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 0.9.7k and 0.9.7l  [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]
+
   *) Change ciphersuite string processing so that an explicit
      ciphersuite selects this one ciphersuite (so that "AES256-SHA"
      will no longer include "AES128-SHA"), and any other similar

NEWS

@@ -5,6 +5,11 @@
   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 0.9.7k and OpenSSL 0.9.7l:
+
+      o Introduce limits to prevent malicious key DoS  (CVE-2006-2940)
+      o Fix security issues (CVE-2006-2937, CVE-2006-3737, CVE-2006-4343)
+
   Major changes between OpenSSL 0.9.7j and OpenSSL 0.9.7k:
 
       o Fix Daniel Bleichenbacher forged signature attack, CVE-2006-4339

crypto/asn1/tasn_dec.c

@@ -629,6 +629,7 @@ static int asn1_d2i_ex_primitive(ASN1_VALUE **pval, unsigned char **in, long inl
 		ASN1err(ASN1_F_ASN1_D2I_EX_PRIMITIVE, ERR_R_NESTED_ASN1_ERROR);
 		return 0;
 	} 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)) {
 		/* Clear context cache for type OTHER because the auto clear when

crypto/dh/dh.h

@@ -70,6 +70,10 @@
 #include <openssl/crypto.h>
 #include <openssl/ossl_typ.h>
 	
+#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
@@ -207,6 +211,7 @@ void ERR_load_DH_strings(void);
 /* Reason codes. */
 #define DH_R_BAD_GENERATOR				 101
 #define DH_R_NO_PRIVATE_VALUE				 100
+#define DH_R_MODULUS_TOO_LARGE                           103
 
 #ifdef  __cplusplus
 }

crypto/dh/dh_err.c

@@ -82,6 +82,7 @@ static ERR_STRING_DATA DH_str_functs[]=
 static ERR_STRING_DATA DH_str_reasons[]=
 	{
 {ERR_REASON(DH_R_BAD_GENERATOR)          ,"bad generator"},
+{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

@@ -180,6 +180,12 @@ static int compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh)
 	BIGNUM *tmp;
 	int ret= -1;
 
+	if (BN_num_bits(dh->p) > OPENSSL_DH_MAX_MODULUS_BITS)
+		{
+		DHerr(DH_F_DH_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

@@ -79,6 +79,10 @@
 # include <openssl/dh.h>
 #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
@@ -259,8 +263,10 @@ 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

@@ -274,6 +274,18 @@ 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/rsa/rsa.h

@@ -154,6 +154,17 @@ struct rsa_st
 	BN_BLINDING *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
 
@@ -386,6 +397,7 @@ 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_NULL_BEFORE_BLOCK_MISSING			 113
 #define RSA_R_N_DOES_NOT_EQUAL_P_Q			 127
 #define RSA_R_OAEP_DECODING_ERROR			 121

crypto/rsa/rsa_eay.c

@@ -157,6 +157,28 @@ 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_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;
+ 			}
+ 		}
+ 	
 	BN_init(&f);
 	BN_init(&ret);
 	if ((ctx=BN_CTX_new()) == NULL) goto err;
@@ -600,6 +622,28 @@ 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_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;
+			}
+		}
+
 	BN_init(&f);
 	BN_init(&ret);
 	ctx=BN_CTX_new();

crypto/rsa/rsa_err.c

@@ -129,6 +129,7 @@ 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_NULL_BEFORE_BLOCK_MISSING),"null before block missing"},
 {ERR_REASON(RSA_R_N_DOES_NOT_EQUAL_P_Q)  ,"n does not equal p q"},
 {ERR_REASON(RSA_R_OAEP_DECODING_ERROR)   ,"oaep decoding error"},

ssl/s2_clnt.c

@@ -538,7 +538,8 @@ 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

@@ -1727,7 +1727,7 @@ static 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

@@ -1187,7 +1187,7 @@ 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);