/*
 * Copyright (c) 2005 - 2007 Kungliga Tekniska Högskolan
 * (Royal Institute of Technology, Stockholm, Sweden).
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. 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.
 *
 * 3. Neither the name of the Institute 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 INSTITUTE 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 INSTITUTE 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 "hx_locl.h"

typedef enum { USE_PEM, USE_DER } outformat;

struct ks_file {
    hx509_certs certs;
    char *fn;
    outformat format;
};

/*
 *
 */

static int
parse_certificate(hx509_context context, const char *fn,
                  struct hx509_collector *c,
                  const hx509_pem_header *headers,
                  const void *data, size_t len,
                  const AlgorithmIdentifier *ai)
{
    hx509_cert cert;
    int ret;

    ret = hx509_cert_init_data(context, data, len, &cert);
    if (ret)
        return ret;

    ret = _hx509_collector_certs_add(context, c, cert);
    hx509_cert_free(cert);
    return ret;
}

static int
try_decrypt(hx509_context context,
            struct hx509_collector *collector,
            const AlgorithmIdentifier *alg,
            const EVP_CIPHER *c,
            const void *ivdata,
            const void *password,
            size_t passwordlen,
            const void *cipher,
            size_t len)
{
    heim_octet_string clear;
    size_t keylen;
    void *key;
    int ret;

    keylen = EVP_CIPHER_key_length(c);

    key = malloc(keylen);
    if (key == NULL) {
        hx509_clear_error_string(context);
        return ENOMEM;
    }

    ret = EVP_BytesToKey(c, EVP_md5(), ivdata,
                         password, passwordlen,
                         1, key, NULL);
    if (ret <= 0) {
        hx509_set_error_string(context, 0, HX509_CRYPTO_INTERNAL_ERROR,
                               "Failed to do string2key for private key");
        return HX509_CRYPTO_INTERNAL_ERROR;
    }

    clear.data = malloc(len);
    if (clear.data == NULL) {
        hx509_set_error_string(context, 0, ENOMEM,
                               "Out of memory to decrypt for private key");
        ret = ENOMEM;
        goto out;
    }
    clear.length = len;

    {
        EVP_CIPHER_CTX *ctx;

        ctx = EVP_CIPHER_CTX_new();
        if (ctx == NULL) {
                hx509_set_error_string(context, 0, ENOMEM,
                                       "Out of memory to decrypt for private key");
                ret = ENOMEM;
                goto out;
        }
        EVP_CipherInit_ex(ctx, c, NULL, key, ivdata, 0);
        EVP_Cipher(ctx, clear.data, cipher, len);
        EVP_CIPHER_CTX_free(ctx);
    }

    ret = _hx509_collector_private_key_add(context,
                                           collector,
                                           alg,
                                           NULL,
                                           &clear,
                                           NULL);

    memset(clear.data, 0, clear.length);
out:
    free(clear.data);
    memset(key, 0, keylen);
    free(key);
    return ret;
}

static int
parse_pkcs8_private_key(hx509_context context, const char *fn,
                        struct hx509_collector *c,
                        const hx509_pem_header *headers,
                        const void *data, size_t length,
                        const AlgorithmIdentifier *ai)
{
    PKCS8PrivateKeyInfo ki;
    heim_octet_string keydata;

    int ret;

    ret = decode_PKCS8PrivateKeyInfo(data, length, &ki, NULL);
    if (ret)
        return ret;

    keydata.data = rk_UNCONST(data);
    keydata.length = length;

    ret = _hx509_collector_private_key_add(context,
                                           c,
                                           &ki.privateKeyAlgorithm,
                                           NULL,
                                           &ki.privateKey,
                                           &keydata);
    free_PKCS8PrivateKeyInfo(&ki);
    return ret;
}

static int
parse_pem_private_key(hx509_context context, const char *fn,
                      struct hx509_collector *c,
                      const hx509_pem_header *headers,
                      const void *data, size_t len,
                      const AlgorithmIdentifier *ai)
{
    int ret = 0;
    const char *enc;

    enc = hx509_pem_find_header(headers, "Proc-Type");
    if (enc) {
        const char *dek;
        char *type, *iv;
        ssize_t ssize, size;
        void *ivdata;
        const EVP_CIPHER *cipher;
        const struct _hx509_password *pw;
        hx509_lock lock;
        int decrypted = 0;
        size_t i;

        lock = _hx509_collector_get_lock(c);
        if (lock == NULL) {
            hx509_set_error_string(context, 0, HX509_ALG_NOT_SUPP,
                                   "Failed to get password for "
                                   "password protected file %s", fn);
            return HX509_ALG_NOT_SUPP;
        }

        if (strcmp(enc, "4,ENCRYPTED") != 0) {
            hx509_set_error_string(context, 0, HX509_PARSING_KEY_FAILED,
                                   "Private key encrypted in unknown method %s "
                                   "in file",
                                   enc, fn);
            hx509_clear_error_string(context);
            return HX509_PARSING_KEY_FAILED;
        }

        dek = hx509_pem_find_header(headers, "DEK-Info");
        if (dek == NULL) {
            hx509_set_error_string(context, 0, HX509_PARSING_KEY_FAILED,
                                   "Encrypted private key missing DEK-Info");
            return HX509_PARSING_KEY_FAILED;
        }

        type = strdup(dek);
        if (type == NULL) {
            hx509_clear_error_string(context);
            return ENOMEM;
        }

        iv = strchr(type, ',');
        if (iv == NULL) {
            free(type);
            hx509_set_error_string(context, 0, HX509_PARSING_KEY_FAILED,
                                   "IV missing");
            return HX509_PARSING_KEY_FAILED;
        }

        *iv++ = '\0';

        size = strlen(iv);
        ivdata = malloc(size);
        if (ivdata == NULL) {
            hx509_clear_error_string(context);
            free(type);
            return ENOMEM;
        }

        cipher = EVP_get_cipherbyname(type);
        if (cipher == NULL) {
            free(ivdata);
            hx509_set_error_string(context, 0, HX509_ALG_NOT_SUPP,
                                   "Private key encrypted with "
                                   "unsupported cipher: %s",
                                   type);
            free(type);
            return HX509_ALG_NOT_SUPP;
        }

#define PKCS5_SALT_LEN 8

        ssize = hex_decode(iv, ivdata, size);
        free(type);
        type = NULL;
        iv = NULL;

        if (ssize < 0 || ssize < PKCS5_SALT_LEN || ssize < EVP_CIPHER_iv_length(cipher)) {
            free(ivdata);
            hx509_set_error_string(context, 0, HX509_PARSING_KEY_FAILED,
                                   "Salt have wrong length in "
                                   "private key file");
            return HX509_PARSING_KEY_FAILED;
        }

        pw = _hx509_lock_get_passwords(lock);
        if (pw != NULL) {
            const void *password;
            size_t passwordlen;

            for (i = 0; i < pw->len; i++) {
                password = pw->val[i];
                passwordlen = strlen(password);

                ret = try_decrypt(context, c, ai, cipher, ivdata,
                                  password, passwordlen, data, len);
                if (ret == 0) {
                    decrypted = 1;
                    break;
                }
            }
        }
        if (!decrypted) {
            hx509_prompt prompt;
            char password[128];

            memset(&prompt, 0, sizeof(prompt));

            prompt.prompt = "Password for keyfile: ";
            prompt.type = HX509_PROMPT_TYPE_PASSWORD;
            prompt.reply.data = password;
            prompt.reply.length = sizeof(password);

            ret = hx509_lock_prompt(lock, &prompt);
            if (ret == 0)
                ret = try_decrypt(context, c, ai, cipher, ivdata, password,
                                  strlen(password), data, len);
            /* XXX add password to lock password collection ? */
            memset(password, 0, sizeof(password));
        }
        free(ivdata);

    } else {
        heim_octet_string keydata;

        keydata.data = rk_UNCONST(data);
        keydata.length = len;

        ret = _hx509_collector_private_key_add(context, c, ai, NULL,
                                               &keydata, NULL);
    }

    return ret;
}


struct pem_formats {
    const char *name;
    int (*func)(hx509_context, const char *, struct hx509_collector *,
                const hx509_pem_header *, const void *, size_t,
                const AlgorithmIdentifier *);
    const AlgorithmIdentifier *(*ai)(void);
} formats[] = {
    { "CERTIFICATE", parse_certificate, NULL },
    { "PRIVATE KEY", parse_pkcs8_private_key, NULL },
    { "RSA PRIVATE KEY", parse_pem_private_key, hx509_signature_rsa },
    { "EC PRIVATE KEY", parse_pem_private_key, hx509_signature_ecPublicKey }
};


struct pem_ctx {
    int flags;
    struct hx509_collector *c;
};

static int
pem_func(hx509_context context, const char *type,
         const hx509_pem_header *header,
         const void *data, size_t len, void *ctx)
{
    struct pem_ctx *pem_ctx = (struct pem_ctx*)ctx;
    int ret = 0;
    size_t j;

    for (j = 0; j < sizeof(formats)/sizeof(formats[0]); j++) {
        const char *q = formats[j].name;
        if (strcasecmp(type, q) == 0) {
            const AlgorithmIdentifier *ai = NULL;
            if (formats[j].ai != NULL)
                ai = (*formats[j].ai)();

            ret = (*formats[j].func)(context, NULL, pem_ctx->c,
                                     header, data, len, ai);
            if (ret && (pem_ctx->flags & HX509_CERTS_UNPROTECT_ALL)) {
                hx509_set_error_string(context, HX509_ERROR_APPEND, ret,
                                       "Failed parseing PEM format %s", type);
                return ret;
            }
            break;
        }
    }
    if (j == sizeof(formats)/sizeof(formats[0])) {
        ret = HX509_UNSUPPORTED_OPERATION;
        hx509_set_error_string(context, 0, ret,
                               "Found no matching PEM format for %s", type);
        return ret;
    }
    return 0;
}

/*
 *
 */

static int
file_init_common(hx509_context context,
                 hx509_certs certs, void **data, int flags,
                 const char *residue, hx509_lock lock, outformat format)
{
    char *p, *pnext;
    struct ks_file *ksf = NULL;
    hx509_private_key *keys = NULL;
    int ret;
    struct pem_ctx pem_ctx;

    pem_ctx.flags = flags;
    pem_ctx.c = NULL;

    *data = NULL;

    if (lock == NULL)
        lock = _hx509_empty_lock;

    ksf = calloc(1, sizeof(*ksf));
    if (ksf == NULL) {
        hx509_clear_error_string(context);
        return ENOMEM;
    }
    ksf->format = format;

    ksf->fn = strdup(residue);
    if (ksf->fn == NULL) {
        hx509_clear_error_string(context);
        ret = ENOMEM;
        goto out;
    }

    /*
     * XXX this is broken, the function should parse the file before
     * overwriting it
     */

    if (flags & HX509_CERTS_CREATE) {
        ret = hx509_certs_init(context, "MEMORY:ks-file-create",
                               0, lock, &ksf->certs);
        if (ret)
            goto out;
        *data = ksf;
        return 0;
    }

    ret = _hx509_collector_alloc(context, lock, &pem_ctx.c);
    if (ret)
        goto out;

    for (p = ksf->fn; p != NULL; p = pnext) {
        FILE *f;

        pnext = strchr(p, ',');
        if (pnext)
            *pnext++ = '\0';


        if ((f = fopen(p, "r")) == NULL) {
            ret = ENOENT;
            hx509_set_error_string(context, 0, ret,
                                   "Failed to open PEM file \"%s\": %s",
                                   p, strerror(errno));
            goto out;
        }
        rk_cloexec_file(f);

        ret = hx509_pem_read(context, f, pem_func, &pem_ctx);
        fclose(f);
        if (ret != 0 && ret != HX509_PARSING_KEY_FAILED)
            goto out;
        else if (ret == HX509_PARSING_KEY_FAILED) {
            size_t length;
            void *ptr;
            size_t i;

            ret = rk_undumpdata(p, &ptr, &length);
            if (ret) {
                hx509_clear_error_string(context);
                goto out;
            }

            for (i = 0; i < sizeof(formats)/sizeof(formats[0]); i++) {
                const AlgorithmIdentifier *ai = NULL;
                if (formats[i].ai != NULL)
                    ai = (*formats[i].ai)();

                ret = (*formats[i].func)(context, p, pem_ctx.c, NULL, ptr, length, ai);
                if (ret == 0)
                    break;
            }
            rk_xfree(ptr);
            if (ret) {
                hx509_clear_error_string(context);
                goto out;
            }
        }
    }

    ret = _hx509_collector_collect_certs(context, pem_ctx.c, &ksf->certs);
    if (ret)
        goto out;

    ret = _hx509_collector_collect_private_keys(context, pem_ctx.c, &keys);
    if (ret == 0) {
        int i;

        for (i = 0; keys[i]; i++)
            _hx509_certs_keys_add(context, ksf->certs, keys[i]);
        _hx509_certs_keys_free(context, keys);
    }

out:
    if (ret == 0)
        *data = ksf;
    else {
        if (ksf->fn)
            free(ksf->fn);
        free(ksf);
    }
    if (pem_ctx.c)
        _hx509_collector_free(pem_ctx.c);

    return ret;
}

static int
file_init_pem(hx509_context context,
              hx509_certs certs, void **data, int flags,
              const char *residue, hx509_lock lock)
{
    return file_init_common(context, certs, data, flags, residue, lock, USE_PEM);
}

static int
file_init_der(hx509_context context,
              hx509_certs certs, void **data, int flags,
              const char *residue, hx509_lock lock)
{
    return file_init_common(context, certs, data, flags, residue, lock, USE_DER);
}

static int
file_free(hx509_certs certs, void *data)
{
    struct ks_file *ksf = data;
    hx509_certs_free(&ksf->certs);
    free(ksf->fn);
    free(ksf);
    return 0;
}

struct store_ctx {
    FILE *f;
    outformat format;
};

static int
store_func(hx509_context context, void *ctx, hx509_cert c)
{
    struct store_ctx *sc = ctx;
    heim_octet_string data;
    int ret = 0;

    ret = hx509_cert_binary(context, c, &data);
    if (ret)
        return ret;

    switch (sc->format) {
    case USE_DER:
        fwrite(data.data, data.length, 1, sc->f);
        free(data.data);
        break;
    case USE_PEM:
        hx509_pem_write(context, "CERTIFICATE", NULL, sc->f,
                        data.data, data.length);
        free(data.data);
        if (_hx509_cert_private_key_exportable(c)) {
            hx509_private_key key = _hx509_cert_private_key(c);
            ret = _hx509_private_key_export(context, key,
                                            HX509_KEY_FORMAT_DER, &data);
            if (ret)
                break;
            ret = hx509_pem_write(context, _hx509_private_pem_name(key), NULL,
                                  sc->f, data.data, data.length);
            free(data.data);
        }
        break;
    }

    return ret;
}

static int
file_store(hx509_context context,
           hx509_certs certs, void *data, int flags, hx509_lock lock)
{
    struct ks_file *ksf = data;
    struct store_ctx sc;
    int ret;

    sc.f = fopen(ksf->fn, "w");
    if (sc.f == NULL) {
        hx509_set_error_string(context, 0, ENOENT,
                               "Failed to open file %s for writing");
        return ENOENT;
    }
    rk_cloexec_file(sc.f);
    sc.format = ksf->format;

    ret = hx509_certs_iter_f(context, ksf->certs, store_func, &sc);
    fclose(sc.f);
    return ret;
}

static int
file_add(hx509_context context, hx509_certs certs, void *data, hx509_cert c)
{
    struct ks_file *ksf = data;
    return hx509_certs_add(context, ksf->certs, c);
}

static int
file_iter_start(hx509_context context,
                hx509_certs certs, void *data, void **cursor)
{
    struct ks_file *ksf = data;
    return hx509_certs_start_seq(context, ksf->certs, cursor);
}

static int
file_iter(hx509_context context,
          hx509_certs certs, void *data, void *iter, hx509_cert *cert)
{
    struct ks_file *ksf = data;
    return hx509_certs_next_cert(context, ksf->certs, iter, cert);
}

static int
file_iter_end(hx509_context context,
              hx509_certs certs,
              void *data,
              void *cursor)
{
    struct ks_file *ksf = data;
    return hx509_certs_end_seq(context, ksf->certs, cursor);
}

static int
file_getkeys(hx509_context context,
             hx509_certs certs,
             void *data,
             hx509_private_key **keys)
{
    struct ks_file *ksf = data;
    return _hx509_certs_keys_get(context, ksf->certs, keys);
}

static int
file_addkey(hx509_context context,
             hx509_certs certs,
             void *data,
             hx509_private_key key)
{
    struct ks_file *ksf = data;
    return _hx509_certs_keys_add(context, ksf->certs, key);
}

static struct hx509_keyset_ops keyset_file = {
    "FILE",
    0,
    file_init_pem,
    file_store,
    file_free,
    file_add,
    NULL,
    file_iter_start,
    file_iter,
    file_iter_end,
    NULL,
    file_getkeys,
    file_addkey
};

static struct hx509_keyset_ops keyset_pemfile = {
    "PEM-FILE",
    0,
    file_init_pem,
    file_store,
    file_free,
    file_add,
    NULL,
    file_iter_start,
    file_iter,
    file_iter_end,
    NULL,
    file_getkeys,
    file_addkey
};

static struct hx509_keyset_ops keyset_derfile = {
    "DER-FILE",
    0,
    file_init_der,
    file_store,
    file_free,
    file_add,
    NULL,
    file_iter_start,
    file_iter,
    file_iter_end,
    NULL,
    file_getkeys,
    file_addkey
};


void
_hx509_ks_file_register(hx509_context context)
{
    _hx509_ks_register(context, &keyset_file);
    _hx509_ks_register(context, &keyset_pemfile);
    _hx509_ks_register(context, &keyset_derfile);
}