/* $OpenBSD: tls_conninfo.c,v 1.20 2018/02/10 04:48:44 jsing Exp $ */
/*
 * Copyright (c) 2015 Joel Sing <jsing@openbsd.org>
 * Copyright (c) 2015 Bob Beck <beck@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <stdio.h>

#include <openssl/x509.h>

#include <tls.h>
#include "tls_internal.h"

int ASN1_time_tm_clamp_notafter(struct tm *tm);

#ifdef __VMS
ASN1_time_tm_clamp_notafter(struct tm *tm)
{
#ifdef SMALL_TIME_T
   struct tm broken_os_epoch_tm;
   time_t broken_os_epoch_time = INT_MAX;

   if (gmtime_r(&broken_os_epoch_time, &broken_os_epoch_tm) == NULL)
      return 0;

   if (ASN1_time_tm_cmp(tm, &broken_os_epoch_tm) == 1)
      memcpy(tm, &broken_os_epoch_tm, sizeof(*tm));
#endif
   return 1;
}
#endif /* __VMS */

int
tls_hex_string(const unsigned char *in, size_t inlen, char **out,
    size_t *outlen)
{
   static const char hex[] = "0123456789abcdef";
   size_t i, len;
   char *p;

   if (outlen != NULL)
      *outlen = 0;

   if (inlen >= SIZE_MAX)
      return (-1);
   if ((*out = reallocarray(NULL, inlen + 1, 2)) == NULL)
      return (-1);

   p = *out;
   len = 0;
   for (i = 0; i < inlen; i++) {
      p[len++] = hex[(in[i] >> 4) & 0x0f];
      p[len++] = hex[in[i] & 0x0f];
   }
   p[len++] = 0;

   if (outlen != NULL)
      *outlen = len;

   return (0);
}

static int
tls_get_peer_cert_hash(struct tls *ctx, char **hash)
{
   *hash = NULL;
   if (ctx->ssl_peer_cert == NULL)
      return (0);

   if (tls_cert_hash(ctx->ssl_peer_cert, hash) == -1) {
      tls_set_errorx(ctx, "unable to compute peer certificate hash - out of memory");
      *hash = NULL;
      return -1;
   }
   return 0;
}

static int
tls_get_peer_cert_issuer(struct tls *ctx,  char **issuer)
{
   X509_NAME *name = NULL;

   *issuer = NULL;
   if (ctx->ssl_peer_cert == NULL)
      return (-1);
   if ((name = X509_get_issuer_name(ctx->ssl_peer_cert)) == NULL)
      return (-1);
   *issuer = X509_NAME_oneline(name, 0, 0);
   if (*issuer == NULL)
      return (-1);
   return (0);
}

static int
tls_get_peer_cert_subject(struct tls *ctx, char **subject)
{
   X509_NAME *name = NULL;

   *subject = NULL;
   if (ctx->ssl_peer_cert == NULL)
      return (-1);
   if ((name = X509_get_subject_name(ctx->ssl_peer_cert)) == NULL)
      return (-1);
   *subject = X509_NAME_oneline(name, 0, 0);
   if (*subject == NULL)
      return (-1);
   return (0);
}

static int
tls_get_peer_cert_times(struct tls *ctx, time_t *notbefore,
    time_t *notafter)
{
   struct tm before_tm, after_tm;
   ASN1_TIME *before, *after;

   if (ctx->ssl_peer_cert == NULL)
      return (-1);

   memset(&before_tm, 0, sizeof(before_tm));
   memset(&after_tm, 0, sizeof(after_tm));

   if ((before = X509_get_notBefore(ctx->ssl_peer_cert)) == NULL)
      goto err;
   if ((after = X509_get_notAfter(ctx->ssl_peer_cert)) == NULL)
      goto err;
   if (ASN1_time_parse(before->data, before->length, &before_tm, 0) == -1)
      goto err;
   if (ASN1_time_parse(after->data, after->length, &after_tm, 0) == -1)
      goto err;
   if (!ASN1_time_tm_clamp_notafter(&after_tm))
      goto err;
#ifndef __VMS
        if ((*notbefore = timegm(&before_tm)) == -1)
                goto err;
        if ((*notafter = timegm(&after_tm)) == -1)
                goto err;
#else
        if ((int)(*notbefore = timegm(&before_tm)) == -1)
                goto err;
        if ((int)(*notafter = timegm(&after_tm)) == -1)
                goto err;
#endif

   return (0);

 err:
   return (-1);
}

static int
tls_get_peer_cert_info(struct tls *ctx)
{
   if (ctx->ssl_peer_cert == NULL)
      return (0);

   if (tls_get_peer_cert_hash(ctx, &ctx->conninfo->hash) == -1)
      goto err;
   if (tls_get_peer_cert_subject(ctx, &ctx->conninfo->subject) == -1)
      goto err;
   if (tls_get_peer_cert_issuer(ctx, &ctx->conninfo->issuer) == -1)
      goto err;
   if (tls_get_peer_cert_times(ctx, &ctx->conninfo->notbefore,
       &ctx->conninfo->notafter) == -1)
      goto err;

   return (0);

 err:
   return (-1);
}

static int
tls_conninfo_alpn_proto(struct tls *ctx)
{
   const unsigned char *p;
   unsigned int len;

   free(ctx->conninfo->alpn);
   ctx->conninfo->alpn = NULL;

   SSL_get0_alpn_selected(ctx->ssl_conn, &p, &len);
   if (len > 0) {
      if ((ctx->conninfo->alpn = malloc(len + 1)) == NULL)
         return (-1);
      memcpy(ctx->conninfo->alpn, p, len);
      ctx->conninfo->alpn[len] = '\0';
   }

   return (0);
}

static int
tls_conninfo_cert_pem(struct tls *ctx)
{
   int i, rv = -1;
   BIO *membio = NULL;
   BUF_MEM *bptr = NULL;

   if (ctx->ssl_peer_cert == NULL)
      return 0;
   if ((membio = BIO_new(BIO_s_mem()))== NULL)
      goto err;

   /*
    * We have to write the peer cert out separately, because
    * the certificate chain may or may not contain it.
    */
   if (!PEM_write_bio_X509(membio, ctx->ssl_peer_cert))
      goto err;
   for (i = 0; i < sk_X509_num(ctx->ssl_peer_chain); i++) {
      X509 *chaincert = sk_X509_value(ctx->ssl_peer_chain, i);
      if (chaincert != ctx->ssl_peer_cert &&
          !PEM_write_bio_X509(membio, chaincert))
         goto err;
   }

   BIO_get_mem_ptr(membio, &bptr);
   free(ctx->conninfo->peer_cert);
   ctx->conninfo->peer_cert_len = 0;
   if ((ctx->conninfo->peer_cert = malloc(bptr->length)) == NULL)
      goto err;
   ctx->conninfo->peer_cert_len = bptr->length;
   memcpy(ctx->conninfo->peer_cert, bptr->data,
       ctx->conninfo->peer_cert_len);

   /* BIO_free() will kill BUF_MEM - because we have not set BIO_NOCLOSE */
   rv = 0;
 err:
   BIO_free(membio);
   return rv;
}

static int
tls_conninfo_session(struct tls *ctx)
{
   ctx->conninfo->session_resumed = SSL_session_reused(ctx->ssl_conn);

   return 0;
}

int
tls_conninfo_populate(struct tls *ctx)
{
   const char *tmp;

   tls_conninfo_free(ctx->conninfo);

   if ((ctx->conninfo = calloc(1, sizeof(struct tls_conninfo))) == NULL) {
      tls_set_errorx(ctx, "out of memory");
      goto err;
   }

   if (tls_conninfo_alpn_proto(ctx) == -1)
      goto err;

   if ((tmp = SSL_get_cipher(ctx->ssl_conn)) == NULL)
      goto err;
   if ((ctx->conninfo->cipher = strdup(tmp)) == NULL)
      goto err;

   if (ctx->servername != NULL) {
      if ((ctx->conninfo->servername =
          strdup(ctx->servername)) == NULL)
         goto err;
   }

   if ((tmp = SSL_get_version(ctx->ssl_conn)) == NULL)
      goto err;
   if ((ctx->conninfo->version = strdup(tmp)) == NULL)
      goto err;

   if (tls_get_peer_cert_info(ctx) == -1)
      goto err;

   if (tls_conninfo_cert_pem(ctx) == -1)
      goto err;

   if (tls_conninfo_session(ctx) == -1)
      goto err;

   return (0);

 err:
   tls_conninfo_free(ctx->conninfo);
   ctx->conninfo = NULL;

   return (-1);
}

void
tls_conninfo_free(struct tls_conninfo *conninfo)
{
   if (conninfo == NULL)
      return;

   free(conninfo->alpn);
   free(conninfo->cipher);
   free(conninfo->servername);
   free(conninfo->version);

   free(conninfo->hash);
   free(conninfo->issuer);
   free(conninfo->subject);

   free(conninfo->peer_cert);

   free(conninfo);
}

const char *
tls_conn_alpn_selected(struct tls *ctx)
{
   if (ctx->conninfo == NULL)
      return (NULL);
   return (ctx->conninfo->alpn);
}

const char *
tls_conn_cipher(struct tls *ctx)
{
   if (ctx->conninfo == NULL)
      return (NULL);
   return (ctx->conninfo->cipher);
}

const char *
tls_conn_servername(struct tls *ctx)
{
   if (ctx->conninfo == NULL)
      return (NULL);
   return (ctx->conninfo->servername);
}

int
tls_conn_session_resumed(struct tls *ctx)
{
   if (ctx->conninfo == NULL)
      return (0);
   return (ctx->conninfo->session_resumed);
}

const char *
tls_conn_version(struct tls *ctx)
{
   if (ctx->conninfo == NULL)
      return (NULL);
   return (ctx->conninfo->version);
}