[Cryptech-Commits] [sw/libhal] 02/08: Checkpoint, not expected to work yet, includes a lot of notes.
git at cryptech.is
git at cryptech.is
Sun May 28 22:51:51 UTC 2017
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sra at hactrn.net pushed a commit to branch ks9
in repository sw/libhal.
commit 7c61f43d516dff9f1047d1c08a9bb778cb8edc68
Author: Rob Austein <sra at hactrn.net>
AuthorDate: Wed May 24 21:44:56 2017 -0400
Checkpoint, not expected to work yet, includes a lot of notes.
---
ks.c | 1131 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
ks.h | 241 ++++++++++++++
2 files changed, 1372 insertions(+)
diff --git a/ks.c b/ks.c
new file mode 100644
index 0000000..c107eb6
--- /dev/null
+++ b/ks.c
@@ -0,0 +1,1131 @@
+/*
+ * ks.c
+ * ----
+ * Keystore, generic parts anyway. This is internal within libhal.
+ *
+ * Copyright (c) 2015-2017, NORDUnet A/S All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ * - Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * - Neither the name of the NORDUnet nor the names of its contributors may
+ * be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+ * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+ * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
+ * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <stddef.h>
+#include <string.h>
+
+#include "hal.h"
+#include "hal_internal.h"
+#include "ks.h"
+
+/*
+ * Find a block in the index, return true (found) or false (not found).
+ * "where" indicates the name's position, or the position of the first free block.
+ *
+ * NB: This does NOT return a block number, it returns an index into
+ * ks->index[].
+ */
+
+static int ks_find(const hal_ks_t * const ks,
+ const hal_uuid_t * const uuid,
+ const int * const hint,
+ int *where)
+{
+ if (ks == NULL || ks->index == NULL || ks->names == NULL || uuid == NULL || where == NULL)
+ return 0;
+
+ if (hint != NULL && *hint >= 0 && *hint < ks->used &&
+ hal_uuid_cmp(uuid, &ks->names[ks->index[*hint]]) == 0) {
+ *where = *hint;
+ return 1;
+ }
+
+ int lo = -1;
+ int hi = ks->used;
+
+ for (;;) {
+ int m = (lo + hi) / 2;
+ if (hi == 0 || m == lo) {
+ *where = hi;
+ return 0;
+ }
+ const int cmp = hal_uuid_cmp(uuid, &ks->names[ks->index[m]]);
+ if (cmp < 0)
+ hi = m;
+ else if (cmp > 0)
+ lo = m;
+ else {
+ *where = m;
+ return 1;
+ }
+ }
+}
+
+/*
+ * Heapsort the index. We only need to do this on setup, for other
+ * operations we're just inserting or deleting a single entry in an
+ * already-ordered array, which is just a search problem. If we were
+ * really crunched for space, we could use an insertion sort here, but
+ * heapsort is easy and works well with data already in place.
+ */
+
+static inline void ks_heapsift(hal_ks_t *ks, int parent, const int end)
+{
+ if (ks == NULL || ks->index == NULL || ks->names == NULL || parent < 0 || end < parent)
+ return;
+ for (;;) {
+ const int left_child = parent * 2 + 1;
+ const int right_child = parent * 2 + 2;
+ int biggest = parent;
+ if (left_child <= end && hal_uuid_cmp(&ks->names[ks->index[biggest]],
+ &ks->names[ks->index[left_child]]) < 0)
+ biggest = left_child;
+ if (right_child <= end && hal_uuid_cmp(&ks->names[ks->index[biggest]],
+ &ks->names[ks->index[right_child]]) < 0)
+ biggest = right_child;
+ if (biggest == parent)
+ return;
+ const uint16_t tmp = ks->index[biggest];
+ ks->index[biggest] = ks->index[parent];
+ ks->index[parent] = tmp;
+ parent = biggest;
+ }
+}
+
+static inline void ks_heapsort(hal_ks_t *ks)
+{
+ if (ks == NULL || ks->index == NULL || ks->names == NULL)
+ return;
+ if (ks->used < 2)
+ return;
+ for (int i = (ks->used - 2) / 2; i >= 0; i--)
+ ks_heapsift(ks, i, ks->used - 1);
+ for (int i = ks->used - 1; i > 0; i--) {
+ const uint16_t tmp = ks->index[i];
+ ks->index[i] = ks->index[0];
+ ks->index[0] = tmp;
+ ks_heapsift(ks, 0, i - 1);
+ }
+}
+
+/*
+ * Perform a consistency check on the index.
+ */
+
+#define fsck(_ks) \
+ do { hal_error_t _err = hal_ks_index_fsck(_ks); if (_err != HAL_OK) return _err; } while (0)
+
+
+hal_error_t hal_ks_index_fsck(hal_ks_t *ks)
+{
+ if (ks == NULL || ks->index == NULL || ks->names == NULL ||
+ ks->size == 0 || ks->used > ks->size)
+ return HAL_ERROR_BAD_ARGUMENTS;
+
+ for (int i = 1; i < ks->used; i++)
+ if (hal_uuid_cmp(&ks->names[ks->index[i - 1]], &ks->names[ks->index[i]]) >= 0)
+ return HAL_ERROR_KS_INDEX_UUID_MISORDERED;
+
+ return HAL_OK;
+}
+
+/*
+ * Find a single block by name.
+ */
+
+hal_error_t hal_ks_index_find(hal_ks_t *ks,
+ const hal_uuid_t * const name,
+ unsigned *blockno,
+ int *hint)
+{
+ if (ks == NULL || ks->index == NULL || ks->names == NULL ||
+ ks->size == 0 || ks->used > ks->size || name == NULL)
+ return HAL_ERROR_BAD_ARGUMENTS;
+
+ int where;
+
+ fsck(ks);
+
+ int ok = ks_find(ks, name, hint, &where);
+
+ if (blockno != NULL)
+ *blockno = ks->index[where];
+
+ if (hint != NULL)
+ *hint = where;
+
+ return ok ? HAL_OK : HAL_ERROR_KEY_NOT_FOUND;
+}
+
+/*
+ * Add a single block to the index.
+ */
+
+hal_error_t hal_ks_index_add(hal_ks_t *ks,
+ const hal_uuid_t * const name,
+ unsigned *blockno,
+ int *hint)
+{
+ if (ks == NULL || ks->index == NULL || ks->names == NULL ||
+ ks->size == 0 || ks->used > ks->size || name == NULL)
+ return HAL_ERROR_BAD_ARGUMENTS;
+
+ if (ks->used == ks->size)
+ return HAL_ERROR_NO_KEY_INDEX_SLOTS;
+
+ int where;
+
+ fsck(ks);
+
+ if (ks_find(ks, name, hint, &where))
+ return HAL_ERROR_KEY_NAME_IN_USE;
+
+ /*
+ * Grab first block on free list, which makes room to slide the
+ * index up by one slot so we can insert the new block number.
+ */
+
+ const size_t len = (ks->used - where) * sizeof(*ks->index);
+ const uint16_t b = ks->index[ks->used++];
+ memmove(&ks->index[where + 1], &ks->index[where], len);
+ ks->index[where] = b;
+ ks->names[b] = *name;
+
+ if (blockno != NULL)
+ *blockno = b;
+
+ if (hint != NULL)
+ *hint = where;
+
+ fsck(ks);
+
+ return HAL_OK;
+}
+
+/*
+ * Delete a single block from the index.
+ */
+
+hal_error_t hal_ks_index_delete(hal_ks_t *ks,
+ const hal_uuid_t * const name,
+ unsigned *blockno,
+ int *hint)
+{
+ if (ks == NULL || ks->index == NULL || ks->names == NULL ||
+ ks->size == 0 || ks->used > ks->size || name == NULL)
+ return HAL_ERROR_BAD_ARGUMENTS;
+
+ int where;
+
+ fsck(ks);
+
+ if (ks->used == 0 || !ks_find(ks, name, hint, &where))
+ return HAL_ERROR_KEY_NOT_FOUND;
+
+ /*
+ * Free the block and stuff it at the end of the free list.
+ */
+
+ const size_t len = (ks->size - where - 1) * sizeof(*ks->index);
+ const uint16_t b = ks->index[where];
+ memmove(&ks->index[where], &ks->index[where + 1], len);
+ ks->index[ks->size - 1] = b;
+ ks->used--;
+ memset(&ks->names[b], 0, sizeof(ks->names[b]));
+
+ if (blockno != NULL)
+ *blockno = b;
+
+ if (hint != NULL)
+ *hint = where;
+
+ fsck(ks);
+
+ return HAL_OK;
+}
+
+/*
+ * Replace a single block in the index.
+ */
+
+hal_error_t hal_ks_index_replace(hal_ks_t *ks,
+ const hal_uuid_t * const name,
+ unsigned *blockno,
+ int *hint)
+{
+ if (ks == NULL || ks->index == NULL || ks->names == NULL ||
+ ks->size == 0 || ks->used > ks->size || name == NULL)
+ return HAL_ERROR_BAD_ARGUMENTS;
+
+ if (ks->used == ks->size)
+ return HAL_ERROR_NO_KEY_INDEX_SLOTS;
+
+ int where;
+
+ fsck(ks);
+
+ if (ks->used == 0 || !ks_find(ks, name, hint, &where))
+ return HAL_ERROR_KEY_NOT_FOUND;
+
+ /*
+ * Grab first block from free list, slide free list down, put old
+ * block at end of free list and replace old block with new block.
+ */
+
+ const size_t len = (ks->size - ks->used - 1) * sizeof(*ks->index);
+ const uint16_t b1 = ks->index[where];
+ const uint16_t b2 = ks->index[ks->used];
+ memmove(&ks->index[ks->used], &ks->index[ks->used + 1], len);
+ ks->index[ks->size - 1] = b1;
+ ks->index[where] = b2;
+ ks->names[b2] = *name;
+ memset(&ks->names[b1], 0, sizeof(ks->names[b1]));
+
+ if (blockno != NULL)
+ *blockno = b2;
+
+ if (hint != NULL)
+ *hint = where;
+
+ fsck(ks);
+
+ return HAL_OK;
+}
+
+/*
+ * Pick unused or least-recently-used slot in our in-memory cache.
+ *
+ * Updating lru values is caller's problem: if caller is using a cache
+ * slot as a temporary buffer and there's no point in caching the
+ * result, leave the lru values alone and the right thing will happen.
+ */
+
+static inline ks_block_t *cache_pick_lru(hal_ks_t *ks)
+{
+ uint32_t best_delta = 0;
+ int best_index = 0;
+
+ for (int i = 0; i < ks->cache_size; i++) {
+
+ if (ks->cache[i].blockno == ~0)
+ return &ks->cache[i].block;
+
+ const unsigned delta = ks->cache_lru - ks->cache[i].lru;
+ if (delta > best_delta) {
+ best_delta = delta;
+ best_index = i;
+ }
+
+ }
+
+ ks->cache[best_index].blockno = ~0;
+ return &ks->cache[best_index].block;
+}
+
+/*
+ * Find a block in our in-memory cache; return block or NULL if not present.
+ */
+
+static inline ks_block_t *cache_find_block(const hal_ks_t * const ks, const unsigned blockno)
+{
+ for (int i = 0; i < ks->cache_size; i++)
+ if (ks->cache[i].blockno == blockno)
+ return &ks->cache[i].block;
+ return NULL;
+}
+
+/*
+ * Mark a block in our in-memory cache as being in current use.
+ */
+
+static inline void cache_mark_used(hal_ks_t *ks, const ks_block_t * const block, const unsigned blockno)
+{
+ for (int i = 0; i < ks->cache_size; i++) {
+ if (&ks->cache[i].block == block) {
+ ks->cache[i].blockno = blockno;
+ ks->cache[i].lru = ++ks->cache_lru;
+ return;
+ }
+ }
+}
+
+/*
+ * Release a block from the in-memory cache.
+ */
+
+static inline void cache_release(hal_ks_t *ks, const ks_block_t * const block)
+{
+ if (block != NULL)
+ cache_mark_used(block, ~0);
+}
+
+/*
+ * Generate CRC-32 for a block.
+ *
+ * This function needs to understand the structure of
+ * ks_block_header_t, so that it can skip over fields that
+ * shouldn't be included in the CRC.
+ */
+
+static hal_crc32_t calculate_block_crc(const ks_block_t * const block)
+{
+ hal_crc32_t crc = hal_crc32_init();
+
+ if (block != NULL) {
+
+ crc = hal_crc32_update(crc, &block->header.block_type,
+ sizeof(block->header.block_type));
+
+ crc = hal_crc32_update(crc,
+ block->bytes + sizeof(ks_block_header_t),
+ sizeof(*block) - sizeof(ks_block_header_t));
+ }
+
+ return hal_crc32_finalize(crc);
+}
+
+/*
+ * Read a block using the cache. Marking the block as used is left
+ * for the caller, so we can avoid blowing out the cache when we
+ * perform a ks_match() operation.
+ */
+
+static hal_error_t block_read_cached(hal_ks_t *ks, const unsigned blockno, ks_block_t **block)
+{
+ if (block == NULL)
+ return HAL_ERROR_IMPOSSIBLE;
+
+ if ((*block = cache_find_block(ks, blockno)) != NULL)
+ return HAL_OK;
+
+ if ((*block = cache_pick_lru(ks)) == NULL)
+ return HAL_ERROR_IMPOSSIBLE;
+
+ return block_read(ks, blockno, *block);
+}
+
+/*
+ * Update one block, including zombie jamboree.
+ */
+
+static hal_error_t block_update(hal_ks_t *ks,
+ const unsigned b1,
+ ks_block_t *block,
+ const hal_uuid_t * const uuid,
+ int *hint)
+{
+ if (block == NULL)
+ return HAL_ERROR_IMPOSSIBLE;
+
+ if (ks->used == ks->size)
+ return HAL_ERROR_NO_KEY_INDEX_SLOTS;
+
+ cache_release(block);
+
+ hal_error_t err;
+ unsigned b2;
+
+ if ((err = block_deprecate(ks, b1)) != HAL_OK ||
+ (err = hal_ks_index_replace(ks, uuid, &b2, hint)) != HAL_OK ||
+ (err = block_write(ks, b2, block)) != HAL_OK ||
+ (err = block_zero(ks, b1)) != HAL_OK)
+ return err;
+
+ cache_mark_used(ks, block, b2);
+
+ /*
+ * Erase the first block in the free list. In case of restart, this
+ * puts the block back at the head of the free list.
+ */
+
+ return block_erase_maybe(ks, ks->index[ks->used]);
+}
+
+/*
+ * Initialize keystore. This includes various tricky bits, some of
+ * which attempt to preserve the free list ordering across reboots, to
+ * improve our simplistic attempt at wear leveling, others attempt to
+ * recover from unclean shutdown.
+ */
+
+static inline void *gnaw(uint8_t **mem, size_t *len, const size_t size)
+{
+ if (mem == NULL || *mem == NULL || len == NULL || size > *len)
+ return NULL;
+ void *ret = *mem;
+ *mem += size;
+ *len -= size;
+ return ret;
+}
+
+#warning Call ks_alloc_common() and ks_init_common() while holding hal_ks_lock(); !
+
+hal_error_t ks_alloc_common(hal_ks_t *ks, const unsigned ks_blocks, const unsigned cache_blocks)
+{
+ /*
+ * We allocate a single big chunk of memory rather than three
+ * smaller chunks to make it atomic. We need all three, so this way
+ * either all succeed or all fail.
+ */
+
+ size_t len = (sizeof(*ks->index) * ks_blocks +
+ sizeof(*ks->names) * ks_blocks +
+ sizeof(*ks->cache) * cache_blocks);
+
+ uint8_t *mem = hal_allocate_static_memory(len);
+
+ if (mem == NULL)
+ return HAL_ERROR_ALLOCATION_FAILURE;
+
+ memset(ks, 0, sizeof(*ks));
+ memset(mem, 0, len);
+
+ ks->index = gnaw(&mem, &len, sizeof(*ks->index) * ks_blocks);
+ ks->names = gnaw(&mem, &len, sizeof(*ks->names) * ks_blocks);
+ ks->cache = gnaw(&mem, &len, sizeof(*ks->cache) * cache_blocks);
+
+ ks->size = ks_blocks;
+ ks->cache_size = cache_blocks;
+
+ return HAL_OK;
+}
+
+hal_error_t ks_init_common(hal_ks_t *ks, const hal_ks_driver_t * const driver)
+{
+ if (ks->index == NULL || ks->names == NULL || ks->cache == NULL)
+ return HAL_ERROR_IMPOSSIBLE;
+
+ ks->used = 0;
+
+ for (int i = 0; i < ks->cache_size; i++)
+ ks->cache[i].blockno = ~0;
+
+ /*
+ * Scan existing content of keystore to figure out what we've got.
+ * This gets a bit involved due to the need to recover from things
+ * like power failures at inconvenient times.
+ */
+
+ ks_block_type_t block_types[ks->size];
+ ks_block_status_t block_status[ks->size];
+ ks_block_t *block = cache_pick_lru(ks);
+ int first_erased = -1;
+ hal_error_t err;
+ uint16_t n = 0;
+
+ if (block == NULL)
+ return HAL_ERROR_IMPOSSIBLE;
+
+ for (int i = 0; i < ks->size; i++) {
+
+ /*
+ * Read one block. If the CRC is bad or the block type is
+ * unknown, it's old data we don't understand, something we were
+ * writing when we crashed, or bad flash; in any of these cases,
+ * we want the block to end up near the end of the free list.
+ */
+
+ err = block_read(ks, i, block);
+
+ if (err == HAL_ERROR_KEYSTORE_BAD_CRC || err == HAL_ERROR_KEYSTORE_BAD_BLOCK_TYPE)
+ block_types[i] = BLOCK_TYPE_UNKNOWN;
+
+ else if (err == HAL_OK)
+ block_types[i] = block_get_type(block);
+
+ else
+ return err;
+
+ switch (block_types[i]) {
+ case BLOCK_TYPE_KEY:
+ case BLOCK_TYPE_PIN:
+ block_status[i] = block_get_status(block);
+ break;
+ default:
+ block_status[i] = BLOCK_STATUS_UNKNOWN;
+ }
+
+ /*
+ * First erased block we see is head of the free list.
+ */
+
+ if (block_types[i] == BLOCK_TYPE_ERASED && first_erased < 0)
+ first_erased = i;
+
+ /*
+ * If it's a valid data block, include it in the index. We remove
+ * tombstones (if any) below, for now it's easiest to include them
+ * in the index, so we can look them up by name if we must.
+ */
+
+ const hal_uuid_t *uuid = NULL;
+
+ switch (block_types[i]) {
+ case BLOCK_TYPE_KEY: uuid = &block->key.name; break;
+ case BLOCK_TYPE_PIN: uuid = &pin_uuid; break;
+ default: /* Keep GCC happy */ break;
+ }
+
+ if (uuid != NULL) {
+ ks->names[i] = *uuid;
+ ks->index[n++] = i;
+ }
+ }
+
+ ks->used = n;
+
+ if (ks->used > ks->size)
+ return HAL_ERROR_IMPOSSIBLE;
+
+ /*
+ * At this point we've built the (unsorted) index from all the valid
+ * blocks. Now we need to insert free and unrecognized blocks into
+ * the free list in our preferred order. It's possible that there's
+ * a better way to do this than linear scan, but this is just
+ * integer comparisons in a fairly small data set, so it's probably
+ * not worth trying to optimize.
+ */
+
+ if (n < ks->size)
+ for (int i = 0; i < ks->size; i++)
+ if (block_types[i] == BLOCK_TYPE_ERASED)
+ ks->index[n++] = i;
+
+ if (n < ks->size)
+ for (int i = first_erased; i < ks->size; i++)
+ if (block_types[i] == BLOCK_TYPE_ZEROED)
+ ks->index[n++] = i;
+
+ if (n < ks->size)
+ for (int i = 0; i < first_erased; i++)
+ if (block_types[i] == BLOCK_TYPE_ZEROED)
+ ks->index[n++] = i;
+
+ if (n < ks->size)
+ for (int i = 0; i < ks->size; i++)
+ if (block_types[i] == BLOCK_TYPE_UNKNOWN)
+ ks->index[n++] = i;
+
+ if (ks->used > ks->size)
+ return HAL_ERROR_IMPOSSIBLE;
+
+ /*
+ * Sort the index, then deal with tombstones. Tombstones are blocks
+ * left behind when something bad (like a power failure) happened
+ * while we updating. There can be at most one tombstone and one
+ * live block for a given UUID. If we find no live block, we need
+ * to restore it from the tombstone, after which we need to zero the
+ * tombstone in either case. The sequence of operations while
+ * updating is designed so that, barring a bug or a hardware
+ * failure, we should never lose data.
+ */
+
+ ks_heapsort(ks);
+
+ for (unsigned b_tomb = 0; b_tomb < ks->size; b_tomb++) {
+
+ if (block_status[b_tomb] != BLOCK_STATUS_TOMBSTONE)
+ continue;
+
+ hal_uuid_t name = ks->names[b_tomb];
+
+ int where = -1;
+
+ if ((err = hal_ks_index_find(ks, &name, NULL, &where)) != HAL_OK)
+ return err;
+
+ if (b_tomb != ks->index[where]) {
+ if (ks->used > where + 1 && b_tomb == ks->index[where + 1])
+ where = where + 1;
+ else if (0 <= where - 1 && b_tomb == ks->index[where - 1])
+ where = where - 1;
+ else
+ return HAL_ERROR_IMPOSSIBLE;
+ }
+
+ const int matches_next = where + 1 < ks->used && !hal_uuid_cmp(&name, &ks->names[ks->index[where + 1]]);
+ const int matches_prev = where - 1 >= 0 && !hal_uuid_cmp(&name, &ks->names[ks->index[where - 1]]);
+
+ if ((matches_prev && matches_next) ||
+ (matches_prev && block_status[ks->index[b_tomb - 1]] != BLOCK_STATUS_LIVE) ||
+ (matches_next && block_status[ks->index[b_tomb + 1]] != BLOCK_STATUS_LIVE))
+ return HAL_ERROR_IMPOSSIBLE;
+
+ if (matches_prev || matches_next) {
+ memmove(&ks->index[where], &ks->index[where + 1], (ks->size - where - 1) * sizeof(*ks->index));
+ ks->index[ks->size - 1] = b_tomb;
+ }
+
+ else {
+ unsigned b_live;
+ if ((err = block_read(ks, b_tomb, block)) != HAL_OK)
+ return err;
+ block->header.block_status = BLOCK_STATUS_LIVE;
+ if ((err = hal_ks_index_replace(ks, &name, &b_live, &where)) != HAL_OK ||
+ (err = block_write(ks, b_live, block)) != HAL_OK)
+ return err;
+ block_status[b_live] = BLOCK_STATUS_LIVE;
+ }
+
+ if ((err = block_zero(ks, b_tomb)) != HAL_OK)
+ return err;
+ block_types[ b_tomb] = BLOCK_TYPE_ZEROED;
+ block_status[b_tomb] = BLOCK_STATUS_UNKNOWN;
+ }
+
+ /*
+ * Erase first block on free list if it's not already erased.
+ */
+
+ if (ks->used < ks->size &&
+ (err = block_erase_maybe(ks, ks->index[ks->used])) != HAL_OK)
+ return err;
+
+ /*
+ * And we're finally done.
+ */
+
+ ks->driver = driver;
+
+ return HAL_OK;
+}
+
+static inline int acceptable_key_type(const hal_key_type_t type)
+{
+ switch (type) {
+ case HAL_KEY_TYPE_RSA_PRIVATE:
+ case HAL_KEY_TYPE_EC_PRIVATE:
+ case HAL_KEY_TYPE_RSA_PUBLIC:
+ case HAL_KEY_TYPE_EC_PUBLIC:
+ return 1;
+ default:
+ return 0;
+ }
+}
+
+hal_error_t ks_store(hal_ks_t *ks,
+ hal_pkey_slot_t *slot,
+ const uint8_t * const der, const size_t der_len)
+{
+ if (ks == NULL || slot == NULL || der == NULL || der_len == 0 || !acceptable_key_type(slot->type))
+ return HAL_ERROR_BAD_ARGUMENTS;
+
+ hal_error_t err = HAL_OK;
+ ks_block_t *block;
+ flash_key_block_t *k;
+ uint8_t kek[KEK_LENGTH];
+ size_t kek_len;
+ unsigned b;
+
+ hal_ks_lock();
+
+ if ((block = cache_pick_lru(ks)) == NULL) {
+ err = HAL_ERROR_IMPOSSIBLE;
+ goto done;
+ }
+
+ k = &block->key;
+
+ if ((err = hal_ks_index_add(ks, &slot->name, &b, &slot->hint)) != HAL_OK)
+ goto done;
+
+ cache_mark_used(ks, block, b);
+
+ memset(block, 0xFF, sizeof(*block));
+
+ block->header.block_type = BLOCK_TYPE_KEY;
+ block->header.block_status = BLOCK_STATUS_LIVE;
+
+ k->name = slot->name;
+ k->type = slot->type;
+ k->curve = slot->curve;
+ k->flags = slot->flags;
+ k->der_len = SIZEOF_FLASH_KEY_BLOCK_DER;
+ k->attributes_len = 0;
+
+ if (ks->used < ks->size)
+ err = block_erase_maybe(ks, ks->index[ks->used]);
+
+ if (err == HAL_OK)
+ err = hal_mkm_get_kek(kek, &kek_len, sizeof(kek));
+
+ if (err == HAL_OK)
+ err = hal_aes_keywrap(NULL, kek, kek_len, der, der_len, k->der, &k->der_len);
+
+ memset(kek, 0, sizeof(kek));
+
+ if (err == HAL_OK)
+ err = block_write(ks, b, block);
+
+ if (err == HAL_OK)
+ goto done;
+
+ memset(block, 0, sizeof(*block));
+ cache_release(ks, block);
+ (void) hal_ks_index_delete(ks, &slot->name, NULL, &slot->hint);
+
+ done:
+ hal_ks_unlock();
+ return err;
+}
+
+static hal_error_t ks_fetch(hal_ks_t *ks,
+ hal_pkey_slot_t *slot,
+ uint8_t *der, size_t *der_len, const size_t der_max)
+{
+ if (ks == NULL || slot == NULL)
+ return HAL_ERROR_BAD_ARGUMENTS;
+
+ hal_error_t err = HAL_OK;
+ ks_block_t *block;
+ unsigned b;
+
+ hal_ks_lock();
+
+ if ((err = hal_ks_index_find(ks, &slot->name, &b, &slot->hint)) != HAL_OK ||
+ (err = block_read_cached(ks, b, &block)) != HAL_OK)
+ goto done;
+
+ if (block_get_type(block) != BLOCK_TYPE_KEY) {
+ err = HAL_ERROR_KEYSTORE_WRONG_BLOCK_TYPE; /* HAL_ERROR_KEY_NOT_FOUND */
+ goto done;
+ }
+
+ cache_mark_used(ks, block, b);
+
+ flash_key_block_t *k = &block->key;
+
+ slot->type = k->type;
+ slot->curve = k->curve;
+ slot->flags = k->flags;
+
+ if (der == NULL && der_len != NULL)
+ *der_len = k->der_len;
+
+ if (der != NULL) {
+
+ uint8_t kek[KEK_LENGTH];
+ size_t kek_len, der_len_;
+ hal_error_t err;
+
+ if (der_len == NULL)
+ der_len = &der_len_;
+
+ *der_len = der_max;
+
+ if ((err = hal_mkm_get_kek(kek, &kek_len, sizeof(kek))) == HAL_OK)
+ err = hal_aes_keyunwrap(NULL, kek, kek_len, k->der, k->der_len, der, der_len);
+
+ memset(kek, 0, sizeof(kek));
+ }
+
+ done:
+ hal_ks_unlock();
+ return err;
+}
+
+static hal_error_t ks_delete(hal_ks_t *ks,
+ hal_pkey_slot_t *slot)
+{
+ if (ks == NULL || slot == NULL)
+ return HAL_ERROR_BAD_ARGUMENTS;
+
+ hal_error_t err = HAL_OK;
+ unsigned b;
+
+ hal_ks_lock();
+
+ if ((err = hal_ks_index_delete(ks, &slot->name, &b, &slot->hint)) != HAL_OK)
+ goto done;
+
+ cache_release(ks, cache_find_block(ks, b));
+
+ if ((err = block_zero(ks, b)) != HAL_OK)
+ goto done;
+
+ err = block_erase_maybe(ks, ks->index[ks->used]);
+
+ done:
+ hal_ks_unlock();
+ return err;
+}
+
+static inline hal_error_t locate_attributes(ks_block_t *block,
+ uint8_t **bytes, size_t *bytes_len,
+ unsigned **attrs_len)
+{
+ if (block == NULL || bytes == NULL || bytes_len == NULL || attrs_len == NULL)
+ return HAL_ERROR_IMPOSSIBLE;
+
+
+ if (block_get_type(block) != BLOCK_TYPE_KEY)
+ return HAL_ERROR_KEYSTORE_WRONG_BLOCK_TYPE;
+ *attrs_len = &block->key.attributes_len;
+ *bytes = block->key.der + block->key.der_len;
+ *bytes_len = SIZEOF_FLASH_KEY_BLOCK_DER - block->key.der_len;
+
+ return HAL_OK;
+}
+
+static hal_error_t ks_match(hal_ks_t *ks,
+ const hal_client_handle_t client,
+ const hal_session_handle_t session,
+ const hal_key_type_t type,
+ const hal_curve_name_t curve,
+ const hal_key_flags_t mask,
+ const hal_key_flags_t flags,
+ const hal_pkey_attribute_t *attributes,
+ const unsigned attributes_len,
+ hal_uuid_t *result,
+ unsigned *result_len,
+ const unsigned result_max,
+ const hal_uuid_t * const previous_uuid)
+{
+ if (ks == NULL || (attributes == NULL && attributes_len > 0) ||
+ result == NULL || result_len == NULL || previous_uuid == NULL)
+ return HAL_ERROR_BAD_ARGUMENTS;
+
+ hal_error_t err = HAL_OK;
+ ks_block_t *block;
+ int i = -1;
+
+ hal_ks_lock();
+
+ *result_len = 0;
+
+ err = hal_ks_index_find(ks, previous_uuid, NULL, &i);
+
+ if (err == HAL_ERROR_KEY_NOT_FOUND)
+ i--;
+ else if (err != HAL_OK)
+ goto done;
+
+ while (*result_len < result_max && ++i < ks->used) {
+
+ unsigned b = ks->index[i];
+
+ if ((err = block_read_cached(ks, b, &block)) != HAL_OK)
+ goto done;
+
+ if ((type != HAL_KEY_TYPE_NONE && type != block->key.type) ||
+ (curve != HAL_CURVE_NONE && curve != block->key.curve) ||
+ ((flags ^ block->key.flags) & mask) != 0)
+ continue;
+
+ if (attributes_len > 0) {
+ uint8_t need_attr[attributes_len];
+ uint8_t *bytes = NULL;
+ size_t bytes_len = 0;
+ unsigned *attrs_len;
+ int possible = 1;
+
+ memset(need_attr, 1, sizeof(need_attr));
+
+ if ((err = locate_attributes(block, &bytes, &bytes_len, &attrs_len)) != HAL_OK)
+ goto done;
+
+ if (*attrs_len > 0) {
+ hal_pkey_attribute_t attrs[*attrs_len];
+
+ if ((err = hal_ks_attribute_scan(bytes, bytes_len, attrs, *attrs_len, NULL)) != HAL_OK)
+ goto done;
+
+ for (int j = 0; possible && j < attributes_len; j++) {
+
+ if (!need_attr[j])
+ continue;
+
+ for (hal_pkey_attribute_t *a = attrs; a < attrs + *attrs_len; a++) {
+ if (a->type != attributes[j].type)
+ continue;
+ need_attr[j] = 0;
+ possible = (a->length == attributes[j].length &&
+ !memcmp(a->value, attributes[j].value, a->length));
+ break;
+ }
+ }
+ }
+
+ if (!possible || memchr(need_attr, 1, sizeof(need_attr)) != NULL)
+ continue;
+ }
+
+ result[*result_len] = ks->names[b];
+ ++*result_len;
+ }
+
+ err = HAL_OK;
+
+ done:
+ hal_ks_unlock();
+ return err;
+}
+
+static hal_error_t ks_set_attributes(hal_ks_t *ks,
+ hal_pkey_slot_t *slot,
+ const hal_pkey_attribute_t *attributes,
+ const unsigned attributes_len)
+{
+ if (ks == NULL || slot == NULL || attributes == NULL || attributes_len == 0)
+ return HAL_ERROR_BAD_ARGUMENTS;
+
+ hal_error_t err = HAL_OK;
+ ks_block_t *block;
+ unsigned b;
+
+ hal_ks_lock();
+
+ {
+ if ((err = hal_ks_index_find(ks, &slot->name, &b, &slot->hint)) != HAL_OK ||
+ (err = block_read_cached(ks, b, &block)) != HAL_OK)
+ goto done;
+
+ cache_mark_used(ks, block, b);
+
+ uint8_t *bytes = NULL;
+ size_t bytes_len = 0;
+ unsigned *attrs_len;
+
+ if ((err = locate_attributes(block, &bytes, &bytes_len, &attrs_len)) != HAL_OK)
+ goto done;
+
+ hal_pkey_attribute_t attrs[*attrs_len + attributes_len];
+ size_t total;
+
+ if ((err = hal_ks_attribute_scan(bytes, bytes_len, attrs, *attrs_len, &total)) != HAL_OK)
+ goto done;
+
+ for (int i = 0; err == HAL_OK && i < attributes_len; i++)
+ if (attributes[i].length == HAL_PKEY_ATTRIBUTE_NIL)
+ err = hal_ks_attribute_delete(bytes, bytes_len, attrs, attrs_len, &total,
+ attributes[i].type);
+ else
+ err = hal_ks_attribute_insert(bytes, bytes_len, attrs, attrs_len, &total,
+ attributes[i].type,
+ attributes[i].value,
+ attributes[i].length);
+
+ if (err == HAL_OK)
+ err = block_update(ks, b, block, &slot->name, &slot->hint);
+ else
+ cache_release(ks, block);
+ }
+
+ done:
+ hal_ks_unlock();
+ return err;
+}
+
+static hal_error_t ks_get_attributes(hal_ks_t *ks,
+ hal_pkey_slot_t *slot,
+ hal_pkey_attribute_t *attributes,
+ const unsigned attributes_len,
+ uint8_t *attributes_buffer,
+ const size_t attributes_buffer_len)
+{
+ if (ks == NULL || slot == NULL || attributes == NULL || attributes_len == 0 ||
+ attributes_buffer == NULL)
+ return HAL_ERROR_BAD_ARGUMENTS;
+
+ for (int i = 0; i < attributes_len; i++) {
+ attributes[i].length = 0;
+ attributes[i].value = NULL;
+ }
+
+ uint8_t *abuf = attributes_buffer;
+ ks_block_t *block = NULL;
+ hal_error_t err = HAL_OK;
+ unsigned found = 0;
+ unsigned b;
+
+ hal_ks_lock();
+
+ {
+ if ((err = hal_ks_index_find(ks, &slot->name, &b, &slot->hint)) != HAL_OK ||
+ (err = block_read_cached(ks, b, &block)) != HAL_OK)
+ goto done;
+
+ cache_mark_used(ks, block, b);
+
+ uint8_t *bytes = NULL;
+ size_t bytes_len = 0;
+ unsigned *attrs_len;
+
+ if ((err = locate_attributes(block, &bytes, &bytes_len, &attrs_len)) != HAL_OK)
+ goto done;
+
+ if (*attrs_len == 0) {
+ err = HAL_ERROR_ATTRIBUTE_NOT_FOUND;
+ goto done;
+ }
+
+ hal_pkey_attribute_t attrs[*attrs_len];
+
+ if ((err = hal_ks_attribute_scan(bytes, bytes_len, attrs, *attrs_len, NULL)) != HAL_OK)
+ goto done;
+
+ for (int i = 0; i < attributes_len; i++) {
+
+ if (attributes[i].length > 0)
+ continue;
+
+ int j = 0;
+ while (j < *attrs_len && attrs[j].type != attributes[i].type)
+ j++;
+ if (j >= *attrs_len)
+ continue;
+ found++;
+
+ attributes[i].length = attrs[j].length;
+
+ if (attributes_buffer_len == 0)
+ continue;
+
+ if (attrs[j].length > attributes_buffer + attributes_buffer_len - abuf) {
+ err = HAL_ERROR_RESULT_TOO_LONG;
+ goto done;
+ }
+
+ memcpy(abuf, attrs[j].value, attrs[j].length);
+ attributes[i].value = abuf;
+ abuf += attrs[j].length;
+ }
+
+ };
+
+ if (found < attributes_len && attributes_buffer_len > 0)
+ err = HAL_ERROR_ATTRIBUTE_NOT_FOUND;
+ else
+ err = HAL_OK;
+
+ done:
+ hal_ks_unlock();
+ return err;
+}
+
+/*
+ * Local variables:
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/ks.h b/ks.h
new file mode 100644
index 0000000..ff6d382
--- /dev/null
+++ b/ks.h
@@ -0,0 +1,241 @@
+// Notes towards unified keystore code (drivers become just low-level
+// "disk" I/O and perhaps a bit of local init/shutdown).
+//
+// Most of the structure definitions in ks_flash.c and ks_volatile.c
+// become common and go in ks.h (or wherever, but probably be enough
+// stuff that separate .h file might be easier to read).
+//
+// We already have
+//
+// typedef struct hal_ks hal_ks_t;
+//
+// which we "subclass" to get ks_t (ks_volatile) and db_t (ks_flash).
+// We can move more common stuff there.
+//
+// flash_block_t (etc) becomes ks_block_t (etc) as these data
+// structures will be used by all keystores, not just flash.
+//
+// We might want to fold hal_ks_index_t into hal_ks_t as everything
+// will be using it. Then again, it's relatively harmless as it is, a
+// bit more verbose trading for a bit more isolation. Probably go for
+// less verbose, for readability.
+//
+// Each keystore will still have some weird private stuff, like the
+// RAM for the keys themselves in the volatile case and the PIN stuff
+// in the flash case.
+//
+// The ks_flash cache, however, probably wants to become common code.
+// Yes we could get a bit more efficient if we skipped caching in the
+// volatile case, but that's not our bottleneck and there are some
+// cases where the code relies on knowing that mucking with the cache
+// copy is harmless until we write the block to "disk", don't want to
+// mess with that, so keep the flash model for volatile. Cache size
+// will need to become another hal_ks_t field.
+//
+// Don't remember exactly where we're doing the "subclassing" casts,
+// should be easy enough to find...except that ks_flash is mostly
+// ignoring that argument and using the static db variable directly.
+// ks_volatile may be closer to write on this point, as it already had
+// ks_to_ksv(). But most of the code will be in a driver-agnostic
+// ks.c (or whatever) and will be calling functions that care through
+// the driver, maybe this doesn't matter very much.
+//
+// Tedious though it sounds, might be simplest just to check each
+// function in ks_*.c to see whether it moves to ks.[ch] or becomes
+// something called by the new lower-level driver API. Need a sketch
+// of the lower-level driver API, chicken and egg there but probably
+// is init(), shutdown(), block_read(), block_deprecate(),
+// block_zero(), block_erase(), block_erase_maybe(), block-write().
+// Possible that some of these don't really need to be driver, was
+// mostly basing this on which things in ks_flash touch flash
+// directly-ish via the keystore_*() functions.
+//
+// Would be nice if we can make the API regular enough (inline
+// functions?) that user need not really care which functions are
+// driver-specific and which are layered on top, but that may be
+// impractical (or silly).
+//
+// Hmm, hal_ks_open() and hal_ks_close() don't quite fit new model,
+// what was I thinking there? Not much, existing implementations just
+// use that to get back a (hal_ks_t*), so really just checking the
+// binding between driver and keystore object.
+//
+// I think this boils down to another instance of the confusion
+// between what in Python would be Keystore.__new__() and
+// Keystore.__init__(). This even sort of fits with the weird `alloc`
+// parameter in ks_init().
+//
+// Maybe we can trust C memory initialization enough to use a zeroed
+// static variable as test for whether a keystore has been
+// initialized, and just have the low-level (driver) methods check
+// that and fail if trying to use an uninitialized keystore?
+//
+// Pythonesque view might be the right way to handle ks_init(0 and
+// ks_shutdown() too: in most cases we have inline functions which
+// call the driver function, but for these methods the subclass needs
+// to extend the abstract method, which translates, in C, to the
+// generic method calling the driver method of the same name at the
+// right time. Not quite what Python does but close enough.
+
+
+#ifndef _KS_H_
+#define _KS_H_
+
+#include "hal.h"
+#include "hal_internal.h"
+
+/*
+ * Size of a keystore "block".
+ *
+ * This must be an integer multiple of the flash subsector size, among
+ * other reasons because that's the minimum erasable unit.
+ */
+
+#ifndef HAL_KS_BLOCK_SIZE
+#define HAL_KS_BLOCK_SIZE (KEYSTORE_SUBSECTOR_SIZE * 1)
+#endif
+
+/*
+ * Known block states.
+ *
+ * C does not guarantee any particular representation for enums, so
+ * including enums directly in the block header isn't safe. Instead,
+ * we use an access method which casts when reading from the header.
+ * Writing to the header isn't a problem, because C does guarantee
+ * that enum is compatible with *some* integer type, it just doesn't
+ * specify which one.
+ */
+
+typedef enum {
+ KS_BLOCK_TYPE_ERASED = 0xFF, /* Pristine erased block (candidate for reuse) */
+ KS_BLOCK_TYPE_ZEROED = 0x00, /* Zeroed block (recently used) */
+ KS_BLOCK_TYPE_KEY = 0x55, /* Block contains key material */
+ KS_BLOCK_TYPE_PIN = 0xAA, /* Block contains PINs */
+ KS_BLOCK_TYPE_UNKNOWN = -1, /* Internal code for "I have no clue what this is" */
+} ks_block_type_t;
+
+/*
+ * Block status.
+ */
+
+typedef enum {
+ KS_BLOCK_STATUS_LIVE = 0x66, /* This is a live block */
+ KS_BLOCK_STATUS_TOMBSTONE = 0x44, /* This is a tombstone left behind during an update */
+ KS_BLOCK_STATUS_UNKNOWN = -1, /* Internal code for "I have no clue what this is" */
+} ks_block_status_t;
+
+/*
+ * Common header for all keystore block types.
+ * A few of these fields are deliberately omitted from the CRC.
+ */
+
+typedef struct {
+ uint8_t block_type;
+ uint8_t block_status;
+ hal_crc32_t crc;
+} ks_block_header_t;
+
+/*
+ * Key block. Tail end of "der" field (after der_len) used for attributes.
+ */
+
+typedef struct {
+ ks_block_header_t header;
+ hal_uuid_t name;
+ hal_key_type_t type;
+ hal_curve_name_t curve;
+ hal_key_flags_t flags;
+ size_t der_len;
+ unsigned attributes_len;
+ uint8_t der[]; /* Must be last field -- C99 "flexible array member" */
+} ks_blockkey_block_t;
+
+#define SIZEOF_KS_BLOCKKEY_BLOCK_DER \
+ (HAL_KS_BLOCK_SIZE - offsetof(ks_blockkey_block_t, der))
+
+/*
+ * PIN block. Also includes space for backing up the KEK when
+ * HAL_MKM_FLASH_BACKUP_KLUDGE is enabled.
+ */
+
+typedef struct {
+ ks_block_header_t header;
+ hal_ks_pin_t wheel_pin;
+ hal_ks_pin_t so_pin;
+ hal_ks_pin_t user_pin;
+#if HAL_MKM_FLASH_BACKUP_KLUDGE
+ uint32_t kek_set;
+ uint8_t kek[KEK_LENGTH];
+#endif
+} ks_blockpin_block_t;
+
+#define FLASH_KEK_SET 0x33333333
+
+/*
+ * One keystore block.
+ */
+
+typedef union {
+ uint8_t bytes[HAL_KS_BLOCK_SIZE];
+ ks_block_header_t header;
+ ks_blockkey_block_t key;
+ ks_blockpin_block_t pin;
+} ks_block_t;
+
+/*
+ * In-memory cache.
+ */
+
+typedef struct {
+ unsigned blockno;
+ unsigned lru;
+ ks_block_t block;
+} ks_cache_block_t;
+
+/*
+ * Medium-specific driver and in-memory database.
+ *
+ * The top-level structure is a static variable; the arrays are
+ * allocated at runtime using hal_allocate_static_memory() because
+ * they can get kind of large.
+ *
+ * Driver-specific stuff is handled by a form of subclassing: the
+ * driver embeds the hal_ks_t structure at the head of whatever else
+ * it needs, and performs (controlled, type-safe) casts as needed.
+ */
+
+typedef struct hal_ks_driver hal_ks_driver_t;
+typedef struct hal_ks hal_ks_t;
+
+struct hal_ks {
+ const hal_ks_driver_t *driver;
+ unsigned size; /* Blocks in keystore */
+ unsigned used; /* How many blocks are in use */
+ uint16_t *index; /* Index/freelist array */
+ hal_uuid_t *names; /* Keyname array */
+ unsigned cache_lru; /* Cache LRU counter */
+ unsigned cache_size; /* Size (how many blocks) in cache */
+ ks_cache_block_t *cache; /* Cache */
+ int per_session; /* Whether objects have per-session semantics (PKCS #11, sigh) */
+};
+
+struct hal_ks_driver {
+ hal_error_t (*init) (hal_ks_t *, const int alloc);
+ hal_error_t (*shutdown) (hal_ks_t *);
+ hal_error_t (*read) (hal_ks_t *, const unsigned blockno, ks_block_t *);
+ hal_error_t (*write) (hal_ks_t *, const unsigned blockno, ks_block_t *)
+ hal_error_t (*deprecate) (hal_ks_t *, const unsigned blockno);
+ hal_error_t (*zero) (hal_ks_t *, const unsigned blockno);
+ hal_error_t (*erase) (hal_ks_t *, const unsigned blockno);
+ hal_error_t (*erase_maybe) (hal_ks_t *, const unsigned blockno);
+ hal_error_t (*get_owner) (hal_ks_t *, const unsigned blockno, hal_client_handle_t *, hal_session_handle_t *);
+ hal_error_t (*set_owner) (hal_ks_t *, const unsigned blockno, const hal_client_handle_t, const hal_session_handle_t);
+};
+
+#endif /* _KS_H_ */
+
+/*
+ * Local variables:
+ * indent-tabs-mode: nil
+ * End:
+ */
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