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grub2
0014-util-grub-protect-Add-new-tool.patch
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File 0014-util-grub-protect-Add-new-tool.patch of Package grub2
From a913983cb75594e08b425e3c099185b2f4187663 Mon Sep 17 00:00:00 2001 From: Hernan Gatta <hegatta@linux.microsoft.com> Date: Tue, 1 Feb 2022 05:02:57 -0800 Subject: [PATCH 14/14] util/grub-protect: Add new tool To utilize the key protectors framework, there must be a way to protect full-disk encryption keys in the first place. The grub-protect tool includes support for the TPM2 key protector but other protectors that require setup ahead of time can be supported in the future. For the TPM2 key protector, the intended flow is for a user to have a LUKS 1 or LUKS 2-protected fully-encrypted disk. The user then creates a new key file, say by reading /dev/urandom into a file, and creates a new LUKS key slot for this key. Then, the user invokes the grub-protect tool to seal this key file to a set of PCRs using the system's TPM 2.0. The resulting sealed key file is stored in an unencrypted partition such as the EFI System Partition (ESP) so that GRUB may read it. The user also ensures the cryptomount command is included in GRUB's boot script and that it carries the requisite key protector (-k) parameter. Sample usage: $ dd if=/dev/urandom of=key bs=1 count=32 $ sudo cryptsetup luksAddKey /dev/sdb1 key --pbkdf=pbkdf2 --hash=sha512 $ sudo grub-protect --action=add --protector=tpm2 --tpm2-keyfile=key --tpm2-outfile=/boot/efi/boot/grub2/sealed_key Then, in the boot script: tpm2_key_protector_init -k (hd0,gpt1)/boot/grub2/sealed_key cryptomount -u b20f95d0834842bc9197bd78b36732f8 -k tpm2 where the UUID corresponds to /dev/sdb1. Signed-off-by: Hernan Gatta <hegatta@linux.microsoft.com> --- Makefile.util.def | 18 + configure.ac | 1 + util/grub-protect.c | 1314 +++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 1334 insertions(+) create mode 100644 util/grub-protect.c diff --git a/Makefile.util.def b/Makefile.util.def index b3ec2a4bb6..08f681cd8b 100644 --- a/Makefile.util.def +++ b/Makefile.util.def @@ -207,6 +207,24 @@ program = { ldadd = '$(LIBINTL) $(LIBDEVMAPPER) $(LIBZFS) $(LIBNVPAIR) $(LIBGEOM)'; }; +program = { + name = grub-protect; + + common = grub-core/osdep/init.c; + common = grub-core/tpm2/args.c; + common = grub-core/tpm2/buffer.c; + common = grub-core/tpm2/mu.c; + common = grub-core/tpm2/tpm2.c; + common = util/grub-protect.c; + common = util/probe.c; + + ldadd = libgrubmods.a; + ldadd = libgrubgcry.a; + ldadd = libgrubkern.a; + ldadd = grub-core/lib/gnulib/libgnu.a; + ldadd = '$(LIBINTL) $(LIBDEVMAPPER) $(LIBUTIL) $(LIBZFS) $(LIBNVPAIR) $(LIBGEOM)'; +}; + program = { name = grub-mkrelpath; mansection = 1; diff --git a/configure.ac b/configure.ac index 906eb1cedc..ba717a9600 100644 --- a/configure.ac +++ b/configure.ac @@ -71,6 +71,7 @@ grub_TRANSFORM([grub-mkpasswd-pbkdf2]) grub_TRANSFORM([grub-mkrelpath]) grub_TRANSFORM([grub-mkrescue]) grub_TRANSFORM([grub-probe]) +grub_TRANSFORM([grub-protect]) grub_TRANSFORM([grub-reboot]) grub_TRANSFORM([grub-script-check]) grub_TRANSFORM([grub-set-default]) diff --git a/util/grub-protect.c b/util/grub-protect.c new file mode 100644 index 0000000000..23ee78d32a --- /dev/null +++ b/util/grub-protect.c @@ -0,0 +1,1314 @@ +/* + * GRUB -- GRand Unified Bootloader + * Copyright (C) 2022 Microsoft Corporation + * + * GRUB is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * GRUB is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with GRUB. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <config.h> + +#include <errno.h> +#include <fcntl.h> +#include <stdio.h> +#include <string.h> +#include <unistd.h> + +#include <grub/crypto.h> +#include <grub/emu/getroot.h> +#include <grub/emu/hostdisk.h> +#include <grub/emu/misc.h> +#include <grub/tpm2/buffer.h> +#include <grub/tpm2/internal/args.h> +#include <grub/tpm2/mu.h> +#include <grub/tpm2/tcg2.h> +#include <grub/tpm2/tpm2.h> +#include <grub/util/misc.h> + +#pragma GCC diagnostic ignored "-Wmissing-prototypes" +#pragma GCC diagnostic ignored "-Wmissing-declarations" +#include <argp.h> +#pragma GCC diagnostic error "-Wmissing-prototypes" +#pragma GCC diagnostic error "-Wmissing-declarations" + +#include "progname.h" + +/* Unprintable option keys for argp */ +typedef enum grub_protect_opt +{ + /* General */ + GRUB_PROTECT_OPT_ACTION = 'a', + GRUB_PROTECT_OPT_PROTECTOR = 'p', + /* TPM2 */ + GRUB_PROTECT_OPT_TPM2_DEVICE = 0x100, + GRUB_PROTECT_OPT_TPM2_PCRS, + GRUB_PROTECT_OPT_TPM2_ASYMMETRIC, + GRUB_PROTECT_OPT_TPM2_BANK, + GRUB_PROTECT_OPT_TPM2_SRK, + GRUB_PROTECT_OPT_TPM2_KEYFILE, + GRUB_PROTECT_OPT_TPM2_OUTFILE, + GRUB_PROTECT_OPT_TPM2_PERSIST, + GRUB_PROTECT_OPT_TPM2_EVICT +} grub_protect_opt; + +/* Option flags to keep track of specified arguments */ +typedef enum grub_protect_arg +{ + /* General */ + GRUB_PROTECT_ARG_ACTION = 1 << 0, + GRUB_PROTECT_ARG_PROTECTOR = 1 << 1, + /* TPM2 */ + GRUB_PROTECT_ARG_TPM2_DEVICE = 1 << 2, + GRUB_PROTECT_ARG_TPM2_PCRS = 1 << 3, + GRUB_PROTECT_ARG_TPM2_ASYMMETRIC = 1 << 4, + GRUB_PROTECT_ARG_TPM2_BANK = 1 << 5, + GRUB_PROTECT_ARG_TPM2_SRK = 1 << 6, + GRUB_PROTECT_ARG_TPM2_KEYFILE = 1 << 7, + GRUB_PROTECT_ARG_TPM2_OUTFILE = 1 << 8, + GRUB_PROTECT_ARG_TPM2_PERSIST = 1 << 9, + GRUB_PROTECT_ARG_TPM2_EVICT = 1 << 10 +} grub_protect_arg_t; + +typedef enum grub_protect_protector +{ + GRUB_PROTECT_TYPE_ERROR, + GRUB_PROTECT_TYPE_TPM2 +} grub_protect_protector_t; + +typedef enum grub_protect_action +{ + GRUB_PROTECT_ACTION_ERROR, + GRUB_PROTECT_ACTION_ADD, + GRUB_PROTECT_ACTION_REMOVE +} grub_protect_action_t; + +struct grub_protect_args +{ + grub_protect_arg_t args; + grub_protect_action_t action; + grub_protect_protector_t protector; + + const char *tpm2_device; + grub_uint8_t tpm2_pcrs[TPM_MAX_PCRS]; + grub_uint8_t tpm2_pcr_count; + TPM_ALG_ID tpm2_asymmetric; + TPM_ALG_ID tpm2_bank; + TPM_HANDLE tpm2_srk; + const char *tpm2_keyfile; + const char *tpm2_outfile; + int tpm2_persist; + int tpm2_evict; +}; + +static struct argp_option grub_protect_options[] = + { + /* Top-level options */ + { + .name = "action", + .key = 'a', + .arg = "ADD|REMOVE", + .flags = 0, + .doc = + N_("Add or remove a key protector to or from a key."), + .group = 0 + }, + { + .name = "protector", + .key = 'p', + .arg = "TPM2", + .flags = 0, + .doc = + N_("Key protector to use (only TPM2 is currently supported)."), + .group = 0 + }, + /* TPM2 key protector options */ + { + .name = "tpm2-device", + .key = GRUB_PROTECT_OPT_TPM2_DEVICE, + .arg = "FILE", + .flags = 0, + .doc = + N_("Path to the TPM2 device (default is /dev/tpm0)."), + .group = 0 + }, + { + .name = "tpm2-pcrs", + .key = GRUB_PROTECT_OPT_TPM2_PCRS, + .arg = "0[,1]...", + .flags = 0, + .doc = + N_("Comma-separated list of PCRs used to authorize key release " + "(e.g., '7,11', default is 7."), + .group = 0 + }, + { + .name = "tpm2-bank", + .key = GRUB_PROTECT_OPT_TPM2_BANK, + .arg = "SHA1|SHA256|SHA384", + .flags = 0, + .doc = + N_("Bank of PCRs used to authorize key release: " + "SHA1, SHA256 (default), or SHA384."), + .group = 0 + }, + { + .name = "tpm2-keyfile", + .key = GRUB_PROTECT_OPT_TPM2_KEYFILE, + .arg = "FILE", + .flags = 0, + .doc = + N_("Path to a file that contains the cleartext key to protect."), + .group = 0 + }, + { + .name = "tpm2-outfile", + .key = GRUB_PROTECT_OPT_TPM2_OUTFILE, + .arg = "FILE", + .flags = 0, + .doc = + N_("Path to the file that will contain the key after sealing (must be " + "accessible to GRUB during boot)."), + .group = 0 + }, + { + .name = "tpm2-srk", + .key = GRUB_PROTECT_OPT_TPM2_SRK, + .arg = "NUM", + .flags = 0, + .doc = + N_("The SRK handle if the SRK is to be made persistent " + "(default is 0x81000001)."), + .group = 0 + }, + { + .name = "tpm2-asymmetric", + .key = GRUB_PROTECT_OPT_TPM2_ASYMMETRIC, + .arg = "RSA|ECC", + .flags = 0, + .doc = + N_("The type of SRK: RSA (default) or ECC."), + .group = 0 + }, + { + .name = "tpm2-persist", + .key = GRUB_PROTECT_OPT_TPM2_PERSIST, + .arg = NULL, + .flags = 0, + .doc = + N_("Whether to persist the SRK onto the TPM, otherwise it is recreated " + "ephemerally during boot (default is to not persist it)."), + .group = 0 + }, + { + .name = "tpm2-evict", + .key = GRUB_PROTECT_OPT_TPM2_EVICT, + .arg = NULL, + .flags = 0, + .doc = + N_("Evict a previously persisted SRK from the TPM, if any."), + .group = 0 + }, + /* End of list */ + { 0, 0, 0, 0, 0, 0 } + }; + +static int grub_protector_tpm2_fd = -1; + +static grub_err_t +grub_protect_read_file (const char *filepath, void **buffer, + size_t *buffer_size) +{ + grub_err_t err; + FILE *f; + long len; + void *buf; + + f = fopen (filepath, "rb"); + if (!f) + return GRUB_ERR_FILE_NOT_FOUND; + + if (fseek (f, 0, SEEK_END)) + { + err = GRUB_ERR_FILE_READ_ERROR; + goto exit1; + } + + len = ftell (f); + if (!len) + { + err = GRUB_ERR_FILE_READ_ERROR; + goto exit1; + } + + rewind (f); + + buf = grub_malloc (len); + if (!buf) + { + err = GRUB_ERR_OUT_OF_MEMORY; + goto exit1; + } + + if (fread (buf, len, 1, f) != 1) + { + err = GRUB_ERR_FILE_READ_ERROR; + goto exit2; + } + + *buffer = buf; + *buffer_size = len; + + buf = NULL; + err = GRUB_ERR_NONE; + +exit2: + grub_free (buf); + +exit1: + fclose (f); + + return err; +} + +static grub_err_t +grub_protect_write_file (const char *filepath, void *buffer, size_t buffer_size) +{ + grub_err_t err; + FILE *f; + + f = fopen (filepath, "wb"); + if (!f) + return GRUB_ERR_FILE_NOT_FOUND; + + if (fwrite (buffer, buffer_size, 1, f) != 1) + { + err = GRUB_ERR_WRITE_ERROR; + goto exit1; + } + + err = GRUB_ERR_NONE; + +exit1: + fclose (f); + + return err; +} + +static grub_err_t +grub_protect_get_grub_drive_for_file (const char *filepath, char **drive) +{ + grub_err_t err = GRUB_ERR_IO; + char *disk; + char **devices; + char *grub_dev; + char *grub_path; + char *efi_drive; + char *partition; + char *grub_drive; + grub_device_t dev; + grub_size_t grub_drive_len; + int n; + + grub_path = grub_canonicalize_file_name (filepath); + if (!grub_path) + goto exit1; + + devices = grub_guess_root_devices (grub_path); + if (!devices || !devices[0]) + goto exit2; + + disk = devices[0]; + + grub_util_pull_device (disk); + + grub_dev = grub_util_get_grub_dev (disk); + if (!grub_dev) + goto exit3; + + dev = grub_device_open (grub_dev); + if (!dev) + goto exit4; + + efi_drive = grub_util_guess_efi_drive (disk); + if (!efi_drive) + goto exit5; + + partition = grub_partition_get_name (dev->disk->partition); + if (!partition) + goto exit6; + + grub_drive_len = grub_strlen (efi_drive) + grub_strlen (partition) + 3; + grub_drive = grub_malloc (grub_drive_len + 1); + if (!grub_drive) + goto exit7; + + n = grub_snprintf (grub_drive, grub_drive_len + 1, "(%s,%s)", efi_drive, + partition); + if (n != grub_drive_len) + goto exit8; + + *drive = grub_drive; + grub_drive = NULL; + err = GRUB_ERR_NONE; + +exit8: + grub_free (grub_drive); + +exit7: + grub_free (partition); + +exit6: + grub_free (efi_drive); + +exit5: + grub_device_close (dev); + +exit4: + grub_free (grub_dev); + +exit3: + grub_free (devices); + +exit2: + grub_free (grub_path); + +exit1: + return err; +} + +grub_err_t +grub_tcg2_get_max_output_size (grub_size_t *size) +{ + if (!size) + return GRUB_ERR_BAD_ARGUMENT; + + *size = GRUB_TPM2_BUFFER_CAPACITY; + + return GRUB_ERR_NONE; +} + +grub_err_t +grub_tcg2_submit_command (grub_size_t input_size, grub_uint8_t *input, + grub_size_t output_size, grub_uint8_t *output) +{ + static const grub_size_t header_size = sizeof (grub_uint16_t) + + (2 * sizeof(grub_uint32_t)); + + if (write (grub_protector_tpm2_fd, input, input_size) != input_size) + return GRUB_ERR_BAD_DEVICE; + + if (read (grub_protector_tpm2_fd, output, output_size) < header_size) + return GRUB_ERR_BAD_DEVICE; + + return GRUB_ERR_NONE; +} + +static grub_err_t +grub_protect_tpm2_open_device (const char *dev_node) +{ + if (grub_protector_tpm2_fd != -1) + return GRUB_ERR_NONE; + + grub_protector_tpm2_fd = open (dev_node, O_RDWR); + if (grub_protector_tpm2_fd == -1) + { + fprintf (stderr, _("Could not open TPM device (Error: %u).\n"), errno); + return GRUB_ERR_FILE_NOT_FOUND; + } + + return GRUB_ERR_NONE; +} + +static grub_err_t +grub_protect_tpm2_close_device (void) +{ + int err; + + if (grub_protector_tpm2_fd == -1) + return GRUB_ERR_NONE; + + err = close (grub_protector_tpm2_fd); + if (err) + { + fprintf (stderr, _("Could not close TPM device (Error: %u).\n"), errno); + return GRUB_ERR_IO; + } + + grub_protector_tpm2_fd = -1; + return GRUB_ERR_NONE; +} + +static grub_err_t +grub_protect_tpm2_get_policy_digest (struct grub_protect_args *args, + TPM2B_DIGEST *digest) +{ + TPM_RC rc; + TPML_PCR_SELECTION pcr_sel = { + .count = 1, + .pcrSelections = { + { + .hash = args->tpm2_bank, + .sizeOfSelect = 3, + .pcrSelect = { 0 } + }, + } + }; + TPML_PCR_SELECTION pcr_sel_out = { 0 }; + TPML_DIGEST pcr_values = { 0 }; + grub_uint8_t *pcr_digest; + grub_size_t pcr_digest_len; + grub_uint8_t *pcr_concat; + grub_size_t pcr_concat_len; + grub_uint8_t *pcr_cursor; + const gcry_md_spec_t *hash_spec; + TPM2B_NONCE nonce = { 0 }; + TPM2B_ENCRYPTED_SECRET salt = { 0 }; + TPMT_SYM_DEF symmetric = { 0 }; + TPMI_SH_AUTH_SESSION session = 0; + TPM2B_DIGEST pcr_digest_in = { + .size = TPM_SHA256_DIGEST_SIZE, + .buffer = { 0 } + }; + TPM2B_DIGEST policy_digest = { 0 }; + grub_uint8_t i; + grub_err_t err; + + /* PCR Read */ + for (i = 0; i < args->tpm2_pcr_count; i++) + pcr_sel + .pcrSelections[0] + .pcrSelect[TPM2_PCR_TO_SELECT(args->tpm2_pcrs[i])] + |= TPM2_PCR_TO_BIT(args->tpm2_pcrs[i]); + + rc = TPM2_PCR_Read (NULL, &pcr_sel, NULL, &pcr_sel_out, &pcr_values, NULL); + if (rc != TPM_RC_SUCCESS) + { + fprintf (stderr, _("Failed to read PCRs (TPM error: 0x%x).\n"), rc); + return GRUB_ERR_BAD_DEVICE; + } + + if ((pcr_sel_out.count != pcr_sel.count) || + (pcr_sel.pcrSelections[0].sizeOfSelect != + pcr_sel_out.pcrSelections[0].sizeOfSelect)) + { + fprintf (stderr, _("Could not read all the specified PCRs.\n")); + return GRUB_ERR_BAD_DEVICE; + } + + /* Compute PCR Digest */ + switch (args->tpm2_bank) + { + case TPM_ALG_SHA1: + pcr_digest_len = TPM_SHA1_DIGEST_SIZE; + hash_spec = GRUB_MD_SHA1; + break; + case TPM_ALG_SHA256: + pcr_digest_len = TPM_SHA256_DIGEST_SIZE; + hash_spec = GRUB_MD_SHA256; + break; + default: + return GRUB_ERR_BAD_ARGUMENT; + } + + pcr_digest = grub_malloc (pcr_digest_len); + if (!pcr_digest) + { + fprintf (stderr, _("Failed to allocate PCR digest buffer.\n")); + return GRUB_ERR_OUT_OF_MEMORY; + } + + pcr_concat_len = pcr_digest_len * args->tpm2_pcr_count; + pcr_concat = grub_malloc (pcr_concat_len); + if (!pcr_concat) + { + err = GRUB_ERR_OUT_OF_MEMORY; + fprintf (stderr, _("Failed to allocate PCR concatenation buffer.\n")); + goto exit1; + } + + pcr_cursor = pcr_concat; + for (i = 0; i < args->tpm2_pcr_count; i++) + { + if (pcr_values.digests[i].size != pcr_digest_len) + { + fprintf (stderr, + _("Bad PCR value size: expected %lu bytes but got %u bytes.\n"), + pcr_digest_len, pcr_values.digests[i].size); + goto exit2; + } + + grub_memcpy (pcr_cursor, pcr_values.digests[i].buffer, pcr_digest_len); + pcr_cursor += pcr_digest_len; + } + + grub_crypto_hash (hash_spec, pcr_digest, pcr_concat, pcr_concat_len); + + /* Start Trial Session */ + nonce.size = TPM_SHA256_DIGEST_SIZE; + symmetric.algorithm = TPM_ALG_NULL; + + rc = TPM2_StartAuthSession (TPM_RH_NULL, TPM_RH_NULL, 0, &nonce, &salt, + TPM_SE_TRIAL, &symmetric, TPM_ALG_SHA256, + &session, NULL, 0); + if (rc != TPM_RC_SUCCESS) + { + fprintf (stderr, + _("Failed to start trial policy session (TPM error: 0x%x).\n"), + rc); + err = GRUB_ERR_BAD_DEVICE; + goto exit2; + } + + /* PCR Policy */ + memcpy (pcr_digest_in.buffer, pcr_digest, TPM_SHA256_DIGEST_SIZE); + + rc = TPM2_PolicyPCR (session, NULL, &pcr_digest_in, &pcr_sel, NULL); + if (rc != TPM_RC_SUCCESS) + { + fprintf (stderr, _("Failed to submit PCR policy (TPM error: 0x%x).\n"), + rc); + err = GRUB_ERR_BAD_DEVICE; + goto exit3; + } + + /* Retrieve Policy Digest */ + rc = TPM2_PolicyGetDigest (session, NULL, &policy_digest, NULL); + if (rc != TPM_RC_SUCCESS) + { + fprintf (stderr, _("Failed to get policy digest (TPM error: 0x%x).\n"), + rc); + err = GRUB_ERR_BAD_DEVICE; + goto exit3; + } + + /* Epilogue */ + *digest = policy_digest; + err = GRUB_ERR_NONE; + +exit3: + TPM2_FlushContext (session); + +exit2: + grub_free (pcr_concat); + +exit1: + grub_free (pcr_digest); + + return err; +} + +static grub_err_t +grub_protect_tpm2_get_srk (struct grub_protect_args *args, TPM_HANDLE *srk) +{ + TPM_RC rc; + TPM2B_PUBLIC public; + TPMS_AUTH_COMMAND authCommand = { 0 }; + TPM2B_SENSITIVE_CREATE inSensitive = { 0 }; + TPM2B_PUBLIC inPublic = { 0 }; + TPM2B_DATA outsideInfo = { 0 }; + TPML_PCR_SELECTION creationPcr = { 0 }; + TPM2B_PUBLIC outPublic = { 0 }; + TPM2B_CREATION_DATA creationData = { 0 }; + TPM2B_DIGEST creationHash = { 0 }; + TPMT_TK_CREATION creationTicket = { 0 }; + TPM2B_NAME srkName = { 0 }; + TPM_HANDLE srkHandle; + + /* Find SRK */ + rc = TPM2_ReadPublic (args->tpm2_srk, NULL, &public); + if (rc == TPM_RC_SUCCESS) + { + if (args->tpm2_persist) + fprintf (stderr, + _("Warning: --tpm2-persist was specified but the SRK already " + "exists on the TPM. Continuing anyway...\n")); + + *srk = TPM2_SRK_HANDLE; + return GRUB_ERR_NONE; + } + + /* The handle exists but its public area could not be read. */ + if ((rc & ~TPM_RC_N_MASK) != TPM_RC_HANDLE) + { + fprintf (stderr, + _("The SRK exists on the TPM but its public area cannot be read " + "(TPM error: 0x%x).\n"), rc); + return GRUB_ERR_BAD_DEVICE; + } + + /* Create SRK */ + authCommand.sessionHandle = TPM_RS_PW; + inPublic.publicArea.type = args->tpm2_asymmetric; + inPublic.publicArea.nameAlg = TPM_ALG_SHA256; + inPublic.publicArea.objectAttributes.restricted = 1; + inPublic.publicArea.objectAttributes.userWithAuth = 1; + inPublic.publicArea.objectAttributes.decrypt = 1; + inPublic.publicArea.objectAttributes.fixedTPM = 1; + inPublic.publicArea.objectAttributes.fixedParent = 1; + inPublic.publicArea.objectAttributes.sensitiveDataOrigin = 1; + inPublic.publicArea.objectAttributes.noDA = 1; + + switch (args->tpm2_asymmetric) + { + case TPM_ALG_RSA: + inPublic.publicArea.parameters.rsaDetail.symmetric.algorithm = TPM_ALG_AES; + inPublic.publicArea.parameters.rsaDetail.symmetric.keyBits.aes = 128; + inPublic.publicArea.parameters.rsaDetail.symmetric.mode.aes = TPM_ALG_CFB; + inPublic.publicArea.parameters.rsaDetail.scheme.scheme = TPM_ALG_NULL; + inPublic.publicArea.parameters.rsaDetail.keyBits = 2048; + inPublic.publicArea.parameters.rsaDetail.exponent = 0; + break; + + case TPM_ALG_ECC: + inPublic.publicArea.parameters.eccDetail.symmetric.algorithm = TPM_ALG_AES; + inPublic.publicArea.parameters.eccDetail.symmetric.keyBits.aes = 128; + inPublic.publicArea.parameters.eccDetail.symmetric.mode.aes = TPM_ALG_CFB; + inPublic.publicArea.parameters.eccDetail.scheme.scheme = TPM_ALG_NULL; + inPublic.publicArea.parameters.eccDetail.curveID = TPM_ECC_NIST_P256; + inPublic.publicArea.parameters.eccDetail.kdf.scheme = TPM_ALG_NULL; + break; + + default: + return GRUB_ERR_BAD_ARGUMENT; + } + + rc = TPM2_CreatePrimary (TPM_RH_OWNER, &authCommand, &inSensitive, &inPublic, + &outsideInfo, &creationPcr, &srkHandle, &outPublic, + &creationData, &creationHash, &creationTicket, + &srkName, NULL); + if (rc != TPM_RC_SUCCESS) + { + fprintf (stderr, _("Failed to create SRK (TPM error: 0x%x).\n"), rc); + return GRUB_ERR_BAD_DEVICE; + } + + /* Persist SRK */ + if (args->tpm2_persist) + { + rc = TPM2_EvictControl (TPM_RH_OWNER, srkHandle, args->tpm2_srk, + &authCommand, NULL); + if (rc == TPM_RC_SUCCESS) + { + TPM2_FlushContext (srkHandle); + srkHandle = args->tpm2_srk; + } + else + fprintf (stderr, + _("Warning: Failed to persist SRK (TPM error: 0x%x\n). " + "Continuing anyway...\n"), rc); + } + + /* Epilogue */ + *srk = srkHandle; + + return GRUB_ERR_NONE; +} + +static grub_err_t +grub_protect_tpm2_seal (TPM2B_DIGEST *policyDigest, TPM_HANDLE srk, + grub_uint8_t *clearText, grub_size_t clearTextLength, + TPM2_SEALED_KEY *sealed_key) +{ + TPM_RC rc; + TPMS_AUTH_COMMAND authCommand = { 0 }; + TPM2B_SENSITIVE_CREATE inSensitive = { 0 }; + TPM2B_PUBLIC inPublic = { 0 }; + TPM2B_DATA outsideInfo = { 0 }; + TPML_PCR_SELECTION pcr_sel = { 0 }; + TPM2B_PRIVATE outPrivate = { 0 }; + TPM2B_PUBLIC outPublic = { 0 }; + + /* Seal Data */ + authCommand.sessionHandle = TPM_RS_PW; + + inSensitive.sensitive.data.size = clearTextLength; + memcpy(inSensitive.sensitive.data.buffer, clearText, clearTextLength); + + inPublic.publicArea.type = TPM_ALG_KEYEDHASH; + inPublic.publicArea.nameAlg = TPM_ALG_SHA256; + inPublic.publicArea.parameters.keyedHashDetail.scheme.scheme = TPM_ALG_NULL; + inPublic.publicArea.authPolicy = *policyDigest; + + rc = TPM2_Create (srk, &authCommand, &inSensitive, &inPublic, &outsideInfo, + &pcr_sel, &outPrivate, &outPublic, NULL, NULL, NULL, NULL); + if (rc != TPM_RC_SUCCESS) + { + fprintf (stderr, _("Failed to seal key (TPM error: 0x%x).\n"), rc); + return GRUB_ERR_BAD_DEVICE; + } + + /* Epilogue */ + sealed_key->public = outPublic; + sealed_key->private = outPrivate; + + return GRUB_ERR_NONE; +} + +static grub_err_t +grub_protect_tpm2_export_sealed_key (const char *filepath, + TPM2_SEALED_KEY *sealed_key) +{ + grub_err_t err; + struct grub_tpm2_buffer buf; + + grub_tpm2_buffer_init (&buf); + grub_tpm2_mu_TPM2B_PUBLIC_Marshal (&buf, &sealed_key->public); + grub_tpm2_mu_TPM2B_Marshal (&buf, sealed_key->private.size, + sealed_key->private.buffer); + if (buf.error) + return GRUB_ERR_BAD_ARGUMENT; + + err = grub_protect_write_file (filepath, buf.data, buf.size); + if (err) + fprintf (stderr, _("Could not write sealed key file (Error: %u).\n"), + errno); + + return err; +} + +static grub_err_t +grub_protect_tpm2_add (struct grub_protect_args *args) +{ + grub_err_t err; + grub_uint8_t *key; + grub_size_t key_size; + TPM_HANDLE srk; + TPM2B_DIGEST policy_digest; + TPM2_SEALED_KEY sealed_key; + char *grub_drive = NULL; + + grub_protect_get_grub_drive_for_file (args->tpm2_outfile, &grub_drive); + + err = grub_protect_tpm2_open_device (args->tpm2_device); + if (err) + return err; + + err = grub_protect_read_file (args->tpm2_keyfile, (void **)&key, &key_size); + if (err) + goto exit1; + + if (key_size > TPM_MAX_SYM_DATA) + { + fprintf (stderr, + _("Input key is too long, maximum allowed size is %u bytes.\n"), + TPM_MAX_SYM_DATA); + return GRUB_ERR_OUT_OF_RANGE; + } + + err = grub_protect_tpm2_get_srk (args, &srk); + if (err) + goto exit2; + + err = grub_protect_tpm2_get_policy_digest (args, &policy_digest); + if (err) + goto exit3; + + err = grub_protect_tpm2_seal (&policy_digest, srk, key, key_size, + &sealed_key); + if (err) + goto exit3; + + err = grub_protect_tpm2_export_sealed_key (args->tpm2_outfile, &sealed_key); + if (err) + goto exit3; + + if (grub_drive) + { + printf (_("GRUB drive for the sealed key file: %s\n"), grub_drive); + grub_free (grub_drive); + } + else + { + fprintf (stderr, + _("Warning: Could not determine GRUB drive for sealed key " + "file.\n")); + err = GRUB_ERR_NONE; + } + +exit3: + TPM2_FlushContext (srk); + +exit2: + grub_free (key); + +exit1: + grub_protect_tpm2_close_device (); + + return err; +} + +static grub_err_t +grub_protect_tpm2_remove (struct grub_protect_args *args) +{ + TPM_RC rc; + TPM2B_PUBLIC public; + TPMS_AUTH_COMMAND authCommand = { 0 }; + grub_err_t err; + + if (!args->tpm2_evict) + { + printf (_("--tpm2-evict not specified, nothing to do.\n")); + return GRUB_ERR_NONE; + } + + err = grub_protect_tpm2_open_device (args->tpm2_device); + if (err) + return err; + + /* Find SRK */ + rc = TPM2_ReadPublic (args->tpm2_srk, NULL, &public); + if (rc != TPM_RC_SUCCESS) + { + fprintf (stderr, _("SRK with handle 0x%x not found.\n"), args->tpm2_srk); + err = GRUB_ERR_BAD_ARGUMENT; + goto exit1; + } + + /* Evict SRK */ + authCommand.sessionHandle = TPM_RS_PW; + + rc = TPM2_EvictControl (TPM_RH_OWNER, args->tpm2_srk, args->tpm2_srk, + &authCommand, NULL); + if (rc != TPM_RC_SUCCESS) + { + fprintf (stderr, + _("Failed to evict SRK with handle 0x%x (TPM Error: 0x%x).\n"), + args->tpm2_srk, rc); + err = GRUB_ERR_BAD_DEVICE; + goto exit2; + } + + err = GRUB_ERR_NONE; + +exit2: + TPM2_FlushContext (args->tpm2_srk); + +exit1: + grub_protect_tpm2_close_device (); + + return GRUB_ERR_NONE; +} + +static grub_err_t +grub_protect_tpm2_run (struct grub_protect_args *args) +{ + switch (args->action) + { + case GRUB_PROTECT_ACTION_ADD: + return grub_protect_tpm2_add (args); + + case GRUB_PROTECT_ACTION_REMOVE: + return grub_protect_tpm2_remove (args); + + default: + return GRUB_ERR_BAD_ARGUMENT; + } +} + +static grub_err_t +grub_protect_tpm2_args_verify (struct grub_protect_args *args) +{ + switch (args->action) + { + case GRUB_PROTECT_ACTION_ADD: + if (args->args & GRUB_PROTECT_ARG_TPM2_EVICT) + { + fprintf (stderr, + _("--tpm2-evict is invalid when --action is 'add'.\n")); + return GRUB_ERR_BAD_ARGUMENT; + } + + if (!args->tpm2_keyfile) + { + fprintf (stderr, _("--tpm2-keyfile must be specified.\n")); + return GRUB_ERR_BAD_ARGUMENT; + } + + if (!args->tpm2_outfile) + { + fprintf (stderr, _("--tpm2-outfile must be specified.\n")); + return GRUB_ERR_BAD_ARGUMENT; + } + + if (!args->tpm2_device) + args->tpm2_device = "/dev/tpm0"; + + if (!args->tpm2_pcr_count) + { + args->tpm2_pcrs[0] = 7; + args->tpm2_pcr_count = 1; + } + + if (!args->tpm2_srk) + args->tpm2_srk = TPM2_SRK_HANDLE; + + if (!args->tpm2_asymmetric) + args->tpm2_asymmetric = TPM_ALG_RSA; + + if (!args->tpm2_bank) + args->tpm2_bank = TPM_ALG_SHA256; + + break; + + case GRUB_PROTECT_ACTION_REMOVE: + if (args->args & GRUB_PROTECT_ARG_TPM2_ASYMMETRIC) + { + fprintf (stderr, + _("--tpm2-asymmetric is invalid when --action is 'remove'.\n")); + return GRUB_ERR_BAD_ARGUMENT; + } + + if (args->args & GRUB_PROTECT_ARG_TPM2_BANK) + { + fprintf (stderr, + _("--tpm2-bank is invalid when --action is 'remove'.\n")); + return GRUB_ERR_BAD_ARGUMENT; + } + + if (args->args & GRUB_PROTECT_ARG_TPM2_KEYFILE) + { + fprintf (stderr, + _("--tpm2-keyfile is invalid when --action is 'remove'.\n")); + return GRUB_ERR_BAD_ARGUMENT; + } + + if (args->args & GRUB_PROTECT_ARG_TPM2_OUTFILE) + { + fprintf (stderr, + _("--tpm2-outfile is invalid when --action is 'remove'.\n")); + return GRUB_ERR_BAD_ARGUMENT; + } + + if (args->args & GRUB_PROTECT_ARG_TPM2_PCRS) + { + fprintf (stderr, + _("--tpm2-pcrs is invalid when --action is 'remove'.\n")); + return GRUB_ERR_BAD_ARGUMENT; + } + + if (args->args & GRUB_PROTECT_ARG_TPM2_PERSIST) + { + fprintf (stderr, + _("--tpm2-persist is invalid when --action is 'remove'.\n")); + return GRUB_ERR_BAD_ARGUMENT; + } + + if (!args->tpm2_device) + args->tpm2_device = "/dev/tpm0"; + + if (!args->tpm2_srk) + args->tpm2_srk = TPM2_SRK_HANDLE; + + break; + + default: + fprintf (stderr, + _("The TPM2 key protector only supports the following actions: " + "add, remove.\n")); + return GRUB_ERR_BAD_ARGUMENT; + } + + return GRUB_ERR_NONE; +} + +static error_t +grub_protect_argp_parser (int key, char *arg, struct argp_state *state) +{ + grub_err_t err; + struct grub_protect_args *args = state->input; + + switch (key) + { + case GRUB_PROTECT_OPT_ACTION: + if (args->args & GRUB_PROTECT_ARG_ACTION) + { + fprintf (stderr, _("--action|-a can only be specified once.\n")); + return EINVAL; + } + + if (grub_strcmp (arg, "add") == 0) + args->action = GRUB_PROTECT_ACTION_ADD; + else if (grub_strcmp (arg, "remove") == 0) + args->action = GRUB_PROTECT_ACTION_REMOVE; + else + { + fprintf (stderr, _("'%s' is not a valid action.\n"), arg); + return EINVAL; + } + + args->args |= GRUB_PROTECT_ARG_ACTION; + break; + + case GRUB_PROTECT_OPT_PROTECTOR: + if (args->args & GRUB_PROTECT_ARG_PROTECTOR) + { + fprintf (stderr, _("--protector|-p can only be specified once.\n")); + return EINVAL; + } + + if (grub_strcmp (arg, "tpm2") == 0) + args->protector = GRUB_PROTECT_TYPE_TPM2; + else + { + fprintf (stderr, _("'%s' is not a valid protector.\n"), arg); + return EINVAL; + } + + args->args |= GRUB_PROTECT_ARG_PROTECTOR; + break; + + case GRUB_PROTECT_OPT_TPM2_DEVICE: + if (args->args & GRUB_PROTECT_ARG_TPM2_DEVICE) + { + fprintf (stderr, _("--tpm2-device can only be specified once.\n")); + return EINVAL; + } + + args->tpm2_device = xstrdup(arg); + args->args |= GRUB_PROTECT_ARG_TPM2_DEVICE; + break; + + case GRUB_PROTECT_OPT_TPM2_PCRS: + if (args->args & GRUB_PROTECT_ARG_TPM2_PCRS) + { + fprintf (stderr, _("--tpm2-pcrs can only be specified once.\n")); + return EINVAL; + } + + err = grub_tpm2_protector_parse_pcrs (arg, args->tpm2_pcrs, + &args->tpm2_pcr_count); + if (err) + { + if (grub_errno) + grub_print_error (); + return EINVAL; + } + + args->args |= GRUB_PROTECT_ARG_TPM2_PCRS; + break; + + case GRUB_PROTECT_OPT_TPM2_SRK: + if (args->args & GRUB_PROTECT_ARG_TPM2_SRK) + { + fprintf (stderr, _("--tpm2-srk can only be specified once.\n")); + return EINVAL; + } + + err = grub_tpm2_protector_parse_tpm_handle (arg, &args->tpm2_srk); + if (err) + { + if (grub_errno) + grub_print_error (); + return EINVAL; + } + + args->args |= GRUB_PROTECT_ARG_TPM2_SRK; + break; + + case GRUB_PROTECT_OPT_TPM2_ASYMMETRIC: + if (args->args & GRUB_PROTECT_ARG_TPM2_ASYMMETRIC) + { + fprintf (stderr, _("--tpm2-asymmetric can only be specified once.\n")); + return EINVAL; + } + + err = grub_tpm2_protector_parse_asymmetric (arg, &args->tpm2_asymmetric); + if (err) + { + if (grub_errno) + grub_print_error (); + return EINVAL; + } + + args->args |= GRUB_PROTECT_ARG_TPM2_ASYMMETRIC; + break; + + case GRUB_PROTECT_OPT_TPM2_BANK: + if (args->args & GRUB_PROTECT_ARG_TPM2_BANK) + { + fprintf (stderr, _("--tpm2-bank can only be specified once.\n")); + return EINVAL; + } + + err = grub_tpm2_protector_parse_bank (arg, &args->tpm2_bank); + if (err) + { + if (grub_errno) + grub_print_error (); + return EINVAL; + } + + args->args |= GRUB_PROTECT_ARG_TPM2_BANK; + break; + + case GRUB_PROTECT_OPT_TPM2_KEYFILE: + if (args->args & GRUB_PROTECT_ARG_TPM2_KEYFILE) + { + fprintf (stderr, _("--tpm2-keyfile can only be specified once.\n")); + return EINVAL; + } + + args->tpm2_keyfile = xstrdup(arg); + args->args |= GRUB_PROTECT_ARG_TPM2_KEYFILE; + break; + + case GRUB_PROTECT_OPT_TPM2_OUTFILE: + if (args->args & GRUB_PROTECT_ARG_TPM2_OUTFILE) + { + fprintf (stderr, _("--tpm2-outfile can only be specified once.\n")); + return EINVAL; + } + + args->tpm2_outfile = xstrdup(arg); + args->args |= GRUB_PROTECT_ARG_TPM2_OUTFILE; + break; + + case GRUB_PROTECT_OPT_TPM2_PERSIST: + if (args->args & GRUB_PROTECT_ARG_TPM2_PERSIST) + { + fprintf (stderr, _("--tpm2-persist can only be specified once.\n")); + return EINVAL; + } + + args->tpm2_persist = 1; + args->args |= GRUB_PROTECT_ARG_TPM2_PERSIST; + break; + + case GRUB_PROTECT_OPT_TPM2_EVICT: + if (args->args & GRUB_PROTECT_ARG_TPM2_EVICT) + { + fprintf (stderr, _("--tpm2-evict can only be specified once.\n")); + return EINVAL; + } + + args->tpm2_evict = 1; + args->args |= GRUB_PROTECT_ARG_TPM2_EVICT; + break; + + default: + return ARGP_ERR_UNKNOWN; + } + + return 0; +} + +static grub_err_t +grub_protect_args_verify (struct grub_protect_args *args) +{ + if (args->action == GRUB_PROTECT_ACTION_ERROR) + { + fprintf (stderr, "--action is mandatory.\n"); + return GRUB_ERR_BAD_ARGUMENT; + } + + /* At the moment, the only configurable key protector is the TPM2 one, so it + * is the only key protector supported by this tool. */ + if (args->protector != GRUB_PROTECT_TYPE_TPM2) + { + fprintf (stderr, + _("--protector is mandatory and only 'tpm2' is currently " + "supported.\n")); + return GRUB_ERR_BAD_ARGUMENT; + } + + switch (args->protector) + { + case GRUB_PROTECT_TYPE_TPM2: + return grub_protect_tpm2_args_verify (args); + default: + return GRUB_ERR_BAD_ARGUMENT; + } + + return GRUB_ERR_NONE; +} + +static grub_err_t +grub_protect_dispatch (struct grub_protect_args *args) +{ + switch (args->protector) + { + case GRUB_PROTECT_TYPE_TPM2: + return grub_protect_tpm2_run (args); + default: + return GRUB_ERR_BAD_ARGUMENT; + } +} + +static void +grub_protect_init (int *argc, char **argv[]) +{ + grub_util_host_init (argc, argv); + + grub_util_biosdisk_init (NULL); + + grub_init_all (); + grub_gcry_init_all (); + + grub_lvm_fini (); + grub_mdraid09_fini (); + grub_mdraid1x_fini (); + grub_diskfilter_fini (); + grub_diskfilter_init (); + grub_mdraid09_init (); + grub_mdraid1x_init (); + grub_lvm_init (); +} + +static void +grub_protect_fini (void) +{ + grub_gcry_fini_all (); + grub_fini_all (); + grub_util_biosdisk_fini (); +} + +static struct argp grub_protect_argp = +{ + .options = grub_protect_options, + .parser = grub_protect_argp_parser, + .args_doc = NULL, + .doc = + N_("Protect a cleartext key using a GRUB key protector that can retrieve " + "the key during boot to unlock fully-encrypted disks automatically."), + .children = NULL, + .help_filter = NULL, + .argp_domain = NULL +}; + +int +main (int argc, char *argv[]) +{ + grub_err_t err; + struct grub_protect_args args = { 0 }; + + if (argp_parse (&grub_protect_argp, argc, argv, 0, 0, &args) != 0) + { + fprintf (stderr, _("Could not parse arguments.\n")); + return GRUB_ERR_BAD_ARGUMENT; + } + + grub_protect_init (&argc, &argv); + + err = grub_protect_args_verify (&args); + if (err) + goto exit; + + err = grub_protect_dispatch (&args); + if (err) + goto exit; + +exit: + grub_protect_fini (); + + return err; +} -- 2.34.1
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