/* SPDX-License-Identifier: LGPL-2.1-or-later */ #include "cryptenroll-wipe.h" #include "cryptenroll.h" #include "json.h" #include "memory-util.h" #include "parse-util.h" #include "set.h" #include "sort-util.h" static int find_all_slots(struct crypt_device *cd, Set *wipe_slots, Set *keep_slots) { int slot_max; assert(cd); assert(wipe_slots); assert_se((slot_max = crypt_keyslot_max(CRYPT_LUKS2)) > 0); /* Finds all currently assigned slots, and adds them to 'wipe_slots', except if listed already in 'keep_slots' */ for (int slot = 0; slot < slot_max; slot++) { crypt_keyslot_info status; /* No need to check this slot if we already know we want to wipe it or definitely keep it. */ if (set_contains(keep_slots, INT_TO_PTR(slot)) || set_contains(wipe_slots, INT_TO_PTR(slot))) continue; status = crypt_keyslot_status(cd, slot); if (!IN_SET(status, CRYPT_SLOT_ACTIVE, CRYPT_SLOT_ACTIVE_LAST)) continue; if (set_put(wipe_slots, INT_TO_PTR(slot)) < 0) return log_oom(); } return 0; } static int find_empty_passphrase_slots(struct crypt_device *cd, Set *wipe_slots, Set *keep_slots) { size_t vks; int r, slot_max; assert(cd); assert(wipe_slots); assert_se((slot_max = crypt_keyslot_max(CRYPT_LUKS2)) > 0); /* Finds all slots with an empty passphrase assigned (i.e. "") and adds them to 'wipe_slots', except * if listed already in 'keep_slots' */ r = crypt_get_volume_key_size(cd); if (r <= 0) return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Failed to determine LUKS volume key size"); vks = (size_t) r; for (int slot = 0; slot < slot_max; slot++) { _cleanup_(erase_and_freep) char *vk = NULL; crypt_keyslot_info status; /* No need to check this slot if we already know we want to wipe it or definitely keep it. */ if (set_contains(keep_slots, INT_TO_PTR(slot)) || set_contains(wipe_slots, INT_TO_PTR(slot))) continue; status = crypt_keyslot_status(cd, slot); if (!IN_SET(status, CRYPT_SLOT_ACTIVE, CRYPT_SLOT_ACTIVE_LAST)) continue; vk = malloc(vks); if (!vk) return log_oom(); r = crypt_volume_key_get(cd, slot, vk, &vks, "", 0); if (r < 0) { log_debug_errno(r, "Failed to acquire volume key from slot %i with empty password, ignoring: %m", slot); continue; } if (set_put(wipe_slots, INT_TO_PTR(r)) < 0) return log_oom(); } return 0; } static int find_slots_by_mask( struct crypt_device *cd, Set *wipe_slots, Set *keep_slots, unsigned by_mask) { _cleanup_(set_freep) Set *listed_slots = NULL; int r; assert(cd); assert(wipe_slots); if (by_mask == 0) return 0; /* Find all slots that are associated with a token of a type in the specified token type mask */ for (int token = 0; token < sym_crypt_token_max(CRYPT_LUKS2); token++) { _cleanup_(json_variant_unrefp) JsonVariant *v = NULL; JsonVariant *w, *z; EnrollType t; r = cryptsetup_get_token_as_json(cd, token, NULL, &v); if (IN_SET(r, -ENOENT, -EINVAL)) continue; if (r < 0) { log_warning_errno(r, "Failed to read JSON token data off disk, ignoring: %m"); continue; } w = json_variant_by_key(v, "type"); if (!w || !json_variant_is_string(w)) { log_warning("Token JSON data lacks type field, ignoring."); continue; } t = luks2_token_type_from_string(json_variant_string(w)); w = json_variant_by_key(v, "keyslots"); if (!w || !json_variant_is_array(w)) { log_warning("Token JSON data lacks keyslots field, ignoring."); continue; } JSON_VARIANT_ARRAY_FOREACH(z, w) { int slot; if (!json_variant_is_string(z)) { log_warning("Token JSON data's keyslot field is not an array of strings, ignoring."); continue; } r = safe_atoi(json_variant_string(z), &slot); if (r < 0) { log_warning_errno(r, "Token JSON data's keyslot filed is not an integer formatted as string, ignoring."); continue; } if (t >= 0 && (by_mask & (1U << t)) != 0) { /* Selected by token type */ if (set_put(wipe_slots, INT_TO_PTR(slot)) < 0) return log_oom(); } else if ((by_mask & (1U << ENROLL_PASSWORD)) != 0) { /* If we shall remove all plain password slots, let's maintain a list of * slots that are listed in any tokens, since those are *NOT* plain * passwords */ if (set_ensure_allocated(&listed_slots, NULL) < 0) return log_oom(); if (set_put(listed_slots, INT_TO_PTR(slot)) < 0) return log_oom(); } } } /* "password" slots are those which have no token assigned. If we shall remove those, iterate through * all slots and mark those for wiping that weren't listed in any token */ if ((by_mask & (1U << ENROLL_PASSWORD)) != 0) { int slot_max; assert_se((slot_max = crypt_keyslot_max(CRYPT_LUKS2)) > 0); for (int slot = 0; slot < slot_max; slot++) { crypt_keyslot_info status; /* No need to check this slot if we already know we want to wipe it or definitely keep it. */ if (set_contains(keep_slots, INT_TO_PTR(slot)) || set_contains(wipe_slots, INT_TO_PTR(slot))) continue; if (set_contains(listed_slots, INT_TO_PTR(slot))) /* This has a token, hence is not a password. */ continue; status = crypt_keyslot_status(cd, slot); if (!IN_SET(status, CRYPT_SLOT_ACTIVE, CRYPT_SLOT_ACTIVE_LAST)) /* Not actually assigned? */ continue; /* Finally, we found a password, add it to the list of slots to wipe */ if (set_put(wipe_slots, INT_TO_PTR(slot)) < 0) return log_oom(); } } return 0; } static int find_slot_tokens(struct crypt_device *cd, Set *wipe_slots, Set *keep_slots, Set *wipe_tokens) { int r; assert(cd); assert(wipe_slots); assert(keep_slots); assert(wipe_tokens); /* Find all tokens matching the slots we want to wipe, so that we can wipe them too. Also, for update * the slots sets according to the token data: add any other slots listed in the tokens we act on. */ for (int token = 0; token < sym_crypt_token_max(CRYPT_LUKS2); token++) { _cleanup_(json_variant_unrefp) JsonVariant *v = NULL; bool shall_wipe = false; JsonVariant *w, *z; r = cryptsetup_get_token_as_json(cd, token, NULL, &v); if (IN_SET(r, -ENOENT, -EINVAL)) continue; if (r < 0) { log_warning_errno(r, "Failed to read JSON token data off disk, ignoring: %m"); continue; } w = json_variant_by_key(v, "keyslots"); if (!w || !json_variant_is_array(w)) { log_warning("Token JSON data lacks keyslots field, ignoring."); continue; } /* Go through the slots associated with this token: if we shall keep any slot of them, the token shall stay too. */ JSON_VARIANT_ARRAY_FOREACH(z, w) { int slot; if (!json_variant_is_string(z)) { log_warning("Token JSON data's keyslot field is not an array of strings, ignoring."); continue; } r = safe_atoi(json_variant_string(z), &slot); if (r < 0) { log_warning_errno(r, "Token JSON data's keyslot filed is not an integer formatted as string, ignoring."); continue; } if (set_contains(keep_slots, INT_TO_PTR(slot))) { shall_wipe = false; break; /* If we shall keep this slot, then this is definite: we will keep its token too */ } /* If there's a slot associated with this token that we shall wipe, then remove the * token too. But we are careful here: let's continue iterating, maybe there's a slot * that we need to keep, in which case we can reverse the decision again. */ if (set_contains(wipe_slots, INT_TO_PTR(slot))) shall_wipe = true; } /* Go through the slots again, and this time add them to the list of slots to keep/remove */ JSON_VARIANT_ARRAY_FOREACH(z, w) { int slot; if (!json_variant_is_string(z)) continue; if (safe_atoi(json_variant_string(z), &slot) < 0) continue; if (set_put(shall_wipe ? wipe_slots : keep_slots, INT_TO_PTR(slot)) < 0) return log_oom(); } /* And of course, also remember the tokens to remove. */ if (shall_wipe) if (set_put(wipe_tokens, INT_TO_PTR(token)) < 0) return log_oom(); } return 0; } static bool slots_remain(struct crypt_device *cd, Set *wipe_slots, Set *keep_slots) { int slot_max; assert(cd); assert_se((slot_max = crypt_keyslot_max(CRYPT_LUKS2)) > 0); /* Checks if any slots remaining in the LUKS2 header if we remove all slots listed in 'wipe_slots' * (keeping those listed in 'keep_slots') */ for (int slot = 0; slot < slot_max; slot++) { crypt_keyslot_info status; status = crypt_keyslot_status(cd, slot); if (!IN_SET(status, CRYPT_SLOT_ACTIVE, CRYPT_SLOT_ACTIVE_LAST)) continue; /* The "keep" set wins if a slot is listed in both sets. This is important so that we can * safely add a new slot and remove all others of the same type, which in a naive * implementation might mean we remove what we just added — which we of course don't want. */ if (set_contains(keep_slots, INT_TO_PTR(slot)) || !set_contains(wipe_slots, INT_TO_PTR(slot))) return true; } return false; } int wipe_slots(struct crypt_device *cd, const int explicit_slots[], size_t n_explicit_slots, WipeScope by_scope, unsigned by_mask, int except_slot) { _cleanup_(set_freep) Set *wipe_slots = NULL, *wipe_tokens = NULL, *keep_slots = NULL; _cleanup_free_ int *ordered_slots = NULL, *ordered_tokens = NULL; size_t n_ordered_slots = 0, n_ordered_tokens = 0; int r, slot_max, ret; void *e; assert_se(cd); /* Shortcut if nothing to wipe. */ if (n_explicit_slots == 0 && by_mask == 0 && by_scope == WIPE_EXPLICIT) return 0; /* So this is a bit more complicated than I'd wish, but we want support three different axis for wiping slots: * * 1. Wiping by slot indexes * 2. Wiping slots of specified token types * 3. Wiping "all" entries, or entries with an empty password (i.e. "") * * (or any combination of the above) * * Plus: We always want to remove tokens matching the slots. * Plus: We always want to exclude the slots/tokens we just added. */ wipe_slots = set_new(NULL); keep_slots = set_new(NULL); wipe_tokens = set_new(NULL); if (!wipe_slots || !keep_slots || !wipe_tokens) return log_oom(); /* Let's maintain one set of slots for the slots we definitely want to keep */ if (except_slot >= 0) if (set_put(keep_slots, INT_TO_PTR(except_slot)) < 0) return log_oom(); assert_se((slot_max = crypt_keyslot_max(CRYPT_LUKS2)) > 0); /* Maintain another set of the slots we intend to wipe */ for (size_t i = 0; i < n_explicit_slots; i++) { if (explicit_slots[i] >= slot_max) return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Slot index %i out of range.", explicit_slots[i]); if (set_put(wipe_slots, INT_TO_PTR(explicit_slots[i])) < 0) return log_oom(); } /* Now, handle the "all" and "empty passphrase" cases. */ switch (by_scope) { case WIPE_EXPLICIT: break; /* Nothing to do here */ case WIPE_ALL: r = find_all_slots(cd, wipe_slots, keep_slots); if (r < 0) return r; break; case WIPE_EMPTY_PASSPHRASE: r = find_empty_passphrase_slots(cd, wipe_slots, keep_slots); if (r < 0) return r; break; default: assert_not_reached("Unexpected wipe scope"); } /* Then add all slots that match a token type */ r = find_slots_by_mask(cd, wipe_slots, keep_slots, by_mask); if (r < 0) return r; /* And determine tokens that we shall remove */ r = find_slot_tokens(cd, wipe_slots, keep_slots, wipe_tokens); if (r < 0) return r; /* Safety check: let's make sure that after we are done there's at least one slot remaining */ if (!slots_remain(cd, wipe_slots, keep_slots)) return log_error_errno(SYNTHETIC_ERRNO(EPERM), "Wipe operation would leave no valid slots around, can't allow that, sorry."); /* Generated ordered lists of the slots and the tokens to remove */ ordered_slots = new(int, set_size(wipe_slots)); if (!ordered_slots) return log_oom(); SET_FOREACH(e, wipe_slots) { int slot = PTR_TO_INT(e); if (set_contains(keep_slots, INT_TO_PTR(slot))) continue; ordered_slots[n_ordered_slots++] = slot; } typesafe_qsort(ordered_slots, n_ordered_slots, cmp_int); ordered_tokens = new(int, set_size(wipe_tokens)); if (!ordered_tokens) return log_oom(); SET_FOREACH(e, wipe_tokens) ordered_tokens[n_ordered_tokens++] = PTR_TO_INT(e); typesafe_qsort(ordered_tokens, n_ordered_tokens, cmp_int); if (n_ordered_slots == 0 && n_ordered_tokens == 0) { log_full(except_slot < 0 ? LOG_NOTICE : LOG_DEBUG, "No slots to remove selected."); return 0; } if (DEBUG_LOGGING) { for (size_t i = 0; i < n_ordered_slots; i++) log_debug("Going to wipe slot %i.", ordered_slots[i]); for (size_t i = 0; i < n_ordered_tokens; i++) log_debug("Going to wipe token %i.", ordered_tokens[i]); } /* Now, let's actually start wiping things. (We go from back to front, to make space at the end * first.) */ ret = 0; for (size_t i = n_ordered_slots; i > 0; i--) { r = crypt_keyslot_destroy(cd, ordered_slots[i - 1]); if (r < 0) { log_warning_errno(r, "Failed to wipe slot %i, continuing: %m", ordered_slots[i - 1]); if (ret == 0) ret = r; } else log_info("Wiped slot %i.", ordered_slots[i - 1]); } for (size_t i = n_ordered_tokens; i > 0; i--) { r = crypt_token_json_set(cd, ordered_tokens[i - 1], NULL); if (r < 0) { log_warning_errno(r, "Failed to wipe token %i, continuing: %m", ordered_tokens[i - 1]); if (ret == 0) ret = r; } } return ret; }