore the measurement list: %d\n",
159 ima_free_kexec_buffer();
162 pr_debug("Restoring the measurement list not supported\n");
165 pr_debug("No measurement list to restore\n");
168 pr_debug("Error restoring the measurement list: %d\n", rc);