/*
 * Copyright 2007-2019 The OpenSSL Project Authors. All Rights Reserved.
 * Copyright Nokia 2007-2019
 * Copyright Siemens AG 2015-2019
 *
 * Licensed under the Apache License 2.0 (the "License").  You may not use
 * this file except in compliance with the License.  You can obtain a copy
 * in the file LICENSE in the source distribution or at
 * https://www.openssl.org/source/license.html
 */

#include <string.h>
#include <openssl/cmp_util.h>
#include "cmp_local.h" /* just for decls of internal functions defined here */
#include <openssl/cmperr.h>
#include <openssl/err.h> /* should be implied by cmperr.h */
#include <openssl/x509v3.h>

/*
 * use trace API for CMP-specific logging, prefixed by "CMP " and severity
 */

int OSSL_CMP_log_open(void) /* is designed to be idempotent */
{
#ifndef OPENSSL_NO_STDIO
    BIO *bio = BIO_new_fp(stdout, BIO_NOCLOSE);

    if (bio != NULL && OSSL_trace_set_channel(OSSL_TRACE_CATEGORY_CMP, bio))
        return 1;
    BIO_free(bio);
#endif
    CMPerr(0, CMP_R_NO_STDIO);
    return 0;
}

void OSSL_CMP_log_close(void) /* is designed to be idempotent */
{
    (void)OSSL_trace_set_channel(OSSL_TRACE_CATEGORY_CMP, NULL);
}

/* return >= 0 if level contains logging level, possibly preceded by "CMP " */
#define max_level_len 5 /* = max length of the below strings, e.g., "EMERG" */
static OSSL_CMP_severity parse_level(const char *level)
{
    const char *end_level = strchr(level, ':');
    int len;
    char level_copy[max_level_len + 1];

    if (end_level == NULL)
        return -1;

    if (strncmp(level, OSSL_CMP_LOG_PREFIX,
                strlen(OSSL_CMP_LOG_PREFIX)) == 0)
        level += strlen(OSSL_CMP_LOG_PREFIX);
    len = end_level - level;
    if (len > max_level_len)
        return -1;
    OPENSSL_strlcpy(level_copy, level, len + 1);
    return
        strcmp(level_copy, "EMERG") == 0 ? OSSL_CMP_LOG_EMERG :
        strcmp(level_copy, "ALERT") == 0 ? OSSL_CMP_LOG_ALERT :
        strcmp(level_copy, "CRIT") == 0 ? OSSL_CMP_LOG_CRIT :
        strcmp(level_copy, "ERROR") == 0 ? OSSL_CMP_LOG_ERR :
        strcmp(level_copy, "WARN") == 0 ? OSSL_CMP_LOG_WARNING :
        strcmp(level_copy, "NOTE") == 0 ? OSSL_CMP_LOG_NOTICE :
        strcmp(level_copy, "INFO") == 0 ? OSSL_CMP_LOG_INFO :
        strcmp(level_copy, "DEBUG") == 0 ? OSSL_CMP_LOG_DEBUG :
        -1;
}

const char *ossl_cmp_log_parse_metadata(const char *buf,
                                        OSSL_CMP_severity *level,
                                        char **func, char **file, int *line)
{
    const char *p_func = buf;
    const char *p_file = buf == NULL ? NULL : strchr(buf, ':');
    const char *p_level = buf;
    const char *msg = buf;

    *level = -1;
    *func = NULL;
    *file = NULL;
    *line = 0;

    if (p_file != NULL) {
        const char *p_line = strchr(++p_file, ':');

        if ((*level = parse_level(buf)) < 0 && p_line != NULL) {
            /* check if buf contains location info and logging level */
            char *p_level_tmp = (char *)p_level;
            const long line_number = strtol(++p_line, &p_level_tmp, 10);

            p_level = p_level_tmp;
            if (p_level > p_line && *(p_level++) == ':') {
                if ((*level = parse_level(p_level)) >= 0) {
                    *func = OPENSSL_strndup(p_func, p_file - 1 - p_func);
                    *file = OPENSSL_strndup(p_file, p_line - 1 - p_file);
                    /* no real problem if OPENSSL_strndup() returns NULL */
                    *line = (int)line_number;
                    msg = strchr(p_level, ':') + 1;
                    if (*msg == ' ')
                        msg++;
                }
            }
        }
    }
    return msg;
}

#define UNKNOWN_FUNC "(unknown function)" /* the default for OPENSSL_FUNC */
/*
 * substitute fallback if component/function name is NULL or empty or contains
 * just pseudo-information "(unknown function)" due to -pedantic and macros.h
 */
static const char *improve_location_name(const char *func, const char *fallback)
{
    if (!ossl_assert(fallback != NULL))
        return NULL;
    return func == NULL || *func == '\0' || strcmp(func, UNKNOWN_FUNC) == 0
        ? fallback : func;
}

int OSSL_CMP_print_to_bio(BIO* bio, const char *component, const char *file,
                          int line, OSSL_CMP_severity level, const char *msg)
{
    const char *level_string =
        level == OSSL_CMP_LOG_EMERG ? "EMERG" :
        level == OSSL_CMP_LOG_ALERT ? "ALERT" :
        level == OSSL_CMP_LOG_CRIT ? "CRIT" :
        level == OSSL_CMP_LOG_ERR ? "error" :
        level == OSSL_CMP_LOG_WARNING ? "warning" :
        level == OSSL_CMP_LOG_NOTICE ? "NOTE" :
        level == OSSL_CMP_LOG_INFO ? "info" :
        level == OSSL_CMP_LOG_DEBUG ? "DEBUG" : "(unknown level)";

#ifndef NDEBUG
    if (BIO_printf(bio, "%s:%s:%d:", improve_location_name(component, "CMP"),
                   file, line) < 0)
        return 0;
#endif
    return BIO_printf(bio, OSSL_CMP_LOG_PREFIX"%s: %s\n",
                      level_string, msg) >= 0;
}

/*
 * auxiliary function for incrementally reporting texts via the error queue
 */
static void put_error(int lib, const char *func, int reason,
                      const char *file, int line)
{
    ERR_new();
    ERR_set_debug(file, line, func);
    ERR_set_error(lib, reason, NULL /* no data here, so fmt is NULL */);
}

#define ERR_print_errors_cb_LIMIT 4096 /* size of char buf[] variable there */
#define TYPICAL_MAX_OUTPUT_BEFORE_DATA 100
#define MAX_DATA_LEN (ERR_print_errors_cb_LIMIT-TYPICAL_MAX_OUTPUT_BEFORE_DATA)
void ossl_cmp_add_error_txt(const char *separator, const char *txt)
{
    const char *file = NULL;
    int line;
    const char *func = NULL;
    const char *data = NULL;
    int flags;
    unsigned long err = ERR_peek_last_error();

    if (separator == NULL)
        separator = "";
    if (err == 0)
        put_error(ERR_LIB_CMP, NULL, 0, "", 0);

    do {
        size_t available_len, data_len;
        const char *curr = txt, *next = txt;
        char *tmp;

        ERR_peek_last_error_all(&file, &line, &func, &data, &flags);
        if ((flags & ERR_TXT_STRING) == 0) {
            data = "";
            separator = "";
        }
        data_len = strlen(data);

        /* workaround for limit of ERR_print_errors_cb() */
        if (data_len >= MAX_DATA_LEN
                || strlen(separator) >= (size_t)(MAX_DATA_LEN - data_len))
            available_len = 0;
        else
            available_len = MAX_DATA_LEN - data_len - strlen(separator) - 1;
        /* MAX_DATA_LEN > available_len >= 0 */

        if (separator[0] == '\0') {
            const size_t len_next = strlen(next);

            if (len_next <= available_len) {
                next += len_next;
                curr = NULL; /* no need to split */
            }
            else {
                next += available_len;
                curr = next; /* will split at this point */
            }
        } else {
            while (*next != '\0' && (size_t)(next - txt) <= available_len) {
                curr = next;
                next = strstr(curr, separator);
                if (next != NULL)
                    next += strlen(separator);
                else
                    next = curr + strlen(curr);
            }
            if ((size_t)(next - txt) <= available_len)
                curr = NULL; /* the above loop implies *next == '\0' */
        }
        if (curr != NULL) {
            /* split error msg at curr since error data would get too long */
            if (curr != txt) {
                tmp = OPENSSL_strndup(txt, curr - txt);
                if (tmp == NULL)
                    return;
                ERR_add_error_data(2, separator, tmp);
                OPENSSL_free(tmp);
            }
            put_error(ERR_LIB_CMP, func, err, file, line);
            txt = curr;
        } else {
            ERR_add_error_data(2, separator, txt);
            txt = next; /* finished */
        }
    } while (*txt != '\0');
}

/* this is similar to ERR_print_errors_cb, but uses the CMP-specific cb type */
void OSSL_CMP_print_errors_cb(OSSL_cmp_log_cb_t log_fn)
{
    unsigned long err;
    char msg[ERR_print_errors_cb_LIMIT];
    const char *file = NULL, *func = NULL, *data = NULL;
    int line, flags;

    while ((err = ERR_get_error_all(&file, &line, &func, &data, &flags)) != 0) {
        const char *component =
            improve_location_name(func, ERR_lib_error_string(err));

        if (!(flags & ERR_TXT_STRING))
            data = NULL;
        BIO_snprintf(msg, sizeof(msg), "%s%s%s", ERR_reason_error_string(err),
                     data == NULL || *data == '\0' ? "" : " : ",
                     data == NULL ? "" : data);
        if (log_fn == NULL) {
#ifndef OPENSSL_NO_STDIO
            BIO *bio = BIO_new_fp(stderr, BIO_NOCLOSE);

            if (bio != NULL) {
                OSSL_CMP_print_to_bio(bio, component, file, line,
                                      OSSL_CMP_LOG_ERR, msg);
                BIO_free(bio);
            }
#else
            /* CMPerr(0, CMP_R_NO_STDIO) makes no sense during error printing */
#endif
        } else {
            if (log_fn(component, file, line, OSSL_CMP_LOG_ERR, msg) <= 0)
                break; /* abort outputting the error report */
        }
    }
}

/*
 * functions manipulating lists of certificates etc.
 * these functions could be generally useful.
 */

int ossl_cmp_sk_X509_add1_cert(STACK_OF(X509) *sk, X509 *cert,
                               int no_dup, int prepend)
{
    if (sk == NULL) {
        CMPerr(0, CMP_R_NULL_ARGUMENT);
        return 0;
    }
    if (no_dup) {
        /*
         * not using sk_X509_set_cmp_func() and sk_X509_find()
         * because this re-orders the certs on the stack
         */
        int i;

        for (i = 0; i < sk_X509_num(sk); i++) {
            if (X509_cmp(sk_X509_value(sk, i), cert) == 0)
                return 1;
        }
    }
    if (!X509_up_ref(cert))
        return 0;
    if (!sk_X509_insert(sk, cert, prepend ? 0 : -1)) {
        X509_free(cert);
        return 0;
    }
    return 1;
}

int ossl_cmp_sk_X509_add1_certs(STACK_OF(X509) *sk, STACK_OF(X509) *certs,
                                int no_self_issued, int no_dups, int prepend)
/* compiler would allow 'const' for the list of certs, yet they are up-ref'ed */
{
    int i;

    if (sk == NULL) {
        CMPerr(0, CMP_R_NULL_ARGUMENT);
        return 0;
    }
    for (i = 0; i < sk_X509_num(certs); i++) { /* certs may be NULL */
        X509 *cert = sk_X509_value(certs, i);

        if (!no_self_issued || X509_check_issued(cert, cert) != X509_V_OK) {
            if (!ossl_cmp_sk_X509_add1_cert(sk, cert, no_dups, prepend))
                return 0;
        }
    }
    return 1;
}

int ossl_cmp_X509_STORE_add1_certs(X509_STORE *store, STACK_OF(X509) *certs,
                                   int only_self_issued)
{
    int i;

    if (store == NULL) {
        CMPerr(0, CMP_R_NULL_ARGUMENT);
        return 0;
    }
    if (certs == NULL)
        return 1;
    for (i = 0; i < sk_X509_num(certs); i++) {
        X509 *cert = sk_X509_value(certs, i);

        if (!only_self_issued || X509_check_issued(cert, cert) == X509_V_OK)
            if (!X509_STORE_add_cert(store, cert)) /* ups cert ref counter */
                return 0;
    }
    return 1;
}

STACK_OF(X509) *ossl_cmp_X509_STORE_get1_certs(X509_STORE *store)
{
    int i;
    STACK_OF(X509) *sk;
    STACK_OF(X509_OBJECT) *objs;

    if (store == NULL) {
        CMPerr(0, CMP_R_NULL_ARGUMENT);
        return 0;
    }
    if ((sk = sk_X509_new_null()) == NULL)
        return NULL;
    objs = X509_STORE_get0_objects(store);
    for (i = 0; i < sk_X509_OBJECT_num(objs); i++) {
        X509 *cert = X509_OBJECT_get0_X509(sk_X509_OBJECT_value(objs, i));

        if (cert != NULL) {
            if (!sk_X509_push(sk, cert))
                goto err;
            if (!X509_up_ref(cert)) {
                (void)sk_X509_pop(sk);
                goto err;
            }
        }
    }
    return sk;

 err:
    sk_X509_pop_free(sk, X509_free);
    return NULL;
}

/*-
 * Builds up the certificate chain of certs as high up as possible using
 * the given list of certs containing all possible intermediate certificates and
 * optionally the (possible) trust anchor(s). See also ssl_add_cert_chain().
 *
 * Intended use of this function is to find all the certificates above the trust
 * anchor needed to verify an EE's own certificate.  Those are supposed to be
 * included in the ExtraCerts field of every first sent message of a transaction
 * when MSG_SIG_ALG is utilized.
 *
 * NOTE: This allocates a stack and increments the reference count of each cert,
 * so when not needed any more the stack and all its elements should be freed.
 * NOTE: in case there is more than one possibility for the chain,
 * OpenSSL seems to take the first one, check X509_verify_cert() for details.
 *
 * returns a pointer to a stack of (up_ref'ed) X509 certificates containing:
 *      - the EE certificate given in the function arguments (cert)
 *      - all intermediate certificates up the chain toward the trust anchor
 *        whereas the (self-signed) trust anchor is not included
 * returns NULL on error
 */
STACK_OF(X509) *ossl_cmp_build_cert_chain(STACK_OF(X509) *certs, X509 *cert)
{
    STACK_OF(X509) *chain = NULL, *result = NULL;
    X509_STORE *store = X509_STORE_new();
    X509_STORE_CTX *csc = NULL;

    if (certs == NULL || cert == NULL || store == NULL) {
        CMPerr(0, CMP_R_NULL_ARGUMENT);
        goto err;
    }

    csc = X509_STORE_CTX_new();
    if (csc == NULL)
        goto err;

    if (!ossl_cmp_X509_STORE_add1_certs(store, certs, 0)
            || !X509_STORE_CTX_init(csc, store, cert, NULL))
        goto err;

    (void)ERR_set_mark();
    /*
     * ignore return value as it would fail without trust anchor given in store
     */
    (void)X509_verify_cert(csc);

    /* don't leave any new errors in the queue */
    (void)ERR_pop_to_mark();

    chain = X509_STORE_CTX_get0_chain(csc);

    /* result list to store the up_ref'ed not self-issued certificates */
    if ((result = sk_X509_new_null()) == NULL)
        goto err;
    if (!ossl_cmp_sk_X509_add1_certs(result, chain, 1 /* no self-issued */,
                                     1 /* no duplicates */, 0)) {
        sk_X509_free(result);
        result = NULL;
    }

 err:
    X509_STORE_free(store);
    X509_STORE_CTX_free(csc);
    return result;
}

int ossl_cmp_asn1_octet_string_set1(ASN1_OCTET_STRING **tgt,
                                    const ASN1_OCTET_STRING *src)
{
    ASN1_OCTET_STRING *new;
    if (tgt == NULL) {
        CMPerr(0, CMP_R_NULL_ARGUMENT);
        return 0;
    }
    if (*tgt == src) /* self-assignment */
        return 1;

    if (src != NULL) {
        if ((new = ASN1_OCTET_STRING_dup(src)) == NULL)
            return 0;
    } else {
        new = NULL;
    }

    ASN1_OCTET_STRING_free(*tgt);
    *tgt = new;
    return 1;
}

int ossl_cmp_asn1_octet_string_set1_bytes(ASN1_OCTET_STRING **tgt,
                                          const unsigned char *bytes, int len)
{
    ASN1_OCTET_STRING *new = NULL;

    if (tgt == NULL) {
        CMPerr(0, CMP_R_NULL_ARGUMENT);
        return 0;
    }
    if (bytes != NULL) {
        if ((new = ASN1_OCTET_STRING_new()) == NULL
                || !(ASN1_OCTET_STRING_set(new, bytes, len))) {
            ASN1_OCTET_STRING_free(new);
            return 0;
        }
    }

    ASN1_OCTET_STRING_free(*tgt);
    *tgt = new;
    return 1;
}