12874c5fdSThomas Gleixner // SPDX-License-Identifier: GPL-2.0-or-later 294c3aac5SMimi Zohar /* 394c3aac5SMimi Zohar * Copyright (C) 2016 IBM Corporation 494c3aac5SMimi Zohar * 594c3aac5SMimi Zohar * Authors: 694c3aac5SMimi Zohar * Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com> 794c3aac5SMimi Zohar * Mimi Zohar <zohar@linux.vnet.ibm.com> 894c3aac5SMimi Zohar */ 9de636769SPetr Vorel 107b8589ccSMimi Zohar #include <linux/seq_file.h> 117b8589ccSMimi Zohar #include <linux/vmalloc.h> 127b8589ccSMimi Zohar #include <linux/kexec.h> 1394c3aac5SMimi Zohar #include "ima.h" 1494c3aac5SMimi Zohar 157b8589ccSMimi Zohar #ifdef CONFIG_IMA_KEXEC 167b8589ccSMimi Zohar static int ima_dump_measurement_list(unsigned long *buffer_size, void **buffer, 177b8589ccSMimi Zohar unsigned long segment_size) 187b8589ccSMimi Zohar { 197b8589ccSMimi Zohar struct ima_queue_entry *qe; 207b8589ccSMimi Zohar struct seq_file file; 21d68a6fe9SMimi Zohar struct ima_kexec_hdr khdr; 227b8589ccSMimi Zohar int ret = 0; 237b8589ccSMimi Zohar 247b8589ccSMimi Zohar /* segment size can't change between kexec load and execute */ 257b8589ccSMimi Zohar file.buf = vmalloc(segment_size); 267b8589ccSMimi Zohar if (!file.buf) { 277b8589ccSMimi Zohar ret = -ENOMEM; 287b8589ccSMimi Zohar goto out; 297b8589ccSMimi Zohar } 307b8589ccSMimi Zohar 317b8589ccSMimi Zohar file.size = segment_size; 327b8589ccSMimi Zohar file.read_pos = 0; 337b8589ccSMimi Zohar file.count = sizeof(khdr); /* reserved space */ 347b8589ccSMimi Zohar 35d68a6fe9SMimi Zohar memset(&khdr, 0, sizeof(khdr)); 36d68a6fe9SMimi Zohar khdr.version = 1; 377b8589ccSMimi Zohar list_for_each_entry_rcu(qe, &ima_measurements, later) { 387b8589ccSMimi Zohar if (file.count < file.size) { 397b8589ccSMimi Zohar khdr.count++; 407b8589ccSMimi Zohar ima_measurements_show(&file, qe); 417b8589ccSMimi Zohar } else { 427b8589ccSMimi Zohar ret = -EINVAL; 437b8589ccSMimi Zohar break; 447b8589ccSMimi Zohar } 457b8589ccSMimi Zohar } 467b8589ccSMimi Zohar 477b8589ccSMimi Zohar if (ret < 0) 487b8589ccSMimi Zohar goto out; 497b8589ccSMimi Zohar 507b8589ccSMimi Zohar /* 517b8589ccSMimi Zohar * fill in reserved space with some buffer details 527b8589ccSMimi Zohar * (eg. version, buffer size, number of measurements) 537b8589ccSMimi Zohar */ 547b8589ccSMimi Zohar khdr.buffer_size = file.count; 55d68a6fe9SMimi Zohar if (ima_canonical_fmt) { 56d68a6fe9SMimi Zohar khdr.version = cpu_to_le16(khdr.version); 57d68a6fe9SMimi Zohar khdr.count = cpu_to_le64(khdr.count); 58d68a6fe9SMimi Zohar khdr.buffer_size = cpu_to_le64(khdr.buffer_size); 59d68a6fe9SMimi Zohar } 607b8589ccSMimi Zohar memcpy(file.buf, &khdr, sizeof(khdr)); 61d68a6fe9SMimi Zohar 627b8589ccSMimi Zohar print_hex_dump(KERN_DEBUG, "ima dump: ", DUMP_PREFIX_NONE, 637b8589ccSMimi Zohar 16, 1, file.buf, 647b8589ccSMimi Zohar file.count < 100 ? file.count : 100, true); 657b8589ccSMimi Zohar 667b8589ccSMimi Zohar *buffer_size = file.count; 677b8589ccSMimi Zohar *buffer = file.buf; 687b8589ccSMimi Zohar out: 697b8589ccSMimi Zohar if (ret == -EINVAL) 707b8589ccSMimi Zohar vfree(file.buf); 717b8589ccSMimi Zohar return ret; 727b8589ccSMimi Zohar } 737b8589ccSMimi Zohar 747b8589ccSMimi Zohar /* 757b8589ccSMimi Zohar * Called during kexec_file_load so that IMA can add a segment to the kexec 767b8589ccSMimi Zohar * image for the measurement list for the next kernel. 777b8589ccSMimi Zohar * 787b8589ccSMimi Zohar * This function assumes that kexec_mutex is held. 797b8589ccSMimi Zohar */ 807b8589ccSMimi Zohar void ima_add_kexec_buffer(struct kimage *image) 817b8589ccSMimi Zohar { 827b8589ccSMimi Zohar struct kexec_buf kbuf = { .image = image, .buf_align = PAGE_SIZE, 837b8589ccSMimi Zohar .buf_min = 0, .buf_max = ULONG_MAX, 847b8589ccSMimi Zohar .top_down = true }; 857b8589ccSMimi Zohar unsigned long binary_runtime_size; 867b8589ccSMimi Zohar 877b8589ccSMimi Zohar /* use more understandable variable names than defined in kbuf */ 887b8589ccSMimi Zohar void *kexec_buffer = NULL; 897b8589ccSMimi Zohar size_t kexec_buffer_size; 907b8589ccSMimi Zohar size_t kexec_segment_size; 917b8589ccSMimi Zohar int ret; 927b8589ccSMimi Zohar 937b8589ccSMimi Zohar /* 947b8589ccSMimi Zohar * Reserve an extra half page of memory for additional measurements 957b8589ccSMimi Zohar * added during the kexec load. 967b8589ccSMimi Zohar */ 977b8589ccSMimi Zohar binary_runtime_size = ima_get_binary_runtime_size(); 987b8589ccSMimi Zohar if (binary_runtime_size >= ULONG_MAX - PAGE_SIZE) 997b8589ccSMimi Zohar kexec_segment_size = ULONG_MAX; 1007b8589ccSMimi Zohar else 1017b8589ccSMimi Zohar kexec_segment_size = ALIGN(ima_get_binary_runtime_size() + 1027b8589ccSMimi Zohar PAGE_SIZE / 2, PAGE_SIZE); 1037b8589ccSMimi Zohar if ((kexec_segment_size == ULONG_MAX) || 104ca79b0c2SArun KS ((kexec_segment_size >> PAGE_SHIFT) > totalram_pages() / 2)) { 1057b8589ccSMimi Zohar pr_err("Binary measurement list too large.\n"); 1067b8589ccSMimi Zohar return; 1077b8589ccSMimi Zohar } 1087b8589ccSMimi Zohar 1097b8589ccSMimi Zohar ima_dump_measurement_list(&kexec_buffer_size, &kexec_buffer, 1107b8589ccSMimi Zohar kexec_segment_size); 1117b8589ccSMimi Zohar if (!kexec_buffer) { 1127b8589ccSMimi Zohar pr_err("Not enough memory for the kexec measurement buffer.\n"); 1137b8589ccSMimi Zohar return; 1147b8589ccSMimi Zohar } 1157b8589ccSMimi Zohar 1167b8589ccSMimi Zohar kbuf.buffer = kexec_buffer; 1177b8589ccSMimi Zohar kbuf.bufsz = kexec_buffer_size; 1187b8589ccSMimi Zohar kbuf.memsz = kexec_segment_size; 1197b8589ccSMimi Zohar ret = kexec_add_buffer(&kbuf); 1207b8589ccSMimi Zohar if (ret) { 1217b8589ccSMimi Zohar pr_err("Error passing over kexec measurement buffer.\n"); 1226d14c651SLakshmi Ramasubramanian vfree(kexec_buffer); 1237b8589ccSMimi Zohar return; 1247b8589ccSMimi Zohar } 1257b8589ccSMimi Zohar 1267b8589ccSMimi Zohar ret = arch_ima_add_kexec_buffer(image, kbuf.mem, kexec_segment_size); 1277b8589ccSMimi Zohar if (ret) { 1287b8589ccSMimi Zohar pr_err("Error passing over kexec measurement buffer.\n"); 1297b8589ccSMimi Zohar return; 1307b8589ccSMimi Zohar } 1317b8589ccSMimi Zohar 132*f31e3386SLakshmi Ramasubramanian image->ima_buffer = kexec_buffer; 133*f31e3386SLakshmi Ramasubramanian 1347b8589ccSMimi Zohar pr_debug("kexec measurement buffer for the loaded kernel at 0x%lx.\n", 1357b8589ccSMimi Zohar kbuf.mem); 1367b8589ccSMimi Zohar } 1377b8589ccSMimi Zohar #endif /* IMA_KEXEC */ 1387b8589ccSMimi Zohar 13994c3aac5SMimi Zohar /* 14094c3aac5SMimi Zohar * Restore the measurement list from the previous kernel. 14194c3aac5SMimi Zohar */ 14294c3aac5SMimi Zohar void ima_load_kexec_buffer(void) 14394c3aac5SMimi Zohar { 14494c3aac5SMimi Zohar void *kexec_buffer = NULL; 14594c3aac5SMimi Zohar size_t kexec_buffer_size = 0; 14694c3aac5SMimi Zohar int rc; 14794c3aac5SMimi Zohar 14894c3aac5SMimi Zohar rc = ima_get_kexec_buffer(&kexec_buffer, &kexec_buffer_size); 14994c3aac5SMimi Zohar switch (rc) { 15094c3aac5SMimi Zohar case 0: 15194c3aac5SMimi Zohar rc = ima_restore_measurement_list(kexec_buffer_size, 15294c3aac5SMimi Zohar kexec_buffer); 15394c3aac5SMimi Zohar if (rc != 0) 15494c3aac5SMimi Zohar pr_err("Failed to restore the measurement list: %d\n", 15594c3aac5SMimi Zohar rc); 15694c3aac5SMimi Zohar 15794c3aac5SMimi Zohar ima_free_kexec_buffer(); 15894c3aac5SMimi Zohar break; 15994c3aac5SMimi Zohar case -ENOTSUPP: 16094c3aac5SMimi Zohar pr_debug("Restoring the measurement list not supported\n"); 16194c3aac5SMimi Zohar break; 16294c3aac5SMimi Zohar case -ENOENT: 16394c3aac5SMimi Zohar pr_debug("No measurement list to restore\n"); 16494c3aac5SMimi Zohar break; 16594c3aac5SMimi Zohar default: 16694c3aac5SMimi Zohar pr_debug("Error restoring the measurement list: %d\n", rc); 16794c3aac5SMimi Zohar } 16894c3aac5SMimi Zohar } 169