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ssl_ciph.c

/* ssl/ssl_ciph.c */
/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young (eay@cryptsoft.com).
 * The implementation was written so as to conform with Netscapes SSL.
 * 
 * This library is free for commercial and non-commercial use as long as
 * the following conditions are aheared to.  The following conditions
 * apply to all code found in this distribution, be it the RC4, RSA,
 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
 * included with this distribution is covered by the same copyright terms
 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
 * 
 * Copyright remains Eric Young's, and as such any Copyright notices in
 * the code are not to be removed.
 * If this package is used in a product, Eric Young should be given attribution
 * as the author of the parts of the library used.
 * This can be in the form of a textual message at program startup or
 * in documentation (online or textual) provided with the package.
 * 
 * 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 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    "This product includes cryptographic software written by
 *     Eric Young (eay@cryptsoft.com)"
 *    The word 'cryptographic' can be left out if the rouines from the library
 *    being used are not cryptographic related :-).
 * 4. If you include any Windows specific code (or a derivative thereof) from 
 *    the apps directory (application code) you must include an acknowledgement:
 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
 * 
 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``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 AUTHOR 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.
 * 
 * The licence and distribution terms for any publically available version or
 * derivative of this code cannot be changed.  i.e. this code cannot simply be
 * copied and put under another distribution licence
 * [including the GNU Public Licence.]
 */

#include <stdio.h>
#include <openssl/objects.h>
#include <openssl/comp.h>
#include <openssl/fips.h>
#include "ssl_locl.h"

#define SSL_ENC_DES_IDX       0
#define SSL_ENC_3DES_IDX      1
#define SSL_ENC_RC4_IDX       2
#define SSL_ENC_RC2_IDX       3
#define SSL_ENC_IDEA_IDX      4
#define SSL_ENC_eFZA_IDX      5
#define SSL_ENC_NULL_IDX      6
#define SSL_ENC_AES128_IDX    7
#define SSL_ENC_AES256_IDX    8
#define SSL_ENC_NUM_IDX       9

static const EVP_CIPHER *ssl_cipher_methods[SSL_ENC_NUM_IDX]={
      NULL,NULL,NULL,NULL,NULL,NULL,
      };

static STACK_OF(SSL_COMP) *ssl_comp_methods=NULL;

#define SSL_MD_MD5_IDX  0
#define SSL_MD_SHA1_IDX 1
#define SSL_MD_NUM_IDX  2
static const EVP_MD *ssl_digest_methods[SSL_MD_NUM_IDX]={
      NULL,NULL,
      };

#define CIPHER_ADD      1
#define CIPHER_KILL     2
#define CIPHER_DEL      3
#define CIPHER_ORD      4
#define CIPHER_SPECIAL  5

typedef struct cipher_order_st
      {
      SSL_CIPHER *cipher;
      int active;
      int dead;
      struct cipher_order_st *next,*prev;
      } CIPHER_ORDER;

static const SSL_CIPHER cipher_aliases[]={
      /* Don't include eNULL unless specifically enabled. */
      {0,SSL_TXT_ALL, 0,SSL_ALL & ~SSL_eNULL, SSL_ALL ,0,0,0,SSL_ALL,SSL_ALL}, /* must be first */
        {0,SSL_TXT_CMPALL,0,SSL_eNULL,0,0,0,0,SSL_ENC_MASK,0},  /* COMPLEMENT OF ALL */
      {0,SSL_TXT_CMPDEF,0,SSL_ADH, 0,0,0,0,SSL_AUTH_MASK,0},
        {0,SSL_TXT_kKRB5,0,SSL_kKRB5,0,0,0,0,SSL_MKEY_MASK,0},  /* VRS Kerberos5 */
      {0,SSL_TXT_kRSA,0,SSL_kRSA,  0,0,0,0,SSL_MKEY_MASK,0},
      {0,SSL_TXT_kDHr,0,SSL_kDHr,  0,0,0,0,SSL_MKEY_MASK,0},
      {0,SSL_TXT_kDHd,0,SSL_kDHd,  0,0,0,0,SSL_MKEY_MASK,0},
      {0,SSL_TXT_kEDH,0,SSL_kEDH,  0,0,0,0,SSL_MKEY_MASK,0},
      {0,SSL_TXT_kFZA,0,SSL_kFZA,  0,0,0,0,SSL_MKEY_MASK,0},
      {0,SSL_TXT_DH,    0,SSL_DH,    0,0,0,0,SSL_MKEY_MASK,0},
      {0,SSL_TXT_EDH,   0,SSL_EDH,   0,0,0,0,SSL_MKEY_MASK|SSL_AUTH_MASK,0},

      {0,SSL_TXT_aKRB5,0,SSL_aKRB5,0,0,0,0,SSL_AUTH_MASK,0},  /* VRS Kerberos5 */
      {0,SSL_TXT_aRSA,0,SSL_aRSA,  0,0,0,0,SSL_AUTH_MASK,0},
      {0,SSL_TXT_aDSS,0,SSL_aDSS,  0,0,0,0,SSL_AUTH_MASK,0},
      {0,SSL_TXT_aFZA,0,SSL_aFZA,  0,0,0,0,SSL_AUTH_MASK,0},
      {0,SSL_TXT_aNULL,0,SSL_aNULL,0,0,0,0,SSL_AUTH_MASK,0},
      {0,SSL_TXT_aDH, 0,SSL_aDH,   0,0,0,0,SSL_AUTH_MASK,0},
      {0,SSL_TXT_DSS,   0,SSL_DSS,   0,0,0,0,SSL_AUTH_MASK,0},

      {0,SSL_TXT_DES,   0,SSL_DES,   0,0,0,0,SSL_ENC_MASK,0},
      {0,SSL_TXT_3DES,0,SSL_3DES,  0,0,0,0,SSL_ENC_MASK,0},
      {0,SSL_TXT_RC4,   0,SSL_RC4,   0,0,0,0,SSL_ENC_MASK,0},
      {0,SSL_TXT_RC2,   0,SSL_RC2,   0,0,0,0,SSL_ENC_MASK,0},
#ifndef OPENSSL_NO_IDEA
      {0,SSL_TXT_IDEA,0,SSL_IDEA,  0,0,0,0,SSL_ENC_MASK,0},
#endif
      {0,SSL_TXT_eNULL,0,SSL_eNULL,0,0,0,0,SSL_ENC_MASK,0},
      {0,SSL_TXT_eFZA,0,SSL_eFZA,  0,0,0,0,SSL_ENC_MASK,0},
      {0,SSL_TXT_AES,   0,SSL_AES,   0,0,0,0,SSL_ENC_MASK,0},

      {0,SSL_TXT_MD5,   0,SSL_MD5,   0,0,0,0,SSL_MAC_MASK,0},
      {0,SSL_TXT_SHA1,0,SSL_SHA1,  0,0,0,0,SSL_MAC_MASK,0},
      {0,SSL_TXT_SHA,   0,SSL_SHA,   0,0,0,0,SSL_MAC_MASK,0},

      {0,SSL_TXT_NULL,0,SSL_NULL,  0,0,0,0,SSL_ENC_MASK,0},
      {0,SSL_TXT_KRB5,0,SSL_KRB5,  0,0,0,0,SSL_AUTH_MASK|SSL_MKEY_MASK,0},
      {0,SSL_TXT_RSA,   0,SSL_RSA,   0,0,0,0,SSL_AUTH_MASK|SSL_MKEY_MASK,0},
      {0,SSL_TXT_ADH,   0,SSL_ADH,   0,0,0,0,SSL_AUTH_MASK|SSL_MKEY_MASK,0},
      {0,SSL_TXT_FZA,   0,SSL_FZA,   0,0,0,0,SSL_AUTH_MASK|SSL_MKEY_MASK|SSL_ENC_MASK,0},

      {0,SSL_TXT_SSLV2, 0,SSL_SSLV2, 0,0,0,0,SSL_SSL_MASK,0},
      {0,SSL_TXT_SSLV3, 0,SSL_SSLV3, 0,0,0,0,SSL_SSL_MASK,0},
      {0,SSL_TXT_TLSV1, 0,SSL_TLSV1, 0,0,0,0,SSL_SSL_MASK,0},

      {0,SSL_TXT_EXP   ,0, 0,SSL_EXPORT, 0,0,0,0,SSL_EXP_MASK},
      {0,SSL_TXT_EXPORT,0, 0,SSL_EXPORT, 0,0,0,0,SSL_EXP_MASK},
      {0,SSL_TXT_EXP40, 0, 0, SSL_EXP40, 0,0,0,0,SSL_STRONG_MASK},
      {0,SSL_TXT_EXP56, 0, 0, SSL_EXP56, 0,0,0,0,SSL_STRONG_MASK},
      {0,SSL_TXT_LOW,   0, 0,   SSL_LOW, 0,0,0,0,SSL_STRONG_MASK},
      {0,SSL_TXT_MEDIUM,0, 0,SSL_MEDIUM, 0,0,0,0,SSL_STRONG_MASK},
      {0,SSL_TXT_HIGH,  0, 0,  SSL_HIGH, 0,0,0,0,SSL_STRONG_MASK},
      {0,SSL_TXT_FIPS,  0, 0,  SSL_FIPS, 0,0,0,0,SSL_FIPS|SSL_STRONG_NONE},
      };

static int init_ciphers=1;

static void load_ciphers(void)
      {
      ssl_cipher_methods[SSL_ENC_DES_IDX]= 
            EVP_get_cipherbyname(SN_des_cbc);
      ssl_cipher_methods[SSL_ENC_3DES_IDX]=
            EVP_get_cipherbyname(SN_des_ede3_cbc);
      ssl_cipher_methods[SSL_ENC_RC4_IDX]=
            EVP_get_cipherbyname(SN_rc4);
      ssl_cipher_methods[SSL_ENC_RC2_IDX]= 
            EVP_get_cipherbyname(SN_rc2_cbc);
#ifndef OPENSSL_NO_IDEA
      ssl_cipher_methods[SSL_ENC_IDEA_IDX]= 
            EVP_get_cipherbyname(SN_idea_cbc);
#else
      ssl_cipher_methods[SSL_ENC_IDEA_IDX]= NULL;
#endif
      ssl_cipher_methods[SSL_ENC_AES128_IDX]=
        EVP_get_cipherbyname(SN_aes_128_cbc);
      ssl_cipher_methods[SSL_ENC_AES256_IDX]=
        EVP_get_cipherbyname(SN_aes_256_cbc);

      ssl_digest_methods[SSL_MD_MD5_IDX]=
            EVP_get_digestbyname(SN_md5);
      ssl_digest_methods[SSL_MD_SHA1_IDX]=
            EVP_get_digestbyname(SN_sha1);
      init_ciphers=0;
      }

int ssl_cipher_get_evp(SSL_SESSION *s, const EVP_CIPHER **enc,
           const EVP_MD **md, SSL_COMP **comp)
      {
      int i;
      SSL_CIPHER *c;

      c=s->cipher;
      if (c == NULL) return(0);
      if (comp != NULL)
            {
            SSL_COMP ctmp;

            if (s->compress_meth == 0)
                  *comp=NULL;
            else if (ssl_comp_methods == NULL)
                  {
                  /* bad */
                  *comp=NULL;
                  }
            else
                  {

                  ctmp.id=s->compress_meth;
                  i=sk_SSL_COMP_find(ssl_comp_methods,&ctmp);
                  if (i >= 0)
                        *comp=sk_SSL_COMP_value(ssl_comp_methods,i);
                  else
                        *comp=NULL;
                  }
            }

      if ((enc == NULL) || (md == NULL)) return(0);

      switch (c->algorithms & SSL_ENC_MASK)
            {
      case SSL_DES:
            i=SSL_ENC_DES_IDX;
            break;
      case SSL_3DES:
            i=SSL_ENC_3DES_IDX;
            break;
      case SSL_RC4:
            i=SSL_ENC_RC4_IDX;
            break;
      case SSL_RC2:
            i=SSL_ENC_RC2_IDX;
            break;
      case SSL_IDEA:
            i=SSL_ENC_IDEA_IDX;
            break;
      case SSL_eNULL:
            i=SSL_ENC_NULL_IDX;
            break;
      case SSL_AES:
            switch(c->alg_bits)
                  {
            case 128: i=SSL_ENC_AES128_IDX; break;
            case 256: i=SSL_ENC_AES256_IDX; break;
            default: i=-1; break;
                  }
            break;
      default:
            i= -1;
            break;
            }

      if ((i < 0) || (i > SSL_ENC_NUM_IDX))
            *enc=NULL;
      else
            {
            if (i == SSL_ENC_NULL_IDX)
                  *enc=EVP_enc_null();
            else
                  *enc=ssl_cipher_methods[i];
            }

      switch (c->algorithms & SSL_MAC_MASK)
            {
      case SSL_MD5:
            i=SSL_MD_MD5_IDX;
            break;
      case SSL_SHA1:
            i=SSL_MD_SHA1_IDX;
            break;
      default:
            i= -1;
            break;
            }
      if ((i < 0) || (i > SSL_MD_NUM_IDX))
            *md=NULL;
      else
            *md=ssl_digest_methods[i];

      if ((*enc != NULL) && (*md != NULL))
            return(1);
      else
            return(0);
      }

#define ITEM_SEP(a) \
      (((a) == ':') || ((a) == ' ') || ((a) == ';') || ((a) == ','))

static void ll_append_tail(CIPHER_ORDER **head, CIPHER_ORDER *curr,
           CIPHER_ORDER **tail)
      {
      if (curr == *tail) return;
      if (curr == *head)
            *head=curr->next;
      if (curr->prev != NULL)
            curr->prev->next=curr->next;
      if (curr->next != NULL) /* should always be true */
            curr->next->prev=curr->prev;
      (*tail)->next=curr;
      curr->prev= *tail;
      curr->next=NULL;
      *tail=curr;
      }

static unsigned long ssl_cipher_get_disabled(void)
      {
      unsigned long mask;

      mask = SSL_kFZA;
#ifdef OPENSSL_NO_RSA
      mask |= SSL_aRSA|SSL_kRSA;
#endif
#ifdef OPENSSL_NO_DSA
      mask |= SSL_aDSS;
#endif
#ifdef OPENSSL_NO_DH
      mask |= SSL_kDHr|SSL_kDHd|SSL_kEDH|SSL_aDH;
#endif
#ifdef OPENSSL_NO_KRB5
      mask |= SSL_kKRB5|SSL_aKRB5;
#endif

#ifdef SSL_FORBID_ENULL
      mask |= SSL_eNULL;
#endif

      mask |= (ssl_cipher_methods[SSL_ENC_DES_IDX ] == NULL) ? SSL_DES :0;
      mask |= (ssl_cipher_methods[SSL_ENC_3DES_IDX] == NULL) ? SSL_3DES:0;
      mask |= (ssl_cipher_methods[SSL_ENC_RC4_IDX ] == NULL) ? SSL_RC4 :0;
      mask |= (ssl_cipher_methods[SSL_ENC_RC2_IDX ] == NULL) ? SSL_RC2 :0;
      mask |= (ssl_cipher_methods[SSL_ENC_IDEA_IDX] == NULL) ? SSL_IDEA:0;
      mask |= (ssl_cipher_methods[SSL_ENC_eFZA_IDX] == NULL) ? SSL_eFZA:0;
      mask |= (ssl_cipher_methods[SSL_ENC_AES128_IDX] == NULL) ? SSL_AES:0;

      mask |= (ssl_digest_methods[SSL_MD_MD5_IDX ] == NULL) ? SSL_MD5 :0;
      mask |= (ssl_digest_methods[SSL_MD_SHA1_IDX] == NULL) ? SSL_SHA1:0;

      return(mask);
      }

static void ssl_cipher_collect_ciphers(const SSL_METHOD *ssl_method,
            int num_of_ciphers, unsigned long mask, CIPHER_ORDER *co_list,
            CIPHER_ORDER **head_p, CIPHER_ORDER **tail_p)
      {
      int i, co_list_num;
      SSL_CIPHER *c;

      /*
       * We have num_of_ciphers descriptions compiled in, depending on the
       * method selected (SSLv2 and/or SSLv3, TLSv1 etc).
       * These will later be sorted in a linked list with at most num
       * entries.
       */

      /* Get the initial list of ciphers */
      co_list_num = 0;  /* actual count of ciphers */
      for (i = 0; i < num_of_ciphers; i++)
            {
            c = ssl_method->get_cipher(i);
            /* drop those that use any of that is not available */
#ifdef OPENSSL_FIPS
            if ((c != NULL) && c->valid && !(c->algorithms & mask)
                  && (!FIPS_mode() || (c->algo_strength & SSL_FIPS)))
#else
            if ((c != NULL) && c->valid && !(c->algorithms & mask))
#endif
                  {
                  co_list[co_list_num].cipher = c;
                  co_list[co_list_num].next = NULL;
                  co_list[co_list_num].prev = NULL;
                  co_list[co_list_num].active = 0;
                  co_list_num++;
#ifdef KSSL_DEBUG
                  printf("\t%d: %s %lx %lx\n",i,c->name,c->id,c->algorithms);
#endif      /* KSSL_DEBUG */
                  /*
                  if (!sk_push(ca_list,(char *)c)) goto err;
                  */
                  }
            }

      /*
       * Prepare linked list from list entries
       */   
      for (i = 1; i < co_list_num - 1; i++)
            {
            co_list[i].prev = &(co_list[i-1]);
            co_list[i].next = &(co_list[i+1]);
            }
      if (co_list_num > 0)
            {
            (*head_p) = &(co_list[0]);
            (*head_p)->prev = NULL;
            (*head_p)->next = &(co_list[1]);
            (*tail_p) = &(co_list[co_list_num - 1]);
            (*tail_p)->prev = &(co_list[co_list_num - 2]);
            (*tail_p)->next = NULL;
            }
      }

static void ssl_cipher_collect_aliases(SSL_CIPHER **ca_list,
                  int num_of_group_aliases, unsigned long mask,
                  CIPHER_ORDER *head)
      {
      CIPHER_ORDER *ciph_curr;
      SSL_CIPHER **ca_curr;
      int i;

      /*
       * First, add the real ciphers as already collected
       */
      ciph_curr = head;
      ca_curr = ca_list;
      while (ciph_curr != NULL)
            {
            *ca_curr = ciph_curr->cipher;
            ca_curr++;
            ciph_curr = ciph_curr->next;
            }

      /*
       * Now we add the available ones from the cipher_aliases[] table.
       * They represent either an algorithm, that must be fully
       * supported (not match any bit in mask) or represent a cipher
       * strength value (will be added in any case because algorithms=0).
       */
      for (i = 0; i < num_of_group_aliases; i++)
            {
            if ((i == 0) ||         /* always fetch "ALL" */
                !(cipher_aliases[i].algorithms & mask))
                  {
                  *ca_curr = (SSL_CIPHER *)(cipher_aliases + i);
                  ca_curr++;
                  }
            }

      *ca_curr = NULL;  /* end of list */
      }

static void ssl_cipher_apply_rule(unsigned long algorithms, unsigned long mask,
            unsigned long algo_strength, unsigned long mask_strength,
            int rule, int strength_bits, CIPHER_ORDER *co_list,
            CIPHER_ORDER **head_p, CIPHER_ORDER **tail_p)
      {
      CIPHER_ORDER *head, *tail, *curr, *curr2, *tail2;
      SSL_CIPHER *cp;
      unsigned long ma, ma_s;

#ifdef CIPHER_DEBUG
      printf("Applying rule %d with %08lx %08lx %08lx %08lx (%d)\n",
            rule, algorithms, mask, algo_strength, mask_strength,
            strength_bits);
#endif

      curr = head = *head_p;
      curr2 = head;
      tail2 = tail = *tail_p;
      for (;;)
            {
            if ((curr == NULL) || (curr == tail2)) break;
            curr = curr2;
            curr2 = curr->next;

            cp = curr->cipher;

            /*
             * Selection criteria is either the number of strength_bits
             * or the algorithm used.
             */
            if (strength_bits == -1)
                  {
                  ma = mask & cp->algorithms;
                  ma_s = mask_strength & cp->algo_strength;

#ifdef CIPHER_DEBUG
                  printf("\nName: %s:\nAlgo = %08lx Algo_strength = %08lx\nMask = %08lx Mask_strength %08lx\n", cp->name, cp->algorithms, cp->algo_strength, mask, mask_strength);
                  printf("ma = %08lx ma_s %08lx, ma&algo=%08lx, ma_s&algos=%08lx\n", ma, ma_s, ma&algorithms, ma_s&algo_strength);
#endif
                  /*
                   * Select: if none of the mask bit was met from the
                   * cipher or not all of the bits were met, the
                   * selection does not apply.
                   */
                  if (((ma == 0) && (ma_s == 0)) ||
                      ((ma & algorithms) != ma) ||
                      ((ma_s & algo_strength) != ma_s))
                        continue; /* does not apply */
                  }
            else if (strength_bits != cp->strength_bits)
                  continue;   /* does not apply */

#ifdef CIPHER_DEBUG
            printf("Action = %d\n", rule);
#endif

            /* add the cipher if it has not been added yet. */
            if (rule == CIPHER_ADD)
                  {
                  if (!curr->active)
                        {
                        ll_append_tail(&head, curr, &tail);
                        curr->active = 1;
                        }
                  }
            /* Move the added cipher to this location */
            else if (rule == CIPHER_ORD)
                  {
                  if (curr->active)
                        {
                        ll_append_tail(&head, curr, &tail);
                        }
                  }
            else if     (rule == CIPHER_DEL)
                  curr->active = 0;
            else if (rule == CIPHER_KILL)
                  {
                  if (head == curr)
                        head = curr->next;
                  else
                        curr->prev->next = curr->next;
                  if (tail == curr)
                        tail = curr->prev;
                  curr->active = 0;
                  if (curr->next != NULL)
                        curr->next->prev = curr->prev;
                  if (curr->prev != NULL)
                        curr->prev->next = curr->next;
                  curr->next = NULL;
                  curr->prev = NULL;
                  }
            }

      *head_p = head;
      *tail_p = tail;
      }

static int ssl_cipher_strength_sort(CIPHER_ORDER *co_list,
                            CIPHER_ORDER **head_p,
                            CIPHER_ORDER **tail_p)
      {
      int max_strength_bits, i, *number_uses;
      CIPHER_ORDER *curr;

      /*
       * This routine sorts the ciphers with descending strength. The sorting
       * must keep the pre-sorted sequence, so we apply the normal sorting
       * routine as '+' movement to the end of the list.
       */
      max_strength_bits = 0;
      curr = *head_p;
      while (curr != NULL)
            {
            if (curr->active &&
                (curr->cipher->strength_bits > max_strength_bits))
                max_strength_bits = curr->cipher->strength_bits;
            curr = curr->next;
            }

      number_uses = OPENSSL_malloc((max_strength_bits + 1) * sizeof(int));
      if (!number_uses)
      {
            SSLerr(SSL_F_SSL_CIPHER_STRENGTH_SORT,ERR_R_MALLOC_FAILURE);
            return(0);
      }
      memset(number_uses, 0, (max_strength_bits + 1) * sizeof(int));

      /*
       * Now find the strength_bits values actually used
       */
      curr = *head_p;
      while (curr != NULL)
            {
            if (curr->active)
                  number_uses[curr->cipher->strength_bits]++;
            curr = curr->next;
            }
      /*
       * Go through the list of used strength_bits values in descending
       * order.
       */
      for (i = max_strength_bits; i >= 0; i--)
            if (number_uses[i] > 0)
                  ssl_cipher_apply_rule(0, 0, 0, 0, CIPHER_ORD, i,
                              co_list, head_p, tail_p);

      OPENSSL_free(number_uses);
      return(1);
      }

static int ssl_cipher_process_rulestr(const char *rule_str,
            CIPHER_ORDER *co_list, CIPHER_ORDER **head_p,
            CIPHER_ORDER **tail_p, SSL_CIPHER **ca_list)
      {
      unsigned long algorithms, mask, algo_strength, mask_strength;
      const char *l, *start, *buf;
      int j, multi, found, rule, retval, ok, buflen;
      char ch;

      retval = 1;
      l = rule_str;
      for (;;)
            {
            ch = *l;

            if (ch == '\0')
                  break;            /* done */
            if (ch == '-')
                  { rule = CIPHER_DEL; l++; }
            else if (ch == '+')
                  { rule = CIPHER_ORD; l++; }
            else if (ch == '!')
                  { rule = CIPHER_KILL; l++; }
            else if (ch == '@')
                  { rule = CIPHER_SPECIAL; l++; }
            else
                  { rule = CIPHER_ADD; }

            if (ITEM_SEP(ch))
                  {
                  l++;
                  continue;
                  }

            algorithms = mask = algo_strength = mask_strength = 0;

            start=l;
            for (;;)
                  {
                  ch = *l;
                  buf = l;
                  buflen = 0;
#ifndef CHARSET_EBCDIC
                  while (     ((ch >= 'A') && (ch <= 'Z')) ||
                        ((ch >= '0') && (ch <= '9')) ||
                        ((ch >= 'a') && (ch <= 'z')) ||
                         (ch == '-'))
#else
                  while (     isalnum(ch) || (ch == '-'))
#endif
                         {
                         ch = *(++l);
                         buflen++;
                         }

                  if (buflen == 0)
                        {
                        /*
                         * We hit something we cannot deal with,
                         * it is no command or separator nor
                         * alphanumeric, so we call this an error.
                         */
                        SSLerr(SSL_F_SSL_CIPHER_PROCESS_RULESTR,
                               SSL_R_INVALID_COMMAND);
                        retval = found = 0;
                        l++;
                        break;
                        }

                  if (rule == CIPHER_SPECIAL)
                        {
                        found = 0; /* unused -- avoid compiler warning */
                        break;      /* special treatment */
                        }

                  /* check for multi-part specification */
                  if (ch == '+')
                        {
                        multi=1;
                        l++;
                        }
                  else
                        multi=0;

                  /*
                   * Now search for the cipher alias in the ca_list. Be careful
                   * with the strncmp, because the "buflen" limitation
                   * will make the rule "ADH:SOME" and the cipher
                   * "ADH-MY-CIPHER" look like a match for buflen=3.
                   * So additionally check whether the cipher name found
                   * has the correct length. We can save a strlen() call:
                   * just checking for the '\0' at the right place is
                   * sufficient, we have to strncmp() anyway. (We cannot
                   * use strcmp(), because buf is not '\0' terminated.)
                   */
                   j = found = 0;
                   while (ca_list[j])
                        {
                        if (!strncmp(buf, ca_list[j]->name, buflen) &&
                            (ca_list[j]->name[buflen] == '\0'))
                              {
                              found = 1;
                              break;
                              }
                        else
                              j++;
                        }
                  if (!found)
                        break;      /* ignore this entry */

                  algorithms |= ca_list[j]->algorithms;
                  mask |= ca_list[j]->mask;
                  algo_strength |= ca_list[j]->algo_strength;
                  mask_strength |= ca_list[j]->mask_strength;

                  if (!multi) break;
                  }

            /*
             * Ok, we have the rule, now apply it
             */
            if (rule == CIPHER_SPECIAL)
                  {     /* special command */
                  ok = 0;
                  if ((buflen == 8) &&
                        !strncmp(buf, "STRENGTH", 8))
                        ok = ssl_cipher_strength_sort(co_list,
                              head_p, tail_p);
                  else
                        SSLerr(SSL_F_SSL_CIPHER_PROCESS_RULESTR,
                              SSL_R_INVALID_COMMAND);
                  if (ok == 0)
                        retval = 0;
                  /*
                   * We do not support any "multi" options
                   * together with "@", so throw away the
                   * rest of the command, if any left, until
                   * end or ':' is found.
                   */
                  while ((*l != '\0') && ITEM_SEP(*l))
                        l++;
                  }
            else if (found)
                  {
                  ssl_cipher_apply_rule(algorithms, mask,
                        algo_strength, mask_strength, rule, -1,
                        co_list, head_p, tail_p);
                  }
            else
                  {
                  while ((*l != '\0') && ITEM_SEP(*l))
                        l++;
                  }
            if (*l == '\0') break; /* done */
            }

      return(retval);
      }

STACK_OF(SSL_CIPHER) *ssl_create_cipher_list(const SSL_METHOD *ssl_method,
            STACK_OF(SSL_CIPHER) **cipher_list,
            STACK_OF(SSL_CIPHER) **cipher_list_by_id,
            const char *rule_str)
      {
      int ok, num_of_ciphers, num_of_alias_max, num_of_group_aliases;
      unsigned long disabled_mask;
      STACK_OF(SSL_CIPHER) *cipherstack;
      const char *rule_p;
      CIPHER_ORDER *co_list = NULL, *head = NULL, *tail = NULL, *curr;
      SSL_CIPHER **ca_list = NULL;

      /*
       * Return with error if nothing to do.
       */
      if (rule_str == NULL) return(NULL);

      if (init_ciphers)
            {
            CRYPTO_w_lock(CRYPTO_LOCK_SSL);
            if (init_ciphers) load_ciphers();
            CRYPTO_w_unlock(CRYPTO_LOCK_SSL);
            }

      /*
       * To reduce the work to do we only want to process the compiled
       * in algorithms, so we first get the mask of disabled ciphers.
       */
      disabled_mask = ssl_cipher_get_disabled();

      /*
       * Now we have to collect the available ciphers from the compiled
       * in ciphers. We cannot get more than the number compiled in, so
       * it is used for allocation.
       */
      num_of_ciphers = ssl_method->num_ciphers();
#ifdef KSSL_DEBUG
      printf("ssl_create_cipher_list() for %d ciphers\n", num_of_ciphers);
#endif    /* KSSL_DEBUG */
      co_list = (CIPHER_ORDER *)OPENSSL_malloc(sizeof(CIPHER_ORDER) * num_of_ciphers);
      if (co_list == NULL)
            {
            SSLerr(SSL_F_SSL_CREATE_CIPHER_LIST,ERR_R_MALLOC_FAILURE);
            return(NULL);     /* Failure */
            }

      ssl_cipher_collect_ciphers(ssl_method, num_of_ciphers, disabled_mask,
                           co_list, &head, &tail);

      /*
       * We also need cipher aliases for selecting based on the rule_str.
       * There might be two types of entries in the rule_str: 1) names
       * of ciphers themselves 2) aliases for groups of ciphers.
       * For 1) we need the available ciphers and for 2) the cipher
       * groups of cipher_aliases added together in one list (otherwise
       * we would be happy with just the cipher_aliases table).
       */
      num_of_group_aliases = sizeof(cipher_aliases) / sizeof(SSL_CIPHER);
      num_of_alias_max = num_of_ciphers + num_of_group_aliases + 1;
      ca_list =
            (SSL_CIPHER **)OPENSSL_malloc(sizeof(SSL_CIPHER *) * num_of_alias_max);
      if (ca_list == NULL)
            {
            OPENSSL_free(co_list);
            SSLerr(SSL_F_SSL_CREATE_CIPHER_LIST,ERR_R_MALLOC_FAILURE);
            return(NULL);     /* Failure */
            }
      ssl_cipher_collect_aliases(ca_list, num_of_group_aliases, disabled_mask,
                           head);

      /*
       * If the rule_string begins with DEFAULT, apply the default rule
       * before using the (possibly available) additional rules.
       */
      ok = 1;
      rule_p = rule_str;
      if (strncmp(rule_str,"DEFAULT",7) == 0)
            {
            ok = ssl_cipher_process_rulestr(SSL_DEFAULT_CIPHER_LIST,
                  co_list, &head, &tail, ca_list);
            rule_p += 7;
            if (*rule_p == ':')
                  rule_p++;
            }

      if (ok && (strlen(rule_p) > 0))
            ok = ssl_cipher_process_rulestr(rule_p, co_list, &head, &tail,
                                    ca_list);

      OPENSSL_free(ca_list);  /* Not needed anymore */

      if (!ok)
            {     /* Rule processing failure */
            OPENSSL_free(co_list);
            return(NULL);
            }
      /*
       * Allocate new "cipherstack" for the result, return with error
       * if we cannot get one.
       */
      if ((cipherstack = sk_SSL_CIPHER_new_null()) == NULL)
            {
            OPENSSL_free(co_list);
            return(NULL);
            }

      /*
       * The cipher selection for the list is done. The ciphers are added
       * to the resulting precedence to the STACK_OF(SSL_CIPHER).
       */
      for (curr = head; curr != NULL; curr = curr->next)
            {
#ifdef OPENSSL_FIPS
            if (curr->active && (!FIPS_mode() || curr->cipher->algo_strength & SSL_FIPS))
#else
            if (curr->active)
#endif
                  {
                  sk_SSL_CIPHER_push(cipherstack, curr->cipher);
#ifdef CIPHER_DEBUG
                  printf("<%s>\n",curr->cipher->name);
#endif
                  }
            }
      OPENSSL_free(co_list);  /* Not needed any longer */

      /*
       * The following passage is a little bit odd. If pointer variables
       * were supplied to hold STACK_OF(SSL_CIPHER) return information,
       * the old memory pointed to is free()ed. Then, however, the
       * cipher_list entry will be assigned just a copy of the returned
       * cipher stack. For cipher_list_by_id a copy of the cipher stack
       * will be created. See next comment...
       */
      if (cipher_list != NULL)
            {
            if (*cipher_list != NULL)
                  sk_SSL_CIPHER_free(*cipher_list);
            *cipher_list = cipherstack;
            }

      if (cipher_list_by_id != NULL)
            {
            if (*cipher_list_by_id != NULL)
                  sk_SSL_CIPHER_free(*cipher_list_by_id);
            *cipher_list_by_id = sk_SSL_CIPHER_dup(cipherstack);
            }

      /*
       * Now it is getting really strange. If something failed during
       * the previous pointer assignment or if one of the pointers was
       * not requested, the error condition is met. That might be
       * discussable. The strange thing is however that in this case
       * the memory "ret" pointed to is "free()ed" and hence the pointer
       * cipher_list becomes wild. The memory reserved for
       * cipher_list_by_id however is not "free()ed" and stays intact.
       */
      if (  (cipher_list_by_id == NULL) ||
            (*cipher_list_by_id == NULL) ||
            (cipher_list == NULL) ||
            (*cipher_list == NULL))
            {
            sk_SSL_CIPHER_free(cipherstack);
            return(NULL);
            }

      sk_SSL_CIPHER_set_cmp_func(*cipher_list_by_id,ssl_cipher_ptr_id_cmp);

      return(cipherstack);
      }

char *SSL_CIPHER_description(SSL_CIPHER *cipher, char *buf, int len)
      {
      int is_export,pkl,kl;
      char *ver,*exp_str;
      char *kx,*au,*enc,*mac;
      unsigned long alg,alg2,alg_s;
#ifdef KSSL_DEBUG
      static char *format="%-23s %s Kx=%-8s Au=%-4s Enc=%-9s Mac=%-4s%s AL=%lx\n";
#else
      static char *format="%-23s %s Kx=%-8s Au=%-4s Enc=%-9s Mac=%-4s%s\n";
#endif /* KSSL_DEBUG */

      alg=cipher->algorithms;
      alg_s=cipher->algo_strength;
      alg2=cipher->algorithm2;

      is_export=SSL_C_IS_EXPORT(cipher);
      pkl=SSL_C_EXPORT_PKEYLENGTH(cipher);
      kl=SSL_C_EXPORT_KEYLENGTH(cipher);
      exp_str=is_export?" export":"";

      if (alg & SSL_SSLV2)
            ver="SSLv2";
      else if (alg & SSL_SSLV3)
            ver="SSLv3";
      else
            ver="unknown";

      switch (alg&SSL_MKEY_MASK)
            {
      case SSL_kRSA:
            kx=is_export?(pkl == 512 ? "RSA(512)" : "RSA(1024)"):"RSA";
            break;
      case SSL_kDHr:
            kx="DH/RSA";
            break;
      case SSL_kDHd:
            kx="DH/DSS";
            break;
        case SSL_kKRB5:         /* VRS */
        case SSL_KRB5:          /* VRS */
            kx="KRB5";
            break;
      case SSL_kFZA:
            kx="Fortezza";
            break;
      case SSL_kEDH:
            kx=is_export?(pkl == 512 ? "DH(512)" : "DH(1024)"):"DH";
            break;
      default:
            kx="unknown";
            }

      switch (alg&SSL_AUTH_MASK)
            {
      case SSL_aRSA:
            au="RSA";
            break;
      case SSL_aDSS:
            au="DSS";
            break;
      case SSL_aDH:
            au="DH";
            break;
        case SSL_aKRB5:         /* VRS */
        case SSL_KRB5:          /* VRS */
            au="KRB5";
            break;
      case SSL_aFZA:
      case SSL_aNULL:
            au="None";
            break;
      default:
            au="unknown";
            break;
            }

      switch (alg&SSL_ENC_MASK)
            {
      case SSL_DES:
            enc=(is_export && kl == 5)?"DES(40)":"DES(56)";
            break;
      case SSL_3DES:
            enc="3DES(168)";
            break;
      case SSL_RC4:
            enc=is_export?(kl == 5 ? "RC4(40)" : "RC4(56)")
              :((alg2&SSL2_CF_8_BYTE_ENC)?"RC4(64)":"RC4(128)");
            break;
      case SSL_RC2:
            enc=is_export?(kl == 5 ? "RC2(40)" : "RC2(56)"):"RC2(128)";
            break;
      case SSL_IDEA:
            enc="IDEA(128)";
            break;
      case SSL_eFZA:
            enc="Fortezza";
            break;
      case SSL_eNULL:
            enc="None";
            break;
      case SSL_AES:
            switch(cipher->strength_bits)
                  {
            case 128: enc="AES(128)"; break;
            case 192: enc="AES(192)"; break;
            case 256: enc="AES(256)"; break;
            default: enc="AES(?""?""?)"; break;
                  }
            break;
      default:
            enc="unknown";
            break;
            }

      switch (alg&SSL_MAC_MASK)
            {
      case SSL_MD5:
            mac="MD5";
            break;
      case SSL_SHA1:
            mac="SHA1";
            break;
      default:
            mac="unknown";
            break;
            }

      if (buf == NULL)
            {
            len=128;
            buf=OPENSSL_malloc(len);
            if (buf == NULL) return("OPENSSL_malloc Error");
            }
      else if (len < 128)
            return("Buffer too small");

#ifdef KSSL_DEBUG
      BIO_snprintf(buf,len,format,cipher->name,ver,kx,au,enc,mac,exp_str,alg);
#else
      BIO_snprintf(buf,len,format,cipher->name,ver,kx,au,enc,mac,exp_str);
#endif /* KSSL_DEBUG */
      return(buf);
      }

char *SSL_CIPHER_get_version(SSL_CIPHER *c)
      {
      int i;

      if (c == NULL) return("(NONE)");
      i=(int)(c->id>>24L);
      if (i == 3)
            return("TLSv1/SSLv3");
      else if (i == 2)
            return("SSLv2");
      else
            return("unknown");
      }

/* return the actual cipher being used */
const char *SSL_CIPHER_get_name(SSL_CIPHER *c)
      {
      if (c != NULL)
            return(c->name);
      return("(NONE)");
      }

/* number of bits for symmetric cipher */
int SSL_CIPHER_get_bits(SSL_CIPHER *c, int *alg_bits)
      {
      int ret=0;

      if (c != NULL)
            {
            if (alg_bits != NULL) *alg_bits = c->alg_bits;
            ret = c->strength_bits;
            }
      return(ret);
      }

SSL_COMP *ssl3_comp_find(STACK_OF(SSL_COMP) *sk, int n)
      {
      SSL_COMP *ctmp;
      int i,nn;

      if ((n == 0) || (sk == NULL)) return(NULL);
      nn=sk_SSL_COMP_num(sk);
      for (i=0; i<nn; i++)
            {
            ctmp=sk_SSL_COMP_value(sk,i);
            if (ctmp->id == n)
                  return(ctmp);
            }
      return(NULL);
      }

static int sk_comp_cmp(const SSL_COMP * const *a,
                  const SSL_COMP * const *b)
      {
      return((*a)->id-(*b)->id);
      }

STACK_OF(SSL_COMP) *SSL_COMP_get_compression_methods(void)
      {
      return(ssl_comp_methods);
      }

int SSL_COMP_add_compression_method(int id, COMP_METHOD *cm)
      {
      SSL_COMP *comp;
      STACK_OF(SSL_COMP) *sk;

        if (cm == NULL || cm->type == NID_undef)
                return 1;

      MemCheck_off();
      comp=(SSL_COMP *)OPENSSL_malloc(sizeof(SSL_COMP));
      comp->id=id;
      comp->method=cm;
      if (ssl_comp_methods == NULL)
            sk=ssl_comp_methods=sk_SSL_COMP_new(sk_comp_cmp);
      else
            sk=ssl_comp_methods;
      if ((sk == NULL) || !sk_SSL_COMP_push(sk,comp))
            {
            MemCheck_on();
            SSLerr(SSL_F_SSL_COMP_ADD_COMPRESSION_METHOD,ERR_R_MALLOC_FAILURE);
            return(1);
            }
      else
            {
            MemCheck_on();
            return(0);
            }
      }

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