LithosAnanke/src/starkernel/capsule/capsule_mint.c

/*
  StarForth — Steady-State Virtual Machine Runtime

  Copyright (c) 2023–2025 Robert A. James
  All rights reserved.

  Licensed under the StarForth License, Version 1.0
*/

#ifndef __STARKERNEL__
#error "capsule_mint.c is kernel-only"
#endif

#include "starkernel/capsule_mint.h"
#include "starkernel/homeblocks_sig.h"
#include "starkernel/user_identity_seed.h"
#include "starkernel/x509_ed25519.h"
#include "starkernel/ed25519.h"
#include "starkernel/rng.h"
#include "block_subsystem.h" /* compute_crc64() */
#include "blkio.h"
#include "log.h"
#include <string.h>
#include <stddef.h>

/* Fixed layout, devblock offsets from the drive's own start -- see
 * capsule_mint.h's own doc comment. */
#define MINT_CERT_DEVBLOCK        2u
#define MINT_CERT_DEVBLOCKS       1u
#define MINT_IDENTITY_SRC_OFFSET  3u
#define MINT_IDENTITY_SRC_DEVBLOCKS 2u /* 1 seed record + 1 personality source */
#define MINT_METADATA_DEVBLOCKS   5u  /* devblocks 0..4 reserved */

/* Real, working, minimal default personality -- FABRIC-2.md §F.6/§F.8's
 * "default personality content" question stays open (mint-time-fixed vs.
 * user-editable), but the identity this mints must actually do something
 * when RUNCAP births it, not just exist. Needs the "Block NNNN" header
 * capsule_exec_payload() requires (§F.18) -- discovered live, not
 * optional. 4999 is an unused block number (see capsules/ block-map).
 *
 * Loads common:messaging.4th + MSG-CD-INIT exactly like capsule_console.c's
 * own CONSOLE_IDENTITY_SRC -- every live VM except Hera owns a MSG-TICK
 * word for her per-idle-tick pump to VM-EXEC into (repl.c's Phase C loop).
 * A minted identity's RUNCAP-born VM is not exempt from that pump, so
 * omitting this left it spamming "UNKNOWN WORD: 'MSG-TICK'" every idle
 * tick forever from the moment WIREBIND made the VM live -- found live
 * minting a real second identity (FABRIC-2.md §F.26 follow-up). */
static const char MINT_DEFAULT_PERSONALITY[] =
    "Block 4999\n"
    "S\" common:messaging.4th\" EXEC\n"
    "MSG-CD-INIT\n"
    ": WELCOME ( -- ) .\" Minted identity -- default personality\" CR ;\n"
    "WELCOME\n";

/* Write exactly one devblock (4096 bytes) at devblock offset `devblock`,
 * as 4 consecutive 1KiB forth-block writes -- same convention
 * homeblocks_sig_check()'s own read loop already uses. */
static int write_devblock(struct blkio_dev *dev, uint32_t devblock,
                           const uint8_t *buf4096) {
    uint32_t base = devblock * 4u;
    for (uint32_t i = 0; i < 4u; i++) {
        if (blkio_write((blkio_dev_t *)dev, base + i,
                         buf4096 + (size_t)i * BLKIO_FORTH_BLOCK_SIZE) != BLKIO_OK) {
            return -1;
        }
    }
    return 0;
}

/* Read exactly one devblock (4096 bytes) at devblock offset `devblock`,
 * mirroring write_devblock() above -- used only by the post-write
 * verification pass (2026-09-06), to read back what was just written
 * rather than trusting blkio_write()'s BLK_OK return alone. */
static int read_devblock(struct blkio_dev *dev, uint32_t devblock,
                          uint8_t *buf4096) {
    uint32_t base = devblock * 4u;
    for (uint32_t i = 0; i < 4u; i++) {
        if (blkio_read((blkio_dev_t *)dev, base + i,
                        buf4096 + (size_t)i * BLKIO_FORTH_BLOCK_SIZE) != BLKIO_OK) {
            return -1;
        }
    }
    return 0;
}

/* Post-write verification (2026-09-06, direct instruction after a live
 * xHCI enumeration failure raised the question of whether MINT itself
 * could silently succeed without the data actually being readable back):
 * re-reads the identity record and re-runs homeblocks_sig_check() --
 * the exact same check a real attach later performs -- instead of trusting
 * every write_devblock() call's own BLK_OK return as proof the drive will
 * actually read back correctly. blkio_write() succeeding only means the
 * BOT command chain completed; it says nothing about whether those bytes
 * survive to be read back under real hardware/emulation conditions.
 * Logged entirely through log_message() -- LOG_ERROR with the specific
 * mismatch on failure, LOG_INFO confirming success -- not console_println,
 * so this doesn't add unconditional console/serial noise to every mint;
 * the MINT word's own caller (mama_forth_words.c) still reports the final
 * pass/fail result to the console either way via its existing console_
 * println() switch. Returns 0 if everything reads back correctly, -1
 * otherwise. */
static int verify_mint(struct blkio_dev *dev, uint32_t identity_src_offset,
                        const user_identity_seed_t *written_idrec) {
    homeblocks_sig_t verify_sig;
    homeblocks_sig_result_t sig_rc =
        homeblocks_sig_check(dev, HOMEBLOCKS_SIG_START_FBLOCK, &verify_sig);
    if (sig_rc != HOMEBLOCKS_SIG_OK) {
        log_message(LOG_ERROR,
                    "MINT verify: homeblocks_sig_check() did not read back OK (rc=%d)",
                    (int) sig_rc);
        return -1;
    }

    uint8_t readback_block[4096];
    if (read_devblock(dev, identity_src_offset, readback_block) != 0) {
        log_message(LOG_ERROR, "MINT verify: identity record read-back failed");
        return -1;
    }

    const user_identity_seed_t *readback_idrec =
        (const user_identity_seed_t *) readback_block;
    if (readback_idrec->magic != written_idrec->magic ||
        readback_idrec->version != written_idrec->version) {
        log_message(LOG_ERROR,
                    "MINT verify: identity record magic/version mismatch on read-back");
        return -1;
    }
    uint64_t want_crc = compute_crc64((const uint8_t *) readback_idrec,
                                       offsetof(user_identity_seed_t, crc));
    if (want_crc != readback_idrec->crc) {
        log_message(LOG_ERROR, "MINT verify: identity record CRC mismatch on read-back");
        return -1;
    }
    if (memcmp(readback_idrec, written_idrec, sizeof(*written_idrec)) != 0) {
        log_message(LOG_ERROR,
                    "MINT verify: identity record content differs from what was written");
        return -1;
    }

    log_message(LOG_INFO, "MINT verify: identity reads back correctly");
    return 0;
}

MintResult capsule_mint_identity(struct blkio_dev *dev, VM *issuer_vm,
                                  const char *full_name, const char *username,
                                  const char *email, const char *phone,
                                  uint8_t out_pubkey[32], uint8_t out_seed[32],
                                  int drive_known_blank) {
    if (!dev || !full_name || !username) return MINT_ERR_WRITE_FAIL;

    /* full_name/username required and must fit; email/phone may be NULL
     * (treated as empty/null) but must fit if given. */
    if (full_name[0] == '\0' || strlen(full_name) >= USER_IDENTITY_FULL_NAME_MAX)
        return MINT_ERR_INVALID_PROFILE;
    if (username[0] == '\0' || strlen(username) >= USER_IDENTITY_USERNAME_MAX)
        return MINT_ERR_INVALID_PROFILE;
    if (email && strlen(email) >= USER_IDENTITY_EMAIL_MAX)
        return MINT_ERR_INVALID_PROFILE;
    if (phone && strlen(phone) >= USER_IDENTITY_PHONE_MAX)
        return MINT_ERR_INVALID_PROFILE;

    /* Refuse to overwrite an already-recognized home-blocks drive --
     * mirrors WRITE(10)'s own refuse-on-non-blank-media posture (§F.8,
     * decided 2026-08-28: "reasonable by analogy" there, now decided).
     * Skipped when the caller already just confirmed HOMEBLOCKS_SIG_BLANK
     * itself (drive_known_blank) -- otherwise this repeats the exact same
     * full BOT read sequence a second time immediately after the first. */
    if (!drive_known_blank) {
        homeblocks_sig_t existing;
        if (homeblocks_sig_check(dev, HOMEBLOCKS_SIG_START_FBLOCK, &existing)
            == HOMEBLOCKS_SIG_OK) {
            return MINT_ERR_ALREADY_MINTED;
        }
    }

    /* issuer_vm==NULL is genesis mode (§F.21) -- no existing Zuse to
     * require a cert from. */
    if (issuer_vm && !issuer_vm->zuse_cert_installed) return MINT_ERR_NO_ZUSE_CERT;
    if (!rng_ready())                                  return MINT_ERR_NO_ENTROPY;

    /* Fresh identity keypair. */
    uint8_t seed[32], pubkey[32];
    if (rng_get_bytes(seed, sizeof(seed)) != 0) return MINT_ERR_NO_ENTROPY;
    ed25519_keygen(seed, pubkey);
    if (out_pubkey) memcpy(out_pubkey, pubkey, 32);
    if (out_seed)   memcpy(out_seed, seed, 32);

    /* Fresh drive_uuid -- an independent random draw, not derived from
     * the identity seed (§F.8 decision 3: "which physical drive," not
     * "whose identity"). */
    uint8_t drive_uuid[16];
    if (rng_get_bytes(drive_uuid, sizeof(drive_uuid)) != 0)
        return MINT_ERR_NO_ENTROPY;

    uint32_t cert_devblock  = 0;
    uint32_t cert_devblocks = 0;
    if (issuer_vm) {
        /* Cert: SubjectPublicKeyInfo = new pubkey, serialNumber =
         * drive_uuid, signed by Zuse's own on-device seed (§F.8
         * decision 4). Genesis mode (issuer_vm==NULL) skips this
         * entirely -- Zuse's own identity isn't verified against a
         * separate signer, she's recognized directly by pubkey match
         * against zuse_genesis_marker_t (§F.21). */
        uint8_t cert[512];
        size_t  cert_len = x509_build_user_cert(cert, sizeof(cert), pubkey,
                                                 drive_uuid, issuer_vm->zuse_cert_seed);
        if (cert_len == 0 || cert_len > 4096) return MINT_ERR_CERT_BUILD;

        uint8_t cert_block[4096];
        memset(cert_block, 0, sizeof(cert_block));
        memcpy(cert_block, cert, cert_len);
        if (write_devblock(dev, MINT_CERT_DEVBLOCK, cert_block) != 0)
            return MINT_ERR_WRITE_FAIL;

        cert_devblock  = MINT_CERT_DEVBLOCK;
        cert_devblocks = MINT_CERT_DEVBLOCKS;
    }

    /* user_identity_seed_t record. */
    user_identity_seed_t idrec;
    memset(&idrec, 0, sizeof(idrec));
    idrec.magic   = USER_IDENTITY_SEED_MAGIC;
    idrec.version = USER_IDENTITY_SEED_VERSION;
    memcpy(idrec.seed, seed, 32);
    memcpy(idrec.pubkey, pubkey, 32);
    memcpy(idrec.full_name, full_name, strlen(full_name));
    memcpy(idrec.username, username, strlen(username));
    if (email) memcpy(idrec.email, email, strlen(email));
    if (phone) memcpy(idrec.phone, phone, strlen(phone));
    idrec.crc = compute_crc64((const uint8_t *)&idrec, offsetof(user_identity_seed_t, crc));
    if (write_devblock(dev, MINT_IDENTITY_SRC_OFFSET, (const uint8_t *)&idrec) != 0)
        return MINT_ERR_WRITE_FAIL;

    /* Default personality source, in the devblock right after the seed
     * record -- RUNCAP reads exactly this layout. */
    uint8_t personality_block[4096];
    memset(personality_block, 0, sizeof(personality_block));
    memcpy(personality_block, MINT_DEFAULT_PERSONALITY, sizeof(MINT_DEFAULT_PERSONALITY) - 1);
    if (write_devblock(dev, MINT_IDENTITY_SRC_OFFSET + 1u, personality_block) != 0)
        return MINT_ERR_WRITE_FAIL;

    /* homeblocks_sig_t -- written last, so a crash/power-loss partway
     * through minting never leaves a drive that reads as a valid,
     * complete home-blocks drive with missing content behind it. */
    homeblocks_sig_t sig;
    memset(&sig, 0, sizeof(sig));
    sig.magic                    = HOMEBLOCKS_SIG_PACK(HOMEBLOCKS_SIG_VERSION_0);
    memcpy(sig.drive_uuid, drive_uuid, 16);
    sig.minted_time_ns            = 0; /* no monotonic-ns source exists
                                         * anywhere in this codebase yet,
                                         * §F.8's own open item */
    sig.metadata_devblocks        = MINT_METADATA_DEVBLOCKS;
    sig.cert_offset                = cert_devblock;
    sig.cert_devblocks             = cert_devblocks;
    sig.identity_src_offset        = MINT_IDENTITY_SRC_OFFSET;
    sig.identity_src_devblocks     = MINT_IDENTITY_SRC_DEVBLOCKS;
    sig.hdr_crc                    = homeblocks_sig_compute_crc(&sig);

    uint8_t sig_block[4096];
    memcpy(sig_block, &sig, sizeof(sig));
    if (write_devblock(dev, HOMEBLOCKS_SIG_START_FBLOCK / 4u, sig_block) != 0)
        return MINT_ERR_WRITE_FAIL;

    (void)blkio_flush((blkio_dev_t *)dev);

    if (verify_mint(dev, MINT_IDENTITY_SRC_OFFSET, &idrec) != 0) {
        return MINT_ERR_VERIFY_FAILED;
    }

    return MINT_OK;
}