diff options
Diffstat (limited to 'hw/core/eif.c')
| -rw-r--r-- | hw/core/eif.c | 719 |
1 files changed, 719 insertions, 0 deletions
diff --git a/hw/core/eif.c b/hw/core/eif.c new file mode 100644 index 0000000000..7f3b2edc9a --- /dev/null +++ b/hw/core/eif.c @@ -0,0 +1,719 @@ +/* + * 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]); + } + + 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, + uint8_t *kernel, uint32_t *crc, Error **errp) +{ + size_t got; + FILE *tmp_file = NULL; + + *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); + fclose(tmp_file); + + return true; + + cleanup: + safe_fclose(tmp_file); + + safe_unlink(*kernel_path); + g_free(*kernel_path); + *kernel_path = NULL; + + return false; +} + +static bool read_eif_cmdline(FILE *f, uint64_t size, char *cmdline, + 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); + return true; +} + +static bool read_eif_ramdisk(FILE *eif, FILE *initrd, uint64_t size, + uint8_t *ramdisk, uint32_t *crc, Error **errp) +{ + size_t got; + + got = fread(ramdisk, 1, size, eif); + if ((uint64_t) got != size) { + error_setg(errp, "Failed to read EIF ramdisk section data"); + return false; + } + + got = fwrite(ramdisk, 1, size, initrd); + if ((uint64_t) got != size) { + error_setg(errp, "Failed to write EIF ramdisk data to temporary file"); + return false; + } + + *crc = crc32(*crc, ramdisk, size); + return true; +} + +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_malloc(size); + 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_malloc(len); + 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_digest(GList *list, uint8_t *digest, Error **errp) +{ + size_t digest_len = QCRYPTO_HASH_DIGEST_LEN_SHA384; + size_t list_len = g_list_length(list); + struct iovec *iovec_list = g_new0(struct iovec, list_len); + bool ret = true; + GList *l; + int i; + + for (i = 0, l = list; l != NULL; l = l->next, i++) { + iovec_list[i] = *(struct iovec *) l->data; + } + + if (qcrypto_hash_bytesv(QCRYPTO_HASH_ALGO_SHA384, iovec_list, list_len, + &digest, &digest_len, errp) < 0) { + ret = false; + } + + g_free(iovec_list); + return ret; +} + +static void free_iovec(struct iovec *iov) +{ + if (iov) { + g_free(iov->iov_base); + g_free(iov); + } +} + +/* + * 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_sha384, uint8_t *bootstrap_sha384, + uint8_t *app_sha384, uint8_t *fingerprint_sha384, + 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 */ + GList *iov_PCR0 = NULL; + /* kernel + boot ramdisk + cmdline sha384 hash */ + GList *iov_PCR1 = NULL; + /* application ramdisk(s) hash */ + GList *iov_PCR2 = NULL; + uint8_t *ptr = NULL; + struct iovec *iov_ptr = NULL; + + *signature_found = false; + *kernel_path = *initrd_path = *cmdline = NULL; + + 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 (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; + } + + ptr = g_malloc(hdr.section_size); + + iov_ptr = g_malloc(sizeof(struct iovec)); + iov_ptr->iov_base = ptr; + iov_ptr->iov_len = hdr.section_size; + + iov_PCR0 = g_list_append(iov_PCR0, iov_ptr); + iov_PCR1 = g_list_append(iov_PCR1, iov_ptr); + + if (!read_eif_kernel(f, hdr.section_size, kernel_path, ptr, &crc, + errp)) { + goto cleanup; + } + + break; + case EIF_SECTION_CMDLINE: + { + uint64_t size; + uint8_t *cmdline_copy; + 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_malloc(size + 1); + if (!read_eif_cmdline(f, size, *cmdline, &crc, errp)) { + goto cleanup; + } + (*cmdline)[size] = '\0'; + + /* + * We make a copy of '*cmdline' for putting it in iovecs so that + * we can easily free all the iovec entries later as we cannot + * free '*cmdline' which is used by the caller. + */ + cmdline_copy = g_memdup2(*cmdline, size); + + iov_ptr = g_malloc(sizeof(struct iovec)); + iov_ptr->iov_base = cmdline_copy; + iov_ptr->iov_len = size; + + iov_PCR0 = g_list_append(iov_PCR0, iov_ptr); + iov_PCR1 = g_list_append(iov_PCR1, iov_ptr); + break; + } + case EIF_SECTION_RAMDISK: + { + if (!seen_sections[EIF_SECTION_RAMDISK]) { + /* + * If this is the first time we are seeing a ramdisk section, + * we need to create the initrd temporary file. + */ + 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; + } + } + + ptr = g_malloc(hdr.section_size); + + iov_ptr = g_malloc(sizeof(struct iovec)); + iov_ptr->iov_base = ptr; + iov_ptr->iov_len = hdr.section_size; + + iov_PCR0 = g_list_append(iov_PCR0, iov_ptr); + /* + * If it's the first ramdisk, we need to hash it into bootstrap + * i.e., iov_PCR1, otherwise we need to hash it into app i.e., + * iov_PCR2. + */ + if (!seen_sections[EIF_SECTION_RAMDISK]) { + iov_PCR1 = g_list_append(iov_PCR1, iov_ptr); + } else { + iov_PCR2 = g_list_append(iov_PCR2, iov_ptr); + } + + if (!read_eif_ramdisk(f, initrd_path_f, hdr.section_size, ptr, + &crc, errp)) { + goto cleanup; + } + + break; + } + case EIF_SECTION_SIGNATURE: + *signature_found = true; + if (!get_signature_fingerprint_sha384(f, hdr.section_size, + fingerprint_sha384, &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_malloc(size); + 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; + } + + ptr = g_malloc(machine_initrd_size); + + iov_ptr = g_malloc(sizeof(struct iovec)); + iov_ptr->iov_base = ptr; + iov_ptr->iov_len = machine_initrd_size; + + iov_PCR0 = g_list_append(iov_PCR0, iov_ptr); + iov_PCR2 = g_list_append(iov_PCR2, iov_ptr); + + if (!read_eif_ramdisk(machine_initrd_f, initrd_path_f, + machine_initrd_size, ptr, &crc, errp)) { + goto cleanup; + } + } + + if (!get_SHA384_digest(iov_PCR0, image_sha384, errp)) { + goto cleanup; + } + if (!get_SHA384_digest(iov_PCR1, bootstrap_sha384, errp)) { + goto cleanup; + } + if (!get_SHA384_digest(iov_PCR2, app_sha384, errp)) { + goto cleanup; + } + + /* + * We only need to free iov_PCR0 entries because iov_PCR1 and + * iov_PCR2 iovec entries are subsets of iov_PCR0 iovec entries. + */ + g_list_free_full(iov_PCR0, (GDestroyNotify) free_iovec); + g_list_free(iov_PCR1); + g_list_free(iov_PCR2); + fclose(f); + fclose(initrd_path_f); + safe_fclose(machine_initrd_f); + return true; + + cleanup: + g_list_free_full(iov_PCR0, (GDestroyNotify) free_iovec); + g_list_free(iov_PCR1); + g_list_free(iov_PCR2); + + 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; +} |