ssl_ciph.c

一个用于点对点传输加密的工具包源码

		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,
					list, head_p, tail_p);

	OPENSSL_free(number_uses);
	return(1);
	}

static int ssl_cipher_process_rulestr(const char *rule_str,
		CIPHER_ORDER *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.
			 */
			 j = found = 0;
			 while (ca_list[j])
				{
				if ((ca_list[j]->name[buflen] == '\0') &&
				    !strncmp(buf, ca_list[j]->name, buflen))
					{
					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(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,
				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 *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) load_ciphers();

	/*
	 * 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();
	list = (CIPHER_ORDER *)OPENSSL_malloc(sizeof(CIPHER_ORDER) * num_of_ciphers);
	if (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,
				   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(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,
			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, list, &head, &tail,
						ca_list);

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

	if (!ok)
		{	/* Rule processing failure */
		OPENSSL_free(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(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)
		{
		if (curr->active)
			{
			sk_SSL_CIPHER_push(cipherstack, curr->cipher);
#ifdef CIPHER_DEBUG
			printf("<%s>\n",curr->cipher->name);
#endif
			}
		}
	OPENSSL_free(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;
	char *kx,*au,*enc,*mac;
	unsigned long alg,alg2,alg_s;
	static char *format="%-23s %s Kx=%-8s Au=%-4s Enc=%-9s Mac=%-4s%s\n";
	
	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=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_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_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;
	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");

	BIO_snprintf(buf,len,format,cipher->name,ver,kx,au,enc,mac,exp);
	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;

	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))
		{
		SSLerr(SSL_F_SSL_COMP_ADD_COMPRESSION_METHOD,ERR_R_MALLOC_FAILURE);
		return(0);
		}
	else
		return(1);
	}