From b0c4c5fbdcc89b44cee2300c5a12cb5e8de0e446 Mon Sep 17 00:00:00 2001 From: Alberto Planas Date: Wed, 13 Mar 2024 22:57:17 +0100 Subject: [PATCH] GRUB with BLS measure boot entries This includes the boot entry file, the kernel and the initrd specified in the entry file. Signed-off-by: Alberto Planas --- src/eventlog.c | 21 +++++++++++++++++++-- src/eventlog.h | 1 + src/oracle.c | 12 +++++++++--- src/sd-boot.c | 28 ++++++++++++++++++++++++---- src/sd-boot.h | 2 ++ src/uapi.h | 3 ++- 6 files changed, 57 insertions(+), 10 deletions(-) diff --git a/src/eventlog.c b/src/eventlog.c index 3574a4d..db18f41 100644 --- a/src/eventlog.c +++ b/src/eventlog.c @@ -33,6 +33,7 @@ #include "digest.h" #include "util.h" #include "uapi.h" +#include "sd-boot.h" #define TPM_EVENT_LOG_MAX_ALGOS 64 @@ -582,8 +583,24 @@ __tpm_event_grub_file_rehash(const tpm_event_t *ev, const tpm_parsed_event_t *pa debug(" assuming the file resides on system partition\n"); md = runtime_digest_rootfs_file(ctx->algo, evspec->path); } else { - debug(" assuming the file resides on EFI boot partition\n"); - md = runtime_digest_efi_file(ctx->algo, evspec->path); + if (sdb_is_boot_entry(evspec->path) && ctx->boot_entry_path) { + debug(" getting different boot entry file from EFI boot partition: %s\n", + ctx->boot_entry_path); + md = runtime_digest_rootfs_file(ctx->algo, ctx->boot_entry_path); + } else + if (sdb_is_kernel(evspec->path) && ctx->boot_entry) { + debug(" getting different kernel from EFI boot partition: %s\n", + ctx->boot_entry->image_path); + md = runtime_digest_efi_file(ctx->algo, ctx->boot_entry->image_path); + } else + if (sdb_is_initrd(evspec->path) && ctx->boot_entry) { + debug(" getting different initrd from EFI boot partition: %s\n", + ctx->boot_entry->initrd_path); + md = runtime_digest_efi_file(ctx->algo, ctx->boot_entry->initrd_path); + } else { + debug(" assuming the file resides on EFI boot partition\n"); + md = runtime_digest_efi_file(ctx->algo, evspec->path); + } } return md; diff --git a/src/eventlog.h b/src/eventlog.h index 8af5eb0..d142744 100644 --- a/src/eventlog.h +++ b/src/eventlog.h @@ -202,6 +202,7 @@ typedef struct tpm_event_log_rehash_ctx { const pecoff_image_info_t *next_stage_img; /* This get set when the user specifies --next-kernel */ + char * boot_entry_path; uapi_boot_entry_t * boot_entry; } tpm_event_log_rehash_ctx_t; diff --git a/src/oracle.c b/src/oracle.c index 0afd910..ac48823 100644 --- a/src/oracle.c +++ b/src/oracle.c @@ -23,6 +23,7 @@ #include #include #include +#include #include "oracle.h" #include "util.h" @@ -653,6 +654,7 @@ predictor_update_eventlog(struct predictor *pred) tpm_event_log_rehash_ctx_t rehash_ctx; tpm_event_t *ev, *stop_event = NULL; bool okay = true; + char boot_entry_path[PATH_MAX]; predictor_pre_scan_eventlog(pred, &stop_event); @@ -663,9 +665,13 @@ predictor_update_eventlog(struct predictor *pred) * systemd ID of the next kernel entry to be booted. * FIXME: we should probably hide this behind a target_platform function. */ - if (pred->boot_entry_id != NULL - && !(rehash_ctx.boot_entry = sdb_identify_boot_entry(pred->boot_entry_id))) - fatal("unable to identify next kernel \"%s\"\n", pred->boot_entry_id); + if (pred->boot_entry_id != NULL) { + snprintf(boot_entry_path, sizeof(boot_entry_path), + "%s/%s", UAPI_BOOT_DIRECTORY, pred->boot_entry_id); + assign_string(&rehash_ctx.boot_entry_path, boot_entry_path); + if (!(rehash_ctx.boot_entry = sdb_identify_boot_entry(pred->boot_entry_id))) + fatal("unable to identify next kernel \"%s\"\n", pred->boot_entry_id); + } for (ev = pred->event_log; ev; ev = ev->next) { tpm_evdigest_t *pcr; diff --git a/src/sd-boot.c b/src/sd-boot.c index ede2569..a16f814 100644 --- a/src/sd-boot.c +++ b/src/sd-boot.c @@ -130,10 +130,9 @@ get_valid_kernel_entry_tokens(void) /* * This should probably use UAPI boot entry logic as well */ -bool -sdb_is_kernel(const char *application) +static bool +is_valid_entry_token(const char *application, const char *prefix) { - static const char prefix[] = "linux-"; const uapi_kernel_entry_tokens_t *match; char *path_copy; int found = 0; @@ -151,7 +150,7 @@ sdb_is_kernel(const char *application) if (!strcmp(ptr, token)) found |= 1; - else if (!strncmp(ptr, prefix, sizeof(prefix) - 1)) + else if (!strncmp(ptr, prefix, strlen(prefix))) found |= 2; } } @@ -160,6 +159,27 @@ sdb_is_kernel(const char *application) return (found == 3); } +bool +sdb_is_kernel(const char *application) +{ + return is_valid_entry_token(application, "linux-"); +} + +bool +sdb_is_initrd(const char *application) +{ + return is_valid_entry_token(application, "initrd-"); +} + +bool +sdb_is_boot_entry(const char *application) +{ + if (!application) + return false; + + return !strncmp(application, UAPI_BOOT_DIRECTORY_EFI, sizeof(UAPI_BOOT_DIRECTORY_EFI) - 1); +} + /* * Identify the next kernel and initrd given an ID */ diff --git a/src/sd-boot.h b/src/sd-boot.h index 0472320..ceab13d 100644 --- a/src/sd-boot.h +++ b/src/sd-boot.h @@ -43,7 +43,9 @@ typedef struct sdb_entry_list { } sdb_entry_list_t; extern uapi_boot_entry_t * sdb_identify_boot_entry(const char *id); +extern bool sdb_is_boot_entry(const char *application); extern bool sdb_is_kernel(const char *application); +extern bool sdb_is_initrd(const char *application); /* This will have to update the systemd json file, and add a new entry. */ extern bool sdb_policy_file_add_entry(const char *filename, diff --git a/src/uapi.h b/src/uapi.h index 96ca7ed..8bcb94f 100644 --- a/src/uapi.h +++ b/src/uapi.h @@ -41,7 +41,8 @@ typedef struct uapi_kernel_entry_tokens { char * entry_token[UAPI_MAX_ENTRY_TOKENS]; } uapi_kernel_entry_tokens_t; -#define UAPI_BOOT_DIRECTORY "/boot/efi/loader/entries" +#define UAPI_BOOT_DIRECTORY_EFI "/loader/entries" +#define UAPI_BOOT_DIRECTORY "/boot/efi" UAPI_BOOT_DIRECTORY_EFI extern uapi_boot_entry_t * uapi_get_boot_entry(const char *id); extern uapi_boot_entry_t * uapi_find_boot_entry(const uapi_kernel_entry_tokens_t *match, const char *machine_id);