From 7ce7b7889ce73174a0d8091978254ecf2d2e205f Mon Sep 17 00:00:00 2001 From: Hernan Gatta Date: Tue, 1 Feb 2022 05:02:56 -0800 Subject: [PATCH 4/5] cryptodisk: Support key protectors Add a new parameter to cryptomount to support the key protectors framework: -P. The parameter is used to automatically retrieve a key from specified key protectors. The parameter may be repeated to specify any number of key protectors. These are tried in order until one provides a usable key for any given disk. Signed-off-by: Hernan Gatta Signed-off-by: Michael Chang Signed-off-by: Gary Lin Reviewed-by: Glenn Washburn Reviewed-by: Stefan Berger --- Makefile.util.def | 1 + grub-core/disk/cryptodisk.c | 172 +++++++++++++++++++++++++++++------- include/grub/cryptodisk.h | 16 ++++ 3 files changed, 158 insertions(+), 31 deletions(-) diff --git a/Makefile.util.def b/Makefile.util.def index 3b9435307..252d70af2 100644 --- a/Makefile.util.def +++ b/Makefile.util.def @@ -40,6 +40,7 @@ library = { common = grub-core/disk/luks.c; common = grub-core/disk/luks2.c; common = grub-core/disk/geli.c; + common = grub-core/disk/key_protector.c; common = grub-core/disk/cryptodisk.c; common = grub-core/disk/AFSplitter.c; common = grub-core/lib/pbkdf2.c; diff --git a/grub-core/disk/cryptodisk.c b/grub-core/disk/cryptodisk.c index 2246af51b..b7648ffb7 100644 --- a/grub-core/disk/cryptodisk.c +++ b/grub-core/disk/cryptodisk.c @@ -26,6 +26,7 @@ #include #include #include +#include #ifdef GRUB_UTIL #include @@ -44,7 +45,8 @@ enum OPTION_KEYFILE, OPTION_KEYFILE_OFFSET, OPTION_KEYFILE_SIZE, - OPTION_HEADER + OPTION_HEADER, + OPTION_PROTECTOR }; static const struct grub_arg_option options[] = @@ -58,6 +60,8 @@ static const struct grub_arg_option options[] = {"keyfile-offset", 'O', 0, N_("Key file offset (bytes)"), 0, ARG_TYPE_INT}, {"keyfile-size", 'S', 0, N_("Key file data size (bytes)"), 0, ARG_TYPE_INT}, {"header", 'H', 0, N_("Read header from file"), 0, ARG_TYPE_STRING}, + {"protector", 'P', GRUB_ARG_OPTION_REPEATABLE, + N_("Unlock volume(s) using key protector(s)."), 0, ARG_TYPE_STRING}, {0, 0, 0, 0, 0, 0} }; @@ -1061,6 +1065,7 @@ grub_cryptodisk_scan_device_real (const char *name, grub_err_t ret = GRUB_ERR_NONE; grub_cryptodisk_t dev; grub_cryptodisk_dev_t cr; + int i; struct cryptodisk_read_hook_ctx read_hook_data = {0}; int askpass = 0; char *part = NULL; @@ -1113,41 +1118,112 @@ grub_cryptodisk_scan_device_real (const char *name, goto error_no_close; if (!dev) continue; + break; + } - if (!cargs->key_len) - { - /* Get the passphrase from the user, if no key data. */ - askpass = 1; - part = grub_partition_get_name (source->partition); - grub_printf_ (N_("Enter passphrase for %s%s%s (%s): "), source->name, - source->partition != NULL ? "," : "", - part != NULL ? part : N_("UNKNOWN"), - dev->uuid); - grub_free (part); - - cargs->key_data = grub_malloc (GRUB_CRYPTODISK_MAX_PASSPHRASE); - if (cargs->key_data == NULL) - goto error_no_close; - - if (!grub_password_get ((char *) cargs->key_data, GRUB_CRYPTODISK_MAX_PASSPHRASE)) - { - grub_error (GRUB_ERR_BAD_ARGUMENT, "passphrase not supplied"); - goto error; - } - cargs->key_len = grub_strlen ((char *) cargs->key_data); - } + if (dev == NULL) + { + grub_error (GRUB_ERR_BAD_MODULE, + "no cryptodisk module can handle this device"); + goto error_no_close; + } - ret = cr->recover_key (source, dev, cargs); - if (ret != GRUB_ERR_NONE) - goto error; + if (cargs->protectors) + { + for (i = 0; cargs->protectors[i]; i++) + { + if (cargs->key_cache[i].invalid) + continue; + + if (cargs->key_cache[i].key == NULL) + { + ret = grub_key_protector_recover_key (cargs->protectors[i], + &cargs->key_cache[i].key, + &cargs->key_cache[i].key_len); + if (ret != GRUB_ERR_NONE) + { + if (grub_errno) + { + grub_print_error (); + grub_errno = GRUB_ERR_NONE; + } + + grub_dprintf ("cryptodisk", + "failed to recover a key from key protector " + "%s, will not try it again for any other " + "disks, if any, during this invocation of " + "cryptomount\n", + cargs->protectors[i]); + + cargs->key_cache[i].invalid = 1; + continue; + } + } + + cargs->key_data = cargs->key_cache[i].key; + cargs->key_len = cargs->key_cache[i].key_len; + + ret = cr->recover_key (source, dev, cargs); + if (ret != GRUB_ERR_NONE) + { + part = grub_partition_get_name (source->partition); + grub_dprintf ("cryptodisk", + "recovered a key from key protector %s but it " + "failed to unlock %s%s%s (%s)\n", + cargs->protectors[i], source->name, + source->partition != NULL ? "," : "", + part != NULL ? part : N_("UNKNOWN"), dev->uuid); + grub_free (part); + continue; + } + else + { + ret = grub_cryptodisk_insert (dev, name, source); + if (ret != GRUB_ERR_NONE) + goto error; + goto cleanup; + } + } - ret = grub_cryptodisk_insert (dev, name, source); - if (ret != GRUB_ERR_NONE) + part = grub_partition_get_name (source->partition); + grub_error (GRUB_ERR_ACCESS_DENIED, + N_("no key protector provided a usable key for %s%s%s (%s)"), + source->name, source->partition != NULL ? "," : "", + part != NULL ? part : N_("UNKNOWN"), dev->uuid); + grub_free (part); goto error; + } + + if (!cargs->key_len) + { + /* Get the passphrase from the user, if no key data. */ + askpass = 1; + part = grub_partition_get_name (source->partition); + grub_printf_ (N_("Enter passphrase for %s%s%s (%s): "), source->name, + source->partition != NULL ? "," : "", + part != NULL ? part : N_("UNKNOWN"), dev->uuid); + grub_free (part); + + cargs->key_data = grub_malloc (GRUB_CRYPTODISK_MAX_PASSPHRASE); + if (cargs->key_data == NULL) + goto error; + + if (!grub_password_get ((char *) cargs->key_data, GRUB_CRYPTODISK_MAX_PASSPHRASE)) + { + grub_error (GRUB_ERR_BAD_ARGUMENT, "passphrase not supplied"); + goto error; + } + cargs->key_len = grub_strlen ((char *) cargs->key_data); + } + + ret = cr->recover_key (source, dev, cargs); + if (ret != GRUB_ERR_NONE) + goto error; + + ret = grub_cryptodisk_insert (dev, name, source); + if (ret != GRUB_ERR_NONE) + goto error; - goto cleanup; - } - grub_error (GRUB_ERR_BAD_MODULE, "no cryptodisk module can handle this device"); goto cleanup; error: @@ -1259,6 +1335,20 @@ grub_cryptodisk_scan_device (const char *name, return ret; } +static void +grub_cryptodisk_clear_key_cache (struct grub_cryptomount_args *cargs) +{ + int i; + + if (cargs->key_cache == NULL || cargs->protectors == NULL) + return; + + for (i = 0; cargs->protectors[i]; i++) + grub_free (cargs->key_cache[i].key); + + grub_free (cargs->key_cache); +} + static grub_err_t grub_cmd_cryptomount (grub_extcmd_context_t ctxt, int argc, char **args) { @@ -1271,6 +1361,10 @@ grub_cmd_cryptomount (grub_extcmd_context_t ctxt, int argc, char **args) if (grub_cryptodisk_list == NULL) return grub_error (GRUB_ERR_BAD_MODULE, "no cryptodisk modules loaded"); + if (state[OPTION_PASSWORD].set && state[OPTION_PROTECTOR].set) /* password and key protector */ + return grub_error (GRUB_ERR_BAD_ARGUMENT, + "a password and a key protector cannot both be set"); + if (state[OPTION_PASSWORD].set) /* password */ { cargs.key_data = (grub_uint8_t *) state[OPTION_PASSWORD].arg; @@ -1363,6 +1457,15 @@ grub_cmd_cryptomount (grub_extcmd_context_t ctxt, int argc, char **args) return grub_errno; } + if (state[OPTION_PROTECTOR].set) /* key protector(s) */ + { + cargs.key_cache = grub_zalloc (state[OPTION_PROTECTOR].set * sizeof (*cargs.key_cache)); + if (cargs.key_cache == NULL) + return grub_error (GRUB_ERR_OUT_OF_MEMORY, + "no memory for key protector key cache"); + cargs.protectors = state[OPTION_PROTECTOR].args; + } + if (state[OPTION_UUID].set) /* uuid */ { int found_uuid; @@ -1371,6 +1474,7 @@ grub_cmd_cryptomount (grub_extcmd_context_t ctxt, int argc, char **args) dev = grub_cryptodisk_get_by_uuid (args[0]); if (dev) { + grub_cryptodisk_clear_key_cache (&cargs); grub_dprintf ("cryptodisk", "already mounted as crypto%lu\n", dev->id); return GRUB_ERR_NONE; @@ -1379,6 +1483,7 @@ grub_cmd_cryptomount (grub_extcmd_context_t ctxt, int argc, char **args) cargs.check_boot = state[OPTION_BOOT].set; cargs.search_uuid = args[0]; found_uuid = grub_device_iterate (&grub_cryptodisk_scan_device, &cargs); + grub_cryptodisk_clear_key_cache (&cargs); if (found_uuid) return GRUB_ERR_NONE; @@ -1398,6 +1503,7 @@ grub_cmd_cryptomount (grub_extcmd_context_t ctxt, int argc, char **args) { cargs.check_boot = state[OPTION_BOOT].set; grub_device_iterate (&grub_cryptodisk_scan_device, &cargs); + grub_cryptodisk_clear_key_cache (&cargs); return GRUB_ERR_NONE; } else @@ -1421,6 +1527,7 @@ grub_cmd_cryptomount (grub_extcmd_context_t ctxt, int argc, char **args) disk = grub_disk_open (diskname); if (!disk) { + grub_cryptodisk_clear_key_cache (&cargs); if (disklast) *disklast = ')'; return grub_errno; @@ -1431,12 +1538,14 @@ grub_cmd_cryptomount (grub_extcmd_context_t ctxt, int argc, char **args) { grub_dprintf ("cryptodisk", "already mounted as crypto%lu\n", dev->id); grub_disk_close (disk); + grub_cryptodisk_clear_key_cache (&cargs); if (disklast) *disklast = ')'; return GRUB_ERR_NONE; } dev = grub_cryptodisk_scan_device_real (diskname, disk, &cargs); + grub_cryptodisk_clear_key_cache (&cargs); grub_disk_close (disk); if (disklast) @@ -1590,6 +1699,7 @@ GRUB_MOD_INIT (cryptodisk) cmd = grub_register_extcmd ("cryptomount", grub_cmd_cryptomount, 0, N_("[ [-p password] | [-k keyfile" " [-O keyoffset] [-S keysize] ] ] [-H file]" + " [-P protector [-P protector ...]]" " "), N_("Mount a crypto device."), options); grub_procfs_register ("luks_script", &luks_script); diff --git a/include/grub/cryptodisk.h b/include/grub/cryptodisk.h index d94df68b6..0b41e249e 100644 --- a/include/grub/cryptodisk.h +++ b/include/grub/cryptodisk.h @@ -70,6 +70,18 @@ typedef gcry_err_code_t (*grub_cryptodisk_rekey_func_t) (struct grub_cryptodisk *dev, grub_uint64_t zoneno); +struct grub_cryptomount_cached_key +{ + grub_uint8_t *key; + grub_size_t key_len; + + /* + * The key protector associated with this cache entry failed, so avoid it + * even if the cached entry (an instance of this structure) is empty. + */ + int invalid; +}; + struct grub_cryptomount_args { /* scan: Flag to indicate that only bootable volumes should be decrypted */ @@ -81,6 +93,10 @@ struct grub_cryptomount_args /* recover_key: Length of key_data */ grub_size_t key_len; grub_file_t hdr_file; + /* recover_key: Names of the key protectors to use (NULL-terminated) */ + char **protectors; + /* recover_key: Key cache to avoid invoking the same key protector twice */ + struct grub_cryptomount_cached_key *key_cache; }; typedef struct grub_cryptomount_args *grub_cryptomount_args_t; -- 2.35.3