| /* |
| * EIF (Enclave Image Format) related helpers |
| * |
| * Copyright (c) 2024 Dorjoy Chowdhury <dorjoychy111@gmail.com> |
| * |
| * This work is licensed under the terms of the GNU GPL, version 2 or |
| * (at your option) any later version. See the COPYING file in the |
| * top-level directory. |
| */ |
| |
| #include "qemu/osdep.h" |
| #include "qemu/bswap.h" |
| #include "qapi/error.h" |
| #include "crypto/hash.h" |
| #include "crypto/x509-utils.h" |
| #include <zlib.h> /* for crc32 */ |
| #include <cbor.h> |
| |
| #include "hw/core/eif.h" |
| |
| #define MAX_SECTIONS 32 |
| |
| /* members are ordered according to field order in .eif file */ |
| typedef struct EifHeader { |
| uint8_t magic[4]; /* must be .eif in ascii i.e., [46, 101, 105, 102] */ |
| uint16_t version; |
| uint16_t flags; |
| uint64_t default_memory; |
| uint64_t default_cpus; |
| uint16_t reserved; |
| uint16_t section_cnt; |
| uint64_t section_offsets[MAX_SECTIONS]; |
| uint64_t section_sizes[MAX_SECTIONS]; |
| uint32_t unused; |
| uint32_t eif_crc32; |
| } QEMU_PACKED EifHeader; |
| |
| /* members are ordered according to field order in .eif file */ |
| typedef struct EifSectionHeader { |
| /* |
| * 0 = invalid, 1 = kernel, 2 = cmdline, 3 = ramdisk, 4 = signature, |
| * 5 = metadata |
| */ |
| uint16_t section_type; |
| uint16_t flags; |
| uint64_t section_size; |
| } QEMU_PACKED EifSectionHeader; |
| |
| enum EifSectionTypes { |
| EIF_SECTION_INVALID = 0, |
| EIF_SECTION_KERNEL = 1, |
| EIF_SECTION_CMDLINE = 2, |
| EIF_SECTION_RAMDISK = 3, |
| EIF_SECTION_SIGNATURE = 4, |
| EIF_SECTION_METADATA = 5, |
| EIF_SECTION_MAX = 6, |
| }; |
| |
| static const char *section_type_to_string(uint16_t type) |
| { |
| const char *str; |
| switch (type) { |
| case EIF_SECTION_INVALID: |
| str = "invalid"; |
| break; |
| case EIF_SECTION_KERNEL: |
| str = "kernel"; |
| break; |
| case EIF_SECTION_CMDLINE: |
| str = "cmdline"; |
| break; |
| case EIF_SECTION_RAMDISK: |
| str = "ramdisk"; |
| break; |
| case EIF_SECTION_SIGNATURE: |
| str = "signature"; |
| break; |
| case EIF_SECTION_METADATA: |
| str = "metadata"; |
| break; |
| default: |
| str = "unknown"; |
| break; |
| } |
| |
| return str; |
| } |
| |
| static bool read_eif_header(FILE *f, EifHeader *header, uint32_t *crc, |
| Error **errp) |
| { |
| size_t got; |
| size_t header_size = sizeof(*header); |
| |
| got = fread(header, 1, header_size, f); |
| if (got != header_size) { |
| error_setg(errp, "Failed to read EIF header"); |
| return false; |
| } |
| |
| if (memcmp(header->magic, ".eif", 4) != 0) { |
| error_setg(errp, "Invalid EIF image. Magic mismatch."); |
| return false; |
| } |
| |
| /* Exclude header->eif_crc32 field from CRC calculation */ |
| *crc = crc32(*crc, (uint8_t *)header, header_size - 4); |
| |
| header->version = be16_to_cpu(header->version); |
| header->flags = be16_to_cpu(header->flags); |
| header->default_memory = be64_to_cpu(header->default_memory); |
| header->default_cpus = be64_to_cpu(header->default_cpus); |
| header->reserved = be16_to_cpu(header->reserved); |
| header->section_cnt = be16_to_cpu(header->section_cnt); |
| |
| for (int i = 0; i < MAX_SECTIONS; ++i) { |
| header->section_offsets[i] = be64_to_cpu(header->section_offsets[i]); |
| } |
| |
| for (int i = 0; i < MAX_SECTIONS; ++i) { |
| header->section_sizes[i] = be64_to_cpu(header->section_sizes[i]); |
| if (header->section_sizes[i] > SSIZE_MAX) { |
| error_setg(errp, "Invalid EIF image. Section size out of bounds"); |
| return false; |
| } |
| } |
| |
| header->unused = be32_to_cpu(header->unused); |
| header->eif_crc32 = be32_to_cpu(header->eif_crc32); |
| return true; |
| } |
| |
| static bool read_eif_section_header(FILE *f, EifSectionHeader *section_header, |
| uint32_t *crc, Error **errp) |
| { |
| size_t got; |
| size_t section_header_size = sizeof(*section_header); |
| |
| got = fread(section_header, 1, section_header_size, f); |
| if (got != section_header_size) { |
| error_setg(errp, "Failed to read EIF section header"); |
| return false; |
| } |
| |
| *crc = crc32(*crc, (uint8_t *)section_header, section_header_size); |
| |
| section_header->section_type = be16_to_cpu(section_header->section_type); |
| section_header->flags = be16_to_cpu(section_header->flags); |
| section_header->section_size = be64_to_cpu(section_header->section_size); |
| return true; |
| } |
| |
| /* |
| * Upon success, the caller is responsible for unlinking and freeing *tmp_path. |
| */ |
| static bool get_tmp_file(const char *template, char **tmp_path, Error **errp) |
| { |
| int tmp_fd; |
| |
| *tmp_path = NULL; |
| tmp_fd = g_file_open_tmp(template, tmp_path, NULL); |
| if (tmp_fd < 0 || *tmp_path == NULL) { |
| error_setg(errp, "Failed to create temporary file for template %s", |
| template); |
| return false; |
| } |
| |
| close(tmp_fd); |
| return true; |
| } |
| |
| static void safe_fclose(FILE *f) |
| { |
| if (f) { |
| fclose(f); |
| } |
| } |
| |
| static void safe_unlink(char *f) |
| { |
| if (f) { |
| unlink(f); |
| } |
| } |
| |
| /* |
| * Upon success, the caller is reponsible for unlinking and freeing *kernel_path |
| */ |
| static bool read_eif_kernel(FILE *f, uint64_t size, char **kernel_path, |
| QCryptoHash *hash0, QCryptoHash *hash1, |
| uint32_t *crc, Error **errp) |
| { |
| size_t got; |
| FILE *tmp_file = NULL; |
| uint8_t *kernel = g_try_malloc(size); |
| if (!kernel) { |
| error_setg(errp, "Out of memory reading kernel section"); |
| goto cleanup; |
| } |
| |
| *kernel_path = NULL; |
| if (!get_tmp_file("eif-kernel-XXXXXX", kernel_path, errp)) { |
| goto cleanup; |
| } |
| |
| tmp_file = fopen(*kernel_path, "wb"); |
| if (tmp_file == NULL) { |
| error_setg_errno(errp, errno, "Failed to open temporary file %s", |
| *kernel_path); |
| goto cleanup; |
| } |
| |
| got = fread(kernel, 1, size, f); |
| if ((uint64_t) got != size) { |
| error_setg(errp, "Failed to read EIF kernel section data"); |
| goto cleanup; |
| } |
| |
| got = fwrite(kernel, 1, size, tmp_file); |
| if ((uint64_t) got != size) { |
| error_setg(errp, "Failed to write EIF kernel section data to temporary" |
| " file"); |
| goto cleanup; |
| } |
| |
| *crc = crc32(*crc, kernel, size); |
| if (qcrypto_hash_update(hash0, (char *)kernel, size, errp) != 0 || |
| qcrypto_hash_update(hash1, (char *)kernel, size, errp) != 0) { |
| goto cleanup; |
| } |
| g_free(kernel); |
| fclose(tmp_file); |
| |
| return true; |
| |
| cleanup: |
| safe_fclose(tmp_file); |
| |
| safe_unlink(*kernel_path); |
| g_free(*kernel_path); |
| *kernel_path = NULL; |
| |
| g_free(kernel); |
| return false; |
| } |
| |
| static bool read_eif_cmdline(FILE *f, uint64_t size, char *cmdline, |
| QCryptoHash *hash0, QCryptoHash *hash1, |
| uint32_t *crc, Error **errp) |
| { |
| size_t got = fread(cmdline, 1, size, f); |
| if ((uint64_t) got != size) { |
| error_setg(errp, "Failed to read EIF cmdline section data"); |
| return false; |
| } |
| |
| *crc = crc32(*crc, (uint8_t *)cmdline, size); |
| if (qcrypto_hash_update(hash0, cmdline, size, errp) != 0 || |
| qcrypto_hash_update(hash1, cmdline, size, errp) != 0) { |
| return false; |
| } |
| return true; |
| } |
| |
| static bool read_eif_ramdisk(FILE *eif, FILE *initrd, uint64_t size, |
| QCryptoHash *hash0, QCryptoHash *h, uint32_t *crc, |
| Error **errp) |
| { |
| size_t got; |
| bool ret = false; |
| uint8_t *ramdisk = g_try_malloc(size); |
| if (!ramdisk) { |
| error_setg(errp, "Out of memory reading initrd section"); |
| goto cleanup; |
| } |
| |
| got = fread(ramdisk, 1, size, eif); |
| if ((uint64_t) got != size) { |
| error_setg(errp, "Failed to read EIF ramdisk section data"); |
| goto cleanup; |
| } |
| |
| got = fwrite(ramdisk, 1, size, initrd); |
| if ((uint64_t) got != size) { |
| error_setg(errp, "Failed to write EIF ramdisk data to temporary file"); |
| goto cleanup; |
| } |
| |
| *crc = crc32(*crc, ramdisk, size); |
| if (qcrypto_hash_update(hash0, (char *)ramdisk, size, errp) != 0 || |
| qcrypto_hash_update(h, (char *)ramdisk, size, errp) != 0) { |
| goto cleanup; |
| } |
| ret = true; |
| |
| cleanup: |
| g_free(ramdisk); |
| return ret; |
| } |
| |
| static bool get_signature_fingerprint_sha384(FILE *eif, uint64_t size, |
| uint8_t *sha384, |
| uint32_t *crc, |
| Error **errp) |
| { |
| size_t got; |
| g_autofree uint8_t *sig = NULL; |
| g_autofree uint8_t *cert = NULL; |
| cbor_item_t *item = NULL; |
| cbor_item_t *pcr0 = NULL; |
| size_t len; |
| size_t hash_len = QCRYPTO_HASH_DIGEST_LEN_SHA384; |
| struct cbor_pair *pair; |
| struct cbor_load_result result; |
| bool ret = false; |
| |
| sig = g_try_malloc(size); |
| if (!sig) { |
| error_setg(errp, "Out of memory reading signature section"); |
| goto cleanup; |
| } |
| |
| got = fread(sig, 1, size, eif); |
| if ((uint64_t) got != size) { |
| error_setg(errp, "Failed to read EIF signature section data"); |
| goto cleanup; |
| } |
| |
| *crc = crc32(*crc, sig, size); |
| |
| item = cbor_load(sig, size, &result); |
| if (!item || result.error.code != CBOR_ERR_NONE) { |
| error_setg(errp, "Failed to load signature section data as CBOR"); |
| goto cleanup; |
| } |
| if (!cbor_isa_array(item) || cbor_array_size(item) < 1) { |
| error_setg(errp, "Invalid signature CBOR"); |
| goto cleanup; |
| } |
| pcr0 = cbor_array_get(item, 0); |
| if (!pcr0) { |
| error_setg(errp, "Failed to get PCR0 signature"); |
| goto cleanup; |
| } |
| if (!cbor_isa_map(pcr0) || cbor_map_size(pcr0) != 2) { |
| error_setg(errp, "Invalid signature CBOR"); |
| goto cleanup; |
| } |
| pair = cbor_map_handle(pcr0); |
| if (!cbor_isa_string(pair->key) || cbor_string_length(pair->key) != 19 || |
| memcmp(cbor_string_handle(pair->key), "signing_certificate", 19) != 0) { |
| error_setg(errp, "Invalid signautre CBOR"); |
| goto cleanup; |
| } |
| if (!cbor_isa_array(pair->value)) { |
| error_setg(errp, "Invalid signature CBOR"); |
| goto cleanup; |
| } |
| len = cbor_array_size(pair->value); |
| if (len == 0) { |
| error_setg(errp, "Invalid signature CBOR"); |
| goto cleanup; |
| } |
| cert = g_try_malloc(len); |
| if (!cert) { |
| error_setg(errp, "Out of memory reading signature section"); |
| goto cleanup; |
| } |
| |
| for (int i = 0; i < len; ++i) { |
| cbor_item_t *tmp = cbor_array_get(pair->value, i); |
| if (!tmp) { |
| error_setg(errp, "Invalid signature CBOR"); |
| goto cleanup; |
| } |
| if (!cbor_isa_uint(tmp) || cbor_int_get_width(tmp) != CBOR_INT_8) { |
| cbor_decref(&tmp); |
| error_setg(errp, "Invalid signature CBOR"); |
| goto cleanup; |
| } |
| cert[i] = cbor_get_uint8(tmp); |
| cbor_decref(&tmp); |
| } |
| |
| if (qcrypto_get_x509_cert_fingerprint(cert, len, QCRYPTO_HASH_ALGO_SHA384, |
| sha384, &hash_len, errp)) { |
| goto cleanup; |
| } |
| |
| ret = true; |
| |
| cleanup: |
| if (pcr0) { |
| cbor_decref(&pcr0); |
| } |
| if (item) { |
| cbor_decref(&item); |
| } |
| return ret; |
| } |
| |
| /* Expects file to have offset 0 before this function is called */ |
| static long get_file_size(FILE *f, Error **errp) |
| { |
| long size; |
| |
| if (fseek(f, 0, SEEK_END) != 0) { |
| error_setg_errno(errp, errno, "Failed to seek to the end of file"); |
| return -1; |
| } |
| |
| size = ftell(f); |
| if (size == -1) { |
| error_setg_errno(errp, errno, "Failed to get offset"); |
| return -1; |
| } |
| |
| if (fseek(f, 0, SEEK_SET) != 0) { |
| error_setg_errno(errp, errno, "Failed to seek back to the start"); |
| return -1; |
| } |
| |
| return size; |
| } |
| |
| static bool get_SHA384_hash(QCryptoHash *h, uint8_t *hash, Error **errp) |
| { |
| size_t hash_len = QCRYPTO_HASH_DIGEST_LEN_SHA384; |
| return qcrypto_hash_finalize_bytes(h, &hash, &hash_len, errp) == 0; |
| } |
| |
| /* |
| * Upon success, the caller is reponsible for unlinking and freeing |
| * *kernel_path, *initrd_path and freeing *cmdline. |
| */ |
| bool read_eif_file(const char *eif_path, const char *machine_initrd, |
| char **kernel_path, char **initrd_path, char **cmdline, |
| uint8_t *image_hash, uint8_t *bootstrap_hash, |
| uint8_t *app_hash, uint8_t *fingerprint_hash, |
| bool *signature_found, Error **errp) |
| { |
| FILE *f = NULL; |
| FILE *machine_initrd_f = NULL; |
| FILE *initrd_path_f = NULL; |
| long machine_initrd_size; |
| uint32_t crc = 0; |
| EifHeader eif_header; |
| bool seen_sections[EIF_SECTION_MAX] = {false}; |
| /* kernel + ramdisks + cmdline SHA384 hash */ |
| g_autoptr(QCryptoHash) hash0 = NULL; |
| /* kernel + boot ramdisk + cmdline SHA384 hash */ |
| g_autoptr(QCryptoHash) hash1 = NULL; |
| /* application ramdisk(s) SHA384 hash */ |
| g_autoptr(QCryptoHash) hash2 = NULL; |
| |
| *signature_found = false; |
| *kernel_path = *initrd_path = *cmdline = NULL; |
| |
| hash0 = qcrypto_hash_new(QCRYPTO_HASH_ALGO_SHA384, errp); |
| if (!hash0) { |
| goto cleanup; |
| } |
| hash1 = qcrypto_hash_new(QCRYPTO_HASH_ALGO_SHA384, errp); |
| if (!hash1) { |
| goto cleanup; |
| } |
| hash2 = qcrypto_hash_new(QCRYPTO_HASH_ALGO_SHA384, errp); |
| if (!hash2) { |
| goto cleanup; |
| } |
| |
| f = fopen(eif_path, "rb"); |
| if (f == NULL) { |
| error_setg_errno(errp, errno, "Failed to open %s", eif_path); |
| goto cleanup; |
| } |
| |
| if (!read_eif_header(f, &eif_header, &crc, errp)) { |
| goto cleanup; |
| } |
| |
| if (eif_header.version < 4) { |
| error_setg(errp, "Expected EIF version 4 or greater"); |
| goto cleanup; |
| } |
| |
| if (eif_header.flags != 0) { |
| error_setg(errp, "Expected EIF flags to be 0"); |
| goto cleanup; |
| } |
| |
| if (eif_header.section_cnt > MAX_SECTIONS) { |
| error_setg(errp, "EIF header section count must not be greater than " |
| "%d but found %d", MAX_SECTIONS, eif_header.section_cnt); |
| goto cleanup; |
| } |
| |
| for (int i = 0; i < eif_header.section_cnt; ++i) { |
| EifSectionHeader hdr; |
| uint16_t section_type; |
| |
| if (eif_header.section_offsets[i] > OFF_MAX) { |
| error_setg(errp, "Invalid EIF image. Section offset out of bounds"); |
| goto cleanup; |
| } |
| if (fseek(f, eif_header.section_offsets[i], SEEK_SET) != 0) { |
| error_setg_errno(errp, errno, "Failed to offset to %" PRIu64 " in EIF file", |
| eif_header.section_offsets[i]); |
| goto cleanup; |
| } |
| |
| if (!read_eif_section_header(f, &hdr, &crc, errp)) { |
| goto cleanup; |
| } |
| |
| if (hdr.flags != 0) { |
| error_setg(errp, "Expected EIF section header flags to be 0"); |
| goto cleanup; |
| } |
| |
| if (eif_header.section_sizes[i] != hdr.section_size) { |
| error_setg(errp, "EIF section size mismatch between header and " |
| "section header: header %" PRIu64 ", section header %" PRIu64, |
| eif_header.section_sizes[i], |
| hdr.section_size); |
| goto cleanup; |
| } |
| |
| section_type = hdr.section_type; |
| |
| switch (section_type) { |
| case EIF_SECTION_KERNEL: |
| if (seen_sections[EIF_SECTION_KERNEL]) { |
| error_setg(errp, "Invalid EIF image. More than 1 kernel " |
| "section"); |
| goto cleanup; |
| } |
| |
| if (!read_eif_kernel(f, hdr.section_size, kernel_path, hash0, |
| hash1, &crc, errp)) { |
| goto cleanup; |
| } |
| |
| break; |
| case EIF_SECTION_CMDLINE: |
| { |
| uint64_t size; |
| if (seen_sections[EIF_SECTION_CMDLINE]) { |
| error_setg(errp, "Invalid EIF image. More than 1 cmdline " |
| "section"); |
| goto cleanup; |
| } |
| size = hdr.section_size; |
| *cmdline = g_try_malloc(size + 1); |
| if (!*cmdline) { |
| error_setg(errp, "Out of memory reading command line section"); |
| goto cleanup; |
| } |
| if (!read_eif_cmdline(f, size, *cmdline, hash0, hash1, &crc, |
| errp)) { |
| goto cleanup; |
| } |
| (*cmdline)[size] = '\0'; |
| |
| break; |
| } |
| case EIF_SECTION_RAMDISK: |
| { |
| QCryptoHash *h = hash2; |
| if (!seen_sections[EIF_SECTION_RAMDISK]) { |
| /* |
| * If this is the first time we are seeing a ramdisk section, |
| * we need to: |
| * 1) hash it into bootstrap (hash1) instead of app (hash2) |
| * along with image (hash0) |
| * 2) create the initrd temporary file. |
| */ |
| h = hash1; |
| if (!get_tmp_file("eif-initrd-XXXXXX", initrd_path, errp)) { |
| goto cleanup; |
| } |
| initrd_path_f = fopen(*initrd_path, "wb"); |
| if (initrd_path_f == NULL) { |
| error_setg_errno(errp, errno, "Failed to open file %s", |
| *initrd_path); |
| goto cleanup; |
| } |
| } |
| |
| if (!read_eif_ramdisk(f, initrd_path_f, hdr.section_size, hash0, h, |
| &crc, errp)) { |
| goto cleanup; |
| } |
| |
| break; |
| } |
| case EIF_SECTION_SIGNATURE: |
| *signature_found = true; |
| if (!get_signature_fingerprint_sha384(f, hdr.section_size, |
| fingerprint_hash, &crc, |
| errp)) { |
| goto cleanup; |
| } |
| break; |
| default: |
| /* other sections including invalid or unknown sections */ |
| { |
| uint8_t *buf; |
| size_t got; |
| uint64_t size = hdr.section_size; |
| buf = g_try_malloc(size); |
| if (!buf) { |
| error_setg(errp, "Out of memory reading unknown section"); |
| goto cleanup; |
| } |
| got = fread(buf, 1, size, f); |
| if ((uint64_t) got != size) { |
| g_free(buf); |
| error_setg(errp, "Failed to read EIF %s section data", |
| section_type_to_string(section_type)); |
| goto cleanup; |
| } |
| crc = crc32(crc, buf, size); |
| g_free(buf); |
| break; |
| } |
| } |
| |
| if (section_type < EIF_SECTION_MAX) { |
| seen_sections[section_type] = true; |
| } |
| } |
| |
| if (!seen_sections[EIF_SECTION_KERNEL]) { |
| error_setg(errp, "Invalid EIF image. No kernel section."); |
| goto cleanup; |
| } |
| if (!seen_sections[EIF_SECTION_CMDLINE]) { |
| error_setg(errp, "Invalid EIF image. No cmdline section."); |
| goto cleanup; |
| } |
| if (!seen_sections[EIF_SECTION_RAMDISK]) { |
| error_setg(errp, "Invalid EIF image. No ramdisk section."); |
| goto cleanup; |
| } |
| |
| if (eif_header.eif_crc32 != crc) { |
| error_setg(errp, "CRC mismatch. Expected %u but header has %u.", |
| crc, eif_header.eif_crc32); |
| goto cleanup; |
| } |
| |
| /* |
| * Let's append the initrd file from "-initrd" option if any. Although |
| * we pass the crc pointer to read_eif_ramdisk, it is not useful anymore. |
| * We have already done the crc mismatch check above this code. |
| */ |
| if (machine_initrd) { |
| machine_initrd_f = fopen(machine_initrd, "rb"); |
| if (machine_initrd_f == NULL) { |
| error_setg_errno(errp, errno, "Failed to open initrd file %s", |
| machine_initrd); |
| goto cleanup; |
| } |
| |
| machine_initrd_size = get_file_size(machine_initrd_f, errp); |
| if (machine_initrd_size == -1) { |
| goto cleanup; |
| } |
| |
| if (!read_eif_ramdisk(machine_initrd_f, initrd_path_f, |
| machine_initrd_size, hash0, hash2, &crc, errp)) { |
| goto cleanup; |
| } |
| } |
| |
| if (!get_SHA384_hash(hash0, image_hash, errp)) { |
| goto cleanup; |
| } |
| if (!get_SHA384_hash(hash1, bootstrap_hash, errp)) { |
| goto cleanup; |
| } |
| if (!get_SHA384_hash(hash2, app_hash, errp)) { |
| goto cleanup; |
| } |
| |
| fclose(f); |
| fclose(initrd_path_f); |
| safe_fclose(machine_initrd_f); |
| return true; |
| |
| cleanup: |
| safe_fclose(f); |
| safe_fclose(initrd_path_f); |
| safe_fclose(machine_initrd_f); |
| |
| safe_unlink(*kernel_path); |
| g_free(*kernel_path); |
| *kernel_path = NULL; |
| |
| safe_unlink(*initrd_path); |
| g_free(*initrd_path); |
| *initrd_path = NULL; |
| |
| g_free(*cmdline); |
| *cmdline = NULL; |
| |
| return false; |
| } |
