openssl/crypto/cmp/cmp_util.c

/*
 * 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;
}

#define ERR_PRINT_BUF_SIZE 4096
/* 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_BUF_SIZE];
    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;
}

/*-
 * 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_sk_ASN1_UTF8STRING_push_str(STACK_OF(ASN1_UTF8STRING) *sk,
                                         const char *text)
{
    ASN1_UTF8STRING *utf8string;

    if (!ossl_assert(sk != NULL && text != NULL))
        return 0;
    if ((utf8string = ASN1_UTF8STRING_new()) == NULL)
        return 0;
    if (!ASN1_STRING_set(utf8string, text, -1))
        goto err;
    if (!sk_ASN1_UTF8STRING_push(sk, utf8string))
        goto err;
    return 1;

 err:
    ASN1_UTF8STRING_free(utf8string);
    return 0;
}

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;
}

/*
 * calculate a digest of the given certificate,
 * using the same hash algorithm as in the certificate signature.
 */
ASN1_OCTET_STRING *OSSL_CMP_X509_digest(const X509 *cert)
{
    unsigned int len;
    unsigned char hash[EVP_MAX_MD_SIZE];
    int md_NID;
    const EVP_MD *md = NULL;
    ASN1_OCTET_STRING *new = NULL;

    if (!ossl_assert(cert != NULL))
        return NULL;

    /*-
     * select hash algorithm, as stated in CMP RFC 4210 Appendix F.
     * Compilable ASN.1 defs:
     * the hash of the certificate, using the same hash algorithm
     * as is used to create and verify the certificate signature
     */
    if (!OBJ_find_sigid_algs(X509_get_signature_nid(cert), &md_NID, NULL)
            || (md = EVP_get_digestbynid(md_NID)) == NULL) {
        CMPerr(0, CMP_R_UNSUPPORTED_ALGORITHM);
        return NULL;
    }
    if (!X509_digest(cert, md, hash, &len)
            || (new = ASN1_OCTET_STRING_new()) == NULL)
        return NULL;
    if (!(ASN1_OCTET_STRING_set(new, hash, len))) {
        ASN1_OCTET_STRING_free(new);
        return NULL;
    }
    return new;
}