Introduce limits to prevent malicious keys being able to

cause a denial of service.  (CVE-2006-2940)
[Steve Henson, Bodo Moeller]

Fix ASN.1 parsing of certain invalid structures that can result
in a denial of service.  (CVE-2006-2937)  [Steve Henson]

Fix buffer overflow in SSL_get_shared_ciphers() function.
(CVE-2006-3738) [Tavis Ormandy and Will Drewry, Google Security Team]

Fix SSL client code which could crash if connecting to a
malicious SSLv2 server.  (CVE-2006-4343)
[Tavis Ormandy and Will Drewry, Google Security Team]

CHANGES

@@ -4,6 +4,20 @@
 
  Changes between 0.9.8c and 0.9.8d  [xx XXX xxxx]
 
+  *) Introduce limits to prevent malicious keys being able to
+     cause a denial of service.  (CVE-2006-2940)
+     [Steve Henson, Bodo Moeller]
+
+  *) Fix ASN.1 parsing of certain invalid structures that can result
+     in a denial of service.  (CVE-2006-2937)  [Steve Henson]
+
+  *) Fix buffer overflow in SSL_get_shared_ciphers() function. 
+     (CVE-2006-3738) [Tavis Ormandy and Will Drewry, Google Security Team]
+
+  *) Fix SSL client code which could crash if connecting to a
+     malicious SSLv2 server.  (CVE-2006-4343)
+     [Tavis Ormandy and Will Drewry, Google Security Team]
+
   *) Since 0.9.8b, ciphersuite strings naming explicit ciphersuites
      match only those.  Before that, "AES256-SHA" would be interpreted
      as a pattern and match "AES128-SHA" too (since AES128-SHA got

NEWS

@@ -5,6 +5,12 @@
   This file gives a brief overview of the major changes between each OpenSSL
   release. For more details please read the CHANGES file.
 
+  Major changes between OpenSSL 0.9.7c and OpenSSL 0.9.8d:
+
+      o Introduce limits to prevent malicious key DoS  (CVE-2006-2940)
+      o Fix security issues (CVE-2006-2937, CVE-2006-3737, CVE-2006-4343)
+      o Changes to ciphersuite selection algorithm
+
   Major changes between OpenSSL 0.9.8b and OpenSSL 0.9.8c:
 
       o Fix Daniel Bleichenbacher forged signature attack, CVE-2006-4339

crypto/asn1/tasn_dec.c

@@ -832,6 +832,7 @@ static int asn1_d2i_ex_primitive(ASN1_VALUE **pval,
 		}
 	else if (ret == -1)
 		return -1;
+        ret = 0;
 	/* SEQUENCE, SET and "OTHER" are left in encoded form */
 	if ((utype == V_ASN1_SEQUENCE)
 		|| (utype == V_ASN1_SET) || (utype == V_ASN1_OTHER))

crypto/dh/dh.h

@@ -73,6 +73,10 @@
 #include <openssl/bn.h>
 #endif
 	
+#ifndef OPENSSL_DH_MAX_MODULUS_BITS
+# define OPENSSL_DH_MAX_MODULUS_BITS	10000
+#endif
+
 #define DH_FLAG_CACHE_MONT_P     0x01
 #define DH_FLAG_NO_EXP_CONSTTIME 0x02 /* new with 0.9.7h; the built-in DH
                                        * implementation now uses constant time
@@ -221,6 +225,7 @@ void ERR_load_DH_strings(void);
 /* Reason codes. */
 #define DH_R_BAD_GENERATOR				 101
 #define DH_R_INVALID_PUBKEY				 102
+#define DH_R_MODULUS_TOO_LARGE				 103
 #define DH_R_NO_PRIVATE_VALUE				 100
 
 #ifdef  __cplusplus

crypto/dh/dh_err.c

@@ -84,6 +84,7 @@ static ERR_STRING_DATA DH_str_reasons[]=
 	{
 {ERR_REASON(DH_R_BAD_GENERATOR)          ,"bad generator"},
 {ERR_REASON(DH_R_INVALID_PUBKEY)         ,"invalid public key"},
+{ERR_REASON(DH_R_MODULUS_TOO_LARGE)      ,"modulus too large"},
 {ERR_REASON(DH_R_NO_PRIVATE_VALUE)       ,"no private value"},
 {0,NULL}
 	};

crypto/dh/dh_key.c

@@ -179,6 +179,12 @@ static int compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh)
 	int ret= -1;
         int check_result;
 
+	if (BN_num_bits(dh->p) > OPENSSL_DH_MAX_MODULUS_BITS)
+		{
+		DHerr(DH_F_COMPUTE_KEY,DH_R_MODULUS_TOO_LARGE);
+		goto err;
+		}
+
 	ctx = BN_CTX_new();
 	if (ctx == NULL) goto err;
 	BN_CTX_start(ctx);

crypto/dsa/dsa.h

@@ -84,6 +84,10 @@
 #endif
 #endif
 
+#ifndef OPENSSL_DSA_MAX_MODULUS_BITS
+# define OPENSSL_DSA_MAX_MODULUS_BITS	10000
+#endif
+
 #define DSA_FLAG_CACHE_MONT_P	0x01
 #define DSA_FLAG_NO_EXP_CONSTTIME       0x02 /* new with 0.9.7h; the built-in DSA
                                               * implementation now uses constant time
@@ -270,8 +274,10 @@ void ERR_load_DSA_strings(void);
 #define DSA_F_SIG_CB					 114
 
 /* Reason codes. */
+#define DSA_R_BAD_Q_VALUE				 102
 #define DSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE		 100
 #define DSA_R_MISSING_PARAMETERS			 101
+#define DSA_R_MODULUS_TOO_LARGE				 103
 
 #ifdef  __cplusplus
 }

crypto/dsa/dsa_err.c

@@ -89,8 +89,10 @@ static ERR_STRING_DATA DSA_str_functs[]=
 
 static ERR_STRING_DATA DSA_str_reasons[]=
 	{
+{ERR_REASON(DSA_R_BAD_Q_VALUE)           ,"bad q value"},
 {ERR_REASON(DSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE),"data too large for key size"},
 {ERR_REASON(DSA_R_MISSING_PARAMETERS)    ,"missing parameters"},
+{ERR_REASON(DSA_R_MODULUS_TOO_LARGE)     ,"modulus too large"},
 {0,NULL}
 	};
 

crypto/dsa/dsa_ossl.c

@@ -304,6 +304,18 @@ static int dsa_do_verify(const unsigned char *dgst, int dgst_len, DSA_SIG *sig,
 		return -1;
 		}
 
+	if (BN_num_bits(dsa->q) != 160)
+		{
+		DSAerr(DSA_F_DSA_DO_VERIFY,DSA_R_BAD_Q_VALUE);
+		return -1;
+		}
+
+	if (BN_num_bits(dsa->p) > OPENSSL_DSA_MAX_MODULUS_BITS)
+		{
+		DSAerr(DSA_F_DSA_DO_VERIFY,DSA_R_MODULUS_TOO_LARGE);
+		return -1;
+		}
+
 	BN_init(&u1);
 	BN_init(&u2);
 	BN_init(&t1);

crypto/ec/ec.h

@@ -93,6 +93,10 @@ extern "C" {
 #endif
 
 
+#ifndef OPENSSL_ECC_MAX_FIELD_BITS
+# define OPENSSL_ECC_MAX_FIELD_BITS 661
+#endif
+
 typedef enum {
 	/* values as defined in X9.62 (ECDSA) and elsewhere */
 	POINT_CONVERSION_COMPRESSED = 2,
@@ -482,6 +486,7 @@ void ERR_load_EC_strings(void);
 #define EC_R_D2I_ECPKPARAMETERS_FAILURE			 117
 #define EC_R_DISCRIMINANT_IS_ZERO			 118
 #define EC_R_EC_GROUP_NEW_BY_NAME_FAILURE		 119
+#define EC_R_FIELD_TOO_LARGE				 138
 #define EC_R_GROUP2PKPARAMETERS_FAILURE			 120
 #define EC_R_I2D_ECPKPARAMETERS_FAILURE			 121
 #define EC_R_INCOMPATIBLE_OBJECTS			 101
@@ -492,7 +497,9 @@ void ERR_load_EC_strings(void);
 #define EC_R_INVALID_FIELD				 103
 #define EC_R_INVALID_FORM				 104
 #define EC_R_INVALID_GROUP_ORDER			 122
+#define EC_R_INVALID_PENTANOMIAL_BASIS			 132
 #define EC_R_INVALID_PRIVATE_KEY			 123
+#define EC_R_INVALID_TRINOMIAL_BASIS			 137
 #define EC_R_MISSING_PARAMETERS				 124
 #define EC_R_MISSING_PRIVATE_KEY			 125
 #define EC_R_NOT_A_NIST_PRIME				 135

crypto/ec/ec_asn1.c

@@ -741,6 +741,7 @@ static EC_GROUP *ec_asn1_parameters2group(const ECPARAMETERS *params)
 	EC_GROUP		*ret = NULL;
 	BIGNUM			*p = NULL, *a = NULL, *b = NULL;
 	EC_POINT		*point=NULL;
+	long    		field_bits;
 
 	if (!params->fieldID || !params->fieldID->fieldType || 
 	    !params->fieldID->p.ptr)
@@ -779,6 +780,13 @@ static EC_GROUP *ec_asn1_parameters2group(const ECPARAMETERS *params)
 
 		char_two = params->fieldID->p.char_two;
 
+		field_bits = char_two->m;
+		if (field_bits > OPENSSL_ECC_MAX_FIELD_BITS)
+			{
+			ECerr(EC_F_EC_ASN1_PARAMETERS2GROUP, EC_R_FIELD_TOO_LARGE);
+			goto err;
+			}
+
 		if ((p = BN_new()) == NULL)
 			{
 			ECerr(EC_F_EC_ASN1_PARAMETERS2GROUP, ERR_R_MALLOC_FAILURE);
@@ -799,6 +807,13 @@ static EC_GROUP *ec_asn1_parameters2group(const ECPARAMETERS *params)
 				}
 
 			tmp_long = ASN1_INTEGER_get(char_two->p.tpBasis);
+
+			if (!(char_two->m > tmp_long && tmp_long > 0))
+				{
+				ECerr(EC_F_EC_ASN1_PARAMETERS2GROUP, EC_R_INVALID_TRINOMIAL_BASIS);
+				goto err;
+				}
+			
 			/* create the polynomial */
 			if (!BN_set_bit(p, (int)char_two->m))
 				goto err;
@@ -817,6 +832,13 @@ static EC_GROUP *ec_asn1_parameters2group(const ECPARAMETERS *params)
 				ECerr(EC_F_EC_ASN1_PARAMETERS2GROUP, EC_R_ASN1_ERROR);
 				goto err;
 				}
+
+			if (!(char_two->m > penta->k3 && penta->k3 > penta->k2 && penta->k2 > penta->k1 && penta->k1 > 0))
+				{
+				ECerr(EC_F_EC_ASN1_PARAMETERS2GROUP, EC_R_INVALID_PENTANOMIAL_BASIS);
+				goto err;
+				}
+			
 			/* create the polynomial */
 			if (!BN_set_bit(p, (int)char_two->m)) goto err;
 			if (!BN_set_bit(p, (int)penta->k1)) goto err;
@@ -853,6 +875,20 @@ static EC_GROUP *ec_asn1_parameters2group(const ECPARAMETERS *params)
 			ECerr(EC_F_EC_ASN1_PARAMETERS2GROUP, ERR_R_ASN1_LIB);
 			goto err;
 			}
+
+		if (BN_is_negative(p) || BN_is_zero(p))
+			{
+			ECerr(EC_F_EC_ASN1_PARAMETERS2GROUP, EC_R_INVALID_FIELD);
+			goto err;
+			}
+
+		field_bits = BN_num_bits(p);
+		if (field_bits > OPENSSL_ECC_MAX_FIELD_BITS)
+			{
+			ECerr(EC_F_EC_ASN1_PARAMETERS2GROUP, EC_R_FIELD_TOO_LARGE);
+			goto err;
+			}
+
 		/* create the EC_GROUP structure */
 		ret = EC_GROUP_new_curve_GFp(p, a, b, NULL);
 		}
@@ -910,6 +946,16 @@ static EC_GROUP *ec_asn1_parameters2group(const ECPARAMETERS *params)
 		ECerr(EC_F_EC_ASN1_PARAMETERS2GROUP, ERR_R_ASN1_LIB);
 		goto err;
 		}
+	if (BN_is_negative(a) || BN_is_zero(a))
+		{
+		ECerr(EC_F_EC_ASN1_PARAMETERS2GROUP, EC_R_INVALID_GROUP_ORDER);
+		goto err;
+		}
+	if (BN_num_bits(a) > (int)field_bits + 1) /* Hasse bound */
+		{
+		ECerr(EC_F_EC_ASN1_PARAMETERS2GROUP, EC_R_INVALID_GROUP_ORDER);
+		goto err;
+		}
 	
 	/* extract the cofactor (optional) */
 	if (params->cofactor == NULL)

crypto/ec/ec_err.c

@@ -188,6 +188,7 @@ static ERR_STRING_DATA EC_str_reasons[]=
 {ERR_REASON(EC_R_D2I_ECPKPARAMETERS_FAILURE),"d2i ecpkparameters failure"},
 {ERR_REASON(EC_R_DISCRIMINANT_IS_ZERO)   ,"discriminant is zero"},
 {ERR_REASON(EC_R_EC_GROUP_NEW_BY_NAME_FAILURE),"ec group new by name failure"},
+{ERR_REASON(EC_R_FIELD_TOO_LARGE)        ,"field too large"},
 {ERR_REASON(EC_R_GROUP2PKPARAMETERS_FAILURE),"group2pkparameters failure"},
 {ERR_REASON(EC_R_I2D_ECPKPARAMETERS_FAILURE),"i2d ecpkparameters failure"},
 {ERR_REASON(EC_R_INCOMPATIBLE_OBJECTS)   ,"incompatible objects"},
@@ -198,7 +199,9 @@ static ERR_STRING_DATA EC_str_reasons[]=
 {ERR_REASON(EC_R_INVALID_FIELD)          ,"invalid field"},
 {ERR_REASON(EC_R_INVALID_FORM)           ,"invalid form"},
 {ERR_REASON(EC_R_INVALID_GROUP_ORDER)    ,"invalid group order"},
+{ERR_REASON(EC_R_INVALID_PENTANOMIAL_BASIS),"invalid pentanomial basis"},
 {ERR_REASON(EC_R_INVALID_PRIVATE_KEY)    ,"invalid private key"},
+{ERR_REASON(EC_R_INVALID_TRINOMIAL_BASIS),"invalid trinomial basis"},
 {ERR_REASON(EC_R_MISSING_PARAMETERS)     ,"missing parameters"},
 {ERR_REASON(EC_R_MISSING_PRIVATE_KEY)    ,"missing private key"},
 {ERR_REASON(EC_R_NOT_A_NIST_PRIME)       ,"not a NIST prime"},

crypto/rsa/rsa.h

@@ -159,6 +159,17 @@ struct rsa_st
 	BN_BLINDING *mt_blinding;
 	};
 
+#ifndef OPENSSL_RSA_MAX_MODULUS_BITS
+# define OPENSSL_RSA_MAX_MODULUS_BITS	16384
+#endif
+
+#ifndef OPENSSL_RSA_SMALL_MODULUS_BITS
+# define OPENSSL_RSA_SMALL_MODULUS_BITS	3072
+#endif
+#ifndef OPENSSL_RSA_MAX_PUBEXP_BITS
+# define OPENSSL_RSA_MAX_PUBEXP_BITS	64 /* exponent limit enforced for "large" modulus only */
+#endif
+
 #define RSA_3	0x3L
 #define RSA_F4	0x10001L
 
@@ -407,6 +418,7 @@ void ERR_load_RSA_strings(void);
 #define RSA_R_IQMP_NOT_INVERSE_OF_Q			 126
 #define RSA_R_KEY_SIZE_TOO_SMALL			 120
 #define RSA_R_LAST_OCTET_INVALID			 134
+#define RSA_R_MODULUS_TOO_LARGE				 105
 #define RSA_R_NO_PUBLIC_EXPONENT			 140
 #define RSA_R_NULL_BEFORE_BLOCK_MISSING			 113
 #define RSA_R_N_DOES_NOT_EQUAL_P_Q			 127

crypto/rsa/rsa_eay.c

@@ -168,6 +168,28 @@ static int RSA_eay_public_encrypt(int flen, const unsigned char *from,
 	unsigned char *buf=NULL;
 	BN_CTX *ctx=NULL;
 
+	if (BN_num_bits(rsa->n) > OPENSSL_RSA_MAX_MODULUS_BITS)
+		{
+		RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT, RSA_R_MODULUS_TOO_LARGE);
+		return -1;
+		}
+
+	if (BN_ucmp(rsa->n, rsa->e) <= 0)
+		{
+		RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT, RSA_R_BAD_E_VALUE);
+		return -1;
+		}
+
+	/* for large moduli, enforce exponent limit */
+	if (BN_num_bits(rsa->n) > OPENSSL_RSA_SMALL_MODULUS_BITS)
+		{
+		if (BN_num_bits(rsa->e) > OPENSSL_RSA_MAX_PUBEXP_BITS)
+			{
+			RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT, RSA_R_BAD_E_VALUE);
+			return -1;
+			}
+		}
+	
 	if ((ctx=BN_CTX_new()) == NULL) goto err;
 	BN_CTX_start(ctx);
 	f = BN_CTX_get(ctx);
@@ -597,6 +619,28 @@ static int RSA_eay_public_decrypt(int flen, const unsigned char *from,
 	unsigned char *buf=NULL;
 	BN_CTX *ctx=NULL;
 
+	if (BN_num_bits(rsa->n) > OPENSSL_RSA_MAX_MODULUS_BITS)
+		{
+		RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, RSA_R_MODULUS_TOO_LARGE);
+		return -1;
+		}
+
+	if (BN_ucmp(rsa->n, rsa->e) <= 0)
+		{
+		RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, RSA_R_BAD_E_VALUE);
+		return -1;
+		}
+
+	/* for large moduli, enforce exponent limit */
+	if (BN_num_bits(rsa->n) > OPENSSL_RSA_SMALL_MODULUS_BITS)
+		{
+		if (BN_num_bits(rsa->e) > OPENSSL_RSA_MAX_PUBEXP_BITS)
+			{
+			RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, RSA_R_BAD_E_VALUE);
+			return -1;
+			}
+		}
+	
 	if((ctx = BN_CTX_new()) == NULL) goto err;
 	BN_CTX_start(ctx);
 	f = BN_CTX_get(ctx);

crypto/rsa/rsa_err.c

@@ -137,6 +137,7 @@ static ERR_STRING_DATA RSA_str_reasons[]=
 {ERR_REASON(RSA_R_IQMP_NOT_INVERSE_OF_Q) ,"iqmp not inverse of q"},
 {ERR_REASON(RSA_R_KEY_SIZE_TOO_SMALL)    ,"key size too small"},
 {ERR_REASON(RSA_R_LAST_OCTET_INVALID)    ,"last octet invalid"},
+{ERR_REASON(RSA_R_MODULUS_TOO_LARGE)     ,"modulus too large"},
 {ERR_REASON(RSA_R_NO_PUBLIC_EXPONENT)    ,"no public exponent"},
 {ERR_REASON(RSA_R_NULL_BEFORE_BLOCK_MISSING),"null before block missing"},
 {ERR_REASON(RSA_R_N_DOES_NOT_EQUAL_P_Q)  ,"n does not equal p q"},

ssl/s2_clnt.c

@@ -520,7 +520,8 @@ static int get_server_hello(SSL *s)
 		CRYPTO_add(&s->session->peer->references, 1, CRYPTO_LOCK_X509);
 		}
 
-	if (s->session->peer != s->session->sess_cert->peer_key->x509)
+	if (s->session->sess_cert == NULL 
+      || s->session->peer != s->session->sess_cert->peer_key->x509)
 		/* can't happen */
 		{
 		ssl2_return_error(s, SSL2_PE_UNDEFINED_ERROR);

ssl/s3_srvr.c

@@ -2003,7 +2003,7 @@ int ssl3_get_client_key_exchange(SSL *s)
 
                 if (kssl_ctx->client_princ)
                         {
-                        int len = strlen(kssl_ctx->client_princ);
+                        size_t len = strlen(kssl_ctx->client_princ);
                         if ( len < SSL_MAX_KRB5_PRINCIPAL_LENGTH ) 
                                 {
                                 s->session->krb5_client_princ_len = len;

ssl/ssl_lib.c

@@ -1219,7 +1219,7 @@ char *SSL_get_shared_ciphers(const SSL *s,char *buf,int len)
 		c=sk_SSL_CIPHER_value(sk,i);
 		for (cp=c->name; *cp; )
 			{
-			if (len-- == 0)
+			if (len-- <= 0)
 				{
 				*p='\0';
 				return(buf);