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166 lines
4.0 KiB
166 lines
4.0 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* Copyright (C) 2016 IBM Corporation |
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* |
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* Authors: |
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* Thiago Jung Bauermann <[email protected]> |
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* Mimi Zohar <[email protected]> |
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*/ |
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#include <linux/seq_file.h> |
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#include <linux/vmalloc.h> |
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#include <linux/kexec.h> |
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#include <linux/of.h> |
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#include <linux/ima.h> |
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#include "ima.h" |
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#ifdef CONFIG_IMA_KEXEC |
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static int ima_dump_measurement_list(unsigned long *buffer_size, void **buffer, |
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unsigned long segment_size) |
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{ |
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struct ima_queue_entry *qe; |
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struct seq_file file; |
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struct ima_kexec_hdr khdr; |
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int ret = 0; |
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/* segment size can't change between kexec load and execute */ |
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file.buf = vmalloc(segment_size); |
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if (!file.buf) { |
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ret = -ENOMEM; |
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goto out; |
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} |
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file.size = segment_size; |
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file.read_pos = 0; |
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file.count = sizeof(khdr); /* reserved space */ |
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memset(&khdr, 0, sizeof(khdr)); |
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khdr.version = 1; |
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list_for_each_entry_rcu(qe, &ima_measurements, later) { |
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if (file.count < file.size) { |
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khdr.count++; |
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ima_measurements_show(&file, qe); |
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} else { |
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ret = -EINVAL; |
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break; |
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} |
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} |
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if (ret < 0) |
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goto out; |
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/* |
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* fill in reserved space with some buffer details |
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* (eg. version, buffer size, number of measurements) |
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*/ |
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khdr.buffer_size = file.count; |
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if (ima_canonical_fmt) { |
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khdr.version = cpu_to_le16(khdr.version); |
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khdr.count = cpu_to_le64(khdr.count); |
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khdr.buffer_size = cpu_to_le64(khdr.buffer_size); |
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} |
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memcpy(file.buf, &khdr, sizeof(khdr)); |
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print_hex_dump(KERN_DEBUG, "ima dump: ", DUMP_PREFIX_NONE, |
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16, 1, file.buf, |
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file.count < 100 ? file.count : 100, true); |
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*buffer_size = file.count; |
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*buffer = file.buf; |
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out: |
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if (ret == -EINVAL) |
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vfree(file.buf); |
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return ret; |
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} |
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/* |
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* Called during kexec_file_load so that IMA can add a segment to the kexec |
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* image for the measurement list for the next kernel. |
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* |
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* This function assumes that kexec_mutex is held. |
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*/ |
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void ima_add_kexec_buffer(struct kimage *image) |
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{ |
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struct kexec_buf kbuf = { .image = image, .buf_align = PAGE_SIZE, |
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.buf_min = 0, .buf_max = ULONG_MAX, |
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.top_down = true }; |
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unsigned long binary_runtime_size; |
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/* use more understandable variable names than defined in kbuf */ |
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void *kexec_buffer = NULL; |
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size_t kexec_buffer_size; |
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size_t kexec_segment_size; |
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int ret; |
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/* |
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* Reserve an extra half page of memory for additional measurements |
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* added during the kexec load. |
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*/ |
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binary_runtime_size = ima_get_binary_runtime_size(); |
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if (binary_runtime_size >= ULONG_MAX - PAGE_SIZE) |
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kexec_segment_size = ULONG_MAX; |
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else |
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kexec_segment_size = ALIGN(ima_get_binary_runtime_size() + |
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PAGE_SIZE / 2, PAGE_SIZE); |
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if ((kexec_segment_size == ULONG_MAX) || |
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((kexec_segment_size >> PAGE_SHIFT) > totalram_pages() / 2)) { |
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pr_err("Binary measurement list too large.\n"); |
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return; |
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} |
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ima_dump_measurement_list(&kexec_buffer_size, &kexec_buffer, |
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kexec_segment_size); |
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if (!kexec_buffer) { |
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pr_err("Not enough memory for the kexec measurement buffer.\n"); |
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return; |
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} |
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kbuf.buffer = kexec_buffer; |
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kbuf.bufsz = kexec_buffer_size; |
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kbuf.memsz = kexec_segment_size; |
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ret = kexec_add_buffer(&kbuf); |
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if (ret) { |
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pr_err("Error passing over kexec measurement buffer.\n"); |
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vfree(kexec_buffer); |
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return; |
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} |
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image->ima_buffer_addr = kbuf.mem; |
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image->ima_buffer_size = kexec_segment_size; |
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image->ima_buffer = kexec_buffer; |
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pr_debug("kexec measurement buffer for the loaded kernel at 0x%lx.\n", |
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kbuf.mem); |
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} |
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#endif /* IMA_KEXEC */ |
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/* |
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* Restore the measurement list from the previous kernel. |
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*/ |
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void ima_load_kexec_buffer(void) |
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{ |
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void *kexec_buffer = NULL; |
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size_t kexec_buffer_size = 0; |
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int rc; |
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rc = ima_get_kexec_buffer(&kexec_buffer, &kexec_buffer_size); |
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switch (rc) { |
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case 0: |
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rc = ima_restore_measurement_list(kexec_buffer_size, |
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kexec_buffer); |
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if (rc != 0) |
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pr_err("Failed to restore the measurement list: %d\n", |
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rc); |
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ima_free_kexec_buffer(); |
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break; |
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case -ENOTSUPP: |
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pr_debug("Restoring the measurement list not supported\n"); |
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break; |
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case -ENOENT: |
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pr_debug("No measurement list to restore\n"); |
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break; |
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default: |
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pr_debug("Error restoring the measurement list: %d\n", rc); |
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} |
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}
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