Adding upstream version 255.4.upstream/255.4

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 445 insertions, 0 deletions

diff --git a/src/cryptenroll/cryptenroll-wipe.c b/src/cryptenroll/cryptenroll-wipe.c
new file mode 100644
index 0000000..314ebd3
--- /dev/null
+++ b/src/cryptenroll/cryptenroll-wipe.c
@@ -0,0 +1,445 @@
+/* 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_free_ 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_free_ 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();
+        }
+
+        /* 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;
+}