From 5e3225cc44ebdce3a88d04a627e975b3e76a6f9a Mon Sep 17 00:00:00 2001 From: =?utf8?q?Bodo=20M=C3=B6ller?= Date: Thu, 28 Sep 2006 13:45:34 +0000 Subject: [PATCH] Introduce limits to prevent malicious keys being able to cause a denial of service. (CVE-2006-2940) [Steve Henson, Bodo Moeller] --- crypto/dh/dh.h | 7 ++++++- crypto/dh/dh_err.c | 1 + crypto/dh/dh_key.c | 6 ++++++ crypto/dsa/dsa.h | 10 ++++++++-- crypto/dsa/dsa_err.c | 2 ++ crypto/dsa/dsa_ossl.c | 12 +++++++++++ crypto/ec/ec.h | 12 +++++++++-- crypto/ec/ec_asn1.c | 46 +++++++++++++++++++++++++++++++++++++++++++ crypto/ec/ec_err.c | 3 +++ crypto/rsa/rsa.h | 12 +++++++++++ crypto/rsa/rsa_eay.c | 44 +++++++++++++++++++++++++++++++++++++++++ crypto/rsa/rsa_err.c | 1 + 12 files changed, 151 insertions(+), 5 deletions(-) diff --git a/crypto/dh/dh.h b/crypto/dh/dh.h index ecd61f36c1..86499b4c7e 100644 --- a/crypto/dh/dh.h +++ b/crypto/dh/dh.h @@ -73,6 +73,10 @@ #include #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 @@ -239,11 +243,12 @@ void ERR_load_DH_strings(void); /* Reason codes. */ #define DH_R_BAD_GENERATOR 101 -#define DH_R_BN_DECODE_ERROR 103 +#define DH_R_BN_DECODE_ERROR 109 #define DH_R_BN_ERROR 106 #define DH_R_DECODE_ERROR 104 #define DH_R_INVALID_PUBKEY 102 #define DH_R_KEYS_NOT_SET 108 +#define DH_R_MODULUS_TOO_LARGE 103 #define DH_R_NO_PARAMETERS_SET 107 #define DH_R_NO_PRIVATE_VALUE 100 #define DH_R_PARAMETER_ENCODING_ERROR 105 diff --git a/crypto/dh/dh_err.c b/crypto/dh/dh_err.c index 86d8cdd529..ea5aeedd93 100644 --- a/crypto/dh/dh_err.c +++ b/crypto/dh/dh_err.c @@ -95,6 +95,7 @@ static ERR_STRING_DATA DH_str_reasons[]= {ERR_REASON(DH_R_DECODE_ERROR) ,"decode error"}, {ERR_REASON(DH_R_INVALID_PUBKEY) ,"invalid public key"}, {ERR_REASON(DH_R_KEYS_NOT_SET) ,"keys not set"}, +{ERR_REASON(DH_R_MODULUS_TOO_LARGE) ,"modulus too large"}, {ERR_REASON(DH_R_NO_PARAMETERS_SET) ,"no parameters set"}, {ERR_REASON(DH_R_NO_PRIVATE_VALUE) ,"no private value"}, {ERR_REASON(DH_R_PARAMETER_ENCODING_ERROR),"parameter encoding error"}, diff --git a/crypto/dh/dh_key.c b/crypto/dh/dh_key.c index 79984e13bc..cb5abdcf47 100644 --- a/crypto/dh/dh_key.c +++ b/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); diff --git a/crypto/dsa/dsa.h b/crypto/dsa/dsa.h index 8023bb40b0..ff68bc01a4 100644 --- a/crypto/dsa/dsa.h +++ b/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 @@ -284,12 +288,14 @@ void ERR_load_DSA_strings(void); #define DSA_F_SIG_CB 114 /* Reason codes. */ -#define DSA_R_BN_DECODE_ERROR 102 -#define DSA_R_BN_ERROR 103 +#define DSA_R_BAD_Q_VALUE 102 +#define DSA_R_BN_DECODE_ERROR 108 +#define DSA_R_BN_ERROR 109 #define DSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE 100 #define DSA_R_DECODE_ERROR 104 #define DSA_R_INVALID_DIGEST_TYPE 106 #define DSA_R_MISSING_PARAMETERS 101 +#define DSA_R_MODULUS_TOO_LARGE 103 #define DSA_R_NO_PARAMETERS_SET 107 #define DSA_R_PARAMETER_ENCODING_ERROR 105 diff --git a/crypto/dsa/dsa_err.c b/crypto/dsa/dsa_err.c index 0421d4de60..92ccb62e44 100644 --- a/crypto/dsa/dsa_err.c +++ b/crypto/dsa/dsa_err.c @@ -97,12 +97,14 @@ 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_BN_DECODE_ERROR) ,"bn decode error"}, {ERR_REASON(DSA_R_BN_ERROR) ,"bn error"}, {ERR_REASON(DSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE),"data too large for key size"}, {ERR_REASON(DSA_R_DECODE_ERROR) ,"decode error"}, {ERR_REASON(DSA_R_INVALID_DIGEST_TYPE) ,"invalid digest type"}, {ERR_REASON(DSA_R_MISSING_PARAMETERS) ,"missing parameters"}, +{ERR_REASON(DSA_R_MODULUS_TOO_LARGE) ,"modulus too large"}, {ERR_REASON(DSA_R_NO_PARAMETERS_SET) ,"no parameters set"}, {ERR_REASON(DSA_R_PARAMETER_ENCODING_ERROR),"parameter encoding error"}, {0,NULL} diff --git a/crypto/dsa/dsa_ossl.c b/crypto/dsa/dsa_ossl.c index 7a66bcebb5..2fab8dc65a 100644 --- a/crypto/dsa/dsa_ossl.c +++ b/crypto/dsa/dsa_ossl.c @@ -303,6 +303,18 @@ 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); diff --git a/crypto/ec/ec.h b/crypto/ec/ec.h index 8da8e34339..2348e4c4cb 100644 --- a/crypto/ec/ec.h +++ b/crypto/ec/ec.h @@ -96,6 +96,11 @@ extern "C" { # endif #endif + +#ifndef OPENSSL_ECC_MAX_FIELD_BITS +# define OPENSSL_ECC_MAX_FIELD_BITS 661 +#endif + /** Enum for the point conversion form as defined in X9.62 (ECDSA) * for the encoding of a elliptic curve point (x,y) */ typedef enum { @@ -1049,22 +1054,25 @@ void ERR_load_EC_strings(void); #define EC_R_ASN1_UNKNOWN_FIELD 116 #define EC_R_BUFFER_TOO_SMALL 100 #define EC_R_D2I_ECPKPARAMETERS_FAILURE 117 -#define EC_R_DECODE_ERROR 137 +#define EC_R_DECODE_ERROR 142 #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 #define EC_R_INVALID_ARGUMENT 112 #define EC_R_INVALID_COMPRESSED_POINT 110 #define EC_R_INVALID_COMPRESSION_BIT 109 -#define EC_R_INVALID_CURVE 132 +#define EC_R_INVALID_CURVE 141 #define EC_R_INVALID_DIGEST_TYPE 138 #define EC_R_INVALID_ENCODING 102 #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_KEYS_NOT_SET 140 #define EC_R_MISSING_PARAMETERS 124 #define EC_R_MISSING_PRIVATE_KEY 125 diff --git a/crypto/ec/ec_asn1.c b/crypto/ec/ec_asn1.c index dec913b8ad..66ef129293 100644 --- a/crypto/ec/ec_asn1.c +++ b/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) diff --git a/crypto/ec/ec_err.c b/crypto/ec/ec_err.c index 8633760fde..8db5195bcd 100644 --- a/crypto/ec/ec_err.c +++ b/crypto/ec/ec_err.c @@ -204,6 +204,7 @@ static ERR_STRING_DATA EC_str_reasons[]= {ERR_REASON(EC_R_DECODE_ERROR) ,"decode error"}, {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"}, @@ -216,7 +217,9 @@ 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_KEYS_NOT_SET) ,"keys not set"}, {ERR_REASON(EC_R_MISSING_PARAMETERS) ,"missing parameters"}, {ERR_REASON(EC_R_MISSING_PRIVATE_KEY) ,"missing private key"}, diff --git a/crypto/rsa/rsa.h b/crypto/rsa/rsa.h index 31f3792a4c..7f9e10891e 100644 --- a/crypto/rsa/rsa.h +++ b/crypto/rsa/rsa.h @@ -160,6 +160,17 @@ 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 @@ -452,6 +463,7 @@ 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 diff --git a/crypto/rsa/rsa_eay.c b/crypto/rsa/rsa_eay.c index c6ceaee6e7..385439cdc9 100644 --- a/crypto/rsa/rsa_eay.c +++ b/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); diff --git a/crypto/rsa/rsa_err.c b/crypto/rsa/rsa_err.c index 163b143a73..c844aeb911 100644 --- a/crypto/rsa/rsa_err.c +++ b/crypto/rsa/rsa_err.c @@ -155,6 +155,7 @@ 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"}, -- 2.39.2