redis: fix misaligned metadata access (UBSAN)

diff --git a/src/redis/internal.h b/src/redis/internal.h
index 9e9a205ef999c86e60da1ffc41f6e46203a3675c..215bbdfe1326b6f8c4463748693c9fd5532b96bd 100644 (file)
--- a/src/redis/internal.h
+++ b/src/redis/internal.h
@@ -521,10 +521,13 @@ static exception_t upd_txn_lock(upd_meta_k key, rdb_txn_t *txn)
                throw(KNOT_EINVAL, RDB_EMALF);
        }
 
+       uint16_t counter = knot_wire_read_u16((uint8_t *)meta + offsetof(upd_meta_storage_t, counter));
        for (txn->id = TXN_MIN; txn->id <= TXN_MAX; ++txn->id) {
-               if (meta->lock[txn->id] == 0) {
-                       meta->counter = MAX(meta->counter + 1, 1);
-                       meta->lock[txn->id] = meta->counter;
+               uint16_t lock = knot_wire_read_u16((uint8_t *)meta + offsetof(upd_meta_storage_t, lock[txn->id]));
+               if (lock == 0) {
+                       counter = MAX((uint16_t)(counter + 1), (uint16_t)1);
+                       knot_wire_write_u16((uint8_t *)meta + offsetof(upd_meta_storage_t, counter), counter);
+                       knot_wire_write_u16((uint8_t *)meta + offsetof(upd_meta_storage_t, lock[txn->id]), counter);
                        break;
                }
        }
@@ -583,7 +586,7 @@ static int get_id(RedisModuleCtx *ctx, const arg_dname_t *origin, const rdb_txn_
                return KNOT_EINVAL;
        }
 
-       uint16_t id = meta->lock[txn->id];
+       uint16_t id = knot_wire_read_u16((uint8_t *)meta + offsetof(upd_meta_storage_t, lock[txn->id]));
        if (id == 0) {
                RedisModule_CloseKey(meta_key);
                return KNOT_EEXIST;
@@ -744,7 +747,8 @@ static upd_meta_k upd_meta_get_when_open(RedisModuleCtx *ctx, const arg_dname_t
        }
        size_t len = 0;
        const upd_meta_storage_t *transaction = (const upd_meta_storage_t *)RedisModule_StringDMA(key, &len, REDISMODULE_WRITE);
-       if (transaction->lock[txn->id] == 0) {
+       uint16_t lock = knot_wire_read_u16((uint8_t *)transaction + offsetof(upd_meta_storage_t, lock[txn->id]));
+       if (lock == 0) {
                RedisModule_CloseKey(key);
                return NULL;
        }
@@ -1220,7 +1224,7 @@ static exception_t zone_purge(RedisModuleCtx *ctx, const arg_dname_t *origin, rd
                size_t len = 0;
                upd_meta_storage_t *meta = (upd_meta_storage_t *)RedisModule_StringDMA(meta_key, &len, REDISMODULE_WRITE);
                RedisModule_Assert(len == sizeof(*meta));
-               meta->depth = 0;
+               knot_wire_write_u16((uint8_t *)meta + offsetof(upd_meta_storage_t, depth), 0);
        }
        RedisModule_CloseKey(meta_key);
 
@@ -1703,7 +1707,7 @@ static void upd_meta_unlock(RedisModuleCtx *ctx, upd_meta_k key, uint8_t id)
        size_t len = 0;
        upd_meta_storage_t *meta = (upd_meta_storage_t *)RedisModule_StringDMA(key, &len, REDISMODULE_WRITE);
        RedisModule_Assert(len == sizeof(*meta));
-       meta->lock[id] = 0;
+       knot_wire_write_u16((uint8_t *)meta + offsetof(upd_meta_storage_t, lock[id]), 0);
 }
 
 static exception_t upd_abort(RedisModuleCtx *ctx, const arg_dname_t *origin, rdb_txn_t *txn)
@@ -1960,7 +1964,8 @@ static void upd_commit(RedisModuleCtx *ctx, const arg_dname_t *origin, rdb_txn_t
                RedisModule_ReplyWithError(ctx, RDB_EHISTORY);
                return;
        }
-       meta->depth -= counter;
+       uint16_t depth = knot_wire_read_u16((uint8_t *)meta + offsetof(upd_meta_storage_t, depth));
+       knot_wire_write_u16((uint8_t *)meta + offsetof(upd_meta_storage_t, depth), depth - counter);
 
        // Commit the update.
        index_k new_upd_key = get_commited_upd_index(ctx, origin, upd_txn, serial_new, REDISMODULE_READ | REDISMODULE_WRITE);
@@ -2010,7 +2015,7 @@ static void upd_commit(RedisModuleCtx *ctx, const arg_dname_t *origin, rdb_txn_t
 
                RedisModule_CloseKey(diff_key);
        }
-       ++meta->depth;
+       knot_wire_write_u16((uint8_t *)meta + offsetof(upd_meta_storage_t, depth), ++depth);
        RedisModule_DeleteKey(upd_key);
        RedisModule_CloseKey(upd_key);
 
@@ -2038,7 +2043,7 @@ static void upd_commit(RedisModuleCtx *ctx, const arg_dname_t *origin, rdb_txn_t
 
        e = upd_trim_history(ctx, origin, upd_txn, rdb_upd_history_len);
        if (e.ret == KNOT_EOK) {
-               meta->depth = MIN(meta->depth, rdb_upd_history_len);
+               knot_wire_write_u16((uint8_t *)meta + offsetof(upd_meta_storage_t, depth), MIN(depth, rdb_upd_history_len));
        }
 
        upd_meta_unlock(ctx, meta_key, upd_txn->id);