blob: 2255946643b3a9b842895eb79156b303a2ee9529 [file] [log] [blame]
/* 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;
}